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.