Health experts in China are calling for what they say is long overdue: an effort to curb H-type hypertension by prescribing supplemental folic acid.

H-type hypertension is said to pose eight to 10 times the risk of a stroke due to an artery blockage to the brain compared with the non-H variety.

By reducing the incidence of the more dangerous type, 2.1 million cases of stroke could be averted annually, the experts say.

People with high blood pressure who have elevated levels of homocysteine, or Hcy, an amino acid, are defined as having H-type hypertension. China has roughly 200 million such patients out of a total 300 million people with high blood pressure, according to Huo Yong, director of the Department of Cardiology and Heart Center at Peking University First Hospital.

Researchers have found that a simple supplement - folic acid - can reduce a patient's Hcy level and thus help control blood pressure and prevent stroke.

Despite limited evidence of a direct cause-effect relationship between elevated Hcy and the occurrence of stroke, "correlation is confirmed in previous studies and the findings should be transformed into clinical practice to help with more targeted hypertension control and stroke prevention," Huo said.

In a study that began in 2008, those receiving both hypertension treatment and folic acid appear to have their stroke risk reduced by 21 percent compared with those who received the hypertension medication alone, according to Huo, who led the study.

It involved more than 20,000 Chinese hypertension patients and lasted four and a half years.

Xie Liangdi, deputy director of the First Hospital Affiliated to Fujian Medical University in Fuzhou, east Fujian province, said the findings were a breakthrough for hypertension intervention in China.

Chinese patients are at far higher risk of stroke compared with their counterparts in the West, Xie said.

Hypertension patients can go through Hcy screening and take folic acid as needed to prevent stroke and other complications, including kidney injuries, he added.

In response to a question about safety, Huo said taking folic acid without screening "should be OK".

Chinese people typically have lower levels of folic acid in general compared with Westerners and a "baby dosage" of folic acid, roughly 0.8 to 1 milligram per day, is fine for all.

In the US, Huo noted, it has been recommended since 1998 that people take supplemental folic acid. The incidence of stroke nationwide dropped substantially after 2002.

Huo urged Chinese health authorities to fully recognize and integrate that knowledge into clinical hypertension intervention policies.

shanjuan@chinadaily.com.cn