Preventing, controlling hypertension could reduce China's high stroke rate

While in the United States heart disease is the leading cause of death, in China it is stroke. People have speculated for years about why the Chinese are predisposed to stroke to a greater extent than heart disease. Some have believed that there is a genetic predisposition, and others have thought that environmental factors might be responsible.

A new study by Yale investigators has proposed, however, that a difference in the prevalence of risk factors might account for the disparity between frequency of stroke and heart disease in China versus the U.S.

Researchers know that hypertension has a stronger relationship to stroke, while cholesterol is more strongly associated with heart disease. Given this knowledge, the Yale investigators found what they expected in the data: China and the United States had different cardiovascular risk factor profiles, with hypertension being more common in the United States, but China having higher blood pressure levels due to more people not being treated or being inadequately treated.

"Although China does not yet have as high a prevalence of hypertension as the United States, because of under-treatment and poor control, the percentage of Chinese people with high blood pressure in the population is worse. The poor treatment of hypertension is likely responsible for China's higher stroke prevalence," said Harlan M. Krumholz, Yale cardiologist and senior author on the study.

Therefore, the key to addressing the leading cause of death in China may lie in the detection and effective treatment of this risk factor, said the researchers. "You do not need to go beyond the risk factor profile to explain the high risk of stroke," said Yale research scientist Yuan Lu, the first author. "What is unfortunate is not that hypertension levels are higher in China compared with the United States, but that the treatment for hypertension in China is inadequate. Fortunately, with this new insight comes a great opportunity to reduce the burden in stroke in the country."