Furthermore, women who are divorced, separated or widowed, and those who smoke more than 10 cigarettes day are most at risk of becoming overweight or obese.
The study was led by Professor Wendy Brown, from the School of Human Movement and Nutrition Sciences at the University of Queensland, and was presented at this year’s European Congress on Obesity in Porto last week.
It tracked the body mass index (BMI) of 4881 women aged 18-23 over 16 years, to calculate rates of weight change and examine the determinants of these changes.
Six surveys
The women reported weight, height, health and health behaviours in six surveys of the Australian Longitudinal Study on Women’s Health between 1996 and 2012. Associations between sociodemographic and behavioural determinants of BMI maintenance and change were estimated using computer modelling.
The data showed 59.4% remained in the healthy BMI category, 29.0% transitioned to overweight and 11.6% became obese. Mean rates of weight gain were 0.19 kg/year (for those who remained healthy weight), 0.84 kg/year (for those who became overweight) and 1.74 kg/year (for those who became obese).
In adjusted models, women higher education were 50% more likely to remain a healthy weight than those with lower education; those with moderate to-high physical activity were 23-44% more likely respectively to maintain healthy weight than inactive women; and those women who drank up to two standard alcoholic drinks per day were 25% more likely to maintain a healthy weight than those who never or rarely drank.
Divorce impact
The data also showed women who were separated (separation, divorce or widowed) were 23% less likely than those who were single to maintain healthy weight. Those who smoked more than 10 cigarettes per day were 36% less likely to maintain a healthy weight than those who never smoked, and those who used oral contraceptives were 11% less likely to maintain a healthy weight than those that did not.
The authors stated: “Weight gain trajectories appear to be established early in young adulthood and are characterised by distinct and fairly constant rates of weight gain at this life stage. Women with healthy BMI, but with higher than optimal rates of weight gain in their early 20s (more than 200g/year), could be identified by health professionals for assistance with prevention of weight gain, thus helping to stem the progression to overweight and obesity in the population. Women who are separated, divorced or widowed, and smokers, could be a priority target group for early intervention to prevent weight gain.”
The study has been published in the American Journal of Preventive Medicine as an early online publication.