Pulmonary gas exchange and educational level: a community study.

Socio-economic status (SES) is related to increased risk of airway disease in terms of forced expiratory volume in one second (FEV1) and forced vital capacity. No data are available as to what extent SES predicts alveolar function in a general population. In this cross-sectional study, 1,275 subjects aged 18-73 yrs underwent pulmonary testing, including the single-breath carbon monoxide transfer capacity of the lungs (TL,CO). Educational level was used as an index for SES. Mean +/- SD TL,CO % predicted was 97% among those with primary school education, 99% among those with secondary school education and 104% among those with a university degree. In a multiple linear regression analysis, adjusting for age, height, haemoglobin, carboxyhaemoglobin, smoking habits, occupational exposure, FEV1 and body mass index, TL,CO was significantly related to educational level in males but not in females. Occupational exposure was not significant. In this study, socio-economic status was found to be an independent determinant of TL,CO. Even in an affluent country such as Norway, socio-environmental risk factors may differ based on individuals' SES. Such risk factors may, for instance, be higher exposure to airborne pollutants, poorer housing conditions, or lower consumption of fruit and vegetables. Further exploration is called for.