One-in-three Australian adults will be obese by 2025, new modelling predicts
They are also predicting a rise in the prevalence of severe obesity by 2025, with 13% of adults having a BMI of over 35 – up from just 5% in 1995 and 9% in 2014/15.
Women will fare worse, with one in six predicted to be severely obese compared to one in 10 men.
The study, published in the Journal of Obesity, states: “The model input population was derived from a nationally representative survey in 1995, representing over 12m adults. Simulations were run for 30 years. The model was validated retrospectively and then used to predict obesity and severe obesity by 2025 among different aged cohorts and at a whole population level.”
Lead researcher, Associate Professor Alison Hayes from the University’s School of Public Health, says the model is the first to predict weight gain among all Australian adults and to reflect changes in the proportion of overweight, obese and severely obese people over time.
“At a population level, young people gain more weight each year than older people,” she said. But for most of us weight gain tends to be cumulative and so we’re more likely to move into an overweight or obese category later in life. An increase in childhood obesity means Australians are starting out adulthood with a higher BMI and higher levels of obesity than ever before.”
Indeed, the study noted that from 1995 onwards, obesity growth in Australia was greatest among young men and women (25-34 years age group in 1995) and lower among those over 45 in 1995.
“These younger generations were predicted to have much higher levels of obesity by the time they reach middle age compared to older generations. Despite this, very few obesity prevention programmes over the last two decades in Australia or internationally have targeted young adults,” it adds.
Whole population
The World Health Organisation’s targets to maintain 2010 levels of overweight and obese people will not be met in Australia, the modelling shows.
Projections at a whole population level show that healthy weight will decline, overweight will remain steady, but obesity and severe obesity prevalence will continue to increase.
“Adult obesity prevalence was projected to increase from 19% in 1995 to 35% by 2025. Severe obesity (BMI>35), which was only around 5% in 1995, was projected to be 13% by 2025, two to three times the 1995 levels,” states the study.
Researchers now believe the model can be used to guide intervention policy by allowing researchers to pose different scenarios – such as ‘What happens if weight gain in young adults is reduced by 10%?’ or ‘What if we reduce childhood obesity?’ – and see the impact on projections.
“We know an increase in obesity and severe obesity will result in higher rates of chronic disease such as type 2 diabetes, cardiovascular disease and cancer, with an increased strain on the health system and healthcare costs,” Professor Hayes said.
“Any reduction in the incidence of obesity going forward will have beneficial impacts on population health and the healthcare costs, but the model can help establish where our efforts should be prioritised.
“The next phase of our research will examine the evidence for successful prevention or weight loss programmes and use the model to help us work out the most effective – and cost-effective – ways to manage obesity in the future.”
Source: Journal of Obesity
“Modelling obesity trends in Australia: unravelling the past and predicting the future”.
Authors: Alison J Hayes
