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 The wide differences in incidence of endometrial cancer (type I-carcinoma) across countries and between urban and rural populations, as well as the changing disease incidence in migrants, indicate that environmental factors have a huge influence on the occurrence of the disease. 1 The etiology of endometrial cancer is unknown, yet it has been shown that malignant transformation, cancer cell proliferation, tumor invasion and tumor progression are enhanced by deficiency in progesterone and its action relative to estrogen in the glandular cells of the endometrium. 2,3 A shift in energy balance (e.g., excessive energy intake relative to energy expenditure) might contribute to an unfavorable sex hormone profile in women. 2,4 Epidemiological studies on the association between energy intake and the risk of endometrial cancer are inconclusive. 5-10 A chronically excessive intake of energy relative to requirements may lead to increased body weight. Although adult obesity has consistently been associated with an increased risk of endometrial cancer, the effect may be age and menopausal status dependent. 11 The energy expended during physical activity may represent between 15 and 50% of total energy expenditure, depending on the amount of physical activity performed and the body mass. 12 Epidemiological studies find that inactivity may be associated with an increased endometrial cancer risk. [13][14][15][16][17][18] However, some studies indicate that the effect may be dependent on type of activity (i.e., during work and recreation). 19,20 We have previously reported on the effect of activity, energy intake and accurately measured body mass on the incidence of breast cancer 21 and similar studies on endometrial cancer are needed. 11 Body mass and endogenous levels of estrogens have been associated with risk independently of each other, 22,23 suggesting that the unopposed estrogen/relative progesterone deficiency hypothesis is insufficient to explain endometrial cancer. It has been hypothesized that insulin, a growth factor known for its mitogenic activity, 24,25 plays a major role in endometrial carcinogenesis. Hypertension and diabetes are markers of insulin resistance/hyperinsulinemia. 26,27 Observations linking blood pressure, glucose metabolism and markers of insulin resistance to endometrial cancer come mostly from retrospective studies, which have provided less conclusive results because of self-reported disease history and anthropometry or an absence of adjustment for body mass. 1 We analyzed data that included repeated assessments of variables from a cohort of 24,460 Norwegian women to elucidate whether energy intake, recreational and occupational activity, blood pressure and serum glucose concentration are associated ...