Dietary niacin Intake and its association with all-cause and cardiovascular mortality rates in individuals with metabolic syndrome.

Background: Individuals with metabolic syndrome face elevated cardiovascular and mortality risks, and there is ongoing debate regarding the cardiovascular effects of niacin and its impact on the prognosis of metabolic syndrome.

Exposure: Levels of dietary niacin intake based on 24-hour dietary recall.

Methods: Kaplan-Meier survival curves were used to compare survival status among quartiles of dietary niacin intake. Weighted Cox proportional hazards models and restricted cubic splines were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk of all-cause and CVD mortality associated with the exposure.

Results: This cohort study included 8,744 participants, and during a median follow-up period of 106 months, 1,552 (17.7%) deaths were recorded, with 511 attributed to cardiovascular disease. Kaplan-Meier curves comparing quartiles of dietary niacin intake showed significant differences in both all-cause and cardiovascular mortality rates (log-rank p < 0.001). In the fully adjusted model, the highest quartile of dietary niacin intake was associated with HRs of 0.68 (95% CI: 0.54, 0.87, P = 0.002) for all-cause mortality and 0.63 (95% CI: 0.39, 0.78, P < 0.001) for cardiovascular mortality.

Conclusion: The results of this cohort study suggest that higher dietary niacin intake is associated with reduced cardiovascular and all-cause mortality risks in the metabolic syndrome population. Furthermore, there appears to be a dose-response relationship between dietary niacin intake and the risks of all-cause and cardiovascular mortality.