Case-control study of diabetes, obesity, physical activity and risk of endometrial cancer among Mexican women

Objectives: Obesity, hypertension and diabetes are closely associated with endometrial cancer (EC). This study evaluates the relationship between diab etes and risk of EC on the basis of obesity. Methods: A case-control study was carried out in Mexico City from 1995 to 1 997. Eighty-five histologically confirmed cases were compared with 668 popu lation-based controls obtained through frequency matching. Diabetes status, weight, height and other factors were determined through personal intervie ws among both cases and controls. Results: Compared to women without diabetes, those with diabetes had an adj usted odds ratio of 3.6 (95% CI = 1.7, 7.4) for EC. This association was mo dified by body mass index (p interaction < 0.001). Compared to non-overweig ht and non-diabetic women, non-overweight (OR = 3.9, 95% CI = 0.88, 18.0) a nd overweight (OR = 5.9, 95% CI = 1.6, 21.1) diabetic women had a non-signi ficant elevated risk of EC. However, elevated risk estimates were observed for obese diabetic women (OR = 8.0, 95% CI = 2.8, 22.7). Conclusions: Our results strongly suggest an interaction effect between obe sity and diabetes that significantly increases the risk of EC. This, in tur n, may explain the growing number of new EC cases recently observed in deve loping countries with reduced birth rates and an increased incidence of bot h obesity and diabetes mellitus.