Air pollution, smoking and built environment are associated with an increased risk of childhood obesity

Until now, several studies have addressed the effect of many exposures — environmental pollutants, lifestyle factors, and urban environment factors — on childhood obesity, but they studied each single exposure separately.

Now, the Barcelona Institute for Global Health (ISGlobal) and the University of Southern California have led the first major study to investigate the associations between many pollutants and environmental factors — 77 prenatal and 96 childhood exposures — and the risk of childhood obesity. The sum of every exposure to which an individual is subjected from conception to death is known as the exposome.

The findings show that air pollution, smoking and certain characteristics of the built environment, such as high population density, may play a role in the development of obesity in children.

The new study used data on more than 1,300 children aged 6 to 11 years from birth cohort studies in six European countries, included Spain. The authors used data to determine the children’s overweight and obesity status. Blood and urine samples from the children and their mothers during pregnancy were also analysed.

The results showed that exposure to smoking (both maternal smoking during pregnancy and second-hand smoking during childhood), air pollution (PM_2.5 and PM₁₀ particulate matter and nitrogen dioxide, indoor and outdoor) as well as certain characteristics of the built environment were associated with a higher childhood BMI. Differences in socio-economic status did not explain these findings.