New research presented at this year's European Congress on Obesity (ECO) in Porto, Portugal (17-20 May) shows that rates of weight gain are established by the time women are 18-23 years old. Measuring rates of weight gain at this age could identify women who are likely to become overweight or obese by the time they are 40. Furthermore, women who are divorced, separated or widowed, and those who smoke >10/day are most at risk of becoming overweight or obese. The study is by Professor Wendy Brown, School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, QLD, Australia, and colleagues.
Progression from healthy weight to overweight or obesity is associated with numerous health problems in young adult women. The aims of this study were to track body mass index (BMI) over 16 years in women who had a healthy BMI in the year 2000, to calculate rates of weight change associated with maintenance and/or change in BMI, and to examine the determinants of these changes, in women who were 18-23 years old in 2000.
The study included 4881 women with healthy BMI at baseline, who subsequently remained a healthy weight, or became overweight or obese at 16-year follow-up. These 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.
The data also showed women who were separated (separation, divorce or widowhood) 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 conclude: "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."