Alcohol and Risk for Heart Failure

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The summary below is from the full report titled "Alcohol Consumption and Risk for Congestive Heart Failure in the Framingham Heart Study." It is in the 5 February 2002 issue of Annals of Internal Medicine (volume 136, pages 181-191). The authors are CR Walsh, MG Larson, JC Evans, L Djousse, RC Ellison, RS Vasan, and D Levy.

What is the problem and what is known about it so far?

Drinking alcohol regularly and heavily for many years can weaken the muscle walls of the heart. The weakened muscles then stretch, which causes the heart to become larger. A large, weakened heart cannot pump blood through the body normally. Such symptoms as fatigue, shortness of breath, and leg swelling result. Doctors call this problem alcohol-related heart failure, or alcoholic cardiomyopathy. Drinking small to moderate amounts of alcohol, on the other hand, may help prevent heart attacks. Heart attacks occur when blood flow through the arteries to the heart (the coronary arteries) is blocked for a time long enough to damage or kill a portion of heart muscle. People who survive heart attacks may develop heart failure because of weakened or dead heart muscle. Thus, it is thought that drinking small to moderate amounts may indirectly prevent heart failure, but regular heavy drinking causes heart failure. Sorting out these tricky relationships between amounts of alcohol use and risk for heart failure is difficult.

Why did the researchers do this particular study?

To figure out the relationships between different amounts of drinking and risk for heart failure.

Who was studied?

Participants were 2796 men and 3493 women from Framingham, Massachusetts. None had coronary artery disease or heart failure at study entry.

How was the study done?

Every 2 to 4 years, the researchers asked participants about the number and type of drinks they had in a week. The researchers also regularly examined participants and reviewed their medical records to see whether they had heart attacks or heart failure. After 6 to 10 years of follow-up, the researchers looked for relationships between varied amounts of drinking and heart failure. They did special analyses to help ensure that observed relationships were not due to factors other than drinking. In these analyses, they "controlled for" age, weight, smoking, diabetes, high blood pressure, and high cholesterol level.

What did the researchers find?

Ninety-nine men and 120 women developed heart failure. In men, all reported levels of drinking (1 to 7 drinks per week, 8 to 14 per week, or more than 15 per week) were associated with lower risk of heart failure compared with no drinking. Men who reported 8 to 14 drinks per week seemed to have the lowest risk for heart failure. Among women, risk for heart failure was not clearly associated with drinking. Most people (about 70%) who developed heart failure did not have heart attacks.

What were the limitations of the study?

Drinking amounts were reported by the participants themselves, who may have underestimated how much they drink. Heart failure was assessed by using clinical examinations and medical record review rather than special tests that precisely measure heart function. Most patients were followed for less than 10 years; previous research suggests that heart failure due to continuous heavy drinking takes longer than that to develop.

What are the implications of the study?

Regular drinking of small, moderate, or heavy amounts of alcohol for 6 to 10 years does not increase risk for heart failure. In fact, drinking (including moderate and heavy drinking) may protect men from getting heart failure. However, patients should not base decisions about drinking solely on this study because drinking affects many organs other than the heart.