Abstract
Purpose: :
To study the association between cataract and environmental, nutritional and lifestyle factors in older Indians
Methods: :
People aged 60 years and older identified by random cluster-sampling in 2 study centres in north and south India were interviewed for risk factors (tobacco, alcohol, biomass fuel use, sunlight exposure, and socio-economic status) and attended a clinical examination including lens photography, anthropometry and blood sampling. Digital lens images were graded by the Lens Opacities Classification System III (LOCS III). Bloods were analysed for antioxidants, cholesterol and glucose. Logistic regression (Odds Ratios, OR) and 95 % Confidence Intervals, 95% CI, with robust standard errors were done
Results: :
2718 people (76% response rate) in north India and 2973 (76%) in south India completed the protocol. Cataract, defined as LOCS III ≥4 nuclear opalescence, ≥3 cortical and ≥2 posterior subcapsular or dense opacities or already operated, was found in 73%. Significant associations with cataract in age and sex adjusted analyses were found for tobacco chewing (OR=1.7, p<0.0001), smoking (OR= 1.4, p<0.0001), alcohol (OR=1.3, p=0.01), biomass fuel use (OR=2.8, p<0.0001) and low socio-economic class (OR=2.1, p<0.0001). Compared to people of normal weight (BMI 18.5-<25.0) high ORs were found for underweight (OR= 1.6, p <0.0001) and low ORs for overweight/ obese people (OR= 0.7, p <0.001)). Cataract was inversely associated with quartiles of vitamin C (p <0.0001), lutein (p <0.0001), zeaxanthin (p <0.0001) and -tocopherol cholesterol ratio (p <0.01). There was significant association with diabetes in north India (OR= 3.6, p=0.001), and adult lifetime spent outdoors in south India (OR= 1.8, p=0.001). In multivariate models significant associations remained for tobacco chewing, OR= 1.3 (95% CI 1.1-1.5), but not smoking, biomass fuel use, OR=1.6 (1.0-2.5), low socio-economic status, OR=1.8 (1.4-2.2), underweight (OR=1.4, 1.2-1.6), overweight/ obese (OR=0.7, 0.6-0.9). and diabetes (north)(OR=3.2, 1.4-7.3). Inverse associations remained for blood antioxidants except -tocopherol.
Conclusions: :
Indices of poor nutrition and low socio-economic status were most strongly associated with cataract.
Keywords: cataract • clinical (human) or epidemiologic studies: risk factor assessment • nutritional factors