早上喝咖啡 小心心臟病

很多人喜歡在早上起床來一杯香醇的咖啡，讓一天有個清醒的開始。但是根據研究發現，這或許不是個好主意。請看下面來自路透社的報導。



Cup of coffee linked to heart attack in some

Tue Aug 22, 2006 6:35 PM BST

NEW YORK (Reuters Health) - That morning cup of coffee may be enough to trigger a first-time heart attack in vulnerable people, a study suggests.

Researchers found that among middle-aged and older adults, light to moderate coffee drinkers had an elevated risk of heart attack in the hour after having a cup of coffee.

This was particularly the case when a coffee drinker got little regular exercise or had three or more risk factors for heart disease -- such as diabetes(糖尿病), high blood pressure(高血壓) and smoking(抽煙).

On the other hand, there was no risk of having a heart attack among people who were heavy coffee drinkers, downing four or more cups per day. The difference, according to the researchers, may be that these coffee devotees(咖啡愛好者) build up a tolerance to the cardiovascular(侵襲心血管的) effects of caffeine.

The findings suggest that light or moderate coffee drinkers who are already at risk of heart attack should consider giving up the beverage, according to lead study author Dr. Ana Baylin.

For them, that morning cup could become "the straw that broke the camel's back,"(壓倒駱駝的最後一根稻草) Baylin, of Brown University in Providence, Rhode Island, said in a statement.

The findings, published in the journal Epidemiology(流行病學期刊), will likely add to the confusion that's been brewing about the health effects of coffee.

For example, a recent large study of U.S. adults found no association between heavy consumption of coffee -- at least the filtered kind -- and heart disease. But another study suggested that the heart effects of coffee might depend on genetics(遺傳學); researchers found an elevated heart attack risk only among coffee drinkers with a particular variant of a gene that helps metabolize caffeine.

The current study included 503 adults from Costa Rica who suffered a first heart attack between 1994 and 1998. Baylin and her colleagues questioned them about their coffee intake and overall diet in the hours and days before the heart attack. They also collected information on patients' medical history, background and lifestyle habits.



The researchers found that among those who typically drank less than one cup of coffee a day, the risk of heart attack in the hour after drinking a cup was four times higher than would be expected.

Similarly, moderate coffee drinkers -- those who had two or three cups per day -- showed a 60 percent higher-than-expected risk.

According to Baylin's team, that jolt of caffeine may boost nervous system activity and blood pressure enough to rupture a pre-existing fatty deposit(脂肪堆積), or plaque(血小板), on the artery walls(動脈內壁). When this happens, blood flow to the heart can be obstructed, causing a heart attack.

The researchers do acknowledge the limitations of their study, including the fact that patients were asked to recall their coffee intake in relation to the heart attack. In addition, it's well known that heart attack risk naturally rises in the morning, a time when most coffee drinkers have at least one cup.

However, Baylin and her colleagues note, that would not explain why heavy coffee drinkers seem immune to the effects. Instead, they suspect that heavy consumers develop a complete tolerance to the short-term cardiovascular effects of caffeine, whereas light to moderate drinkers remain susceptible.

SOURCE: Epidemiology, September 2006.



自由時報的中文編譯



早上喝咖啡 心臟病發機率高

〔編譯陳成良／路透紐約二十三日電〕美國一項最新研究警告，不常喝咖啡的中老年人，早上喝一杯咖啡就可能提高心臟病發的機率。

研究指出，平常不常喝咖啡又不常固定運動的中老年人，若同時又有三項或更多的心臟病風險因子，如糖尿病、高血壓和抽菸，更不適合一早就喝杯咖啡。不過，一天喝四杯咖啡以上的重度咖啡飲者，心臟病發機率提高與否就與喝咖啡無關。研究認為，這可能是後者已對咖啡因對心血管的影響有了一定容忍度。

主持這項研究的布朗大學貝林博士建議，已是心臟病危險群的中度或輕度咖啡飲者應考慮戒掉咖啡，因為喝咖啡可能成為「壓倒駱駝的最後一根稻草」。

貝林的研究小組以五○三名曾在一九九四至九八年首次心臟病發作的哥斯大黎加人為研究對象，調查他們心臟病發前數小時和數天的咖啡飲用量、飲食習慣、病史及生活習慣等背景資料，結果發現，平時一天喝不到一杯咖啡的人，早上喝一杯咖啡後一小時心臟病發機率比平常提高四倍；一天喝兩、三杯的中度飲者，早上一杯咖啡後的心臟病發機率也比平常增加六十％。

研究小組指出，咖啡因可能激化神經系統活動，血壓也升高到足以造成血管壁上累積的脂肪脫落，阻礙流向心臟的血液，造成心臟病發。不過報告也承認，他們的研究還不夠精確，包括是靠患者事後回憶咖啡飲用量，以及早上心臟病發機率本來就較高。

發表在「病理學」期刊的這項新研究，可能增加了有關喝咖啡與健康關係的爭論。最近美國一項大型研究便提出，成人喝咖啡與心臟病無關；另一項研究則指出，喝咖啡對心臟病的影響要看個人基因。