Underweight the main cause of ill-health; five causes account for 28% of all DALYs

Childhood and maternal underweight, unsafe sex, high blood pressure, tobacco, and alcohol are the five main causes of today's global burden of disease, in that order, of 25 health risks chosen for study by the Comparative Risk Assessment Collaborating Group, an international team whose research forms the basis for this year's World Health Report (see WHO News).

According to the study, these five causes account for 28% of total disability-adjusted life years (DALYs) lost to ill-heath each year. Childhood and maternal underweight causes 138 million DALYs (9.5% of total), unsafe sex 92 million (6.3%), high blood pressure 64 million (4.4%), tobacco 59 million (4.1%), and alcohol 58 million (4.0%).

However, the ranking varies according to the state of development of countries. In the poorest regions of the world the third, fourth and fifth most important risk factors are unsafe water, sanitation, and hygiene; indoor smoke from solid fuels; and micronutrient deficiencies, while underweight and unsafe sex remain the first and second. Alcohol, tobacco, high blood pressure, and high cholesterol are major causes of disease burden in both developing and developed regions, the study concludes.

This analysis of health by risks could not, however, include some important diseases, such as TB and malaria, which have multiple causes and influences varying from one group of people to another. Such diseases, say the researchers, are best suited to analysis of specific interventions tailored to specific settings, rather than to risk factor analysis.

The Comparative Risk Assessment Collaborating Group consist of a team of over 140 experts from WHO and institutions predominantly in Australia, New Zealand, the United Kingdom and the United States, but also including institutions based in Canada, Chile, Mexico, South Africa, Spain, Sweden, and Switzerland, plus UNAIDS. Their study has been published in the Lancet and is available on the WWW ( 02art9066web.pdf).

Robert Walgate, Bulletin

World Health Organization Genebra - Genebra - Switzerland