Impact of overweight, obesity and severe obesity on life expectancy of Australian adults

Obesity is known to significantly elevate the risk of many health problems, however its impact on life expectancy (LE) has not been quantified in Australia. This paper, published in the International Journal of Obesity, uses a microsimulation model of obesity progression to predict the changes in LE and years of life lost (YLL). It uses data on annual change in BMI based on age and sex, with Australian life-table data and published relative risk of all cause-mortality for different BMI categories. A nationally representative sample of 12,091 adults aged 20-69 were used.

The study predicted that the loss in LE for obese people to be 5.6-7.6 years and for severely obese people to be 8.1-10.3 years for men and women aged 20-29 years. If the baseline BMI was higher, so at age 20-29 BMI was above 25, years lost was greater. It also found that men lost 27.7% more years compared to women. In total, overweight and obesity was predicted to be responsible for 36.3 million YLL over the life course, with the severely obese contributing almost one-third of the life years lost despite comprising only 11% of the population.

This study does not take into account the impact that increased BMI has on quality-of-life, however evidence has shown there are significant impairments to health related quality-of-life for individuals at more severe levels of obesity as a result of co-morbidity and disability. This paper highlights the huge burden of disease in Australia, particularly in men, that needs to be addressed. The implication on the economy and the individual of 36.3 million YLL are too huge to ignore.