Since high energy intake, inactivity, hypertension and diabetes are linked to obesity and an unfavorable hormonal profile, we wanted to test whether energy intake, physical activity, blood pressure and serum glucose are related to the risk of endometrial cancer independent of the body mass index (BMI). A cohort of 24,460 women, aged 20-49 years, attended a Norwegian health screening twice during 19741981; they answered questions about diet, physical activity and chronic diseases, and their height, weight, blood pressure and non-fasting serum glucose were measured. By the end of 1996, during 15.7 years of follow-up, 130 cases of endometrial carcinomas were identified. The relative risks (RRs) for endometrial cancer were estimated in proportional hazards models including potentially confounding factors. Obese women (BMI greater than or equal to 30 kg/m(2)) were at 2.6 times increased risk of endometrial cancer compared to normal weight women (BMI < 2S kg/m(2)) (RR = 2.57, 95%CI = 1.61-4.10). Among overweight women (BMI < 25 kg/m(2)), non-fasting serum glucose in the upper quartile vs. in the lower quartile was associated with a 2.4 times increase in risk (RR = 2.41, 95%CI = 1.08-5.37), whereas among obese women, blood pressure above 140190 mmHg vs. below 140/90 mmHg in both surveys was associated with a 33 times increase in risk (RR = 3.47, 95%CI = 1.24-9.70). Especially in women younger than 50 years, high energy intake (5,044-6,401 kJ/ day) conferred higher risk compared to low energy intake (< 4266 kJ/day) (RR = 3.40, 95%CI = 1.52-7.60). Increasing recreational activity tended to be protective. Among obese women with non-sedentary jobs at both screenings, RR declined to 0.18 (95%CI = 0.0-0.62) as the level of sustained occupational activity increased (P-trend = 0.03). Our results suggest that inactivity and high energy intake are major risk factors for endometrial cancer independent of BMI, and that hypertension and relative hyperglycemia are significant markers of risk, especially among the heaviest women. (C) 2003 Wiley-Liss, Inc.
