title: Association Between Myopia, Ultraviolet B Radiation Exposure, Serum Vitamin D Concentrations, and Genetic Polymorphisms in Vitamin D Metabolic Pathways in a Multicountry European Study.
abstract: OBJECTIVE
  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 of myopia 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.
  
  
  METHODS
  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 with myopia and 2797 without.
  
  
  METHODS
  Exposure to UVB estimated by combining meteorological and questionnaire data at different ages, single-nucleotide polymorphisms in vitamin D metabolic pathway genes, serum vitamin D3 concentrations, and years of education.
  
  
  METHODS
  Odds ratios (ORs) of UVB, serum vitamin D3 concentrations, vitamin D single-nucleotide polymorphisms, and myopia estimated from logistic regression.
  
  
  RESULTS
  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 of myopia; 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 between myopia and serum vitamin D3 concentrations nor variants in genes associated with vitamin D metabolism were found. An unexpected finding was that the highest quintile of plasma lutein concentrations was associated with a reduced OR of myopia (OR, 0.57; 95% CI, 0.46-0.72).
  
  
  CONCLUSIONS
  Increased UVB exposure was 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 in myopia risk. The relationship between high plasma lutein concentrations and a lower risk of myopia requires replication.
authors.affiliation: Department of Ophthalmology, King's College London, London, United Kingdom2Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom.
authors.forename: Katie M
authors.initials: KM
authors.lastname: Williams
authors.affiliation: School of Environmental Sciences, University of East Anglia, East Anglia, United Kingdom.
authors.forename: Graham C G
authors.initials: GC
authors.lastname: Bentham
authors.affiliation: Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom.
authors.forename: Ian S
authors.initials: IS
authors.lastname: Young
authors.affiliation: Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom.
authors.forename: Ann
authors.initials: A
authors.lastname: McGinty
authors.affiliation: Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom.
authors.forename: Gareth J
authors.initials: GJ
authors.lastname: McKay
authors.affiliation: Centre for Experimental Medicine, Institute of Clinical Science, Queen's University Belfast, Belfast, United Kingdom.
authors.forename: Ruth
authors.initials: R
authors.lastname: Hogg
authors.affiliation: Department of Ophthalmology, King's College London, London, United Kingdom.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Hammond
authors.affiliation: Centre for Experimental Medicine, Institute of Clinical Science, Queen's University Belfast, Belfast, United Kingdom.
authors.forename: Usha
authors.initials: U
authors.lastname: Chakravarthy
authors.affiliation: Department of Epidemiology and Biostatistics, National Institute for Health Development, Tallinn, Estonia.
authors.forename: Mati
authors.initials: M
authors.lastname: Rahu
authors.affiliation: Eye Department, University of Bergen, Bergen, Norway.
authors.forename: Johan
authors.initials: J
authors.lastname: Seland
authors.affiliation: Department of Ophthalmology, Hôtel-Dieu de Paris, Paris Descartes University, Paris, France.
authors.forename: Gisele
authors.initials: G
authors.lastname: Soubrane
authors.affiliation: Ophthalmology Clinic, University of Verona, Verona, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Tomazzoli
authors.affiliation: Department of Ophthalmology, Aristotle University of Thessaloniki School of Medicine, Thessaloniki, Greece.
authors.forename: Fotis
authors.initials: F
authors.lastname: Topouzis
authors.affiliation: Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Astrid E
authors.initials: AE
authors.lastname: Fletcher
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D004247:DNA / Q000235:genetics*; D005060:Europe / Q000453:epidemiology; D006801:Humans; D053858:Metabolic Networks and Pathways; D008875:Middle Aged; D009216:Myopia / Q000097:blood* / Q000453:epidemiology / Q000235:genetics; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D011159:Population Surveillance; D012029:Refraction, Ocular / Q000528:radiation effects*; D012189:Retrospective Studies; D014466:Ultraviolet Rays / Q000009:adverse effects*; D014792:Visual Acuity; D014807:Vitamin D / Q000097:blood*; D055815:Young Adult
chemical_list: D014807:Vitamin D; D004247:DNA