The impact of the environment on health by country: a meta-synthesis

Abstract

Background: Health gains that environmental interventions could achieve are main questions when choosing environmental health action to prevent disease. The World Health Organization has recently released profiles of environmental burden of disease for 192 countries.

Methods: These country profiles provide an estimate of the health impacts from the three major risk factors 'unsafe water, sanitation & hygiene', 'indoor air pollution from solid fuel use' and 'outdoor air pollution'. The profiles also provide an estimate of preventable health impacts by the environment as a whole. While the estimates for the three risk factors are based on country exposures, the estimates of health gains for total environmental improvements are based on a review of the literature supplemented by expert opinion and combined with country health statistics.

Results: Between 13% and 37% of the countries' disease burden could be prevented by environmental improvements, resulting globally in about 13 million deaths per year. It is estimated that about four million of these could be prevented by improving water, sanitation and hygiene, and indoor and outdoor air alone. The number of environmental DALYs per 1000 capita per year ranges between 14 and 316 according to the country. An analysis by disease group points to main preventions opportunities for each country.

Conclusion: Notwithstanding the uncertainties in their calculation, these estimates provide an overview of opportunities for prevention through healthier environments. The estimates show that for similar national incomes, the environmental burden of disease can typically vary by a factor five. This analysis also shows that safer water, sanitation and hygiene, and safer fuels for cooking could significantly reduce child mortality, namely by more than 25% in 20 of the lowest income countries.

Figure 1

Example of country profile of environmental burden of disease. Overlaid by reading guide for explanatory purposes.

Figure 2

Environmental DALYs per capita, by country, year 2002. Country grouping corresponds to WHO Regions (WHO 2002).

Figure 3

Environmental burden (DALYs/capita) versus GNI (Gross National Income). Country grouping corresponds to WHO Regions (WHO 2002).

Figure 4

Variability of environmental burden (DALY/capita) by GNI (Gross National Income). Countries of EBD below 75 DALYs/1000 capita. Country grouping corresponds to WHO Regions (WHO 2002). Note: The surface of data points within the graph represents the country's population size; when considering trends, larger countries therefore appear more prominently.