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This study examined the association of everyday discrimination with risk of obesity and the potential modifying effect of religious service attendance. Participants included Black, South Asian, and white women in three cohort studies that belong to the Study on Stress, Spirituality and Health. Logistic regression models estimated odds of obesity classification (BMI ≥ 30) relative to experiences of everyday discrimination. In initial pooled analyses, high levels of discrimination were related to increased odds of obesity. Race-specific analyses revealed marginal associations for white and South Asian women. Among Black women, high levels of discrimination and religious service attendance were both associated with higher odds of obesity. However, among women who attended religious services frequently, higher levels of everyday discrimination were associated with slightly lower odds of obesity. These findings underline the complex association between obesity and religion/spirituality, suggesting that higher levels of discrimination may uniquely activate religious resources or coping strategies. Findings highlight the need for additional studies to examine the impact of everyday discrimination on risk of obesity across racial/ethnic communities and how religious practices or coping strategies might affect these dynamics.

Protein intake plays an important role in maintaining the health status of older adults. However, few epidemiologic studies examined midlife protein intake in relation to healthy aging.

To increase research reproducibility, sharing of study data, analysis code, and use of standardized reporting are increasingly advocated. However, beyond reproducibility, few initiatives have addressed the integrity of how research is conducted before manuscripts are submitted. We describe a decades-long experience with a comprehensive approach based in an academic research community around prospective cohort studies that is aimed at promoting a culture of integrity in observational research. The approach includes prespecifying hypotheses and analysis plans, which are discussed in the research community and posted; presentation and discussion of analysis results; mandatory analysis code review by a programmer; review of concordance between analysis output and manuscripts by a technical reviewer; and checks of adherence to the process, including compliance with institutional review board requirements and reporting stipulations by the National Institutes of Health. The technical core is based in shared computing and analytic environments with long-term archiving. More than simply a list of rules, our approach promotes research integrity through integrated educational elements, making it part of the “hidden curriculum,” by fostering a sense of belonging, and by providing efficiency gains to the research community. Unlike reproducibility checklists, such long-term investments into research integrity require substantial and sustained funding for research personnel and computing infrastructure. Our experiences suggest avenues for how institutions, research communities, and funders involved in observational research can strengthen integrity within the research process.

Multiple dietary patterns have been associated with different diseases; however, their comparability to improve overall health has yet to be determined. Here, in 205,776 healthcare professionals from three US cohorts followed for up to 32 years, we prospectively assessed two mechanism-based diets and six diets based on dietary recommendations in relation to major chronic disease, defined as a composite outcome of incident major cardiovascular disease (CVD), type 2 diabetes and cancer. We demonstrated that adherence to a healthy diet was generally associated with a lower risk of major chronic disease (hazard ratio (HR) comparing the 90th with the 10th percentile of dietary pattern scores = 0.68–0.84). Participants with low insulinemic (HR = 0.68, 95% confidence interval (CI) = 0.67, 0.70), low inflammatory (HR = 0.70, 95% CI = 0.69, 0.72) or diabetes risk-reducing (HR = 0.77, 95% CI = 0.75, 0.79) diet had the largest risk reduction for incident major CVD, type 2 diabetes and cancer as a composite and individually. Similar findings were observed across gender and diverse ethnic groups. Our results suggest that dietary patterns associated with markers of hyperinsulinemia and inflammation and diabetes development may inform on future dietary guidelines for chronic disease prevention.

Beyond alcohol and coffee, the relationship between other dietary factors, including specific vegetables and fruits, and liver outcomes remains poorly understood.

ObjectivesTo identify indolepropionate (IPA)-predicting gut microbiota species, investigate potential diet–microbiota interactions, and examine the prospective associations of circulating IPA concentrations with type 2 diabetes (T2D) and coronary heart disease (CHD) risk in free-living individuals.DesignWe included 287 men from the Men’s Lifestyle Validation Study, a substudy of the Health Professionals Follow-Up Study (HPFS), who provided up to two pairs of faecal samples and two blood samples. Diet was assessed using 7-day diet records. Associations between plasma concentrations of tryptophan metabolites and T2D CHD risk were examined in 13 032 participants from Nurses’ Health Study (NHS), NHSII and HPFS.ResultsWe identified 17 microbial species whose abundance was significantly associated with plasma IPA concentrations. A significant association between higher tryptophan intake and higher IPA concentrations was only observed among men who had higher fibre intake and a higher microbial species score consisting of the 17 species (p-interaction<0.01). Dietary and plasma concentrations of tryptophan and most kynurenine pathway metabolites were positively associated with T2D risk (HRQ5 vs Q1ranged from 1.17 to 1.46) while a significant inverse association was found for IPA (HRQ5 vs Q1(95% CI) 0.70 (0.56 to 0.88)). No associations were found in CHD for any plasma tryptophan metabolites.ConclusionsSpecific microbial species and dietary fibre jointly predicted significantly higher circulating IPA concentrations at higher tryptophan intake. Dietary and plasma tryptophan, as well as its kynurenine pathway metabolites, demonstrated divergent associations from those for IPA, which was significantly predictive of lower risk of T2D.

BackgroundPolygenic risk score (PRS), calculated based on genome-wide association studies (GWASs), can improve breast cancer (BC) risk assessment. To date, most BC GWASs have been performed in individuals of European (EUR) ancestry, and the generalisation of EUR-based PRS to other populations is a major challenge. In this study, we examined the performance of EUR-based BC PRS models in Ashkenazi Jewish (AJ) women.MethodsWe generated PRSs based on data on EUR women from the Breast Cancer Association Consortium (BCAC). We tested the performance of the PRSs in a cohort of 2161 AJ women from Israel (1437 cases and 724 controls) from BCAC (BCAC cohort from Israel (BCAC-IL)). In addition, we tested the performance of these EUR-based BC PRSs, as well as the established 313-SNP EUR BC PRS, in an independent cohort of 181 AJ women from Hadassah Medical Center (HMC) in Israel.ResultsIn the BCAC-IL cohort, the highest OR per 1 SD was 1.56 (±0.09). The OR for AJ women at the top 10% of the PRS distribution compared with the middle quintile was 2.10 (±0.24). In the HMC cohort, the OR per 1 SD of the EUR-based PRS that performed best in the BCAC-IL cohort was 1.58±0.27. The OR per 1 SD of the commonly used 313-SNP BC PRS was 1.64 (±0.28).ConclusionsExtant EUR GWAS data can be used for generating PRSs that identify AJ women with markedly elevated risk of BC and therefore hold promise for improving BC risk assessment in AJ women.

Background: Higher levels of endogenous sex steroid hormones are associated with increased risks of breast cancer in postmenopausal women. Data for premenopausal women are sparse, in part because of the complexity of measuring hormone levels that vary cyclically. We prospectively evaluated associations between plasma sex hormone levels and breast cancer risk among premenopausal women in a case-control study nested within the Nurses' Health Study II. Methods: From 1996 to 1999, blood samples were collected from 18 521 premenopausal women during the early follicular and mid-luteal phases of their menstrual cycles. A total of 197 cases of breast cancer were diagnosed among these women after blood collection and before June 1, 2003; these case subjects were matched to 394 control subjects. Logistic regression models, controlling for breast cancer risk factors, were used to calculate relative risks (RRs) and 95% confidence intervals (CIs). All statistical tests were two-sided. Results: Women in the highest (versus the lowest) quartiles of follicular total and free estradiol levels had statistically significantly increased risks of breast cancer (RR = 2.1 [95% CI = 1.1 to 4.1], [P.sub.trend] = .08, and RR = 2.4 [95% CI = 1.3 to 4.5], [P.sub.trend] = .01, respectively); the associations were stronger for invasive breast cancer and for estrogen and progesterone receptor-positive (ER+/PR+) tumors. Luteal estradiol levels were not associated with breast cancer risk. Higher levels of total and free testosterone and androstenedione in both menstrual cycle phases were associated with modest, non-statistically significant increases in overall risk of breast cancer and with stronger, statistically significant increases in risks of invasive and ER+/PR+ cancers (e.g., RR of invasive cancers for the top [versus bottom] quartile of luteal total testosterone levels = 2.0 [95% CI = 1.1 to 3.6], [P.sub.trend] = .05, and RR of ER+/PR+ cancers = 2.9 [95% CI = 1.4 to 6.0], [P.sub.trend] = .02). Levels of estrone, estrone sulfate, progesterone, and sex hormone-binding globulin were not associated with breast cancer risk. The absolute number of cases observed over 3 years were 30 among women in the lowest 25% of follicular total estradiol levels and 50 among women in the highest 25%. Conclusions: Levels of circulating estrogens and androgens may be important in the etiology of premenopausal breast cancer.

Background: Levels of endogenous hormones have been associated with the risk of breast cancer among postmenopausal women. Little research, however, has investigated the association between hormone levels and tumor receptor status or invasive versus in situ tumor status. Nor has the relation between breast cancer risk and postmenopausal progesterone levels been investigated. We prospectively investigated these relations in a case-control study nested within the Nurses' Health Study. Methods: Blood samples were prospectively collected during 1989 and 1990. Among eligible postmenopausal women, 322 cases of breast cancer (264 invasive, 41 in situ, 153 estrogen receptor [ER]-positive and progesterone receptor [PR]-positive [E[R.sup.+]/P[R.sup.+]], and 39 ER-negative and PR-negative [E[R.sup.-]/P[R.sup.-]] disease) were reported through June 30, 1998. For each case subject, two control subjects (n = 643) were matched on age and blood collection (by month and time of day). Endogenous hormone levels were measured in blood plasma. We used conditional and unconditional logistic regression analyses to assess associations and to control for established breast cancer risk factors. Results: We observed a statistically significant direct association between breast cancer risk and the level of both estrogens and androgens, but we did not find any (by year) statistically significant associations between this risk and the level of progesterone or sex hormone binding globulin. When we restricted the analysis to case subjects with E[R.sup.+]/P[R.sup.+] tumors and compared the highest with the lowest fourths of plasma hormone concentration, we observed an increased risk of breast cancer associated with estradiol (relative risk [RR] = 3.3, 95% confidence interval [CI] = 2.0 to 5.4), testosterone (RR = 2.0, 95% CI = 1.2 to 3.4), androstenedione (RR = 2.5, 95% CI = 1.4 to 4.3), and dehydroepiandrosterone sulfate (RR = 2.3, 95% CI = 1.3 to 4.1). In addition, all hormones tended to be associated most strongly with in situ disease. Conclusion: Circulating levels of sex steroid hormones may be most strongly associated with risk of E[R.sup.+]/ P[R.sup.+] breast tumors.

ObjectivesPhysical inactivity and sedentary behaviour are associated with higher breast cancer risk in observational studies, but ascribing causality is difficult. Mendelian randomisation (MR) assesses causality by simulating randomised trial groups using genotype. We assessed whether lifelong physical activity or sedentary time, assessed using genotype, may be causally associated with breast cancer risk overall, pre/post-menopause, and by case-groups defined by tumour characteristics.MethodsWe performed two-sample inverse-variance-weighted MR using individual-level Breast Cancer Association Consortium case-control data from 130 957 European-ancestry women (69 838 invasive cases), and published UK Biobank data (n=91 105–377 234). Genetic instruments were single nucleotide polymorphisms (SNPs) associated in UK Biobank with wrist-worn accelerometer-measured overall physical activity (nsnps=5) or sedentary time (nsnps=6), or accelerometer-measured (nsnps=1) or self-reported (nsnps=5) vigorous physical activity.ResultsGreater genetically-predicted overall activity was associated with lower breast cancer overall risk (OR=0.59; 95% confidence interval (CI) 0.42 to 0.83 per-standard deviation (SD;~8 milligravities acceleration)) and for most case-groups. Genetically-predicted vigorous activity was associated with lower risk of pre/perimenopausal breast cancer (OR=0.62; 95% CI 0.45 to 0.87,≥3 vs. 0 self-reported days/week), with consistent estimates for most case-groups. Greater genetically-predicted sedentary time was associated with higher hormone-receptor-negative tumour risk (OR=1.77; 95% CI 1.07 to 2.92 per-SD (~7% time spent sedentary)), with elevated estimates for most case-groups. Results were robust to sensitivity analyses examining pleiotropy (including weighted-median-MR, MR-Egger).ConclusionOur study provides strong evidence that greater overall physical activity, greater vigorous activity, and lower sedentary time are likely to reduce breast cancer risk. More widespread adoption of active lifestyles may reduce the burden from the most common cancer in women.

Common single-nucleotide polymorphisms (SNPs) are predicted to collectively explain 40–50% of phenotypic variation in human height, but identifying the specific variants and associated regions requires huge sample sizes1. Here, using data from a genome-wide association study of 5.4 million individuals of diverse ancestries, we show that 12,111 independent SNPs that are significantly associated with height account for nearly all of the common SNP-based heritability. These SNPs are clustered within 7,209 non-overlapping genomic segments with a mean size of around 90 kb, covering about 21% of the genome. The density of independent associations varies across the genome and the regions of increased density are enriched for biologically relevant genes. In out-of-sample estimation and prediction, the 12,111 SNPs (or all SNPs in the HapMap 3 panel2) account for 40% (45%) of phenotypic variance in populations of European ancestry but only around 10–20% (14–24%) in populations of other ancestries. Effect sizes, associated regions and gene prioritization are similar across ancestries, indicating that reduced prediction accuracy is likely to be explained by linkage disequilibrium and differences in allele frequency within associated regions. Finally, we show that the relevant biological pathways are detectable with smaller sample sizes than are needed to implicate causal genes and variants. Overall, this study provides a comprehensive map of specific genomic regions that contain the vast majority of common height-associated variants. Although this map is saturated for populations of European ancestry, further research is needed to achieve equivalent saturation in other ancestries.

A lack of prospective studies has been a major barrier for assessing the role of the microbiome in human health and disease on a population-wide scale. To address this significant knowledge gap, we have launched a large-scale collection targeting fecal and oral microbiome specimens from 20,000 women within the Nurses’ Health Study II cohort (the Microbiome Among Nurses study, or Micro-N). Leveraging the rich epidemiologic data that have been repeatedly collected from this cohort since 1989; the established biorepository of archived blood, urine, buccal cell, and tumor tissue specimens; the available genetic and biomarker data; the cohort’s ongoing follow-up; and the BIOM-Mass microbiome research platform, Micro-N furnishes unparalleled resources for future prospective studies to interrogate the interplay between host, environmental factors, and the microbiome in human health. These prospectively collected materials will provide much-needed evidence to infer causality in microbiome-associated outcomes, paving the way toward development of microbiota-targeted modulators, preventives, diagnostics and therapeutics. Here, we describe a generalizable, scalable and cost-effective platform used for stool and oral microbiome specimen and metadata collection in the Micro-N study as an example of how prospective studies of the microbiome may be carried out.

A healthy lifestyle is associated with a lower premature mortality risk and with longer life expectancy. However, the metabolic pathways of a healthy lifestyle and how they relate to mortality and longevity are unclear. We aimed to identify and replicate a healthy lifestyle metabolomic signature and examine how it is related to total and cause-specific mortality risk and longevity.

IMPORTANCE: Ovarian cancer is a highly fatal malignant neoplasm with few modifiable risk factors. Case-control studies have reported a modest reduced risk of ovarian cancer among women who frequently use aspirin or regularly use low-dose aspirin. OBJECTIVE: To evaluate whether regular aspirin or nonaspirin nonsteroidal anti-inflammatory drug (NSAID) use and patterns of use are associated with lower ovarian cancer risk. DESIGN, SETTING, AND PARTICIPANTS: This cohort study analyzed NSAID use and ovarian cancer diagnosis data from 2 prospective cohorts, 93 664 women in the Nurses’ Health Study (NHS), who were followed up from 1980 to 2014, and 111 834 in the Nurses’ Health Study II (NHSII), who were followed up from 1989 to 2015. Follow-up was completed on June 30, 2014, for the NHS and June 30, 2015, for NHSII. Data were analyzed from June 13, 2016, to September 18, 2017. EXPOSURES: For each analgesic type (aspirin, low-dose aspirin, nonaspirin NSAIDs, and acetaminophen), timing, duration, frequency, and number of tablets used were evaluated; exposure information was updated every 2 to 4 years. MAIN OUTCOMES AND MEASURES: Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs for associations of aspirin, nonaspirin NSAIDs, and acetaminophen with risk of epithelial ovarian cancer. All statistical tests were 2-sided, with a significance level of .05. RESULTS: In the NHS, the mean (SD) age at baseline (1980) was 45.9 (7.2) years, and 93% of participants identified as non-Hispanic white. In the NHSII, the mean age at baseline (1989) was 34.2 (4.7) years, and 92% identified as non-Hispanic white. Among the 205 498 women in both cohorts, there were 1054 cases of incident epithelial ovarian cancer. Significant associations between aspirin and ovarian cancer risk were not observed when current vs nonuse of any aspirin was evaluated regardless of dose (HR, 0.99; 95% CI, 0.83-1.19). However, when low-dose (≤100-mg) and standard-dose (325-mg) aspirin were evaluated separately, an inverse association for low-dose aspirin (HR, 0.77; 95% CI, 0.61-0.96), but no association for standard-dose aspirin (HR, 1.17; 95% CI, 0.92-1.49) was observed. Current use of nonaspirin NSAIDs was positively associated with risk of ovarian cancer compared with nonuse (HR, 1.19; 95% CI, 1.00-1.41), and significant positive trends for duration of use (P = .02 for trend) and cumulative average tablets per week (P = .03 for trend) were observed. There were no clear associations for the use of acetaminophen. CONCLUSIONS AND RELEVANCE: These results appear to be consistent with case-control studies that show a reduced risk of ovarian cancer among regular users of low-dose aspirin. An increased risk of ovarian cancer with long-term high-quantity use of other analgesics, particularly nonaspirin NSAIDs, was observed, although this finding requires confirmation.

Most common breast cancer susceptibility variants have been identified through genome-wide association studies (GWAS) of predominantly estrogen receptor (ER)-positive disease. We conducted a GWAS using 21,468 ER-negative cases and 100,594 controls combined with 18,908 BRCA1 mutation carriers (9,414 with breast cancer), all of European origin. We identified independent associations at P < 5 × 10−8with ten variants at nine new loci. At P < 0.05, we replicated associations with 10 of 11 variants previously reported in ER-negative disease or BRCA1 mutation carrier GWAS and observed consistent associations with ER-negative disease for 105 susceptibility variants identified by other studies. These 125 variants explain approximately 16% of the familial risk of this breast cancer subtype. There was high genetic correlation (0.72) between risk of ER-negative breast cancer and breast cancer risk for BRCA1 mutation carriers. These findings may lead to improved risk prediction and inform further fine-mapping and functional work to better understand the biological basis of ER-negative breast cancer.

Age-related macular degeneration (AMD) is a leading cause of blindness in older adults. Investigating shared genetic components between metabolites and AMD can enhance our understanding of its pathogenesis. We conduct metabolite genome-wide association studies (mGWASs) using multi-ethnic genetic and metabolomic data from up to 28,000 participants. With bidirectional Mendelian randomization analysis involving 16,144 advanced AMD cases and 17,832 controls, we identify 108 putatively causal relationships between plasma metabolites and advanced AMD. These metabolites are enriched in glycerophospholipid metabolism, lysophospholipid, triradylcglycerol, and long chain polyunsaturated fatty acid pathways. Bayesian genetic colocalization analysis and a customized metabolome-wide association approach prioritize putative causal AMD-associated metabolites. We find limited evidence linking urine metabolites to AMD risk. Our study emphasizes the contribution of plasma metabolites, particularly lipid-related pathways and genes, to AMD risk and uncovers numerous putative causal associations between metabolites and AMD risk.

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Background:A healthy lifestyle is associated with a lower risk of premature death. Metabolic pathways of a healthy lifestyle and their association with mortality remain to be understood. This study aimed to identify the metabolomic profile of a healthy lifestyle score and examine its prospective association with all-cause and cause-specific mortality, including death from cardiovascular disease (CVD) and cancer.Methods:The population included 12,146 participants from the Nurses’ Health Study (NHS), NHS II and Health Professionals Follow-Up Study (HPFS)(83% women, 97% white, aged 55±9y). Plasma metabolites were profiled using high-throughput liquid chromatography mass-spectrometry at baseline (NHS:1989-1990; NHSII:1996-1999; HPFS:1993-1995). The healthy lifestyle score was computed by summing the total number of healthy lifestyle factors participants adhered to from validated questionnaires at baseline: healthy diet (Alternative Healthy Eating Index, upper 40%), moderate alcohol intake (women: 5-15 g/d; men: 5-30 g/d), moderate-to-vigorous physical activity (≥30min/d), never smoking and normal BMI (18.5-24.9kg/m2). Deaths were ascertained with death certificates and medical records. The metabolite profile was identified using elastic net regressions with train test validation split (70-30%). Metabolic pathways were determined using Metabolite Set Enrichment Analysis (MSEA). Multivariable-adjusted Cox proportional hazards regressions were used to estimate hazard ratios and 95% confidence intervals (HR[CI]) per unit of score of the healthy lifestyle metabolite profile with mortality risk.Results:The identified profile included 88 metabolites and correlated with the healthy lifestyle score (Pearson r=0.43-0.44; p<0.001). Triglyceride and diglyceride metabolite sets were inversely associated with the healthy lifestyle score, whereas cholesteryl ester and phosphatidylcholine plasmalogen sets were directly associated (p<0.001). Among individual lifestyle factors, the profile was most strongly correlated with normal BMI (rpb=0.43; p<0.001). Over 32y of follow-up, there were 3,851 deaths, including 749 deaths from CVD and 994 from cancer. Participants with a higher healthy lifestyle metabolite profile score had lower risk of all-cause (HR=0.79[0.73, 0.85]) and CVD mortality (HR=0.77[0.58, 0.95]), but not cancer (HR=0.91[0.77, 1.05]). Significant associations persisted after further adjustment for the healthy lifestyle score.Conclusions:In US adults, we identified a metabolite profile related to a healthy lifestyle largely reflecting lipid metabolism pathways. A higher metabolite score was associated with lower subsequent all-cause mortality risk, specifically from CVD. Findings provide novel insights into potential metabolic pathways underlying the association between a healthy lifestyle and lower premature mortality.

Previous literature on dairy products and risk of breast cancer is inconsistent, and the relationship may depend on the life-period of dietary assessment.

Supplemental Digital Content is available in the text.

Supplemental Digital Content is available in the text.

Breast cancer risk is influenced by rare coding variants in susceptibility genes, such as BRCA1, and many common, mostly non-coding variants. However, much of the genetic contribution to breast cancer risk remains unknown. Here we report the results of a genome-wide association study of breast cancer in 122,977 cases and 105,974 controls of European ancestry and 14,068 cases and 13,104 controls of East Asian ancestry. We identified 65 new loci that are associated with overall breast cancer risk at P < 5 × 10−8. The majority of credible risk single-nucleotide polymorphisms in these loci fall in distal regulatory elements, and by integrating in silico data to predict target genes in breast cells at each locus, we demonstrate a strong overlap between candidate target genes and somatic driver genes in breast tumours. We also find that heritability of breast cancer due to all single-nucleotide polymorphisms in regulatory features was 2–5-fold enriched relative to the genome-wide average, with strong enrichment for particular transcription factor binding sites. These results provide further insight into genetic susceptibility to breast cancer and will improve the use of genetic risk scores for individualized screening and prevention.

Our current knowledge of modifiable risk factors to prevent myocardial infarction (MI) in young and middle-aged women is limited, and the impact of diet is largely unknown. Dietary flavonoids exert potential beneficial effects on endothelial function in short-term trials; however, the relationship between habitual intake and risk of MI in women is unknown.

There is a complex relationship between physical activity and estrogen metabolism in premenopausal women. Changes in both levels of physical activity and endogenous estrogen appear to play a role in several disease processes. It is unclear whether there is a relationship between physical activity and estrogen and its metabolites. Only 3 small cross-sectional studies have examined this relationship; 2 reported a positive relationship between physical activity and the metabolites 2-hydroxyestrone and 16-hydroxyestrone, but the third did not. Information on the effects of physical activity on estrogen metabolites other than 2-hydroxyestone and 16-hydroxyestrone is limited.

Background:Being physically active has been associated with lower risks of cardiometabolic diseases. However, the biological mechanisms underlying these associations remain unclear, and can be investigated using a metabolomics approach.Objective:To identify plasma metabolites associated with habitual physical activity in a U.S. population.Methods:Our study population included 4119 participants in the Nurses’ Health Study (NHS), NHS II, and Health Professionals Follow-up Study (HPFS). Physical activity was assessed periodically by self-reported questionnaire starting from 1984 in NHS, 1989 in NHSII, and 1986 in HPFS. We used physical activity measured closest before blood collection as exposure. Metabolic profiling was conducted by liquid chromatography-mass spectrometry (LC-MS). Our study included 287 known metabolites, with 64% of them classified as lipids (58 triglycerides [TAGs], 13 diglycerides [DAGs], 13 cholesteryl esters [CEs], 6 lysophosphatidylethanolamines [LPEs], 37 phosphocholines [PCs], 10 lysophosphatidylcholines [LPCs], 24 phosphatidylethanolamines [PEs], and 25 carnitines). We examined associations of physical activity with plasma metabolites using linear regression, and corrected for multiple testing using tail probability of the proportion of false positives (TPPFP) and accounting for correlated tests using bootstrapping.Results:Using linear model adjusting for age, case-control status, labcode, smoking status, fasting status, alcohol intake, and diet quality, physical activity was significantly associated with 27 metabolites after correcting for multiple testing (TPPFP <0.05). Among the 27 identified metabolites, four CEs, eight PCs, and three LPCs were positively associated with physical activity, and five TAGs and four DAGs were inversely associated. After additionally adjusting for body mass index (BMI), the associations of physical activity with the majority of identified metabolites were attenuated; physical activity remained positively associated with three CEs (C18:2, C16:0, and C18:1), three PCs (C36:4 PC-A, C36:0 PC, C34:3 PC plasmalogen), and one LPC (C18:2). Enrichment analysis showed that physical activity was significantly positively associated with the CE category (P value for enrichment=0.048).Conclusions:We identified seven metabolites that were significantly associated with physical activity after adjusting for BMI, which may help identify biomarkers of physical activity and provide insight into biological mechanisms underlying the beneficial effect of being physically active on cardiometabolic health.

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 &lt;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.

Objective To investigate the association between lifetime breast feeding, exclusive breast feeding, postpartum amenorrhea, and incidence of endometriosis among parous women.Design Prospective cohort study.Setting Nurses’ Health Study II, 1989-2011.Participants 72 394women who reported having one or more pregnancies that lasted at least six months, 3296 of whom had laparoscopically confirmed endometriosis. For each pregnancy, women reported duration of total breast feeding, exclusive breast feeding, and postpartum amenorrhea. Main outcome measures Incident self reported laparoscopically confirmed endometriosis (96% concordance with medical record) in parous women. Multivariable Cox proportional hazard models were used to calculate hazard ratios and 95% confidence intervals for diagnosis of endometriosis.Results Duration of total and exclusive breast feeding was significantly associated with decreased risk of endometriosis. Among women who reported a lifetime total length of breast feeding of less than one month, there were 453 endometriosis cases/100 000 person years compared with 184 cases/100 000 person years in women who reported a lifetime total of ≥36 months of breast feeding. For every additional three months of total breast feeding per pregnancy, women experienced an 8% lower risk of endometriosis (hazard ratio 0.92, 95% confidence interval 0.90 to 0.94; P<0.001 for trend) and a 14% lower risk for every additional three months of exclusive breast feeding per pregnancy (0.86, 0.81 to 0.90; P<0.001 for trend). Women who breastfed for ≥36 months in total across their reproductive lifetime had a 40% reduced risk of endometriosis compared with women who never breast fed (0.60, 0.50 to 0.72). The protective association with breast feeding was strongest among women who gave birth within the past five years (P=0.04 for interaction). The association with total breast feeding and exclusive breast feeding on endometriosis was partially influenced by postpartum amenorrhea (% mediated was 34% (95% confidence interval 15% to 59%) for total breast feeding and 57% (27% to 82%) for exclusive breast feeding).Conclusion Among women who experienced at least one pregnancy that lasted at least six months, breast feeding was inversely associated with risk of incident endometriosis. This association was partially, but not fully, influenced by postpartum amenorrhea, suggesting that breast feeding could influence the risk of endometriosis both through amenorrhea and other mechanisms. Given the chronic and incurable nature of endometriosis, breast feeding should be further investigated as an important modifiable behavior to mitigate risk for pregnant women.

Objective To evaluate the association between fruit and vegetable intake during adolescence and early adulthood and risk of breast cancer.Design Prospective cohort study.Setting Health professionals in the United States.Participants 90 476 premenopausal women aged 27-44 from the Nurses’ Health Study II who completed a questionnaire on diet in 1991 as well as 44 223 of those women who completed a questionnaire about their diet during adolescence in 1998.Main outcome measure Incident cases of invasive breast cancer, identified through self report and confirmed by pathology report.Results There were 3235 cases of invasive breast cancer during follow-up to 2013. Of these, 1347 cases were among women who completed a questionnaire about their diet during adolescence (ages 13-18). Total fruit consumption during adolescence was associated with a lower risk of breast cancer. The hazard ratio was 0.75 (95% confidence interval 0.62 to 0.90; P=0.01 for trend) for the highest (median intake 2.9 servings/day) versus the lowest (median intake 0.5 serving/day) fifth of intake. The association for fruit intake during adolescence was independent of adult fruit intake. There was no association between risk and total fruit intake in early adulthood and total vegetable intake in either adolescence or early adulthood. Higher early adulthood intake of fruits and vegetables rich in α carotene was associated with lower risk of premenopausal breast cancer. The hazard ratio was 0.82 (0.70 to 0.96) for the highest fifth (median intake 0.5 serving/day) versus the lowest fifth (median intake 0.03 serving/day) intake. The association with adolescent fruit intake was stronger for both estrogen and progesterone receptor negative cancers than estrogen and progesterone receptor positive cancers (P=0.02 for heterogeneity). For individual fruits and vegetables, greater consumption of apple, banana, and grapes during adolescence and oranges and kale during early adulthood was significantly associated with a reduced risk of breast cancer. Fruit juice intake in adolescence or early adulthood was not associated with risk.Conclusion There is an association between higher fruit intake and lower risk of breast cancer. Food choices during adolescence might be particularly important.

Objective To evaluate the association between migraine and incident cardiovascular disease and cardiovascular mortality in women.Design Prospective cohort study among Nurses’ Health Study II participants, with follow-up from 1989 and through June 2011.Setting Cohort of female nurses in United States.Participants 115 541 women aged 25-42 years at baseline and free of angina and cardiovascular disease. Cumulative follow-up rates were more than 90%.Main outcome measures The primary outcome of the study was major cardiovascular disease, a combined endpoint of myocardial infarction, stroke, or fatal cardiovascular disease. Secondary outcome measures included individual endpoints of myocardial infarction, stroke, angina/coronary revascularization procedures, and cardiovascular mortality.Results 17 531 (15.2%) women reported a physician’s diagnosis of migraine. Over 20 years of follow-up, 1329 major cardiovascular disease events occurred and 223 women died from cardiovascular disease. After adjustment for potential confounding factors, migraine was associated with an increased risk for major cardiovascular disease (hazard ratio 1.50, 95% confidence interval 1.33 to 1.69), myocardial infarction (1.39, 1.18 to 1.64), stroke (1.62, 1.37 to 1.92), and angina/coronary revascularization procedures (1.73, 1.29 to 2.32), compared with women without migraine. Furthermore, migraine was associated with a significantly increased risk for cardiovascular disease mortality (hazard ratio 1.37, 1.02 to 1.83). Associations were similar across subgroups of women, including by age (<50/≥50), smoking status (current/past/never), hypertension (yes/no), postmenopausal hormone therapy (current/not current), and oral contraceptive use (current/not current).Conclusions Results of this large, prospective cohort study in women with more than 20 years of follow-up indicate a consistent link between migraine and cardiovascular disease events, including cardiovascular mortality. Women with migraine should be evaluated for their vascular risk. Future targeted research is warranted to identify preventive strategies to reduce the risk of future cardiovascular disease among patients with migraine.

Several prospective studies have found that weight gain starting in the early adult years is associated with an increased risk of postmenopausal breast cancer. Endogenous hormones are a primary factor in breast cancer, and adiposity can alter circulating hormone levels, especially in postmenopausal women. This prospective cohort study, based on data from the Nurses’ Health Study, followed 87,143 postmenopausal women 30 to 55 years of age for up to 26 years (from 1976–2002) to discern the influence, if any, of weight change since age 18. Weight change since menopause was estimated in 49,514 women who were followed for as long as 24 years.

ObjectiveTo investigate the association between dietary protein sources in early adulthood and risk of breast cancer.DesignProspective cohort study.SettingHealth professionals in the United States.Participants88 803 premenopausal women from the Nurses’ Health Study II who completed a questionnaire on diet in 1991.Main outcome measureIncident cases of invasive breast carcinoma, identified through self report and confirmed by pathology report.ResultsWe documented 2830 cases of breast cancer during 20 years of follow-up. Higher intake of total red meat was associated with an increased risk of breast cancer overall (relative risk 1.22, 95% confidence interval 1.06 to 1.40; Ptrend=0.01, for highest fifth vlowest fifth of intake). However, higher intakes of poultry, fish, eggs, legumes, and nuts were not related to breast cancer overall. When the association was evaluated by menopausal status, higher intake of poultry was associated with a lower risk of breast cancer in postmenopausal women (0.73, 0.58 to 0.91; Ptrend=0.02, for highest fifth vlowest fifth of intake) but not in premenopausal women (0.93, 0.78 to 1.11; Ptrend=0.60, for highest fifth vlowest fifth of intake). In estimating the effects of exchanging different protein sources, substituting one serving/day of legumes for one serving/day of red meat was associated with a 15% lower risk of breast cancer among all women (0.85, 0.73 to 0.98) and a 19% lower risk among premenopausal women (0.81, 0.66 to 0.99). Also, substituting one serving/day of poultry for one serving/day of red meat was associated with a 17% lower risk of breast cancer overall (0.83, 0.72 to 0.96) and a 24% lower risk of postmenopausal breast cancer (0.76, 0.59 to 0.99). Furthermore, substituting one serving/day of combined legumes, nuts, poultry, and fish for one serving/day of red meat was associated with a 14% lower risk of breast cancer overall (0.86, 0.78 to 0.94) and premenopausal breast cancer (0.86, 0.76 to 0.98).ConclusionHigher red meat intake in early adulthood may be a risk factor for breast cancer, and replacing red meat with a combination of legumes, poultry, nuts and fish may reduce the risk of breast cancer.