Background: Plant-based diets have been associated with lower risk of type 2 diabetes mellitus and cardiovascular disease (CVD) and are recommended for both health and environmental benefits. However, the association between changes in plant-based diet quality and mortality remains unclear. Methods: We investigated the associations between 12-year changes (from 1986 to 1998) in plant-based diet quality assessed by 3 plant-based diet indices (score range, 18–90)—an overall plant-based diet index (PDI), a healthful PDI, and an unhealthful PDI—and subsequent total and cause-specific mortality (1998–2014). Participants were 49 407 women in the Nurses’ Health Study (NHS) and 25 907 men in the Health Professionals Follow-Up Study (HPFS) who were free from CVD and cancer in 1998. Multivariable-adjusted Cox proportional-hazards models were used to estimate hazard ratios (HRs) and 95% CIs. Results: We documented 10 686 deaths including 2046 CVD deaths and 3091 cancer deaths in the NHS over 725 316 person-years of follow-up and 6490 deaths including 1872 CVD deaths and 1772 cancer deaths in the HPFS over 371 322 person-years of follow-up. Compared with participants whose indices remained stable, among those with the greatest increases in diet scores (highest quintile), the pooled multivariable-adjusted HRs for total mortality were 0.95 (95% CI, 0.90–1.00) for PDI, 0.90 (95% CI, 0.85–0.95) for healthful PDI, and 1.12 (95% CI, 1.07–1.18) for unhealthful PDI. Among participants with the greatest decrease (lowest quintile), the multivariable-adjusted HRs were 1.09 (95% CI, 1.04–1.15) for PDI, 1.10 (95% CI, 1.05–1.15) for healthful PDI, and 0.93 (95% CI, 0.88–0.98) for unhealthful PDI. For CVD mortality, the risk associated with a 10-point increase in each PDI was 7% lower (95% CI, 1–12%) for PDI, 9% lower (95% CI, 4–14%) for healthful PDI, and 8% higher (95% CI, 2–14%) for unhealthful PDI. There were no consistent associations between changes in plant-based diet indices and cancer mortality. Conclusions: Improving plant-based diet quality over a 12-year period was associated with a lower risk of total and CVD mortality, whereas increased consumption of an unhealthful plant-based diet was associated with a higher risk of total and CVD mortality.

OBJECTIVE: We evaluated the associations between changes in plant-based diets and subsequent risk of type 2 diabetes. RESEARCH DESIGN AND METHODS: We prospectively followed 76,530 women in the Nurses’ Health Study (NHS) (1986–2012), 81,569 women in NHS II (1991–2017), and 34,468 men in the Health Professionals Follow-up Study (1986–2016). Adherence to plant-based diets was assessed every 4 years with the overall plant-based diet index (PDI), healthful PDI (hPDI), and unhealthful PDI (uPDI). We used multivariable Cox proportional hazards models to estimate hazard ratios (HRs). We pooled results of the three cohorts using meta-analysis. RESULTS: We documented 12,627 cases of type 2 diabetes during 2,955,350 person-years of follow-up. After adjustment for initial BMI and initial and 4-year changes in alcohol intake, smoking, physical activity, and other factors, compared with participants whose indices remained relatively stable (±3%), participants with the largest decrease (>10%) in PDI and hPDI over 4 years had a 12–23% higher diabetes risk in the subsequent 4 years (pooled HR, PDI 1.12 [95% CI 1.05, 1.20], hPDI 1.23 [1.16, 1.31]). Each 10% increment in PDI and hPDI over 4 years was associated with a 7–9% lower risk (PDI 0.93 [0.91, 0.95], hPDI 0.91 [0.87, 0.95]). Changes in uPDI were not associated with diabetes risk. Weight changes accounted for 6.0–35.6% of the associations between changes in PDI and hPDI and diabetes risk. CONCLUSIONS: Improving adherence to overall and healthful plant-based diets was associated with a lower risk of type 2 diabetes, whereas decreased adherence to such diets was associated with a higher risk.

Objective To determine whether a healthful plant-based diet is related to lower stroke risk, we examined the associations of plant-based diet quality with risk of total, ischemic, and hemorrhagic stroke. Methods The participants were 73,890 women in Nurses9 Health Study (NHS; 1984–2016), 92,352 women in NHSII (1991–2017), and 43,266 men in Health Professionals Follow-Up Study (1986–2012) without cardiovascular disease and cancer at baseline. Plant-based diet quality was evaluated by the overall plant-based diet index (PDI), the healthful PDI (hPDI), and the unhealthful PDI (uPDI). Participants who reported that their meat and/or fish intakes were 0 or <1 serving per month were categorized as vegetarians, and others were classified as nonvegetarians. Strokes with available medical records were subtyped as ischemic or hemorrhagic. Results During the follow-up, 6,241 total stroke cases (including 3,015 ischemic and 853 hemorrhagic strokes) were documented. Compared to participants with the lowest PDIs, among participants with the highest PDIs, the hazard ratios (HRs) for total stroke were 0.94 (95% confidence interval 0.86–1.03) for PDI, 0.90 (0.83–0.98) for hPDI, and 1.05 (0.96–1.15) for uPDI. Participants in the highest hPDI showed marginally lower HR for ischemic stroke (0.92 [0.82–1.04]) and no consistent associations for hemorrhagic stroke. We observed no association between a vegetarian diet and total stroke (1.00 [0.76–1.32]), although the number of cases was small. Conclusion Lower risk of total stroke was observed by those who adhered to a healthful plant-based diet.

A healthful plant-based diet is associated with lower risk of cardiometabolic diseases. However, it is still unclear whether such benefits are due to its favorable effects on adiposity-associated biomarkers. We investigated the associations between biomarkers and 3 plant-based diet indices: an overall plant-based diet index (PDI); a healthful plant-based diet index (hPDI); and an unhealthful plant-based diet index (uPDI). In the Nurses’ Health Study II, 831 women [baseline mean age: 45 y; body mass index (BMI, kg/m²): 24.6] were randomly selected from those who provided 2 blood samples in 1996–1999 and 2010–2011 to measure plasma concentrations of adiponectin, leptin, soluble leptin receptor (sOB-R), insulin, retinol-binding protein-4, high-sensitivity C-reactive protein (hsCRP), and interleukin-6 (IL-6). Plant-based diet indices were derived from semiquantitative food frequency questionnaires assessed at each blood collection. Linear mixed models were used to evaluate cross-sectional associations, and general linear models were used to evaluate longitudinal associations. In cross-sectional analyses with multivariable adjustment including BMI, higher hPDI was associated with lower concentrations of leptin, insulin, and hsCRP, and higher adiponectin and sOB-R concentrations (biomarker differences per 10-point higher hPDI: −7.2%, −10.0%, −13.6%, 3.0%, and 1.9%, respectively; P ≤ 0.025). A higher uPDI was associated with higher concentrations of leptin and insulin (4.4% and 4.8%, respectively; P ≤ 0.048). In longitudinal analyses with multivariable adjustment including weight change, an increase in hPDI (improved plant-based diet quality) was inversely associated with changes in leptin and hsCRP (biomarker changes per 10-point hPDI increase: −7.7% and −17.8%, respectively; P ≤ 0.005), whereas an increase in uPDI (worsened plant-based diet quality) was positively associated with changes in leptin, hsCRP, and IL-6 (10.1%, 13.5%, and 12.4%, respectively; P ≤ 0.021). Adherence to a healthful plant-based diet is associated with favorable long-term changes in adiposity-associated biomarker concentrations in women.

OBJECTIVE: To identify sleep duration trajectories from early to middle adulthood and their associations with incident type 2 diabetes.RESEARCH DESIGN AND METHODS: Using a group-based modeling approach, we identified sleep duration trajectories based on sleep duration in ages 20–25, 26–35, 36–45, and 46+ years, which were retrospectively assessed in 2009 among 60,068 women from the Nurses’ Health Study II (median age 54.9 years) who were free of diabetes, cardiovascular disease, and cancer. We investigated the prospective associations between sleep duration trajectories and diabetes risk (2009–2017) using multivariable Cox proportional hazards models.RESULTS: We documented 1,797 incident diabetes cases over a median follow-up of 7.8 years (442,437 person-years). Six sleep duration trajectories were identified: persistent 5-, 6-, 7-, or 8-h sleep duration and increased or decreased sleep duration. After multivariable adjustment for diabetes risk factors, compared with the persistent 7-h sleep duration group, the hazard ratio was 1.43 (95% CI 1.10, 1.84) for the 5-h group, 1.17 (1.04, 1.33) for the 6-h group, 0.96 (0.84, 1.10) for the 8-h group, 1.33 (1.09, 1.61) for the increased sleep duration group, and 1.32 (1.10, 1.59) for the decreased sleep duration group. Additional adjustment for time-updated comorbidities and BMI attenuated these associations, although a significantly higher risk remained in the decreased sleep duration group (1.24 [1.03, 1.50]).CONCLUSIONS: Persistent short sleep duration or changes in sleep duration from early to middle adulthood were associated with higher risk of type 2 diabetes in later life. These associations were weaker after obesity and metabolic comorbidities were accounted for.

Few studies have evaluated the association between a healthful plant-based diet and health-related quality of life (HRQoL). We followed 50 290 women in the Nurses’ Health Study (NHS; 1992–2000) and 51 784 women in NHSII (1993–2001) for 8 years to investigate changes in plant-based diet quality in relation to changes in physical and mental HRQoL. Plant-based diet quality was assessed by three plant-based diet indices: overall plant-based diet index (PDI), healthful PDI (hPDI) and unhealthful PDI (uPDI). Physical and mental HRQoL were measured by physical component score (PCS) and mental component score (MCS) of the 36-Item Short Form Health Survey. Diet was assessed 2 years before the HRQoL measurements and both were updated every 4 years. The associations between 4-year changes in PDIs and HRQoL were evaluated. Each 10-point increase in PDI was associated with an improvement of 0·07 (95 % CI 0·01, 0·13) in PCS and 0·11 (95 % CI 0·05, 0·16) in MCS. A 10-point increase in hPDI was associated with an increment of 0·13 (95 % CI 0·08, 0·19) in PCS and 0·09 (95 % CI 0·03, 0·15) in MCS. Conversely, a 10-point increase in uPDI was associated with decreases in PCS and MCS (−0·07 (95 % CI −0·12, −0·02) and −0·10 (95 % CI −0·16, −0·05), respectively). Compared with a stable diet, an increase in hPDI was significantly associated with improvements in physical HRQoL in older women and with mental HRQoL in younger women. In conclusion, adherence to a healthful plant-based diet was modestly associated with improvements in both physical and mental dimensions of HRQoL.