Physical activity protects against colon cancer risk
Higher levels of physical activity appear to reduce the risk of developing colon cancer, independent of colonic subsite, according to a study. Conversely, sedentary behaviour is associated with an increased risk.
The study population comprised 430,584 men and women from the UK Biobank. Multivariable Cox proportional hazards models were used to analyse physical activity levels (metabolic equivalents (METs)-hours per week) and sedentary behaviour indicators (television watching time and time spent using computers) in relation to the risk of colorectal cancer.
A total of 2,391 patients developed colon cancer during a median follow-up of 5.6 years. On analysis, higher levels of total physical activity (≥60-MET-hours per week) showed a protective effect on the risk of colon cancer (vs <10-MET-hours per week: hazard ratio, 0.84; 95 percent CI, 0.72–0.98; p=0.04 for trend), with comparable relationships observed for proximal and distal colon tumours.
Physical activity was not associated with rectal cancer.
With respect to sedentary behaviour, higher levels of television watching time showed a positive association with colon cancer risk. Compared with ≤1 hour/day of television watching time, ≥5 hours/day increased the risk of developing colon cancer by 1.32 times (1.04–1.68; p=0.007 for trend). This relationship was not observed for rectal cancer.
Neither colon nor rectal cancer was associated with time spent using computers.
Findings of the present study contribute to the large body of evidence supporting the promotion of physical activity in population-wide cancer prevention programmes, researchers said.