A new global study has identified high blood pressure, smoking and high body mass index as the top three avoidable risk factors for death and disease among adults worldwide. Among children under 5, undernutrition remains the leading avoidable risk factor.

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The number of deaths attributable to high blood pressure increased by almost 50% between 1990 and 2013, according to the study results.

Study leader Dr. Mohammad Hossein Forouzanfar, of the Institute for Health and Metrics Evaluation (IHME) at the University of Washington in Seattle, and colleagues publish their findings in The Lancet.

The team analyzed 1990-2013 data from the Global Burden of Disease, Injuries and Risk Factor (GBD) study.

For the new study, they set out to estimate the number of deaths, years of life lost, years lived with disability and disability-adjusted life years that were attributable to 79 modifiable risk factors across 188 countries over the 23-year period.

The researchers also assessed the effects of these avoidable risk factors by age and sex.

In total, the modifiable risk factors assessed accounted for 30.8 million deaths in 2013, increasing from 25.1 million in 1990.

The team found that high blood pressure, or hypertension, was the greatest mortality risk factor for both men and women. The number of deaths attributable to high blood pressure increased by almost 50% between 1990 and 2013, according to the results.

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However, high blood pressure was found to be a greater burden for men than women. Over the study period, the number of deaths attributable to the condition rose by 59% among men, compared with 39.9% among women. In 2013, high blood pressure was linked to the death of 5.4 million American men.

Smoking was found to have the second greatest impact on mortality for both men and women over the 23-year period, with the number of deaths attributable to the habit increasing by more than 25%. Again, smoking was found to be a greater burden for men than women, contributing to 4.4 million deaths for men in 2013 and 1.4 million deaths among women.

High body mass index (BMI) was the third greatest mortality risk factor for men and women, with the team identifying a 63.2% increase in deaths due to the condition between 1990 and 2013. Contrary to the effects of hypertension and smoking, however, high BMI appeared to be a greater burden for women than men.

The researchers found high blood pressure, high BMI and smoking were also the leading risk factors for disability-adjusted life years, or loss of healthy life, in 2013 for both men and women.

On assessing the effects of dietary risk factors on mortality, the team found a combination of 14 of these risk factors contributed to 21% of total global deaths between 1990 and 2013 through conditions such as heart disease and diabetes. These risk factors included diets low in fruits and vegetables and diets high in red meat and sugary drinks.

While the researchers note that child undernutrition – defined as children who are underweight, have stunted growth or muscle wasting due to lack of nutrition – fell out of the top 10 global mortality risk factors over the study period, it still remains the leading cause of death for children under the age of 5.

According to the results, 1.3 million deaths among under-5s were attributable to child undernutrition in 2013, accounting for 21.1% of all deaths in that age group. The countries where this was most prominent included Chad, South Sudan, Democratic Republic of the Congo, Somalia and Niger.

“While we have seen a tremendous growth in risk factors that contribute to noncommunicable diseases like heart disease, pulmonary diseases and diabetes, childhood undernutrition remains a huge challenge for some countries,” notes Dr. Forouzanfar.

Assessing the greatest modifiable risk factors country by country, the team noticed some significant variations. In South and Southeast Asia, for example, household pollution was found to be the leading mortality risk factor, while smoking was the leading mortality risk factor in the UK and many other high-income countries.

The most prominent differences were found in sub-Saharan Africa, where child undernutrition, alcohol use, unsafe water and sanitation and unsafe sex were identified as the leading causes of death.

The researchers note that unsafe sex still poses a huge risk for global health, with the study revealing that it contributed to 82.3% of global deaths from HIV/AIDS in 2013, most of which occurred in South Africa.

Dr. Forouzanfar and colleagues say their results provide a “clear indication” of where governments around the globe should focus their risk factor prevention programs.

Study co-author Dr. Christopher Murray, director of IHME, adds:

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

In June, Medical News Today reported on another study published in The Lancet in which researchers found that 95% of the world’s population has at least one health problem.