Alcohol Cuts CHD Risk in Men

Reporting online in Heart, Larraitz Arriola, PhD, of the public health department in San Sebastian, Spain, and colleagues wrote that a multivariate analysis determined the following reductions of CHD risk at these consumption levels:

• Low levels of alcohol (0 to 5 mg/day), HR 0.65 (95% CI 0.41 to 1.04)
• Moderate levels (5 to 30 g/day), HR 0.49 (95% CI 0.32 to 0.75)
• High levels (30 to 90 g/day), HR 0.46 (95% CI 0.30 to 0.71)
• Very high levels (more than 90 g/day), HR 0.50 (95% CI 0.29 to 0.85)

Many studies have examined the association between alcohol use and CHD. Most have suggested that moderate intake reduces the risk, with effects on high-density lipoprotein cholesterol, clotting factors, insulin sensitivity, and inflammation providing biologic plausibility for the observation.

However, scientists still debate whether the the association is truly causal, and whether the studies have been marred by "abstainer error."

Abstainer error refers to classification of participants who had recently stopped drinking -- usually because of declining health, frailty, or disability -- as nondrinkers. This has also been referred to as the "sick quitters" hypothesis.

So Arriola and colleagues analyzed data from the Spanish cohort in the European Prospective Investigation into Cancer, categorizing never-drinkers separately from former drinkers, and analyzing men and women separately because of differences in CHD risk profiles and alcohol metabolism.

Their cohort included 15,630 men and 25,808 women ages 29 to 69 years, who provided information on a computerized questionnaire covering multiple aspects of diet and alcohol consumption, lifestyle, and medical history.

During a median follow-up of 10 years, there were 481 coronary events in men and 128 in women, giving crude CHD incidence rates of 300.56 per 100,000 person-years for men and 47.93 per 100,000 person-years for women.

Multivariate analyses adjusted for multiple confounders including age, body mass index, physical activity, tobacco smoking, medications, and also for mediators including hypertension and diabetes.

Among men, the adjusted hazard ratio for former drinkers was 0.90 (95% CI 0.56 to 1.44).

"The baseline characteristics of former drinkers were completely different -- they reported more hypertension, more diabetes, were slightly older, and reported more consumption of antithrombotics and cardiovascular medications," the investigators wrote.

These differences support the decision to remove the former drinkers from the reference category of never-drinkers, because it was not the absence of alcohol that was elevating their CHD risk, but their overall poorer health.

Among women, alcohol consumption tended to be associated with a lower CHD risk, but the results were not statistically significant and investigators pointed out that the 95% confidence intervals all included unity. Here are the women's results:

• Former drinkers, adjusted HR 1.17 (95% CI 0.66 to 2.08)
• Low consumers, adjusted HR 0.75 (95% CI 0.48 to 1.17)
• Moderate consumers, adjusted HR 0.62 (95% CI 0.36 to 1.07)
• High consumers, adjusted HR 0.21 (95% CI 0.03 to 1.52)

The lack of significant association in women was probably due to the low number of CHD events they experienced, according to the investigators.

The inverse relationship between alcohol use and CHD risk was similar for all types of drinks. Although the association was weaker in the multivariate analysis for wine consumption, it remained significant at higher levels.

The authors concluded that their study confirms a negative association between alcohol intake and CHD in men.

"We can also state, although with caution, that our study is free of the so called 'abstainer error' and that residual confounding does not influence the results obtained to any significant degree."

Explain to interested patients that this study indicates that alcohol consumption is associated with a lower risk of heart disease in men, but the association remains uncertain in women.

Arriola L, et al "Alcohol intake and the risk of coronary heart disease in the Spanish EPIC cohort study" Heart 2009; DOI: 10.1136/hrt.2009.173419.