Background: Global and regional estimates show that non-communicable diseases in old age are rising in importance relative to other causes of ill health as populations age, and as progress continues against communicable diseases among infants and children. However, these estimates, which cover population groups at all income levels, do not accurately reflect conditions that prevail among the poor. We estimated the burden of disease among the 20% of the global population living in countries with the lowest per capita incomes, compared with the 20% of the world's people living in the richest countries.
Methods: Estimates for the global poorest and richest 20% were prepared for 1990 for deaths and disability-adjusted life years (DALYs), by a procedure used in a prominent recent study of the global disease burden. Projected mortality rates in the year 2020 were established for the world's poorest and richest 20% under various assumptions about the future rate of decline in communicable and non-communicable diseases.
Findings: In 1990, communicable diseases caused 59% of death and disability among the world's poorest 20%. Among the world's richest 20%, on the other hand, non-communicable diseases caused 85% of death and disability. A raised baseline rate of communicable disease decline between 1990 and 2020 would increase life-expectancy among the world's poorest 20% around ten times as much as it would the richest 20% (4.1 vs 0.4 years). However, the poorest 20% would gain only around a quarter to a third as much as the richest 20% from a similar increase in non-communicable diseases (1.4 vs 5.3 years). As a result, a faster decline in communicable diseases would decease the poor-rich gap in 2020, but under an accelerated rate of overall decline in non-communicable diseases, the poor-rich gap would widen.
Interpretation: Our estimates are crude, but despite their limitations, they give a more accurate picture of changes in attributable mortality among the world's poor than do the global averages in current use.
PIP: This study presents the burden of disease among the poor globally. The burden of disease among the poorest 20% of the population, was compared to that among the richest 20% using deaths and disability-adjusted life years (DALYs). Projected mortality rates for the richest and poorest were established under various assumptions about the decline in the communicable and noncommunicable disease rates. Results showed that among the poorest 20% of the world's population (1990), communicable diseases caused 59% deaths and 64% DALY loss; noncommunicable disease caused 85% of death and DALY loss. Among the world's richest 20%, communicable diseases accounted for 8% of deaths and 11% of DALY loss. A raised baseline rate of communicable disease decreases between 1990 and 2020 would increase life expectancy among the worlds poorest 20% by about 10 times the rate that it would increase life expectancy among the richest 20%. However, the poorest would gain only around quarter to a third as much as the richest 20% from a similar increase in the decline of noncommunicable diseases. Therefore, a faster overall decline in communicable diseases would decrease the poor/rich gap in 2020, but under an accelerated overall decline in noncommunicable diseases, the poor/rich gap would widen. The authors concede that the data presented are only rough estimates, but they believe that these estimates give a more accurate picture of changes in attributable mortality than do the global averages in current use.