Dietary Niacin and Open-Angle Glaucoma: The Korean National Health and Nutrition Examination Survey

Glaucoma is a leading cause of loss of sight. High intraocular pressure (TOP) is the most critical risk factor. However, glaucoma develops even within a normal IOP range. Normal tension glaucoma (NTG) is more common in Asia, whereas high tension glaucoma is more common in Western countries. The pathogenesis of glaucoma, especially NTG, is poorly understood. We evaluated the correlation between dietary nutrient intake and glaucoma using data from subjects >= 40 years old from the ongoing, nationwide, population-based study, the Korean National Health and Nutrition Examination Survey V (2008-2012). Dietary intake was determined using the 24 h recall method. Fiber (g/day), ash (g/day), calcium (mg/day), phosphorus (mg/day), iron (mg/day), sodium (mg/day), potassium (mg/day), beta-Carotene (mu g/day), retinol (mu g/day), vitamin A (mu g Retinol Equivalents/day), thiamine (mg/day), riboflavin (mg/day), niacin (mg/day), and vitamin C (mg/day) were included in nutrient intake data. All nutrient intake was divided into quartiles. The mean IOP did not differ according to quartiles from any nutrients (all p > 0.05). After adjusting for age, gender, income status, education level, smoking, alcohol consumption, physical activity, diabetes, hypertension, IOP, and total energy, the intake of niacin was associated with glaucoma (p = 0.013). Among subjects with TOP <= 21 mmHg, only niacin was related to glaucoma in a multivariate analysis (p = 0.022). Dietary nutrient intake was associated with open-angle glaucoma independent of TOP. Individuals with NTG showed lower intake of niacin among nutrients. This finding suggests the possibility that proper diet counseling may be another modifiable factor, aside from IOP, particularly among patients with NTG.