Physical activity and risk of bladder cancer among postmenopausal women
Menée aux Etats-Unis à l'aide de données 1993-1998 portant sur 141 288 femmes ménopausées (âge moyen : 63,3 ans ; durée moyenne de suivi : 18,5 ans), cette étude analyse l'association entre la pratique d'une activité physique d'intensité modérée à vigoureuse et le risque de cancer de la vessie (817 cas)
Physical activity is associated with decreased risk for many cancers. Studies on the association between physical activity and risk of bladder cancer are limited, and findings are inconsistent. Postmenopausal women (mean age= 63.3) were recruited into the Women's Health Initiative from 1993 to 1998. Self-reported baseline information on physical activity and other covariates were available in 141,288 participants. Incident bladder cancer cases were collected through 2018 and centrally adjudicated. Hazard ratios (HRs) and 95% confidence intervals (CIs) were determined by Cox proportional hazard regression models. Effect modification due to smoking was assessed. During an average of 18.5 years of follow-up, 817 bladder cancer cases were identified. Compared with physically inactive women, those who engaged in ≥15 MET-hours/week of total physical activity, ≥8.75 MET-hours/week of walking or ≥11.25 MET-hours/week of moderate to vigorous physical activity had lower risk of bladder cancer (HR = 0.74, 95% CI: 0.59-0.94, P for linear trend = 0.02; HR = 0.79, 95% CI: 0.63-0.98, P for linear trend = 0.03; and HR = 0.76, 95% CI: 0.61-0.94, P for linear trend = 0.02, respectively). No effect modification was found by smoking status (P for interaction = 0.06, 0.91 and 0.27, respectively). We found that total physical activity, walking and moderate to vigorous physical activity were inversely associated with bladder cancer incidence among postmenopausal women in a dose-response manner. Physical activity may play a potential role in the primary prevention of bladder cancer. Further studies with objective measurements of physical activity are needed to confirm these findings.