Environmental exposures at home and in the workplace in relation to inhaled corticosteroid medication - the population-based REGAL study.

BACKGROUND

Diverse environmental exposures - home, occupational, and traffic-related - may impact asthma, but population-based studies on objectively assessed asthma are lacking. We aimed to investigate the impact of these exposures on future inhaled corticosteroid (ICS) use.

METHODS

Data from two Swedish population-based cohorts (performed in 2008-2010) were linked to the National Prescribed Drug Registry from 2005 to 2018 to form the REGAL study. This analysis included 31,768 participants from Stockholm, Gothenburg, Uppsala, and Umeå. Participants reported asthma diagnosis, asthma-related symptoms, and home and occupational exposures via questionnaires, while ICS prescriptions were retrieved from registry.

RESULTS

Among 31,768 participants, 6.9% (n = 2,103) reported asthma medication via questionnaire at baseline, and 5.3% (n = 1,679) initiated ICS therapy during the follow-up period (median follow-up time: 10.7 years). The prevalence of floor dampness, irritating air at home, traffic exposure at home, and occupational exposure to gas, smoke, or dust were 3.8%, 17.9%, 4.0%, and 36.7%, respectively. Floor dampness (odds ratio OR = 1.32, 95%CI 1.06-1.63), irritating air (OR = 2.08, 95%CI 1.85-2.33), traffic exposure at home (OR = 1.48, 95%CI 1.21-1.81), and occupational exposure to gas, smoke, or dust (OR = 1.55, 95%CI 1.39-1.72) were associated with self-reported asthma medication. An increased risk of initiating ICS therapy during the follow-up period was found for floor dampness at home (hazard ratio HR = 1.42, 95%CI 1.14-1.77), irritating air at home (HR = 1.46, 95%CI 1.29-1.65), and previous occupational exposure to gas, smoke, or dust (HR = 1.25, 95%CI 1.12-1.40).

CONCLUSIONS

Indoor dampness, irritating air at home, and occupational exposure to gas/smoke/dust were associated with self-reported asthma medication at baseline and future initiation of ICS.