Studies on the influence of alcohol consumption on lung function have shown conflicting results. Self-reported alcohol consumption may be inaccurate. This study used both a validated alcohol questionnaire and a blood marker of heavy alcohol consumption, and examined potential associations with different lung physiological variables.

The study population (450 subjects) answered an alcohol questionnaire (AUDIT-C) and performed spirometry, body plethysmography and a test for diffusing capacity for CO (D_L,CO). Carbohydrate deficient transferrin (CDT), a clinically used blood marker for identifying heavy alcohol consumption, and C-reactive protein (CRP), a marker of systemic inflammation were analysed.

Using AUDIT-C, 407 subjects were alcohol drinkers and 29 non-drinkers. Of the alcohol drinkers, 224 subjects were “hazardous drinkers” and 183 “moderate drinkers”. Thirty-four subjects had a CDT ≥2.0% (=heavy drinkers). There was no difference in lung function between hazardous and moderate drinkers. Heavy drinkers had lower D_L,CO (74% vs 83% PN, p = 0.003), more symptoms of chronic bronchitis (p = 0.001) and higher AUDIT-C scores (p < 0.001) than non-heavy drinkers. After adjustments (pack years and CRP) the difference in D_L,CO (p = 0.037) remained. Multiple regression showed an association between CDT and both FEV₁ (p = 0.004) and D_L,CO (p = 0.012) in all alcohol drinkers, but not in never-smokers. The AUDIT-C score was associated with CDT (also after adjustments, p < 0.001) but not with any lung function variable.

The results from this study suggest that alcohol and particularly heavy drinking has an independent additive negative effect on lung function in smokers.