Risk factors for endometrial cancer in Japanese women

Abstract

Hachisuga T, Kaetsu A, Sugimori H, Kamura T, Tsuneyoshi M, Kawarabayashi T. Risk factors for endometrial cancer in Japanese women. Int J Gynecol Cancer 1998; 8: 292–297. To elucidate the background for the development of endometrial carcinoma in Japanese females, we studied the risk factors for this disease in a hospital-based, case-control study conducted in the North Kyushu district of Japan from 1980 to 1989 in 242 female subjects with endometrial cancer and 1,021 controls. Furthermore, the association between the risk factors and the clinicopathologic features of endometrial cancer was also examined. In age-adjusted analyses, the risk of endometrial cancer was significantly elevated among gravidity [odds ratios (OR) = 5.00, 95% confidence interval (CI) = 3.09–8.11], nulliparity (OR = 4.01, 95% CI = 2.76–5.83), overweight [body mass index (BMI) of 24.5 to 30.5 OR = 1.85, 95% CI = 1.36–2.25], obesity (BMI <30.5, OR = 2.63, 95% CI = 1.14–6.04), hypertension (OR = 1.63, 95% CI = 1.10–2.43), and diabetes mellitus (OR = 3.03, 95% CI = 1. 74–5.29). This study showed that Japanese females have the same risk factors for endometrial cancer as those reported in Western countries. Further adjustment for parity had little impact on the BMI, hypertension, and diabetes mellitus. A multivariate analysis showed a strong positive association between nulliparity and endometrial cancer risk. Nulliparity is thus a major independent risk factor of endometrial cancer in Japan. Diabetes mellitus was also found to be a strong risk factor for endometrial cancer in this study. It is known that females with polycystic ovary syndrome (PCOS) are associated with increased risk of non-insulin-dependent diabetes, but we could not find non-insulin-dependent diabetes mellitus in 17 patients with endometrial cancer and PCO. A clinicopathologic examination revealed that women in the younger age group (less than 50 years of age) tended to have lower grade tumors, which were more frequently associated with hyperplasia and had a better prognosis than did those in the older age group (50 years of age or older). This may suggest that the tumors developing in the younger age group were more closely related to estrogen than those developing in the older age group, but risk factors that were found to be associated with a high endogenous level of estrogen did not show any meaningful difference between the younger and older age groups.