THE PREVALENCE OF EYE DISEASES AMONG RESIDENTS IN AREAS IN NORTHEAST CHINA WITH HIGH AND ACCEPTABLE DRINKING- WATER FLUORIDE LEVELS

Purpose: To investigate the difference in prevalence of seven common eye diseases in rural residents in Northeast China living in areas with high and acceptable levels of fluoride in the drinking water. Methods: All participants (rural residents aged >= 40 yr) underwent ocular examinations and tests related to the fluoride content of their drinking-water, including the fluoride levels in the blood, urine, and drinking-water, x-ray examination, and bone mineral density. The prevalence of seven common eye diseases were compared between subjects consuming drinking water with a high fluoride level, greater than the Chinese National Standard of <= 1.2 mg/L (exposed group), and those with an acceptable fluoride level of mg/L (control group). Results: 1813 participants (766 in the exposed group and 1047 in the control group) were examined. The fluoride level in the drinking-water was closely associated with cataract (OR 0.543, 95% CI 0.310-0.845), pterygium (OR 1.991, 95% CI 1.931-3.622), and arteriosclerotic retinopathy (OR 2.011, 95% CI 1.121-3.637). Compared to the control group, there was a significant decrease in the exposed group of cataract (14.9% in exposed group, 24.7% in control group) and significant increases in the exposed group of pterygium (7.7% in exposed group, 3.2% in control group) and arteriosclerotic retinopathy (17.6% in exposed group, 6.4% in control group). Conclusion: This survey is the first study which has focused on the relationship between the fluoride level in the drinking-water and the prevalence of eye diseases. It provides epidemiological information that can be used in future in-depth studies.