Using data from the Global Burden of Disease project which spanned 25 years and 188 countries worldwide, the researchers wrote that there has been "a profound change" in risk factors associated with death since 1990.
In 1990 the biggest risk factors were child and maternal malnutrition, unsafe water, sanitation and handwashing – but these had now been replaced by dietary risks and high systolic blood pressure.
The study, led by the Institute for Health Metrics and Evaluation (IHME), identified 14 dietary risk factors, which included a diet low in fruit, vegetables, whole grain, nuts and fibre and a diet rich in red meat, processed food and sugar-sweetened beverages.
“At the global level, the most important contributors to the overall burden of diet are low fruit, high sodium, low whole grains, low vegetables, and low nuts and seeds," the authors wrote.
There were also some changes in the dietary risk factors since 1990, with high consumption of sugar sweetened beverages and red meat on the increase, while a diet high in trans fatty acids and a vitamin A deficiency saw more than a 10% fall as risk factors.
“In women, in nearly all countries in the Americas, north Africa, and the Middle East, and in many other high-income countries, high BMI is the leading risk factor,” wrote the researchers, with Canada, Guatemala, and Uruguay the only exceptions to this on the American continent.
A high BMI was also the leading risk in Spain, France, Switzerland and Belgium.
For men, high blood pressure was a leading risk factor in most of central and eastern Europe, south and east Asia, while in nearly all high-income countries and the Middle East it was either high blood pressure or tobacco use.
The authors identified high sodium intake as a key component of diet that was related to high blood pressure, and pointed to voluntary and mandatory reductions in sodium content of processed foods as a cost effective way to reduce intake.
“Even as the science on how far individuals should reduce their sodium consumption will continue to evolve, the argument for a population-level strategy to reduce sodium intake is compelling.”
In Russia the second biggest risk factor was alcohol.
The authors wrote that each of the risk factors included in their analysis was modifiable, pointing to great potential.
Lead author and IHME director, Christopher Murray, said: "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."
The authors examined 79 risk factors in total, including air pollution, sanitation, domestic violence, drug abuse and occupational hazards.
Source: The Lancet Journal
“Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013”
First published online 11 September 2015, doi.org/10.1016/S0140-6736(15)00128-2
Authors: C. J. Murray, A. D. Lopez et al.