Childhood obesity cuts life expectancy in half, study shows

Being severely obese as a young child could cut life expectancy by around half, according to a study. However, losing weight could add years back, the researchers said.

The analysis, presented at the European Obesity Congress in Venice and led by German life sciences consultancy stradoo, used data from 50 existing obesity studies to estimate the impact of childhood obesity on conditions such as type 2 diabetes and hope of life.

The combined research included more than 10 million people in countries around the world, including about 2.7 million people between the ages of two and 29. The researchers used a body mass index (BMI) z-score – which measures how far a young person’s weight deviates from the normal range for their age and sex – to estimate how obese the children were.

The higher the BMI z-score, the more the child weighed. The team found that children who were severely obese at age four – with a BMI z-score of 3.5 – had a life expectancy of 39 years if they did not lose weight.

Children with BMI z-scores of 2.0 had an estimated life expectancy of 65 without weight loss, while children with a score of 2.5 had a life expectancy of 50 years. Figures published by the Office for National Statistics in January showed that life expectancy at birth in the UK between 2020 and 2022 was 78.6 years for men and 82.6 years for women.

Dr Urs Wiedemann, from Stradoo, said: “While it is widely accepted that childhood obesity increases the risk of cardiovascular disease and related conditions such as type 2 diabetes and can reduce life expectancy, the evidence on the size of the impact is patchy .

“A better understanding of the precise magnitude of long-term consequences and the factors that determine them could help inform prevention policies and treatment approaches, as well as improve health and extend life.”

The team found that severely obese four-year-olds were also 27% more likely to develop type 2 diabetes by age 25 and 45% more likely to develop the condition by age for 35 years. In comparison, children with BMI z-scores of two at age four had a 6.5% chance of developing type 2 diabetes by age 25 and a 22% change by age 35.