The role of nutrition in erectile dysfunction (ED) is gaining attention, yet the specific association with dietary niacin—a key nutrient for vascular function—remains unclear, highlighting a significant evidence gap. We hypothesize that niacin supports erectile physiology and that its relationship with ED risk may be a threshold association rather than a simple linear correlation. We used data on erectile function and dietary intake of niacin from the 2001 to 2004 National Health and Nutrition Examination Survey. Unadjusted analysis and adjusted logistic regression models were used to explore the association between niacin intake and ED. Generalized additive models were used to examine the presence of nonlinear relationships. Upon finding a nonlinear relationship, a recursive algorithm was used to calculate the inflection point. In the model adjusted for all covariates, the ORs (95% CI) for the association between niacin intake and ED were 0.984(0.973, 0.996). A generalized additive model confirmed a nonlinear, threshold relationship between niacin intake and ED, finding an inflection point (47.5 mg/d). When the daily intake of niacin is less than 47.5 mg, increased niacin intake was associated with a lower prevalence of ED. When the daily intake of niacin exceeds 47.5 mg, this phenomenon is not observed. An inverse, nonlinear association was observed between dietary niacin intake and ED in U.S. adults. Intake below approximately 47.5 mg/day was associated with a lower ED prevalence. These findings suggest an association that warrants further investigation in longitudinal studies to clarify any causal relationship.
Zheng et al. (Sun,) studied this question.