《TAIPEI TIMES 焦點》 Genetic factor raises risk of strokes in local males

ALCOHOL PROBLEM: Researchers have identified ALDH2 deficiency as a risk factor for ischemic strokes in men, and more Taiwanese lack the enzyme than other people

By Lee I-chia / Staff reporter

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Men with inherited enzyme deficiency that is often demonstrated by the flushing of the skin after consumption of alcohol have a higher risk of ischemic strokes than people without it, a recent study by specialists at four Taiwanese hospitals suggests.

Alcohol-flushing response, which is due to a lack of aldehyde dehydrogenase 2 （ALDH2）, is a genetic mutation that affects a higher percentage of East Asians than other people, and Taiwanese most of all.

Researchers at Stanford University in California have found that while about 35 percent of Chinese, 30 percent of Japanese and 20 percent of Koreans have ALDH2 deficiency, Taiwan has the largest percentage of people without the alcohol-metabolizing ALDH2 gene, about 47 percent of the population.

A research team of physicians from Tri-Service General Hospital, National Taiwan University Hospital, Taipei Medical University Hospital and Taipei Medical University Shuang Ho Hospital, analyzed 914 patients who had suffered an ischemic stroke — a stroke caused by an obstruction in a blood vessel supplying blood to the brain — and 746 patients who had not had strokes, and identified ALDH2 deficiency as a risk factor for ischemic stroke in men.

The study found that men with ALDH2 deficiency have a 1.93 times the risk of ischemic strokes than people without it.

Sung Yueh-feng （宋岳峰）, an attending neurologist at Tri-Service General, said ALDH2 deficiency affects the body’s ability to metabolize alcohol, so a person with the deficiency might experience facial flushing, nausea, palpitations or vomiting after consuming alcohol.

While Taiwan has the highest population of people with ALDH2 deficiency in the world, about 6 percent of the nation’s population is homozygous for ALDH2*2, which means they are unable to metabolize alcohol at all, he said.

Research conducted at Stanford and Taipei Medical University Hospital has suggested that people with ALDH2 deficiency have a higher risk of developing head, neck and esophageal cancers, but the latest research by the four local hospitals suggests that homozygous ALDH2*2 is an independent risk factor for ischemic stroke in Taiwanese men, although not for women.

The different effects in men and women may be due ALDH2 activation by female sex hormones, but more studies are needed to confirm this assumption, Sung said.

He said while some medical facilities offer DNA testing to determine if a person has ALDH2 deficiency, for about NT$1,800 a test, but such testing is not necessary, because people, whether they have alcohol flushing response or not, should avoid excessive drinking.

People, especially men, with ALDH2 deficiency should reduce their alcohol consumption, avoid smoking, avoid food high in sugar, fat or sodium, and exercise regularly to prevent the “three highs” — high blood pressure, high blood lipids and high blood sugar, as well as other chronic disease that might contribute to a stroke, Sung said.

新聞來源：TAIPEI TIMES