Effect of smoking on use of antibacterials: a 9-year follow-up study of 24 000 working-aged Finns.

Background Previous studies indicate an association between tobacco smoking and infectious diseases. However, large population-based follow-up studies including both accurate measurements of smoking behaviour and confounders and a reliable register-based follow-up of infections are lacking. Objective To examine the effect of smoking on use of antibacterials as an indicator of infections among working-aged population. Methods The participants of the population-based Health and Social Support Study (24 283 working-aged Finns) were followed up for 9 years. Information on smoking behaviour and confounders was obtained from a questionnaire in 1998. Number of antibacterial purchases was obtained from the National-Drug-Prescription- Register. The association between smoking and use of antibacterials was analysed using multinomial regression models. Results A graded association between lifetime smoking as measured by pack-years and use of antibacterials was found. Compared with never-smokers, the age-adjusted OR for multiple use of antibacterials among smokers with 12 or more pack-years was 2.32 (95% CI 1.91 to 2.82) in women and 1.45 (95% CI 1.23 to 1.71) in men. The associations remained after adjustment for the following confounding factors: use of alcohol, body mass index, physical activity, socioeconomic status, hard physical work, life satisfaction, disability pension and dyspnoea. Conclusions Smoking is associated with increased use of antibacterials. Infectious periods experienced by patients should be used as an opportunity to encourage smoking cessation.