The human metabolome reflects complex metabolic states affected by genetic and environmental factors. However, metabolites associated with type 2 diabetes (T2D) risk and their determinants remain insufficiently characterized. Here we integrated blood metabolomic, genomic and lifestyle data from up to 23,634 initially T2D-free participants from ten cohorts. Of 469 metabolites examined, 235 were associated with incident T2D during up to 26 years of follow-up, including 67 associations not previously reported across bile acid, lipid, carnitine, urea cycle and arginine/proline, glycine and histidine pathways. Further genetic analyses linked these metabolites to signaling pathways and clinical traits central to T2D pathophysiology, including insulin resistance, glucose/insulin response, ectopic fat deposition, energy/lipid regulation and liver function. Lifestyle factors-particularly physical activity, obesity and diet-explained greater variations in T2D-associated versus non-associated metabolites, with specific metabolites revealed as potential mediators. Finally, a 44-metabolite signature improved T2D risk prediction beyond conventional factors. These findings provide a foundation for understanding T2D mechanisms and may inform precision prevention targeting specific metabolic pathways.

Importance:Weight gain is common during menopause, and healthy dietary patterns are key to its management. However, effectiveness of different diets for weight management during this period remains unclear. Objective:To examine and compare associations of multiple dietary patterns with weight gain and obesity risk in the years surrounding menopause. Design, Setting, and Participants:This prospective, population-based cohort study included women observed over a 12-year period surrounding menopause in the Nurses' Health Study II (1989-2019). Data analysis was performed between November 2024 and May 2025. Exposures:Diet was assessed every 4 years using validated food frequency questionnaires. Dietary scores included the plant-based diet index (PDI), healthy PDI, unhealthy PDI, Mediterranean diet, Dietary Approaches to Stop Hypertension, Planetary Health Diet Index (PHDI), low-carbohydrate diet (LCD), healthy LCD, unhealthy LCD, empirical dietary inflammatory pattern, empirical dietary index for hyperinsulinemia (EDIH), and ultraprocessed food intake. Main Outcomes and Measures:The outcomes were annual changes in self-reported body weight (kilograms per year) and incident obesity. Generalized estimating equations were used to estimate annual weight change across dietary patterns. Cox proportional hazards models were used to estimate risk of obesity across dietary patterns. Results:Among 38 283 women (mean [SD] age, 45.6 [3.0] years), the mean (SD) weight gain was 0.80 (1.00) kg per year. During 340 122 person-years of follow-up, 5214 women developed obesity. After adjusting for age, race and ethnicity, marital status, income, postmenopausal hormone therapy use, parity, smoking, alcohol, energy intake, physical activity, and baseline body mass index, the reverse EDIH (quintile 5 vs 1) was associated with the largest reduction in weight gain (mean, -0.28 kg/y; 95% CI, -0.30 to -0.26 kg/y). For incident obesity, the lowest risk was observed for the PHDI (hazard ratio, 0.46; 95% CI, 0.42 to 0.51) and reverse EDIH (hazard ratio, 0.51; 95% CI, 0.46 to 0.56). EDIH showed the largest positive correlations with red or processed meats, sodium, and French fries. PHDI showed the largest positive correlations with nuts, unsaturated fats, whole grain carbohydrates, and vegetable protein. Conclusions and Relevance:In this prospective cohort study of women during menopause, adopting low-insulinemic and planetary health diets, low in red and processed meats, sodium, potatoes, and French fries and rich in nuts, legumes, fruits, vegetables, and whole grains, was associated with optimized weight management.

CONTEXT:Prior reports of plasma estradiol concentrations and their reference ranges in postmenopausal women identified marked variation, in part due to assay method and body mass index (BMI). OBJECTIVE:To develop an international reference range for plasma estradiol in postmenopausal women, to support accurate assessment of concentrations during systemic and local (e.g., vaginal) estradiol therapy, and to improve risk prediction for diseases, including osteoporosis, breast and endometrial cancers. METHODOLOGY:Estradiol concentrations were measured using primarily liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays in five international cohorts of community-dwelling, postmenopausal women of primarily European ancestry aged 38-100 years who were not using exogenous estrogens (n=7206). Measurements were harmonized to the Centers for Disease Control and Prevention (CDC) reference measurement procedure (RMP) by re-assaying a subset of samples for each cohort and generating recalibration equations. Reference intervals were determined for all women, non-obese women, and specific BMI categories. RESULTS:Estradiol concentrations from separate LC-MS/MS assays correlated closely with the CDC RMP, and harmonization minimized inter-assay variability. Estradiol concentrations correlated with BMI but not with chronological age. The reference range (2.5th-97.5th percentile) was 1.1-18.2 pg/mL (4.0 - 66.8 pmol/L) with median of 4.9 pg/mL (18.0 pmol/L) for all postmenopausal women and 1.1-12.5 pg/mL (4.0 - 45.9 pmol/L) with median of 4.1 pg/mL (15.1 pmol/L) for non-obese women (BMI<30). Reference ranges increased progressively with higher BMI categories. CONCLUSION:Cross-calibration of estradiol measurements with the CDC RP enabled the development of harmonized plasma estradiol reference ranges for postmenopausal women who were not using exogenous estrogens, suitable for future studies to establish clinical utility. Increasing obesity in postmenopausal women was associated with increasing estradiol concentration and BMI category-specific reference ranges.

BACKGROUND:Previous cohort studies of physical activity and cognitive health have often been limited by small sample sizes, short follow-up durations, absence of long-term assessments of physical activity, and potential reverse causation. We aimed to prospectively examine the associations between long-term physical activity and multiple cognitive outcomes. METHODS:In this study, we used data from two ongoing US prospective cohorts: the Nurses' Health Study (established in 1976, comprising 121 700 female registered nurses aged 30-55 years at enrolment) and the Health Professionals Follow-Up Study (HPFS; established in 1986, comprising 51 492 male health professionals aged 40-75 years at enrolment). Discretionary physical activity was assessed approximately every 2-4 years using self-report questionnaires, beginning in 1986 for both cohorts. Total physical activity, walking, and vigorous aerobic exercise were each expressed as the summed metabolic equivalent of task hours per week. We ascertained incident dementia cases (a composite endpoint of self-reported physician-diagnosed dementia and deaths due to dementia) in eligible Nurses' Health Study participants (1990-2023) and HPFS participants (1990-2023); deaths due to dementia were confirmed using medical records, death certificates, and autopsy reports. Objective cognitive function was assessed in Nurses' Health Study participants only (1995-2008) using the Telephone Interview for Cognitive Status (TICS). Subjective cognitive decline was self-reported by Nurses' Health Study participants (followed up in 2012 and 2014) and HPFS participants (followed up in 2008, 2012, 2016, 2018, and 2020) via questionnaires with binary questions that assessed subjective cognitive concerns across multiple domains. Participants were excluded from the analysis if they had dementia, stroke, cancer, were missing total physical activity or walking data, or reported difficulties with walking at baseline. Outcomes were analysed using multivariable-adjusted regression models. We used a 4-year lag approach in our main analyses to minimise the potential for reverse causation. FINDINGS:Our final samples comprised 63 596 Nurses' Health Study participants and 43 440 HPFS participants for the dementia endpoints, 13 647 Nurses' Health Study participants for assessing objective cognitive function, and 29 801 Nurses' Health Study participants and 17 162 HPFS participants for assessing subjective cognitive decline. Compared with participants in the lowest quartile for total physical activity, those in the highest quartile had a lower risk of dementia (hazard ratio [HR] 0·72, 95% CI 0·68-0·76; p<0·0001 for trend) and subjective cognitive decline (relative risk [RR] 0·77, 95% CI 0·73-0·80; p<0·0001 for trend). Being in the highest versus the lowest tertile for walking or vigorous aerobic exercise was also associated with lower risk for dementia (HR 0·76, 95% CI 0·72-0·80 for walking and 0·89, 0·85-0·93 for vigorous aerobic exercise; p<0·0001 for trend for both activities) and subjective cognitive decline (RR 0·82, 95% CI 0·79-0·86 for walking and 0·89, 0·86-0·93 for vigorous aerobic exercise; p<0·0001 for trend for both activities). Additionally, being in the highest quartile of total physical activity versus the lowest quartile was associated with fewer years of age-related cognitive differences in global cognition (mean difference -1·15, 95% CI -1·69 to -0·60; p<0·0001 for trend), verbal memory (-1·27, -1·86 to -0·68; p<0·0001 for trend), and TICS score (-0·79, -1·36 to -0·23; p=0·016 for trend). Similar decreases were observed for vigorous aerobic exercise but not for walking. INTERPRETATION:Higher levels of physical activity were associated with a lower risk of dementia and better cognitive performance. These findings support physical activity as a potential strategy to promote long-term cognitive health. FUNDING:US National Institutes of Health.

Background Low-carbohydrate diet (LCD) and low-fat diet (LFD) patterns are practiced by many in the United States, although their health effects, as well as the role of diet quality in the effects, are not fully understood. Objectives This study aimed to prospectively examine the associations of these diets, which emphasize different quantities and qualities of macronutrients, as well as their objective metabolomic indices, with coronary heart disease (CHD) risk in U.S. individuals. Methods We followed 42,720 men in the Health Professionals Follow-Up Study (HPFS) (1986-2016), 64,164 women in the Nurses’ Health Study (NHS) (1986-2018), and 91,589 women in NHSII (1991-2019) for CHD incidence. Five LCD and 5 LFD indices were derived based on food frequency questionnaire (FFQ) assessments, each emphasizing different sources and qualities of macronutrients (animal products vs plant-based foods, whole grains vs refined carbohydrates, etc). Multimetabolite scores of LCD and LFD indices assessed using FFQ assessments were developed through elastic net regressions among 1,146 healthy participants in the lifestyle validation studies (LVS), substudies embedded in the NHS/NHSII/HPFS. Results During 5,248,916 person-years of follow-up, we documented 20,033 CHD cases. When comparing individuals with the highest LCD scores (emphasizing lower carbohydrate contents) and those with the lowest, the pooled multivariable-adjusted hazard ratios (95% CIs) for CHD were 1.05 (1.01-1.10) for overall LCD, 1.07 (1.02-1.12) for animal LCD, 0.94 (0.90-0.99) for vegetable LCD, 1.14 (1.09-1.20) for unhealthy LCD, and 0.85 (0.82-0.89) for healthy LCD. These estimates were 0.93 (0.89-0.98) for overall LFD, 0.94 (0.90-0.98) for animal LFD, 0.87 (0.83-0.91) for vegetable LFD, 1.12 (1.07-1.17) for unhealthy LFD, and 0.87 (0.83-0.91) for healthy LFD. The healthy versions of the LCD and LFD patterns were also linked to lower triglycerides, higher high-density lipoprotein cholesterol, and lower high-sensitivity C-reactive protein levels, as well as favorable metabolomic profiles, including increased 3-indolepropionic acid and decreased valine. Unhealthy patterns showed opposite associations. Multimetabolite scores of LCD and LFD indices were developed in the LVS (Spearman r = 0.57-0.68) and replicated in NHS, NHSII, and HPFS (r = 0.21-0.38). They showed associations with CHD risk highly consistent with those based on FFQ assessments. Conclusions These findings highlight the critical role of diet quality in determining health effects of low-carbohydrate and low-fat diets on CHD risk. The healthy versions of these diets may exert their health benefits through some common pathways that together entail favorable cardiovascular risk profile and lower CHD risk.

Objective. This study aimed to characterize plasma metabolomic signatures reflecting the metabolic pathways of plant and animal protein intake, and examine their association with the risk of type 2 diabetes (T2D). Methods. In three cohorts, plasma metabolites were profiled from 11,742 participants from the Nurses’ Health Study (NHS; mean age 56.8 y), NHSII (mean age 44.6 y), and Health Professional’s Follow-Up Study (mean age 63.3 y) using liquid chromatography mass spectrometry. Protein intakes (% kcal) were derived from two repeated food frequency questionnaires closest to the blood draw. Elastic net regressions identified metabolomic signatures of plant and animal protein intake and their ratio. Metabolomic signatures were replicated in the Women’s Health Initiative (WHI; n = 2,092) cohort. Multivariable-adjusted Cox regression models evaluated associations between signatures and T2D. Results. Signatures for plant protein, animal protein, and their ratio comprised 63, 50, 40 metabolites. Seventeen metabolites overlapped between the three signatures, including creatine, C34:5 phosphatidylcholine plasmalogens, C18:0 sphingomyelin, and N-acetylornithine. Higher plant protein signature scores were associated with lower T2D risk [HR per 1SD = 0.91 (0.83, 1.00); p = 0.049], while higher animal protein signature scores were associated with higher risk [HR per 1SD = 1.13 (1.03, 1.23); p = 0.008], with consistent replication. Conclusions. Plant and animal protein intake have distinct plasma metabolomic signatures. The biological footprint of plant protein exposure is favorably associated with T2D, whereas that of animal protein is adverse. Findings from these prospective cohort studies support that increased plant protein intake may provide benefits for T2D prevention.

Metabolomic indices summarizing diet-related metabolic responses are instrumental for examining and replicating diet–disease associations. Here we aim to identify metabolomic signatures characterizing the amounts and types of dietary carbohydrate and assess their associations with type 2 diabetes (T2D) risk. Nutritional metabolomics indices were developed using data from 1,196 healthy participants in the Lifestyle Validation Study with 7-day diet records (7DDRs). Elastic net regression within cross-validation was used to derive metabolomic indices of total carbohydrates and primary food sources. Replication was conducted using feeding menu data among 153 women from the Nutrition and Physical Activity Assessment Study. Associations with incident T2D were examined using multivariable Cox regression in 11,454 participants from the Nurses’ Health Study, Nurses’ Health Study II and Health Professionals Follow-up Study. Metabolites positively associated with total carbohydrates and added sugars mainly included glycerolipids (diacylglycerols and triglycerides), whereas glycerophospholipids (phosphatidylethanolamines and phosphatidylcholines) were inversely associated. Whole grains were linked to betaine, 3-indolepropionic acid (IPA) and hippuric acid; vegetables and legumes to IPA, N-acetylornithine and pipecolic acid; and fruits to proline-betaine and IPA. Identified metabolomic signatures showed significant correlations with a 7-day diet record-assessed diet in the Lifestyle Validation Study (Pearson r 0.33–0.65). In the Nutrition and Physical Activity Assessment Study, the metabolomic index of total carbohydrates was also significantly correlated with intake (r = 0.40). Signatures for total carbohydrates, added sugars, refined grains and potatoes were associated with higher T2D risk (HR per s.d. (95

Background: Few prospective human studies have characterized interrelationships between body weight, gut microbiome, plasma metabolome, and incident type 2 diabetes (T2D). Aims: To identify microbial profiles associated with adiposity, derive its responsive metabolomic signatures, and evaluate their associations with future weight change and incident T2D. Methods: Shotgun stool metagenomes were profiled in the Men’s Lifestyle Validation Study (MLVS; n=924). Body mass index (BMI)-associated microbial species were identified after adjusting for age, total energy, physical activity, alcohol and smoking, and were synthesized into a composite microbiome score. We evaluated its association with waist-to-hip ratio (WHR) and DEXA-measured fat mass in MLVS and validated its association with BMI in female Mind–Body Study (MBS; n=807). Next, the score was examined for its association with prevalent T2D in the multiethnic Micro-Cardio consortium (n=8,117). Prospectively, we tested its predictability of 2-year BMI increase and incident T2D risk in the Micro-N (n=3,318). To further characterize the downstream metabolism of this microbial profile, we linked it to >300 LC–MS metabolites in the MLVS and derived a microbiome-informed multi-metabolite score, which was validated in the MBS. We examined the metabolomic score for incident T2D risk in a prospective cohort, the Nurses’ Health Study (NHS; n=1,057). Results: We identified 23 microbial species associated with BMI in MLVS. The 23-species composite score was correlated with higher BMI (High vs.Low: MLVS β=3.45; MBS β=4.37 both P<0.001), and also correlated with WHR (r=0.45) and fat mass (r=0.73). Additionally, higher microbiome score consistently predicted 2-year BMI increase (β=0.22, P =0.003) and predicts incident T2D in Micro-N (HR [high vs. low] = 2.19, P=0.01), as well as prevalent T2D in the Micro-Cardio (HR [per SD] =1.19, P<0.001). A 32-plasma metabolite signature was responsive to this microbial profile in MLVS (r=0.66) and validated in MBS (r=0.38), and also predicted incident T2D in NHS (RR=2.18, P<0.0001) independent of baseline BMI. Conclusions: We identified and validated a gut microbiome score predictive of adiposity across multiple cohorts, showing consistent associations with plasma metabolomic signatures and increased risk of T2D. This highlights a potential role of the gut microbiome in weight regulation and T2D development, providing new insights into microbiome-informed strategies for T2D prevention.

INTRODUCTION:Associations of adherence to and changes in Mediterranean (MedDiet) and Mediterranean-Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay (MIND) diets with cognitive outcomes are unclear. METHODS:We prospectively followed 86,740 women (Nurses' Health Study, 1980-2023) and 43,500 men (Health Professionals Follow-Up Study, 1986-2023). Diet was assessed repeatedly using food frequency questionnaires. Dementia cases were identified from self-reported physician diagnoses and death records. Cognitive function was assessed by telephone tests, and subjective cognitive decline (SCD) was self-reported. RESULTS:Participants in the highest versus lowest MedDiet and MIND categories had 21% (hazard ratio [HR] = 0.79, 95% confidence interval [CI]: 0.73-0.84) and 14% (HR = 0.86, 95% CI: 0.81-0.91) lower dementia risk, respectively. Higher adherence was associated with 0.75 to 1.59 fewer years of cognitive aging, and 40% to 42% lower risk of SCD. Similar inverse associations were observed for improved adherence over 4 or 8 years. DISCUSSION:Adherence to Mediterranean and MIND diets was associated with cognitive benefits.

Background: Mammograms contain imaging biomarkers that can predict future breast cancer risk using deep learning (DL) models. We evaluated whether adding a polygenic risk score (PRS) improves performance of the image-only DL breast cancer risk model Mirai. Methods: This nested case-control study within the Nurses' Health Study 2 included 902 women (270 cases, 632 controls) who underwent bilateral 2D digital screening mammography between 2001-2017. Risk was assessed using Mirai and, for clinical comparison, the Gail 5-year model. A PRS was calculated using 313 breast cancer-associated single-nucleotide polymorphisms. The primary outcome was incident breast cancer within five years of the index mammogram. Discrimination was evaluated using area under the receiver operating characteristic curve (AUC), with comparisons using the DeLong test. Results: Mean age was 55.5 years(SD 5.3). Among cases, median time from index mammogram to diagnosis was 2.0 years (IQR0.5-4.0). Mirai alone achieved an AUC of 0.66 (95% CI: 0.62-0.70), increasing to 0.73 (95% CI 0.67-0.78; P = 0.05) with PRS. The Gail model improved from 0.52 (95% CI: 0.47-0.57) to 0.69 (95% CI: 0.62-0.76; P < 0.001) with PRS. Mirai+PRS significantly outperformed Gail+PRS (P < 0.001). Conclusions: Integrating PRS with DL-based mammographic models modestly improves risk discrimination and may enhance personalized screening.

Background: In aging societies, improving health-related quality of life (HRQoL) is vital, as it not only predicts cardiovascular disease and mortality but also reflects overall wellbeing. Because HRQoL often declines across menopause, a pivotal stage of women’s aging, we prospectively examined and compared 11 dietary patterns with HRQoL change during the transition. Methods: We analyzed 23,129 women from the Nurses’ Health Study (NHS) and NHSII who entered menopause between the first diet and the last of HRQoL assessment (NHS: 1984–2000; NHSII: 1991–2001). HRQoL was measured with the Medical Outcomes Study 36-Item Short Form Health Survey, yielding eight domains summarized as Physical (PCS) and Mental (MCS) Component Scores. Diet was assessed with validated food-frequency questionnaires. We calculated cumulative average scores for 11 dietary pattern indices across assessments prior to outcome assessment and categorized them into quintiles. Generalized linear models with repeated measures estimated mean 4-year changes in HRQoL. Results: During the follow-up, mean (SD) PCS declined [−1.30 (7.41) points/4-years] and MCS improved [1.58 (8.26)]. Healthier dietary patterns [Plant-based Diet Index (PDI), healthy PDI (hPDI), Mediterranean Diet (MedDiet), Dietary Approaches to Stop Hypertension (DASH), Mediterranean–DASH Intervention for Neurodegenerative Delay (MIND), Alternative Healthy Eating Index(AHEI)-2010, Planetary Health Diet Index (PHDI)] were associated with less declines in PCS scores and unhealthy patterns [unhealthy PDI (uPDI), empirical dietary inflammation pattern (EDIP), empirical dietary index for hyperinsulinemia (EDIH), ultra-processed foods (UPF)] were associated with more PCS declines, with the largest magnitudes [Δ, Q5 vs. Q1 (95% CI)] observed for MIND [0.56 (0.38, 0.75)]. Healthier dietary patterns (hPDI, MedDiet, DASH, MIND, AHEI) were associated with greater MCS improvement, and unhealthy patterns (uPDI and UPF) were associated with less MCS improvement, showing the largest magnitudes for DASH [0.46 (0.27, 0.65)]. Associations were similar across eight domains. More vegetables, fruits, fish aligned with better HRQoL change; more fast/fried foods, sweetened drinks or snacks, and red and processed meat aligned with worse. Conclusions: Plant-forward, neuroprotective and blood pressure–lowering patterns, including healthy animal based and less processed foods may optimize physical and mental wellbeing across menopause.

BACKGROUND:Experimental models suggest that in utero photoperiod influences circadian regulation and systems tied to later-life anxiety, depression, and addiction. Whether in utero photoperiod is associated with mental health and substance use in adolescents and young adults remains unknown. METHODS:10,721 full term born children from the GUTS cohort contributed to these analyses. Total photoperiod was calculated by summing daily light hours across 280 gestational days using each offspring's exact birth date and state. We used multivariable adjusted generalized estimating equations, logistic regression, and linear regression to estimate odds ratios (ORs) and mean differences (MDs) for self-reported mental health and substance use outcomes across quintiles of in utero photoperiod. RESULTS:We observed no association between in utero photoperiod and mental health outcomes. Marijuana, opioids, stimulants, and alcohol use also did not differ by photoperiod. However, offspring in the top versus bottom photoperiod had lower odds of ever smoking [MV-ORQ5vsQ1, 0.89; 95% CI: 0.80,0.99; P = 0.08], smoked fewer cigarettes per day [MV-MDQ5vsQ1, -0,16; 95%CI: -0.29,-0.04; P = 0.02], and showed lower nicotine dependence [MV-MDQ5vsQ1, -0,46; 95%CI: -0.8,-0.12; P = 0.007]. No sex interactions were observed for mental health; for smoking and marijuana, males had lower odds of use. CONCLUSION:In utero photoperiod was not associated with mental health. Greater prenatal light exposure was linked to reduced smoking, but not alcohol or marijuana use, in offspring. Further research should examine cumulative prenatal and postnatal photoperiod effects on these outcomes.

This study examined the association between perceived stress and mental/physical health (SF-12) and the moderating role of positive and negative religious coping using data (n = 5,059) from three cohorts (the Hispanic Community Health Study/Study of Latinos (n = 585), Nurses’ Health Study II (n = 3,882), and The Strong Heart Study (n = 592)) which included Hispanic/Latino, non-Hispanic White, and American Indian individuals in the USA. By incorporating cohorts representing historically underserved racial and ethnic populations, this study contributes to the limited literature examining religious coping styles and stress across diverse groups. We examined the interaction between positive and negative religious coping and stress on mental/physical health, controlling for age, income, marital status, and education. Greater perceived stress was associated with poorer mental health [β = − 1.04 (− 1.37,− 0.7), p < 0.0001], but not worse physical health. Concerning moderation, positive religious coping attenuated [β = 0.23 (0.11, 0.35), p < 0.0001] and negative religious coping worsened [β = − 0.45 (− 0.88,− 0.02), p = 0.0034] the association between perceived stress and mental health in the combined analysis. Of note, patterns varied across cohorts, indicating that the role of religious coping style in shaping stress–health relationships may differ across cultural and religious contexts. Our findings highlight the importance of considering both positive and negative religious coping styles when examining psychosocial stress and mental health outcomes across diverse populations.

Importance:Evidence linking coffee and tea to cognitive health remains inconclusive, and most studies fail to differentiate caffeinated from decaffeinated coffee. Objective:To investigate associations of coffee and tea intake with dementia risk and cognitive function. Design, Setting, and Participants:Prospective cohort study that included female participants from the Nurses' Health Study (NHS; n = 86 606 with data from 1980-2023) and male participants from the Health Professionals Follow-up Study (HPFS; n = 45 215 with data from 1986-2023) who did not have cancer, Parkinson disease, or dementia at study entry (baseline) in the US. Exposures:The primary exposures were intakes of caffeinated coffee, decaffeinated coffee, and tea. Dietary intake was collected every 2 to 4 years using validated food frequency questionnaires. Main Outcomes and Measures:The primary outcome was dementia, which was identified via death records and physician diagnoses. The secondary outcomes included subjective cognitive decline assessed by a questionnaire-based score (range, 0-7; higher scores indicate greater perceived decline; cases defined as those with a score ≥3) and objective cognitive function assessed only in the NHS cohort using telephone-based neuropsychological tests such as the Telephone Interview for Cognitive Status (TICS) score (range, 0-41) and a measure of global cognition (a standardized mean z score for all 6 administered cognitive tests). Results:Among 131 821 participants (mean age at baseline, 46.2 [SD, 7.2] years in the NHS cohort and 53.8 [SD, 9.7] years in the HPFS cohort; 65.7% were female) during up to 43 years of follow-up (median, 36.8 years; IQR, 28-42 years), there were 11 033 cases of incident dementia. After adjusting for potential confounders and pooling results across cohorts, higher caffeinated coffee intake was significantly associated with lower dementia risk (141 vs 330 cases per 100 000 person-years comparing the fourth [highest] quartile of consumption with the first [lowest] quartile; hazard ratio, 0.82 [95% CI, 0.76 to 0.89]) and lower prevalence of subjective cognitive decline (7.8% vs 9.5%, respectively; prevalence ratio, 0.85 [95% CI, 0.78 to 0.93]). In the NHS cohort, higher caffeinated coffee intake was also associated with better objective cognitive performance. Compared with participants in the lowest quartile, those in the highest quartile had a higher mean TICS score (mean difference, 0.11 [95% CI, 0.01 to 0.21]) and a higher mean global cognition score (mean difference, 0.02 [95% CI, -0.01 to 0.04]); however, the association with global cognition was not statistically significant (P = .06). Higher intake of tea showed similar associations with these cognitive outcomes, whereas decaffeinated coffee intake was not associated with lower dementia risk or better cognitive performance. A dose-response analysis showed nonlinear inverse associations of caffeinated coffee and tea intake levels with dementia risk and subjective cognitive decline. The most pronounced associated differences were observed with intake of approximately 2 to 3 cups per day of caffeinated coffee or 1 to 2 cups per day of tea. Conclusions and Relevance:Greater consumption of caffeinated coffee and tea was associated with lower risk of dementia and modestly better cognitive function, with the most pronounced association at moderate intake levels.

Introduction: Pet ownership is widespread, with many owners reporting emotional benefits, but evidence on its psychological and biological effects remains mixed. Prior research has linked strong pet attachment, particularly to dogs, to lower psychosocial distress, but underlying biological mechanisms are not well understood. We examined associations of pet ownership and attachment with a metabolite-based psychosocial distress score (MDS) and broader metabolic profiles, distinguishing between dogs and cats. Methods: We analyzed data from 213 participants (131 pet owners, 82 non-owners), using the Lexington Attachment to Pets Scale and a previously developed MDS reflecting psychosocial distress. Linear regression assessed associations between pet variables and MDS or individual metabolites, adjusting for demographic, lifestyle, and health factors. Metabolite set enrichment analysis identified associated metabolite classes. Results: Pet ownership and pet attachment were not associated with MDS overall. However, stronger pet attachment was associated with lower MDS (β(95%CI)=-0.58(-1.07,-0.08), p=0.02) among dog owners but not cat owners. Across all measured metabolites, N6,N6-dimethyllysine was significantly associated with pet attachment. Several metabolite classes were associated with pet ownership and attachment, with some in opposite directions. For example, triglycerides with than three double bonds were positively associated with ownership but inversely with attachment, particularly among cat owners. Conclusion: Although pet ownership and attachment were not associated with MDS overall, stronger attachment was associated with lower MDS among dog owners but not cat owners. Pet ownership and attachment showed distinct metabolomic patterns, with differences between dog and cat owners. Further studies are needed to replicate and expand on these findings. ### Competing Interest Statement The authors have declared no competing interest. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study protocol was approved by the Institutional Review Board of Brigham and Women's Hospital and the Committee on the Use of Human Subjects in Research of Harvard T.H. Chan School of Public Health (Boston, MA, USA). Voluntary return of questionnaires indicates informed consent. The study was conducted in accordance with all relevant ethical guidelines and regulations, including the Declaration of Helsinki. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Due to participant confidentiality and privacy concerns, data cannot be shared publicly and requests to access NHS/NHSII data must be submitted in writing. According to standard controlled access procedures, applications to use NHS/NHSII resources will be reviewed by our External Collaborations Committee to verify that the proposed use maintains the protection of the privacy of participants and the confidentiality of the data. Investigators wishing to use NHS/NHSII data are asked to submit a brief description of the proposed project. Please see https://www.nurseshealthstudy.org/researchers (contact email: nhsaccess{at}channing.harvard.edu) for details. National Institutes of Health, https://ror.org/01cwqze88, R01 HD101101, U01 HL145386, U01 CA176726, U01 CA167552

BACKGROUND:In 2019, the EAT-Lancet commission defined a "planetary health diet", a combination of food groups and ranges of food intakes that would simultaneously optimize human health and environmental sustainability. We aimed to evaluate adherence to the Planetary Health Diet Index (PHDI) and breast cancer incidence. METHODS:We followed 68,254 participants in the Nurses' Health Study (NHS; 1986-2018) and 93,283 in the Nurses' Health Study II (NHSII; 1991-2019). The PHDI was calculated every 4 y using a validated, semiquantitative food frequency questionnaire. Hazard ratios (HRs) were calculated using multivariable proportional-hazards models. RESULTS:During 4,182,897 person-years of follow-up, we documented 10,378 invasive breast cancer cases. Women in the highest, compared to lowest, PHDI quintile (Q) were at lower breast cancer risk (HRQ5 vs. Q1 = 0.89; 95% CI: 0.84, 0.95; P-trend<0.01) even after adjusting for weight change. Although heterogeneity by estrogen receptor (ER) status was nonsignificant, the strongest association was observed for estrogen receptor (ER) negative tumors (HRQ5 vs. Q1 = 0.79; 95% CI: 0.66, 0.93; P-trend = 0.01). CONCLUSIONS:Adhering to a diet that supports both human and planetary health was associated with lower breast cancer risk, particularly ER-negative tumors. Strategies to reduce breast cancer incidence should emphasize the win-win opportunities for a high planetary health diet.

Abstract BACKGROUND: While over 80% of sexually active premenopausal women use oral contraception (OC), the biological mechanisms linking OC to hormone-sensitive cancers are not well understood. OC use lowers ovarian cancer risk while current use modestly increases breast cancer risk, suggesting complex underlying pathways. We sought to identify plasma metabolites associated with OC use in premenopausal women and relationships with ovarian and breast cancer. METHODS: Analysis included 2,072 premenopausal women in Nurses’ Health Study II with self-reported OC history. OC use was defined as ≥1 years of previous use, excluding current users. All metabolite values were transformed to probit scores to achieve normality. Associations of prior use ≥1 years versus never and per 5 years use with individual metabolites were evaluated through multivariable linear regression, accounting for the number of effective tests (NEF) based on the number of principal components explaining 90% of the variance. Metabolite groups were identified through metabolite set enrichment analysis (MSEA) using false discovery rate (FDR) for multiple testing. OC use models were adjusted for blood draw variables (age, time, season, fasting status), BMI smoking, diet (Alternative Healthy Eating Index score), alcohol consumption, and physical activity at the time of blood draw. Associations of metabolite groups (FDR<0.20) and metabolites (NEF<0.20) were considered nominally associated with OC use. Associations with incident breast (n=663) and ovarian cancers (n=34) diagnosed at least ≥3 years after blood draw were assessed using conditional logistic regression, using controls matched 1:1 on blood draw variables, adjusting for age, OC duration, parity, and family history of breast or ovarian cancer and using MSEA. RESULTS: Of 2,703 women, 1,681 (81.1%) reported having previously used OC for ≥1 year, with a mean duration of 4.0±3.9 years. Each additional 5 years of OC use was associated with higher C40:6 phosphatidylethanolamines (PE) levels (β=0.09; 95% CI: 0.04, 0.14), and both phosphatidylcholines and PEs were negatively associated with OC use and duration but positively for breast and ovarian cancer risk. Increasing OC duration was associated with lower tryptophan (β=-0.11; 95% CI: -0.16, -0.05) and higher 1,7-methyluric acid (β=-0.11; 95% CI: -0.16, -0.05), which were both lower among breast cancer cases and higher among ovarian cancer cases, but the overall organoheterocyclic compound group was not significantly associated with OC use. CONCLUSION: Our results suggest long-lasting alterations of systemic metabolism may in part explain associations of OC use with breast and ovarian cancers, particularly among metabolites that contribute to lipid metabolism. Analyses are ongoing and will include a deeper investigation into timing and formulation of OC use as well as cancer subtypes. Citation Format: Jennifer M. Mongiovi, Nan Lin, Oana Alina Zeleznik, Naoko Sasamoto, Britton Trabert, Julian Avila-Pacheco, Clary B. Clish, A. Heather Eliassen, Shelley TWOROGER, Kathryn L. Terry. Plasma metabolomic profiles of oral contraception use associated with breast and ovarian cancers among premenopausal women in Nurse’s Health Study II [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2317.

Background The timing of exposure to diet across the lifespan may be critical in the development of T2D. However, no previous study has deciphered the influence of dietary insulinemic and inflammatory potential on the risk of T2D across the lifespan from a life course perspective. Objective This study aimed to evaluate the associations of dietary insulinemic and inflammatory potential with the risk of T2D from a life course perspective. Design This was a prospective cohort study. Participants and setting Data from 40,135 eligible, female participants in the Nurses’ Health Study II were analyzed. Adulthood diet was assessed quadrennially since 1991 using 131-item food frequency questionnaires (FFQ), and adolescent diet was recalled in 1997 using a 124-item high-school FFQ. The main exposures were empirical dietary index for hyperinsulinemia (EDIH) and empirical dietary inflammatory pattern (EDIP) scores across different life stages (adolescence, premenopausal adulthood, postmenopausal adulthood) and changes and cumulatively over the lifetime. Main outcome measures The main outcome was incident T2D. Statistical analyses performed Cox models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI). Results Higher EDIH and EDIP scores (highest vs lowest quintiles) were associated with increased lifetime risk of T2D as a lifetime average (HR, 95%CI: 2.72, 2.38-3.11 and 2.04, 1.81-2.30), during premenopausal adulthood (3.18, 2.52-4.01 and 2.31, 1.88-2.82), and postmenopausal adulthood (2.67, 2.15-3.33 and 1.70, 1.41-2.05), but not during adolescence (1.07, 0.95-1.20 and 1.10, 0.98-1.24). The HR, 95%CI associated with higher lifetime averages for both EDIH and EDIP (vs. low lifetime averages for both, based on tertiles) was 2.64 (2.32-3.01). Individuals with high adulthood EDIH or EDIP had similar magnitudes of lifetime risk elevation, regardless of their adolescent EDIH and EDIP status. Adolescent EDIH and EDIP were associated with a slightly increased premenopausal T2D risk (1.24, 1.02-1.51, and 1.24, 1.02-1.50). In additional analyses estimating the time window during which adulthood dietary insulinemic and inflammatory potential influences T2D risk, higher adulthood EDIH or EDIP was associated with an increased risk of T2D with a very short time lag. Conclusions Over the life course in women, high dietary insulinemic and inflammatory potential in both premenopausal and postmenopausal adulthood were independently associated with a substantially increased lifetime risk of T2D. Adulthood offers the most critical time window for dietary interventions to reduce lifetime T2D risk, though adolescent diet may influence the risk of premenopausal T2D.

Introduction: Conjugated linoleic acid (CLA), a ruminant-derived fatty acid abundant in dairy and red meat, has been consumed as a dietary supplement for its purported health benefits. We aimed to prospectively investigate the association of CLA intake with coronary heart disease (CHD) risk in U.S. individuals and to explore the synergistic roles of host metabolome and gut microbiome. Methods: We followed 64,090 women from the Nurses’ Health Study (1986–2018) and 42,659 men from the Health Professionals Follow-Up Study (1986–2016) for incident CHD. Intake of CLA was assessed using 7-day diet records in the Lifestyle Validation Study (LVS) and validated food frequency questionnaires administrated quadrennially in the cohorts. Plasma metabolomic signatures responsive to CLA were derived using elastic net regression in the LVS (n=1,143). The gut microbiome was profiled in the Men’s LVS (n=307) and in a CHD case–control substudy (n=152). Results: Dietary CLA intake was associated with distinct alterations in the plasma metabolome and gut microbiome. Higher CLA intake was linked to elevated phospholipids, primarily phosphatidylethanolamine (PE 34:0) and phosphatidylcholine (PC 34:4, 36:4), and triacylglycerols with 0-2 double bonds (TAGs 49:2, 50:0, 50:1, 51:1), all positively linked to CHD risk. Conversely, CLA intake was related to lower levels of TAGs with more double bonds (54:3, 54:4). Higher CLA intake was associated with reduced Bacteroides clarus abundance (FDR = 0.03), which was inversely linked to ruminant fat–derived TAG 51:1. In the case–control substudy, higher B. clarus abundance predicted lower CHD risk ( P < 0.25). A multi-metabolite signature for cis-9, trans-11 CLA, composing 86 metabolites, showed a strong correlation with dietary intake (Spearman r = 0.73) and predicted higher fatal CHD risk (HR 1.82, 95% CI 1.11–2.99). In contrast, the metabolomic signature for trans-10, cis-12 CLA showed no significant association. In the two cohorts, higher cis-9, trans-11 CLA intake was also consistently associated with a greater risk of CHD (pooled HR for highest vs lowest quintile: 1.27, 95% CI 1.11–1.45), driven by fatal CHD (HR 1.50, 95% CI 1.24–1.81). Conclusions: Higher intake of conjugated linoleic acid, particularly cis-9, trans-11 isomer, was associated with increased risk of fatal CHD and unfavorable plasma metabolomic profiles. These associations were potentially modulated by specific gut microbial taxa, such as Bacteroides clarus .

BACKGROUND:Stomach cancer presents complex etiologic heterogeneity. Ethanol in alcoholic beverages and its metabolite acetaldehyde are carcinogens causally linked to several cancers, but their role in gastric carcinogenesis has not been established. We analyzed harmonized, individual-level prospective data to examine associations between alcohol intake and risk of stomach cancer and its subtypes. METHODS:2,009,951 participants in 20 cohorts (mean follow-up=9-29 years) within the Pooling Project of Prospective Studies of Diet and Cancer (n = 8,357 incident invasive gastric adenocarcinomas) were included. We used Cox regression to assess associations between alcohol intake and risk of stomach cancer overall and by anatomical and histological subtype and population subgroup, adjusting for confounders. RESULTS:Evidence for an association between alcohol intake and overall stomach cancer risk was weak (hazard ratio, HR, for ≥30 v 0.1-<5 g/day: 1.06 [95% confidence interval, CI, 0.96 to 1.16], P between-studies heterogeneity=0.43). Positive associations with stomach cancer risk were observed in never smokers (HR, for ≥30 v 0.1-<5 g/day: 1.20 [95% CI, 1.02 to 1.42]; P interaction=0.02) and for Asian studies (HR, 1.21 [95% CI, 1.02 to 1.42]; P interaction=0.01). Modest increased risks were observed for non-cardia cancers such as those of the fundus, body and greater curvature, but not distally located non-cardia cancers. HRs did not differ materially between diffuse- and intestinal-type cancers (P heterogeneity>0.05). CONCLUSION:There was little evidence of an overall association between alcohol intake and stomach cancer risk, although modest positive associations were observed among never smokers and in Asian cohorts.