Quantifying environmental health impacts

Burden of disease attributable to selected environmental factors and injuries among Europe's children and adolescents

Environmental Burden od Disease Series No. 8


Summary

Although exposures to environmental risks contribute significantly to the burden of disease among children and adolescents (Smith, Corvalan & Kjellstrom, 1999; WHO, 2002), there are still gaps in our knowledge about the magnitude and regional distribution of the environmental burden of disease (EBD) among the young. For the WHO European Region in particular, there are no estimates. This study aims to estimate the burden of childhood disease and injury attributable to environmental risks in the WHO European Region, as well as the health gains that could be achieved by reducing the exposure of the child population to these risks.

We analysed five environmental risks factors:

  • outdoor air pollution
  • indoor air pollution
  • water, sanitation, and hygiene
  • lead
  • injury.

The burden of disease was measured in terms of the disability-adjusted life year (DALY), a summary measure that accounts for the impact both of “premature” death (i.e. the years of life lost due to premature death, or YLL), and of health problems among those who are alive (i.e. the number of years lived with a disability, or YLD). For the purpose of this study, we also considered the environment in a broad sense, and included both the physical and socioeconomic settings. For this reason, we present the burden of all injuries, not just those directly attributable to the physical environment, such as occupational or domestic hazards. The methods used to estimate the burden of child disease attributable to each risk factor are described separately for each risk factor, and are consistent with those developed by WHO for the Global Burden of Disease (GBD) study (WHO, 2000a). Since patterns of morbidity and mortality vary across the European Region, and environmental factors are likely to be at least partly responsible for such differences, the analyses were performed separately for each of the three WHO European subregions, EUR A, EUR B, and EUR C (see Annex 1 for a list of the Member States in each subregion and for a description of the inclusion criteria). This follows the classification used by WHO (WHO-CHOICE, 2003).

The year 2001 was chosen as the reference year because it ensured a good balance between availability of data and timeliness. Age groups included in the analyses were 0-4, 5-14 and 15-19 years. The age group 15-19 years was used so as to include the entire adolescent population and ensure comparability with other studies. Due to the limited availability of complete data on exposures and health effects in all age groups, estimates of the disease burden attributable to certain risk factors did not include the complete child age range (0-19 years) and should therefore be considered conservative.

The burden of disease attributable to the five environmental risks accounted for one third of the total disease burden for children 0-19 years of age in the EUR Region. Among children 0-4 years of age, the five risks contributed to 21.9-26.5% of all deaths and to 19.8% of all DALYs. Among those 5-14 years old, the risks contributed to 42.1% of all deaths and to 30.8% of all DALYs. Among those 15-19 years old, the risks were responsible for 59.9% of all deaths and for 27.1% of all DALYs. Children living in EUR B and EUR C suffered the most from exposures to the environmental risk factors. Injuries were the leading cause of deaths and DALYs in all age groups in EUR A and among children and adolescents 5-14 years old and 15-19 years old in EUR B and EUR C.

Given the scarcity of published and available literature from certain countries, results of this study may be skewed towards those with available data. More uniform and widespread collection of environmental exposure data, as well as regional standardization and routine collection of morbidity and mortality statistics, are needed to improved burden of disease estimates.

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