Moderate physical activity and breast cancer risk: the effect of menopausal status

Sugar-Sweetened Beverages Consumption and Breast Cancer in Premenopausal and Postmenopausal Women

BACKGROUND

The consumption of sugar-sweetened beverages (SSB), of which Mexico is a large consumer, has been associated with the risk of breast cancer. We assessed the association between SSBs consumption and breast cancer risk in pre- and postmenopausal women.

METHODS

We performed a multicenter population-based case-control study in Mexico City, Monterrey, and Veracruz. We recruited 1,000 cases and 1,074 controls; all participants were pre- or postmenopausal women between 35 and 69 years of age. Diet before symptoms onset was assessed using a food frequency questionnaire. We conducted a multivariable-adjusted conditional logistic regression analysis stratified by menopausal status.

RESULTS

For premenopausal women, after adjusting for matching characteristics, total energy intake and all potential confounders, the odds of having breast cancer in women who drank one or more SSBs servings per day showed 1.78 times the odds of those who drank one or fewer SSBs servings per month [OR = 1.78; 95% confidence interval (CI), 1.06-3.01]. For postmenopausal women, the corresponding model was not statistically significant (OR = 1.38, 95% CI, 0.84-2.25). We also observed higher consumption of SSBs among pre- than in postmenopausal women (23.3% and 17.4%, respectively among controls in the highest consumption category (≥1 per day).

CONCLUSIONS

Our results suggest that SSBs consumption increases the risk of developing breast cancer, particularly in premenopausal women.

IMPACT

Given the consumption of SSBs, of which Mexico is a large consumer, these results can support public policies to discourage the consumption of SSBs.

Exercise as a Promising Agent against Cancer: Evaluating Its Anti-Cancer Molecular Mechanisms

BACKGROUND

Cancer cases are continuously increasing, while the prevalence rates of physical inactivity are also continuously increasing. Physical inactivity is a causative factor in non-communicable diseases, including cancer. However, the potential beneficial effects of exercise on cancer treatment have not received much attention so far. The aim of this study was to highlight the relationship between cancer and exercise on a molecular basis.

METHODS

Comprehensive and in-depth research was conducted in the most accurate scientific databases by using relevant and effective keywords.

RESULTS

The mechanisms by which exercise may reduce cancer risk and/or progression may include the metabolic profile of hormones, systemic inflammation reduction, insulin sensitivity increase, antioxidant capacity augmentation, the boost to the immune system, and the direct effect on the tumor. There is currently substantial evidence that the effect of exercise may predict a stronger association with cancer and could supplementarily be embedded in cancer clinical practice to improve disease progression and prognosis.

CONCLUSION

The field of this study requires interconnecting the overall knowledge of exercise physiology with cancer biology and cancer clinical oncology to provide the basis for personalized targeting strategies that can be merged with training as a component of a holistic co-treatment approach to optimize cancer healthcare.

Native American ancestry and breast cancer risk in Colombian and Mexican women: ruling out potential confounding through ancestry-informative markers

BACKGROUND

Latin American and Hispanic women are less likely to develop breast cancer (BC) than women of European descent. Observational studies have found an inverse relationship between the individual proportion of Native American ancestry and BC risk. Here, we use ancestry-informative markers to rule out potential confounding of this relationship, estimating the confounder-free effect of Native American ancestry on BC risk.

METHODS AND STUDY POPULATION

We used the informativeness for assignment measure to select robust instrumental variables for the individual proportion of Native American ancestry. We then conducted separate Mendelian randomization (MR) analyses based on 1401 Colombian women, most of them from the central Andean regions of Cundinamarca and Huila, and 1366 Mexican women from Mexico City, Monterrey and Veracruz, supplemented by sensitivity and stratified analyses.

RESULTS

The proportion of Colombian Native American ancestry showed a putatively causal protective effect on BC risk (inverse variance-weighted odds ratio [OR] = 0.974 per 1% increase in ancestry proportion, 95% confidence interval [CI] 0.970-0.978, p = 3.1 × 10-40). The corresponding OR for Mexican Native American ancestry was 0.988 (95% CI 0.987-0.990, p = 1.4 × 10-44). Stratified analyses revealed a stronger association between Native American ancestry and familial BC (Colombian women: OR = 0.958, 95% CI 0.952-0.964; Mexican women: OR = 0.973, 95% CI 0.969-0.978), and stronger protective effects on oestrogen receptor (ER)-positive BC than on ER-negative and triple-negative BC.

CONCLUSIONS

The present results point to an unconfounded protective effect of Native American ancestry on BC risk in both Colombian and Mexican women which appears to be stronger for familial and ER-positive BC. These findings provide a rationale for personalised prevention programmes that take genetic ancestry into account, as well as for future admixture mapping studies.

Disparities in breast cancer mortality among Latin American women: trends and predictions for 2030

BACKGROUND

Breast cancer is among the leading cause of cancer-related mortality among Latin American and Caribbean (LAC) women, but a comprehensive and updated analysis of mortality trends is lacking. The objective of this study was to determine the breast cancer mortality rates between 1997 and 2017 for LAC countries and predict mortality until 2030.

METHODS

We retrieved breast cancer deaths across 17 LAC countries from the World Health Organization mortality database. Age-standardized mortality rates per 100,000 women-years were estimated. Mortality trends were evaluated with Joinpoint regression analyses by country and age group (all ages, < 50 years, and ≥ 50 years). By 2030, we predict number of deaths, mortality rates, changes in population structure and size, and the risk of death from breast cancer.

RESULTS

Argentina, Uruguay, and Venezuela reported the highest mortality rates throughout the study period. Guatemala, El Salvador, and Nicaragua reported the largest increases (from 2.4 to 2.8% annually), whereas Argentina, Chile, and Uruguay reported downward trends (from - 1.0 to - 1.6% annually). In women < 50y, six countries presented downward trends and five countries showed increasing trends. In women ≥ 50y, three countries had decreased trends and ten showed increased trends. In 2030, increases in mortality are expected in the LAC region, mainly in Guatemala (+ 63.0%), Nicaragua (+ 47.3), El Salvador (+ 46.2%), Ecuador (+ 38.5%) and Venezuela (+ 29.9%).

CONCLUSION

Our findings suggest considerable differences in breast cancer mortality across LAC countries by age group. To achieve the 2030 sustainable developmental goals, LAC countries should implement public health strategies to reduce mortality by breast cancer.

Single-cell sequencing of immune cells after marathon and symptom-limited cardiopulmonary exercise

Vigorous-intensity leisure-time physical activity, such as marathon, has become increasingly popular, but its effect on immune functions and health is poorly understood. Here, we performed scRNA-seq analysis of peripheral blood mononuclear cells (PBMCs) after a bout of symptom-limited cardiopulmonary exercise (CPX) test or marathon. Time-series single-cell analysis revealed the detailed series of landscapes of immune cells in response to short and long vigorous-intensity activities. Reduction of effective T cells was observed with the cell migration and motility pathways enriched in circulation following marathon. Baseline values of PBMCs abundance were reached around 1 h after CPX and 24 h following marathon, but longer time was required for expression recovery of cytotoxicity genes. The ratio of effector/naive T cells was found to change uniformly among the participants and could serve as a better indicator for exercise intensity than the CD4+/CD8+ T cell ratio. Moreover, we identified time-dependent monocyte state transitions after marathon.

Breast cancer subtype and clinical characteristics in women from Peru

Introduction

Breast cancer is a heterogeneous disease, and the distribution of the different subtypes varies by race/ethnic category in the United States and by country. Established breast cancer-associated factors impact subtype-specific risk; however, these included limited or no representation of Latin American diversity. To address this gap in knowledge, we report a description of demographic, reproductive, and lifestyle breast cancer-associated factors by age at diagnosis and disease subtype for The Peruvian Genetics and Genomics of Breast Cancer (PEGEN-BC) study.

Methods

The PEGEN-BC study is a hospital-based breast cancer cohort that includes 1943 patients diagnosed at the Instituto Nacional de Enfermedades Neoplásicas in Lima, Peru. Demographic and reproductive information, as well as lifestyle exposures, were collected with a questionnaire. Clinical data, including tumor Hormone Receptor (HR) status and Human Epidermal Growth Factor Receptor 2 (HER2) status, were abstracted from electronic medical records. Differences in proportions and mean values were tested using Chi-squared and one-way ANOVA tests, respectively. Multinomial logistic regression models were used for multivariate association analyses.

Results

The distribution of subtypes was 52% HR+HER2-, 19% HR+HER2+, 16% HR-HER2-, and 13% HR-HER2+. Indigenous American (IA) genetic ancestry was higher, and height was lower among individuals with the HR-HER2+ subtype (80% IA vs. 76% overall, p=0.007; 152 cm vs. 153 cm overall, p=0.032, respectively). In multivariate models, IA ancestry was associated with HR-HER2+ subtype (OR=1.38,95%CI=1.06-1.79, p=0.017) and parous women showed increased risk for HR-HER2+ (OR=2.7,95%CI=1.5-4.8, p<0.001) and HR-HER2- tumors (OR=2.4,95%CI=1.5-4.0, p<0.001) compared to nulliparous women. Multiple patient and tumor characteristics differed by age at diagnosis (<50 vs. >=50), including ancestry, region of residence, family history, height, BMI, breastfeeding, parity, and stage at diagnosis (p<0.02 for all variables).

Discussion

The characteristics of the PEGEN-BC study participants do not suggest heterogeneity by tumor subtype except for IA genetic ancestry proportion, which has been previously reported. Differences by age at diagnosis were apparent and concordant with what is known about pre- and post-menopausal-specific disease risk factors. Additional studies in Peru should be developed to further understand the main contributors to the specific age of onset and molecular disease subtypes in this population and develop population-appropriate predictive models for prevention.

Whole exome sequencing and replication for breast cancer among Hispanic/Latino women identifies FANCM as a susceptibility gene for estrogen-receptor-negative breast cancer

Introduction

Breast cancer (BC) is one of the most common cancers globally. Genetic testing can facilitate screening and risk-reducing recommendations, and inform use of targeted treatments. However, genes included in testing panels are from studies of European-ancestry participants. We sequenced Hispanic/Latina (H/L) women to identify BC susceptibility genes.

Methods

We conducted a pooled BC case-control analysis in H/L women from the San Francisco Bay area, Los Angeles County, and Mexico (4,178 cases and 4,344 controls). Whole exome sequencing was conducted on 1,043 cases and 1,188 controls and a targeted 857-gene panel on the remaining samples. Using ancestry-adjusted SKAT-O analyses, we tested the association of loss of function (LoF) variants with overall, estrogen receptor (ER)-positive, and ER-negative BC risk. We calculated odds ratios (OR) for BC using ancestry-adjusted logistic regression models. We also tested the association of single variants with BC risk.

Results

We saw a strong association of LoF variants in FANCM with ER-negative BC (p=4.1×10-7, OR [CI]: 6.7 [2.9-15.6]) and a nominal association with overall BC risk. Among known susceptibility genes, BRCA1 (p=2.3×10-10, OR [CI]: 24.9 [6.1-102.5]), BRCA2 (p=8.4×10-10, OR [CI]: 7.0 [3.5-14.0]), and PALB2 (p=1.8×10-8, OR [CI]: 6.5 [3.2-13.1]) were strongly associated with BC. There were nominally significant associations with CHEK2, RAD51D, and TP53.

Conclusion

In H/L women, LoF variants in FANCM were strongly associated with ER-negative breast cancer risk. It previously was proposed as a possible susceptibility gene for ER-negative BC, but is not routinely tested in clinical practice. Our results demonstrate that FANCM should be added to BC gene panels.

Factors associated with breast disorders detected by clinical breast examination during pregnancy and six months postpartum in Ibadan, South-western Nigeria

Background

Breast disorders (BD) during pregnancy and postpartum cause anxiety and reduce women's quality of life. The study examined BD risk factors during pregnancy and six months after delivery.

Methods

Women attending antenatal clinics at 26 weeks gestation were recruited. 1248 pregnant women were followed six months postpartum. During recruitment, a validated questionnaire was used to collect participant characteristics and risk factors. Palpable lumps, inflammation, persistent pain, and abnormal nipple discharge were classified breast disorders. Statistical analysis used multiple logistic and cox regression models at p<0.05.

Results

Women with benign breast disease were more likely to develop BD (aOR = 2.63, 95% CI = 1.50-4.88). One pregnancy increases the risk of BD more than three times (aOR=0.52, 95%CI: 0.29-0.95). History of breast trauma (aHR=3.59, 95%CI: 1.40-9.17) and 3 miscarriages vs. none (aHR=2.23, 95%CI: 1.04-4.23) were also risk factors for BD. The second quartile of physical activity was associated with a lower risk of BD (aHR=0.35, 95%CI: 0.15-0.78).

Conclusion

Women with breast trauma and miscarriage are more likely to develop breast disorders during pregnancy and six months after delivery. Our findings highlight the need for additional longitudinal research to validate these findings and plans for prevention and control. Keywords: Breast disorders, pregnancy, postpartum, predictors, longitudinal study.

The effect of the number of biopsies on the delay in the time from the delivery of mammography results to breast cancer histopathological diagnosis

PURPOSE

The delay in the time (in calendar days) from the delivery of mammography results to histopathological breast cancer (BC) diagnosis could be associated with more advanced clinical stages, a worse prognosis and higher mortality. Therefore, we assessed the association between the number of biopsies and the delay in the time (in calendar days) from the delivery of mammography results to histopathological BC.

METHODS

A survey was performed on 563 women aged between 35 and 69 years with histopathologically confirmed BC who attended 11 Mexican hospitals.

RESULTS

After adjusting for potential confounders, the odds of having a delay in the time (in calendar days) from the delivery of mammography results to histopathological BC diagnosis (≥ 60 days) among women with ≥ 3 biopsies were 2.99 times the odds of those who had only one biopsy (95% CI 1.35, 6.63).

CONCLUSION

The number of biopsies should be considered as a predictor of the time delay between the delivery of the mammography result and the diagnostic result.

Energy homeostasis genes modify the association between serum concentrations of IGF-1 and IGFBP-3 and breast cancer risk

Breast cancer is a multifactorial disease in which the interplay among multiple risk factors remains unclear. Energy homeostasis genes play an important role in carcinogenesis and their interactions with the serum concentrations of IGF-1 and IGFBP-3 on the risk of breast cancer have not yet been investigated. The aim of this study was to assess the modifying effect of the genetic variation in some energy homeostasis genes on the association of serum concentrations of IGF-1 and IGFBP-3 with breast cancer risk. We analyzed 78 SNPs from 10 energy homeostasis genes in premenopausal women from the 4-Corner’s Breast Cancer Study (61 cases and 155 controls) and the Mexico Breast Cancer Study (204 cases and 282 controls). After data harmonization, 71 SNPs in HWE were included for interaction analysis. Two SNPs in two genes (MBOAT rs13272159 and NPY rs16131) showed an effect modification on the association between IGF-1 serum concentration and breast cancer risk (P_interaction < 0.05, adjusted P_interaction < 0.20). In addition, five SNPs in three genes (ADIPOQ rs182052, rs822391 and rs7649121, CARTPT rs3846659, and LEPR rs12059300) had an effect modification on the association between IGFBP-3 serum concentration and breast cancer risk (P_interaction < 0.05, adjusted P_interaction < 0.20). Our findings showed that variants of energy homeostasis genes modified the association between the IGF-1 or IGFBP-3 serum concentration and breast cancer risk in premenopausal women. These findings contribute to a better understanding of this multifactorial pathology.

Reliability and validity of the Mexican teachers' physical activity questionnaire (MTPAQ) in a subsample of female Mexican teachers

BACKGROUND

Reliable and valid instruments are needed to estimate physical activity levels. The purposes of this study were to estimate the reliability and validity of the Physical Activity Questionnaire (MTPAQ) in a subsample of the Mexican Teachers Cohort study.

METHODS

We completed telephone interviews and clinical examinations of 82 teachers. Two MTPAQ, five International Physical Activity Questionnaire (IPAQ)-long form, and two accelerometer (AC) measures were used to determine physical activity levels throughout 24 months. Moderate and walking physical activity (MWPA min/week), vigorous physical activity (VPA min/week), and moderate-to-vigorous physical activity minutes per week (MVPA min/week) were estimated for each instrument. Pearson, Intra-class correlations and deattenuated adjustments were used to determine the reliability and validity of MTPAQ.

RESULTS

MWPA and MVPA min/week of MTPAQs were moderately correlated (r ≥ 0.54) to min/week of IPAQ-long form. MWPA and MVPA min/week average MTPAQ and MTPAQ1 and average AC, AC1 and AC2 were fairly correlated (r ≥ 0.20). A higher correlation was observed when correlation coefficients were attenuated (r ≥ 0.32).

CONCLUSIONS

MTPAQ1 is a reliable and valid tool to measure physical activity levels.

Biomarkers of mammographic density in premenopausal women

BACKGROUND

While mammographic density is one of the strongest risk factors for breast cancer, little is known about its determinants, especially in young women. We applied targeted metabolomics to identify circulating metabolites specifically associated with mammographic density in premenopausal women. Then, we aimed to identify potential correlates of these biomarkers to guide future research on potential modifiable determinants of mammographic density.

METHODS

A total of 132 metabolites (acylcarnitines, amino acids, biogenic amines, glycerophospholipids, sphingolipids, hexose) were measured by tandem liquid chromatography/mass spectrometry in plasma samples from 573 premenopausal participants in the Mexican Teachers' Cohort. Associations between metabolites and percent mammographic density were assessed using linear regression models, adjusting for breast cancer risk factors and accounting for multiple tests. Mean concentrations of metabolites associated with percent mammographic density were estimated across levels of several lifestyle and metabolic factors.

RESULTS

Sphingomyelin (SM) C16:1 and phosphatidylcholine (PC) ae C30:2 were inversely associated with percent mammographic density after correction for multiple tests. Linear trends with percent mammographic density were observed for SM C16:1 only in women with body mass index (BMI) below the median (27.4) and for PC ae C30:2 in women with a BMI over the median. SM C16:1 and PC ae C30:2 concentrations were positively associated with cholesterol (total and HDL) and inversely associated with number of metabolic syndrome components.

CONCLUSIONS

We identified new biomarkers associated with mammographic density in young women. The association of these biomarkers with mammographic density and metabolic parameters may provide new perspectives to support future preventive actions for breast cancer.

A Polygenic Risk Score for Breast Cancer in US Latinas and Latin American Women

Background

More than 180 single nucleotide polymorphisms (SNPs) associated with breast cancer susceptibility have been identified; these SNPs can be combined into polygenic risk scores (PRS) to predict breast cancer risk. Because most SNPs were identified in predominantly European populations, little is known about the performance of PRS in non-Europeans. We tested the performance of a 180-SNP PRS in Latinas, a large ethnic group with variable levels of Indigenous American, European, and African ancestry.

Methods

We conducted a pooled case-control analysis of US Latinas and Latin American women (4658 cases and 7622 controls). We constructed a 180-SNP PRS consisting of SNPs associated with breast cancer risk (P < 5 × 10^–8). We evaluated the association between the PRS and breast cancer risk using multivariable logistic regression, and assessed discrimination using an area under the receiver operating characteristic curve. We also assessed PRS performance across quartiles of Indigenous American genetic ancestry. All statistical tests were two-sided.

Results

Of 180 SNPs tested, 142 showed directionally consistent associations compared with European populations, and 39 were nominally statistically significant (P < .05). The PRS was associated with breast cancer risk, with an odds ratio per SD increment of 1.58 (95% confidence interval [CI = 1.52 to 1.64) and an area under the receiver operating characteristic curve of 0.63 (95% CI = 0.62 to 0.64). The discrimination of the PRS was similar between the top and bottom quartiles of Indigenous American ancestry.

Conclusions

The 180-SNP PRS predicts breast cancer risk in Latinas, with similar performance as reported for Europeans. The performance of the PRS did not vary substantially according to Indigenous American ancestry.

Association of physical activity, body mass index and reproductive history with breast cancer by menopausal status in Iranian women

BACKGROUND

The incidence rate of breast cancer (BC) is increasing in low- and middle-income countries (LMICs), including Iran. We investigated the association between BC risk and physical activity (PA), body mass index (BMI), and reproductive history among Iranian women.

METHODS

We conducted a large hospital-based case-control study and compared 958 BC cases with 967 controls at the Cancer Institute of Iran during 2011-2016. We used multiple logistic regression models and adjusted for potential confounders to estimate odds ratios (ORs) and 95% confidence intervals (95%CIs) for the associations between BC and different risk factors, including low physical activity.

RESULTS

Women with high levels of physical activity had a lower risk of BC compared to those who were inactive (OR = 0.55, 95%CI: 0.41, 0.75). In premenopausal women, the association was observed only in normal-weight women (OR = 0.31, 95%CI: 0.13, 0.75), while it was limited to obese women in the postmenopausal group (OR = 0.29, 95%CI: 0.12, 0.66). We found a high risk of postmenopausal BC among overweight (OR = 1.69; 95%CI: 1.01, 2.81) and obese women (OR = 1.9; 95%CI: 1.14, 3.14) compared to women with a normal BMI. We observed an inverse association among postmenopausal women who had between three and five children (OR = 0.31, 95%CI 0.14, 0.64) and more than six children (OR = 0.21, 95%CI 0.12, 0.42) compared to nulliparous women.

CONCLUSIONS

Low levels of physical activity, low parity, and being overweight or obese were major risk factors for BC. For the first time, we report a strong association between physical activity and BC risk in Iranian women.

Synergistic action of folate intake and testosterone associated with breast cancer risk

The amount of irreparable DNA damage is a function of the rate of cell division, and the association between sex hormones and the risk of breast cancer has been explained by an increase in cell division. Folate intake insufficiency leads to disturbances in DNA replication and DNA repair. We hypothesized that folate intake insufficiency and high serum concentrations of sex hormones act synergistically on the risk of breast cancer. The aim of this study was to investigate the interaction between sex hormones (exposure of interest A) and dietary folate intake (exposure of interest B) on the risk of breast cancer. We included 342 breast cancer primary postmenopausal cases and 294 controls obtained from a large population-based case-control study. Multiple conditional logistic regression models were used for the analysis and interactions were tested. The joint effect of the lowest dietary folate intake (T1 < 259.40 mg/d) and the highest serum concentration of testosterone (T3 ≥ 0.410 on the risk of breast cancer was odds ratio = 9.18 (95% confidence interval 2.56-32.88) when compared to the lowest-risk category, namely, the group of women with the highest dietary folate intake (T3 > 381.29 mg/d) and the lowest serum concentration of testosterone (T1 ≤ 0.25 pg/mL). There were some indications that the estimated join effect was greater than the product of the estimated effects alone (P = .001). These findings have important public health implications with respect to reducing the risk of the most frequent cancer in women worldwide.

A Pooled Analysis of Breastfeeding and Breast Cancer Risk by Hormone Receptor Status in Parous Hispanic Women

BACKGROUND

Data on breastfeeding and breast cancer risk are sparse and inconsistent for Hispanic women.

METHODS

Pooling data for nearly 6,000 parous Hispanic women from four population-based studies conducted between 1995 and 2007 in the United States and Mexico, we examined the association of breastfeeding with risk of breast cancer overall and subtypes defined by estrogen receptor (ER) and progesterone receptor (PR) status, and the joint effects of breastfeeding, parity, and age at first birth. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression.

RESULTS

Among parous Hispanic women, older age at first birth was associated with increased breast cancer risk, whereas parity was associated with reduced risk. These associations were found for hormone receptor positive (HR+) breast cancer only and limited to premenopausal women. Age at first birth and parity were not associated with risk of ER- and PR- breast cancer. Increasing duration of breastfeeding was associated with decreasing breast cancer risk (≥25 vs. 0 months: OR = 0.73; 95% CI = 0.60, 0.89; Ptrend = 0.03), with no heterogeneity by menopausal status or subtype. At each parity level, breastfeeding further reduced HR+ breast cancer risk. Additionally, breastfeeding attenuated the increase in risk of HR+ breast cancer associated with older age at first birth.

CONCLUSIONS

Our findings suggest that breastfeeding is associated with reduced risk of both HR+ and ER- and PR- breast cancer among Hispanic women, as reported for other populations, and may attenuate the increased risk in women with a first pregnancy at older ages.

Association of a Priori-Defined Dietary Patterns with Anthropometric Measurements: A Cross-Sectional Study in Mexican Women

This cross-sectional study aimed to evaluate associations between a priori defined dietary patterns and anthropometric measures in Mexican women. A total of 1062 women aged 35 to 69 years old from the control participants of the CAMA (Cancer de Mama) study, a multi-center population-based case-control study on breast cancer conducted in Mexico, were interviewed and dietary intakes were assessed using questionnaires. The following indices were derived from these data: Dietary Approaches to Stop Hypertension (DASH) score, the Healthy Eating Index (HEI), the Mediterranean Diet Score (aMED), the Diet Quality Index (DQI), glycemic index (GI) and glycemic load (GL). Adjusting for age, center, educational level, physical activity and energy intake, a high GI was positively associated with a higher body mass index (BMI) and waist circumference (WC). Higher adherence to aMED was associated with lower WC and waist-to-hip ratio (WHR) but no significant association was observed with other a priori dietary patterns. In this population of Mexican women, higher adherence to Mediterranean diet was associated with lower WC but other a priori dietary scores appeared to be of limited value in exploring the association between diet and anthropometric measures.

Thyroid hormones and breast cancer association according to menopausal status and body mass index

BACKGROUND

Thyroxine (T4) has been positively associated with tumor cell proliferation, while the effect of triiodothyronine (T3) on cell proliferation has not been well-established because it differs according to the type of cell line used. In Mexico, it has been reported that 14.5% of adult women have some type of thyroid dysfunction and abnormalities in thyroid function tests have been observed in a variety of non-thyroidal illnesses, including breast cancer (BC). These abnormalities might change with body mass index (BMI) because thyroid hormones are involved in the regulation of various metabolic pathways and probably by menopausal status because obesity has been negatively associated with BC in premenopausal women and has been positively associated with BC in postmenopausal women.

METHODS

To assess the association between serum thyroid hormone concentration (T4 and T3) and BC and the influence of obesity as an effect modifier of this relationship in premenopausal and postmenopausal women, we measured serum thyroid hormone and thyroid antibody levels in 682 patients with incident breast cancer (cases) and 731 controls, who participated in a population-based case-control study performed from 2004 to 2007 in three states of Mexico. We tested the association of total T4 (TT4) and total T3 (TT3) stratifying by menopausal status and body mass index (BMI), and adjusted for other health and demographic risk factors using logistic regressions models.

RESULTS

Higher serum total T4 (TT4) concentrations were associated with BC in both premenopausal (odds ratio (OR) per standard deviation = 5.98, 95% CI 3.01-11.90) and postmenopausal women (OR per standard deviation = 2.81, 95% CI 2.17-3.65). In premenopausal women, the effect of TT4 decreased as BMI increased while the opposite was observed in postmenopausal women. The significance of the effect modification was marginal (p = 0.059) in postmenopausal women and was not significant in premenopausal women (p = 0.22). Lower TT3 concentrations were associated with BC in both premenopausal and postmenopausal women and no effect modification was observed.

CONCLUSIONS

There is a strong association between BC and serum concentrations of TT3 and TT4; this needs to be further investigated to understand why it happens and how important it is to consider these alterations in treatment.

Circulating leptin and adiponectin, and breast density in premenopausal Mexican women: the Mexican Teachers' Cohort

PURPOSE

Leptin and adiponectin are produced by the adipose tissue. Mammographic density (MD) is one of the strongest predictors of breast cancer (BC) and is highly influenced by adiposity. How the interplay between MD, obesity, and obesity-related biomarkers influences BC risk, however, is still unknown, especially in premenopausal women, where adiposity seems to be protective for BC. The aim of the present study was to explore the association between circulating leptin, adiponectin, and their ratio, with MD in Mexican premenopausal women who are part of the large Mexican Teachers' Cohort (MTC).

METHODS

A subsample of 2,084 women from the MTC participated in a clinical evaluation. Of them, 574 premenopausal women were randomly selected, from four MD strata. Serum leptin and adiponectin concentrations were measured by immunoassays. Multivariate regression analyses were performed to compare means of MD by quartiles of adipokines and their ratio.

RESULTS

High leptin and leptin/adiponectin ratio levels were significantly associated with lower percentage MD and higher absolute and non-absolute dense tissue areas. High adiponectin levels were significantly associated with lower absolute dense and non-dense tissue areas, but not with percentage MD. After adjustment for BMI, only the associations between percentage MD and absolute non-dense tissue area with leptin remained statistically significant.

CONCLUSIONS

Leptin, adiponectin, and their ratio were associated with MD; however, only the positive association with leptin seemed to be independent from overall obesity.

Association between serum phospholipid fatty acid levels and adiposity in Mexican women

Fatty acids (FAs) have been postulated to impact adiposity, but few epidemiological studies addressing this hypothesis have been conducted. This study investigated the association between serum phospholipid FAs (S-PLFAs) and indicators of obesity. BMI and waist-to-hip ratio (WHR) were collected from 372 healthy Mexican women included as controls in a case-control study. S-PLFA percentages were determined through gas chromatography. Desaturation indices, SCD-16, SCD-18, FA desaturase (FADS)1, and FADS2, biomarkers of endogenous metabolism, were proxied respectively as 16:1n-7/16:0, 18:1n-9/18:0, 20:4n-6/20:3n-6, and 22:6n-3/20:5n-3. Multiple linear regressions adjusted for relevant confounders and corrected for multiple testing were conducted to determine the association between S-PLFA, desaturation indices, and indicators of adiposity. SCD-16 (β = 0.034, P = 0.001, q = 0.014), palmitoleic acid (β = 0.031, P = 0.001, q = 0.014), and dihomo-γ-linolenic acid (β = 0.043, P = 0.000, q = 0.0002) were positively associated with BMI. Total n-6 PUFAs (β = 1.497, P = 0.047, q = 0.22) and the ratio of n-6/n-3 PUFAs (β = 0.034, P = 0.040, q = 0.19) were positively associated with WHR, while odd-chain FAs (pentadecanoic and heptadecanoic acid) showed negative associations with all the adiposity indicators. In conclusion, increased endogenous synthesis of palmitoleic acid and a high n-6/n-3 ratio are associated with increased adiposity, while odd-chain FAs are associated with decreased adiposity. Further studies are needed to determine the potential causality behind these associations.

The Interaction between Genetic Ancestry and Breast Cancer Risk Factors among Hispanic Women: The Breast Cancer Health Disparities Study

Background: Hispanic women have lower breast cancer incidence rates than non-Hispanic white (NHW) women. To what extent genetic versus nongenetic factors account for this difference is unknown.Methods: Using logistic regression, we evaluated the interactive influences of established risk factors and ethnicity (self-identified and identified by ancestral informative markers) on breast cancer risk among 2,326 Hispanic and 1,854 NHW postmenopausal women from the United States and Mexico in the Breast Cancer Health Disparities Study.Results: The inverse association between the percentage of Native American (NA) ancestry and breast cancer risk was only slightly attenuated after adjusting for known risk factors [lowest versus highest quartile: odds ratio (OR) =1.39, 95% confidence interval (CI) = 1.00-1.92 among U.S. Hispanics; OR = 1.92 (95% CI, 1.29-2.86) among Mexican women]. The prevalence of several risk factors, as well as the associations with certain factors and breast cancer risk, differed according to genetic admixture. For example, higher body mass index (BMI) was associated with reduced risk among women with lower NA ancestry only [BMI <25 versus >30: OR = 0.65 (95% CI, 0.44-0.98) among U.S. Hispanics; OR = 0.53 (95% CI, 0.29-0.97) among Mexicans]. The average number of risk factors among cases was inversely related to the percentage of NA ancestry.Conclusions: The lower NA ancestry groups were more likely to have the established risk factors, with the exception of BMI. Although the majority of factors were associated with risk in the expected directions among all women, BMI had an inverse association among Hispanics with lower NA ancestry.Impact: These data suggest that the established risk factors are less relevant for breast cancer development among women with more NA ancestry. Cancer Epidemiol Biomarkers Prev; 26(5); 692-701. ©2016 AACR.

Female breast cancer in Central and South America

RATIONALE AND OBJECTIVE

The burden of breast cancer has increased worldwide. Breast cancer mortality has been increasing in Central and South America (CSA) in the last few decades. We describe the current burden of breast cancer in CSA and review the current status of disease control.

METHODS

We obtained regional- and national-level incidence data from 48 population-based cancer registries in 13 countries and cancer deaths from the WHO mortality database for 18 countries. We estimated world population age-standardized incidence and mortality rates per 100,000 person-years for 2003-2007 and the estimated annual percentage change to describe time trends.

RESULTS

In the most recent 5-year period, Argentina, Brazil, and Uruguay had the highest incidence rates (67.7-71.9) and Bolivia and El Salvador had the lowest (7.9-12.7). For most countries, mortality rates were ≤12.3, except in Uruguay, Argentina and Cuba (14.9-20.5). Age-specific rates increased after the age of 40-50 years and reached a maximum after age 65 years (mean age at diagnosis 56-62 years). Most countries have developed national screening guidelines; however, there is limited capacity for screening.

CONCLUSION

The geographic variation of breast cancer rates may be explained by differences in the prevalence of reproductive patterns, lifestyle factors, early detection, and healthcare access. Extending early-detection programs is challenging because of inequalities in healthcare access and coverage, limited funding, and inadequate infrastructure, and thus it may not be feasible. Given the current status of breast cancer in CSA, data generated by population-based cancer registries is urgently needed for effective planning for cancer control.

Serum 25-Hydroxyvitamin D3 and Mammography Density among Mexican Women

Low circulating levels of vitamin D and high mammographic density (MD) have been associated with higher risk of breast cancer. Although some evidence suggested an inverse association between circulating vitamin D and MD, no studies have investigated this association among Mexican women. We examined whether serum 25-hydroxyvitamin D3 [25(OH)D3] levels were associated with MD in a cross-sectional study nested within the large Mexican Teacher's Cohort. This study included 491 premenopausal women with a mean age of 42.9 years. Serum 25(OH)D3 levels were measured by liquid chromatography/tandem mass spectrometry. Linear regression and non-linear adjusted models were used to estimate the association of MD with serum 25(OH)D3. Median serum 25(OH)D3 level was 27.3 (23.3-32.8) (ng/ml). Forty one (8%) women had 25(OH)D3 levels in the deficient range (< 20 ng/ml). Body mass index (BMI) and total physical activity were significantly correlated with 25(OH)D3 (r = -0.109, P = 0.019 and r = 0.095, P = 0.003, respectively). In the multivariable linear regression, no significant association was observed between 25(OH)D3 levels and MD overall. However, in stratified analyses, higher serum 25(OH)D3 levels (≥27.3 ng/ml) were significantly inversely associated with percent MD among women with BMI below the median (β = -0.52, P = 0.047). Although no significant association was observed between serum 25(OH)D3 and percent MD in the overall population, specific subgroups of women may benefit from higher serum 25(OH)D3 levels.

The Western dietary pattern is associated with increased serum concentrations of free estradiol in postmenopausal women: implications for breast cancer prevention

Little is known about the possible influence of food consumption on the serum concentrations of endogenous sex hormones in postmenopausal women. We evaluated the relationships of the Western dietary pattern with serum concentrations of free estradiol and testosterone of postmenopausal women to test the hypothesis that a highly Western dietary pattern is associated with high serum concentrations of these hormones. We used data from a representative subsample of 305 women from the control group of a population-based case-control study conducted in Mexico from 2004 to 2007. A Western dietary pattern index value was compared with log natural serum concentrations of testosterone and estradiol using multiple linear regression models. The median values of serum concentrations of free estradiol and testosterone were 0.26 pg/mL (interquartile range, 0.14-0.43) and 0.40 pg/mL (interquartile range, 0.30-0.70), respectively. A multiple linear regression model showed that for each unit increase in the Western dietary pattern index, there was a 16.2% increase in the serum concentrations of free estradiol (β=0.15; 95% confidence interval [CI], 0.01-0.29); for each additional serving per week of chicken eggs, the increase was 31.0% (β=0.27; 95% CI, 0.106-0.441); for each additional serving per week of red meat, the increase was 64.9% (β=0.50; 95% CI, 0.01-1.01). There was no relationship found between dietary patterns and serum concentrations of free testosterone. The present findings suggest that intake of a Western diet, particularly of chicken eggs and meat, increases serum concentrations of free estradiol; these results have implications for breast cancer prevention.

Knowledge and recommendations regarding breast cancer early screening in an upper middle income country: Primary and secondary health care professionals

OBJECTIVE

To compare the current breast cancer prevention and control Mexican standard with recommendations that health care professionals provide to women for breast self-exams, clinical breast exams and mammography, as well as health care professional knowledge of the risk factors for and main clinical signs of the disease.

METHODS

In 2012, using a cross-sectional design, trained interviewers surveyed health care providers in a sample of 798 medical units, of which 756 corresponded to the first and second levels of medical care. One health care professional from each unit was interviewed for the study. The sampling method was systematic and representative of the national and regional levels. Relative frequencies and 95% confidence intervals (CI) were obtained using the weighting factor assigned to each medical unit.

RESULTS

Regarding the indicator about recommendations provided to the population regarding early screening for and risk factors and clinical signs of breast cancer, the average number of health care professional responses in accordance with the Mexican standard was 10.7 (95% CI 10.0-11.4) out of a maximum of 28 points, which corresponds to an average rate of 38.2% of responses (95% CI 35.6-40.8). The percentage of correct answers increased in all areas of breast exam knowledge as training hours in the previous year increased.

CONCLUSIONS

Health care professionals are unaware of the current standards on breast cancer; therefore, these recommendations are not routinely translated into health care practice, which is a barrier to increasing the coverage of screening programs in health care services.

Cigarette Smoking and Breast Cancer Risk in Hispanic and Non-Hispanic White Women: The Breast Cancer Health Disparities Study

OBJECTIVE

Few epidemiological studies have included Hispanics with the evaluation of the effects of cigarette smoking and breast cancer. We examined the relationship between cigarette smoking, ethnicity, and breast cancer risk using data from the Breast Cancer Health Disparities Study (BCHDS).

MATERIALS AND METHODS

The BCHDS is a consortium of three population-based case-control studies, including U.S. non-Hispanic whites (NHWs) (1,525 cases; 1,593 controls), U.S. Hispanics/Native Americans (1,265 cases; 1,495 controls), and Mexican women (990 cases; 1,049 controls). Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Breast cancer risk was elevated among Mexican former smokers (OR 1.43, 95% CI 1.04-1.96) and among those who smoked ≥ 31 years (OR 1.95, 95% CI 1.13-3.35), compared to never smokers. In addition, Mexican former smokers with a history of alcohol consumption had increased breast cancer risk (OR 2.30, 95% CI 1.01-5.21). Among NHW premenopausal women, breast cancer risk was increased for smoking ≥ 20 cigarettes per day (OR 1.61, 95% CI 1.07-2.41).

CONCLUSION

Our findings suggest the possibility of ethnic differences with the associations between cigarette smoking and breast cancer risk.

Adherence to the World Cancer Research Fund/American Institute for Cancer Research cancer prevention recommendations and breast cancer risk in the Cancer de Màma (CAMA) study

OBJECTIVE

We investigated the association between adherence to the recommendations of the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) and breast cancer (BC) risk in the Cancer de Màma (CAMA) study in a Mexican population.

DESIGN

Population-based case-control study.

SUBJECTS

Incident BC cases (n 1000) and controls (n 1074) matched on age, region and health-care system were recruited.

SETTING

In-person interviews were conducted to assess BC risk factors and habitual diet was assessed with an FFQ. Conformity to the WCRF/AICR recommendations was evaluated through a score incorporating seven WCRF/AICR components (body fatness, physical activity, foods and drinks that promote weight gain, plant foods, animal foods, alcoholic drinks and breast-feeding), with high scores indicating adherence to the WCRF/AICR recommendations.

RESULTS

No statistically significant associations between WCRF/AICR score and risk of BC were observed. After excluding BMI from the WCRF/AICR score, the top quartile was associated with a decreased BC risk overall, with ORQ4-Q1=0.68 (95% CI 0.49, 0.92, P trend=0.03), and among postmenopausal women, with ORQ4-Q1=0.60 (95% CI 0.39, 0.94, P trend=0.03). Inverse associations were observed between BMI and risk of BC overall and among premenopausal women, with OR=0.57 (95% CI 0.42, 0.76, P trend <0.01) and 0.48 (95% CI 0.31, 0.73, P trend<0.01), respectively. Physical activity level was inversely associated with BC risk.

CONCLUSIONS

The WCRF/AICR index was not related with BC risk in the CAMA study. A combination of six components excluding BMI showed strong protective associations, particularly in postmenopausal women. Further prospective studies are required to clarify the role of adherence to WCRF/AICR recommendations, particularly with respect to BMI, in the Mexican population.

A prospective study of occupational physical activity and breast cancer risk

PURPOSE

Physical activity has been associated with reduced breast cancer risk, but studies of occupational activity have produced inconsistent results. The purpose of this study was to evaluate the relationship between occupational physical activity and breast cancer in a prospective study of women with a family history of breast cancer.

METHODS

We studied breast cancer risk in 47,649 Sister Study participants with an occupational history. Information on occupational activity and breast cancer risk factors was collected during baseline interviews (2004-2009). Physical activity at each job was self-reported and categorized as mostly sitting, sitting and standing equally, mostly standing, and active. Multivariable Cox proportional hazards regression was used to evaluate associations between lifetime occupational activity and incident breast cancer, after adjusting for established risk factors and recreational activity.

RESULTS

During follow-up, a total of 1,798 breast cancer diagnoses were reported. Compared with women who did not spend any time in active jobs, women who spent a high proportion (≥75%) of their working years in active jobs had a reduced risk of breast cancer (HR 0.72; 95% CI 0.52-0.98). Associations were strongest among overweight (HR 0.64; 95% CI 0.42-0.98) and postmenopausal (HR 0.67; 95% CI 0.45-0.98) women.

CONCLUSIONS

Occupational activity was associated with a reduced risk of breast cancer. Occupational activity is a domain of physical activity that should be further examined in studies of postmenopausal breast cancer risk. Additional research is necessary to better understand the mechanisms underlying the relationships between occupational activity, body size, and breast cancer.

Interaction between common breast cancer susceptibility variants, genetic ancestry, and nongenetic risk factors in Hispanic women

BACKGROUND

Most genetic variants associated with breast cancer risk have been discovered in women of European ancestry, and only a few genome-wide association studies (GWAS) have been conducted in minority groups. This research disparity persists in post-GWAS gene-environment interaction analyses. We tested the interaction between hormonal and lifestyle risk factors for breast cancer, and ten GWAS-identified SNPs among 2,107 Hispanic women with breast cancer and 2,587 unaffected controls, to gain insight into a previously reported gene by ancestry interaction in this population.

METHODS

We estimated genetic ancestry with a set of 104 ancestry-informative markers selected to discriminate between Indigenous American and European ancestry. We used logistic regression models to evaluate main effects and interactions.

RESULTS

We found that the rs13387042-2q35(G/A) SNP was associated with breast cancer risk only among postmenopausal women who never used hormone therapy [per A allele OR: 0.94 (95% confidence intervals, 0.74-1.20), 1.20 (0.94-1.53), and 1.49 (1.28-1.75) for current, former, and never hormone therapy users, respectively, Pinteraction 0.002] and premenopausal women who breastfed >12 months [OR: 1.01 (0.72-1.42), 1.19 (0.98-1.45), and 1.69 (1.26-2.26) for never, <12 months, and >12 months breastfeeding, respectively, Pinteraction 0.014].

CONCLUSIONS

The correlation between genetic ancestry, hormone replacement therapy use, and breastfeeding behavior partially explained a previously reported interaction between a breast cancer risk variant and genetic ancestry in Hispanic women.

IMPACT

These results highlight the importance of understanding the interplay between genetic ancestry, genetics, and nongenetic risk factors and their contribution to breast cancer risk.

Active and passive cigarette smoking and mortality among Hispanic and non-Hispanic white women diagnosed with invasive breast cancer

PURPOSE

Women who smoke at breast cancer diagnosis have higher risk of breast cancer-specific and all-cause mortality than nonsmokers; however, differences by ethnicity or prognostic factors and risk for noncancer mortality have not been evaluated.

METHODS

We examined associations of active and passive smoke exposure with mortality among Hispanic (n = 1020) and non-Hispanic white (n = 1198) women with invasive breast cancer in the Breast Cancer Health Disparities Study (median follow-up of 10.6 years).

RESULTS

Risk of breast cancer-specific (HR = 1.55, 95% CI = 1.11-2.16) and all-cause (HR = 1.68, 95% CI = 1.30-2.17) mortality was increased for current smokers, with similar results stratified by ethnicity. Ever smokers had an increased risk of noncancer mortality (HR = 1.68, 95% CI = 1.12-2.51). Associations were strongest for current smokers who smoked for 20 years or more were postmenopausal, overweight and/or obese, or reported moderate and/or high alcohol consumption; however, interactions were not significant. Breast cancer-specific mortality was increased two fold for moderate and/or high recent passive smoke exposure among never smokers (HR = 2.12, 95% CI = 1.24-3.63).

CONCLUSIONS

Findings support associations of active-smoking and passive-smoking diagnosis with risk of breast cancer-specific and all-cause mortality and ever smoking with noncancer mortality, regardless of ethnicity, and other factors. Smoking is a modifiable lifestyle factor and effective smoking cessation, and maintenance programs should be routinely recommended for women with breast cancer.

Endogenous hormones, inflammation, and body size in premenopausal Mexican women: results from the Mexican Teachers' Cohort (MTC, ESMaestras)

PURPOSE

Obesity is a major risk factor for several cancers, including female cancers. Endogenous hormones and inflammatory factors may mediate the association between anthropometric measures and cancer risk, although these associations have been studied mainly in Caucasians. The aim of the current study was to explore the association of circulating hormones, adipokines, and inflammatory factors with obesity and overweight in premenopausal Mexican women.

METHODS

We conducted a cross-sectional analysis of 504 premenopausal women from the large Mexican Teachers' Cohort (MTC, ESMaestras) study to determine the association of insulin-like growth factor I (IGF-I), its major circulating binding protein (IGFBP-3), leptin, adiponectin, C-peptide, and C-reactive protein with comprehensive measures of body size. Biomarkers were measured by immunoassays. Multivariate regression analyses were performed to compare geometric mean biomarker concentrations with measured markers of body size and adiposity.

RESULTS

Mean IGF-I and IGFBP-3 concentrations significantly increased with increasing height and leg length. Concentrations of IGF-I, adiponectin, and the IGF-I/IGFBP-3 ratio strongly decreased with increasing BMI, weight, waist and hip circumferences, waist-to-hip ratio (WHpR), and waist-to-height ratio (WHtR), while CRP, leptin, C-peptide concentrations, and the leptin/adiponectin ratio strongly increased. Adiponectin and the leptin/adiponectin ratio remained significantly related to measures of central adiposity (waist circumference, WHpR, and WHtR) after adjustment by body mass index.

CONCLUSIONS

The results of our study suggest a strong relation between biomarkers and body size in this study population and suggest that different fat depots may have different metabolic properties.

Recurrent BRCA1 and BRCA2 mutations in Mexican women with breast cancer

BACKGROUND

Germline mutations in the BRCA1 and BRCA2 genes confer an estimated 58% to 80% lifetime risk of breast cancer. In general, screening is done for cancer patients if a relative has been diagnosed with breast or ovarian cancer. There are few data on the prevalence of mutations in these genes in Mexican women with breast cancer and this hampers efforts to develop screening policies in Mexico.

METHODS

We screened 810 unselected women with breast cancer from three cities in Mexico (Mexico City, Veracruz, and Monterrey) for mutations in BRCA1 and BRCA2, including a panel of 26 previously reported mutations.

RESULTS

Thirty-five mutations were identified in 34 women (4.3% of total) including 20 BRCA1 mutations and 15 BRCA2 mutations. Twenty-two of the 35 mutations were recurrent mutations (62.8%). Only five of the 34 mutation carriers had a first-degree relative with breast cancer (three with BRCA1 and two with BRCA2 mutations).

CONCLUSION

These results support the rationale for a strategy of screening for recurrent mutations in all women with breast cancer in Mexico, as opposed to restricting screening to those with a sister or mother with breast or ovarian cancer.

IMPACT

These results will impact cancer genetic testing in Mexico and the identification of at-risk individuals who will benefit from increased surveillance. Cancer Epidemiol Biomarkers Prev; 24(3); 498-505. ©2014 AACR.

Diet and lifestyle factors modify immune/inflammation response genes to alter breast cancer risk and prognosis: the Breast Cancer Health Disparities Study

Tumor necrosis factor-α (TNF) and toll-like receptors (TLR) are important mediators of inflammation. We examined 10 of these genes with respect to breast cancer risk and mortality in a genetically admixed population of Hispanic/Native American (NA) (2111 cases, 2597 controls) and non-Hispanic white (NHW) (1481 cases, 1585 controls) women. Additionally, we explored if diet and lifestyle factors modified associations with these genes. Overall, these genes (collectively) were associated with breast cancer risk among women with >70% NA ancestry (P(ARTP) = 0.0008), with TLR1 rs7696175 being the primary risk contributor (OR 1.77, 95% CI 1.25, 2.51). Overall, TLR1 rs7696175 (HR 1.40, 95% CI 1.03, 1.91; P(adj) = 0.032), TLR4 rs5030728 (HR 1.96, 95% CI 1.30, 2.95; P(adj) = 0.014), and TNFRSF1A rs4149578 (HR 2.71, 95% CI 1.28, 5.76; P(adj) = 0.029) were associated with increased breast cancer mortality. We observed several statistically significant interactions after adjustment for multiple comparisons, including interactions between our dietary oxidative balance score and CD40LG and TNFSF1A; between cigarette smoking and TLR1, TLR4, and TNF; between body mass index (BMI) among pre-menopausal women and TRAF2; and between regular use of aspirin/non-steroidal anti-inflammatory drugs and TLR3 and TRA2. In conclusion, our findings support a contributing role of certain TNF-α and TLR genes in both breast cancer risk and survival, particularly among women with higher NA ancestry. Diet and lifestyle factors appear to be important mediators of the breast cancer risk associated with these genes.

Associations between ALOX, COX, and CRP polymorphisms and breast cancer among Hispanic and non-Hispanic white women: The breast cancer health disparities study

Chronic inflammation is suggested to be associated with specific cancer sites, including breast cancer. Recent research has focused on the roles of genes involved in the leukotriene/lipoxygenase and prostaglandin/cyclooxygenase pathways in breast cancer etiology. We hypothesized that genes in ALOX/COX pathways and CRP polymorphisms would be associated with breast cancer risk and mortality in our sample of Hispanic/Native American (NA) (1430 cases, 1599 controls) and non-Hispanic white (NHW) (2093 cases, 2610 controls) women. A total of 104 Ancestral Informative Markers was used to distinguish European and NA ancestry. The adaptive rank truncated product (ARTP) method was used to determine the significance of associations for each gene and the inflammation pathway with breast cancer risk and by NA ancestry. Overall, the pathway was associated with breast cancer risk (PARTP = 0.01). Two-way interactions with NA ancestry (P(adj)  < 0.05) were observed for ALOX12 (rs2292350, rs2271316) and PTGS1 (rs10306194). We observed increases in breast cancer risk in stratified analyses by tertiles of polyunsaturated fat intake for ALOX12 polymorphisms; the largest increase in risk was among women in the highest tertile with ALOX12 rs9904779CC (Odds Ratio (OR), 1.49; 95% Confidence Interval (CI) 1.14-1.94, P(adj) = 0.01). In a sub-analysis stratified by NSAIDs use, two-way interactions with NSAIDs use were found for ALOX12 rs9904779 (P(adj)  = 0.02), rs434473 (P(adj ) = 0.02), and rs1126667 (P(adj)  =  0.01); ORs for ALOX12 polymorphisms ranged from 1.55 to 1.64 among regular users. Associations were not observed with breast cancer mortality. These findings could support advances in the discovery of new pathways related to inflammation for breast cancer treatment.

Genome-wide association study of breast cancer in Latinas identifies novel protective variants on 6q25

The genetic contributions to breast cancer development among Latinas are not well understood. Here we carry out a genome-wide association study of breast cancer in Latinas and identify a genome-wide significant risk variant, located 5′ of the Estrogen Receptor 1 gene (ESR1; 6q25 region). The minor allele for this variant is strongly protective (rs140068132: odds ratio (OR) 0.60, 95% confidence interval (CI) 0.53–0.67, P=9 × 10⁻¹⁸), originates from Indigenous Americans and is uncorrelated with previously reported risk variants at 6q25. The association is stronger for oestrogen receptor-negative disease (OR 0.34, 95% CI 0.21–0.54) than oestrogen receptor-positive disease (OR 0.63, 95% CI 0.49–0.80; P heterogeneity=0.01) and is also associated with mammographic breast density, a strong risk factor for breast cancer (P=0.001). rs140068132 is located within several transcription factor-binding sites and electrophoretic mobility shift assays with MCF-7 nuclear protein demonstrate differential binding of the G/A alleles at this locus. These results highlight the importance of conducting research in diverse populations.

Genome-wide association studies (GWAS) have revealed gene variants associated with breast cancer, but their association with breast cancer development in Latinas is not clear. Here, the authors carry out a GWAS of breast cancer in Latinas and identify a significant protective variant of Indigenous American origin in the 6q25 region.

Associations between CYP19A1 polymorphisms, Native American ancestry, and breast cancer risk and mortality: the Breast Cancer Health Disparities Study

The cytochrome p450 family 19 gene (CYP19A1) encodes for aromatase, which catalyzes the final step in estrogen biosynthesis and conversion of androgens to estrogens. Genetic variation in CYP19A1 is linked to higher circulating estrogen levels and increased aromatase expression. Using data from the Breast Cancer Health Disparities Study, a consortium of three population-based case-control studies in the United States (n = 3,030 non-Hispanic Whites; n = 2,893 Hispanic/Native Americans (H/NA) and Mexico (n = 1,810), we examined influence of 25 CYP19A1 tagging single-nucleotide polymorphisms (SNPs) on breast cancer risk and mortality, considering NA ancestry. Odds ratios (ORs) and 95 % confidence intervals (CIs) and hazard ratios estimated breast cancer risk and mortality. After multiple comparison adjustment, none of the SNPs were significantly associated with breast cancer risk or mortality. Two SNPs remained significantly associated with increased breast cancer risk in women of moderate to high NA ancestry (≥29 %): rs700518, ORGG 1.36, 95 % CI 1.11-1.67 and rs11856927, ORGG 1.35, 95 % CI 1.05-1.72. A significant interaction was observed for rs2470144 and menopausal status (p adj = 0.03); risk was increased in postmenopausal (ORAA 1.22, 95 % CI 1.05-1.14), but not premenopausal (ORAA 0.78, 95 % CI 0.64-0.95) women. The absence of an overall association with CYP19A1 and breast cancer risk is similar to previous literature. However, this analysis provides support that variation in CYP19A1 may influence breast cancer risk differently in women with moderate to high NA ancestry. Additional research is warranted to investigate the how variation in an estrogen-regulating gene contributes to racial/ethnic disparities in breast cancer.

Genetic variation in the JAK/STAT/SOCS signaling pathway influences breast cancer-specific mortality through interaction with cigarette smoking and use of aspirin/NSAIDs: the Breast Cancer Health Disparities Study

The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway is involved in immune function and cell growth; genetic variation in this pathway could influence breast cancer risk. We examined 12 genes in the JAK/STAT/SOCS signaling pathway with breast cancer risk and mortality in an admixed population of Hispanic (2,111 cases, 2,597 controls) and non-Hispanic white (1,481 cases, 1,585 controls) women. Associations were assessed by Indigenous American (IA) ancestry. After adjustment for multiple comparisons, JAK1 (three of ten SNPs) and JAK2 (4 of 11 SNPs) interacted with body mass index (BMI) among pre-menopausal women, while STAT3 (four of five SNPs) interacted significantly with BMI among post-menopausal women to alter breast cancer risk. STAT6 rs3024979 and TYK2 rs280519 altered breast cancer-specific mortality among all women. Associations with breast cancer-specific mortality differed by IA ancestry; SOCS1 rs193779, STAT3 rs1026916, and STAT4 rs11685878 associations were limited to women with low IA ancestry, and associations with JAK1 rs2780890, rs2254002, and rs310245 and STAT1 rs11887698 were observed among women with high IA ancestry. JAK2 (5 of 11 SNPs), SOCS2 (one of three SNPs), and STAT4 (2 of 20 SNPs) interacted with cigarette smoking status to alter breast cancer-specific mortality. SOCS2 (one of three SNPs) and all STAT3, STAT5A, and STAT5B SNPs significantly interacted with use of aspirin/NSAIDs to alter breast cancer-specific mortality. Genetic variation in the JAK/STAT/SOCS pathway was associated with breast cancer-specific mortality. The proportion of SNPs within a gene that significantly interacted with lifestyle factors lends support for the observed associations.

Prediabetes, diabetes, and risk of breast cancer: a case-control study

BACKGROUND AND AIMS

Although underlying mechanisms have been described to account for the association between prediabetes and diabetes with breast cancer, reported results have been inconsistent. We undertook this study to determine whether prediabetes and diabetes are risk factors for breast cancer in Mexican women with no family history of breast cancer in the mother, daughters, or sisters.

METHODS

A case-control study was carried out during 2011-2013. "Case" referred to patients with a histopathological diagnosis of breast cancer (incident and primary cases) (n = 240); "controls" were those with a BI-RADS 1 or 2 mammography result (n = 406). Categorization of prediabetes and diabetes was based on self-reporting or fasting glucose and glycated hemoglobin blood sampling results. Reproductive and sociodemographic data were collected by interview. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated using multivariate unconditional binary logistic regression analysis.

RESULTS

Prediabetes increased the risk of breast cancer in postmenopausal women (adjusted OR 2.08, 95% CI 1.10-3.96) as did diabetes (adjusted OR 2.85, 95% CI 1.55-5.26). A history of diabetes preceding breast cancer by ≥7 years and <7 years were both associated with an increased risk for breast cancer (adjusted OR 2.80, 95% CI 1.40-5.60 and 3.00, 95% CI 1.50-5.90, respectively).

CONCLUSIONS

This is the first study in Mexico evaluating prediabetes and diabetes as breast cancer risk factors in women with no first-degree relatives with breast cancer. Our findings suggest that women with prediabetes and diabetes should be considered a more vulnerable population for early breast cancer detection.

Genetic variants in interleukin genes are associated with breast cancer risk and survival in a genetically admixed population: the Breast Cancer Health Disparities Study

Interleukins (ILs) are key regulators of immune response. Genetic variation in IL genes may influence breast cancer risk and mortality given their role in cell growth, angiogenesis and regulation of inflammatory process. We examined 16 IL genes with breast cancer risk and mortality in an admixed population of Hispanic/Native American (NA) (2111 cases and 2597 controls) and non-Hispanic white (NHW) (1481 cases and 1585 controls) women. Adaptive Rank Truncated Product (ARTP) analysis was conducted to determine gene significance and lasso (least absolute shrinkage and selection operator) was used to identify potential gene by gene and gene by lifestyle interactions. The pathway was statistically significant for breast cancer risk overall (P ARTP = 0.0006), for women with low NA ancestry (P(ARTP) = 0.01), for premenopausal women (P(ARTP) = 0.02), for estrogen receptor (ER)+/progesterone receptor (PR)+ tumors (P(ARTP) = 0.03) and ER-/PR- tumors (P(ARTP) = 0.02). Eight of the 16 genes evaluated were associated with breast cancer risk (IL1A, IL1B, IL1RN, IL2, IL2RA, IL4, IL6 and IL10); four genes were associated with breast cancer risk among women with low NA ancestry (IL1B, IL6, IL6R and IL10), two were associated with breast cancer risk among women with high NA ancestry (IL2 and IL2RA) and four genes were associated with premenopausal breast cancer risk (IL1A, IL1B, IL2 and IL3). IL4, IL6R, IL8 and IL17A were associated with breast cancer-specific mortality. We confirmed associations with several functional polymorphisms previously associated with breast cancer risk and provide support that their combined effect influences the carcinogenic process.

Anthropometry, silhouette trajectory, and risk of breast cancer in Mexican women

BACKGROUND

Obesity has been associated with breast cancer risk in the Caucasian population but the association remains unclear in the Hispanics. Previous studies conducted among Hispanics in the U.S. have shown inconsistent results.

PURPOSE

The association between anthropometry, body shape evolution across lifetime, and the risk of breast cancer was assessed using a multi-center population-based case-control study conducted in Mexico.

METHODS

One thousand incident cases and 1074 matched control women aged 35-69 years were recruited between 2004 and 2007, and analyzed in 2011-2012. Conditional logistic regression models were used.

RESULTS

Height was related to an increased risk of breast cancer in both premenopausal (p trend=0.03) and postmenopausal women (p trend=0.002). In premenopausal women, increase in BMI; waist circumference (WC); hip circumference (HC); and waist-hip ratio (WHR) were inversely associated with breast cancer risk (p trends<0.001 for BMI and WC, 0.003 for HC, and 0.016 for WHR). In postmenopausal women, decreased risks were observed for increased WC (p trend=0.004) and HC (p trend=0.009) among women with time since menopause <10 years. Further analysis of body shape evolution throughout life showed strong and significant increase in risk of breast cancer among women with increasing silhouettes size over time compared to women with no or limited increase.

CONCLUSIONS

These findings suggest that anthropometric factors may have different associations with breast cancer risk in Hispanic women than in Caucasian women. This study also shows the importance of considering the evolution of body shape throughout life.

Circulating concentrations of insulin-like growth factor-I, insulin-like growth factor-binding protein-3, genetic polymorphisms and mammographic density in premenopausal Mexican women: results from the ESMaestras cohort

The insulin-like growth factor (IGF) axis plays an essential role in the development of the mammary gland. High circulating levels of IGF-I and of its major binding protein IGFBP3 have been related with increased mammographic density in Caucasian premenopausal women. Some common single nucleotide polymorphisms (SNPs) in genes of the IGF pathway have also been suggested to play a role in mammographic density. We conducted a cross-sectional study nested within the large Mexican ESMaestras cohort to investigate the relation between circulating levels of IGF-I, IGFBP-3, the IGF-I/IGFBP-3 ratio, five common SNPs in the IGF-1, IGFBP-3 and IGF-1R genes and mammographic density in 593 premenopausal Mexican women. Mean age at mammogram was 43.1 (standard deviation, SD = 3.7) years, and average body mass index (BMI) at recruitment was 28.5 kg/m(2). Mean percent mammographic density was 36.5% (SD: 17.1), with mean dense tissue area of 48.3 (SD: 33.3) cm(2) . Mean IGF-I and IGFBP-3 concentrations were 15.33 (SD: 5.52) nmol/l and 114.96 (SD: 21.34) nmol/l, respectively. No significant associations were seen between percent density and biomarker concentrations, but women with higher IGF-I and IGF-I/IGFBP-3 concentrations had lower absolute dense (p(trend) = 0.03 and 0.09, respectively) and nondense tissue areas (p(trend) < 0.001 for both parameters). However, these associations were null after adjustment by BMI. SNPs in specific genes were associated with circulating levels of growth factors, but not with mammographic density features. These results do not support the hypothesis of a strong association between circulating levels of growth hormones and mammographic density in Mexican premenopausal women.

Association between rs2981582 polymorphism in the FGFR2 gene and the risk of breast cancer in Mexican women

BACKGROUND AND AIMS

The rs2981582 single nucleotide polymorphism in the fibroblast growth factor receptor 2 gene has been consistently associated with an increased risk of breast cancer. We evaluated the effect of rs2981582 polymorphism in the FGFR2 gene on the risk of breast cancer and its interaction with non-genetic risk factors.

METHODS

A population-based case-control study was conducted in Mexico. Data from 687 cases and 907 controls were analyzed.

RESULTS

The T allele of the rs2981582 polymorphism was associated with an increased risk of breast cancer (ORper allele = 1.24, 95% CI 1.06-1.46). There was also an interaction between this polymorphism and alcohol consumption (p = 0.043). The effect of alcohol consumption on the risk of breast cancer varied according to the allelic variants of the rs2981582 polymorphism in the FGFR2 gene: OR = 3.97 (95% CI 2.10-7.49), OR = 2.01 (95% CI 1.23-3.29) and OR = 1.21 (95% CI 0.48-3.05) for genotypes CC, CT and TT, respectively.

CONCLUSIONS

This is the first study exploring the association between rs2981582 polymorphism in the FGFR2 gene and breast cancer risk in Mexican women. The interaction found may be of great public health interest because alcohol consumption is a modifiable breast cancer risk factor. Therefore, replication of this finding is of foremost importance.

Genetic ancestry modifies the association between genetic risk variants and breast cancer risk among Hispanic and non-Hispanic white women

Hispanic women in the USA have lower breast cancer incidence than non-Hispanic white (NHW) women. Genetic factors may contribute to this difference. Breast cancer genome-wide association studies (GWAS) conducted in women of European or Asian descent have identified multiple risk variants. We tested the association between 10 previously reported single nucleotide polymorphisms (SNPs) and risk of breast cancer in a sample of 4697 Hispanic and 3077 NHW women recruited as part of three population-based case-control studies of breast cancer. We used stratified logistic regression analyses to compare the associations with different genetic variants in NHWs and Hispanics classified by their proportion of Indigenous American (IA) ancestry. Five of 10 SNPs were statistically significantly associated with breast cancer risk. Three of the five significant variants (rs17157903-RELN, rs7696175-TLR1 and rs13387042-2q35) were associated with risk among Hispanics but not in NHWs. The odds ratio (OR) for the heterozygous at 2q35 was 0.75 [95% confidence interval (CI) = 0.50-1.15] for low IA ancestry and 1.38 (95% CI = 1.04-1.82) for high IA ancestry (P interaction 0.02). The ORs for association at RELN were 0.87 (95% CI = 0.59-1.29) and 1.69 (95% CI = 1.04-2.73), respectively (P interaction 0.03). At the TLR1 locus, the ORs for women homozygous for the rare allele were 0.74 (95% CI = 0.42-1.31) and 1.73 (95% CI = 1.19-2.52) (P interaction 0.03). Our results suggest that the proportion of IA ancestry modifies the magnitude and direction of the association of 3 of the 10 previously reported variants. Genetic ancestry should be considered when assessing risk in women of mixed descent and in studies designed to discover causal mutations.

Genetic variation in bone morphogenetic proteins and breast cancer risk in hispanic and non-hispanic white women: The breast cancer health disparities study

Bone morphogenetic proteins (BMP) are thought to be important in breast cancer promotion and progression. We evaluated genetic variation in BMP-related genes and breast cancer risk among Hispanic (2,111 cases, 2,597 controls) and non-Hispanic White (NHW) (1,481 cases, 1,586 controls) women who participated in the 4-Corner's Breast Cancer Study, the Mexico Breast Cancer Study and the San Francisco Bay Area Breast Cancer Study. BMP genes and their receptors evaluated include ACVR1, AVCR2A, ACVR2B, ACVRL1, BMP1, BMP2, BMP4, BMP6, BMP7, BMPR1A, BMPR1B, BMPR2, MSTN and GDF10. Additionally, 104 ancestral informative markers were assessed to discriminate between European and native American ancestry. The importance of estrogen on BMP-related associations was suggested through unique associations by menopausal status and estrogen (ER) and progesterone (PR) receptor status of tumors. After adjustment for multiple comparisons ACVR1 (8 SNPs) was modestly associated with ER+PR+ tumors [odds ratios (ORs) between 1.18 and 1.39 padj < 0.05]. ACVR1 (3 SNPs) and BMP4 (3 SNPs) were associated with ER+PR- tumors (ORs 0.59-2.07; padj < 0.05). BMPR2 was associated with ER-PR+ tumors (OR 4.20; 95% CI 1.62, 10.91; padj < 0.05) as was GDF10 (2 SNPs; ORs 3.62 and 3.85; padj < 0.05). After adjustment for multiple comparisons several SNPs remained associated with ER-PR- tumors (padj < 0.05) including ACVR1 BMP4 and GDF10 (ORs between 0.53 and 2.12). Differences in association also were observed by percentage of native ancestry and menopausal status. Results support the hypothesis that genetic variation in BMPs is associated with breast cancer in this admixed population.

Moderate-intensity physical activity ameliorates the breast cancer risk in diabetic women

OBJECTIVE

To evaluate the association between self-reported diabetes and the risk of breast cancer (BC) and its interaction with moderate-intensity physical activity in pre- and postmenopausal Mexican women.

RESEARCH DESIGN AND METHODS

A population-based case-control study was conducted using 1,000 incident case subjects and 1,074 control subjects. Blood samples and information on health, diet, physical activity, and anthropometric measurements were obtained.

RESULTS

The association between diabetes and BC risk decreased with increasing tertiles of moderate-intensity physical activity (odds ratio [OR] = 4.9 [95% CI 2.3-10.8]; 3.0 [1.3-6.9]; and 1.0 [0.1-9.2], respectively, for each tertile) (test for interaction = 0.04). Compared with the women in the lowest tertiles, increased risk was observed in those premenopausal women with the highest serum C-peptide, IGF-1, and IGF-1 binding protein 3 levels.

CONCLUSIONS

Moderate-intensity physical activity can substantially ameliorate the increased BC risk in diabetic women.

Associations between TCF7L2 polymorphisms and risk of breast cancer among Hispanic and non-Hispanic white women: the Breast Cancer Health Disparities Study

The transcription factor 7-like 2 (TCF7L2) gene is part of the Wnt/β-catenin signaling pathway and plays a critical role in cell development and growth regulation. TCF7L2 variants rs12255372 and rs7903146 have been associated with risk of Type 2 diabetes. Few epidemiological studies have examined the association between TCF7L2 and breast cancer risk. We investigated the associations between 25 TCF7L2 single nucleotide polymorphisms (SNPs) and breast cancer in Hispanic and non-Hispanic white (NHW) women from the 4-Corner's Breast Cancer Study, the San Francisco Bay Area Breast Cancer Study, and the Mexico Breast Cancer Study. A total of 4,703 Hispanic (2,093 cases, 2,610 controls) and 3,031 NHW (1,431 cases, 1,600 controls) women were included. Odds ratios (OR) and 95 % confidence intervals (CI) were calculated using logistic regression to estimate the association between the TCF7L2 SNPs and breast cancer risk. We also examined effect modification by self-reported ethnicity, genetic admixture, and diabetes history. After adjusting for multiple comparisons, four TCF7L2 SNPs were significantly associated with breast cancer overall: rs7903146 (OR(TT) 1.24; 95 % CI 1.03-1.49), rs3750805 (OR(AT/TT) 1.15; 95 % CI 1.03-1.28), rs7900150 (OR(AA) 1.23; 95 % 1.07-1.42), and rs1225404 (OR(CC) 0.82; 95 % 0.70-0.94). Among women with a history of diabetes, the TT genotype of rs3750804 increased breast cancer risk (OR, 2.46; 95 % CI 1.28-4.73). However, there was no association among women without a diabetes history (OR, 1.06; 95 % CI 0.85-1.32). We did not find significant interactions by ethnicity or by genetic admixture. Findings support an association between TCF7L2 and breast cancer and history of diabetes modifies this association for specific variants.

Serum 25-hydroxyvitamin D and risk of breast cancer: results of a large population-based case-control study in Mexican women

PURPOSE

Epidemiologic studies have suggested that higher levels of circulating vitamin D may reduce breast cancer risk, but no studies have investigated this association among women in developing countries, and very few studies have further investigated this association according to menopausal status.

METHODS

A population-based case-control study in Mexico with 1,000 incident breast cancer cases aged 35-69 years, enrolled shortly after diagnosis (0-6 days) and frequency-matched to 1,074 controls on age, region, and health care system, was used to assess the association between serum 25-hydroxyvitamin D [25(OH)D] levels with overall, pre- and postmenopausal breast cancer risk. 25(OH)D concentration was measured on a random sub-sample of women (573 cases and 639 matched controls) using a liquid chromatography/tandem mass spectrometry method. Odds ratios (ORs) and 95 % confidence intervals (CIs) were estimated from multivariable conditional logistic regression models.

RESULTS

Serum 25(OH)D concentration (per 10 ng/mL increase) showed a strong inverse association with risk of breast cancer among all (p(trend) = 0.001), pre- (p(trend) = 0.006) and postmenopausal women (p(trend) = 0.0001). Compared with a predefined lower concentration of 25(OH)D (<20 ng/mL), higher levels (>30 ng/mL) were associated with lower overall (OR = 0.53, 95 % CI: 0.28-1.00; p(trend) = 0.002), pre- (OR = 0.60, 95 % CI: 0.16-2.17; p(trend) = 0.07) and postmenopausal (OR = 0.37, 95 % CI: 0.16-0.82; p(trend) = 0.004) breast cancer risk.

CONCLUSIONS

The results of this large population-based case-control study indicate an inverse association between circulating vitamin D levels and breast cancer risk among pre- and postmenopausal Mexican women.