Background: During the second half of the 20th century the prevalence of asthma has increased and smoking habits and socioeconomy has changed in Sweden.

Aim: To analyze risk factor patterns for current asthma in 1996, 2006 and 2016.

Methods: Three cross-sectional random samples from the same area of Sweden, 20-69 years, participated in population surveys with the same validated questionnaire in 1996 (n=7104 participants, 85% response rate), 2006 (n=6165, 77%) and 2016 (n=5466, 53%). Current asthma was defined as physician-diagnosed asthma with symptoms common in asthma and/or asthma medication use during the last 12 months. Socioeconomic classification was based on occupation. Risk factors for current asthma were analyzed by multivariable logistic regression.

Results: A family history of asthma yielded the highest odds ratios (OR) all three years with ORs 3.19-3.66. Data on occupational exposure to gas, dust or fumes (GDF) was not available in 1996, but associated with current asthma in both 2006 (1.86, 1.51-2.30) and 2016 (1.70, 1.37-2.10). Ex-smoking was a risk factor in 1996 (1.39, 1-12-1.73) and 2006 (1.38, 1.11-1.71) but not in 2016 (1.15, 0.92-1.44). Manual workers in service and industry, non-manual employees and self-employed had increased risk for current asthma in 2016, but not in 1996 or 2006, compared to professionals and executives.

Conclusion: The risk factor pattern for asthma among adults has changed in Sweden from 1996 to 2016. While occupational exposure to GDF was a prominent and constant risk factor for asthma, ex-smoking lost significance in 2016, and socioeconomic differences with regard to occupation emerged.