Adolescence and breast carcinoma risk

Association of obesity and menarche SNPs and interaction with environmental factors on precocious puberty

BACKGROUND

Obesity is an important cause for the precocious or early puberty. However, the association between obesity-related loci and the risk of precocious puberty as well as the effect of gene-environment interaction are unclear, especially in the Chinese children population.

METHODS

This was a case-control study using baseline data from two cohorts and hospital cases in China. 15 SNPs loci and several environmental factors were included in the analysis of 1201 participants. Chi-square test and logistic regression were used to analyze the association between SNPs and precocious puberty. Additionally, exploratory factor analysis was conducted on 13 environmental variables, and then to explore their interaction with genes on precocious puberty.

RESULTS

The effect allele C of rs571312, and G of rs12970134 MC4R were associated with precocious puberty in girls with obesity. Regarding the gene-environment interaction, we found that when girls were in the high socioeconomic status, the rs571312 (OR: 3.996; 95% CI: 1.694-9.423) and rs12970134 (OR: 3.529; 95% CI: 1.452-8.573) risk genotypes had a greater effect on precocious puberty.

CONCLUSIONS

The obesity risk gene polymorphisms MC4R rs571312 and rs12970134 were associated with precocious puberty in Chinese girls with obesity, and girls with risk genotypes and high socioeconomic status should be given extra attention.

IMPACT

This is the first study that identified the association between rs571312 and rs12970134 of MC4R gene and precocious puberty in Chinese children. We found that when girls were in the high socioeconomic status, the risk genotypes of rs571312 and rs12970134 had a greater effect on precocious puberty. The results of this study have great public health implications. It is recommended that girls who are in high socioeconomic status and have a high genetic risk for early sexual maturity should closely monitor their pubertal development and consider early intervention strategies.

Epidemiology and Risk Factors for Breast Cancer: 21st Century Advances, Gaps to Address through Interdisciplinary Science

Research methods to study risk factors and prevention of breast cancer have evolved rapidly. We focus on advances from epidemiologic studies reported over the past two decades addressing scientific discoveries, as well as their clinical and public health translation for breast cancer risk reduction. In addition to reviewing methodology advances such as widespread assessment of mammographic density and Mendelian randomization, we summarize the recent evidence with a focus on the timing of exposure and windows of susceptibility. We summarize the implications of the new evidence for application in risk stratification models and clinical translation to focus prevention-maximizing benefits and minimizing harm. We conclude our review identifying research gaps. These include: pathways for the inverse association of vegetable intake and estrogen receptor (ER)-ve tumors, prepubertal and adolescent diet and risk, early life adiposity reducing lifelong risk, and gaps from changes in habits (e.g., vaping, binge drinking), and environmental exposures.

Maternal thyroid disease in pregnancy and timing of pubertal development in sons and daughters

OBJECTIVE

To study whether maternal thyroid disease in pregnancy is associated with pubertal timing in sons and daughters.

DESIGN

Cohort study.

SETTING

National birth cohort and health registers.

PATIENT(S)

A total of 15,763 mothers and children from the Danish National Birth Cohort and its Puberty Cohort.

INTERVENTION(S)

Register-based and self-reported information on maternal thyroid diseases during pregnancy (hyperthyroidism, hypothyroidism, benign goiter, or no thyroid disease [reference group]).

MAIN OUTCOME MEASURE(S)

The adjusted mean age difference (months) at attaining several self-reported pubertal milestones collected every 6 months using an interval-censored regression and the average difference in age at attaining all pubertal milestones using the Huber-White robust variance estimation (primary outcome).

RESULT(S)

Sons of mothers with hyperthyroidism had earlier pubertal development (average difference, -2.9 [95% confidence interval (CI), -5.0 to -0.7] months) than unexposed sons. Maternal hypothyroidism was not associated with pubertal development in sons (average difference, -1.2 [95% CI, -5.1 to 2.7] months). We observed nonstatistically significant indications of earlier pubertal development in sons of mothers with benign goiter (average difference, -1.9 [95% CI, -4.6 to 0.9] months). Maternal thyroid disease was not associated with pubertal development in daughters (average difference (months), hyperthyroidism, -0.8 [95% CI, -2.8 to 1.2]; hypothyroidism, 0.3 [95% CI, -3.1 to 3.8]; and benign goiter, 0.7 [95% CI, -2.0 to 3.4]).

CONCLUSION(S)

We found indications of earlier pubertal development in sons of mothers with hyperthyroidism. More research is needed to further investigate the observed sex-specific association.

Cabbage and Sauerkraut Consumption in Adolescence and Adulthood and Breast Cancer Risk among US-Resident Polish Migrant Women

Background: Breast cancer (BC) incidence and mortality are lower in Poland than in the United States (US). However, Polish-born migrant women to US approach the higher BC mortality rates of US women. We evaluated the association between consumption of cabbage/sauerkraut foods and BC risk in Polish-born migrants to US. Methods: We conducted a case–control study of BC among Polish-born migrants in Cook County and the Detroit Metropolitan Area. Cases (n = 131) were 20–79 years old with histological/cytological confirmation of invasive BC. Population-based controls (n = 284) were frequency matched to cases on age and residence. Food frequency questionnaires assessed diet during adulthood and age 12–13 years. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated with conditional logistic regression. Consumption of total, raw/short-cooked, and long-cooked cabbage/sauerkraut foods was categorized as low, medium, or high (frequency of servings/week). Results: Higher consumption of total and raw/short-cooked cabbage/sauerkraut foods, during both adolescence and adulthood, was associated with a significantly lower BC risk. Consumption of long-cooked cabbage/sauerkraut foods was low and not significantly associated with risk. The multivariate OR for total cabbage/sauerkraut consumption, high vs. low (>4 vs. ≤2 servings/week) during adolescence was 0.36 (95% CI = 0.18–0.71, p_trend < 0.01) and 0.50 (95% CI = 0.23–1.06, p_trend = 0.08) during adulthood. For raw/short-cooked cabbage/sauerkraut (>3 vs. ≤1.5 servings/week), the ORs were 0.35 (95% CI = 0.16–0.72, p_trend < 0.01) during adolescence and 0.37 (95% CI = 0.17–0.78, p_trend < 0.01) during adulthood. For joint adolescent/adult consumption of raw/short-cooked cabbage/sauerkraut foods, (high, high) vs. (low, low), the OR was 0.23 (95% CI = 0.07–0.65). The significant association for high adolescent consumption of raw/short-cooked cabbage/sauerkraut foods and reduced BC risk was consistent across all levels of consumption in adulthood. Conclusion: Greater consumption of total and raw/short-cooked cabbage/sauerkraut foods either during adolescence or adulthood was associated with significantly reduced BC risk among Polish migrant women. These findings contribute to the growing literature suggesting a protective effect of a potentially modifiable factor, cruciferous vegetable intake, on breast cancer risk.

Cohort studies of long-term exposure to outdoor particulate matter and risks of cancer: A systematic review and meta-analysis

Robust evidence is needed for the hazardous effects of outdoor particulate matter (PM) on mortality and morbidity from all types of cancers. To summarize and meta-analyze the association between PM and cancer, published articles reporting associations between outdoor PM exposure and any type of cancer with individual outcome assessment that provided a risk estimate in cohort studies were identified via systematic searches. Of 3,256 records, 47 studies covering 13 cancer sites (30 for lung cancer, 12 for breast cancer, 11 for other cancers) were included in the quantitative evaluation. The pooled relative risks (RRs) for lung cancer incidence or mortality associated with every 10-μg/m³ PM_2.5 or PM₁₀ were 1.16 (95% confidence interval [CI], 1.10–1.23; I² = 81%) or 1.22 (95% CI, 1.02–1.45; I² = 96%), respectively. Increased but non-significant risks were found for breast cancer. Other cancers were shown to be associated with PM exposure in some studies but not consistently and thus warrant further investigation.

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Updated evidence for the association between PM and lung cancer risk has been provided

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Associations between PM and cancer risks from 13 sites were summarized

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Further studies should be conducted to fill the research gaps

The influence of parental age on timing of puberty: A study in the Danish National Birth Cohort

Aims: Concerns have been raised about the potential negative biological effect of postponed parenthood upon the health of subsequent generations, including reproductive health. This study aimed to estimate if high parental age at birth was associated with accelerated pubertal timing in offspring. Methods: In this large-scale cohort study, 15,819 children born by mothers in the Danish National Birth Cohort from 2000 to 2003 participated in a nationwide puberty cohort (participation rate 71%). Between 2012 and 2018, the children reported half-yearly information on pubertal status using web-based questionnaires from 11 years throughout puberty or 18 years of age. Information on parental age was drawn from nationwide registers. We estimated adjusted mean differences in months for age at attaining the pubertal milestones and pubertal timing overall between the pre-specified parental age groups: 20-29 (reference), 30-34 and advanced parental age groups (35-44 years for mothers and >35 years for fathers). Results: Overall, parental age at birth of the child was not associated with pubertal timing in daughters or sons. For sons of older fathers (>35 years), we observed indications towards slightly earlier pubertal timing in the range of 0.3-2.4 months for nearly all pubertal milestones, but all confidence intervals were wide, and many included the null. Conclusions: We found no strong association between parental age and timing of puberty, and we find it unlikely that the decreasing age in pubertal timing is a result of parental decision to delay childbearing.

In-Vitro Fertilization Impact on the Risk of Breast Cancer: A Review Article

Background

Due to the increasing prevalence of infertility, the number of referrals to infertility treatment centers has also increased. Nowadays, assisted reproductive technology (ART), including in vitro fertilization (IVF), is a treatment for infertility or genetic problems. Considering the possible consequences of this method among women undergoing in vitro fertilization (IVF) and kids conceived by IVF, extensive research has been conducted in this regard.

Methods

Overall, 100 articles were entered into the study, and relevant articles were searched and extracted from PubMed, Springer, and Google Scholar databases. In IVF procedure, medications such as Clomiphene citrate and gonadotropins are used to stimulate and mature follicles and thus increase ovulation.

Results

There are conflicting opinions on this issue. Some findings report a slight increase in cancer risk for hormone-sensitive cancers including breast cancer. The long-term use of IVF medications can increase estrogen hormones and cause excessive expression of genes, resulting in an increased risk of breast cancer, which is one of the most frequent cancers among women.

Conclusion

There are some risks to be aware of, which followed the hypothesis that long IVF treatment process may lead to breast cancer among IVF candidates. Furthermore, the risk of breast cancer may be increased in those women with a positive family history and related inherited genes. Therefore, women candidates for IVF should be informed of the probable implications of the reproductive therapy techniques.

Pubertal Growth, IGF-1, and Windows of Susceptibility: Puberty and Future Breast Cancer Risk

PURPOSE

Risk markers for breast cancer include earlier onset of menarche (age at menarche [AAM]) and peak height velocity (PHV). Insulin-like growth factor-1 (IGF-1) is associated with pubertal milestones, as well as cancer risk. This study examined the relationships between pubertal milestones associated with breast cancer risk and hormone changes in puberty.

METHODS

This is a longitudinal study of pubertal maturation in 183 girls, recruited at ages 6-7, followed up between 2004 and 2018. Measures included age at onset of puberty, and adult height attained; PHV; AAM; adult height, and serum IGF-1, and estrone-to-androstenedione (E:A) ratio.

RESULTS

PHV was greatest in early, and least in late maturing girls; length of the pubertal growth spurt was longest in early, and shortest in late maturing girls. Earlier AAM was related to greater PHV. IGF-1 concentrations tracked significantly during puberty; higher IGF-1 was related to earlier age of PHV, earlier AAM, greater PHV, and taller adult height. Greater E:A ratio was associated with earlier AAM.

CONCLUSIONS

Factors driving the association of earlier menarche and pubertal growth with breast cancer risk may be explained through a unifying concept relating higher IGF-1 concentrations, greater lifelong estrogen exposure, and longer pubertal growth period, with an expanded pubertal window of susceptibility.

Pubertal mammary gland development is a key determinant of adult mammographic density

Mammographic density refers to the radiological appearance of fibroglandular and adipose tissue on a mammogram of the breast. Women with relatively high mammographic density for their age and body mass index are at significantly higher risk for breast cancer. The association between mammographic density and breast cancer risk is well-established, however the molecular and cellular events that lead to the development of high mammographic density are yet to be elucidated. Puberty is a critical time for breast development, where endocrine and paracrine signalling drive development of the mammary gland epithelium, stroma, and adipose tissue. As the relative abundance of these cell types determines the radiological appearance of the adult breast, puberty should be considered as a key developmental stage in the establishment of mammographic density. Epidemiological studies have pointed to the significance of pubertal adipose tissue deposition, as well as timing of menarche and thelarche, on adult mammographic density and breast cancer risk. Activation of hypothalamic-pituitary axes during puberty combined with genetic and epigenetic molecular determinants, together with stromal fibroblasts, extracellular matrix, and immune signalling factors in the mammary gland, act in concert to drive breast development and the relative abundance of different cell types in the adult breast. Here, we discuss the key cellular and molecular mechanisms through which pubertal mammary gland development may affect adult mammographic density and cancer risk.

Adolescent alcohol, nuts, and fiber: combined effects on benign breast disease risk in young women

Adolescent drinking is associated with higher risks of proliferative benign breast disease (BBD) and invasive breast cancer (BC). Furthermore, adolescent nut and fiber consumptions are associated with lower risks of benign lesions and premenopausal BC. We hypothesize that diet (nuts, fiber) may mitigate the elevated BBD risk associated with alcohol. A prospective cohort of 9031 females, 9-15 years at baseline, completed questionnaires in 1996-2001, 2003, 2005, 2007, 2010, 2013, and 2014. Participants completed food frequency questionnaires in 1996-2001. In 2005, participants (>=18 years) began reporting biopsy-confirmed BBD (N = 173 cases). Multivariable logistic regression estimated associations between BBD and cross-classified intakes (14-17 years) of alcohol and peanut butter/nuts (separately, total dietary fiber). Only 19% of participants drank in high school; drinking was associated with elevated BBD risk (OR = 1.75, 95% CI: 1.20-2.56; p = 0.004) compared to nondrinkers. Participants consuming any nuts/butter had lower BBD risk (OR = 0.64, 95% CI: 0.45-0.90; p = 0.01) compared to those consuming none. Participants in top 75% fiber intake had lower risk (OR = 0.57, 95% CI: 0.40-0.81; p = 0.002) compared to bottom quartile. Testing our hypothesis that consuming nuts/butter mitigates the elevated alcohol risk, analyzing alcohol and nuts combined found that those who consumed both had lower risk (RR = 0.47, 95% CI: 0.24-0.89; p = 0.02) compared to drinkers eating no nuts. Our analysis of alcohol and fiber together did not demonstrate risk mitigation by fiber. For high school females who drink, their BBD risk may be attenuated by consuming nuts. Due to modest numbers, future studies need to replicate our findings in adolescent/adult females. However, high school students may be encouraged to eat nuts and fiber, and to avoid alcohol, to reduce risk of BBD and for general health benefits.

Body shape trajectories and risk of breast cancer: results from the SUN ('Seguimiento Universidad De Navarra') Project

OBJECTIVE

The aim of this study was to assess body shape trajectories in childhood and midlife in relation to subsequent risk of breast cancer (BC) in a Mediterranean cohort.

DESIGN

The 'Seguimiento Universidad de Navarra' (SUN) Project is a dynamic prospective cohort study of university graduates initiated in 1999. With a group-based modelling approach, we assessed body shape trajectories from age 5 to 40 years. Multivariable Cox regression models were used to estimate the hazard ratio (HR) for BC after the age of 40 years according to the body shape trajectory.

SETTING

City of Pamplona, in the North of Spain.

PARTICIPANTS

6498 women with a mean age of 40 years (sd 9).

RESULTS

We identified four distinct body shape trajectories ('childhood lean-midlife increase' (19·9 %), 'childhood medium-midlife stable' (53 %), 'childhood heavy-midlife stable' (21 %) and 'childhood heavy-midlife increase' (6·1 %)). Among 54 978 women-years of follow-up, we confirmed eighty-two incident cases of BC. Women in the 'childhood lean-midlife increase' group showed a higher risk of BC (HR = 1·84, 95 % CI 1·11, 3·04) compared with women in the 'childhood medium-midlife stable' category. This association was stronger for postmenopausal BC (HR = 2·42, 95 % CI 1·07, 5·48).

CONCLUSIONS

Our results suggest a role for lifetime adiposity in breast carcinogenesis.

Hypothalamic and Cell-Specific Transcriptomes Unravel a Dynamic Neuropil Remodeling in Leptin-Induced and Typical Pubertal Transition in Female Mice

Epidemiological and genome-wide association studies (GWAS) have shown high correlation between childhood obesity and advance in puberty. Early age at menarche is associated with a series of morbidities, including breast cancer, cardiovascular diseases, type 2 diabetes, and obesity. The adipocyte hormone leptin signals the amount of fat stores to the neuroendocrine reproductive axis via direct actions in the brain. Using mouse genetics, we and others have identified the hypothalamic ventral premammillary nucleus (PMv) and the agouti-related protein (AgRP) neurons in the arcuate nucleus (Arc) as primary targets of leptin action in pubertal maturation. However, the molecular mechanisms underlying leptin's effects remain unknown. Here we assessed changes in the PMv and Arc transcriptional program during leptin-stimulated and typical pubertal development using overlapping analysis of bulk RNA sequecing, TRAP sequencing, and the published database. Our findings demonstrate that dynamic somatodendritic remodeling and extracellular space organization underlie leptin-induced and typical pubertal maturation in female mice.

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MBH DEGs between lean and Lep^ob mice are highly represented in development

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Short-term leptin to Lep^ob mice alters MBH DEGs associated with reproduction

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PMv/Arc LepRb DEGs between lean and Lep^ob mice are abundant in extracellular space

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DEGs in developing PMv/Arc are conspicuous in extracellular and neuropil remodeling

Body size, silhouette trajectory and the risk of breast cancer in a Moroccan case-control study

BACKGROUND

There is convincing evidence demonstrating that body size characteristics such as adiposity and height are associated with breast cancer in westernized countries. However, little is known about this relationship in North African countries currently undergoing nutritional transition and industrialization. The aim of this study was to explore associations between various body size characteristics, silhouette trajectories and the risk of breast cancer among Moroccan women.

METHODS

In this case-control study conducted in the Fez region (2016-2017), detailed measures of body size were collected for 300 cases of breast cancer and 300 matched controls. Unconditional logistic regression was used to assess the association between body size and breast cancer risk adjusting for confounding factors.

RESULTS

Higher waist circumference and hip circumference were positively associated with breast cancer risk in pre- (highest [T3] vs. lowest tertile [T1]: OR = 2.92, 95% confidence intervals [CI]: 1.33-6.42; OR = 3.00, 95% CI: 1.42-6.33, respectively) and post-menopausal women (T3 vs. T1: OR = 4.46, 95% CI: 1.86-10.66; OR = 4.08, 95% CI: 1.76-9.42, respectively). Body shape at younger ages (6-11 years) was inversely associated with the risk of breast cancer in premenopausal women (large vs. lean silhouette: OR = 0.31, 95% CI: 0.12-0.80). Women with the greatest increase in body shape trajectory had higher risk for both pre- and post-menopausal breast cancer (T3 vs. T1: OR = 2.74, 95% CI: 1.03-7.26; OR = 3.56, 95% CI: 1.34-9.44, respectively).

CONCLUSION

Our findings suggest that adiposity, body shape at younger ages, and silhouette trajectory may play a role in the development of pre- and post-menopausal breast cancer among Moroccan women. Larger-scale prospective studies are needed to confirm our findings and to explore these associations with breast cancer subtypes.

Maternal pre-pregnancy obesity and timing of puberty in sons and daughters: a population-based cohort study

Background

In many countries, an increased prevalence of obesity in pregnancy has coincided with a declining pubertal age. We aimed to explore the potential effect of maternal pre-pregnancy overweight and obesity on timing of puberty in sons and daughters.

Methods

Between 2012 and 2018, 15 819 of 22 439 invited children from the Danish National Birth Cohort, born 2000–03, provided half-yearly information from the age of 11 years on the pubertal milestones: Tanner stages, voice break, first ejaculation, menarche, acne and axillary hair. We estimated adjusted mean monthly differences (with 95% confidence intervals) in age at attaining the pubertal milestones for children exposed to maternal pre-pregnancy obesity [body mass index (BMI) ≥30.0 kg/m²] or overweight (BMI 25.0 to 29.9 kg/m²) with normal weight (BMI 18.5 to 24.9 kg/m²) as reference. In mediation analysis, we explored whether childhood BMI at age 7 years mediated the associations.

Results

Maternal pre-pregnancy obesity was associated with earlier age at attaining most pubertal milestones in sons, and pre-pregnancy overweight and obesity were associated with earlier age at attaining all pubertal milestones in daughters. When combining all pubertal milestones, pre-pregnancy obesity [sons: −1.5 (−2.5, −0.4) months; daughters: −3.2 (−4.2, −2.1) months] and overweight [daughters only: −2.6 (−3.3, −1.8) months] were associated with earlier timing of puberty. The associations in sons were completely mediated by higher childhood BMI and partly so in daughters.

Conclusions

Maternal pre-pregnancy obesity appears to lower timing of puberty through childhood obesity in sons and mainly through other mechanisms in daughters.

Use of genetic variation to separate the effects of early and later life adiposity on disease risk: mendelian randomisation study

OBJECTIVE

To evaluate whether body size in early life has an independent effect on risk of disease in later life or whether its influence is mediated by body size in adulthood.

DESIGN

Two sample univariable and multivariable mendelian randomisation.

SETTING

The UK Biobank prospective cohort study and four large scale genome-wide association studies (GWAS) consortiums.

PARTICIPANTS

453 169 participants enrolled in UK Biobank and a combined total of more than 700 000 people from different GWAS consortiums.

EXPOSURES

Measured body mass index during adulthood (mean age 56.5) and self-reported perceived body size at age 10.

MAIN OUTCOME MEASURES

Coronary artery disease, type 2 diabetes, breast cancer, and prostate cancer.

RESULTS

Having a larger genetically predicted body size in early life was associated with an increased odds of coronary artery disease (odds ratio 1.49 for each change in body size category unless stated otherwise, 95% confidence interval 1.33 to 1.68) and type 2 diabetes (2.32, 1.76 to 3.05) based on univariable mendelian randomisation analyses. However, little evidence was found of a direct effect (ie, not through adult body size) based on multivariable mendelian randomisation estimates (coronary artery disease: 1.02, 0.86 to 1.22; type 2 diabetes:1.16, 0.74 to 1.82). In the multivariable mendelian randomisation analysis of breast cancer risk, strong evidence was found of a protective direct effect for larger body size in early life (0.59, 0.50 to 0.71), with less evidence of a direct effect of adult body size on this outcome (1.08, 0.93 to 1.27). Including age at menarche as an additional exposure provided weak evidence of a total causal effect (univariable mendelian randomisation odds ratio 0.98, 95% confidence interval 0.91 to 1.06) but strong evidence of a direct causal effect, independent of early life and adult body size (multivariable mendelian randomisation odds ratio 0.90, 0.85 to 0.95). No strong evidence was found of a causal effect of either early or later life measures on prostate cancer (early life body size odds ratio 1.06, 95% confidence interval 0.81 to 1.40; adult body size 0.87, 0.70 to 1.08).

CONCLUSIONS

The findings suggest that the positive association between body size in childhood and risk of coronary artery disease and type 2 diabetes in adulthood can be attributed to individuals remaining large into later life. However, having a smaller body size during childhood might increase the risk of breast cancer regardless of body size in adulthood, with timing of puberty also putatively playing a role.

Review: Diabetes, Obesity, and Cancer-Pathophysiology and Clinical Implications

Obesity and diabetes have both been associated with an increased risk of cancer. In the face of increasing obesity and diabetes rates worldwide, this is a worrying trend for cancer rates. Factors such as hyperinsulinemia, chronic inflammation, antihyperglycemic medications, and shared risk factors have all been identified as potential mechanisms underlying the relationship. The most common obesity- and diabetes-related cancers are endometrial, colorectal, and postmenopausal breast cancers. In this review, we summarize the existing evidence that describes the complex relationship between obesity, diabetes, and cancer, focusing on epidemiological and pathophysiological evidence, and also reviewing the role of antihyperglycemic agents, novel research approaches such as Mendelian Randomization, and the methodological limitations of existing research. In addition, we also describe the bidirectional relationship between diabetes and cancer with a review of the evidence summarizing the risk of diabetes following cancer treatment. We conclude this review by providing clinical implications that are relevant for caring for patients with obesity, diabetes, and cancer and provide recommendations for improving both clinical care and research for patients with these conditions.

The Relationship Between Quality of Life and Pubertal Timing in Adolescence: The Toyama Birth Cohort Study, Japan

PURPOSE

Although pubertal timing is gradually becoming earlier in Japan, support as for physical and mental health among children experiencing earlier puberty than their peers is inadequate. To better understand health and life satisfaction in seventh grade students (age 12-13 years), examination of relationships between health outcomes and pubertal timing, socioeconomic status, and lifestyle factors is necessary.

METHODS

Participants of the Toyama Birth Cohort Study (4,752 males and 4,740 females) answered questions regarding school year of onset of voice break for boys and menarche for girls, sleep quality, mental health difficulties, overall health, quality of life (QOL), and lifestyle. Relationship between health outcomes and pubertal timing was examined using binary logistic regression analysis.

RESULTS

Earlier pubertal timing was associated with four health-related outcomes. For poor sleep quality, the adjusted odds ratio (OR) of fourth grade males and crude OR of fifth grade females were statistically significant. Regarding mental health difficulties, the crude OR of fifth grade males and adjusted OR of fourth, fifth, and sixth grade females were statistically significant. Associations between poor overall health and fourth grade males and fourth or fifth grade females were observed. For poor QOL, the adjusted OR of fourth grade males and females was statistically significant.

CONCLUSIONS

Relationships between earlier pubertal timing and poor sleep quality, mental health difficulties, poor physical health, and poor QOL were observed. To improve children's quality of life, support from teachers and school doctors and nurses is needed-especially for children with earlier pubertal timing.

Age at menarche and risk of multiple sclerosis (MS): a systematic review and meta-analysis

BACKGROUND

Some studies have looked at the age at menarche and risk of Multiple Sclerosis (MS).We aimed to conduct a systematic review and meta-analysis to estimate a pooled odds ratio of developing MS by increasing age at menarche.

METHODS

We searched PubMed, Scopus, EMBASE, CINAHL, Web of Science, Ovid, google scholar and gray literature (references of references, congress abstracts) up to 10th April 2019.

RESULTS

The literature search found 312 articles. After eliminating duplicates, reviews, case reports and trials, 18 articles remained. Three articles were ultimately included in the final analysis. Two studies were from Iran, and one from Canada. The pooled odds ratio (OR) for increasing 1 year of age at menarche was 0.88 (95% CI:0.82-0.94), with no significant heterogeneity (I2 = 49%, p = 0.1). Mean age at menarche was significantly different between case and control groups (mean difference = - 0.22, 95% CI = -0.42,-0.02).

CONCLUSION

The result of this systematic review showed that the risk of MS decreases by increasing age at menarche.

Early-Life Growth and Benign Breast Disease

Using prospective data from the Early Determinants of Mammographic Density study (United States, 1959-2008, n = 1121), we examined the associations between maternal body size, birth size, and infant and early childhood growth during 3 time periods (0-4 months, 4-12 months, and 1-4 years) and benign breast disease (BBD) using multivariable logistic regression with generalized estimating equations. A total of 197 women (17.6%) reported receiving a diagnosis of BBD by a physician. Higher body mass index at age 7 years was inversely associated with BBD risk. Rapid weight gain from age 1 year to 4 years, defined as an increase of least 2 major percentiles (e.g., 5th, 10th, 25th, 50th, 75th, and 95th) relative to stable growth, defined as remaining within 2 percentiles, was also inversely associated with BBD (odds ratio (OR) = 0.51, 95% confidence interval (CI): 0.23, 1.15). In contrast, rapid weight gain in infancy was positively associated with BBD relative to stable growth (from 0 to 4 months, OR = 1.65, 95% CI: 1.04, 2.62; from 4 to 12 months, 1.85, 95% CI: 0.89, 3.85), independent of birth weight, which was not associated with BBD. Our results suggest that patterns of early-life weight gain are important to BBD risk. Thus, susceptibility to BBD, like susceptibility to breast cancer, might start in early life.

World Cancer Research Fund International: Continuous Update Project-systematic literature review and meta-analysis of observational cohort studies on physical activity, sedentary behavior, adiposity, and weight change and breast cancer risk

PURPOSE

The purpose of the present study was to systematically review the complex associations between energy balance-related factors and breast cancer risk, for which previous evidence has suggested different associations in the life course of women and by hormone receptor (HR) status of the tumor.

METHODS

Relevant publications on adulthood physical activity, sedentary behavior, body mass index (BMI), waist and hip circumferences, waist-to-hip ratio, and weight change and pre- and postmenopausal breast cancer risk were identified in PubMed up to 30 April 2017. Random-effects meta-analyses were conducted to summarize the relative risks across studies.

RESULTS

One hundred and twenty-six observational cohort studies comprising over 22,900 premenopausal and 103,000 postmenopausal breast cancer cases were meta-analyzed. Higher physical activity was inversely associated with both pre- and postmenopausal breast cancers, whereas increased sitting time was positively associated with postmenopausal breast cancer. Although higher early adult BMI (ages 18-30 years) was inversely associated with pre- and postmenopausal breast cancers, adult weight gain and greater body adiposity increased breast cancer risk in postmenopausal women, and the increased risk was evident for HR+ but not HR- breast cancers, and among never but not current users of postmenopausal hormones. The evidence was less consistent in premenopausal women. There were no associations with adult weight gain, inverse associations with adult BMI (study baseline) and hip circumference, and non-significant associations with waist circumference and waist-to-hip ratio that were reverted to positive associations on average in studies accounting for BMI. No significant associations were observed for HR-defined premenopausal breast cancers.

CONCLUSION

Better understanding on the impact of these factors on pre- and postmenopausal breast cancers and their subtypes along the life course is needed.

Pubertal development after unintended intrauterine exposure to oral contraceptives: a nationwide cohort study

OBJECTIVE

To study the associations between exposure to oral contraceptives before conception and early in pregnancy and pubertal timing in boys and girls.

DESIGN

Population-based cohort study.

SETTING

Not applicable.

PATIENT(S)

Overall, 15,800 children (70%) born during 2000-2003 into the Danish National Birth Cohort were categorized according to maternal use of combined oral contraceptive pills or progestin-only pills reported around gestational week 17: no exposure (reference), exposure 4 months before conception, and exposure in early pregnancy. Children self-assessed pubertal status using Web-based questionnaires from 11 years and biannually throughout puberty.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Adjusted mean age differences (months) for attaining individual pubertal milestones and overall pubertal timing. Proportion mediated by prepubertal body mass index.

RESULT(S)

In boys, intrauterine exposure to oral contraceptives showed a tendency toward slightly earlier mean age for voice break (months, -3.8; 95% confidence interval [CI] -6.5, -1.0) and first ejaculation (months, -2.9; 95% CI -5.9, 0.1) and a mean difference of -1.4 months (95% CI -3.3, 0.4) for overall pubertal timing. Girls with intrauterine exposure tended to have slightly earlier age at menarche (months, -1.9; 95% CI -4.0, 0.3) and Tanner breast stages and had a mean difference of -0.9 months (95% CI -2.7, 1.0) for overall pubertal timing. Exposure before conception was not associated with pubertal timing. Prepubertal body mass index did not play a mediating role.

CONCLUSION(S)

This study shows some evidence that intrauterine exposure to oral contraceptives might slightly affect pubertal timing.

Dietary intake from birth through adolescence in relation to risk of benign breast disease in young women

PURPOSE

Nutritional factors during different periods in life impact breast cancer risk. Because benign breast disease (BBD) is a well-established risk factor for breast cancer, we investigated childhood nutrition from birth through age 14 year and subsequent BBD.

METHODS

A prospective cohort study of 9031 females, 9-15 year at baseline, completed questionnaires (including heights, weights) annually from 1996 to 2001, in 2003, 2005, 2007, 2010, 2013 and 2014. In 1996, mothers reported infant feeding practices during their daughters first year of life. Beginning in 1996, participants completed annual food frequency questionnaires. In 2005, participants (18 year +) began reporting whether they had ever been diagnosed with biopsy-confirmed BBD (N = 173 cases). Multivariable logistic regression models estimated associations between childhood nutrition and BBD, adjusted for maternal breast disease and childhood body size factors.

RESULTS

Although no infant nutrition factors were associated with biopsy-confirmed BBD, certain adolescent dietary factors were. A multivariable model simultaneously included the most important diet and body size factors from different age periods: higher BBD risk was associated with greater age 10 year consumption of animal (non-dairy, energy-adjusted) fat (OR 2.27, p < .02, top vs. bottom quartiles) and with lower 14 year consumption of nuts/peanut butter (OR 0.60, p = .033, top vs. bottom quartiles).

CONCLUSION

Greater intake of animal (non-dairy) fat at 10 year and lower intake of nuts/peanut butter at 14 year were independently associated with higher BBD risk. These dietary factors appeared to operate on BBD risk independent of childhood growth (gestational weight gain, childhood BMI and height, adolescent height growth velocity), young adult height and BMI, and family history.

Severe acne and risk of breast cancer

PURPOSE

Hormonal imbalance early in life is thought to be associated with breast cancer risk. Severe acne may arise from hormonal imbalance and could serve as an indicator of increased breast cancer risk. We explored whether severe acne was associated with incident breast cancer.

METHODS

We used data from the Sister Study, a large (n = 50,884) prospective cohort of women who had a sister diagnosed with breast cancer, but who were free of breast cancer themselves at baseline. Participants completed a structured questionnaire that included demographics, lifestyle factors, and medical history, including any diagnosis of severe acne. Adjusted Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the association of severe acne and breast cancer (invasive disease or ductal carcinoma in situ).

RESULTS

During an average of 8.4 years of follow-up, 3049 breast cancer cases were diagnosed. Ever being diagnosed with severe acne was associated with a higher risk of breast cancer (HR 1.23; 95% CI 0.98, 1.54), particularly in women who were diagnosed prior to age 18 years (HR 1.40; 95% CI 1.04, 1.90). Results were similar when limited to invasive cancers.

CONCLUSIONS

Our study supports a non-significant positive association between severe acne-a potential marker of hormonal imbalance-and breast cancer risk. These findings suggest that severe acne, when considered along with other risk factors, could help to identify women who may be at a higher risk of breast cancer.

Adolescent caffeine consumption and mammographic breast density in premenopausal women

PURPOSE

Previous studies suggest that coffee and caffeine intake may be associated with reduced breast cancer risk. To date, there is limited and inconsistent epidemiologic evidence for associations of adolescent diet with mammographic breast density, a strong and consistent predictor of breast cancer. We investigated the association of adolescent caffeine intake with mammographic density in premenopausal women.

METHODS

This study included 751 cancer-free women within the Nurses' Health Study II cohort. Percent breast density (PD), absolute dense (DA) and non-dense areas (NDA) were measured from digitized film mammograms using a computer-assisted thresholding technique; all measures were square root-transformed. Energy-adjusted adolescent caffeine intake was estimated using the data from a food frequency questionnaire. Information regarding breast cancer risk factors was obtained from questionnaires closest to the mammogram date. We used generalized linear regression to quantify associations of caffeine intake with breast density measures.

RESULTS

In multivariable analyses, adolescent caffeine intake was not associated with any of the density phenotypes (caffeine 4th vs. 1st quartile: β = - 1.27, 95% CI - 4.62; 2.09, p-trend = 0.55 for percent density; β = - 0.21, 95% CI - 0.76, 0.34, p-trend = 0.65 for absolute dense area, and β = 0.23, 95% CI - 0.28, 0.74, p-trend = 0.50 for non-dense area). Additional adjustment of the models for body mass index at age 18 resulted in attenuation of the risk estimates.

CONCLUSIONS

Our findings do not support the hypothesis that adolescent caffeine intake is associated with premenopausal mammographic breast density.

Neuroanatomical Framework of the Metabolic Control of Reproduction

A minimum amount of energy is required for basic physiological processes, such as protein biosynthesis, thermoregulation, locomotion, cardiovascular function, and digestion. However, for reproductive function and survival of the species, extra energy stores are necessary. Production of sex hormones and gametes, pubertal development, pregnancy, lactation, and parental care all require energy reserves. Thus the physiological systems that control energy homeostasis and reproductive function coevolved in mammals to support both individual health and species subsistence. In this review, we aim to gather scientific knowledge produced by laboratories around the world on the role of the brain in integrating metabolism and reproduction. We describe essential neuronal networks, highlighting key nodes and potential downstream targets. Novel animal models and genetic tools have produced substantial advances, but critical gaps remain. In times of soaring worldwide obesity and metabolic dysfunction, understanding the mechanisms by which metabolic stress alters reproductive physiology has become crucial for human health.

Maternal Smoking During Pregnancy and Timing of Puberty in Sons and Daughters: A Population-Based Cohort Study

Because early puberty has been linked to diseases later in life, identification of modifiable causes of early puberty is of interest. We explored the possible associations between maternal smoking during pregnancy and pubertal development in sons and daughters. Between 2012 and 2017, 15,819 children from the Danish National Birth Cohort, born during 2000-2003, provided half-yearly information on puberty from the age of 11 years. We estimated adjusted age differences (in months) at attaining various pubertal milestones, including Tanner stages, per 10 daily cigarettes smoked in the first trimester of gestation. In sons, exposure to smoking in utero was associated with earlier genital development (Tanner 2, -1.3 months, 95% confidence interval (CI): -2.5, 0.0; Tanner 5, -3.7 months, 95% CI: -5.3, -2.0), pubic hair development (Tanner 2, -1.8 months, 95% CI: -2.9, -0.6; Tanner 5, -2.9 months, 95% CI: -4.2, -1.7), and voice break (-2.4 months, 95% CI: -3.6, -1.3). In daughters, maternal smoking was associated with earlier breast development (Tanner 2, -3.4 months, 95% CI: -5.3, -1.5; Tanner 5, -4.7 months, 95% CI: -6.5, -2.9), pubic hair development stages 3-5 (Tanner 5, -2.5 months, 95% CI: -4.1, -1.0), and menarche (-3.1 months, 95% CI: -4.0, -2.3). Fetal exposure to tobacco smoke might advance timing of puberty in boys and girls.

Timing of puberty in boys and girls: A population-based study

BACKGROUND

A secular trend towards earlier puberty has been observed in girls, while a similar trend has been more uncertain in boys. We estimated current ages at pubertal development in both boys and girls.

METHODS

In this population-based cohort study, 14 759 of 22 439 invited boys and girls born from 2000 to 2003 in the Danish National Birth Cohort gave half-yearly self-reported information on puberty from the age of 11.5 years and throughout puberty. This late start of follow-up limits the estimation of age at onset of puberty but not later pubertal milestones. We estimated mean age at attaining the following pubertal milestones in years with 95% confidence intervals (CI): age at menarche, voice break, first ejaculation of semen and Tanner stages for pubic hair development and breast development or genital development. Further, the difference in mean age at menarche between mothers and daughters was estimated.

RESULTS

In boys, voice break occurred at 13.1 (95% CI 13.0, 13.1) years, first ejaculation of semen occurred at 13.4 (95% CI 13.3, 13.4) years, and Tanner Genital Stage 5 occurred at 15.6 (95% CI 15.5, 15.6) years. In girls, age at menarche occurred at 13.0 (95% CI 13.0, 13.1) years and Tanner Breast Stage 5 occurred at 15.8 (95% CI 15.7, 15.9) years. Daughters had menarche 3.6 (95% CI 3.1, 4.2) months earlier than their mothers had.

CONCLUSION

These data indicate that age at menarche has declined and to some extent support a decline in age at attaining other markers of pubertal development among boys.

Acetaminophen (Paracetamol) Exposure During Pregnancy and Pubertal Development in Boys and Girls From a Nationwide Puberty Cohort

This study explored the association between exposure to acetaminophen during pregnancy and pubertal development using data from 15,822 boys and girls in the longitudinal Puberty Cohort, nested within the Danish National Birth Cohort. Use of acetaminophen was reported 3 times during pregnancy and 6 months postpartum. In total, 54% of mothers indicated use at least once during pregnancy. Between 2012 and 2017, sons and daughters provided information on a wide range of pubertal milestones-including Tanner stages, axillary hair growth, and age at menarche or voice break and first ejaculation-every 6 months from 11 years of age until full sexual maturation. Data were analyzed using a regression model for interval-censored data, providing adjusted mean monthly differences in age at attaining the pubertal milestones according to intrauterine cumulative (weeks) and trimester-specific acetaminophen exposure. Our results suggested a tendency towards slightly earlier attainment of almost all studied markers of female pubertal development with increasing number of weeks of exposure (i.e., about 1.5-3 months earlier age at pubic hair, axillary hair, and acne development comparing unexposed with those prenatally exposed for more than 12 weeks). Male pubertal development had no strong association with acetaminophen exposure.

Pre- and perinatal factors and incidence of breast cancer in the Black Women's Health Study

PURPOSE

The purpose of the study was to investigate the association between pre- or perinatal factors and breast cancer risk among African American women.

METHODS

Participants in the Black Women's Health Study, a prospective cohort of 59,000 African American women, reported birth weight, preterm birth, twin or triplet status, maternal age at birth, birth order, and having been breastfed during infancy at various times during follow-up from 1997 to 2015. Numbers of incident cases ranged from 312 for breastfed analyses to 1,583 for twin or triplet analyses. Using multivariable Cox proportional hazards regression, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between each factor and breast cancer risk overall and by estrogen receptor (ER) status.

RESULTS

Compared to birth weights of 5 lbs. 8 oz.-8 lbs. 13 oz., low (< 5 lbs. 8 oz.) and high (> 8 lbs. 13 oz.) birth weights were associated with increased breast cancer risk; HRs (95% CI) were 1.19 (0.98-1.44) and 1.26 (0.97-1.63), respectively. Associations were similar by ER status. Having been born to a mother aged ≥ 35 years versus < 20 years was associated with risk of ER+ (HR 1.59, 95% CI 1.10-2.29), but not ER- breast cancer. Other perinatal factors were not associated with breast cancer.

CONCLUSION

African American women with a low or high birth weight or born to older mothers may have increased breast cancer risk. Trends towards delayed child birth and higher birth weights, coupled with disproportionately high rates of low birth weight among African Americans, may contribute to increases in breast cancer incidence.

Age-specific breast cancer risk by body mass index and familial risk: prospective family study cohort (ProF-SC)

BACKGROUND

The association between body mass index (BMI) and risk of breast cancer depends on time of life, but it is unknown whether this association depends on a woman's familial risk.

METHODS

We conducted a prospective study of a cohort enriched for familial risk consisting of 16,035 women from 6701 families in the Breast Cancer Family Registry and the Kathleen Cunningham Foundation Consortium for Research into Familial Breast Cancer followed for up to 20 years (mean 10.5 years). There were 896 incident breast cancers (mean age at diagnosis 55.7 years). We used Cox regression to model BMI risk associations as a function of menopausal status, age, and underlying familial risk based on pedigree data using the Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA), all measured at baseline.

RESULTS

The strength and direction of the BMI risk association depended on baseline menopausal status (P < 0.001); after adjusting for menopausal status, the association did not depend on age at baseline (P = 0.6). In terms of absolute risk, the negative association with BMI for premenopausal women has a much smaller influence than the positive association with BMI for postmenopausal women. Women at higher familial risk have a much larger difference in absolute risk depending on their BMI than women at lower familial risk.

CONCLUSIONS

The greater a woman's familial risk, the greater the influence of BMI on her absolute postmenopausal breast cancer risk. Given that age-adjusted BMI is correlated across adulthood, maintaining a healthy weight throughout adult life is particularly important for women with a family history of breast cancer.

Association of Body Mass Index and Age With Subsequent Breast Cancer Risk in Premenopausal Women

Importance

The association between increasing body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) and risk of breast cancer is unique in cancer epidemiology in that a crossover effect exists, with risk reduction before and risk increase after menopause. The inverse association with premenopausal breast cancer risk is poorly characterized but might be important in the understanding of breast cancer causation.

Objective

To investigate the association of BMI with premenopausal breast cancer risk, in particular by age at BMI, attained age, risk factors for breast cancer, and tumor characteristics.

Design, Setting, and Participants

This multicenter analysis used pooled individual-level data from 758 592 premenopausal women from 19 prospective cohorts to estimate hazard ratios (HRs) of premenopausal breast cancer in association with BMI from ages 18 through 54 years using Cox proportional hazards regression analysis. Median follow-up was 9.3 years (interquartile range, 4.9-13.5 years) per participant, with 13 082 incident cases of breast cancer. Participants were recruited from January 1, 1963, through December 31, 2013, and data were analyzed from September 1, 2013, through December 31, 2017.

Exposures

Body mass index at ages 18 to 24, 25 to 34, 35 to 44, and 45 to 54 years.

Main Outcomes and Measures

Invasive or in situ premenopausal breast cancer.

Results

Among the 758 592 premenopausal women (median age, 40.6 years; interquartile range, 35.2-45.5 years) included in the analysis, inverse linear associations of BMI with breast cancer risk were found that were stronger for BMI at ages 18 to 24 years (HR per 5 kg/m2 [5.0-U] difference, 0.77; 95% CI, 0.73-0.80) than for BMI at ages 45 to 54 years (HR per 5.0-U difference, 0.88; 95% CI, 0.86-0.91). The inverse associations were observed even among nonoverweight women. There was a 4.2-fold risk gradient between the highest and lowest BMI categories (BMI≥35.0 vs <17.0) at ages 18 to 24 years (HR, 0.24; 95% CI, 0.14-0.40). Hazard ratios did not appreciably vary by attained age or between strata of other breast cancer risk factors. Associations were stronger for estrogen receptor-positive and/or progesterone receptor-positive than for hormone receptor-negative breast cancer for BMI at every age group (eg, for BMI at age 18 to 24 years: HR per 5.0-U difference for estrogen receptor-positive and progesterone receptor-positive tumors, 0.76 [95% CI, 0.70-0.81] vs hormone receptor-negative tumors, 0.85 [95% CI: 0.76-0.95]); BMI at ages 25 to 54 years was not consistently associated with triple-negative or hormone receptor-negative breast cancer overall.

Conclusions and Relevance

The results of this study suggest that increased adiposity is associated with a reduced risk of premenopausal breast cancer at a greater magnitude than previously shown and across the entire distribution of BMI. The strongest associations of risk were observed for BMI in early adulthood. Understanding the biological mechanisms underlying these associations could have important preventive potential.

Age of Menarche in a Longitudinal US Cohort

STUDY OBJECTIVE

Menarche is a critical milestone in a woman's life, and historically has been determined using several approaches. The goals of this study were to: (1) determine age at menarche from multiple reports of parents and adolescent participants in a prospective study; (2) examine factors affecting age at menarche; and (3) determine correlates of menarche and pubertal tempo.

DESIGN

Longitudinal observational study.

SETTING

Three sites of the Breast Cancer and the Environment Research Program.

PARTICIPANTS

Girls enrolled at 6-8 years of age.

INTERVENTIONS AND MAIN OUTCOME MEASURES

Parental and participant reported age of menarche, and tempo of puberty.

RESULTS

There were 946 girls who were assigned an age of menarche. The correlation between parent and participant reports was high (Spearman R = 0.799, P < .001), and the difference was insignificant. Median age at menarche overall was 12.25 years. Compared with black participants, Hispanic girls were more likely to have menarche earlier, whereas white and Asian girls were more likely to have menarche later. Age of menarche was highly correlated with age of breast development (Spearman R = 0.547; P < .001), and inversely with body mass index (Spearman R = -0.403; P < .001). Tempo (interval of age of breast development to menarche) was slower in those with earlier breast development.

CONCLUSION

Parental and adolescent reports of menarche are highly correlated. Earlier breast maturation was associated with slower tempo through puberty. Body mass index had a greater effect on age at menarche than did race and ethnicity.

Self-assessment of pubertal development in a puberty cohort

Background We evaluated the inter-rater agreement between self-assessed Tanner staging and clinical examination and the intra-individual agreement of self-assessed information on various puberty markers in late adolescents from the longitudinal nationwide Puberty Cohort, a sub-cohort of the Danish National Birth Cohort (DNBC). Methods We invited 715 children from the ongoing Puberty Cohort between June 2016 and January 2017. In total, 366 children (51%) returned an add-on questionnaire identical to the questionnaire used to collect information on puberty markers, including Tanner staging, in the Puberty Cohort. Of these, 197 (54%) also participated in a clinical examination with Tanner staging. We used percentage agreement and weighted kappa statistics to evaluate the inter-rater and intra-individual agreement. Results Due to late entry, more than 75% of children were Tanner stage 4 or above at clinical examination. In girls, the inter-rater agreement for pubic hair and breast staging was 54% and 52%, respectively, yielding weighted kappas of fair strength. In boys, pubic hair and genital staging agreed in 55% and 33%, respectively, corresponding to weighted kappas of fair to moderate strength. Boys tended to underestimate genitalia staging consistently. The intra-individual agreement on Tanner staging was 75-77% in girls and 69% in boys, whereas the intra-individual agreement on axillary hair and acne was above 92%. Conclusions Self-assessment of late stages of pubertal development may be misclassified, leading to random errors in studies of puberty timing. However, self-assessment continues to serve as an important time- and cost-saving tool in large prospective puberty cohorts.

Life course evolution of body size and breast cancer survival in the E3N cohort

Although adult obesity has been associated with poor breast cancer survival, data on adiposity at different periods in life and its lifelong evolution are scarce. Our aims were to assess the associations between breast cancer survival and body size during childhood, puberty and early adulthood and body size trajectories from childhood to adulthood. Self-assessed body size at age 8, at puberty, at age 20-25 and at age 35-40 and trajectories of body size of 4,662 breast cancer survivors from the prospective E3N cohort were studied in relation to risk of death from any cause, death from breast cancer and second invasive cancer event using multivariate Cox regression models. Four trajectories of body size were identified (T1 "moderate increase," T2 "stable/low increase," T3 "increase at puberty" and T4 "constantly high"). Compared with stable body size, an increase in body size during adult life was associated with an increased risk of death from any cause (HR T1 vs. T2 = 1.27; 95% CI = 1.01-1.60) and an increased risk of second invasive cancer event (HR T1 vs. T2 = 1.25; 95% CI = 1.06-1.47). Silhouettes at various ages were not associated with survival. Our results suggest that the evolution of body size from childhood to adulthood has a long-term influence on breast cancer survival. Although these results need to be confirmed, this work sheds light on the need to combine lifelong approaches to current BMI to better identify breast cancer survivors who are at higher risk of recurrence or second primary cancer, or of death.

Adiposity at Age 10 and Mammographic Density among Premenopausal Women

Although childhood adiposity is inversely associated with breast cancer risk, the association of childhood adiposity with mammographic density in premenopausal women has not been adequately studied. We analyzed data from 365 premenopausal women who came in for screening mammography at Washington University (St. Louis, MO) from 2015 to 2016. Body size at age 10 was self-reported using somatotype pictogram. Body mass index (BMI) at age 10 was imputed using data from Growing Up Today Study. Volpara software was used to evaluate volumetric percent density (VPD), dense volume (DV), and nondense volume (NDV). Adjusted multivariable linear regression models were used to evaluate the associations between adiposity at age 10 and mammographic density measures. Adiposity at age 10 was inversely associated with VPD and positively associated with NDV. A 1 kg/m² increase in BMI at age 10 was associated with a 6.4% decrease in VPD, and a 6.9% increase in NDV (P < 0.001). Compared with women whose age 10 body size was 1 or 2, women with body size 3 or 4 had a 16.8% decrease in VPD and a 26.6% increase in NDV, women with body size 5 had a 32.2% decrease in VPD and a 58.5% increase in NDV, and women with body sizes ≥6 had a 47.8% decrease in VPD and a 80.9% increase in NDV (P < 0.05). The associations were attenuated, but still significant after adjusting for current BMI. Mechanistic studies to understand how childhood adiposity influences breast development, mammographic density, and breast cancer in premenopausal women are needed. Cancer Prev Res; 11(5); 287-94. ©2018 AACR.

Pubertal and adult windows of susceptibility to a high animal fat diet in Trp53-null mammary tumorigenesis

Premenopausal breast cancer is associated with increased animal fat consumption among normal weight, but not overweight women (Farvid et al., 2014). Our previous findings in obesity-resistant BALB/c mice similarly showed promotion of carcinogen-induced mammary tumorigenesis by a diet high in saturated animal fat (HFD). This effect was specific to pubertal versus adult HFD. This study identifies the effects of HFD during puberty versus adulthood in Trp53-null transplant BALB/c mice and investigates its mechanism of enhancing tumorigenesis. Either pubertal or adult HFD is sufficient to increase incidence of Trp53-null mammary tumors. Puberty-restricted HFD exposure promoted tumor cell proliferation, increased angiogenesis, and increased recruitment of total and M2 macrophages in epithelial tumors. Adult-restricted exposure to HFD similarly increased proliferation, angiogenesis, recruitment of total and M2 macrophages, and additionally reduced apoptosis. Adult HFD also increased incidence of spindle cell carcinomas resembling claudin-low breast cancer, and thus adult HFD in the Trp53-null transplantation system may be a useful model for human claudin low breast cancer. Importantly, these results on Trp53-null and our prior studies on DMBA-induced mammary tumorigenesis demonstrate a pubertal window of susceptibility to the promotional effects of HFD, indicating the potential of early life dietary intervention to reduce breast cancer risk.

Height and Body Size in Childhood, Adolescence, and Young Adulthood and Breast Cancer Risk According to Molecular Subtype in the Nurses' Health Studies

Height and body size in childhood and young adulthood have been consistently associated with breast cancer risk; whether associations differ across molecular subtypes is unclear. In a pooled analysis of the Nurses' Health Studies, we prospectively examined the association of four exposures: height, body mass index (BMI) at the age of 18 years, childhood and adolescent somatotypes, with breast cancer risk according to molecular subtypes defined by immunohistochemical markers. We used multivariable-adjusted Cox proportional hazards regression to estimate HRs and 95% confidence intervals (CI). We identified 2,983 luminal A, 1,281 luminal B, 318 HER2-enriched, 408 basal-like, and 128 unclassified tumors. Height was positively associated with all subtypes (Pheterogeneity = 0.78). BMI at the age of 18 (Pheterogeneity = 0.001), childhood (Pheterogeneity = 0.51), and adolescent somatotype (Pheterogeneity = 0.046) were inversely associated, but with differences in magnitude of association. BMI at the age of 18 of ≥25 kg/m(2) (compared with 20-21.9 kg/m(2)) was associated with a 52% decreased risk of HER2-enriched (HR, 0.48; 95% CI, 0.26-0.91; Ptrend < 0.0001) and 39% reduced risk of basal-like tumors (HR, 0.61; 95% CI, 0.36-1.02; Ptrend = 0.008). Compared with the lowest category, women in the highest adolescent body size category were 71% less likely to develop HER2-enriched (HR, 0.29; 95% CI, 0.10-0.85; Ptrend = 0.0005) and 60% less likely to develop basal-like (HR, 0.40; 95% CI, 0.17-0.95; Ptrend = 0.0008). Height was positively associated with risk of all breast cancer molecular subtypes. BMI at 18 years and childhood and adolescent were inversely associated with risk of most breast cancer molecular subtypes with somewhat stronger associations with HER2-enriched and basal-like subtypes. Cancer Prev Res; 9(9); 732-8. ©2016 AACR.

Is age at puberty associated with semen quality and reproductive hormones in young adult life?

The evidence is scarce on the association between age at puberty and semen quality. A cohort of 320 Danish men aged 18-21 years enrolled in the "Healthy Habits for Two" birth cohort provided self-reported data on pubertal indicators and delivered semen and blood samples. The results indicated an association between older age at pubertal development and lower semen quality and altered reproductive hormones concentrations as measured in young adult life. Men who had their first nocturnal emission, start of pubic hair growth and first voice break episode when older than 15 years had 37.0%, 45.0% and 32.7% lower sperm concentration; 37.8%, 44.2% and 29.1% lower total sperm count; 7.4%, 13.4% and 15.3% lower testosterone concentration; and 21.3%, 1.5% and 3.7% lower inhibin B concentration, respectively, compared with the men who were younger than 13 years at their first pubertal indicators. Only few of the results were statistically significant, but similar tendencies were seen in several of the reproductive parameters suggesting an association between the timing of pubertal development and reproductive health later in life.

Pubertal growth and adult height in relation to breast cancer risk in African American women

Adult height has been positively associated with breast cancer risk. The timing of pubertal growth-as measured by age at menarche and age at attained height-may also influence risk. We evaluated associations of adult height, age at attained height, and age at menarche with incidence of invasive breast cancer in 55,687 African American women in the prospective Black Women's Health Study. Over 20 years, 1,826 invasive breast cancers [1,015 estrogen receptor (ER) positive; 542 ER negative] accrued. We used multivariable Cox proportional hazards regression to estimate hazards ratios (HRs) and 95% confidence intervals (CIs) for associations with breast cancer overall and by ER status, mutually adjusted for the three factors of interest. Adult height was associated with increased risk of ER+ breast cancer (HR for ≥70 inches vs ≤63 inches: 1.44; 95% CI: 1.09, 1.89) but not ER- (corresponding HR: 1.16; 95% CI: 0.78, 1.71) (p heterogeneity = 0.34). HRs for attained height before age 13 versus age >17 were 1.30 (95% CI: 0.96, 1.76) for ER+ and 1.25 (95% CI: 0.80, 1.96) for ER- breast cancer. Results for age at menarche (≤11 vs ≥14 years) were similar for ER+ and ER- breast cancer (HR for breast cancer overall: 1.30; 95% CI: 1.12, 1.50). We confirmed height as a strong risk factor for ER+ breast cancer in African American women and identified early age at attained height as a risk factor for both ER+ and ER- breast cancer, albeit without statistical significance of the latter associations. While adult height and timing of pubertal growth are inter-related, our findings suggest that they may be independent risk factors for breast cancer.

The potential contribution of dietary factors to breast cancer prevention

Breast cancer (BC), the leading cancer in women, is increasing in prevalence worldwide, concurrent with western metabolic epidemics, that is, obesity, metabolic syndrome, and diabetes, and shares major risk factors with these diseases. The corresponding potential for nutritional contributions toward BC prevention is reviewed and related to critical stages in the life cycle and their implications for carcinogenic and pathometabolic trajectories. BC initiation potentially involves diet-related pro-oxidative, inflammatory, and procarcinogenic processes, that interact through combined lipid/fatty acid peroxidation, estrogen metabolism, and related DNA-adduct/depurination/mutation formation. The pathometabolic trajectory is affected by high estrogen, insulin, and growth factor cascades and resultant accelerated proliferation/progression. Anthropometric risk factors - high birth weight, adult tallness, adiposity/BMI, and weight gain - are often reflective of these trends. A sex-based nutritional approach targets women's specific risk in western obesogenic environments, associated with increasing fatness, estrogen metabolism, n-6 : n-3 polyunsaturated fatty acid ratio, and n-6 polyunsaturated fatty acid conversion to proinflammatory/carcinogenic eicosanoids, and effects of timing of life events, for example, ages at menarche, full-term pregnancy, and menopause. Recent large-scale studies have confirmed the effectiveness of the evidence-based recommendations against BC risk, emphasizing low-energy density diets, highly nutritious plant-based regimes, physical activity, and body/abdominal adiposity management. Better understanding of dietary inter-relationships with BC, as applied to food intake, selection, combination, and processing/preparation, and recommended patterns, for example, Mediterranean, DASH, plant-based, low energy density, and low glycemic load, with high nutrient/phytonutrient density, would increase public motivation and authoritative support for early/timely prevention, optimally merging with other dietary/health goals, for lifelong BC prevention.

The Premenopausal Breast Cancer Collaboration: A Pooling Project of Studies Participating in the National Cancer Institute Cohort Consortium

Breast cancer is a leading cancer diagnosis among premenopausal women around the world. Unlike rates in postmenopausal women, incidence rates of advanced breast cancer have increased in recent decades for premenopausal women. Progress in identifying contributors to breast cancer risk among premenopausal women has been constrained by the limited numbers of premenopausal breast cancer cases in individual studies and resulting low statistical power to subcategorize exposures or to study specific subtypes. The Premenopausal Breast Cancer Collaborative Group was established to facilitate cohort-based analyses of risk factors for premenopausal breast cancer by pooling individual-level data from studies participating in the United States National Cancer Institute Cohort Consortium. This article describes the Group, including the rationale for its initial aims related to pregnancy, obesity, and physical activity. We also describe the 20 cohort studies with data submitted to the Group by June 2016. The infrastructure developed for this work can be leveraged to support additional investigations. Cancer Epidemiol Biomarkers Prev; 26(9); 1360-9. ©2017 AACR.

Age at Pubertal Onset in Girls and Tobacco Smoke Exposure During Pre- and Postnatal Susceptibility Windows

BACKGROUND

Tobacco smoke contains known hormonally active chemicals and reproductive toxicants. Several studies have examined prenatal maternal smoking and offspring age at menarche, but few examined earlier pubertal markers, nor accounted for exposure during childhood. Our objective was to examine pre- and postnatal smoke exposure in relation to timing of early pubertal events.

METHODS

An ethnically diverse cohort of 1239 girls was enrolled at age 6-8 years old for a longitudinal study of puberty at three US sites. Girls participated in annual or semi-annual exams to measure anthropometry and Tanner breast and pubic hair stages. Prenatal and current tobacco smoke exposures, as well as covariates, were obtained from parent questionnaire. Cotinine was measured in urine collected at enrollment. Using accelerated failure time models, we calculated adjusted time ratios for age at pubertal onset (maturation stages 2 or higher) and smoke exposure.

RESULTS

Girls with higher prenatal (≥5 cigarettes per day) or secondhand smoke exposure had earlier pubic hair development than unexposed (adjusted time ratio: 0.92 [95% CI = 0.87, 0.97] and 0.94 [95% CI = 0.90, 0.97], respectively). Including both exposures in the same model yielded similar associations. Higher urinary cotinine quartiles were associated with younger age at breast and pubic hair onset in unadjusted models, but not after adjustment.

CONCLUSIONS

Greater prenatal and childhood secondhand smoke exposure were associated with earlier onset of pubic hair, but not breast, development. These exposures represent modifiable risk factors for early pubertal development that should be considered for addition to the extensive list of adverse effects from tobacco smoke.

Body size in early life and risk of breast cancer

Background

Body size in early life is inversely associated with adult breast cancer (BC) risk, but it is unclear whether the associations differ by tumor characteristics.

Methods

In a pooled analysis of two Swedish population-based studies consisting of 6731 invasive BC cases and 28,705 age-matched cancer-free controls, we examined the associations between body size in early life and BC risk. Self-reported body sizes at ages 7 and 18 years were collected by a validated nine-level pictogram (aggregated into three categories: small, medium and large). Odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated from multivariable logistic regression models in case-control analyses, adjusting for study, age at diagnosis, age at menarche, number of children, hormone replacement therapy, and family history of BC. Body size change between ages 7 and 18 were also examined in relation to BC risk. Case-only analyses were performed to test whether the associations differed by tumor characteristics.

Results

Medium or large body size at age 7 and 18 was associated with a statistically significant decreased BC risk compared to small body size (pooled OR (95% CI): comparing large to small, 0.78 (0.70–0.86), P_trend <0.001 and 0.72 (0.64–0.80), P_trend <0.001, respectively). The majority of the women (~85%) did not change body size categories between age 7 and 18 . Women who remained medium or large between ages 7 and 18 had significantly decreased BC risk compared to those who remained small. A reduction in body size between ages 7 and 18 was also found to be inversely associated with BC risk (0.90 (0.81–1.00)). No significant association was found between body size at age 7 and tumor characteristics. Body size at age 18 was found to be inversely associated with tumor size (P_trend = 0.006), but not estrogen receptor status and lymph node involvement. For all analyses, the overall inferences did not change appreciably after further adjustment for adult body mass index.

Conclusions

Our data provide further support for a strong and independent inverse relationship between early life body size and BC risk. The association between body size at age 18 and tumor size could be mediated by mammographic density.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-017-0875-9) contains supplementary material, which is available to authorized users.

Breast cancer risk prediction: an update to the Rosner-Colditz breast cancer incidence model

PURPOSE

To update and expand the Rosner-Colditz breast cancer incidence model by evaluating the contributions of more recently identified risk factors as well as predicted percent mammographic density (MD) to breast cancer risk.

METHODS

Using data from the Nurses' Health Study (NHS) and NHSII, we added adolescent somatotype (9 unit scale), vegetable intake (servings/day), breastfeeding (months), physical activity (MET-h/week), and predicted percent MD to the Rosner-Colditz model to determine whether these variables improved model discrimination. We evaluated all invasive as well as ER+/PR+, ER+/PR-, and ER-/PR- breast cancer.

RESULTS

In the NHS/NHSII, we accrued over 5200 cases of invasive breast cancer over more than 20 years of follow-up with complete data on the risk factors. Adolescent somatotype and predicted percent MD significantly improved the original Rosner-Colditz model for all invasive breast cancer (change in age-adjusted AUC = 0.020, p < 0.001). The relative risk (RR) of invasive breast cancer for a 4-unit increase in adolescent somatotype was 0.62 (95% CI 0.56, 0.70), whereas the RR for a 20-unit increase in predicted percent MD was 1.32 (95% CI 1.28, 1.36). Adolescent somatotype and predicted percent MD also significantly improved the ER+/PR+model (change in age-adjusted AUC = 0.020, p < 0.001) as well as the ER+/PR- model (change in age-adjusted AUC = 0.012, p = 0.007). Adolescent somatotype, predicted percent MD, breastfeeding, and vegetable intake improved the ER-/PR- model (change in AUC = 0.031, p < 0.0001). The RR of ER-/PR- disease for 5 vegetable servings/day increase was 0.83 (95% CI 0.70, 0.99), while the RR for every 12 months of breastfeeding was 0.88 (95% CI 0.77, 1.01). Physical activity did not improve risk classification in any model.

CONCLUSION

Adolescent somatotype and predicted percent MD significantly improved breast cancer risk classification using the Rosner-Colditz model. Further, risk factors specific to ER- disease, such as breastfeeding and vegetable intake, may also help improve risk prediction of this aggressive subtype.

Age at Menarche and Late Adolescent Adiposity Associated with Mammographic Density on Processed Digital Mammograms in 24,840 Women

Background: High mammographic density is strongly associated with increased breast cancer risk. Some, but not all, risk factors for breast cancer are also associated with higher mammographic density.Methods: The study cohort (N = 24,840) was drawn from the Research Program in Genes, Environment and Health of Kaiser Permanente Northern California and included non-Hispanic white females ages 40 to 74 years with a full-field digital mammogram (FFDM). Percent density (PD) and dense area (DA) were measured by a radiological technologist using Cumulus. The association of age at menarche and late adolescent body mass index (BMI) with PD and DA were modeled using linear regression adjusted for confounders.Results: Age at menarche and late adolescent BMI were negatively correlated. Age at menarche was positively associated with PD (P value for trend <0.0001) and DA (P value for trend <0.0001) in fully adjusted models. Compared with the reference category of ages 12 to 13 years at menarche, menarche at age >16 years was associated with an increase in PD of 1.47% (95% CI, 0.69-2.25) and an increase in DA of 1.59 cm² (95% CI, 0.48-2.70). Late adolescent BMI was inversely associated with PD (P < 0.0001) and DA (P < 0.0001) in fully adjusted models.Conclusions: Age at menarche and late adolescent BMI are both associated with Cumulus measures of mammographic density on processed FFDM images.Impact: Age at menarche and late adolescent BMI may act through different pathways. The long-term effects of age at menarche on cancer risk may be mediated through factors besides mammographic density. Cancer Epidemiol Biomarkers Prev; 26(9); 1450-8. ©2017 AACR.

Weight and weight changes in early adulthood and later breast cancer risk

Obesity is a well-established cause of postmenopausal breast cancer. However, early life adiposity is inversely associated with breast cancer incidence. To understand these conflicting relations, we use validated measures to assess adiposity in childhood and late adolescence, as well as weight change, in relation to total invasive breast cancer incidence and receptor subtypes. We conducted a prospective observational study among 74,177 women from the Nurses' Health Study from 1980-2012, with updated risk factors every 2 years during which 4,965 incident invasive breast cancers occurred. Overall, weight at age 18 was inversely associated with both premenopausal (HR per 30 kg = 0.52, 95% CI = 0.39-0.71) and postmenopausal (HR per 30 kg = 0.81, 95% CI = 0.72-0.92) breast cancer which was largely explained by adiposity at age 10. Long-term weight gain from age 18 both during premenopause and postmenopause were positively associated with postmenopausal breast cancer risk. However, premenopausal weight gain was not related to premenopausal breast cancer risk. Furthermore, weight gain since age 18 was positively associated with ER+/PR+ postmenopausal breast cancer (HR per 30 kg = 1.50, 95% CI = 1.36-1.65) but not ER+/PR- (HR per 30 kg = 0.96, 95% CI = 0.78-1.19) or ER-/PR- (HR per 30 kg = 1.16, 95% CI = 0.95-1.42) postmenopausal breast cancer. Overall, 17% of ER+/PR+ postmenopausal breast cancer and 14% of total postmenopausal breast cancer are attributable to weight gain of > 5 kg since age 18.