LOS ANGELES, CA (Catholic Online) - As a sign of the growing international problem of obesity, high body mass index was the biggest "climber," moving from tenth place in 1990 to sixth in 2010. More than three million deaths were attributable to excess body weight, more than three times as many as under-nutrition.

In both Australasia and southern Latin America, high BMI ranked as the leading risk factor.

As published in the medical journal The Lancet, an international consortium of scientists studied various risk factors as part of the Global Burden of Disease Study 2010.

"Overall we're seeing a growing burden of risk factors that lead to chronic diseases in adults, such as cancer, heart disease and diabetes, and a decreasing burden for risks associated with infectious diseases in children," Professor Majid Ezzati, of Imperial College London said:

"But this global picture disguises the starkly different trends across regions.

"The risks associated with poverty have come down in most places, like Asia and Latin America, but they remain the leading issues in sub-Saharan Africa."

The number of deaths attributed to each risk factor and disability-adjusted life years, or DALYs, a unit that takes into account both years of life lost and years lived with disability.

"We looked at risk factors for which good data are available on how many people are exposed to the risks and how strong their effects are, so that our results can inform policy and programmatic choices," Professor Stephen Lim, of the University of Washington, said.

Smoking, including second-hand smoke, was the risk factor with the biggest burden in western Europe and high-income North American countries, and accounted for 6.3 million deaths worldwide in 2010.

Dietary risk factors and physical inactivity collectively accounted for one tenth of DALYs in 2010, with the most prominent dietary risks being too much salt and not enough fruit.

"The good news is there are lots of things we can do to reduce disease risk," Professor Ezzati says.

"To bring down the burden of high blood pressure, we need to regulate the salt content of food, provide easier access to fresh fruits and vegetables, and strengthen primary healthcare services.

"Under-nutrition has come down in the ranking because we've made a lot of progress in many parts of the world.

"This should encourage us to continue those efforts and to replicate that success in Africa, where it's still a major problem."