Children who are overweight or obese are more likely to develop asthma compared with children of a healthy weight, according to a study published in the American Journal of Epidemiology.

Researchers from Kaiser Permanente in California examined electronic health records of 623,358 children between the ages of 6 and 19.

The children were divided into four groups based on their measured height and weight.

These were:

  • Normal weight
  • Overweight
  • Moderately obese
  • Extremely obese

All children were monitored over the course of 1 year in order to analyze the prevalence of asthma.

The results of the study revealed that children who were overweight were 1.16 times more likely to develop asthma compared with children who were of a normal weight.

Moderately obese children were 1.23 times more likely to develop the condition, while extremely obese children were 1.37 times more at risk.

Of the children who developed asthma, it was found that moderately obese and extremely obese children were more likely to develop regular and aggressive forms of asthma compared with children of normal weight, resulting in hospital visits and treatment with oral corticosteroids – medication used to reduce inflammation and swelling in the airways.

The research also revealed that the effects of body weight and asthma varied depending on race/ethnicity, age and sex.

Moderately obese girls between the ages of 6 and 10 had a 1.36 times higher risk of asthma than girls of normal weight the same age, while extremely obese girls had a 1.56 times higher risk.

Moderately obese Asian-Pacific Islander children had a 1.41 times higher risk of developing the condition, while extremely obese children of this race were at 1.67 times higher risk.

Mary Helen Black, lead study author, says:

As a result of this research, we know that children who are overweight or obese – particularly young girls and Asian-Pacific Islander children – are more likely to develop asthma.

With this knowledge, we can work to develop programs to prevent asthma in high-risk groups. Physicians might also monitor obese children with asthma more closely, since these children tend to have a more severe type of asthma.”

According to the Centers for Disease Control and Prevention (CDC), there are currently 7.1 million children in the US suffering from asthma.

It is the most common chronic condition amongst children, and accounts for more than 13 million total missed days at school each year.

The researchers say that although other studies have acknowledged a link between childhood obesity and asthma, there have not been many large-scale studies in the US confirming this.

Therefore, the researchers at Kaiser Permanente plan to continue their ongoing work to better understand how body weight and body mass index in childhood can increase asthma risk.