Physical Activity from Adolescence through Midlife and Associations with Body Mass Index and Endometrial Cancer Risk
Menée à l'aide de données portant sur 67 705 femmes âgées de 50 à 71 ans (durée moyenne de suivi : 12,4 ans), cette étude analyse l'association entre l'activité physique depuis l'adolescence et le risque de cancer de l'endomètre (1 468 cas), en fonction de l'indice de masse corporelle
Résumé en anglais
Physical activity is associated with lower risk for endometrial cancer but the extent to which the association is mediated by body mass index (BMI) in midlife is unclear. This study describes the physical activity-endometrial cancer association and whether BMI mediates this relationship.Participants were 67,705 women in the NIH-AARP cohort (50–71 years), who recalled their physical activity patterns starting at age 15–18 years. We identified five long-term physical activity patterns between adolescence and cohort entry (ie, inactive, maintained-low, maintained-high, increasers, decreasers). We used Cox regression to assess the relationship between these patterns and midlife BMI and endometrial cancer, adjusting for covariates. Mediation analysis was used to estimate the proportion of the physical activity-endometrial cancer association that was mediated by midlife BMI.During an average 12.4 years of follow-up 1,468 endometrial cancers occurred. Compared to long-term inactive women, women who maintained-high or increased activity levels had a 19%–26% lower risk for endometrial cancer (maintained-high activity: hazard ratio [HR] = 0.81, 95% confidence interval [CI] = 0.67, 0.98; increasers: HR = 0.74, 95% CI = 0.61, 0.91). They also had a 50%–77% lower risk for obesity in midlife (eg, maintained-high activity: odds ratio [OR] for a BMI of 30–39.9 kg/m2 = 0.50, 95% CI = 0.46, 0.55; and maintained-high activity, OR for a BMI of ≥ 40 kg/m2 = 0.32, 95% CI = 0.26, 0.39). BMI was a statistically significant mediator accounting for 55.5%–62.7% of the physical activity-endometrial cancer associations observed.Both maintaining physical activity throughout adulthood or adopting activity later in adulthood can play a role in preventing obesity and lowering the risk for endometrial cancer.
