Rapid urbanization and a shift in lifestyles are the key factors behind a 20-year increase in heart disease among Chinese, according to a Harvard University study.

The study by the Harvard T.H. Chan School of Public Health suggests that major changes in Chinese society may have contributed to the surge in cardiovascular diseases, which can lead to heart attacks and stroke.

Also found were increases in high-cholesterol cases, obesity and Type 2 diabetes.

The study, published on Monday in the Journal of the American College of Cardiology, contends that an increasing body mass index, lower physical activity, smoking and unhealthy diets have contributed to the rise in cardiovascular disease, the No 1 cause of death in China.

Tobacco use is falling in China, but 53.4 percent of the nation's men still smoke. In 2011, tobacco use was connected to 1.3 million cases of cardiovascular disease, the study found.

Low-grade cigarettes can be had for 3 yuan (49 cents) a pack in China, the world's largest cigarette market. China has 300 million smokers; the US has an estimated 60 million.

In 2015, Beijing city authorities passed anti-smoking legislation banning smoking in all indoor public places, workplaces and on public transportation.

The study's authors also noted that while the Chinese diet has improved in some areas－with more fiber, fruit, nuts and omega-3 fatty acids－the consumption of red meat and sugary beverages is growing.

High salt intake－which averaged 5.4 grams daily in 2011－was blamed for 20 percent of cardiovascular disease cases in China.

The increases in hypertension and BMI were more prevalent among younger people and rural residents, the authors said.

"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," said Yanping Li, research scientist in the Department of Nutrition at Harvard Chan School and the study's lead author.

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

They looked at 17 dietary and lifestyle risk factors, including high systolic blood pressure, high cholesterol, high blood sugar, high BMI, low physical activity and smoking, along with 11 dietary factors, and analyzed data from the China Health Statistical Yearbook and the National Population Census.

The study found that high blood pressure, high cholesterol and high blood glucose accounted for most cardiovascular disease cases in China in 2011. The three risk factors were associated with 3.1 million, 1.4 million and 0.9 million new cases, respectively, of heart attack or stroke.

Of the 6.8 million Chinese over age 35 who died in 2011, about 3 million－44 percent－were related to cardiovascular disease.

The researchers contend that high blood pressure was responsible for roughly 40 percent of heart attacks or stroke. In 1979, high blood pressure, or hypertension, was found in 7.7 percent of the population; by 2010, it was 33.5 percent－comparable to the rate among US adults.

"Prevention of chronic diseases through promoting healthy diet and lifestyle should be elevated to a national public policy priority," said senior author Frank Hu, professor of nutrition and epidemiology.