Dr. Gregory M. Marcus, from the Division of Cardiology at the University of California, San Francisco, and colleagues conducted an observational cohort study of differences in health outcomes based on alcohol sales laws by county in Texas.
All patients were residents of Texas, 21 years old or older, and were admitted to hospitals in Texas between 2005 and 2010. More than 1 million patients were included in the analysis.
Of the counties, 47 were wet (no restrictions on the sale of alcohol) and 29 were dry (prohibition of alcohol sales). Seven of them changed from dry to wet during the study period.
The main cardiovascular outcomes were atrial fibrillation, acute myocardial infarction, and congestive heart failure.
After multivariable adjustment, wet county residents had a greater prevalence (odds ratio 1.05, p=0.007) and incidence (HR 1.07, p=0.014) of atrial fibrillation.
Prevalence of myocardial infarction was lower (OR 0.83, p<0.001), as was its incidence (HR 0.91, p=0.019). Prevalence of congestive heart failure was also lower (OR 0.87, p<0.001).
In the seven dry counties that changed their status to wet, the post-conversion interval (from dry to wet county status) was associated with greater odds of hospitalization for atrial fibrillation (OR 1.07, p=0.001) and congestive heart failure (OR 1.07, p<0.001).
The researchers found no difference in acute myocardial infarction (OR 0.99, p=0.746).
"Cardiovascular disease is the most common cause of death worldwide, and alcohol is the most widely consumed drug in the United States," said Dr. Rory Brett Weiner, a cardiologist at Massachusetts General Hospital in Boston.
He said that studying the impact of alcohol intake on incident cardiovascular disease is important for its public health implications.
"Differences in laws affecting access to alcohol are associated with changes in health outcomes, both harmful and protective," said Dr. Marcus, "but the study's findings shouldn't be used to change any specific legislation."
Dr. Weiner agreed. "The study design minimizes confounders commonly seen in prior research that relied on self-report," he said, "but it still doesn't provide conclusive evidence with regard to the use of alcohol and incident cardiovascular disease."
Dr. Weiner said that the study did not contain information on the level of individual alcohol exposure, and therefore, the impact of the 'dose' of alcohol on cardiovascular outcomes could not be ascertained.
"Based on the question at hand -- the impact of alcohol -- it's unlikely that a randomized controlled study will ever be performed," he said, "so analyses like the current one are important."
According to Dr. Marcus, "We still don't understand the mechanisms underlying the relationship between alcohol and cardiovascular disease, and have a long way to go to achieve the sort of personalized medicine needed to figure out how to counsel an individual patient on their particular "prescribed" amount, if any, of alcohol."
The National Institute on Alcohol Abuse and Alcoholism supported this research. Dr. Marcus reported research support from Medtronic and Pfizer and equity interest in InCarda.