Epidemiology of risk factors for age-related cataract.

Epidemiologic studies on risk factors for cataract have progressed significantly over the last decade. Age-related cataract is a multifactorial disease, and different risk factors seem to play a role for different cataract types. Cortical and posterior subcapsular cataracts appear to be most closely related to environmental stresses such as ultraviolet exposure, diabetes, and drug ingestion. Nuclear cataracts appear to be associated with smoking. Alcohol use seems to be associated with all cataract types. Consistent evidence also suggests that the prevalence of all cataract types is lower among those with higher education. Most of the current data support a role for antioxidants associated with decreased rates of all cataract types, but further studies are needed. More data are needed to establish the association, if any, of diarrhea, blood pressure, and use of allopurinol and phenothiazines with senile cataracts.