Risk factors among young women with endometrial cancer: A Danish case-control study

Abstract

OBJECTIVE:This study was undertaken to identify and quantify risk factors for endometrial cancer among young women. STUDY DESIGN: This case-control study included all Danish women <50 years old who had endometrial cancer diagnosed during the period 1987 to 1994. A total of 237 case patients and 538 population control subjects matched with the case patients for age and residence were included in the analysis. RESULTS: Women with a family history of endometrial cancer had an odds ratio for endometrial cancer of 2.1 (95% confidence interval, 1.1-3.8)). Completion of 1 term pregnancy implied an odds ratio of 0.6 (95% confidence interval, 0.3-1.1). The risk of endometrial cancer decreased significantly with increasing age at first birth and with the number of induced abortions. Use of oral contraceptives for 1 to 5 years decreased the risk of endometrial cancer (odds ratio, 0.2; 95% confidence interval, 0.1-0.3). The odds ratio for endometrial cancer among women who received hormone replacement therapy for 1 to 5 years was 3.1 (95% confidence interval, 1.4-7.0). Body mass index was not demonstrated to be an independent risk factor in this study. The protective impacts of the different exposures (risk factors) can be expressed as etiologic fractions, which indicate how much each exposure reduces the occurrence of endometrial cancer compared with a situation without the existence of that particular exposure. These fractions were as follows: oral contraceptive use for ≥1 year, -45%; 2 term pregnancies, -88%; age ≥30 y when giving birth for the first time, -38%; and a history of incomplete pregnancy, -16%. Key words: Case-control study, endometrial cancer, etiologic fraction, premenopausal, risk factor Endometrial cancer is a rare disease among premenopausal women. Seven percent of endometrial cancer occurs in women <50 years old. In the same age group about 300 curettage procedures and an equal number of endometrial biopsies are performed for every single diagnosis of endometrial cancer. When the physical complications attendant with these invasive procedures and the socioeconomic consequences of curettage as a screening procedure are considered, the question arises as to whether it is appropriate to carry out this number of intrauterine procedures in fertile women to find so few cases of endometrial malignancy.If young women at an increased risk for development of endometrial cancer could be identified, a selection of women among whom the need to undergo curettage was greater might be realized. Consequently, the number of curettage procedures performed in this age group could be reduced.Several studies have identified risk factors of endometrial cancer among older women, such as overweight status, estrogen replacement therapy, nulliparity, infertility, diabetes mellitus, and hypertension. 1-8 However, these risk factors are not necessarily relevant for endometrial cancer among young women. Only a few studies have focused on risk factors for endometrial cancer among premenopausal women (Table I). To identify and quantif...

Reproductive risk factors for endometrial cancer among Polish women

“…Our investigation also enabled evaluation of effects of shortterm pregnancies, including spontaneous and induced abortions. Although several studies have noted either reduced (Parazzini et al, 1998;Parslov et al, 2000) or increased (Shu et al, 1991;McPherson et al, 1996) risks, we found no substantial relationship with spontaneous abortions, in line with most other investigations (Brinton et al, 1992;Xu et al, 2004;Wernli et al, 2006). Previous studies assessing the effects of induced abortion on endometrial cancer risk have been inconsistent, possibly reflecting small numbers of exposed women.…”

“…This factor has not generally been regarded as a predictor of endometrial cancer risk (Pettersson et al, 1986;Lesko et al, 1991;Brinton et al, 1992;Parazzini et al, 1998;Xu et al, 2004), despite a number of studies that have demonstrated relatively strong associations (Kvale et al, 1988;Parslov et al, 2000;Hinkula et al, 2002;Wernli et al, 2006). Although it is widely accepted that multiparity may reduce endometrial cancer risk through changes in hormonal profiles, including lowered estradiol and increased sex hormone binding globulin levels (Chubak et al, 2004), underlying mechanisms for reduced risks associated with delayed ages at a first birth are less clear.…”

“…Previous studies assessing the effects of induced abortion on endometrial cancer risk have been inconsistent, possibly reflecting small numbers of exposed women. The majority have shown either no effect (Parazzini et al, 1991;Brinton et al, 1992;Wernli et al, 2006) or possibly some reduction in risk (Shu et al, 1991;Parazzini et al, 1998;Parslov et al, 2000). We had considerable power to evaluate effects of induced abortions, given that they have been legal in Poland for many years.…”

“…Inverse associations with later ages at a first birth have been demonstrated in some studies (Kvale et al, 1988;Albrektsen et al, 1995;Parslov et al, 2000;Wernli et al, 2006), although not in all of them (Lesko et al, 1991;Parazzini et al, 1991Parazzini et al, , 1998Shu et al, 1991;Brinton et al, 1992;McPherson et al, 1996;Lambe et al, 1999). More recently, studies have suggested that risk may decrease with later ages at a last birth (Kvale et al, 1988(Kvale et al, , 1991Lesko et al, 1991;Parazzini et al, 1991Parazzini et al, , 1998Lambe et al, 1999).…”

Diabetes mellitus and risk of endometrial cancer: a meta-analysis

“…Studies were excluded if they provided only an effect estimate with no means to calculate a CI or if the estimates were not adjusted for age. We excluded two studies [28,30] with unavailable effect estimates and three studies [29,32,33] that reported only crude data not adjusted for age. In the event of multiple publications from the same population or cohort, we included only data from the most recent report or, if the reports included exactly the same time frame, the publication with the most control for confounders.…”