[Cataract risk factor survey in Funing county of Jiangsu province]

To investigate the risk factors of cataract among people aged 50 years and above in Funing county of Jiangsu province.

Case-control study. All of 1 488 cataract cases were selected from cataract patients' database and 1 821 subjects without visual impairment were recruited as controls from Funing county who were examined between June 2010 and May 2011. Unconditional logistic regression was used to analyze possible risk factors of cataract such as socioeconomic status, lifestyles, history of chronic disease, and history of exposure to sunlight.

The univariate analysis results showed that the risk of cataract on-set was higher with aging. Odds ratios (ORs) for people aged 60 to <70 years, 70 to <80 years, and ≥ 80 years were 6.88, 87.66, and 416.19 respectively with statistical significance comparing to people aged 60 years and below. Female had 12% higher risk of getting cataract than male (OR = 1.24, P = 0.003). Compared with the illiterate, the ORs with educational background of elementary school, junior high school, and high school and above were 0.44 (P < 0.01), 0.42 (P < 0.01) and 0.09(P < 0.01) respectively. The risk of cataract in farmers, smokers, people with high blood pressure or diabetes were significantly high with OR of 3.13 (P < 0.01), 1.23(P = 0.003), 1.44 and 1.92(P < 0.01), respectively. Long time exposure to sunlight increased cataract risk. The ORs of sunlight exposure during 3 to <4 hours, 4 to <6 hours and ≥ 6 hours were 2.09 (P < 0.01), 2.89 (P < 0.01), and 6.52 (P < 0.01) respectively comparing to exposure less than 3 hours per day. Marital status and alcohol drinking were not associated with cataract (P > 0.05). Multiple logistic regression analysis showed that the risk factors of cataract were the age (comparing the age of 50 to <60 years, the OR values of 60 to <70 years, 70 to <80 years and ≥ 80 years were 6.83, 132.39, 868.68 respectively with P < 0.01), the gender (OR = 2.29 for females, P < 0.01) , sunlight exposure (the OR for 3 to <4 hours exposure, 4 to <6 hours exposure and ≥ 6 hours exposure were 2.88, 5.99 and 13.28 respectively comparing to people with less than 3 hour exposure per day), smoking (OR = 1.87, P = 0.019) and diabetes (OR = 1.31, P = 0.029). Education was a protective factor with OR of 0.64,0.41 and 0.31 (P < 0.01) for elementary school, junior high school and high school respectively.

Senior people, female, low level of education, smoking, history of diabetes and long time exposure to sunlight are risk factors of cataract among elderly people aged 50 years and above in Funing country.