Men who drink alcohol in any quantity have a risk of coronary heart disease that's at least a third lower than teetotalers, a large Spanish study confirmed.
Women who drink tend to have less risk, too, but the findings aren't so clear, according to an online report in the journal Heart.
Dr. Larraitz Arriola, of the public health department in San Sebastian, Spain, wrote that the risk of coronary heart disease, or CHD, actually decreases more as alcohol consumption increases.
Compared to men who don't imbibe at all, the risk of heart disease is reduced by 35 percent among light drinkers -- those who drink up to half a drink per day, on average -- and up to 50 percent in moderate-to-heavy drinkers -- those who consume anywhere from half a drink up to nine drinks daily.
Although similar trends appeared among women, the incidence of heart disease among them was too low to make any association with alcohol consumption statistically significant, Arriola and colleagues wrote.
The study did not examine other health effects of alcohol consumption. In the past, research has linked heavy alcohol consumption with liver disease, certain cancers and other ills.
Still, many studies have examined the association between alcohol use and CHD. Most have suggested that moderate intake reduces the risk, with positive effects on high-density lipoprotein cholesterol, clotting factors, insulin sensitivity, and inflammation providing biological plausibility for the observation.
However, scientists still debate whether 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 -- the notion that they tend to overload a population of nondrinkers with people who have other illnesses.
So Arriola and colleagues analyzed data from Spanish adults 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 study population included 15,630 men and 25,808 women aged 29 to 69 years, who provided information on a computerized questionnaire covering multiple aspects of diet and alcohol consumption, lifestyle, and medical history.
Over the next 10 years, researchers found that 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.
The researchers adjusted for factors including age, body mass index, physical activity, tobacco smoking, medications, and also for mediators including hypertension and diabetes. Among former drinkers, the risk of CHD was reduced about 10 percent.
The relationship between drinking and reduced risk of CHD was similar for all types of drinks, the investigators reported – although a bit less for wine than other types of alcohol.