Socioeconomic status, lifestyle factors and asthma prevalence: results from a population-based study in Sweden

To examine differences in the prevalence of self-reported diagnosed asthma by socioeconomic status and the contribution of lifestyle factors to these differences.

The study was based on 28,531 persons aged 18 years or older who answered a survey questionnaire sent to a random population sample in mid-Sweden in 2017. The overall response rate was 44%. Socioeconomic status was measured with educational level and economic difficulties, and lifestyle factors with physical activity, smoking, snuff use, risk-drinking of alcohol and obesity. The associations between socioeconomic status and asthma were analysed using multivariate logistic regression.

The overall asthma prevalence was 9% among women and 7% in men and decreased with increasing age. Educational level was not independently associated with asthma, but a statistically significant odds ratio (with 95% confidence intervals) for the prevalence of asthma was observed for economic difficulties 1.5 (1.3-1.7). Also, physical inactivity 1.2 (1.1-1.3) and obesity 1.6 (1.4-1.8) were associated with increased asthma prevalence. Smoking and risk-drinking were not statistically significantly associated with asthma whereas snuff users had a higher prevalence of asthma among women. Adjusting for lifestyle factors did not affect the association between socioeconomic status and asthma.

In this population-based study, self-reported diagnosed asthma was independently associated with economic difficulties but not with educational level. Lifestyle factors did not explain the association between economic difficulties and asthma prevalence. This applies to both men and women as well as younger and older age groups.