Social class, smoking and the severity of respiratory symptoms in the general population

Abstract

Study objective: The prevalence of respiratory symptoms has been found in some studies to vary with social class. One explanation of this link may be the effect of exposure to cigarette smoke. To investigate this, the relation between social class, smoking and respiratory symptoms was explored in a population based survey.

Design: A cross sectional survey using a validated questionnaire.

Setting: Two general practices in Staffordshire, United Kingdom.

Patients: A random sample of 4237 patients aged 16 and over from two general practices in Staffordshire were mailed a questionnaire enquiring about respiratory symptoms and their severity.

Main results: The severity of respiratory symptoms increased with increasing exposure to cigarette smoke and was greater among manual social classes. Current smokers (odds ratio (OR) = 2.9, 95% confidence limits (CI) 2.3, 3.6), past smokers (OR = 1.5, 95% CI 1.2, 1.8) and passive smokers (OR = 1.4, 95% CI 1.0, 1.8) were more likely to report the more severe respiratory symptoms compared with non-smokers. Responders from social class V (OR = 2.4, 95% CI 1.3, 4. 4) were more likely to report the more severe respiratory symptoms compared with social class I, as were responders from social classes IIIM (OR = 1.3, 95% CI 0.9, 1.9) and IV (OR = 1.4, 95% CI 0.9, 2.1). These effects were independent of each other.

Conclusions: This study has shown that social class is linked to the severity of respiratory symptoms, independently of smoking. Although the need to reduce and quit smoking in manual class households remains a crucial preventive issue, other mechanisms by which social class differences may influence symptom occurrence and severity need to be explored.