The epidemiology of patients with pterygium in southern Taiwanese adults: TheChiayi survey

Purpose: To investigate patients with pterygium in different geographic regions and the associated risk factors in southern Taiwan. Methods: A clinical observation survey was conducted in Chiayi County, a rural area in southern Taiwan. The subjects aged 40 years and above underwent complete ocular examinations. Associated risks factors were evaluated, including gender, age, occupations, smoking, and geographical living regions by univariant and multivariant logistic regression analysis. Results: A total of 2197 participants (790 male, 36.0%) from 44 different villages were evaluated. In these, 554 participants (25.2%) have either unilateral or bilateral pterygium. Age is associated with the percentage of pterygium, and those aged between 60 and 69 had the highest percentage of 30.1% (p<0.0001). The gender effect was higher among men than women (OR=1.31, 95% CI: 1.08-1.60, p=0.006). The percentage of pterygium lived in plain, seaside, and mountainous areas were 22.6%, 32.6%, and 14.5% respectively. Geographical regions also showed that seaside area had the highest percentage of pterygium (seaside area OR=1.65, 95% CI: 1.35-2.03, and mountainous area OR=0.58, 95% CI: 0.35-0.95 compared with plain areas). Primary outdoor workers and residents with smoking history had relative higher risk for pterygium (OR=1.47, 95% CI: 1.17-1.86; OR=1.36, 95% CI: 1.02-1.83). Conclusions: The percentage of pterygium in southern Taiwan is about 25.2% among adults aged over 40 years in this survey. It is significantly higher in the age of 50 or more and in residents living in villages along the seaside than those living in the mountainous and the plain areas.