Daily folate consumption is associated with reduced all-cause and cardiovascular disease mortality among US adults with diabetes, prediabetes, or insulin resistance

We hypothesized that daily folate consumption may have a beneficial effect on mortality among adults with dysglycemia. This prospective cohort study was conducted on 9266, 12,601, and 16,025 US adults with diabetes, prediabetes, and insulin resistance (IR; homeostasis model assessment of IR >2.6), respectively, from the National Health and Nutrition Examination Survey Ⅲ and 1999-2018. Daily folate consumption was obtained from dietary recall. All-cause, cardiovascular disease (CVD), and cancer mortality were obtained by linking to the National Death Index Mortality Data. During 117,746.00, 158,129.30, and 210,896.80 person-years of follow-up, 3356 (1053 CVD and 672 cancer), 3796 (1117 CVD and 854 cancer), and 4340 (1286 CVD and 928 cancer) deaths occurred among participants with diabetes, prediabetes, and IR, respectively. After multivariate adjustment, each 1-unit increase in ln-transformed daily folate consumption was linearly associated with 7.1% (hazard ratio [HR], 0.929; 95% confidence interval [CI], 0.914-0.945), 12.4% (HR, 0.886; 95% CI, 0.860-0.912), and 6.4% (HR, 0.936; 95% CI, 0.903-0.972) decreases in risk of all-cause, CVD, and cancer mortality, respectively, among participants with diabetes. Among participants with prediabetes, each 1-unit increase in ln-transformed daily folate consumption was linearly associated with 3.6% (HR, 0.964; 95% CI, 0.949-0.980), 7.8% (HR, 0.922; 95% CI, 0.895-0.949), and 3.6% (HR, 0.964; 95% CI, 0.932-0.997) decreases in risk of all-cause, CVD, and cancer mortality, respectively. Among participants with IR, each 1-unit increase in ln-transformed daily folate consumption was linearly associated with 5.7% (HR, 0.943; 95% CI, 0.929-0.956) and 9.0% (HR, 0.910; 95% CI, 0.885-0.933) decreases in risk of all-cause and CVD mortality, respectively. Increased daily folate consumption may be beneficial in reducing all-cause and CVD mortality of adults with dysglycemia. More research is needed to explore the underlying mechanisms.