| Background:A pterygium is a triangular wedge of fibrovascular conjunctival tissue that typically starts on the nasal conjunctiva and extends onto the cornea. It may cause cosmetic concerns, irritation, and even visual impairment. Its exact etiology is unknown. Variable prevalence and risk factors of pterygia have been reported worldwide, and inconsistence is not uncommon. Pterygia can coexist with ocular malignancy, and surgical excision comes with a relatively high recurrence rate, establishing prevention measures for pterygia is of great concern to all investigators. Growing knowledge of the risk and preventive factors may help curb the prevalence of pterygia in the future.Objective:To investigate the prevalence and associated risk factors of pterygia in Han and Tibetan population in Qinghai, China.Method:A cross-sectional study was carried out in four regions of Qinghai province from 2016-7 to 2016-8. A multistage and stratified sampling method was conducted to select representative samples. Demographic characteristics, life style and medical history were collected. Anterior segment examination was performed without pupil dilation using a slit lamp. Risk factors associated with pterygium were screened in logistic regression models.Result:Among 4711 participants with an average age of 44 years old (8-83),2594 (55.1%) were Han and 2117 (44.9%) were Tibetan ethnicity. Pterygia were found in 391 participants with an overall prevalence of 8.3%.5.3%(n=248) were unilateral and 3.0%(n=143) were bilateral. The age-sex adjusted prevalence of population older than 30 was 8.7%. Multivariate analysis indicated that age(p for trend＜0.001), female gender (p＜0.001), rural area (p=0.02), outdoor occupation (p=0.001), hypertension (p=0.046) and hyperopia (p=0.049) were significantly associated with pterygia, and high education level (p=0.003) was an protective factor. Only high MBI (p=0.013) had significant positive association with bilateral pterygia. In male participants, age (p<0.001), outdoor occupation (p<0.001), hypertension (p=0.01) were significant risk factors of pterygia, and current smoker (p=0.02) decreased the prevalence. However, multivariate analysis did not show significant association between smoke index and pterygia (p=0.15). Among females, age (p<0.001) and rural area (p<0.001) were positively associated with pterygia, and high education level (p=0.003) was a preventive factor. There was no significant difference (p=0.07) between urban residents and rural migrants who moved to urban area in their first decade of life. Risk was higher among participants who lived more than 10 years in countryside, but the OR value did not increase according to the time they lived there.Conclusion:This cross-sectional study analyzed the prevalence and risk factors of pterygia among Han and Tibetan population in Qinghai province. Our results indicated old age, female gender, rural area, outdoor occupation, low education level were associated with a higher prevalence of pterygia, hypertension and hyperopia were associated with pterygia of borderline statistical significance. Compared with Tibetan, Han ethnicity was not a significant risk factor of pterygia. And among males, current smokers had a lower risk. However, risk factors may vary according to genders. We found that risk of pterygia increased among people who lived in rural area more than 10 years, avoiding risk factors in early life may prevent the development of pterygia. |
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