High blood pressure, smoking, and poor dietary habits are greatest risk factors for death

Sep 11 2015

A huge international study of global causes of death has revealed that since 1990, there has been a profound change in risk factors for death.

In 1990, child and maternal malnutrition and unsafe water, sanitation, and lack of hand washing were the leading risks for death, but these have now been replaced by dietary risks and high blood pressure.

The findings are from a new analysis of global cause-of-death data published in The Lancet today.

The study was conducted by an international consortium of researchers working on the Global Burden of Disease project and led by the Institute for Health Metrics and Evaluation (IHME) and led by the University of Washington and the University of Melbourne.

Researchers looked at 79 risk factors for death in 188 countries between 1990 and 2013.

The risk factors examined in the study contributed to almost 31 million deaths worldwide in 2013, up from 25 million deaths in 1990.

Top risk factors worldwide include:

• In much of the Middle East and Latin America, high body mass index is the number-one risk associated with health loss.
• In South and Southeast Asia, household air pollution is a leading risk, and India also grapples with high risks of unsafe water and childhood under-nutrition.
• Alcohol is the number-two risk in Russia.
• Smoking is the number-one risk in many high-income countries, including the United Kingdom.
• The most marked differences are found in sub-Saharan Africa, which, unlike other regions, is dominated by a combination of childhood malnutrition, unsafe water and lack of sanitation, unsafe sex, and alcohol use.
• Wasting (low weight) accounts for one in five deaths of children under five-years-old, highlighting the importance of child malnutrition as a risk factor.
• Unsafe sex took a huge toll on global health, contributing to 82 per cent of HIV/AIDS deaths and 94 per cent of HIV/AIDS deaths among 15- to 19-year-olds in 2013. This has a greater impact on South Africa than any other country, 38 per cent of South African deaths were attributed to unsafe sex. The global burden of unsafe sex grew from 1990 and peaked in 2005.

The study included several risk factors - wasting (low weight for a person's height), stunting (low height for a person's age), unsafe sex, HIV, no hand-washing with soap, intimate partner violence - in its analysis for the first time.

"There's great potential to improve health by avoiding certain risks like smoking and poor diet as well as tackling environmental risks like air pollution," IHME Director Dr Christopher Murray said.

"The challenge for policymakers will be to use what we know to guide prevention efforts and health policies."

The Australian context

The top risks associated with the deaths of both men and women in Australia are high blood pressure, smoking, high body mass index, and high fasting plasma glucose.

Drug use is among the fastest growing risk factors for poor health in Australia, up 53 per cent between 1990 and 2013. Drug use is responsible for the biggest increase in poor health for men. The biggest increase in poor health for women comes from diabetes-related illness (high fasting blood glucose), increasing by 68 per cent since 1990.

However, it is not all bad news. Deaths from high cholesterol have decreased by 25 per cent, and deaths from diets low in fruit and vegetables have decreased by 10 per cent.

In Australia, increases in deaths due to high body mass index and diabetes-related illnesses have been increased 35 per cent and 47 per cent respectively. Australians are also grappling with poor kidney function and low physical activity, both of which are not among the top-10 global risk factors.

The leading risk factors associated with poor health in Australia in 2013 were high body mass index, smoking, and high blood pressure. While these were also in the top-five risk factors in 1990, smoking has decreased slightly, by 4 per cent.

Senior author on the study, University of Melbourne Professor Alan Lopez, said many of these risk factors for Australian deaths are preventable with lifestyle changes.

"While our study shows that public policy in Australia has been effective in reducing the health impacts of high cholesterol and insufficient fruit and vegetables in our diet, progress against some large, avoidable risks has been less impressive," Prof Lopez said.

"Smoking, high blood pressure and obesity are still prevalent among adult Australians and remain a large cause of disease burden. We can, and ought, to be more conscientious in reducing these exposures among all Australians, not only those considered at high risk."

Source: University of Melbourne