title: Is sunlight exposure a risk factor for age-related macular degeneration? A systematic review and meta-analysis.
abstract: BACKGROUND
  Epidemiologists have recently investigated sunlight exposure as a risk factor for age-related macular degeneration (AMD), but there remains an ongoing dispute over this association due to insufficient evidence and unreliable data.
  
  
  OBJECTIVE
  To analyse comprehensively the epidemiological literature concerning the association between AMD and sunlight exposure.
  
  
  METHODS
  We systematically reviewed the epidemiological literature concerning the association between AMD and sunlight exposure. An electronic search was performed of PubMed, Web of Science and CNKI, which was supplemented by hand searching. The selection of studies, data abstraction and quality assessment were performed independently by three reviewers. After these steps, we performed a random-effects meta-analysis, followed by subgroup analysis and sensitivity analysis, including a random-effects meta-regression for study-speciﬁc covariates.
  
  
  RESULTS
  Fourteen studies were identified. Twelve studies identified an increasing risk of AMD with greater sunlight exposure, six of which reported significant risks. The pooled OR was 1.379 (95% CI 1.091 to 1.745). The subgroup of non-population-based studies revealed a significant risk (OR 2.018, 1.248 to 3.265, p=0.004). We identified the gross domestic product (GDP) per capita (p=0.048), but not the latitude (p=0.21), as a factor that led to heterogeneity according to the meta-regression.
  
  
  CONCLUSIONS
  The epidemiological literature published to date indicates that individuals with more sunlight exposure are at a significantly increased risk of AMD. The OR significantly decreased with increasing GDP per capita.
authors.affiliation: School of Public Health, China Medical University, Shenyang, Liaoning, People's Republic of China.
authors.forename: Guo-Yuan
authors.initials: GY
authors.lastname: Sui
authors.forename: Guang-Cong
authors.initials: GC
authors.lastname: Liu
authors.forename: Guang-Ying
authors.initials: GY
authors.lastname: Liu
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Gao
authors.forename: Yan
authors.initials: Y
authors.lastname: Deng
authors.forename: Wen-Ying
authors.initials: WY
authors.lastname: Wang
authors.forename: Shu-Hui
authors.initials: SH
authors.lastname: Tong
authors.forename: Lie
authors.initials: L
authors.lastname: Wang
mesh_terms: D004781:Environmental Exposure / Q000009:adverse effects*; D006801:Humans; D008266:Macula Lutea / Q000528:radiation effects*; D008268:Macular Degeneration / Q000209:etiology*; D011832:Radiation Injuries / Q000209:etiology*; D012307:Risk Factors; D013472:Sunlight / Q000009:adverse effects*