Prevalence of COPD by age, sex, socioeconomic position and smoking status; a cross-sectional study

Abstract

PurposeThe purpose of this study is to calculate gender and socioeconomic status (SES) inequalities in chronic obstructive pulmonary disease (COPD) in Greater Glasgow and Clyde and measure the proportion of inequalities explained by smoking.Design/methodology/approachMedical records until May 2016 were linked to mortality data to measure COPD prevalence. Population estimates for smoking status were calculated by merging three (2013–2015) Scottish Household Survey rounds. Poisson regression was carried out to analyse the relationship between SES and gender inequalities in COPD, and smoking.FindingsCrude COPD prevalence for ages 16+ years was 3.29% and for ages 45 years+ was 6.26%, and higher in females than males. Adjusting for age and sex, prevalence of COPD in the most deprived quintile was 4.5 times of that in the least deprived. Adjustment for smoking explains almost half of the relative difference between Scottish Indicator for Multiple Deprivation (SIMD) 1 (least affluent quintile of deprivation) and SIMD 5 (most affluent quintile) and a fifth of the absolute difference. There is a higher risk of COPD among male non-smokers than female, but among smokers the risk is greater for females than males.Research limitations/implicationsRisk factors specific to respiratory health beyond smoking and common risk factors of morbidity more generally should be considered in understanding inequalities in COPD.Originality/valuePrevalence of COPD is higher than previously thought. Smoking explains less than half of inequalities in COPD. Gender inequalities in COPD are dependent on smoking status and the smoking indicator used.