Background
Up-to-date evidence on levels and
trends for age-sex-specific all-cause and cause-specific mortality is essential
for the formation of global, regional, and national health policies. In the
Global Burden of Disease Study 2013 (GBD 2013) we estimated yearly deaths for
188 countries between 1990, and 2013. We used the results to assess whether
there is epidemiological convergence across countries.
Methods
We estimated age-sex-specific all-cause mortality using the GBD 2010
methods with some refinements to improve accuracy applied to an updated
database of vital registration, survey, and census data. We generally estimated
cause of death as in the GBD 2010. Key improvements included the addition of
more recent vital registration data for 72 countries, an updated verbal autopsy
literature review, two new and detailed data systems for China, and more detail
for Mexico, UK, Turkey, and Russia. We improved statistical models for garbage
code redistribution. We used six different modelling strategies across the 240
causes; cause of death ensemble modelling (CODEm) was the dominant strategy for
causes with sufficient information. Trends for Alzheimer's disease and other
dementias were informed by meta-regression of prevalence studies. For
pathogen-specific causes of diarrhoea and lower respiratory infections we used
a counterfactual approach. We computed two measures of convergence (inequality)
across countries: the average relative difference across all pairs of countries
(Gini coefficient) and the average absolute difference across countries. To
summarise broad findings, we used multiple decrement life-tables to decompose
probabilities of death from birth to exact age 15 years, from exact age 15
years to exact age 50 years, and from exact age 50 years to exact age 75 years,
and life expectancy at birth into major causes. For all quantities reported, we
computed 95% uncertainty intervals (UIs). We constrained cause-specific
fractions within each age-sex-country-year group to sum to all-cause mortality
based on draws from the uncertainty distributions.
Findings
Global life expectancy for both sexes increased from 65·3 years (UI
65·0–65·6) in 1990, to 71·5 years (UI 71·0–71·9) in 2013, while the number of
deaths increased from 47·5 million (UI 46·8–48·2) to 54·9 million (UI
53·6–56·3) over the same interval. Global progress masked variation by age and
sex: for children, average absolute differences between countries decreased but
relative differences increased. For women aged 25–39 years and older than 75
years and for men aged 20–49 years and 65 years and older, both absolute and
relative differences increased. Decomposition of global and regional life
expectancy showed the prominent role of reductions in age-standardised death
rates for cardiovascular diseases and cancers in high-income regions, and
reductions in child deaths from diarrhoea, lower respiratory infections, and
neonatal causes in low-income regions. HIV/AIDS reduced life expectancy in
southern sub-Saharan Africa. For most communicable causes of death both numbers
of deaths and age-standardised death rates fell whereas for most
non-communicable causes, demographic shifts have increased numbers of deaths
but decreased age-standardised death rates. Global deaths from injury increased
by 10·7%, from 4·3 million deaths in 1990 to 4·8 million in 2013; but
age-standardised rates declined over the same period by 21%. For some causes of
more than 100 000 deaths per year in 2013, age-standardised death rates
increased between 1990 and 2013, including HIV/AIDS, pancreatic cancer, atrial
fibrillation and flutter, drug use disorders, diabetes, chronic kidney disease,
and sickle-cell anaemias. Diarrhoeal diseases, lower respiratory infections,
neonatal causes, and malaria are still in the top five causes of death in
children younger than 5 years. The most important pathogens are rotavirus for
diarrhoea and pneumococcus for lower respiratory infections. Country-specific
probabilities of death over three phases of life were substantially varied
between and within regions.
Interpretation
For most countries, the general pattern of reductions in age-sex specific
mortality has been associated with a progressive shift towards a larger share
of the remaining deaths caused by non-communicable disease and injuries.
Assessing epidemiological convergence across countries depends on whether an
absolute or relative measure of inequality is used. Nevertheless,
age-standardised death rates for seven substantial causes are increasing,
suggesting the potential for reversals in some countries. Important gaps exist
in the empirical data for cause of death estimates for some countries; for
example, no national data for India are available for the past decade.
Funding
Bill & Melinda Gates Foundation.
†Collaborators listed at the end of the Article