Background and significance
Knowledge of obesity and overweight as a cancer risk factor remains at a moderate level in comparison to well known risk factors such as tobacco and sun damage; however, the extent to which knowledge of obesity and overweight as a cancer risk factor is associated with behavioural outcomes has not been commonly assessed or tracked over time.
This study tracked community awareness of obesity-related risk factors for cancer and level of overweight and obesity from 2004-2012. Data from five South Australian cross-sectional representative population surveys with approximate sample sizes of n=3,000 were analysed (adjusted for age, gender and socio-economic disadvantage) at 2-year intervals from 2004-2012.
While levels of unprompted awareness of maintaining a healthy weight as a cancer prevention strategy increased significantly over time (from 2004, 2006 and 2008 to 2012; OR=0.32-0.72, p<0.01), perceptions of being overweight as an important risk factor for cancer decreased significantly (from 2006, 2008 and 2010 to 2012; OR=1.32-1.76, p<0.001). Rates of overweight and obesity increased significantly from 2004 to 2012 (54% vs. 60%; p<0.001). A significant association between unprompted awareness of maintaining a healthy weight and level of overweight/obesity was found only in 2010 such that those who were in the overweight and obese range were more knowledgeable (OR=0.53, p<0.01). Conversely, a significant association was observed between prompted awareness of being overweight as an important risk factor for cancer and behaviour in 2010 (OR=0.85, p<0.05) and 2012 (OR=0.82; p<0.05) such that those in the overweight and obese range were less inclined to perceive overweight and obesity an important risk factor for cancer.
While the results indicate some degree of convergence between knowledge and behaviour in recent years, patterns differed according to assessment, i.e., unprompted awareness of maintaining a healthy weight vs. perceived relative importance of being overweight.