Burden of cancer attributable to physical inactivity in Brazil

ELUF-NETO J. ¹

Purpose: To estimate the number of cancer cases attributable to physical inactivity in Brazil. Methods: We estimated the number of cancer cases attributable to physical inactivity using population attributable fraction (PAF). PAF was estimated using the following equation: PAF=P(RR-1)/P(RR-1)+1 where P is the prevalence of physical inactivity, obtained from the National Health Survey in Brazil (PNS 2013), and RR the relative risk of each cancer site (bladder, breast, colon, endometrial, esophageal, gastric, kidney, lung, ovarian, pancreas, prostate) from published meta-analysis showing evidence of association. An individual was considered physically inactive if s/he did not reach the World Health Organization physical activity guideline (≥150 minutes/week) in the following domains: commuting (to work and habitual activities), occupational, and leisure-time. We collected the number of incident cases estimated from the Brazilian National Cancer Institute for 2014 in order to obtain the absolute number of cases attributable to physical inactivity. Results: In 2013, the prevalence of physical inactivity reached 46% in Brazil (men 39.8% and women 51.5%). In a hypothetical scenario in which the whole Brazilian population were physically active, we estimated the following number of cancer cases that could be avoided: 7.6% of bladder cancer (n=684), 6.7% of breast cancer (n=3,841), 12.7% of colon cancer (n=4,135), 11.4% of endometrial cancer (673), 11.0% of esophageal cancer (n=1,191), 9.2% of gastric cancer (n=1,874), 6.1% of kidney cancer (data not available), 13.2% of lung cancer (n=3,602), 5.8% of ovarian cancer (n=331), 3.5% of pancreas cancer (data not available), and 4.2% of prostate cancer (n=2,886). Conclusion: Physical inactivity has a significant role on the burden of cancer in Brazil. Interventions aimed to reduce physical inactivity are important to cancer prevention strategies in Brazil.
Funding source: Leandro Fórnias Machado de Rezende receives funding for his PhD, grant #2014/25614-4, São Paulo Research Foundation (FAPESP).