Association of dietary niacin intake with all-cause and cardiovascular mortality: National Health and Nutrition Examination Survey (NHANES) 2003-2018

The long-term health impacts of niacin are still debated, and the association between dietary niacin and mortality risk in populations hasn't been extensively explored. This study included 26,746 US adults aged 20 years or older from the National Health and Nutrition Examination Survey 2003-2018, with a median follow-up of 9.17 years. During this period, there were 3,551 all-cause deaths, including 1,096 cardiovascular deaths. Cox models were used to compare hazard ratios (HRs) for mortality among participants grouped into different dietary niacin intake quartiles. Participants with the highest dietary niacin intake had a lower risk of all-cause mortality (HR 0.74, 95%CI 0.63-0.86) compared to those in the lowest intake quartile. For cardiovascular mortality, the HR was 0.73 (95%CI 0.57-0.95) in the highest niacin intake quartile. A dose-response relationship was revealed between dietary niacin intake and mortality by restricted cubic spline. Subgroup analysis showed a significant interaction between dietary niacin intake and diabetes concerning all-cause mortality (P = 0.046). In this population-based cohort study, higher dietary niacin intake correlates with lower risk of all-cause and cardiovascular mortality among US adults. The influence of niacin intake on all-cause mortality appears to be more significant in non-diabetic individuals compared to those with diabetes.