| Associations between Arsenic in Drinking Water and Pterygium in Southwestern Taiwan Wei Lin,1 Shu-Li Wang,2,3* Horng-Jiun Wu,4 Kuang-Hsi Chang,2 Peter Yeh,1,5 Chien-Jen Chen,6 and How-Ran Guo1,7* 1Department of Environmental and Occupational Health, National Cheng Kung University, Tainan, Taiwan; 2Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Taiwan; 3Institute of Environmental Medicine, College of Public Health, China Medical University Hospital, Taichung, Taiwan; 4Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; 5Department of Ophthalmology, Pingtung Hospital, Department of Health, Pingtung, Taiwan; 6Genomics Research Center, Academia Sinica, Taipei, Taiwan; 7Department of Occupational and Environmental Medicine, National Cheng Kung University Hospital, Tainan, Taiwan Abstract
Background: Pterygium is a fibrovascular growth of the bulbar conjunctiva and underlying subconjunctival tissue that may cause blindness. The mechanism of pterygium formation is not yet fully understood, but pterygium has some tumorlike features. Objectives: The objective of this study was to evaluate the association between arsenic exposure through drinking water and the occurrence of pterygium in southwestern Taiwan. Methods: We recruited participants > 40 years of age from three villages in the arseniasis-endemic area in southwestern Taiwan (exposure villages) and four neighboring nonendemic villages (comparison villages) . Each participant received an eye examination and a questionnaire interview. Photographs taken of both eyes were later graded by an ophthalmologist to determine pterygium status. Results: We included 223 participants from the exposure villages and 160 from the comparison villages. The prevalence of pterygium was higher in the exposure villages across all age groups in both sexes and increased with cumulative arsenic exposure. We found a significant association between cumulative arsenic exposure and the prevalence of pterygium. After adjusting for age, sex, working under sunlight, and working in sandy environments, we found that cumulative arsenic exposure of 0.1–15.0 mg/L-year and ≥ 15.1 mg/L-year were associated with increased risks of developing pterygium. The adjusted odds ratios were 2.04 [95% confidence interval (CI) , 1.04–3.99] and 2.88 (95% CI, 1.42–5.83) , respectively. Conclusions: Chronic exposure to arsenic in drinking water was related to the occurrence of pterygium, and the association was still observed after adjusting for exposures to sunlight and sandy environments. Key words: arsenic, prevalence, pterygium, ultraviolet radiation, water pollutant. Environ Health Perspect 116:952–955 (2008) . doi:10.1289/ehp.11111 available via http://dx.doi.org/ [Online 9 April 2008]
Address correspondence to H.-R. Guo, Department of Environmental and Occupational Health, National Cheng Kung University, 138 Sheng-Li Rd., Tainan 70428, Taiwan. Telephone: 886 6 235 3535, extension 5802. Fax: 886 6 275 2484. E-mail: hrguo@mail.ncku.edu.tw *These authors contributed equally to this work. This work was supported in part by grants EO-093-PP04 and EO-094-PP11 from the National Health Research Institutes (Taiwan) to S.-L. Wang (co-correspondence) and grant NSC95-2918-I-006-014 to H.-R. Guo from the National Science Council (Taiwan) . The authors declare they have no competing financial interests. Received 30 November 2007 ; accepted 7 April 2008.
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