Background According to the 2018 Third Expert Report from the World Cancer Research Fund/American Institute for Cancer Research, there is strong evidence that physical activity of all types and intensities protects against colon, endometrial and breast cancers. We aimed to estimate the percentage and number of incident cancer cases diagnosed in Texas in 2015 that were attributable to insufficient physical activity, and we examined for differences across racial/ethnic subgroups to reveal important causes of and potential avenues for reductions to cancer health disparities.

Methods We calculated population attributable fractions for cancers attributable to insufficient physical activity using prevalence data from the Texas Behavioral Risk Factor Surveillance System and relative risk estimates associated with insufficient physical activity from prior studies. Cancer incidence data were gathered from the Texas Cancer Registry.

Results Overall, approximately 2.0% of all new cancers or 2094 excess cancer cases diagnosed in 2015 in Texans aged ≥25 years were attributable to insufficient physical activity, with more cancers in women (3.2%) than in men (0.8%). Of all cancer sites, the highest population attributable fraction for insufficient physical activity was observed for endometrial cancers (21.7% compared with 12.7% for colon cancers, 10.9% for premenopausal breast cancers and 2.0% for postmenopausal breast cancers). Hispanics (2.6%) and non-Hispanic blacks (2.5%) had higher proportions of cancers attributable to insufficient physical activity than non-Hispanic whites (1.8%).

Conclusions Public health programmes should stress physical activity as a means of cancer prevention, especially among minority groups, who may have disproportionately higher percentages of cancers attributable to insufficient physical activity.