Environmental Tobacco Smoke (ETS): Health hazard to children

ETS is now recognized as an important problem for public health, and infants and children are among the most susceptible populations. According to WHO (1), around 700 million, almost half of the world's children, were estimated to be exposed to ETS, particularly at home. Epidemiological evidence is sufficiently strong to provide robust exposure-response functions, and no level of exposure is considered safe.

Prenatal and postnatal ETS exposure causes a wide range of effects on mortality and morbidity in children. Maternal exposure to ETS (2) and smoking during pregnancy is associated with a low birth weight (3). Postnatal exposure to ETS leads to acute health effects. Parental smoking doubles the risk for Sudden Infant Death Syndrome (SIDS) (4), and is causally associated with an increased incidence of lower respiratory illnesses, chronic respiratory symptoms (wheeze and cough), middle ear infections and asthma episodes (5).

In ENHIS-2, a health impact assessment (HIA) of ETS was carried out for SIDS and asthma episodes in a set of 18 European countries (Austria, Bulgaria, Czech Republic, Finland, France, Germany, Greece, Hungary, Italy, Lithuania, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain and United Kingdom). Current smoking prevalence for males in each country (WHO Tobacco control database) was considered a suitable proxy for estimates of children ETS exposure. Different scenarios of smoking prevalence were analysed: current prevalence, and 20, 30, 40 and 50% smoking prevalence.

For SIDS, the pooled Odds Ratio (OR) of 1.94 (1.55-2.43)4 was considered the most appropriate exposure-response function for this HIA. Children population and number of SIDS in each country were retrieved from Eurostat databases for 2003. For the lowest exposure scenario (20%), a plausible range between 110 and 250 SIDS cases would be attributed to ETS (10 to 22%). For the highest exposure scenario (50%), this range would stand between 250 and 480 cases (22 to 42%). Considering the current smoking prevalence in participating countries, about 25% of all SIDS cases could be related to ETS exposure at home.

On the other hand, the most recent meta-analysis provided an OR of 1.23 (1.14-1.33) (5) for asthma episodes when either parent smoking. Asthmatic children are especially at risk of ETS exposure in their homes. It was estimated that exposure to ETS increases the number of asthma episodes by 6% to 10%, depending on the current smoking prevalence in each country. The average amounts to 7.5% in participating countries. Austria, Greece and Bulgaria stand in the upper limit of this range.

The HIA findings showed that the number of cases attributable to ETS varies between countries depending on the levels of smoking in those regions. An important issue in quantifying the number of cases related to this risk factor in European children is to determine how to estimate ETS exposure. In relation to health data, routine data on asthma symptoms prevalence are not available for most of the countries or they are not comparable between countries.

In conclusion, ETS causes a number of non-fatal (asthma episodes) and fatal (SIDS) health effects. In view of the considerable health impact of ETS on children, measures to restrict smoking in indoor environments should be a major public health objective. Particularly, reducing children’s ETS exposure should focus on promoting smoke-free homes and cars.

Go to indicator Exposure of children to environmental tobacco smoke

References

1. WHO. Tobacco Free Iniciative. International Consultation on Environmental Tobacco Smoke (ETS) and Child Health. Geneva, Switzerland. 1999.
2. Hofhuis W, de Jongste JC, Merkus PJ. Adverse health effects of prenatal and postnatal tobacco smoke exposure on children. Arch.Dis.Child 2003; 88: 1086-90..
3. Windham GC, Eaton A, Hopkins B. Evidence for an association between environmental tobacco smoke exposure and birthweight: a meta-analysis and new data. Paediatr.Perinat.Epidemiol. 1999; 13: 35-57.
4. Anderson HR,.Cook DG. Passive smoking and sudden infant death syndrome: review of the epidemiological evidence. Thorax 1997; 52: 1003-9.
5. US Surgeon General. The health consequences of involuntary exposure to tobacco smoke: a report of the Surgeon General. U.S. Dept. of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, Atlanta, Georgia. 2006.