Effectiveness of sustained leisure-time physical activity strategies for obesity-related cancer prevention: an emulated target trial in a prospective US cohort
Mené à partir de données portant sur 60 958 personnes n'ayant pas de cancer (durée médiane de suivi : 11,4 ans), cet essai in silico évalue l'effet d'une activité physique de loisir d'intensité modérée à soutenue sur le risque de cancer lié à l'obésité, en fonction du respect des recommandations
Background: Obesity-related cancers account for 40% of US cancer cases, and their global burden continues to rise. Cancer prevention guidelines recommend 150–300 min of moderate or 75–150 min of vigorous-intensity activity per week (7.5–15 MET-hrs/wk). However, the long-term causal effect of sustained leisure-time moderate-to-vigorous intensity physical activity (MVPA) on obesity-related cancer risk has not been quantified.
Methods: We emulated a target trial using data from 60,958 cancer-free adults in the Cancer Prevention Study-II Nutrition Cohort (2001–2013) to estimate 11-year risks of obesity-related cancers under four sustained MVPA strategies: (1) no intervention (observed MVPA); (2) below recommendations (> 0– < 7.5 MET-hrs/wk); (3) meeting recommendations (7.5–15 MET-hrs/wk); and (4) exceeding recommendations (> 15 MET-hrs/wk). MVPA was self-reported every 2 years. The parametric g-formula was used to estimate cancer risk under each strategy among all eligible participants and stratified by pre-intervention MVPA (meeting vs. not meeting recommendations 2 years prior to intervention).
Results: Over a median follow-up of 11.4 years (IQR 6.9–11.8), 4344 obesity-related cancers were diagnosed. Under no intervention, median baseline MVPA was 12.8 MET-hrs/wk (IQR 4.5–24.5) overall, 20.5 (IQR 15.2–30.8) among those meeting (n = 38,558), and 4.3 (IQR 1.5–6.2) among those not meeting recommendations pre-intervention (n = 22,400). The estimated 11-year cancer risk under no intervention was 8.2% overall, 8.1% among those meeting, and 8.7% among those not meeting recommendations pre-intervention. Compared to no intervention, risk differences were 0.18% (95% CI: 0.05% to 0.37%) for below-recommendation MVPA, 0.08% (95% CI: − 0.05% to 0.19%) for meeting, and − 0.18% (95% CI: − 0.44% to 0.01%) for exceeding recommendations. Among those meeting recommendations pre-intervention, risk differences were 0.34% (95% CI: 0.11% to 0.65%), 0.09% (95% CI: − 0.06% to 0.26%), and − 0.21% (95% CI: − 0.45% to − 0.05%), respectively. Among those not meeting recommendations, corresponding risk differences were − 0.02% (95% CI: − 0.31% to 0.27%), − 0.04% (95% CI: − 0.21% to 0.15%), and − 0.10% (95% CI: − 0.38% to 0.14%).
Conclusions: We estimated that, compared to no intervention, sustaining MVPA volumes below recommendations may modestly increase obesity-related cancer risk over 11 years, whereas exceeding recommendations may modestly reduce risk, particularly among participants already meeting the recommendations prior to intervention.
BMC Medicine , article en libre accès, 2025