Associations Between Niacin Intake and Glaucoma in the National Health and Nutrition Examination Survey

Précis: This study examined the association between dietary niacin intake and glaucoma in the 2005-2008 National Health and Nutrition Examination Survey (NHANES). Increased niacin intake was associated with lower odds of glaucoma overall and among women. Purpose: To examine the association between dietary niacin intake and glaucoma in the 2005-2008 NHANES. Materials and Methods: This cross-sectional study included adult participants of the 2005-2008 NHANES. The exposure was dietary niacin intake, which was examined as a continuous and categorical variable. The outcome was glaucoma as defined by regraded disc images. Covariates included age, sex, race/ethnicity, education level, income, body mass index, smoking status, alcohol use, cardiovascular disease, diabetes mellitus, daily energy intake, vitamin B2 and B6 consumption, and macular degeneration. Adjusting for all covariates, logistic regression was performed to examine the association between niacin intake and glaucoma in the overall population and stratified by sex. Results: The weighted population included 5371 individuals (109,734,124 weighted), of whom 55 (1.0%) had glaucoma. Each 1 mg increase in niacin intake was associated with a 6% decreased odds of glaucoma odds [adjusted odds ratio (aOR) = 0.94, 95% CI = 0.90, 0.98]. Among women, increased niacin intake was associated with decreased odds of glaucoma both with niacin as a continuous (aOR = 0.89, 95% CI = 0.80, 0.99 per 1 mg increase in niacin intake) and binary variable (aOR = 0.35, 95% CI = 0.14, 0.90 for higher vs lower niacin intake). Conclusions: In the 2005-2008 NHANES population, higher levels of niacin intake were associated with decreased odds of glaucoma overall and in women. Further studies are needed to examine the potential protective effects of niacin on glaucoma risk.