Proportion of Cancer Cases Attributable to Physical Inactivity by US State, 2013-2016

Little is known concerning the cancer burden attributable to physical inactivity by state. Our objective was to calculate the proportion of incident cancer cases attributable to physical inactivity among adults age ≥30 yr in 2013-2016 in all 50 states and District of Columbia.

State-level, self-reported physical activity data from the Behavioral Risk Factor Surveillance System were adjusted by sex, age, and race/ethnicity using national-level, self-reported physical activity data from the National Health and Nutrition Examination Survey. Age-, sex-, and state-specific cancer incidence data were obtained from the US Cancer Statistics database. Sex-, age-, and state-specific adjusted prevalence estimates for eight physical activity categories and cancer-specific relative risks for the same categories from a large-scale pooled analysis were used to calculate population-attributable fractions (PAF) by state for stomach, kidney, esophageal (adenocarcinoma), colon, bladder, breast, and endometrial cancers.

When optimal physical activity was defined ≥5 h·wk-1 of moderate-intensity activity, equivalent to ≥15 MET·h·wk-1, 3.0% (95% confidence interval (CI), 2.9%-3.0%) of all incident cancer cases (excluding nonmelanoma skin cancers) were attributable to physical inactivity, accounting for an average of 46,356 attributable cases per year. The PAF ranged from 2.3% (95% CI, 2.2%-2.5%) in Utah to 3.7% (95% CI, 3.4%-3.9%) in Kentucky. By cancer site, the PAF ranged from 3.9% (95% CI, 3.6%-4.2%) for urinary bladder to 16.9% (95% CI, 16.1%-17.7%) for stomach.

Our results indicate that promoting physical activity through broad implementation of interventions could prevent many cancer cases. Over 46,000 cancer cases annually could be potentially avoided if the American population met the recommended 5 h·wk-1 of moderate-intensity (or 15 (MET)-h·wk-1) physical activity.