Children born in the United Kingdom (UK) since the 1980s are 2-3 times more likely to be overweight or obese by age 10 than those in previous generations, shows an analysis of birth cohorts since the 1940s.

Reporting in PLOS Medicine, researchers analysed data on 56,632 people with with 273,843 BMI (body mass index) observations from five birth cohorts:

The 1946 Medical Research Council National Survey of Health and Development (ages 2-64);
The 1958 National Child Development Study (7-50);
The 1970 British Cohort Study (10-42);
The 1991 Avon Longitudinal Study of Parents and Children (7-18); and
The 2001 Millennium Cohort Study (3-11).

Results showed that children from the more recently born cohorts had a higher probability of being overweight or obese at younger ages.

In each study the median BMI and the prevalence of overweight and obesity generally increased with age after mid-childhood.

Children born after the 1980s had a 2-3 times greater probability of being overweight or obese than those born before the 1980s.

For example, the probability of boys in the 2001 study being overweight or obese by age 10 was 0.229 (95% confidence interval 0.219 to 0.240), compared with only 0.070 (0.063 to 0.078) in the 1970 study.

The increase was similar in girls: the probability of being overweight or obese by age 10 was 0.288 (0.276 to 0.300) in the 2011 study, compared with 0.117 (0.107 to 0.126) in the 1970 study.

Results show that younger generations are at increased risk for chronic health conditions such as coronary heart disease and type 2 diabetes, said the researchers.