Association between myopia, ultraviolet b radiation exposure, serum Vitamin D concentrations, and genetic polymorphisms in Vitamin Dmetabolic pathways in a multicountry european study

IMPORTANCE Myopia is becoming increasingly common globally and is associated with potentially sight-threatening complications. Spending time outdoors is protective, but the mechanism underlying this association is poorly understood. OBJECTIVE To examine the association ofmyopia with ultraviolet B radiation (UVB; directly associated with time outdoors and sunlight exposure), serum Vitamin D concentrations, and Vitamin D pathway genetic variants, adjusting for years in education. DESIGN, SETTING, AND PARTICIPANTS A cross-sectional, population-based random sample of participants 65 years and older was chosen from 6 study centers from the European Eye Study between November 6, 2000, to November 15, 2002. Of 4187 participants, 4166 attended an eye examination including refraction, gave a blood sample, and were interviewed by trained fieldworkers using a structured questionnaire.Myopia was defined as a mean spherical equivalent of -0.75 diopters or less. Exclusion criteria included aphakia, pseudophakia, late age-related macular degeneration, and vision impairment due to cataract, resulting in 371 participants withmyopia and 2797 without. EXPOSURES Exposure to UVB estimated by combiningmeteorological and questionnaire data at different ages, single-nucleotide polymorphisms in Vitamin Dmetabolic pathway genes, serum Vitamin D3 concentrations, and years of education. MAIN OUTCOMES AND MEASURES Odds ratios (ORs) of UVB, serum Vitamin D3 concentrations, Vitamin D single-nucleotide polymorphisms, andmyopia estimated from logistic regression. RESULT Of the included 3168 participants, the mean (SD) age was 72.4 (5) years, and 1456 (46.0%) were male. An SD increase in UVB exposure at age 14 to 19 years (OR, 0.81; 95%CI, 0.71-0.92) and 20 to 39 years (OR, 0.7; 95%CI, 0.62-0.93) was associated with a reduced adjusted OR ofmyopia; those in the highest tertile of years of education had twice the OR of myopia (OR, 2.08; 95%CI, 1.41-3.06). No independent associations betweenmyopia and serum Vitamin D3 concentrations nor variants in genes associated with Vitamin Dmetabolism were found. An unexpected finding was that the highest quintile of plasma lutein concentrations was associated with a reduced OR ofmyopia (OR, 0.57; 95%CI, 0.46-0.72). CONCLUSIONS AND RELEVANCE Increased UVB exposurewas associated with reduced myopia, particularly in adolescence and young adulthood. The association was not altered by adjusting for education.We found no convincing evidence for a direct role of Vitamin D inmyopia risk. The relationship between high plasma lutein concentrations and a lower risk ofmyopia requires replication.