High body mass index (BMI >25kg/m2) has been found to be associated with an increased risk of many cancers, including cancers of the colon and rectum, liver, and pancreas. This study aimed to estimate the future burden of cancer resulting from current levels of overweight and obesity in Australia.
The future excess fraction method was used to estimate the future burden of cancer among the proportion of the Australian adult population who were overweight or obese in 2016. Calculations were conducted for 13 cancer types, including cancers of the colon, rectum, kidney, and liver.
The cohort of 18.7 million adult Australians in 2016 will develop approximately 402,500 cancers attributable to high body mass index over their lifetime. The majority of these will be postmenopausal breast cancers (n=72,300), kidney cancers (n=59,200), and colon cancers (n=55,100). More than a quarter of future endometrial cancers (30.3%) and oesophageal adenocarcinomas (35.8%) will be attributable to high body mass index.
A significant proportion of future cancers will result from current levels of high body mass index. Our estimates are not directly comparable to past estimates of the burden from overweight and obesity because they describe different quantities – future cancers in currently exposed versus current cancers due to past exposures. The results of this study provide us with relevant up-to-date information about how many cancers in Australia could be prevented.