Prevalence and associated factors for pterygium in rural people aged 50 years and above in Funing County, Jiangsu Province

Objective

To investigate the prevalence and associated risk factors for pterygium among people aged 50 years and above in Funing County, Jiangsu Province.

Methods

A cluster random sampling method was performed, the subjects aged 50 years or above were randomly selected from 30 survey sites in Funing County, Jiangsu Province.Questionnaires, visual acuity tests, the examinations of eye surface, anterior segment, fundus examinations were conducted.Pterygium was diagnosed and graded clinically by slit lamp examination.The risk factors were acquired from questionnaires and analyzed by the multivariate logistic regression analysis.This study protocol was approved by Ethic Committee of Affiliated Hospital of Nantong University (NO.2010-05). Written informed consent was obtained from each subject prior to entering study cohort.

Results

A total of 6 145 persons aged 50 years and above were enumerated, and actually 5 947 (96.8%) participants were examined.Among them, 1 950 cases were diagnosed as pterygium in either eye and 1 228 cases were diagnosed as pterygium in binoculus, which was equivalent to the 32.79%[95% confidence interval(CI): 31.60%-33.98%] of pterygium in either eye and 20.65% (95% CI: 19.62%-21.68%) in bilateral pterygium.Among 2 467 male subjects, 838 were diagnosed as pterygium(33.97%, 95% CI: 32.10%-35.84%). Among 3 480 female subjects, 1 112 were diagnosed as pterygium (31.95%, 95% CI: 30.40%-33.51%). There was no significant difference in the prevalence of pterygium between genders (P=0.135). Multivariate Logistic analysis showed that, older age (50~<60 years: odds ratio [OR]=1.00; 60~<70 years: OR=1.54, P<0.001; 70~<80 years, OR=1.83, P<0.001; ≥80 years: OR=1.99, P<0.001), low educational level (no education: OR=1.00; <primary: OR=0.87, P=0.031; primary education: OR=0.72, P=0.002; ≥secondary education: OR=0.63, P=0.002), farmer occupations (OR=1.34, P=0.020), and long outdoor work time (OR=1.13, P=0.026) were independent risk factors for pterygium.Gender, marriage, income, hypertension, diabetes, smoking and alcohol use history were not associated with pterygium (all at P>0.05).

Conclusions

The prevalence of pterygium in Funing County is 32.79% in people aged 50 years and above.The high prevalence of pterygium may be associated with older age, low education level and long outdoor work time.