Obesity and Endometrial Cancer: Challenges for Public Health Action

“Approximately 60% of endometrial cancer incidence is attributable to obesity, and obese women diagnosed with endometrial cancer have six-times the risk of dying of nonobese women.”

Obesity is a major public health concern. Obesity and weight gain increase risk for many chronic diseases, including coronary disease, stroke, Type 2 diabetes, as well as several types of cancer [1]. The prevalence of obesity doubled in US adults during the period from 1980 to 2002, and while rates may be leveling off in women, the most recent data available indicate that the prevalence of obesity continues to increase in men, children and adolescents [2,101,102]. In a detailed analysis of preventable causes of death in the USA, Danaei et al. estimated that overweight/obesity and physical inactivity together were responsible for nearly 20% of all deaths [3]. The WHO estimates that approximately 1.5 billion adults were overweight globally, and that by 2015, approximately 2.3 billion adults will be overweight, with dramatic increases in low- and middle-income countries [103].

“…obesity and weight gain in adulthood are risk factors for endometrial cancer.”

In the USA, endometrial cancer is the fourth leading cancer diagnosed in women after breast, lung and colorectal cancer, and is one of the top ten leading causes of cancer deaths [4]. In the USA, the incidence trends have been declining for white women, but a concomitant decrease has not been observed for black women [5]. More specifically, for women younger than 50 years of age, incidence rates for white women have remained level and increased significantly for black women since the mid-1980s [5].

Endometrial cancer is linked with lifestyle factors, including lack of physical activity, poor dietary choices [6], obesity [2,7] and weight gain over the lifespan [8]. Several studies have reported increased risk of developing endometrial cancer with increasing body weight or body mass index (BMI) [7,9], which is an index of weight status that accounts for height and is calculated by dividing weight in kilograms by height in meters squared. For adults, a BMI of 25.0–29.9 is defined as overweight, and a BMI of 30.0 or higher is defined as obese [104]. Based on a comprehensive review of the literature, the World Cancer Research Fund recently concluded that ‘body fatness and probably abdominal fatness are causes of endometrial cancer, and physical activity is protective’ [10]. This finding is consistent with an earlier report from the International Agency for Research on cancer (IARC) that concluded that obesity and weight gain in adulthood are risk factors for endometrial cancer [11].

In this article, we briefly review evidence linking obesity and endometrial cancer and discuss some potential mechanisms, then describe public health approaches to obesity prevention and control that may decrease risk for developing this cancer, particularly for younger women.

Effects of overweight & obesity

The development of endometrial cancer through obesity is felt to be mediated by several mechanisms, including development of hyperinsulinemia and/or Type 2 diabetes, and increased sex hormone production from adipose tissue leading to unopposed estrogen stimulation of the endometrium for postmenopausal women [9,12]. As the population ages, we anticipate that endometrial cancer will continue to be a public health and medical problem in the USA and worldwide. In addition, the incidence of endometrial cancer has increased among younger women in the USA. This increase parallels the trends in increasing overweight and obesity in this country. We may see an increase worldwide as more countries transition from developing to developed, and the prevalence of overweight and obesity continue to increase. The human and financial costs of obesity are significant [13]. Approximately 60% of endometrial cancer incidence is attributable to obesity [12], and obese women diagnosed with endometrial cancer have six-times the risk of dying of nonobese women [14].

Possible interventions

Considering the associations between overweight and obesity with endometrial cancer, interventions to stabilize or decrease the prevalence of obesity and its downstream effects, including endometrial cancer, are needed. Weight maintenance, healthy food choices and appropriate levels of physical activity are documented to be associated with a lower risk of developing endometrial cancer by multiple organizations, including the IARC, and the American Cancer Society [11,15].

The Centers for Disease Control and Prevention recently released recommendations to guide communities in how they might change nutrition and physical activity environments to prevent increases in obesity [16]. At the community level, environmental and policy changes that support choices about diet and physical activity, such as increasing access to healthy food choices or places for people to be physically active, should be implemented as well. Finally, efforts to raise public awareness of the connection between obesity and risk of developing endometrial cancer and other chronic diseases must be more intentional among public health practitioners and healthcare providers and women. A recent study reported that up to 50% of women were unaware of the association between being overweight or gaining weight and endometrial cancer [17]. Even though the association between obesity and cancer is clear, the public is not aware of the elevated risk [7,17].

Public health implications

With the rapid increase in weight gain and obesity noted worldwide, endometrial cancer is sure to increase. Overweight and obesity cannot be managed only at the individual level. Community level policy changes and interventions are needed to complement individual efforts. Work is also needed to increase awareness among women of the excess risk associated with obesity for developing endometrial cancer. At a community level, success will likely be achieved with efforts across multiple sectors in society [18]. Action must be taken by governments, industries, communities at large, worksites, schools and in the home [18,20]. Policy changes to provide access to healthier food choices [21] and community level interventions to change the built environment can help in combating the obesity epidemic and its downstream effects, including cancer.

“Overweight and obesity cannot be managed only at the individual level. Community level policy changes and interventions are needed to complement individual efforts.”

Similar to the tobacco cessation efforts where short-term benefits were noted with lung and heart conditions and longer-term benefits with cancer rates lagging behind [22,23], the same may be true for obesity prevention efforts. Efforts to address the obesity epidemic will require increasing awareness of the problem and its connection to chronic illness, changing attitudes regarding healthy nutrition and increased physical activity, helping individuals change their behaviors, and introducing policy and environment supports for behavior change.