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Non-communicable diseases now cause two thirds of deaths worldwide

BMJ 2016; 355 doi: https://doi.org/10.1136/bmj.i5456 (Published 07 October 2016) Cite this as: BMJ 2016;355:i5456
  1. Susan Mayor
  1. London

Average life expectancy across the world has increased by more than 10 years since 1980, but non-communicable diseases now account for more than two thirds of all deaths, a new analysis of global health data has shown.1

The Global Burden of Disease Study 2015 analysed the latest available data for 249 causes of death, 315 diseases and injuries, and 79 risk factors in 195 countries and territories from 1990 to 2015. Researchers estimated all cause mortality by age, sex, geography, and year using what they said was a more accurate approach than previous methods, with better estimates of child and adult mortality from an expanded database for births and deaths.

Results showed that global life expectancy from birth had increased by just over 10 years, from 61.7 years (95% uncertainty interval 61.4 to 61.9) in 1980 to 71.8 years (71.5 to 72.2) in 2015. Life expectancy in men had risen by 9.4 years, from 59.6 years in 1980 to 69 years in 2015, while in women it rose by 11.1 years, from 63.7 to 74.8 years.

The major factor that contributed to increased lifespan was a reduction in deaths from many communicable diseases, including HIV and AIDS, malaria, and diarrhoea, particularly over the past 10 years.

The number of deaths related to HIV and AIDS fell by a third (33.4%) from 2005 to 2015, from 1.8 million to 1.2 million deaths. Deaths from malaria showed a similar reduction over the same period (37%), falling to 730 500 deaths in 2015.

Just over 70% (40 million) of global deaths in 2015 were caused by non-communicable diseases. The leading causes of these deaths were cardiovascular disease, cancers, and chronic respiratory diseases, but they also included stroke, diabetes, chronic kidney disease, Alzheimer’s disease, and other dementias.

Further analysis of the data showed that healthy life expectancy increased by only 6.1 years from 1990 to 2015, which was less than the 10.1 year increase in overall life expectancy.2 This showed that people were spending more years living with illness and disability.

The main causes of disability adjusted life years (DALYs) lost to premature death and disability have shifted from communicable, maternal, and neonatal causes and malnutrition to disabling non-communicable diseases. Ischaemic heart disease and stroke were the leading two causes of DALYs worldwide in 2015, but other causes included diabetes, osteoarthritis, drug use disorders, depression, and hearing and vision loss. The researchers found that this trend was mainly caused by increases in population numbers and ageing.

Christopher Murray, director of the Institute for Health Metrics and Evaluation at the University of Washington in Seattle, which coordinated the study, said, “Health is improving globally, but this means more populations are spending more time with functional health loss.”

Murray added, “Demographic changes leading to increased population size and older average age have offset otherwise important gains in age specific DALY rates, leading to a rising burden on health systems for many ailments of ageing.”

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