Prevalence of pterygium in a population in Northern Japan: the Locomotive Syndrome and Health Outcome in Aizu Cohort Study

PURPOSE: The aim of the study was to determine the prevalence and risk factors for pterygium in a population aged 40–74 years in Fukushima Prefecture, Japan. METHODS: Of 4185 citizens of the towns of Minamiaizu-machi and Tadami-machi, 2312 (55.2%) gave consent to an ocular examination during a health examination. Pterygium was diagnosed when a radially oriented fibrovascular lesion growing over the limbus into the cornea was observed. Eyes with a history of pterygium excision were also diagnosed with pterygium. Prevalence and factors associated with pterygium were investigated. RESULTS: Of the 2312 subjects, 101 (4.4%; 95% confidence interval, 3.6–5.3%) had pterygium in at least 1 eye. The average age (±SD) of the subjects was 64.3 ± 8.0 years. Gender, age, outdoor job history and smoking history were examined as possible associated factors, but only age was found to be significantly associated with pterygium in logistic regression analysis. CONCLUSION: The prevalence of pterygium was 4.4% in the study population. This low rate may be due to the northern latitude of these towns. Age was associated with a risk of pterygium, but gender and outdoor job history were not associated with onset of pterygium in this study.