China is facing an epidemic of cardiovascular disease (CVD), such as heart attack and stroke, largely due to increases in high blood pressure and obesity, a study said Monday.

Decreasing physical activity, a high prevalence of smoking, and unhealthy diet have also contributed to the growing burden of CVD -- now the leading cause of death in China, according to the study published in the Journal of the American College of Cardiology.

"We described trends from 1991 to 2011 in dietary and other lifestyle risk factors for CVD in China and projected how these trends might play out from 2011 to 2031," said Yanping Li, research scientist in the Department of Nutrition at Harvard T.H. Chan School and lead author of the study.

"Our estimates suggest that the continued rise in high blood pressure, an increasingly sedentary lifestyle, increasing obesity, and worsening dietary trends will add millions of new cases of heart attacks and stroke over the next two decades."

The researchers analyzed data collected between 1991 and 2011 from 26,000 people living in nine Chinese provinces, as part of the China Health and Nutrition Survey.

They looked at dietary and lifestyle risk factors that have been previously linked with heart attack and stroke, and analyzed that data along with information on CVD-related disease and death incidence extracted from the China Health Statistical Yearbook and the National Population Census.

It showed that high blood pressure, high cholesterol, and high blood glucose accounted for most of the CVD disease burden in China in 2011.

That year, those three risk factors were associated, respectively, with 3.1, 1.4, and 0.9 million new cases of heart attack or stroke.

Of 6.8 million Chinese over age 35 who died in 2011, about 3 million of the deaths, or 44 percent, were CVD-related.

The researchers estimated that high blood pressure alone was responsible for roughly 40 percent of heart attacks or stroke.

High blood pressure has jumped dramatically in China over the past three decades. In 1979, its prevalence in the population was 7.7 percent; by 2010 it was 33.5 percent, comparable to that among U.S. adults.

The study also found that decreased physical activity during the study period was associated with a 0.7 million increase in CVD cases and increases of body mass index (BMI), a common measure of body fat based on weight and height, were associated with a 0.6 million increase.

Tobacco use was also associated with 1.3 million CVD-related cases, roughly a third of the CVD burden in men.

The researchers also noted that while Chinese eat more fiber, fruit, nuts, and omega-3 fatty acids, consumption of red meat and sugary beverages is increasing.

High sodium intake, which averaged 5.4 grams per day in 2011, was estimated to be responsible for one fifth of CVD cases in China.

"China is facing a rising epidemic of cardiovascular disease and it shows no sign of abating," said senior author Frank Hu, professor of nutrition and epidemiology at Harvard Chan School.

"It's imperative to continue to monitor the problem, which has serious social and economic consequences. Prevention of chronic diseases through promoting healthy diet and lifestyle should be elevated to a national public policy priority."