Is there still a social gradient in respiratory symptoms? A population-based Nordic EpiLung-study

Abstract

Background: Respiratory symptoms are a common public health issue that can partly be attributed to preventable risk factors, such as tobacco smoking and occupational exposure, which are more common in individuals with lower socioeconomic status. Objective: Our aim was to evaluate the social gradient in respiratory symptoms in Nordic countries. Methods: This study included participants aged 30–65 years from five cross-sectional population-based questionnaire surveys in 2016 in Finland and Sweden (N = 25,423) and in 2017–2019 in Norway (N = 27,107). Occupational skill levels 1 and 2 (occupations requiring compulsory education) were combined and compared to skill levels 3 and 4 (occupations requiring upper secondary and tertiary education). Meta-analysis was conducted to obtain pooled age- and sex adjusted odds ratios (aORs) of associations between occupational skill and the respiratory symptoms including recurrent wheeze, dyspnoea, and productive cough. Results: In the meta-analysis, recurrent wheeze, dyspnoea, and productive cough showed a social gradient. The participants with occupational skill 1 and 2 had higher risk for recurrent wheeze (aOR 1.78, 95% CI 1.34–2.22) and dyspnoea (aOR 1.59, 95% CI 1.29–1.90) compared to occupational skill 3 and 4 in Sweden and Finland. Similarly increased risk was observed for combined assessment of dyspnoea and wheeze (aOR 1.05, 95% CI 1.03–1.07) in Norway. In a meta-analysis including all three countries, the aOR for productive cough was 1.31 95% CI 1.07–1.56. Conclusions: Occupations with lower, compared to higher, skill levels were associated with an increased risk of recurrent wheeze, dyspnoea, and productive cough.