Effects of environmental tobacco smoke on the respiratory health of adults.

In this paper, current knowledge on the respiratory effects of environmental tobacco smoke among adults is synthesized, and the biological basis and methodological issues are discussed. The Medline database was searched from 1966 through October 2000. All of the related respiratory effects have been linked to both home and workplace exposures. Some evidence of a dose-response relation has also been detected for all respiratory conditions. The strongest evidence of a causal relation exists for chronic respiratory symptoms. Harmful effects on lung function have also been detected, mainly in countries and occupations with high exposure levels. There is limited evidence indicating an increased risk of its causing asthma and chronic obstructive pulmonary disease, and also for poor control of established asthma. More longitudinal studies with careful assessment of exposure are needed for better risk estimates. Despite these challenges for the future, the combination of toxicologic evidence, abundant evidence on respiratory effects among children, and the studies reviewed in this paper point to an urgent need for measures to prevent exposure to environmental tobacco smoke among adults.