Changes in Physical Activity and Cardiovascular Disease Risk in Cancer Survivors: A Nationwide Cohort Study

Cancer survivors face an elevated risk of cardiovascular disease, with physical inactivity after cancer treatment potentially worsening this risk.

The aim of this study was to investigate the association between physical activity before and after a cancer diagnosis and the risk for heart disease.

A nationwide cohort of 269,943 cancer survivors (mean age 56.3, 45.7% men) was evaluated for physical activity adherence 2 years before and after diagnosis. The primary outcomes were the incidence of myocardial infarction (MI), heart failure (HF), and atrial fibrillation. Subdistribution HRs (sHRs) and 95% CIs were calculated using Gray's method, accounting for death as a competing risk.

Over a follow-up period of 1,111,329.28 person-years, compared with those who remained inactive, persistent physical activity was associated with a 20% reduction in MI risk (sHR: 0.80; 95% CI: 0.70-0.91) and a 16% reduction risk in HF risk (sHR: 0.84; 95% CI: 0.78-0.90). Initiating physical activity after a cancer diagnosis was linked to an 11% lower risk for MI (sHR: 0.89; 95% CI: 0.79-0.99) and a 13% lower risk for HF (sHR: 0.87; 95% CI: 0.82-0.93). Being active only before diagnosis was associated with a 20% lower risk for MI (sHR: 0.80; 95% CI: 0.71-0.91) and a 6% lower risk for HF (sHR: 0.94; 95% CI: 0.88-1.00). No association was observed between physical activity and atrial fibrillation risk. Associations varied by primary cancer site.

These findings underscore the importance of maintaining physical activity for cardiovascular health in cancer survivors and suggest that physical activity before a diagnosis may offer enduring protection against ischemic heart disease and cardiac dysfunction.