Associations of lifestyle and genetic risks with obesity and related chronic diseases in the UK Biobank: a prospective cohort study

BACKGROUND

Interplay between lifestyle (LRS) and genetic risk scores (GRS) on obesity and related chronic diseases are under-investigated and necessary for understanding obesity causes and developing prevention strategies.

OBJECTIVES

To investigate independent and joint associations and interactions of LRS and GRS with obesity prevalence and risks of diabetes, cardiovascular disease (CVD), and obesity-related cancer.

METHODS

In this cohort study of 444,957 UK Biobank participants (age: 56.5 ± 8.1 years, body mass index [BMI]: 27.4 ± 4.7 kg/m2), LRS included physical activity, dietary score, sedentary behavior, sleep duration, and smoking (range: 0-20, each factor has 5 levels). GRS was calculated based on 941 genetic variants related to BMI. Both scores were categorized into quintiles. Obesity (n=106,301) was defined as baseline BMI≥30 kg/m2. Incident diabetes (n=16,311), CVD (n=18,076), and obesity-related cancer (n=17,325) were ascertained through linkage to registries over a median of 12-year follow-up.

RESULTS

The LRS and GRS were independently positively associated with all outcomes. Additive interactions of LRS and GRS were observed for all outcomes (P<0.021). Comparing the top versus bottom LRS quintile, prevalence differences (95% confidence intervals) for obesity were 17.8% (15.9%, 19.7%) in the top GRS quintile and 10.7% (8.3%, 13.1%) in the bottom GRS quintile; for diabetes, CVD, and obesity-related cancer, incidence rate differences associated with per standard deviation increase in LRS were greater in the top compared to the bottom GRS quintile. Participants from top quintiles of both LRS and GRS had 6.16-, 3.81-, 1.56-, and 1.44-fold higher odds/risks of obesity, diabetes, CVD, and obesity-related cancer, respectively, compared with those from bottom quintiles of both scores.

CONCLUSIONS

Higher LRS was associated with higher obesity prevalence and risks of related chronic diseases regardless of GRS, highlighting the broad benefits of healthy lifestyles. Additive gene-lifestyle interactions emphasize the public health importance of lifestyle interventions among people with high genetic risks.

Hysterectomy, oophorectomy and risk of non-Hodgkin's lymphoma

Hysterectomy is associated with an increased risk for adverse health outcomes. However, its connection to the risk of non-Hodgkin's lymphoma (NHL) remains unclear. The aims of our study were to investigate the associations between hysterectomy, oophorectomy and risk of NHL and its major subtypes (eg, diffuse large B-cell lymphoma [DLBCL]), and whether these associations were modified by exogenous hormone use. Postmenopausal women (n = 141,621) aged 50-79 years at enrollment (1993-1998) from the Women's Health Initiative were followed for an average of 17.2 years. Hysterectomy and oophorectomy were self-reported at baseline. Incident NHL cases were confirmed by central review of medical records and pathology reports. During the follow-up period, a total of 1719 women were diagnosed with NHL. Hysterectomy, regardless of oophorectomy status, was associated with an increased risk of NHL (hazard ratio [HR] = 1.23, 95% confidence interval [CI]: 1.05-1.44). Oophorectomy was not independently associated with NHL risk after adjusting for hysterectomy. When stratified by hormone use, the association between hysterectomy and NHL risk was confined to women who had never used hormone therapy (HR = 1.35, 95% CI: 1.06-1.71), especially for DLBCL subtype (P for interaction = .01), and to those who had undergone hysterectomy before the age of 55. Our large prospective study showed that hysterectomy was a risk factor of NHL. Findings varied by hormone use. Future studies incorporating detailed information on the types and indications of hysterectomy may deepen our understanding of the mechanisms underlying DLBCL development and its potential interactions with hormone use.

Genetic subtypes of prediabetes, healthy lifestyle, and risk of type 2 diabetes

Prediabetes is a heterogenous metabolic state with various risk for development of type 2 diabetes (T2D). In this study, we used genetic data on 7,227 US Hispanic/Latinos without diabetes from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and 400,149 non-Hispanic whites without diabetes from the UK Biobank (UKBB) to calculate five partitioned polygenetic risk scores (pPRSs) representing various pathways related to T2D. Consensus clustering was performed in participants with prediabetes in HCHS/SOL (n=3,677) and UKBB (n=16,284) separately, based on these pPRSs. Six clusters of individuals with prediabetes with distinctive patterns of pPRSs and corresponding metabolic traits were identified in the HCHS/SOL, five of which were confirmed in the UKBB. Although baseline glycemic traits were similar across clusters, individuals in Cluster 5 and Cluster 6 showed elevated risk of T2D during follow-up compared to Cluster 1 (RR=1.29 [95% CI 1.08-1.53] and1.34 [1.13-1.60], respectively). Inverse associations between a healthy lifestyle score and risk of T2D were observed across different clusters, with a suggestively stronger association observed in Cluster 5 compared to Cluster 1. Among individuals with healthy lifestyle, those in Cluster 5 had a similar risk of T2D compared to those in Cluster 1 (RR=1.03 [0.91-1.18]). This study identified genetic subtypes of prediabetes which differed in risk of progression to T2D and in benefits from healthy lifestyle.

Circulating levels of biomarkers and risk of ductal carcinoma in situ of the breast in the UK Biobank study

Observational studies have shown associations between circulating levels of various biomarkers (eg, total cholesterol [TC], low-density lipoprotein cholesterol [LDL], insulin-like growth factor-1 [IGF-1], C-reactive protein [CRP] and glycated hemoglobin-1c [HbA1c]) and the risk of invasive breast cancer (IBC). Ductal carcinoma in situ of the breast (DCIS) is a nonobligate precursor of IBC and shares several risk factors with it. However, the relationship between these biomarkers and DCIS risk remains unexplored. We studied the association between circulating levels of TC, LDL-C, high-density lipoprotein cholesterol (HDL-C), Lipoprotein (a) (Lp-(a)), IGF-1, CRP and HbA1c, with the risk of DCIS in 156801women aged 40 to 69 years and breast cancer-free at enrolment when blood samples and information on demographic and health-related factors were collected. Incident cases of DCIS were ascertained during the follow-up via linkage to the UK cancer registries Multivariable-adjusted Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of interest. In all, 969 DCIS incident cases were diagnosed during 11.4 years of follow-up. Total cholesterol was inversely associated with the risk of DCIS (HRquintile(Q)5vsQ1  = 0.47, 95% CI: 0.27-0.82, Ptrend  = .008). Conversely, LDL-C was positively associated with DCIS risk (HRQ3vsQ1  = 1.43, 95% CI: 1.01-2.04, HRQ4vsQ1  = 1.60, 95% CI: 1.04-2.47, HRQ5vsQ1  = 2.29, 95% CI: 1.36-3.88, Ptrend  = .004). In postmenopausal women, CRP had a weak positive association with DCIS risk, while HbA1c showed a nonlinear association with the risk. These results, in conjunction with those from previous studies on IBC, provide support for the association of several biomarkers with the risk of an early stage of breast cancer.

Long-Term Effect of Randomization to Calcium and Vitamin D Supplementation on Health in Older Women : Postintervention Follow-up of a Randomized Clinical Trial

BACKGROUND

Although calcium and vitamin D (CaD) supplementation may affect chronic disease in older women, evidence of long-term effects on health outcomes is limited.

OBJECTIVE

To evaluate long-term health outcomes among postmenopausal women in the Women's Health Initiative CaD trial.

DESIGN

Post hoc analysis of long-term postintervention follow-up of the 7-year randomized intervention trial of CaD. (ClinicalTrials.gov: NCT00000611).

SETTING

A multicenter (n = 40) trial across the United States.

PARTICIPANTS

36 282 postmenopausal women with no history of breast or colorectal cancer.

INTERVENTION

Random 1:1 assignment to 1000 mg of calcium carbonate (400 mg of elemental calcium) with 400 IU of vitamin D3 daily or placebo.

MEASUREMENTS

Incidence of colorectal, invasive breast, and total cancer; disease-specific and all-cause mortality; total cardiovascular disease (CVD); and hip fracture by randomization assignment (through December 2020). Analyses were stratified on personal supplement use.

RESULTS

For women randomly assigned to CaD versus placebo, a 7% reduction in cancer mortality was observed after a median cumulative follow-up of 22.3 years (1817 vs. 1943 deaths; hazard ratio [HR], 0.93 [95% CI, 0.87 to 0.99]), along with a 6% increase in CVD mortality (2621 vs. 2420 deaths; HR, 1.06 [CI, 1.01 to 1.12]). There was no overall effect on other measures, including all-cause mortality (7834 vs. 7748 deaths; HR, 1.00 [CI, 0.97 to 1.03]). Estimates for cancer incidence varied widely when stratified by whether participants reported supplement use before randomization, whereas estimates on mortality did not vary, except for CVD mortality.

LIMITATION

Hip fracture and CVD outcomes were available on only a subset of participants, and effects of calcium versus vitamin D versus joint supplementation could not be disentangled.

CONCLUSION

Calcium and vitamin D supplements seemed to reduce cancer mortality and increase CVD mortality after more than 20 years of follow-up among postmenopausal women, with no effect on all-cause mortality.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute of the National Institutes of Health.

BMI and breast cancer risk around age at menopause

BACKGROUND

A high body mass index (BMI, kg/m2) is associated with decreased risk of breast cancer before menopause, but increased risk after menopause. Exactly when this reversal occurs in relation to menopause is unclear. Locating that change point could provide insight into the role of adiposity in breast cancer etiology.

METHODS

We examined the association between BMI and breast cancer risk in the Premenopausal Breast Cancer Collaborative Group, from age 45 up to breast cancer diagnosis, loss to follow-up, death, or age 55, whichever came first. Analyses included 609,880 women in 16 prospective studies, including 9956 who developed breast cancer before age 55. We fitted three BMI hazard ratio (HR) models over age-time: constant, linear, or nonlinear (via splines), applying piecewise exponential additive mixed models, with age as the primary time scale. We divided person-time into four strata: premenopause; postmenopause due to natural menopause; postmenopause because of interventional loss of ovarian function (bilateral oophorectomy (BO) or chemotherapy); postmenopause due to hysterectomy without BO. Sensitivity analyses included stratifying by BMI in young adulthood, or excluding women using menopausal hormone therapy.

RESULTS

The constant BMI HR model provided the best fit for all four menopausal status groups. Under this model, the estimated association between a five-unit increment in BMI and breast cancer risk was HR=0.87 (95% CI: 0.85, 0.89) before menopause, HR=1.00 (95% CI: 0.96, 1.04) after natural menopause, HR=0.99 (95% CI: 0.93, 1.05) after interventional loss of ovarian function, and HR=0.88 (95% CI: 0.76, 1.02) after hysterectomy without BO.

CONCLUSION

The BMI breast cancer HRs remained less than or near one during the 45-55 year age range indicating that the transition to a positive association between BMI and risk occurs after age 55.

Temporal changes in mammographic breast density and breast cancer risk among women with benign breast disease

INTRODUCTION

Benign breast disease (BBD) and high mammographic breast density (MBD) are prevalent and independent risk factors for invasive breast cancer. It has been suggested that temporal changes in MBD may impact future invasive breast cancer risk, but this has not been studied among women with BBD.

METHODS

We undertook a nested case-control study within a cohort of 15,395 women with BBD in Kaiser Permanente Northwest (KPNW; 1970-2012, followed through mid-2015). Cases (n = 261) developed invasive breast cancer > 1 year after BBD diagnosis, whereas controls (n = 249) did not have breast cancer by the case diagnosis date. Cases and controls were individually matched on BBD diagnosis age and plan membership duration. Standardized %MBD change (per 2 years), categorized as stable/any increase (≥ 0%), minimal decrease of less than 5% or a decrease greater than or equal to 5%, was determined from baseline and follow-up mammograms. Associations between MBD change and breast cancer risk were examined using adjusted unconditional logistic regression.

RESULTS

Overall, 64.5% (n = 329) of BBD patients had non-proliferative and 35.5% (n = 181) had proliferative disease with/without atypia. Women with an MBD decrease (≤ - 5%) were less likely to develop breast cancer (Odds Ratio (OR) 0.64; 95% Confidence Interval (CI) 0.38, 1.07) compared with women with minimal decreases. Associations were stronger among women ≥ 50 years at BBD diagnosis (OR 0.48; 95% CI 0.25, 0.92) and with proliferative BBD (OR 0.32; 95% CI 0.11, 0.99).

DISCUSSION

Assessment of temporal MBD changes may inform risk monitoring among women with BBD, and strategies to actively reduce MBD may help decrease future breast cancer risk.

International Pooled Analysis of Leisure-Time Physical Activity and Premenopausal Breast Cancer in Women From 19 Cohorts

PURPOSE

There is strong evidence that leisure-time physical activity is protective against postmenopausal breast cancer risk but the association with premenopausal breast cancer is less clear. The purpose of this study was to examine the association of physical activity with the risk of developing premenopausal breast cancer.

METHODS

We pooled individual-level data on self-reported leisure-time physical activity across 19 cohort studies comprising 547,601 premenopausal women, with 10,231 incident cases of breast cancer. Multivariable Cox regression was used to estimate hazard ratios (HRs) and 95% CIs for associations of leisure-time physical activity with breast cancer incidence. HRs for high versus low levels of activity were based on a comparison of risk at the 90th versus 10th percentiles of activity. We assessed the linearity of the relationship and examined subtype-specific associations and effect modification across strata of breast cancer risk factors, including adiposity.

RESULTS

Over a median 11.5 years of follow-up (IQR, 8.0-16.1 years), high versus low levels of leisure-time physical activity were associated with a 6% (HR, 0.94 [95% CI, 0.89 to 0.99]) and a 10% (HR, 0.90 [95% CI, 0.85 to 0.95]) reduction in breast cancer risk, before and after adjustment for BMI, respectively. Tests of nonlinearity suggested an approximately linear relationship (Pnonlinearity = .94). The inverse association was particularly strong for human epidermal growth factor receptor 2-enriched breast cancer (HR, 0.57 [95% CI, 0.39 to 0.84]; Phet = .07). Associations did not vary significantly across strata of breast cancer risk factors, including subgroups of adiposity.

CONCLUSION

This large, pooled analysis of cohort studies adds to evidence that engagement in higher levels of leisure-time physical activity may lead to reduced premenopausal breast cancer risk.

Metabolic Syndrome and the Risk of Ductal Carcinoma In Situ of the Breast in the UK Biobank

BACKGROUND

Metabolic syndrome (MetS), defined by the presence of three of more metabolic dysregulations such as hyperlipidemia, hyperinsulinemia, central obesity, and hypertension, has been associated with increased risk of cardiovascular disease, diabetes, and various cancers, including invasive breast cancer (IBC). Whether MetS is a risk factor for ductal carcinoma in situ of the breast (DCIS), a nonobligate precursor of IBC, remains unknown.

METHODS

A total of 198,748 women ages 40 to 69 years, DCIS- and IBC-free at enrolment in UK Biobank, were included in the current study. Multivariable-adjusted Cox proportional hazards models were used to estimate the association between MetS and DCIS.

RESULTS

A total of 1,251 DCIS cases were ascertained during an average follow-up of 11.4 years. There was no association between MetS and the risk of DCIS overall, or by menopausal status. Analysis of individual components of MetS showed an association between central obesity (waist circumference ≥88 cm) and increased DCIS risk in postmenopausal women.

CONCLUSIONS

In this prospective study, we found no association between MetS and DCIS risk.

IMPACT

The study findings do not support an association between MetS and this breast cancer precursor.

Uncovering the genetic architecture and evolutionary roots of androgenetic alopecia in African men

Androgenetic alopecia is a highly heritable trait. However, much of our understanding about the genetics of male pattern baldness comes from individuals of European descent. Here, we examined a novel dataset comprising 2,136 men from Ghana, Nigeria, Senegal, and South Africa that were genotyped using a custom array. We first tested how genetic predictions of baldness generalize from Europe to Africa, finding that polygenic scores from European GWAS yielded AUC statistics that ranged from 0.513 to 0.546, indicating that genetic predictions of baldness in African populations performed notably worse than in European populations. Subsequently, we conducted the first African GWAS of androgenetic alopecia, focusing on self-reported baldness patterns at age 45. After correcting for present age, population structure, and study site, we identified 266 moderately significant associations, 51 of which were independent (p-value < 10-5, r2 < 0.2). Most baldness associations were autosomal, and the X chromosomes does not appear to have a large impact on baldness in African men. Finally, we examined the evolutionary causes of continental differences in genetic architecture. Although Neanderthal alleles have previously been associated with skin and hair phenotypes, we did not find evidence that European-ascertained baldness hits were enriched for signatures of ancient introgression. Most loci that are associated with androgenetic alopecia are evolving neutrally. However, multiple baldness-associated SNPs near the EDA2R and AR genes have large allele frequency differences between continents. Collectively, our findings illustrate how evolutionary history contributes to the limited portability of genetic predictions across ancestries.

The Breast Microbiome in Breast Cancer Risk and Progression: A Narrative Review

A decade ago, studies in human populations first revealed the existence of a unique microbial community in the breast, a tissue historically viewed as sterile, with microbial origins seeded through the nipple and/or translocation from other body sites. Since then, research efforts have been made to characterize the microbiome in healthy and cancerous breast tissues. The purpose of this review is to summarize the current evidence for the association of the breast microbiome with breast cancer risk and progression. Briefly, while many studies have examined the breast microbiome in patients with breast cancer, and compared it with the microbiome of benign breast disease tissue or normal breast tissue, these studies have varied widely in their sample sizes, methods, and quality of evidence. Thus, while several large and rigorous cross-sectional studies have provided key evidence of an altered microbiome in breast tumors compared with normal adjacent and healthy control tissue, there are few consistent patterns of perturbed microbial taxa. In addition, only one large prospective study has provided evidence of a relationship between the breast tumor microbiota and cancer prognosis. Future research studies featuring large, well-characterized cohorts with prospective follow-up for breast cancer incidence, progression, and response to treatment are warranted.

The association of the healthy eating index with risk of colorectal cancers (overall and by subsite) among Canadians

BACKGROUND

Healthy dietary patterns characterized by high intake of fruits and vegetables, grains/cereals, and lean meat/fish, and low intake of red/processed meats and refined carbohydrates, have been shown to be associated with reduced risk of colorectal cancer, but evidence regarding their association with colorectal cancer subsites is limited. Hence, this study was conducted to assess the association of a healthy dietary pattern, as reflected in the Healthy Eating Index (HEI) (a composite score based on consumption of various food groups), with risk of colorectal cancer, overall and by subsite.

METHODS

We conducted a case-cohort study in the Canadian Study of Diet, Lifestyle and Health (CSDLH). The study included all cases of incident colorectal cancer in the entire cohort, and an age-stratified subcohort of 3185 women and 2622 men. Cox regression models were used to estimate hazard ratios (HR) for the association between the HEI and the risk of colorectal cancer, overall and by subsite. We also assessed the association by sex and by selected metabolic factors.

RESULTS

For both sexes combined, the highest quintile of the HEI score was inversely associated with risk of colorectal cancer, colon cancer and proximal colon cancer (HR: 0.65; 95% CI: 0. 49-0.85, HR: 0.60, 95% CI: 0.44-0.83 and HR: 0.54, 95% CI: 0.35-0.85, respectively). However, these associations were mostly observed among men (HR: 0.56; 95% CI: 0.38-0.81, HR: 0.44, 95% CI: 0.28-0.69 and HR: 0.26; 95% CI: 0.12-0.56, for colorectal cancer, colon cancer and proximal colon cancer, respectively; p-interactions=0.029, 0.032 and 0.063, respectively). An inverse association was also observed between the HEI and risk of colorectal cancer among normal weight participants, overweight/obese participants, non-smokers, non-alcohol drinkers and participants who were physically inactive.

CONCLUSION

A healthy dietary pattern may reduce risk of colorectal cancer, particularly among men.

Association Between the Healthy Lifestyle Index and Risk of Multimorbidity in the Women's Health Initiative

BACKGROUND

Multimorbidity, defined as the presence of 2 or more chronic health conditions, is increasingly common among older adults. The combination of lifestyle characteristics such as diet quality, smoking status, alcohol intake, physical activity (PA), sleep duration, and body fat as assessed by body mass index (BMI) or waist circumference, and risk of multimorbidity are not well understood.

OBJECTIVES

We investigated the association between the healthy lifestyle index (HLI), generated by combining indicators of diet quality, smoking, alcohol, PA, sleep amount, and BMI, and risk of multimorbidity, a composite outcome that included cardiovascular disease (CVD), diabetes, cancer, and fracture.

METHODS

We studied 62 037 postmenopausal women aged 50-79 years at enrollment in the Women's Health Initiative, with no reported history of CVD, diabetes, cancer, or fracture at baseline. Lifestyle characteristics measured at baseline were categorized and a score (0-4) was assigned to each category. The combined HLI (0-24) was grouped into quintiles, with higher quintiles indicating a healthier lifestyle. Multivariable adjusted estimates of hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the risk of developing multimorbidity were obtained using Cox proportional hazard models.

RESULTS

Over an average follow-up period of 16.3 years, 5 656 women developed multimorbidity. There was an inverse association between the HLI levels and risk of multimorbidity (compared to the HLI_1st quintile: HR_2nd quintile = 0.81 95% CI 0.74-0.83, HR_3rd quintile = 0.77 95% CI 0.71-0.83, HR_4th quintile = 0.70 95% CI 0.64-0.76, and HR_5th quintile = 0.60 95% CI 0.54-0.66; p trend < .001). Similar associations were observed after stratification by age or BMI categories.

CONCLUSIONS

Among postmenopausal women, higher levels of the HLI were associated with a reduced risk of developing multimorbidity.

Menopausal hormone therapy and change in physical activity in the Women's Health Initiative hormone therapy clinical trials

OBJECTIVE

The menopausal transition results in a progressive decrease in circulating estrogen levels. Experimental evidence in rodents has indicated that estrogen depletion leads to a reduction of energy expenditure and physical activity. It is unclear whether treatment with estrogen therapy increases physical activity level in postmenopausal women.

METHODS

A total of 27,327 postmenopausal women aged 50-79 years enrolled in the Women's Health Initiative randomized double-blind trials of menopausal hormone therapy. Self-reported leisure-time physical activity at baseline, and years 1, 3, and 6 was quantified as metabolic equivalents (MET)-h/wk. In each trial, comparison between intervention and placebo groups of changes in physical activity levels from baseline to follow-up assessment was examined using linear regression models.

RESULTS

In the CEE-alone trial, the increase in MET-h/wk was greater in the placebo group compared with the intervention group at years 3 ( P = 0.002) and 6 ( P < 0.001). Similar results were observed when analyses were restricted to women who maintained an adherence rate ≥80% during the trial or who were physically active at baseline. In the CEE + MPA trial, the primary analyses did not show significant differences between groups, but the increase of MET-h/wk was greater in the placebo group compared with the intervention group at year 3 ( P = 0.004) among women with an adherence rate ≥80%.

CONCLUSIONS

The results from this clinical trial do not support the hypothesis that estrogen treatment increases physical activity among postmenopausal women.

Alcohol intake and endogenous sex hormones in women: meta-analysis of cohort studies and Mendelian randomization

Background

The mechanisms underlying alcohol-induced breast carcinogenesis are not fully understood but may involve hormonal changes.

Methods

We investigated cross-sectional associations between self-reported alcohol intake and serum or plasma concentrations of oestradiol, oestrone, progesterone (in pre-menopausal women only), testosterone, androstenedione, DHEAS (dehydroepiandrosterone sulphate) and SHBG (sex hormone binding globulin) in 45 431 pre-menopausal and 173 476 post-menopausal women. We performed multivariable linear regression separately for UK Biobank, EPIC (European Prospective Investigation into Cancer and Nutrition) and EHBCCG (Endogenous Hormones and Breast Cancer Collaborative Group), and meta-analysed the results. For testosterone and SHBG, we also conducted two-sample Mendelian Randomization (MR) and colocalisation using the ADH1B (Alcohol Dehydrogenase 1B) variant (rs1229984).

Results

Alcohol intake was positively, though weakly, associated with all hormones (except progesterone in pre-menopausal women), with increments in concentrations per 10 g/day increment in alcohol intake ranging from 1.7% for luteal oestradiol to 6.6% for post-menopausal DHEAS. There was an inverse association of alcohol with SHBG in post-menopausal women but a small positive association in pre-menopausal women. MR identified positive associations of alcohol intake with total testosterone (difference per 10 g/day increment: 4.1%; 95% CI: 0.6%, 7.6%) and free testosterone (7.8%; 4.1%, 11.5%), and an inverse association with SHBG (-8.1%; -11.3%, -4.9%). Colocalisation suggested a shared causal locus at ADH1B between alcohol intake and higher free testosterone and lower SHBG (PP4: 0.81 and 0.97 respectively).

Conclusions

Alcohol intake was associated with small increases in sex hormone concentrations, including bioavailable fractions, which may contribute to its effect on breast cancer risk.

Inflammatory Bowel Disease and Risk of Global Cardiovascular Diseases and Type 2 Diabetes

BACKGROUND

Inflammatory bowel disease (IBD) was associated with elevated risk of cardiometabolic diseases in observational studies. We aimed to evaluate the observational and genetic associations of Crohn's disease (CD) and ulcerative colitis (UC) with multiple cardiometabolic outcomes.

METHODS

Our phenotypic and genetic association analyses included more than 400 000 participants who were free of major cardiovascular disease and diabetes at recruitment (2006-2010) and were followed up until December 2019 based on the UK Biobank. For the Mendelian randomization (MR) analyses, 415 and 273 single nucleotide polymorphisms associated with CD and UC, respectively, were selected as genetic instruments. Summary-level data on individual cardiometabolic outcomes were obtained from 4 different genome-wide association studies with a total of 2 248 842 participants.

RESULTS

In the multivariable-adjusted observational analyses, CD was associated with higher risks of heart failure (hazard ratio [HR], 1.72; 95% confidence interval, 1.22-2.42) and type 2 diabetes (HR, 2.11; 95% confidence interval, 1.67-2.67) but not with myocardial infarction or ischemic stroke. UC was related to increased risks of all the assessed cardiometabolic diseases (HRs ranged from 1.29 for myocardial infarction to 1.76 for type 2 diabetes). Conversely, neither the genetic risk score for CD nor that for UC was associated with higher risk of developing cardiometabolic diseases. In 2-sample MR analyses, genetically determined CD and UC were not associated with any of the assessed cardiometabolic diseases (all P values >.05).

CONCLUSIONS

Despite confirming the observational associations, our study does not support a causal association between IBD and elevated risk of cardiometabolic diseases.

Endogenous sex steroid hormones and risk of liver cancer among US men: Results from the Liver Cancer Pooling Project

Background & Aims

Incidence rates of liver cancer in most populations are two to three times higher among men than women. The higher rates among men have led to the suggestion that androgens are related to increased risk whereas oestrogens are related to decreased risk. This hypothesis was investigated in the present study via a nested case-control analysis of pre-diagnostic sex steroid hormone levels among men in five US cohorts.

Methods

Concentrations of sex steroid hormones and sex hormone-binding globulin were quantitated using gas chromatography-mass spectrometry and a competitive electrochemiluminescence immunoassay, respectively. Multivariable conditional logistic regression was used to calculate odds ratios (ORs) and 95% CIs for associations between hormones and liver cancer among 275 men who subsequently developed liver cancer and 768 comparison men.

Results

Higher concentrations of total testosterone (OR per one-unit increase in log₂ = 1.77, 95% CI = 1.38-2.29), dihydrotestosterone (OR = 1.76, 95% CI = 1.21-2.57), oestrone (OR = 1.74, 95% CI = 1.08-2.79), total oestradiol (OR = 1.58, 95% CI=1.22-20.05), and sex hormone-binding globulin (OR = 1.63, 95% CI = 1.27-2.11) were associated with increased risk. Higher concentrations of dehydroepiandrosterone (DHEA), however, were associated with a 53% decreased risk (OR = 0.47, 95% CI = 0.33-0.68).

Conclusions

Higher concentrations of both androgens (testosterone, dihydrotestosterone) and their aromatised oestrogenic metabolites (oestrone, oestradiol) were observed among men who subsequently developed liver cancer compared with men who did not. As DHEA is an adrenal precursor of both androgens and oestrogens, these results may suggest that a lower capacity to convert DHEA to androgens, and their subsequent conversion to oestrogens, confers a lower risk of liver cancer, whereas a greater capacity to convert DHEA confers a greater risk.

Impact and implications

This study does not fully support the current hormone hypothesis as both androgen and oestrogen levels were associated with increased risk of liver cancer among men. The study also found that higher DHEA levels were associated with lower risk, thus suggesting the hypothesis that greater capacity to convert DHEA could be associated with increased liver cancer risk among men.

Healthy Lifestyle Index and Risk of Cardiovascular Disease Among Postmenopausal Women With Normal Body Mass Index

Background A lifestyle comprising a healthy diet, light alcohol consumption, no smoking, and moderate or intense physical activity has been associated with reduced risk of cardiovascular disease (CVD). We examined the association of a healthy lifestyle index (HLI), derived from scores for each of these components plus waist circumference, with the risk of incident CVD and CVD subtypes in postmenopausal women with normal body mass index (18.5-<25.0 kg/m²). Methods and Results We studied 40 118 participants in the Women's Health Initiative, aged 50 to 79 years at enrollment, with a normal body mass index and no history of CVD. The HLI score was categorized into quintiles. We estimated multivariable adjusted hazard ratios (HR) and 95% CIs for the association of HLI with risk of CVD and CVD subtypes using Cox regression models. A total of 3821 cases of incident CVD were ascertained during a median follow-up of 20.1 years. Compared with the lowest quintile (unhealthiest lifestyle), higher HLI quintiles showed inverse associations with the risk of CVD (HR_quintile-2=0.74 [95% CI, 0.67-0.81]; HR_quintile-3=0.66 [95% CI, 0.60-0.72]; HR_quintile-4=0.57 [95% CI, 0.51-0.63]; and HR_quintile-5=0.48 [95% CI, 0.43-0.54], P-trend=<0.001). HLI was also inversely associated with risks of stroke, coronary heart disease, myocardial infarction, angina, and coronary revascularization. Subgroup analyses, stratified by age (≤63 years vs >63 years), body mass index (</≥ 22.0 kg/m²), and general health status (absence/presence of hypertension, diabetes, or lipid-lowering drug use) also showed inverse associations between HLI and risk of CVD. Conclusions Among postmenopausal women with a normal body mass index, adherence to a healthy lifestyle is associated with a reduced risk of clinical CVD and CVD subtypes, underscoring the cardiovascular benefits of maintaining a healthy lifestyle, even for women with a healthy weight.

Diabetes, metformin use and risk of non-Hodgkin's lymphoma in postmenopausal women: A prospective cohort analysis in the Women's Health Initiative

Epidemiologic evidence is limited about associations between T2DM, metformin, and the risk of non-Hodgkin's lymphoma (NHL). We aimed to examine associations between T2DM, metformin, and the risk of NHL in the Women's Health Initiative (WHI) Study. Information on T2DM status (diabetes status/types of antidiabetic drug use/diabetes duration) from study enrollment and during follow-up were assessed. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to evaluate associations of T2DM status with risks of overall NHL and its three major subtypes [diffuse large B-cell lymphoma (DLBCL, n = 476), follicular lymphoma (FL, n = 301) and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL, n = 136)] based on multivariable-adjusted Cox proportional hazards models. During a median follow-up of 18.86 years (range, 0.01-25.13; SD ± 6.55), a total of 1637 women developed NHL among 147 885 postmenopausal women. Women with T2DM and with self-reported oral medication use had 38% and 55% higher risk of DLBCL, respectively [multivariable-adjusted model HR = 1.38, 95% CI (1.06-1.81) and HR = 1.55, 95% CI (1.16-2.06)] compared to the reference group (nondiabetics/untreated diabetes). Risks of NHL and DLBCL [multivariable-adjusted model: HR = 1.28, 95% CI (1.06-1.54) and HR = 1.56, 95% CI (1.13-2.14), respectively] were significantly higher in associations with relatively short duration (≤7 years) of diabetes, compared to reference group. Additionally, an increased risk of DLBCL [HR = 1.76, 95% CI (1.13-2.75)] was found in metformin users compared to the reference group. Postmenopausal women who had T2DM, who were oral antidiabetic drug users, especially metformin, and who had a shorter diabetes duration may have higher risks of DLBCL. Further well-designed research is needed to confirm our findings.

Abstract 776: Temporal changes in mammographic breast density and breast cancer risk among women with benign breast disease

Introduction: Benign breast disease (BBD) is associated with increased breast cancer risk, and the magnitude of this risk is characterized by the severity of the histological classification of the biopsy lesion. High mammographic density (MBD) is an independent risk factor for invasive breast cancer. Given that MBD is altered by endogenous and exogenous factors, its temporal changes may impact future breast cancer risk, but this is poorly studied, particularly among high risk BBD patients. In this study, we examined whether MBD changes following a BBD diagnosis were associated with subsequent breast cancer risk.

Methods: We conducted a case-control study within a cohort of 15,395 women aged 18-86 years who were members of the Kaiser Permanente Northwest Region health care system, had a diagnosis of BBD between 1970 and 2012 and were followed through mid-2015. Cases (n=261) were BBD patients who developed invasive breast cancer at least one year after the index BBD diagnosis. Controls were matched (1:1), on age at BBD diagnosis and health plan membership duration and did not develop breast cancer during the follow-up duration. Standardized change in percent MBD per 2 years, categorized as an increase (≥0%), stable/minimal decrease (-5%&lt; to &lt;0) or decrease (≤-5%), was determined from baseline (pre-biopsy) and follow-up (prior to breast cancer diagnosis for cases or matched selection date for controls) mammograms, using computer-assisted software. Associations between MBD change and breast cancer risk overall and stratified by BBD diagnosis age and histology were determined using unconditional logistic regression adjusted for matching factors and other covariates.

Results: At BBD diagnosis (median age (range)=54.6 years (32.4, 86.6)), 64.5% (n=329: n=151 cases and n=178 controls) of women had non-proliferative and 35.5% (n=181: n=110 cases and n=71 controls) had proliferative BBD with or without atypia. Compared to women with stable/minimal MBD decrease, those who experienced a decline ≥5% per 2 years were less likely to develop breast cancer (odds ratio [OR]: 0.64; 95% confidence interval [CI]: 0.38, 1.07). However, among women aged ≥50 years at BBD diagnosis, an MBD decrease ≥5% was significantly associated with reduced breast cancer risk (OR: 0.48; 95%CI: 0.25, 0.92), with the protective effect most apparent for those with proliferative (OR: 0.32; 95%CI: 0.11, 0.99) versus non-proliferative (OR: 0.70; 95%CI: 0.30, 1.64) BBD.

Discussion: Temporal MBD declines were associated with reduced risk of subsequent breast cancer particularly among BBD patients aged ≥50 years and with proliferative BBD diagnoses. These findings suggest that monitoring MBD may be useful in determining risk and that strategies to actively reduce MBD may be helpful in reducing breast cancer risk among high-risk BBD patients.

Funding: Dr. Rohan is supported in part by the Breast Cancer Research Foundation (BCRF-22-140).

Citation Format: Maeve Mullooly, Shaoqi Fan, Ruth M. Pfeiffer, Erin Aiello Bowles, Máire A. Duggan, Roni T. Falk, Kathryn Richert-Boe, Terry Kimes, Jonine D. Figueroa, Thomas E. Rohan, Mustapha Abubakar, Gretchen L. Gierach. Temporal changes in mammographic breast density and breast cancer risk among women with benign breast disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 776.

Circulating immune markers and risks of non-Hodgkin lymphoma subtypes: A pooled analysis

Although prediagnostic circulating concentrations of the immune activation markers soluble CD27 (sCD27), sCD30 and chemokine ligand-13 (CXCL13) have been associated with non-Hodgkin lymphoma (NHL) risk, studies have been limited by sample size in associations with NHL subtypes. We pooled data from eight nested case-control studies to investigate subtype-specific relationships for these analytes. Using polytomous regression, we calculated odds ratios (ORs) with 95% confidence intervals (CIs) relating study-specific analyte tertiles to selected subtypes vs controls (n = 3310): chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL; n = 623), diffuse large B cell lymphoma (DLBCL; n = 621), follicular lymphoma (FL; n = 398), marginal zone lymphoma (MZL; n = 138), mantle cell lymphoma (MCL; n = 82) and T cell lymphoma (TCL; n = 92). We observed associations with DLBCL for elevated sCD27 [OR for third vs first tertile (ORT3 ) = 2.2, 95% CI = 1.6-3.1], sCD30 (ORT3  = 2.0, 95% CI = 1.6-2.5) and CXCL13 (ORT3  = 2.3, 95% CI = 1.8-3.0). We also observed associations with sCD27 for CLL/SLL (ORT3  = 3.3, 95% CI = 2.4-4.6), MZL (ORT3  = 7.7, 95% CI = 3.0-20.1) and TCL (ORT3  = 3.4, 95% CI = 1.5-7.7), and between sCD30 and FL (ORT3  = 2.7, 95% CI = 2.0-3.5). In analyses stratified by time from phlebotomy to case diagnosis, the sCD27-TCL and all three DLBCL associations were equivalent across both follow-up periods (<7.5, ≥7.5 years). For other analyte-subtype comparisons, associations were stronger for the follow-up period closer to phlebotomy, particularly for indolent subtypes. In conclusion, we found robust evidence of an association between these immune markers and DLBCL, consistent with hypotheses that mechanisms related to immune activation are important in its pathogenesis. Our other findings, particularly for the rarer subtypes MZL and TCL, require further investigation.

Association of sleep duration and insomnia with metabolic syndrome and its components in the Women's Health Initiative

BACKGROUND

Epidemiological evidence suggests that inadequate sleep duration and insomnia may be associated with increased risk of metabolic syndrome (MetS). However, longitudinal data with repeated measures of sleep duration and insomnia and of MetS are limited. We examined the association of sleep duration and insomnia with MetS and its components using longitudinal data from the Women's Health Initiative (WHI).

METHODS

The study included postmenopausal women (ages 50-79 years) diabetes-free at enrollment in the WHI, with baseline data on sleep duration (n = 5,159), insomnia (n = 5,063), MetS, and its components. Repeated measures of self-reported sleep duration and insomnia were available from years 1 or 3 of follow-up and of the MetS components from years 3, 6 and 9. Associations were assessed using logistic regression and generalized estimating equations models, and odds ratios and 95% confidence intervals (CI) adjusted for major risk factors were calculated.

RESULTS

In cross-sectional analysis, baseline sleep duration ≥ 9 h was positively associated with MetS (OR = 1.51; 95%CI 1.12-2.04), while sleep duration of 8- < 9 h was associated with waist circumference > 88 cm and triglycerides ≥ 150 mg/dL (OR = 1.18; 95%CI 1.01-1.40 and OR = 1.23; 95%CI 1.05-1.46, respectively). Insomnia had a borderline positive association with MetS (OR = 1.14; 95%CI 0.99-1.31), and significant positive associations with waist circumference > 88 cm and glucose ≥ 100 mg/dL (OR = 1.18; 95%CI 1.03-1.34 and OR = 1.17; 95%CI 1.02-1.35, respectively). In the longitudinal analysis, change from restful sleep to insomnia over time was associated with increased odds of developing MetS (OR = 1.40; 95%CI 1.01-1.94), and of a triglyceride level ≥ 150 mg/dL (OR = 1.48; 95%CI 1.08-2.03).

CONCLUSIONS

Among postmenopausal women in the WHI, sleep duration and insomnia were associated with current and future risk of MetS and some of its components.

Testing the generalizability of ancestry-specific polygenic risk scores to predict prostate cancer in sub-Saharan Africa

BACKGROUND

Genome-wide association studies do not always replicate well across populations, limiting the generalizability of polygenic risk scores (PRS). Despite higher incidence and mortality rates of prostate cancer in men of African descent, much of what is known about cancer genetics comes from populations of European descent. To understand how well genetic predictions perform in different populations, we evaluated test characteristics of PRS from three previous studies using data from the UK Biobank and a novel dataset of 1298 prostate cancer cases and 1333 controls from Ghana, Nigeria, Senegal, and South Africa.

RESULTS

Allele frequency differences cause predicted risks of prostate cancer to vary across populations. However, natural selection is not the primary driver of these differences. Comparing continental datasets, we find that polygenic predictions of case vs. control status are more effective for European individuals (AUC 0.608-0.707, OR 2.37-5.71) than for African individuals (AUC 0.502-0.585, OR 0.95-2.01). Furthermore, PRS that leverage information from African Americans yield modest AUC and odds ratio improvements for sub-Saharan African individuals. These improvements were larger for West Africans than for South Africans. Finally, we find that existing PRS are largely unable to predict whether African individuals develop aggressive forms of prostate cancer, as specified by higher tumor stages or Gleason scores.

CONCLUSIONS

Genetic predictions of prostate cancer perform poorly if the study sample does not match the ancestry of the original GWAS. PRS built from European GWAS may be inadequate for application in non-European populations and perpetuate existing health disparities.

Proton Pump Inhibitor Use and Obesity-Associated Cancer in the Women's Health Initiative

Proton pump inhibitors (PPIs) have off-target activity on fatty acid synthase (FASN), a critical enzyme in energy balance and cancer growth. We evaluated risk of common obesity-related cancers: breast, colorectal (CRC), and endometrial, with use of PPI and histamine-2 receptor antagonists (H2RA) in 124,931 postmenopausal women enrolled in the Women's Health Initiative. Incident cancer cases were physician-adjudicated. Cox proportional hazards models were used to estimate multivariable hazard ratios (HR) and 95% confidence intervals (CI) for cancer incidence after year 3. There were 7956 PPI ever users and 9398 H2RA only users. Ever use of either PPI or H2RA was not associated with risk of breast cancer (n = 9186) nor risk of endometrial cancer (n = 1231). The risk of CRC (n = 2280) was significantly lower in PPI users (HR = 0.75, 95% CI = 0.61-0.92), but not in H2RA users (HR = 1.13, 95% CI = 0.97-1.31). The association of PPI use with CRC was apparent regardless of BMI or NSAID use, and was stronger with longer PPI duration (p = 0.006) and potency (p = 0.005). The findings that PPI use, but not H2RA use, demonstrate an inverse dose-response relationship with risk of CRC is consistent with preclinical data showing FASN inhibition prevents colon cancer progression and supports a role of PPI in CRC prevention.

Association of Prediagnostic Serum Levels of Vitamin D with Risk of Ductal Carcinoma In Situ of the Breast in the UK Biobank Cohort Study

BACKGROUND

Higher circulating levels of vitamin D [25(OH)D] have been associated with reduced risk of developing invasive breast cancer. However, their association with risk of ductal carcinoma in situ (DCIS) of the breast has received little attention.

METHODS

We examined the association of serum vitamin D with risk of DCIS in 231,203 women, aged 40 to 69 years at enrollment in the UK Biobank cohort study. Multivariable Cox proportional hazards models were used to estimate HRs and 95% confidence intervals for the association of vitamin D with DCIS risk.

RESULTS

There was no association between serum 25(OH)D levels and risk of DCIS overall, or by menopausal status. The association was not modified by body mass index category, family history of breast cancer, or current use of menopausal hormone therapy.

CONCLUSIONS

In this large prospective cohort study, we did not observe an association between circulating serum levels of vitamin D and risk of DCIS.

IMPACT

While previous studies have suggested that serum vitamin D has an inverse association with risk of invasive breast cancer, the present results do not provide evidence for an association with DCIS, a non-obligate precursor of invasive disease.

Proton Pump Inhibitor Use and Obesity-Associated Cancers in the Women's Health Initiative

PURPOSE

Proton pump inhibitors (PPIs) inhibit fatty acid synthase (FAS), a critical enzyme in lipogenesis, energy balance, and cancer cell survival. We aimed to evaluate the association of PPI use with incidence of common obesity- related cancers in women: postmenopausal breast, colorectal, and endometrial cancers.

METHODS

Our study included 124,931 postmenopausal who were enrolled in the Women's Health Initiative (WHI) observational study and clinical trials, and had responded to a year 3 follow-up assessment. We examined prescription and over the counter use of PPI and/or histamine 2 receptor antagonists (H2RA) at baseline and year 3, to isolate potential effects of FAS inhibition by PPI rather than simply acid suppression. Incident cancer cases were physician-adjudicated. Cox proportional hazard regression models were used to estimate multivariable hazard ratios (HR) and 95% confidence intervals (CI) for associations between PPI and/or H2RA use and cancer incidence after year 3.

RESULTS

There were 7956 PPI ever users (with or without H2RA use) and 9398 H2RA only users. PPI or H2RA use was not associated with risk of breast cancer (n=9186 cases), compared to women who did not use either agent (HR 1.01, 95% CI 0.93-1.10 and HR 0.95 95% CI 0.87-1.03, respectively). The incidence of colorectal cancer (n=2280) was significantly lower in PPI users (HR 0.75, 95% CI 0.61-0.92), but not in H2RA users (HR 1.13, 95% CI 0.97-1.31). This association was strengthened with increasing duration (p=0.006) and potency (p=0.005) of PPI use and held regardless of BMI or NSAID use. PPI or H2RA use was not associated with endometrial cancer (n=1231) (HR 0.81, 95% CI 0.61-1.07 and HR 1.13, 95% CI 0.91-1.40, respectively), but showed a trend in decreased risk with increasing PPI potency (P=0.048).

CONCLUSIONS

Among postmenopausal women, PPI use, but not H2RA use, demonstrated an inverse, dose-responsive association with colorectal cancer incidence. This was consistent with preclinical data that FAS inhibition prevents colon cancer progression and supports further investigation of this commonly used medication as a cancer preventive agent. PPI use was not associated with incidence of breast or endometrial cancer.

Abstract SY25-02: Double-edged “soil”: Stromal microenvironment in breast cancer development

Double-edged “Soil”: Stromal Microenvironment in Breast Cancer Development

Mustapha Abubakar, MD, PhD1; Shaoqi Fan, MPH1; Máire A. Duggan, MD, FRCPC2; Ruth M. Pfeiffer, PhD1; Scott Lawrence, M.S.3; Kathryn Richert-Boe, MD4; Andrew G. Glass, MD4; Teresa M. Kimes, MS4; Jonine D. Figueroa, PhD, MPH5; Thomas E. Rohan, MBBS, PhD6; Gretchen L. Gierach, PhD, MPH1.

Affiliations 1Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health (NIH), USA2Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, T2N2Y9, Alberta, Canada3Molecular and Digital Pathology Laboratory, Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick, MD 217024Kaiser Permanente Center for Health Research, Portland, Oregon 5Usher Institute of Population Health Sciences and Informatics, The University of Edinburgh, Scotland, UK6Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, 10461

Deceased

Background Over a century after Paget’s postulation of the “seed” and “soil” hypothesis of breast cancer metastasis, understanding of the role of the “soil” (i.e., local or distant stromal microenvironment) in supporting and promoting the growth and dissemination of “seed” tumor cells has increased considerably. However, the role of the stromal microenvironment in early stages of breast cancer development, including tissue origins of etiologic heterogeneity, remains poorly understood. To date, the prevailing model of breast cancer development involves a linear sequence of epithelial changes that begin from normal epithelium, progress to flat epithelial atypia (FEA), develop into atypical ductal hyperplasia, transform into ductal carcinoma in situ (DCIS), and culminate in the emergence of invasive breast cancer. An alternative model proposes the evolution of FEA from usual ductal hyperplasia, but this is not supported by a clear genetic link between the two. Notably, established models of breast cancer development are predicated almost exclusively on sequences of epithelial changes. Although recent efforts have shed light on the significance of stromal microenvironment in DCIS to invasive breast cancer progression, its role in breast cancer development following benign breast disease (BBD) is less well-studied. MethodsIn this case-control study, nested within a cohort of 15,395 BBD patients from Kaiser Permanente Northwest (1970-2012) who were followed for subsequent development of invasive breast cancer, we evaluated archival diagnostic, formalin-fixed and paraffin-embedded tissue blocks using high-accuracy machine learning algorithms for the detailed characterization of stromal microenvironment on digitized H&E-stained breast biopsy sections. Stromal phenotypes, including total stromal-to-epithelial ratio (TSER), dense stromal-to-epithelial ratio (DSER), loose stromal-to-epithelial ratio (LSER) and stromal cellular density (SCD) were defined based on the distributions of total stromal area, dense (mostly fibrous/collagenized, inter-lobular) stroma, loose (mostly pale, intra-lobular or remodeled) stroma, and stromal cellularity, respectively. Relationships between stromal features and invasive breast cancer incidence through 2012 were assessed in multivariable conditional logistic regression models adjusted for BBD histological classification, body mass index, menopausal status/menopausal hormone therapy use, parity and age at first live birth (AFLB), family history of breast cancer (FHBC), oophorectomy, and mammographic density. Analyses were performed overall and by BBD histologic classification. We also evaluated associations between stromal features and breast cancer risk according to tumor characteristics that define divergent etiologic pathways, namely estrogen receptor (ER) expression and histologic grade. Results The current analysis is comprised of 486 cases and 487 controls, representing 95% of the case-control study population, for whom digitized H&E-stained sections were suitable for image analysis. The median age at diagnosis was 51.4 (range=18-86) years. ~55% of the participants were either overweight (30.1%) or obese (24.5%) at BBD diagnosis, and 69% had non-proliferative disease (NPD), 28% proliferative disease (PD) without atypia, and 3% atypical hyperplasia (AH). 13% of BBD biopsies contained simple fibroadenoma, ~2% complex fibroadenoma, 8% sclerosing adenosis, 5% radial scar, and 14% columnar cell lesions. The median (range) values (%) of total, dense, and loose connective tissue stroma were 39.3% (0.6-89.9%), 25.1% (0.1-84.5%), and 8.6% (0.2-59.0%), respectively. On average, BBD lesions contained ~6 times more stroma than epithelium. Average TSER, DSER, LSER, and SCD were 6.3, 4.4, 1.8, and 7.5%, respectively. Overall, increasing TSER was associated with decreasing risk of breast cancer [OR(95% CI)Q4 vs Q1=0.51(0.32, 0.82); p-trend=0.009]. The protective effect of TSER was, however, stronger in relation to DSER [OR(95% CI)Q4 vs Q1=0.48(0.29, 0.79); p-trend=0.007] than LSER [OR(95% CI)Q4 vs Q1=0.84(0.52, 1.36); p-trend=0.70]. Conversely, increasing SCD was statistically significantly associated with increasing breast cancer risk [OR(95% CI)Q4 vs Q1=2.21 (1.38, 3.56); p-trend=0.001]. Although findings were stronger among patients with NPD than PD, there was no heterogeneity in the association by BBD histology. Of the stromal features, DSER and SCD were most predictive of breast cancer risk but these were not independent of one another. To test their joint association with risk, we combined categories [low (&lt;25th percentile), intermediate (25th–75th percentile), and high (&gt;75th percentile) for each variable] in a composite, stromal disruption (SD), variable as follows: 1) no SD (high DSER and low SCD); 2) minimal disruption (high DSER and intermediate SCD, or vice versa); 3) moderate SD (intermediate DSER and high SCD, or vice versa); and 4) substantial SD (low DSER and high SCD). BBD patients with moderate [OR(95% CI)=1.74(1.01, 2.99)] or substantial [OR(95% CI)=2.70(1.51, 4.84)] SD were at statistically significantly elevated risk of breast cancer than those with no SD. Younger women, those with proliferative BBD, parous and AFLB &lt;30 years, positive FHBC, absent involution, and being postmenopausal were statistically significantly more likely to develop BBDs with substantial SD than those with no SD. Substantial SD was associated with elevated risk of both ER+ [OR(95% CI)=1.97(1.16, 3.36)] and ER- [OR(95% CI)=2.09(0.77, 5.69)] breast cancer. In terms of grade, substantial SD was more strongly associated with risks of high [OR(95% CI)=3.17(1.28, 7.85)] and intermediate [OR(95% CI)=2.30(1.10, 4.83)] than low [OR(95% CI)=1.61(0.74, 3.50)] grade tumors overall (p-heterogeneity=0.44). This association was stronger among patients with NPD [OR(95% CI) substantial SD vs no SD=5.75(2.04, 16.09); 2.83(1.15, 6.97); and 1.36(0.53, 3.46) for high, intermediate, and low grade tumors, respectively (p-heterogeneity=0.03)]. Because AH has been implicated in the development of ER+/low grade but not ER+/high grade tumors, we further evaluated the role of AH and SD in ER+ breast cancer risk: contrasting patterns were observed in associations between AH, substantial SD, and risk of ER+ tumors defined by levels of histologic grade. While AH more strongly predisposed to risk of low [OR(95% CI)=6.32(1.09, 20.08)] than high [OR(95% CI)=1.04(0.10, 11.24)] grade ER+ tumors, substantial SD more strongly predisposed to risk of high [OR(95% CI)=5.28(1.54, 18.10)] than low [OR(95% CI)=1.52(0.76, 3.06)] grade ER+ tumors.Conclusion Components of the stromal microenvironment in BBD showed disparate associations with breast cancer risk factors and risk of subsequent invasive breast cancer. In particular, increasing ratio of dense (mostly fibrous/collagenized and inter-lobular), but not loose (mostly pale/myxoid, intra-lobular, remodeled), connective tissue stroma to epithelium was strongly associated with reduced risk of breast cancer. Conversely, increasing stromal cellularity was associated with increasing risk of breast cancer. In combination, decreasing amounts of dense stroma and concomitant increase in loose stroma, epithelial volume, and stromal cellularity resulted in a stromal disruption phenotype that was strongly associated with increased breast cancer risk overall, but particularly of aggressive high grade tumors. These results were independent of BBD histologic diagnosis. Many of the observed risk factor associations with stromal microenvironment features were consistent with their breast cancer risk relationships, suggesting that stromal changes may reflect cumulative exposure to breast cancer risk factors. These findings provide new etiologic insights into stromal role in breast cancer risk, including tissue origins of breast cancer etiologic heterogeneity, with the potential to aid risk stratification and clinical decision-making for BBD patients.

Citation Format: Mustapha Abubakar, Shaoqi Fan, Maire A. Duggan, Ruth M. Pfeiffer, Scott Lawrence, Kathryn Richert-Boe, Andrew Glass, Teresa M. Kimes, Jonine D. Figueroa, Thomas E. Rohan, Gretchen L. Gierach. Double-edged “soil”: Stromal microenvironment in breast cancer development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr SY25-02.

Racial disparity in distant recurrence-free survival in patients with localized breast cancer: A pooled analysis of National Surgical Adjuvant Breast and Bowel Project trials

BACKGROUND

Black race is associated with worse outcome in patients with breast cancer. The distant relapse-free survival (DRFS) between Black and White women with localized breast cancer who participated in National Cancer Institute-sponsored clinical trial was evaluated.

METHODS

Pooled data were analyzed from 8 National Surgical Adjuvant Breast and Bowel Project (NSABP) trials including 9702 women with localized breast cancer treated with adjuvant chemotherapy (AC, n = 7485) or neoadjuvant chemotherapy (NAC, n = 2217), who self-reported as Black (n = 1070) or White (n = 8632) race. The association between race and DRFS was analyzed using log-rank tests and multivariate Cox regression.

RESULTS

After adjustment for covariates including age, tumor size, nodal status, body mass index and taxane use, and treatment (AC vs NAC), Black race was associated with an inferior DRFS in estrogen receptor-positive (ER+; hazard ratio [HR], 1.24; 95% CI, 1.05-1.46; P = .01), but not in ER- disease (HR, 0.97; 95% CI, 0.83-1.14; P = .73), and significant interaction between race and ER status was observed (P = .03). There was no racial disparity in DRFS among patients with pathologic complete response (pCR) (log-rank P = .8). For patients without pCR, Black race was associated with worse DRFS in ER+ (HR, 1.67; 95% CI, 1.14-2.45; P = .01), but not in ER- disease (HR, 0.91; 95% CI, 0.65-1.28; P = .59).

CONCLUSIONS

Black race was associated with significantly inferior DRFS in ER+ localized breast cancer treated with AC or NAC, but not in ER- disease. In the NAC group, racial disparity was also observed in patients with residual ER+ breast cancer at surgery, but not in those who had pCR.

LAY SUMMARY

Black women with breast cancer have worse outcomes compared with White women. We investigated if this held true in the context of clinical trials that provide controlled treatment setting. Black women with cancer expressing estrogen receptors (ERs) had worse outcome than White women. If breast cancers did not express ERs, there was no racial disparity in outcome. We also observed racial disparity in women who received chemotherapy before their cancer was removed, but only if they had cancer expressing ERs and residual disease on completion of treatment. If the cancer disappeared with presurgical chemotherapy, there was no racial disparity.

Healthy lifestyle index and risk of pancreatic cancer in the Women's Health Initiative

PURPOSE

Lifestyle factors such as smoking, alcohol, body weight, physical activity, and diet quality have been associated with the risk of pancreatic cancer. However, studies of their combined association in women are limited.

METHODS

Data on smoking habits, alcohol intake, diet composition, recreational physical activity, body weight, and waist circumference, obtained at recruitment for 136,945 postmenopausal women (aged 50-79 years) participating in the Women's Health Initiative study, were categorized separately, with higher scores for each variable assigned to the categories representing healthier behaviors. The combined healthy lifestyle index (HLI) score, created by summing the scores for each risk factor, was grouped into quartiles. We used multivariable-adjusted Cox regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) for pancreatic cancer risk in association with the HLI.

RESULTS

Over an average follow-up period of approximately 16.0 years, 1,119 incident cases of pancreatic cancer were ascertained. Compared to women in the lowest HLI quartile, those in the upper quartiles (qt) had a reduced risk of pancreatic cancer (multivariable-adjusted HRqt3rd 0.83, 95% CI 0.74-0.99; and HRqt4th 0.74, 95% CI 0.62-0.88, respectively, p trend = 0.001). Use of waist circumference instead of BMI in the HLI score yielded similar results. Among women who were either non-diabetic or non-smokers, high HLI was also associated with reduced risk (HRqt4th 0.78, 95% CI 0.65-0.85 and HRqt4th 0.80, 95% CI 0.66-0.97, respectively). Stratification by BMI categories (18.5- < 25.0, 25.0- < 30.0 and > 30.0 kg/m2) showed similar results in all groups.

CONCLUSIONS

Our findings suggest that in postmenopausal women, a healthy lifestyle is associated with reduced risk of pancreatic cancer.

Combining TMEM Doorway Score and MenaCalc Score Improves the Prediction of Distant Recurrence Risk in HR+/HER2- Breast Cancer Patients

PURPOSE

to develop several digital pathology-based machine vision algorithms for combining TMEM and MenaCalc scores and determine if a combination of these biomarkers improves the ability to predict development of distant metastasis over and above that of either biomarker alone.

METHODS

This retrospective study included a subset of 130 patients (65 patients with no recurrence and 65 patients with a recurrence at 5 years) from the Calgary Tamoxifen cohort of breast cancer patients. Patients had confirmed invasive breast cancer and received adjuvant tamoxifen therapy. Of the 130 patients, 86 cases were suitable for analysis in this study. Sequential sections of formalin-fixed paraffin-embedded patient samples were stained for TMEM doorways (immunohistochemistry triple staining) and MenaCalc (immunofluorescence staining). Stained sections were imaged, aligned, and then scored for TMEM doorways and MenaCalc. Different ways of combining TMEM doorway and MenaCalc scores were evaluated and compared to identify the best performing combined marker by using the restricted mean survival time (RMST) difference method.

RESULTS

the best performing combined marker gave an RMST difference of 5.27 years (95% CI: 1.71-8.37), compared to 3.56 years (95% CI: 0.95-6.1) for the associated standalone TMEM doorway analysis and 2.94 years (95% CI: 0.25-5.87) for the associated standalone MenaCalc analysis.

CONCLUSIONS

combining TMEM doorway and MenaCalc scores as a new biomarker improves prognostication over that observed with TMEM doorway or MenaCalc Score alone in this cohort of 86 patients.

Abstract P2-10-04: Breast cancer risk assessment tool (BCRAT) predicted breast cancer incidence and breast cancer mortality in the women's health initiative

Purpose Commonly used breast cancer risk models estimate breast cancer incidence. However, such model performance, re-purposed to predict breast cancer mortality, are largely unknown. Therefore, we examined whether the BCRAT model predicts long-term breast cancer mortality in postmenopausal women in the WHI. Participants and Methods Of 161,808 WHI participants aged 50-79 years, after exclusions,145,408 were in the analysis. BCRAT risk was calculated, with incident breast cancers verified by central medical record review. Breast cancer mortality was related to BCRAT 5-year risk groups (&lt; 1%, 1-2.99%, ≥ 3%) using unadjusted Cox proportional hazard models and in age-stratified, multi-variable models. An addition analysis compared proportion of participants with BCRAT risk ≥ 1.67% and ≥ 3% (former and current prevention thresholds). Results Of 145,408 participants, the ≥1.67% and the ≥3.0% risk groups included 40% and 9% of participants, respectively. Compared to women with BCRAT&lt;1% risk, women with BCRAT ≥ 3% risk had more common breast cancer family history and lower BMI. After 20 years median follow-up, with 8,849 breast cancers and 1,076 deaths from breast cancer, risk of death from breast cancer in BCRAT risk group ≥ 3% was not higher compared to BCRAT risk group &lt;1%. (Hazard Ratio [HR] 1.06 95% Confidence Interval [CI] 0.80-1.40, P = 0.76). Similarly, risk of death from breast cancer in BCRAT risk group 1-2.99% was not higher compared to BCRAT risk group &lt;1 (HR 1.15 95% CI 0.93-1.43). Conclusions Current guideline recommendation for threshold for endocrine-targeted interventions substantially reduces postmenopausal prevention candidates from 40% to &lt;10%. The BCRAT prediction model, even at the ≥ 3% 5-year risk threshold, does not identify women at significantly increased risk of death from breast cancer.

Citation Format: Rebecca Nelson, Kathy Pan, Rowan Chlebowski, Thomas E Rohan, Joanne Mortimer, Jean Wactawski-Wende, Dorothy Lane, Laura Kruper. Breast cancer risk assessment tool (BCRAT) predicted breast cancer incidence and breast cancer mortality in the women's health initiative [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-10-04.

Adiposity and breast, endometrial, and colorectal cancer risk in postmenopausal women: Quantification of the mediating effects of leptin, C-reactive protein, fasting insulin, and estradiol

BACKGROUND

Mechanisms underlying the adiposity-cancer relationship are incompletely understood. We quantified the mediating roles of C-reactive protein (CRP), leptin, fasting insulin, and estradiol in the effect of adiposity on estrogen receptor (ER)-positive breast, endometrial, and colorectal cancer risk in postmenopausal women.

METHODS

We used a case-cohort study within the Women's Health Initiative Observational Study, analyzed as a cumulative sampling case-control study. The study included 188 breast cancer cases, 98 endometrial cancer cases, 193 colorectal cancer cases, and 285 controls. Interventional indirect and direct effects on the risk ratio (RR) scale were estimated using causal mediation analysis.

RESULTS

For breast cancer, the total effect RR for BMI ≥30 versus ≥18.5-<25 kg/m2 was 1.87 (95%CI,1.11-3.13). The indirect effect RRs were 1.38 (0.79-2.33) through leptin and CRP, 1.58 (1.17-2.43) through insulin, and 1.11 (0.98-1.30) through estradiol. The direct effect RR was 0.82 (0.39-1.68). For endometrial cancer, the total effect RR was 2.12 (1.12-4.00). The indirect effect RRs were 1.72 (0.85-3.98) through leptin and CRP, 1.42 (0.96-2.26) through insulin, and 1.24 (1.03-1.65) through estradiol. The direct effect RR was 0.70 (0.23-2.04). For colorectal cancer, the total effect RR was 1.70 (1.03-2.79). The indirect effect RRs were 1.04 (0.61-1.72) through leptin and CRP, 1.36 (1.00-1.88) through insulin, and 1.02 (0.88-1.17) through estradiol. The direct effect RR was 1.16 (0.58-2.43).

CONCLUSION

Leptin, CRP, fasting insulin, and estradiol appear to mediate the effect of high BMI on cancer risk to different extents, with likely varying degrees of importance between cancers. These insights might be important in developing interventions to modify obesity-associated cancer risk in postmenopausal women.

Overall and central obesity and prostate cancer risk in African men

PURPOSE

African men are disproportionately affected by prostate cancer (PCa). Given the increasing prevalence of obesity in Africa, and its association with aggressive PCa in other populations, we examined the relationship of overall and central obesity with risks of total and aggressive PCa among African men.

METHODS

Between 2016 and 2020, we recruited 2,200 PCa cases and 1,985 age-matched controls into a multi-center, hospital-based case-control study in Senegal, Ghana, Nigeria, and South Africa. Participants completed an epidemiologic questionnaire, and anthropometric factors were measured at clinic visit. Multivariable logistic regression was used to examine associations of overall and central obesity with PCa risk, measured by body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR), respectively.

RESULTS

Among controls 16.4% were obese (BMI ≥ 30 kg/m2), 26% and 90% had WC > 97 cm and WHR > 0.9, respectively. Cases with aggressive PCa had lower BMI/obesity in comparison to both controls and cases with less aggressive PCa, suggesting weight loss related to cancer. Overall obesity (odds ratio: OR = 1.38, 95% CI 0.99-1.93), and central obesity (WC > 97 cm: OR = 1.60, 95% CI 1.10-2.33; and WHtR > 0.59: OR = 1.68, 95% CI 1.24-2.29) were positively associated with D'Amico intermediate-risk PCa, but not with risks of total or high-risk PCa. Associations were more pronounced in West versus South Africa, but these differences were not statistically significant.

DISCUSSION

The high prevalence of overall and central obesity in African men and their association with intermediate-risk PCa represent an emerging public health concern in Africa. Large cohort studies are needed to better clarify the role of obesity and PCa in various African populations.

Sustained Weight Loss, Weight Cycling, and Weight Gain During Adulthood and Pancreatic Cancer Incidence in the Women's Health Initiative

Pancreatic cancer (PC) is the fourth leading cause of cancer mortality among women in the United States. Obesity is positively associated with PC risk. Current health recommendations focus on weight maintenance for healthy-weight individuals and weight loss for overweight/obese individuals; however, little research has assessed associations between PC risk and changes in weight throughout the life course. Using prospective cohort study data, we examined the relationship between baseline adulthood weight patterns self-reported between 1993 and 1998 and PC risk in 136,834 postmenopausal women with 873 incident PC cases through September 30, 2015, in the Women's Health Initiative. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models, adjusting for age, smoking habits, heavy alcohol consumption, and body mass index. Compared with women with stable weight, no significant associations were found between steady weight gain (HR = 1.01, 95% CI: 0.83, 1.22), sustained weight loss (HR = 1.26, 95% CI: 0.85, 1.87), or weight cycling patterns (HR = 1.08, 95% CI: 0.89, 1.30) and PC. Results were similar when the outcome definition was restricted to pancreatic adenocarcinoma cases. Overall, we did not find evidence to suggest that weight changes in adulthood significantly impact PC risk among postmenopausal women.

The association of predicted resting energy expenditure with risk of breast cancer among postmenopausal women in the Women's Health Initiative cohort

Obesity and obesity-related metabolic disorders, such as obesity and chronic inflammation, have been positively associated both with postmenopausal breast cancer and with resting energy expenditure (REE). However, there is limited epidemiological evidence on the associations between REE and risk of postmenopausal breast cancer. We used multivariable Cox proportional hazards models to examine the association between predicted REE (calculated using the Ikeda, Livingston and Mifflin equations) and risk of postmenopausal breast cancer overall and by subtypes, and by level of body fat) among 137,305 postmenopausal women in the Women's Health Initiative (WHI). All predicted REEs were positively associated with risk of invasive breast cancer (HRq5 vs q1: 1.69; 95% CI: 1.57-1.81, HR: 1.69; 95% CI: 1.57-1.82 and HR: 1.68; 95% CI: 1.56-1.80 for Ikeda, Livingston and Mifflin, respectively). These positive associations were observed irrespective of the hormone receptor subtype, grade and stage of the tumors, but were most pronounced for estrogen receptor positive/progesterone receptor positive tumors. After additional adjustment for BMI, the associations were mostly attenuated and remained statistically significant for most of the outcomes. We also observed an interaction between the predicted REEs and BMI, with the associations being somewhat stronger among normal weight and overweight women than among obese women (pinteractions <0.05). Our findings indicate that relatively high REE is associated with increased risk of invasive breast cancer among postmenopausal women (particularly for the obesity-related tumor subtypes), irrespective of the equation used. Further studies using more objective measures of REE are, however, needed to confirm our findings.

Physical activity and risk of benign proliferative epithelial disorders of the breast, in the Women's Health Initiative

BACKGROUND

Recreational physical activity (PA) has been shown to be inversely associated with breast cancer risk. However, the association of recreational PA with benign proliferative epithelial disorders (BPED) of the breast, conditions associated with increased risk of breast cancer, has not been adequately studied.

METHODS

We used data from an ancillary study of benign breast disease conducted among the 68 132 postmenopausal women (aged 50-79 at recruitment) participating in the Women's Health Initiative randomized clinical trials. All clinical trial participants underwent annual or biennial mammogram screening. During the follow-up, for women who reported breast biopsies but were cancer free, the associated histological sections were obtained and subjected to standardized central pathology review. Self-reported recreational PA at baseline (n = 61 684) and at 3 years of the follow-up (n = 55 923) were quantified as metabolic equivalents [MET]-h/week. There were 1624 confirmed BPED cases during an average follow-up time of 7.7 years. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Higher average PA over 4 years was associated with lower risk of non-atypical BPED (P-trend = 0.02). There was a 6% lower risk of non-atypical BPED for every 5 MET-h/week increase between baseline and year 3 (HR = 0.94, 95% CI 0.89-0.99). Compared with women who remained inactive (PAbaseline and PAyear3 <9 MET-h/week), those who became active (PAbaseline<9 MET-h/week to PAyear3 ≥9 MET-h/weekee), remained active (PAbaseline and PAyear3 ≥9 MET-h/week), or decreased activity (PAbaseline ≥9 MET-h/week to PAyear3 <9 MET-h/week) had lower BPED risk.

CONCLUSIONS

Recreational physical activity after menopause was associated with lower BPED risk among postmenopausal women.

Body Fat Distribution, Cardiometabolic Traits, and Risk of Major Lower-Extremity Arterial Disease in Postmenopausal Women

OBJECTIVE

To assess the relationship between body fat distribution and incident lower-extremity arterial disease (LEAD).

RESEARCH DESIGN AND METHODS

We included 155,925 postmenopausal women with anthropometric measures from the Women's Health Initiative who had no known LEAD at recruitment. A subset of 10,894 participants had body composition data quantified by DXA. Incident cases of symptomatic LEAD were ascertained and adjudicated through medical record review.

RESULTS

We identified 1,152 incident cases of LEAD during a median 18.8 years follow-up. After multivariable adjustment and mutual adjustment, waist and hip circumferences were positively and inversely associated with risk of LEAD, respectively (both P-trend < 0.0001). In a subset (n = 22,561) where various cardiometabolic biomarkers were quantified, a similar positive association of waist circumference with risk of LEAD was eliminated after adjustment for diabetes and HOMA of insulin resistance (P-trend = 0.89), whereas hip circumference remained inversely associated with the risk after adjustment for major cardiometabolic traits (P-trend = 0.0031). In the DXA subset, higher trunk fat (P-trend = 0.0081) and higher leg fat (P-trend < 0.0001) were associated with higher and lower risk of LEAD, respectively. Further adjustment for diabetes, dyslipidemia, and blood pressure diminished the association for trunk fat (P-trend = 0.49), yet the inverse association for leg fat persisted (P-trend = 0.0082).

CONCLUSIONS

Among U.S. postmenopausal women, a positive association of upper-body fat with risk of LEAD appeared to be attributable to traditional risk factors, especially insulin resistance. Lower-body fat was inversely associated with risk of LEAD beyond known risk factors.

Association of a healthy lifestyle index with risk of breast cancer among women with normal body mass index in the UK Biobank

BACKGROUND

A high healthy lifestyle index (HLI), a composite score based on good diet quality, low alcohol consumption, no smoking, moderate to high physical activity, and waist circumference <80cm, has been consistently associated with a reduced risk of breast cancer (BC). Recently, high levels of body fat were found to be associated with an elevated risk of BC in postmenopausal women with a normal body mass index (BMI) (18.5-<25 kg/m2). Whether the HLI is associated with BC risk in women with normal BMI is unknown.

METHODS

We studied 102,572 women aged 40-69 years with a normal BMI at enrollment into the UK Biobank cohort study. The HLI was created by assigning to each component higher scores for healthier behaviors and then summing the scores. The HLI was categorized by tertiles and age- and multivariable-adjusted hazard ratios (HRs) for the association of the HLI with BC risk by menopausal status were estimated using Cox proportional hazards models.

RESULTS

In postmenopausal women, compared to a low HLI, higher scores were associated with a reduced risk of BC (HRHLI-3rd tertile 0.76; 95% CI, 0.64-0.91). Findings were similar for premenopausal women, although they did not reach statistical significance, except when smoking status was excluded from the HLI score (HLIwithout smoking: HR3rd tertile, 0.71; 95% CI, 0.56-0.90).

CONCLUSIONS

In normal BMI postmenopausal women, a high HLI score was associated with a reduced risk of BC.

IMPACT

Following a healthy lifestyle may reduce the risk of BC among normal weight postmenopausal women.

Characterizing Trends in Lung Cancer Mortality Attributable to Airborne Environmental Carcinogens

Tracheal, bronchus, and lung (TBL) cancer is the leading cause of cancer death globally, but trends in TBL mortality attributable to tobacco, ambient particulate matter pollution (APMP), and household air pollution (HAP) were unequally distributed within global population subgroups over the last three decades. We used data from the Global Burden of Disease 2019 study to quantify the impact of sex, time, sociodemographic development index (SDI), and age for each exposure from 1990–2019. During that interval, tobacco dominated the TBL cancer mortality landscape, with its minimum global age-adjusted death rate of 16.71 deaths/100,000 (95% Uncertainty Interval (UI): 15.27–18.13) outstripping maximums of 3.85 deaths/100,000 (UI: 2.82–4.83) and 2.54 deaths/100,000 (UI: 1.69–3.54) for APMP and HAP, respectively. In 2019, tobacco male TBL death rates exceeded female rates by a factor of 4.4:1. Ratios of 1.9:1 for APMP and 2.1:1 for HAP were seen. Our analysis indicates that both-sex middle SDI and female low, low-middle, and high-middle SDI populations are suffering increasing tobacco TBL burden. Efforts producing successful global reductions in HAP-associated TBL mortality should continue, with attention to low SDI female death rate increases. Finally, except for high SDI populations, global APMP-attributable TBL cancer burden is increasing and represents a major health concern.

Molecular markers of risk of subsequent invasive breast cancer in women with ductal carcinoma in situ: protocol for a population-based cohort study

INTRODUCTION

Ductal carcinoma in situ (DCIS) of the breast is a non-obligate precursor of invasive breast cancer (IBC). Many DCIS patients are either undertreated or overtreated. The overarching goal of the study described here is to facilitate detection of patients with DCIS at risk of IBC development. Here, we propose to use risk factor data and formalin-fixed paraffin-embedded (FFPE) DCIS tissue from a large, ethnically diverse, population-based cohort of 8175 women with a first diagnosis of DCIS and followed for subsequent IBC to: identify/validate miRNA expression changes in DCIS tissue associated with risk of subsequent IBC; evaluate ipsilateral IBC risk in association with two previously identified marker sets (triple immunopositivity for p16, COX-2, Ki67; Oncotype DX Breast DCIS score); examine the association of risk factor data with IBC risk.

METHODS AND ANALYSIS

We are conducting a series of case-control studies nested within the cohort. Cases are women with DCIS who developed subsequent IBC; controls (2/case) are matched to cases on calendar year of and age at DCIS diagnosis. We project 485 cases/970 controls in the aim focused on risk factors. We estimate obtaining FFPE tissue for 320 cases/640 controls for the aim focused on miRNAs; of these, 173 cases/346 controls will be included in the aim focused on p16, COX-2 and Ki67 immunopositivity, and of the latter, 156 case-control pairs will be included in the aim focused on the Oncotype DX Breast DCIS score®. Multivariate conditional logistic regression will be used for statistical analyses.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Institutional Review Boards of Albert Einstein College of Medicine (IRB 2014-3611), Kaiser Permanente Colorado, Kaiser Permanente Hawaii, Henry Ford Health System, Mayo Clinic, Marshfield Clinic Research Institute and Hackensack Meridian Health, and from Lifespan Research Protection Office. The study results will be presented at meetings and published in peer-reviewed journals.

A Randomized Trial of Calcium Plus Vitamin D Supplementation and Risk of Ductal Carcinoma In Situ of the Breast

Background

The effect of calcium plus vitamin D (CaD) supplementation on risk of ductal carcinoma in situ (DCIS) of the breast, a nonobligate precursor of invasive ductal carcinoma, is not well understood. In this secondary analysis, we examined this association in the Women’s Health Initiative CaD trial over approximately 20 years of follow-up.

Methods

A total of 36 282 cancer-free postmenopausal women (50-79 years) were randomly assigned to daily (d) calcium (1000 mg) plus vitamin D (400 IU) supplementation or to a placebo. Personal supplementation with vitamin D (≤600 IU/d, subsequently raised to 1000 IU/d) and calcium (≤1000 mg/d) was allowed. The intervention phase (median = 7.1 years), was followed by a postintervention phase (additional 13.8 years), which included 86.0% of the surviving women. A total of 595 incident DCIS cases were ascertained. Hazard ratios (HRs) plus 95% confidence intervals (CIs) were calculated.

Results

The intervention group had a lower risk of DCIS throughout follow-up (HR = 0.82, 95% CI = 0.70 to 0.96) and during the postintervention phase (HR = 0.76, 95% CI = 0.61 to 0.94). The group that used CaD personal supplements in combination with the trial intervention had a lower risk of DCIS compared with the trial placebo group that did not use personal supplementation (HR = 0.72, 95% CI = 0.56 to 0.91).

Conclusions

CaD supplementation in postmenopausal women was associated with reduced risk of DCIS, raising the possibility that consistent use of these supplements might provide long-term benefits for the prevention of DCIS.

Low-fat dietary pattern and breast cancer mortality by metabolic syndrome components: a secondary analysis of the Women's Health Initiative (WHI) randomised trial

BACKGROUND

In the Women's Health Initiative (WHI) dietary modification (DM) randomised trial, the low-fat dietary intervention reduced deaths from breast cancer (P = 0.02). Extending these findings, secondary analysis examined dietary intervention influence on breast cancer mortality by metabolic syndrome (MS) components.

METHODS

In total, 48,835 postmenopausal women with no prior breast cancer were randomised to a low-fat dietary intervention or comparison groups. Four MS components were determined at entry in 45,833 participants: (1) high waist circumference, (2) high blood pressure, (3) high cholesterol and (4) diabetes history. Forest plots of hazard ratios (HRs) were generated with P-values for interaction between randomisation groups and MS component score. Primary outcome was death from breast cancer by metabolic syndrome score.

RESULTS

HRs and 95% confidence intervals (CI) for dietary intervention influence on death from breast cancer were with no MS components (n = 10,639), HR 1.09, 95% CI 0.63-1.87; with 1-2 MS components (n = 30,948), HR 0.80, 95% CI 0.62-1.02; with 3-4 MS components (n = 4,246), HR 0.31, 95% CI 0.14-0.69 (interaction P = 0.01).

CONCLUSIONS

While postmenopausal women with 3-4 MS components were at higher risk of death from breast cancer, those randomised to a low-fat dietary intervention more likely had reduction in this risk.

REGISTRY

ClinicalTrials.gov (NCT00000611).

Dairy foods, calcium, and risk of breast cancer overall and for subtypes defined by estrogen receptor status: a pooled analysis of 21 cohort studies

BACKGROUND

Epidemiologic studies examining the relations between dairy product and calcium intakes and breast cancer have been inconclusive, especially for tumor subtypes.

OBJECTIVE

To evaluate the associations between intakes of specific dairy products and calcium and risk of breast cancer overall and for subtypes defined by estrogen receptor (ER) status.

METHOD

We pooled the individual-level data of over 1 million women who were followed for a maximum of 8-20 years across studies. Associations were evaluated for dairy product and calcium intakes and risk of incident invasive breast cancer overall (n = 37,861 cases) and by subtypes defined by ER status. Study-specific multivariable hazard ratios (HRs) were estimated and then combined using random-effects models.

RESULTS

Overall, no clear association was observed between the consumption of specific dairy foods, dietary (from foods only) calcium, and total (from foods and supplements) calcium, and risk of overall breast cancer. Although each dairy product showed a null or very weak inverse association with risk of overall breast cancer (P, test for trend >0.05 for all), differences by ER status were suggested for yogurt and cottage/ricotta cheese with associations observed for ER-negative tumors only (pooled HR = 0.90, 95% CI: 0.83, 0.98 comparing ≥60 g/d with <1 g/d of yogurt and 0.85, 95% CI: 0.76, 0.95 comparing ≥25 g/d with <1 g/d of cottage/ricotta cheese). Dietary calcium intake was only weakly associated with breast cancer risk (pooled HR = 0.98, 95% CI: 0.97, 0.99 per 350 mg/d).

CONCLUSION

Our study shows that adult dairy or calcium consumption is unlikely to associate with a higher risk of breast cancer and that higher yogurt and cottage/ricotta cheese intakes were inversely associated with the risk of ER-negative breast cancer, a less hormonally dependent subtype with poor prognosis. Future studies on fermented dairy products, earlier life exposures, ER-negative breast cancer, and different racial/ethnic populations may further elucidate the relation.

Performance of the IBIS/Tyrer-Cuzick model of breast cancer risk by race and ethnicity in the Women's Health Initiative

BACKGROUND

The IBIS/Tyrer-Cuzick model is used clinically to guide breast cancer screening and prevention, but was developed primarily in non-Hispanic White women. Little is known about its long-term performance in a racially/ethnically diverse population.

METHODS

The Women's Health Initiative study enrolled postmenopausal women from 1993-1998. Women were included who were aged <80 years at enrollment with no prior breast cancer or mastectomy and with data required for IBIS/Tyrer-Cuzick calculation (weight; height; ages at menarche, first birth, and menopause; menopausal hormone therapy use; and family history of breast or ovarian cancer). Calibration was assessed by the ratio of observed breast cancer cases to the number expected by the IBIS/Tyrer-Cuzick model (O/E; calculated as the sum of cumulative hazards). Differential discrimination was tested for by self-reported race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic, Asian or Pacific Islander, and American Indian or Alaskan Native) using Cox regression. Exploratory analyses, including simulation of a protective single-nucleotide polymorphism (SNP), rs140068132 at 6q25, were performed.

RESULTS

During follow-up (median 18.9 years, maximum 23.4 years), 6783 breast cancer cases occurred among 90,967 women. IBIS/Tyrer-Cuzick was well calibrated overall (O/E ratio = 0.95; 95% CI, 0.93-0.97) and in most racial/ethnic groups, but overestimated risk for Hispanic women (O/E ratio = 0.75; 95% CI, 0.62-0.90). Discrimination did not differ by race/ethnicity. Exploratory simulation of the protective SNP suggested improved IBIS/Tyrer-Cuzick calibration for Hispanic women (O/E ratio = 0.80; 95% CI, 0.66-0.96).

CONCLUSIONS

The IBIS/Tyrer-Cuzick model is well calibrated for several racial/ethnic groups over 2 decades of follow-up. Studies that incorporate genetic and other risk factors, particularly among Hispanic women, are essential to improve breast cancer-risk prediction.

Circulating Levels of Testosterone, Sex Hormone Binding Globulin and Colorectal Cancer Risk: Observational and Mendelian Randomization Analyses

BACKGROUND

Epidemiologic studies evaluating associations between sex steroid hormones and colorectal cancer risk have yielded inconsistent results. To elucidate the role of circulating levels of testosterone, and sex hormone-binding globulin (SHBG) in colorectal cancer risk, we conducted observational and Mendelian randomization (MR) analyses.

METHODS

The observational analyses included 333,530 participants enrolled in the UK Biobank with testosterone and SHBG measured. HRs and 95% confidence intervals (CI) were estimated using multivariable Cox proportional hazards models. For MR analyses, genetic variants robustly associated with hormone levels were identified and their association with colorectal cancer (42,866 cases/42,752 controls) was examined using two-sample MR.

RESULTS

In the observational analysis, there was little evidence that circulating levels of total testosterone were associated with colorectal cancer risk; the MR analyses showed a greater risk for women (OR per 1-SD = 1.09; 95% CI, 1.01-1.17), although pleiotropy may have biased this result. Higher SHBG concentrations were associated with greater colorectal cancer risk for women (HR per 1-SD = 1.16; 95% CI, 1.05-1.29), but was unsupported by the MR analysis. There was little evidence of associations between free testosterone and colorectal cancer in observational and MR analyses.

CONCLUSIONS

Circulating concentrations of sex hormones are unlikely to be causally associated with colorectal cancer. Additional experimental studies are required to better understand the possible role of androgens in colorectal cancer development.

IMPACT

Our results from large-scale analyses provide little evidence for sex hormone pathways playing a causal role in colorectal cancer development.See related commentary by Hang and Shen, p. 1302.

Abstract 35: Racial disparity in localized breast cancer: Pooled analysis of NSABP trials

Background: The purpose of this study was to evaluate whether there are differences in distant recurrence rates between Black and White women with localized breast cancer who participated in NCI-sponsored clinical trials, and thus had access to state of the art oncologic care and lacked major comorbidities.

Methods: We analyzed pooled data from 10 NSABP trials including 10,364 patients with localized breast cancer treated with adjuvant chemotherapy (AC, n=8147) or neoadjuvant chemotherapy (NAC, n=2217), limited to those with self-reported race that was either Black (n=1006, 10.3%) or White (n=9358, 89.7%). AC/NAC included doxorubicin and cyclophosphamide, with or without a taxane. The association between race (Black vs. White) and distant relapse-free survival (DRFS) was analyzed in the overall population and stratified by AC or NAC use. Log rank tests were used to test for differences in DRFS. Multivariate Cox regression was performed to estimate risk of distant recurrence adjusted for other prognostic covariates including age (continuous), tumor size (&gt; 2 cm vs. &lt; 2 cm), ER expression (positive vs. negative), and nodal status (pathologically positive for AC cohort or clinically positive for NAC cohort vs. negative).

Results: In the AC cohort, 7,419 (91%) patients were White and 728 (9%) Black. In the NAC cohort, 1,939 (88%) were White and 278 (12%) Black. Black race was associated with an inferior DRFS in the combined AC/NAC cohort (Logrank p&lt;.0001), and in both the AC and NAC cohorts (Logrank p=0.0008 and p=0.01, respectively). After adjustment for other covariates in multivariate analysis, Black race remained significantly associated with an inferior DRFS in the combined AC/NAC cohort (HR 1.17, [95% CI 1.05-1.31], p=0.004), with similar trends noted in the AC (HR 1.17 [95% CI 1.02-1.33], p=0.03) and NAC cohort (HR 1.21 [95% CI 0.98-1.45], p=0.08). When the AC cohort was analyzed by ER status, Black race was associated with worse DRFS in ER-positive disease (HR 1.32 [95% CI 1.06-1.63], p=0.02), but not ER-negative disease (HR 1.06, [95% CI 0.87-1.30], p=0.57), although there was no statistically significant interaction with ER status (p=0.15). In the NAC cohort, Black women had a higher pathologic complete response (pCR) rate (22% vs 17%, Chi-squared test p=0.03). Black race was associated with a significantly worse DRFS in patients who did not achieve pCR (HR 1.34 [95% CI 1.06-1.63], p=0.01), but not in those who had a pCR (HR 0.89 [95% CI 0.49, 1.61], p=0.71).

Conclusion: We observed that Black women with localized breast cancer had higher distant recurrence rates than White women. This and other reports suggest that factors other than social determinants of health may be contributing to racial disparities in breast cancer outcome/progression, most notably in ER-positive disease and patients with residual disease after NAC. Future research is needed to help delineate the biological differences that contribute to these observations.

Citation Format: Gina Kim, Jessica M. Pastoriza, Jiyue Qin, Juan Lin, George S. Karagiannis, John S. Condeelis, Greg Yothers, Thomas B. Julian, Stewart J. Anderson, David Entenberg, Thomas E. Rohan, Joseph A. Sparano, Xiaonan Xue, Maja H. Oktay. Racial disparity in localized breast cancer: Pooled analysis of NSABP trials [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 35.

Low-Fat Dietary Modification and Risk of Ductal Carcinoma In Situ of the Breast in the Women's Health Initiative Dietary Modification Trial

BACKGROUND

Results of observational studies of the association between dietary fat and risk of invasive breast cancer have been inconsistent. In the Women's Health Initiative dietary modification (DM) randomized trial designed to lower fat intake, the intervention was not associated with a statistically significant reduction of overall breast cancer risk. However, the DM association with risk of ductal carcinoma in situ (DCIS) of the breast, a putative breast cancer precursor, has not been reported.

METHODS

A total of 48,835 postmenopausal women, ages 50-79 years at enrollment, with no breast cancer history and ≥32% of total energy intake from fat, were randomly assigned either to a dietary intervention (n = 19,541) designed to reduce total fat intake to 20% of energy and to increase vegetable, fruit, and grain consumption, or to a comparison group (n = 29,294). Cox proportional hazards models were used to estimate HRs and 95% confidence intervals for the association between the intervention and DCIS risk.

RESULTS

During 18.7 years (median) cumulative follow-up, including intervention (∼8.7 years) and post-intervention phases (∼13.0 years), 817 DCIS cases were ascertained. No evidence of an association between the DM intervention and DCIS risk was observed overall, or by trial phase (intervention and post-intervention). Similarly, no associations were found in subgroups defined by potential risk factors for DCIS.

CONCLUSIONS

DM aiming to reduce fat intake was not associated with altered risk of DCIS.

IMPACT

These results do not provide evidence of an association between dietary fat reduction and the risk of DCIS among postmenopausal women.