Socioeconomic circumstances and incidence of chronic obstructive pulmonary disease (COPD) in an urban population in Sweden

The association between socioeconomic circumstances and incidence of chronic obstructive pulmonary disease (COPD) was investigated in an urban population in Sweden. The study included all 40-89 year-old inhabitants in Malmo, Sweden (N=117,479) without previous hospitalization due to COPD, who were followed over 14 years for COPD related hospital admissions. The Malmo Preventive Project (MPP) cohort (n=27,358) with information on biological and lifestyle factors was also used to study the association between socioeconomic circumstances and COPD. The Swedish hospital discharge register was used to record incidence of COPD hospitalizations. A total of 2,877 individuals (47.5% men) were discharged from hospital with COPD as the primary diagnosis during follow-up in Malmo. Low annual income (hazard ratio (HR): 2.23; 95%CI: 1.97-2.53, P<0.001) and rented (vs. self-owned) housing (HR: 1.41; 1.30-1.52, P<0.001) were associated with a higher risk for COPD. In addition, compared to married subjects, divorced (HR: 1.61; 1.46-1.78, P<0.001) and widowed (HR: 1.30; 1.16-1.46, P<0.001) individuals had an increased risk for hospitalization due to COPD. Low income, low occupation and being divorced or widowed were similarly associated with COPD in the MPP cohort, after adjustments for smoking, FEV1, BMI, age and sex. However, socioeconomic circumstances were not associated with COPD in analyses restricted to never smokers. Low socioeconomic circumstances were associated with an increased risk of COPD after adjustments for biological and lifestyle risk factors including smoking status. However, this relationship was not significant in those who never smoked.