Children born since the 1980s are two to three times more likely than older generations to be overweight or obese by the age of 10, according to new research published in PLOS Medicine. The study, conducted by researchers from CLOSER, a consortium of UK longitudinal studies, characterized population shifts in body mass index (BMI) using data from more than 56,000 people born in Britain from 1946 to 2001.

The findings will be relevant to policymakers and health care professionals, who predict the obesity epidemic will cost the UK's National Health Service (NHS) £22.9 billion per year by 2020. Dr William Johnson, MRC Human Nutrition Research at the University of Cambridge, and Professor Rebecca Hardy and colleagues at the MRC Unit for Lifelong Health and Ageing and the Institute of Child Health at UCL analyzed longitudinal data from individuals in five birth cohorts. The data revealed that most of the rise in BMI has been a result of increases at the upper end of the BMI distribution. Even so, across the 1946, 1958, and 1970 cohorts, the age at which the median adults entered the overweight range decreased from 41 to 33 to 30 years in males and 48 to 44 to 41 years in females. While childhood obesity is more prevalent among younger generations, the majority of today's children are still a normal weight.

The findings describe the changing pattern of age-related progression of overweight and obesity from early childhood in white populations born in the UK. The results may not be generalizable to other populations, which have distinct genetic predispositions, environmental exposures and access to health care, though studies from diverse settings have suggested similar shifts. The authors state, "[o]ur results demonstrate how younger generations are likely to accumulate greater exposure to overweight or obesity throughout their lives and, thus, increased risk for chronic health conditions such as coronary heart disease and type 2 diabetes mellitus. In the absence of effective intervention, overweight and obesity will have severe public health consequences in decades to come."

Citation: Johnson W, Li L, Kuh D, Hardy R (2015) How Has the Age-Related Process of Overweight or Obesity Development Changed over Time? Co-ordinated Analyses of Individual Participant Data from Five United Kingdom Birth Cohorts. PLoS Med 12(5): e1001828. doi:10.1371/journal.pmed.1001828