Sociodemographic factors, current asthma and lung function in an urban child population.

Background: We aimed to assess which sociodemographic factors are associated with current asthma and indicators of lung function in 10-year-old children.

Methods: We analysed data of 5237 children (Mean age: 9.7, SD: 0.3) from the Generation R Study (2012-2016), a population-based cohort study in the Netherlands. Indicators of sociodemographic factors included parental educational level, net household income, financial difficulties, parental employment status and child ethnic background. Current asthma (yes/no) was defined as ever doctor-diagnosed-asthma combined with wheezing symptoms or asthma-medication use in the past 12 months. Lung function was measured by spirometry and included forced expiratory volume in 1 second (FEV ), forced vital capacity (FVC), FEV /FVC, and forced expiratory flow after exhaling 75% of FVC (FEF ). Within-study sex-, height- and age-adjusted lung function measurements' z-scores were converted.

Results: After adjustment for all sociodemographic factors, an independent association was observed between ethnic background with current asthma and lung function. Compared with children with a Dutch background, children with a nonwestern ethnic background had a higher odds of having current asthma (OR: 1.61, 95% CI: 1.02, 2.53), lower FVC z-score (-0.25, 95% CI: -0.35, -0.14), higher FEV /FVC z-score (0.26, 95% CI: 0.14, 0.37) and higher FEF z-score (0.15, 95% CI: 0.04, 0.25).

Conclusions: Among 10-year-old children, ethnic background was associated with current asthma and lung function after adjusting for a wide range of sociodemographic factors. No associations were found between socioeconomic status indicators and current asthma. Explanations for these associations such as language barriers, suboptimal care or pathophysiological differences require further investigation.