London School of Hygiene & Tropical Medicine

The key drivers of ill health, disability, and death worldwide have been revealed in the most-up-to-date analysis on the state of the world's health, published in The Lancet. The Global Burden of Disease, Injuries and Risk Factors (GBD) 2015 study provides governments, donors and other stakeholders with evidence to identify national health challenges and intervention targets.

The huge study includes researchers from the London School of Hygiene & Tropical Medicine and brings together 1,870 experts in 127 countries and territories.

The GBD 2015 looks at 249 causes of death, 315 diseases and injuries, and 79 risk factors across 195 countries and territories between 1990 and 2015. The findings show that although health is improving globally, progress has been far from universal, highlighting where improvements must be made.

For the first time, the study also includes a measure of development based on income per capita, educational attainment and fertility rate, called the Socio-Demographic Index (SDI). This helps determine a country's observed performance against their expected performance based on their stage of development.

Dr Heidi Larson, Associate Professor at the London School of Hygiene & Tropical Medicine and Director of European Initiatives at the Institute for Health Metrics and Evaluation, which coordinates the GBD, said:

"These estimates offer important insights into the drivers of disease, disability and death in countries around the world. Economic development is not the only factor that influences health, and some countries have improved much faster than we would expect. However, while people's health is improving globally, there are still large disparities which need to be addressed.

"Even developed countries are failing to meet targets despite the wealth of resources available to them. For example, smoking is a highly preventable risk and although exposure to smoking has fallen significantly, it still remains the leading risk factor for poor health in the UK and USA and continues to rank as a top five risk in hundreds of countries worldwide."  

The study found that the world population has gained more than a decade of life expectancy since 1980, rising to an average of 69 years in men and 74.8 years in women in 2015. Women born in 2015 in the UK can expect to live to 82.8 years on average, with men averaging an age of 79.

Although healthy life expectancy has increased steadily in 191 of 195 countries, it has not risen as much as overall life expectancy, meaning people are living more years with illness and disability.

Globally, seven out of ten deaths in 2015 were due to non-communicable diseases such as heart disease, stroke, diabetes, chronic kidney disease and dementia.

High blood pressure, smoking, high blood sugar, high body mass index, and childhood undernutrition were the world's leading risk factors for premature death in 2015.

The study shows there has been progress in maternal health, with maternal deaths falling by nearly a third since 1990, from 282 deaths per 100,000 live births in 1990 to 196 in 2015. However, 275,000 women still died in pregnancy or childbirth in 2015, mostly from preventable causes.

Worldwide, the number of deaths in children under the age of 5 has more than halved from 12.1 million in 1990 to 5.8 million in 2015, and the gap between groups of countries with the lowest and highest rates of child mortality is shrinking. However, the world fell short of the Millennium Development Goal target to reduce child mortality by two thirds between 1990 and 2015.

One area that needs special attention is neonatal (in first month life) deaths which are falling more slowly than under-5 deaths and accounted for nearly half (2.6 million) of all deaths in children under 5 in 2015.

The GBD 2015 studies were funded by The Bill & Melinda Gates Foundation.

Publication:

• Global Burden of Disease Study, 2015, The Lancet (links to six papers)