Outcomes ascertainment and adjudication methods in the women's health initiative

– Disparities in incident stroke risk among women by race and ethnicity persist. Few studies report the distribution and association of stroke risk factors by age group among a diverse sample of women.

– Data from the Women's Health Initiative (WHI) Observational Study collected between 1993 and 2010 were used to calculate cumulative stroke incidence and incidence rates among non-Hispanic African American (NHAA), non-Hispanic white (NHW), and Hispanic white or African American (HWAA) women by age group in participants aged ≥50 years at baseline (N = 77,247). Hazard ratios (HRs) and 95% CIs for biological, behavioral, psychosocial, and socioeconomic factors overall and by race or ethnicity were estimated using sequential Cox proportional hazard regression models.

– Average follow-up time was 11.52 (SD, 3.48) years. The incident stroke rate was higher among NHAA (306 per 100,000 person-years) compared to NHW (279/100,000py) and HWAA women (147/100,000py) overall and in each age group. The disparity was largest at ages >75 years. The association between stroke risk factors (e.g., smoking, BMI, physical activity) and incident stroke varied across race and ethnicity groups. Higher social support was significantly associated with decreased stroke risk overall (HR:0.84, 95% CI, 0.76, 0.93); the degree of protection varied across race and ethnicity groups. Socioeconomic factors did not contribute additional stroke risk beyond risk conferred by traditional and psychosocial factors.

– The distribution and association of stroke risk factors differed between NHAA and NHW women. There is a clear need for stroke prevention strategies that address factors driving racial disparities in stroke risk.

Phytosterols are structurally similar to cholesterol and partially inhibit intestinal absorption of cholesterol, although their impact on coronary artery disease (CAD) risk remains to be elucidated.

This study aimed to prospectively assess the associations between total and individual phytosterol intake and CAD risk in United States health professionals.

The analysis included 213,992 participants from 3 prospective cohorts—the Nurses’ Health Study (NHS), NHSII, and Health Professionals Follow-Up Study—without cardiovascular disease or cancer at baseline. Diet was assessed using a validated food frequency questionnaire every 2–4 y since baseline. Associations between phytosterol intake and the risk of CAD, such as nonfatal myocardial infarction and fatal CAD, were evaluated using Cox proportional hazards regression models.

More than 5,517,993 person-years, 8725 cases with CAD were documented. Comparing extreme quintiles, pooled hazard ratios (95% CIs) of CAD were 0.93 (0.86, 1.01; P-trend = 0.16) for total phytosterols, 0.89 (0.82, 0.96; P-trend = 0.05) for campesterol, 0.95 (0.88, 1.02; P-trend = 0.10) for stigmasterol, and 0.92 (0.85, 1.00; P-trend = 0.09) for β-sitosterol. Nonlinear associations were observed for total phytosterols, campesterol, and β-sitosterol: the risk reduction plateaued at intakes above ∼180, 30, and 130 mg/d, respectively (P-nonlinearity < 0.001). In a subset of participants (N range between 11,983 and 22,039), phytosterol intake was inversely associated with plasma concentrations of total cholesterol, triglycerides, high-density lipoprotein cholesterol, and IL-6 and positively associated with adiponectin, whereas no significant associations were observed for low-density lipoprotein cholesterol or C-reactive protein concentrations.

Higher long-term intake of total and major subtypes of phytosterols may be associated with a modest reduction in CAD risk, displaying a nonlinear relationship that plateau at moderate intake levels. The role of phytosterols in preventing CAD warrants further investigation.

The association of total energy intake (EI) with all-cause mortality is uncertain as are the dependencies of this association on age and weight change history.

To identify an EI biomarker suitable for use in epidemiologic association studies and to study EI associations with total mortality in a Women’s Health Initiative (WHI) cohort of postmenopausal United States females (1993–present).

EI biomarkers were developed based on doubly labeled water (DLW) total energy expenditure (TEE) and weight variation during the 2-wk DLW protocol period using the energy balance method in an embedded feeding study (n = 153). This along with 2 earlier WHI nutrition biomarker studies having TEE assessments (n = 1131 total), with 14.6 y (median) follow-up, constituted a prospective cohort for the study of EI and all-cause mortality.

An empirical biomarker for log(EI) was developed that had a correlation of 0.73 with log(feeding study-consumed EI). The overall association between EI and mortality was nonsignificant. The association, however, depended on age (P = 0.009), with lower EI associated with lower mortality at younger ages, and also on preceding weight change history (P = 0.03). Among participants with stable or increasing weight, mortality hazard ratios (95% confidence intervals [CIs]) for a 12% lower EI were 0.66 (95% CI: 0.51, 0.87) at age 60, 0.84 (95% CI: 0.72, 0.98) at age 70, and 1.06 (95% CI: 0.87, 1.29) at age 80. Corresponding values for participants having preceding weight loss were 0.83 (95% CI: 0.61, 1.12) at age 60, 1.05 (95% CI: 0.87, 1.26) at age 70, and 1.33 (95% CI: 1.08, 1.63) at age 80. A previously considered EI biomarker, using a theoretical model for variation in body fat and fat-free mass components over time, gave similar results following rescaling.

Lower EI is associated with lower all-cause mortality among younger postmenopausal females with stable or increasing weight and with higher mortality among older females with weight loss.

This study was registered with clinicaltrials.gov as NCT00000611.

Allostatic load can reflect the body's response to chronic stress. However, little is known about the association between allostatic load and risk of breast cancer in postmenopausal women. This study used a large prospective cohort in the United States to examine the relationship between allostatic load and invasive breast cancer risk, and to evaluate the relationship by racial and ethnic identity and breast cancer subtypes.

Among 161,808 postmenopausal participants in Women's Health Initiative, eligible were a subsample of 27,393 postmenopausal women aged 50–79 years old, who enrolled from 1993 to 1998, had serum test biomarkers, and were followed for breast cancer incidence through February 2022. Allostatic load at enrollment was computed based on eight biomarkers from lab serum tests and a questionnaire about participants' prescription drug use. The associations between allostatic scores and risk of breast cancer (overall and by subtypes) were assessed using Cox proportional hazards models. The race and ethnic differences were examined.

Over a median follow-up time of 17.24 years, 1722 invasive breast cancer cases were identified. High allostatic load was associated with an increased risk of breast cancer (HR = 1.36, 95%CI: 1.20, 1.54 for third tertile vs first tertile, P_trend < 0.0001). Similar trends were found in White women and non-Hispanic women. Higher allostatic load was associated with hormone receptor-positive and HER2/Neu-negative breast cancer (HR = 1.54, 95%CI: 1.30, 1.80 for third tertile vs first tertile, P_trend < 0.0001).

In this study, we found that higher allostatic load was significantly associated with an increased risk of breast cancer in postmenopausal women.

Chronic psychological distress is associated with increased risk of cardiovascular disease (CVD) and investigators have posited inflammatory factors may be centrally involved in these relationships. However, mechanistic evidence and molecular underpinnings of these processes remain unclear, and data are particularly sparse among women. This study examined if a metabolite profile linked with distress was associated with increased CVD risk and inflammation-related risk factors.

A plasma metabolite-based distress score (MDS) of twenty chronic psychological distress-related metabolites was developed in cross-sectional, 1:1 matched case-control data comprised of 558 women from the Nurses’ Health Study (NHS; 279 women with distress, 279 controls). This MDS was then evaluated in two other cohorts: the Women’s Health Initiative Observational Cohort (WHI-OS) and the Prevención con Dieta Mediterránea (PREDIMED) trial. We tested the MDS's association with risk of future CVD in each sample and with levels of C-reactive protein (CRP) in the WHI-OS. The WHI-OS subsample included 944 postmenopausal women (472 CHD cases; mean time to event = 5.8 years); the PREDIMED subsample included 980 men and women (224 CVD cases, mean time to event = 3.1 years).

In the WHI-OS, a 1-SD increase in the plasma MDS was associated with a 20% increased incident CHD risk (odds ratio [OR] = 1.20, 95% CI: 1.04 – 1.38), adjusting for known CVD risk factors excluding total and HDL cholesterol. This association was attenuated after including total and HDL cholesterol. CRP mediated an average 12.9% (95% CI: 4.9% – 28%, p < 10^-15) of the total effect of MDS on CHD risk when adjusting for matching factors. This effect was attenuated after adjusting for known CVD risk factors. Of the metabolites in the MDS, tryptophan and threonine were inversely associated with incident CHD risk in univariate models. In PREDIMED, each one SD increase in the MDS was associated with an OR of 1.19 (95% CI: 1.00 – 1.41) for incident CVD risk, after adjusting all risk factors. Similar associations were observed in men and women. Four metabolites in the MDS were associated with incident CVD risk in PREDIMED in univariate models. Biliverdin and C36:5 phosphatidylcholine (PC) plasmalogen had inverse associations; C16:0 ceramide and C18:0 lysophosphatidylethanolamine (LPE) each had positive associations with CVD risk.

Our study points to molecular alterations that may underlie the association between chronic distress and subsequent risk of cardiovascular disease in adults.

Low diet quality, diabetes, and chronic inflammation are risk factors of liver cancer and chronic liver disease (CLD), but the extent to which insulinemic and inflammatory diets are independently associated with risk of liver cancer and CLD mortality is unknown.

We conducted a prospective cohort analysis among 78,356 postmenopausal women in the Women’s Health Initiative Observational Study. Two validated dietary indices, the empirical dietary index for hyperinsulinemia (EDIH) and the empirical dietary inflammation pattern (EDIP), were estimated from a food-frequency questionnaire. Incident cases of liver cancer and CLD mortality were adjudicated via review of medical records and linkage to National Death Index. Multivariable hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using Cox proportional hazards models, adjusted for age, diabetes, body mass index, and other covariates.

During a median 22.1 y of follow-up, we documented 176 primary liver cancer cases and 156 CLD mortality cases. EDIH was positively associated with incident liver cancer (HR_{Quartile 4 vs. Quartile 1} = 1.68; 95% CI: 1.00, 2.83; P-trend = 0.05) and CLD mortality (HR_{Q4 vs. Q1} = 2.28; 95% CI: 1.25, 4.15; P-trend = 0.02) in the multivariable model. EDIP was also positively associated with liver cancer (HR_{Q4 vs. Q1} = 1.88; 95% CI: 1.17, 3.03; P-trend = 0.009) and CLD mortality (HR_{Q4 vs. Q1} = 1.85; 95% CI: 1.09, 3.15; P-trend = 0.007). Estimates remained significant and robust in sensitivity analyses. Further analyses indicated positive associations for refined grains, processed meat, sugary beverages, and eggs, and inverse associations for coffee/tea and poultry.

Dietary insulinemic and inflammatory potentials were independently associated with higher risk of liver cancer and CLD mortality in U.S. postmenopausal women. These findings suggest a potential role for diet modification to reduce risk of liver cancer and CLD.