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Child obesity risk increases almost three-fold in five generations

Children born since 1990 are up to three times more likely than older generations to be overweight or obese by age 10, according to a new study.

Researchers from CLOSER, a consortium of leading UK longitudinal studies, looked at the body mass index (BMI) of more than 56,000 people born in the UK from 1946 to 2001. They found that around one in ten children born in 1946 were overweight or obese by age 11, compared to roughly one in four 11-year-olds today. Younger generations are also putting on weight more rapidly.

These findings will concern policymakers and health care professionals, as it is estimated that the obesity ‘epidemic’ will cost the UK’s National Health Service £22.9 billion per year by 2050.

Since 1946, every generation has been heavier than the previous one – and worryingly, it is the most overweight people who are becoming even heavier. For example, the heaviest 2 per cent of people born in 1946 had a BMI of around 20 by the age of 11, compared to 27 for the most obese children born at the turn of the century.

People are also becoming overweight or obese at an increasingly younger age, say the researchers who have published their findings in the American journal, PLOS medicine. Half the men of the 1946 generation were overweight by the time they were 41 years old, compared to age 30 for men born in 1970. Half the women born in 1946 were overweight by age 48, compared to 41 for the 1970 generation.

While childhood obesity is more prevalent among more recent generations, the majority of today’s children are still a normal weight.

No other study has been able to track weight gain across as many generations, or through as much of their lives (from age 2 to 64 for the oldest participants in this study).

Professor Rebecca Hardy of University College London, one of the report’s authors, explained: “The more of their lives people spend overweight or obese, the greater their risk of developing chronic health conditions such as coronary heart disease, type 2 diabetes, high blood pressure and arthritis.

“While other research has shown that losing weight at any point in adulthood can help reduce the risk, this study indicates that the UK needs to target its public health interventions at younger and younger ages in order to stem the spread of the obesity epidemic.”

This research uses data collected by five British birth cohort studies: the MRC National Survey of Health and Development (also known as the 1946 British birth cohort), the National Child Development Study (also known as the 1958 British birth cohort), the 1970 British Cohort Study, the Avon Longitudinal Study of Parents and Children (also known as Children of the 90s), and the Millennium Cohort Study.

Listen to a podcast by Professor Rebecca Hardy discussing the main findings of this paper.

Read the full paper

How has the age-related process of overweight or obesity development changed over time? Coordinated analyses of individual participant data from five United Kingdom birth cohorts, by William Johnson, MRC Human Nutrition Research at Cambridge; Leah Li, UCL Institute of Child Health; and Rebecca Hardy and Diana Kuh, MRC Unit for Lifelong Health and Ageing at UCL, will be published in latest issue in PLOS Medicine.