Prevalence of three lifestyle factors among Australian adults from 2004 to 2018: An age-period-cohort analysis

Abstract

Background: It has been reported that current smoking, overweight/obesity and physical inactivity are significant modifiable risk factors of all-cause mortality, cardiovascular disease and cancer. However, the effects of age, period and cohort on the prevalence of the three lifestyle factors among Australian adults are still unclear. Methods: Our study analysed data from 2004 to 2005, 2007 to 2008, 2011 to 2012, 2014 to 2015 and 2017 to 2018 National Health Survey. We employed the age-period-cohort models to analyze the individual effects of age, period and cohort on the prevalence of current smoking, overweight/obesity and physical inactivity among Australian adults. Results: A total of 76 489 adults were included. Age, period and cohort all showed significant independent effects on prevalence of current smoking, overweight/obesity and physical inactivity (P < 0.01) except the cohort effect on physical inactivity in females (P = 0.31). The prevalence of current smoking decreased with age and period, and it first increased with birth cohort and then declined. For overweight/obesity prevalence, it increased with age until early-60s and then dropped. We found a positive period effect on overweight/obesity; however, the prevalence of overweight/obesity experienced several shifts with birth cohort. Physical activity prevalence raised with age, and it has several fluctuations for curves of period and cohort. Conclusion: Age effects showed a distinct pattern for the prevalence of the three lifestyle factors. The prevalence of overweight/obesity continued to rise during the study period. The raised physical inactivity prevalence in recent study cycles is also concerning. Recent birth cohorts may be at increased risk of overweight/obesity and physical inactivity.