Measuring the potential impact of physical inactivity on worldwide epidemiology of colorectal and breast cancers

Abstract

Background: Solid evidence has been published in support of a strong association between physical inactivity and enhanced risk of colorectal and breast cancers. This article aims to objectively assess the worldwide epidemiology of physical inactivity-related burden of colorectal and breast cancers. Methods: An electronic search was performed in the Global Health Data Exchange (GHDx) registry, a large database of health-related data, using the keywords “low physical activity” in the category “risk”, combined with “colon and rectum cancer” AND “breast cancer” in the category “cause”. The output of the electronic search was downloaded in comma-separated values (CSV), imported into an Excel file and analyzed. Results: The contribution of physical inactivity on the current burden of disability-adjusted life years (DALYs) and mortality is estimated at 3.44% and 3.64% for colorectal cancer, and at 1.43% and 1.54% for breast cancer, respectively. The impact of physical inactivity on the epidemiologic burden of colorectal cancer is constantly higher in women than in men, whilst it also increases in parallel with the socio-demographic index (SDI) in both types of cancer. The effect of physical inactivity on DALYs and deaths caused by these two malignancies remains substantially stable up to the age of 50 years, but then linearly increases, peaking in the elderly. In multivariable analysis, physical inactivity-related DALYs and deaths for colorectal cancer were independently associated with female sex, older age and higher SDI. Physical inactivity-related DALYs and deaths for breast cancer were also independently predicted by older age and higher SDI. Conclusions: The contribution of physical inactivity to the current burden of colorectal and breast cancer seems higher in the elderly, in people living in middle-to-high SDI countries, and in the female sex as regards colorectal cancer.