CONCEPT PAPER

Alternative projections of mortality and disability by cause 1990-2020: Global Burden of Disease Study

INTRODUCTION

Future health scenarios that are likely, or probable, or merely possible can have an important role in shaping public-health policy. Studies on health projections1–3 provide an indication of the strong interest shown by scientific and public-health communities in the definition and quantification of scenarios of future health. There have, however, been few comprehensive efforts to project health scenarios for a population4 and none for the entire world or for major regions. In this paper, the last of four on the Global Burden of Disease Study (GBD) (see Lancet 1997; 349: 1269–76; 1347–52; and 1436–42) we describe how we created three scenarios of future mortality and disability by cause, which may have important public policy implications. Our scenarios were based on future health status as a function of projected changes in key socioeconomic variables, which influence health states. Uncertainties in the projections arise from the validity of these relational models, assumptions about their invariance over time, and, of course, uncertainty about the future rates and distribution of factors that currently influence health and survival. Despite these uncertainties, several robust projections—due largely to demographic change and the future effects of current smoking patterns—emerge from our analysis. Further detail on the methods used to estimate causes of death, to develop epidemiological profiles of each disabling sequela, to assess the burden attributable to major risk factors, and to project the burden of premature mortality and disability has been published.

PURPOSE

Everyone, all over the world, deserves to live a long life in full health. In order to achieve this goal, we need a comprehensive picture of what disables and kills people across countries, time, age, and sex. The Global Burden of Disease (GBD) provides a tool to quantify health loss from hundreds of diseases, injuries, and risk factors, so that health systems can be improved and disparities can be eliminated.

DESCRIPTION

As part of the Global Burden of Disease Study, three scenarios of future mortality and disability were identified. The scenarios were based on future health status as a function of projected changes in key socioeconomic variables that influence health status. Regression equations for mortality rates for nine cause-of-death clusters were developed by region based on gross domestic product per person, average number of years of education, time (as a proxy for technological change), and smoking intensity. Life expectancy at birth was projected, in all three scenarios, to increase for women (to about 90 years in established market economies by 2020), with far smaller gains in male life expectancy. Worldwide, annual mortality from communicable maternal, perinatal, and nutritional disorders (group 1 causes) is expected to decline from 17.2 million to 10.3 million in 2020 in the baseline model. Also expected is a very large increase in deaths from non-communicable diseases (group 2 causes) from 28.1 million in 1990 to 49.7 million in 2020. Deaths from injuries (group 3) are projected to increase from 5.1 million to 8.4 million. Diarrheal diseases, perinatal disorders, measles, and malaria are expected to decline dramatically as causes of death in the 1990-2020 period, while lung cancer, stomach cancer, war injuries, liver cancer, and HIV are expected to move up five or more places in the ranking. In 2020, the 10 leading causes of disability-adjusted life-years (in descending order) are projected to be ischemic heart disease, unipolar major depression, road traffic accidents, cerebrovascular disease, chronic obstructive pulmonary disease, lower respiratory infections, tuberculosis, war injuries, diarrheal diseases, and HIV. Tobacco-attributable mortality is projected to increase from 3.0 million in 1990 to 8.4 million in 2020 (9% of the worldwide mortality burden).

SUPPORT

To make these results more accessible and useful, IHME has distilled large amounts of complicated information into a suite of interactive data visualizations that allow people to make sense of the over 1 billion data points generated.

Policymakers in Brazil, China, India, Indonesia, Mexico, the United Kingdom, and other countries worldwide are collaborating with GBD researchers to adopt this approach for measuring their population’s health and how it varies by different regions, socioeconomic status, or ethnic groups in their country.

CONTACT INFORMATION

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Global burden of disease (GBD): +1-206-897-2800rg