Abstract
Dietary niacin, a vital nutrient needed for the metabolism of mitochondrial energy, has been linked to nonalcoholic fatty liver disease and cancer mortality. There is, however, little information available about how dietary niacin intake affects mortality risk in the general population. Therefore, our aim was to investigate the relationship between dietary niacin consumption and all-cause and cardiovascular mortality in the general population. 39428 participants from the National Health and Nutrition Examination Survey (NHANES) 1999-2008 were analyzed. Multivariate Cox proportional hazards regression models, restricted cubic splines (RCS), trend tests, subgroup analysis and inflection point analysis were employed. Over a median follow-up period of 110 months, all-cause mortality accounted for 15.1% of cases, and cardiovascular mortality accounted for 3.387%. During Cox proportional hazards regression analysis, no linear trend was observed between dietary niacin intake and all-cause (P for trend = 0.001) or cardiovascular mortality (P for trend = 0.008) after adjusting for confounding factors. RCS revealed a non-linear association between dietary niacin intake and all-cause mortality (Non-linear P=0.001), but linear association between dietary niacin intake and cardiovascular mortality (Non-linear P = 0.384) when 99.9% of the data was shown. In the inflection point analysis, the HR of all-cause mortality was 0.995 (95% CI:0.991–0.995, P = 0.039) in general population with dietary niacin intake of <54.6 mg/day and 1.007 (95% CI:0.993–1.020, P = 0.296) in general population with dietary niacin intake of ≥54.6 mg/day. The effect of dietary niacin intake was consistent across most subgroups in terms of all-cause and cardiovascular mortality, with no significant interaction with randomized factors (all-cause mortality: P for interaction = 0.047–0.719, cardiovascular mortality: P for interaction = 0.257–0.784). Dietary niacin intake was nonlinearly associated with all-cause mortality but linearly associated with cardiovascluar mortality in general population of United States.