(CNN) -- Chronic conditions such as heart disease and stroke have surpassed infectious diseases as the leading causes of deaths worldwide, according to a U.N. study released this week.
The U.N. study says chronic conditions like heart disease and stroke are the leading causes of death worldwide.
That is partly because of poorer diets in developing countries such as China and the fact that those with infectious diseases are living longer because of advanced treatments, according to health officials.
The United Nations' World Health Organization had predicted that cardiovascular disease would overtake infectious diseases as the most common cause of death, but not until 2010.
"Countries like China that once had a low-meat diet and thrived on wheat, corn and rice have increasingly become urbanized and developed," said Dr. Thomas Aversano, associate professor of cardiology at Johns Hopkins School of Medicine.
But the fact that people in countries like China are eating fattier foods as a result of a recent boom in Western fast-food outlets, Aversano said, doesn't mean the overall standard of living has worsened.
"If you look at a specific population at risk for coronary disease, like China, the mortality rate doesn't increase," he said. "We may be looking at an increase [in coronary disease] because other diseases have decreased."
In fact, mortality rates worldwide have decreased in the past 30 years as more people are living longer and the global population is growing, Aversano said.
The WHO report, released Monday, collected data based on 73 health indicators, including mortality levels and risk factors such as smoking and alcohol consumption.
It showed that other developing countries -- where diseases such as HIV/AIDS, tuberculosis and malaria are still prevalent -- are also seeing a rise in deaths attributed to chronic conditions, such as heart disease and stroke.
Aversano said the drop in mortality rates for such infectious diseases has opened the door for heart disease and stroke. But he also cautioned that increases in life expectancy, higher standards of living and poorer diets -- which have changed in the past several decades -- must also be taken into consideration.
Nearly 17 million people die every year from cardiovascular disease, according to WHO data. Another 20 million people survive heart attacks and strokes each year, and many must undergo costly clinical care, the WHO said.
Although chronic conditions have become the leading cause of death worldwide, Aversano stressed that coronary diseases are still highly treatable as medical therapies continue to advance.
But he also noted that promoting healthy diets, teaching teenagers about the risks of smoking, and warning adults about hypertension and diabetes can also lower the risk of coronary disease.
"The most important preventative strategy is education," he said.