title: Prevalence and associated factors for pterygium in a rural adult population (the Southern Harbin Eye Study).
abstract: OBJECTIVE
  To estimate the prevalence of pterygium and identify associated risk factors in a Southern Harbin population at low altitude in a cold climate.
  
  
  METHODS
  A prospective population-based survey was conducted in 2006. A stratified, clustered, randomized sampling procedure was used to select 5057 subjects aged 50 years and older. Pterygia were diagnosed and graded, and the association between pterygium and astigmatism was investigated. Risk factors associated with pterygium were evaluated with logistic regression models.
  
  
  RESULTS
  A total of 5057 persons aged 50 to 96 years (91.0% of the eligible population) who were residents of Southern Harbin, Heilongjiang Province, China, participated in the study, and 323 (6.4%) had at least 1 pterygium. The prevalence of pterygium in the unilateral and bilateral eyes of the participants was 3.7% and 2.6%, respectively. The presence of a pterygium was significantly associated with the presence of astigmatism (cylinder ≥ ± 0.5 diopters, P < 0.001). Pterygium was independently associated with male sex (odds ratio 1.73; 95% confidence interval, 1.37-2.19) and smoking (odds ratio 1.90; 95% confidence interval, 1.51-2.35) (P < 0.001).
  
  
  CONCLUSIONS
  This study details pterygium in a rural population of Harbin at low altitude in a cold climate. The prevalence of pterygium in the population is lower than that reported in other regions of the world. The primary causative factors were related to male sex and smoking, the latter of which is easily preventable. Public health schemes to address this serious health issue are urgently needed.
authors.affiliation: Department of Ophthalmology, First Affiliated Hospital, Harbin Medical University, Harbin, China. lzj6515@sina.com
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Li
authors.forename: Hao
authors.initials: H
authors.lastname: Cui
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000453:epidemiology; D002681:China / Q000453:epidemiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D011625:Pterygium / Q000453:epidemiology*; D012307:Risk Factors; D012424:Rural Population / Q000706:statistics & numerical data*; D012737:Sex Factors; D011795:Surveys and Questionnaires