World population gains more than 6 years of life expectancy since 1990

Global life expectancy increased by 5.8 years in men and 6.6 years in women between 1990 and 2013, according to a major new analysis from the Global Burden of Disease Study 2013 (GBD 2013).

However, some causes of death ran counter to these trends and have seen increased rates of death [1] since 1990, including: liver cancer caused by hepatitis C (up by 125%), atrial fibrillation and flutter (serious disorders of heart rhythm; up by 100%), drug use disorders (up by 63%), chronic kidney disease (up by 37%), sickle cell disorders (up by 29%), diabetes (up by 9%), and pancreatic cancer (up by 7%).

In high-income regions, falling death rates from most cancers (down by 15%) and cardiovascular diseases (down by 22%) have increased life expectancy, while rapidly declining death rates for diarrhea, lower respiratory tract infections, and neonatal disorders have helped extend life expectancy in low-income countries.

While life expectancies are increasing throughout the world, there is one notable exception: southern sub-Saharan Africa, where deaths from HIV/AIDS have erased over 5 years of life expectancy.

"The progress we are seeing against a variety of illnesses and injuries is good, even remarkable, but we can and must do even better," says lead author Dr Christopher Murray, Professor of Global Health at the University of Washington in the USA. "The huge increase in collective action and funding given to the major infectious diseases such as diarrhea, measles, tuberculosis, HIV/AIDS, and malaria has had a real impact. However, this study shows that some major chronic diseases have been largely neglected but are rising in importance, particularly drug disorders, liver cirrhosis, diabetes, and chronic kidney disease."

The findings come from GBD 2013, the most comprehensive and up-to-date estimates of the number of yearly deaths due to 240 different causes in 188 countries over 23 years (1990 to 2013). The amount of data in GBD 2013 have been significantly expanded from GBD 2010 to include both more data from certain countries (China, Russia, Turkey), and additional data on conditions such as cancers and HIV/AIDS.

Key findings include:

• Some low-income countries have made exceptional gains in life expectancy over the past 23 years. For example, in Nepal, Rwanda, Ethiopia, Niger, Maldives, Timor-Leste, and Iran life expectancy has increased by more than 12 years for both sexes.
• Despite dramatic drops in child deaths over the last 23 years (from 7.6 million in 1990 to 3.7 million in 2013, in children aged 1-59 months), lower respiratory tract infections, malaria, and diarrheal disease are still in the top 5 global causes of death in children younger than 5 years and continue to kill almost 2 million children between the ages of 1 and 59 months every year.
• Another mixed success is that while worldwide deaths from HIV/AIDS have declined substantially every year since its peak in 2005, HIV/AIDS is still the greatest cause of premature death in 20 of 48 countries in sub-Saharan Africa.
• The top ten leading causes of premature death worldwide have hardly changed since 1990. Nine causes remained in the top ten in 2013, with HIV/AIDS moving in and tuberculosis moving to 11^th. Worldwide, since 1990, years of life lost due to HIV/AIDS have increased by 344%, drug disorders by 119%, chronic kidney disease by 90%, and Alzheimer's disease by 89%.
• The UK has seen lower life expectancy increases than the global average of 6.2 years. Between 1990 and 2013, life expectancy at birth increased from 72.9 years to 79.1 years for men and from 78.4 years to 82.8 years for women.
• War is the leading cause of premature death in Syria. The conflict in Syria has killed an enormous number of people. In 2013, there were an estimated 29947 deaths (between 19392 and 54903 [2]) and about 10504 deaths and 21422 deaths in each of the preceding two years.
• In eastern Europe, half of all premature deaths in 2013 were due to five causes: ischemic heart disease, stroke, self harm, cirrhosis, and road injury.
• In India, life expectancy at birth increased from 57.3 years to 64.2 years for men between 1990 and 2013 and 58.2 years to 68.5 years for women during the same time period. India has made remarkable progress in reducing child and adult deaths with death rates dropping 1.3% per year for adults and 3.7% for children. Suicide is a major and growing public health problem in India with half of the word's suicide deaths occurring in India and China alone.
• Road injury and Interpersonal violence are key contributors to premature deaths in Latin America and the Caribbean, ranking in the top five leading causes for 17 and 15 out of 29 countries in the region, respectively. Outside this region, interpersonal violence only ranks in the top five causes in just one other country in the world: South Africa.

Writing in a linked Comment, Igor Rudan and Kit Yee Chan from the Centre for Population Health Sciences and Global Health Academy at the University of Edinburgh Medical School in the UK call for continuing competition between research groups to improve science. They write that, "Estimates of the causes of the global burden of disease, disability, and death are important because they guide investment decisions that, in turn, save lives across the world. Historically, the responsibility for those estimates rested largely with WHO and its academic partners. Although WHO's team of experts have been doing fine technical work for many years, its monopoly in this field had removed incentives to invest more time and resources in continuous improvement. The emergence of the Institute for Health Metrics and Evaluation, generously supported by the Bill & Melinda Gates Foundation, has changed the science of global health metrics in a similar way to Celera Genomics' competition with the Human Genome Project…the competition between WHO and the GBD has benefited the entire global health community, leading to converging estimates of the global causes of death that everyone can trust."

[1] Death rates age standardized per 100,000 population

[2] Uncertainty around these estimates is large because several different estimates exist. These estimates are of the direct deaths resulting from armed conflicts and do not account for the full effects of associated factors such as the breakdown of health systems or critical infrastructure.