Abstract
Purpose::
To describe the prevalence of pterygium and its risk factors in the urban Malay population of Singapore
Methods::
A population-based cross-sectional study of 3,280 (78.7% response rate) Malays aged 40-80 years in Singapore. The population was selected based on an age-stratified random sampling procedure of Malay people living in the south-western part of Singapore. Participants had a standardized interview, examination and ocular imaging at a centralized study clinic. Pterygium was diagnosed and graded clinically by slit-lamp examination as Grade 1 (atrophic), Grade 2 ( intermediate) and Grade 3 ( fleshy), and also classified as either unilateral or bilateral pterygia.
Results::
Data were available on 3266 participants. There were 508 people with any pterygia, 289 with unilateral and 219 with bilateral pterygia. The overall prevalence was 15.6% (95% confidence intervals, 14.3, 16.8). The prevalence increased with age (7.1%,15.0%, 19.0% and 22.0% among participants aged 40-49, 50-59, 60-69 and 70-79 years, respectively (p for trend <0.001) and was higher in men than women (20.4% vs 11.1%, p<0.001). After adjusting for age and gender, pterygium was more common in subjects with elementary education or lower (odds ratio[OR] 2.24, 95%CI, 1.33, 3.77), among subjects with a history of smoking(OR: 1.52, 95%CI, 1.15, 2.01), hypertension ( OR: 1.56, 95%CI, 1.25, 1.94) and previous myocardial infarction (OR: 1.43, 95%CI, 1.01, 2.03) and among service workers and cleaners (OR: 1.76,95%CI, 1.13, 2.75) and production workers (OR: 2.27, 95%CI,1.41,3.65) as compared to professionals and office workers. Grade 3 (n=92) pterygium was independently associated with male gender but not related to age. Grade 3 pterygium was more common in subjects with lower educational attainment and in those who were unemployed.
Conclusions::
The prevalence of pterygium in Singapore is 15.6% among Malays aged 40 years and older. This rate is higher than most other population-based studies. Independent associations with male gender, older age, certain occupations as well as systemic and medical factors suggest a multi-factorial etiology for this condition.
Keywords: Pterygium • clinical (human) or epidemiologic studies: prevalence/incidence • clinical (human) or epidemiologic studies: risk factor assessment