Endometrial cancer: Population attributable risks from reproductive, familial and socioeconomic factors

In this study, based on the Swedish Family-Cancer Database, risk factors and their population attributable fractions (PAFs) for endometrial cancer were studied. Over 700 000 women at ages 51–68 years, accumulating 23 million person-years at risk, were entered into Poisson analysis. Overall, reproductive factors (parity and age at last birth) showed a relative risk (RR) of 1.91 and a PAF of 45.51% when the reference group was women with a parity of 3+ and the last childbirth at ages over 34 years. The RR for family history was 2.33 but the PAF was only 2.09%. The RR for socioeconomic factors was a modest 1.12 but the PAF was 6.34%. The combined PAF of these three types of risk factors was 51.84%. Although the present analysis lacked data on some important risk factors for endometrial cancer, the results suggest that a large proportion of the etiology of endometrial cancer can be defined by known epidemiological risk factors.