Physical Activity and Risk of Endometrial Cancer: A Population-Based Prospective Cohort Study

Abstract

Physical activity is involved in the regulation of metabolic and hormonal pathways and is one of the factors important for the maintenance of body weight; obesity is a risk factor for endometrial cancer. A connection between physical activity and endometrial cancer risk through hormonal mechanisms, possibly mediated by body weight, is biologically plausible. Only one study has investigated total physical activity, and no previous study has examined leisure time inactivity directly. We investigated the association of total physical activity and different types of physical activity with risk of endometrial cancer in the Swedish Mammography Cohort, a population-based prospective cohort, including 33,723 women and 199 endometrial cancer cases. After adjustments for potential confounders (age, body mass index, parity, history of diabetes, total fruit and vegetable intake, and education), the relative risks for endometrial cancer for the second to fourth quartile of total physical activity compared with the lowest one were 0.80 [95% confidence interval (95% CI), 0.54-1.18], 0.87 (95% CI, 0.59-1.28), and 0.79 (95% CI, 0.53-1.17). High leisure time inactivity (watching TV/sitting z5 hours daily) compared with low was associated with increased risk of endometrial cancer (relative risk, 1.66; 95% CI, 1.05-2.61). The associations were not modified by body mass index. Findings from this study suggest that total physical activity is weakly inversely associated with endometrial cancer risk and that leisure time inactivity is statistically significantly associated with increased risk for endometrial cancer. (Cancer Epidemiol Biomarkers Prev 2006;15(11):2136 -40)

Sedentary Behavior and Cancer: A Systematic Review of the Literature and Proposed Biological Mechanisms

“…For the review on sedentary behavior and cancer, 18 relevant articles were identified (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38). For sedentary behavior and adiposity, 76 articles originating from 62 studies were selected for review (10,12,13,(15)(16)(17).…”

“…Statistically significant, positive associations between sedentary behavior and cancer were found in 8 of the 11 studies (21,23,24,26,29,30,33,35). An additional study had a borderline statistically significant, positive association (25), and one observed a nonstatistically significant risk increase (31).…”

“…Six of the 11 cancer risk studies were prospective cohort studies (23,25,26,(29)(30)(31), four were case-control studies (24,28,33,35), and one was a randomized controlled trial (21). The association between sedentary behavior and cancer risk was investigated in four studies of endometrial cancer (23)(24)(25)31): three of colorectal cancer (21,26,33), two of ovarian cancer (30,35), and one each of breast (28) and prostate (29) cancer.…”

A population-based cohort study on sun habits and endometrial cancer

“…Other cohort studies have shown differing results; most have found a decreased risk in physically active women (Furberg and Thune, 2003;Schouten et al, 2004;Friberg et al, 2006), whereas others showed no association (Colbert et al, 2003). Hypothesised mechanisms include changes in obesity and/or fat mass as well as a reduced exposure to endogenous oestrogens (McTiernan et al, 1998).…”

Associations between sitting time and a range of symptoms in mid-age women

“…To date, sedentary behaviour epidemiology has mainly focused on outcomes related to cardiovascular and metabolic health. Measures of sedentary behaviour have however, also been related to gallbladder disease (Leitzmann et al, 1998;Leitzmann et al, 1999), cancer (Friberg et al, 2006;Gierach et al, 2009;Patel et al, 2008;Patel et al, 2006), and mental disorders (Sanchez-Villegas et al, 2008). These relationships with conditions that involve various body systems, suggest a wide-ranging impact of sedentary behaviour on health.…”