Moderate alcohol consumption was associated with a lower risk of several cardiovascular diseases compared with not drinking and heavy drinking, according to a population-based cohort study in the United Kingdom.

The researchers found that compared with moderate drinking, non-drinking was associated with an increased risk of unstable angina, MI, unheralded coronary death, heart failure, ischemic stroke, peripheral arterial disease and abdominal aortic aneurysm.

Meanwhile, compared with moderate drinking, heavy drinking was associated with an increased risk of unheralded coronary death, heart failure, cardiac arrest, transient ischemic attack, ischemic stroke, intracerebral haemorrhage and peripheral arterial disease.

However, moderate drinking was associated with an increased risk of MI and stable angina when compared with heavy drinking.

Lead researcher Steven Bell, PhD, of Cambridge University and University College London, and colleagues published their results online in the BMJ on March 23.

The researchers examined electronic health records on more than 1.9 million patients who were at least 30 years old from Jan. 1, 1997, to March 25, 2010, and enrolled in the CALIBER program. None of the patients had cardiovascular disease at baseline.

The patients self-reported their alcohol consumption, and general practitioners or practice nurses prospectively collected and coded the data. They used the most recent record of alcohol consumption in the five years before patients enrolled in the study.

The researchers defined moderate drinking as three units per day or 21 units per week for males and two units per day or 14 units per week for females. They said that one unit of alcohol is approximately half a pint of ordinary strength beer or a 25 mL of spirits.

During a median follow-up period of six years, 114,859 patients had an incident cardiovascular diagnosis.

A multivariable Cox analysis found that compared with moderate drinking, non-drinking was associated with a 33 percent increased risk of unstable angina, a 32 percent increased risk of MI, a 56 percent increased risk of unheralded coronary death, a 24 percent increased risk of heart failure, a 12 percent increased risk of ischemic stroke, a 22 percent increased risk of peripheral arterial disease and a 32 percent increased risk of abdominal aortic aneurysm as their initial presentation of cardiovascular disease.

In addition, compared with moderate drinkers, heavy drinkers had a 21 percent increased risk of unheralded coronary death, a 22 percent increased risk of heart failure, a 50 percent increased risk of cardiac arrest/sudden coronary death and an 11 percent increased risk of transient ischemic attack as their initial presentation of cardiovascular disease. Heavy drinkers also had a 12 percent lower risk of MI and a 7 percent lower risk of stable angina as their first cardiovascular disease.

The researchers acknowledged the study had a few limitations, including that they relied on self-reported alcohol intake and decided how to best combine the recorded codes. They also did not have standard questions to assess drinking during the study. In addition, they could not account for differences in risk by beverage type, the impact of drinking patterns or the changes in drinking over time on cardiovascular outcomes. Further, the study’s observational design meant that the researchers could not determine causal relationships. 

“Our findings, from the most comprehensive study to date of the relation between alcohol consumption and risk of cardiovascular disease, indicate that moderate alcohol consumption is associated with a lower risk of initially presenting with several, but not all, cardiovascular diseases,” the researchers wrote. “Similarly, we show that heavy drinking is differentially associated with a range of such diseases. This has implications for patient counseling, public health communication, and disease prediction algorithms and suggests the necessity for a more nuanced approach to the role of alcohol consumption in the prevention of cardiovascular disease.”