Determinants of exposure to environmental tobacco smoke in 21,588 Italian non-smokers

Background: Exposure to environmental tobacco smoke (ETS) is associated with an increased risk of lung cancer, ischemic heart disease and respiratory diseases in non-smokers. Exposure is likely to be uneven in the population. Knowledge of its distribution is important for a better planning of preventive activities. Methods: In the context of the Italian branch of the EPIC prospective investigation, in which we enrolled 47,000 volunteers, we have surveyed exposure to ETS and its determinants (age, social class, occupation). The purpose of the present paper is to contribute to identify the main sources of exposure in Italy. Results: We found, in a sample of 21,588 Italian non-smokers, a prevalence of 0.337 (95% confidence interval, 0.336-0.337) in women and 0.537 (0.529-0.544) in men. Exposure was defined as at least 1 hr/day for at least one year. Exposure at work is by far the commonest source of exposure to ETS, with a strong difference between full-time and part-time jobs. The distribution of exposure by social class was uneven, with statistically significant odds ratios for higher social groups in the order of 0.4-0.5. White-collar workers are the occupational category mostly exposed, suggesting that the implementation of anti-smoking legislation is still incomplete in Italian offices. Conclusions: The uneven distribution of ETS in the population is a matter of concern, since it contributes to the unequal distribution of health in different social groups.