Associations of dietary fats and vitamin D with age-related maculopathy in population studies

Total or specific types of dietary fats have been hypothesized to increase the risk of age-related maculopathy (ARM) through several potential biologic mechanisms. Existing epidemiologic evidence is sparse and inconsistent for the relationship between ARM and dietary fat, specifically for types of fats, with the exception of intakes of o-3 polyunsaturated fat, present in fish, which is generally supportive of a protective association, especially for advanced stages. Vitamin D, naturally present in high levels in fish, may be an alternate explanation for previously observed inverse associations.; We investigated relationships of (1) amount and type of dietary fat, and (2) serum vitamin D and ARM, using an epidemiologic approach. In the first study, dietary intake of total and specific types of fats was estimated using a food frequency questionnaire (1994-98), and age-related macular degeneration (AMD) was ascertained using retinal photographs approximately seven years later (2001-2003). We noted that total fats were not associated with intermediate AMD in the overall population. However, associations differed by age. Total fat intake was associated with increased risk of intermediate AMD in women <75 years, which represented about three fourths of our population. Differently, we observed a decreased risk for AMD in women ≥75 years. Types of fat were associated differently with intermediate AMD: women with diets high in o-6 PUFA and o-3 PUFA had increased prevalence of intermediate AMD, whereas women with diets high in MUFA had a decreased prevalence of intermediate AMD.; Our second study was conducted to evaluate the associations between ARM and vitamin D, a fat-soluble nutrient. Recent reports have focused on the role of inflammation in the pathogenesis of early ARM. The anti-inflammatory properties of vitamin D suggest that higher vitamin D may be protective against ARM. We undertook this study in the Third National Health and Nutrition Examination Survey (NHANES III; N = 7,648). Our results suggest that increasing levels of serum vitamin D are inversely associated with overall early ARM. Since we provided the first scientific evidence of the associations of vitamin D and ARM, further investigations in prospective studies are needed for confirmation of these associations.