Leisure-Time Physical Activity and Cancer Risk Among Older Adults: A Cohort Study

OBJECTIVE: To examine the association between leisure-time physical activity (LTPA) and long-term cancer risk in a nationwide cohort of older adults. PARTICIPANTS AND METHODS: The cohort comprised participants of a national survey conducted between July 2005 and December 2006, constituting a random sample of Israeli community-dwelling adults aged 65 years or older. Based on self-reported LTPA habits, participants were classified as sufficiently active, insufficiently active, or inactive according to published guidelines. Cancer diagnosis was assessed via the Israeli National Cancer Registry through September 2015. Inverse probability weighted hazard ratios for incident cancer, based on propensity score, were estimated for LTPA categories. RESULTS: Analysis included 1542 participants with no history of cancer at baseline (median [25th-75th percentile] age, 73 years [69-78 years]; 826 [53.6%] women). Inactive participants (n=641 [41.6%]) were more likely to be female, of lower socioeconomic status, and with higher body mass index and poorer perceived health compared with their insufficiently active (n=443 [28.7%]) and sufficiently active (n=458 [29.7%]) counterparts. In the propensity score–weighted synthetic sample, the distribution of measured baseline covariates was similar across LTPA categories. Over a median follow-up of 9 years, 254 new cancer cases (16.5%) were diagnosed. Leisure-time physical activity was inversely associated with incident cancer, with adjusted hazard ratios (95% CIs) of 0.66 (0.46-0.93) in insufficiently active and 0.59 (0.42-0.82) in sufficiently active participants compared with inactive individuals (P value for trend = .002). CONCLUSION: Among older adults, engaging in LTPA, even at lower levels than officially recommended, may have a beneficial effect on primary prevention of cancer.