OBJECTIVES: We examined the synergism of cataract and diabetes in micronutrient and antioxidant statuses versus diabetes mellitus and cataract alone. METHODS: Indian patients with type 2 diabetes mellitus (D; n = 76), those without diabetes and with cataract (NDC; n = 100), those with diabetes and cataract (DC; n = 53), and age- and sex-matched healthy controls (n = 90) 50-70 y were investigated. Plasma oxidative stress as thiobarbituric acid-reactive substances (TBARS) and the status of 11 micronutrients were studied as lens TBARS, opacity, and ratio of soluble to total proteins in patients with cataract with or without diabetes. Lipid profile, fasting glucose, and postprandial glucose were measured for all subjects. RESULTS: A subnormal status of ascorbic acid, beta-carotene, thiamine, and ceruloplasmin was elicited for all four study groups. Plasma TBARS and fasting glucose were significantly higher in the DC group than in the NDC (P < 0.05), D, and control groups. Lens TBARS were comparable between the NDC and DC groups (5.5 and 5.08 nm/g of lens). Chi-square values for lens turbidity within the DC and NDC groups and for the ratio of soluble to total proteins and opacity within the NDC group were significant (P < 0.01). The prevalence of poor riboflavin status was 30-36% in all patients and 15-22.5% in controls. Men in the DC group showed a higher value of glycosylated hemoglobin than did men from the D group. Multivariate analysis of variance indicated significant interactions (P < 0.02) between HS and socioeconomic grades for fasting glucose and high-density lipoprotein levels, riboflavin status, plasma vitamin C, TBARS, and selenium. The DC group was found to be significantly different from the other groups with respect to beta-coefficients of a logistic regression equation for plasma levels of selenium, zinc, iron, thiamine, triacylglycerols, total cholesterol, ceruloplasmin, vitamin A, and superoxide dismutase. CONCLUSION: The combination of diabetes and cataract coupled with gender bias and influence of socioeconomic factors seem to be associated with worsening of micronutrient status, oxidative stress, and lens opacity.