Cancers in Australia in 2010 attributable to insufficient physical activity

Regular physical activity is important for optimal health and significant benefits occur from even modest amounts of physical activity,1 including lower cancer rates.2 There is consistent evidence from a systematic review and meta-analysis of cohort studies that physical activity is associated with a reduced risk of colon cancer.3 Research has also consistently demonstrated links between physical activity and reduced risk of post-menopausal breast cancer4 and endometrial cancer.5 The World Cancer Research Fund (WCRF) has concluded that there is “convincing” or “probable” evidence that insufficient physical activity causes cancers of the colon, post-menopausal breast and endometrium.6 The most recent Australian guidelines for physical activity and sedentary behaviour were released in February 2014.7 They recommend that adults perform at least 150 minutes of moderate intensity physical activity or 75 minutes of vigorous intensity physical activity per week to help improve blood pressure, cholesterol, heart health and muscle and bone strength. This should be increased to 300 minutes of moderate intensity physical activity or 150 minutes of vigorous intensity physical activity per week to reap greater health benefits and help to prevent cancer and unhealthy weight gain.7 The National Guidelines defines 60 minutes of moderate intensity physical activity on most days of the week (assumed 5 days) as a sufficient level to help prevent cancer. We aimed to estimate the fraction and number of cancers of the colon, post-menopausal breast and endometrium arising in the Australian population in 2010 that were attributable to failing to meet this target. We assumed that lower levels of physical activity conferred some benefit, but less than optimum.