Early Socioeconomic Factors Have Major Impact on Asthma Risk, Study Finds

The data suggest early factors in the home are the most important links to asthma risk in children.

A new analysis of socioeconomic status and pediatric asthma found that perinatal factors and early home life environment are more important predictors of persistent asthma than environmental factors outside of the home.

The study was published in the journal Thorax.

Corresponding author Hanna Creese, PhD, MSc, of Imperial College London and colleagues, noted it has already been established that children who are economically disadvantaged have higher rates of asthma, although it is not clear what impact early environmental factors might have on rates and severity of the disease. Overall, about 8% of children between the ages of 12 and 17 in the United Kingdom receive treatment for asthma, they said.

Creese and colleagues hypothesized that the circumstances of a child’s early years might be an important piece of the asthma puzzle. Specifically, they suspected that the specifics of patients’ family lives and homes might be more important than factors they might encounter outside of the home, such as neighborhood characteristics.

To test their theory, they used the Millennium Cohort Study, a prospective study of nearly 19,000 British children born between the years 2000 and 2002. Data sweeps of the cohort were conducted at various intervals of the children’s lives, including at ages 7, 11, and 14. Creese and colleagues based their analysis on children who were singletons, had complete data, and were still participating in the study at age 14. That left a sample of 7487 patients.

Patients were divided based on 3 asthma-related categories: those who had never had an asthma diagnosis, those who had a transient asthma diagnosis (reported at one of the 3 time intervals, but not the other 2), and those who had persistent asthma (diagnoses reported at at least 2 of the 3 time points).

The authors then compared asthma rates to maternal education data as a means of understanding the child’s socioeconomic circumstances. They then looked at how perinatal risk factors and environmental risk factors mediated the effect of socioeconomic circumstances.

The investigators found an overall rate of persistent asthma of 15% among 14-year-olds, but they also found the risk varied significantly based on the factors assessed. For instance, among the most economically disadvantaged children, the persistent asthma rate was 20%. Among the most advantaged, it was 13%.

“Being born into disadvantaged [socioeconomic circumstances] increased the likelihood of developing persistent asthma by 70%,” Creese and colleagues found. “Almost two-thirds (58.9%) of the excess risk [was] attributable to perinatal and environmental exposures by the age of 3 years.”

No similar effect was found among children with transient asthma.

Creese and colleagues said the data have a number of policy implications.

“Our results support the need for an early prevention strategy to focus on ensuring optimal conditions during pregnancy and childhood to support the healthy development of children and reduce inequalities across the lifecourse,” the authors wrote.

While current policy in the UK is based in part on these goals, investigators said guidelines are more focused on individual action than on addressing societal or systematic factors.

On a patient level, the authors said physicians should consider a mother and child’s socioeconomic circumstances and more closely monitor children who are at higher risk of persistent asthma.

The authors said physicians and public health officials should work to discourage smoking among pregnant women and encourage breastfeeding among new mothers. They also said government action to improve housing conditions in low-income areas will be important.

Reference:

Creese H, Lai E, Mason K, et al. Disadvantage in early-life and persistent asthma in adolescents: a UK cohort study. Thorax. Published online October 14, 2021. doi:10.1136/thoraxjnl-2021-217312