The relationship between cataract extraction in women and current body mass index, history of clinically relevant obesity, diabetes, hypertension, and hyperlipidemia was considered in a case-control study conducted in northern Italy. A total of 287 women who had cataract extraction and 1227 control subjects who were in the hospital for acute, nonneoplastic, nonophthalmologic, nonmetabolic, nongastroenterologic diseases were interviewed during their hospital stay. Odds ratios (ORs) and their 95% confidence intervals (CIs) were derived from multiple logistic regression equations, including terms for age, education, smoking status, current body mass index, and simultaneously the four diseases considered. Elevated current body mass index (OR, 2.2; 95% CI, 1.2 to 3.8, for > or = 30 versus < 20 kg/m2), diabetes (OR, 2.2; 95% CI, 1.4 to 3.4), hypertension (OR, 1.5; 95% CI, 1.1 to 2.0), hyperlipidemia (OR, 1.8; 95% CI, 1.2 to 2.7), and clinical history of obesity (OR, 1.5; 95% CI, 1.0 to 2.2) were associated with an increased risk of cataract extraction. The OR in two separate strata of age (< 60 and > or = 60 years) indicated that the associations of diabetes and hyperlipidemia were stronger at a younger age: the OR for diabetes was 4.6 for those younger than 60 years and 1.7 for those age 60 or over, and for hyperlipidemia the ORs were 2.8 and 1.6, respectively. Thus, the results of this study support the association in women between cataract extraction and diabetes, current overweight, history of clinically relevant obesity, hypertension, and hyperlipidemia. These findings also suggest that these factors may have some biologically independent impact on the risk of cataract.