title: The prevalence of and risk factors associated with pterygium in a rural adult Chinese population: the Handan Eye Study.
abstract: OBJECTIVE
  To describe the prevalence and risk factors for pterygium in a rural adult Chinese population.
  
  
  METHODS
  A total of 7557 people aged 30 years and over were randomly selected from 13 villages in a rural county, Yongnian, within Handan district, Hebei Province of China. All eligible subjects were invited to undergo a comprehensive eye examination. A slit-lamp was used to examine the anterior segment for evidence of pterygium. Pterygium was graded for severity (G1 to G3) by visibility of episcleral vessels.
  
  
  RESULTS
  Of 6685 participants (88.5% of 7557) included in this study, pterygium was present in 401 (6.0%). Using direct standardization to the 2000 China population census for rural residents, the prevalence of pterygium was 7.1% (95% confidence interval [CI], 6.5-7.8%) among subjects aged 40+ years, and 4.8% (95% CI 4.3-5.3%) when including those aged 30-39 years. Pterygium was more common in men than in women (age-adjusted odds ratio [OR] 2.0, 95% CI 1.4-2.8). Prevalence increased with age (OR 1.8, 95% CI 1.6-2.1 per decade increase in age). Current smoking appeared to be protective (OR 0.5, 95% CI 0.4-0.7). Of eyes with any pterygium, 4.6% (95% CI 1.9-7.3%) had low vision.
  
  
  CONCLUSIONS
  Approximately one in ten adults had pterygium in this rural Chinese population. Age and male sex were positively, and current smoking negatively associated with the prevalence of pterygium.
authors.affiliation: Handan Eye Hospital, Hebei Province, China.
authors.forename: Lan Ping
authors.initials: LP
authors.lastname: Sun
authors.forename: Wei
authors.initials: W
authors.lastname: Lv
authors.forename: Yuan Bo
authors.initials: YB
authors.lastname: Liang
authors.forename: David S
authors.initials: DS
authors.lastname: Friedman
authors.forename: Xiao Hui
authors.initials: XH
authors.lastname: Yang
authors.forename: Li Xia
authors.initials: LX
authors.lastname: Guo
authors.forename: Yi
authors.initials: Y
authors.lastname: Peng
authors.forename: Ning Li
authors.initials: NL
authors.lastname: Wang
authors.forename: Jie Jin
authors.initials: JJ
authors.lastname: Wang
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D044466:Asian People / Q000208:ethnology*; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011625:Pterygium / Q000208:ethnology*; D012307:Risk Factors; D012424:Rural Population / Q000706:statistics & numerical data*; D017678:Sex Distribution