More than one drink a day may raise high blood pressure risk in adults with Type 2 diabetes

"This is the first large study to specifically investigate the association of alcohol intake and hypertension among adults with Type 2 diabetes," said senior study author Matthew J. Singleton, M.D., M.B.E., M.H.S., M.Sc., chief electrophysiology fellow at Wake Forest University School of Medicine in Winston-Salem, North Carolina. "Previous studies have suggested that heavy alcohol consumption was associated with high blood pressure, however, the association of moderate alcohol consumption with high blood pressure was unclear."

Researchers examined the relationship between alcohol consumption and blood pressure in more than 10,000 adults with Type 2 diabetes (average age 63, 61% male). All were participants in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, one of the largest, long-term trials to compare different treatment approaches to reduce heart disease risk in adults with Type 2 diabetes, conducted from 2001-2005 at 77 centers across the U.S. and Canada.

All participants had Type 2 diabetes for an average of 10 years prior to enrolling in the study. In addition to 10 years with Type 2 diabetes, they were at increased risk for cardiovascular events because they had pre-existing cardiovascular disease; evidence of potential cardiovascular disease; or had at least two additional cardiovascular disease risk factors (such as high blood pressure, high cholesterol, smoking, or obesity).

In this study, alcohol consumption was categorized as none; light (1-7 drinks per week); moderate (8-14 drinks per week); and heavy (15 or more drinks per week). One alcoholic beverage was equivalent to a 12-ounce beer, 5-ounce glass of wine or 1.5 ounces of hard liquor. The number of drinks per week were self-reported by each participant via a questionnaire when they enrolled in the study.

Blood pressure was categorized according to the 2017 American College of Cardiology/American Heart Association Guideline for the Prevention, Detection, Evaluation and Management of High Blood Pressure in Adults as normal (below 120/80 mm Hg); elevated (120-129/<80 mm Hg); Stage 1 high blood pressure (130-139/80-89 mm Hg); or Stage 2 high blood pressure (140 mm Hg/90 mm Hg or higher). Most participants were already taking one or more blood pressure medications; therefore, the analysis of the blood pressure readings was adjusted to account for the effects of the medications and to estimate the underlying degree of high blood pressure.

Researchers found:

• light drinking was not associated with elevated blood pressure or either stage of high blood pressure;
• moderate drinking was associated with increased odds of elevated blood pressure by 79%; Stage 1 high blood pressure by 66%; and Stage 2 high blood pressure by 62%;
• heavy drinking was associated with increased odds of elevated blood pressure by 91%; Stage 1 high blood pressure by 149% (a 2.49-fold increase); and Stage 2 high blood pressure by 204% (a 3.04-fold increase); and
• the more alcohol consumed, the higher the risk and severity of high blood pressure.

"Though light to moderate alcohol consumption may have positive effects on cardiovascular health in the general adult population, both moderate and heavy alcohol consumption appear to be independently associated with higher odds of high blood pressure among those with Type 2 diabetes," Singleton said. "Lifestyle modification, including tempering alcohol consumption, may be considered in patients with Type 2 diabetes, particularly if they are having trouble controlling their blood pressure.

"People with Type 2 diabetes are at higher cardiovascular risk, and our findings indicate that alcohol consumption is associated with hypertension, so limited drinking is recommended," Singleton said.

The study has several limitations including the fact that alcohol consumption was based on a one-time questionnaire when participants enrolled in the study, therefore the results do not account for any changes in alcohol consumption over time. In addition, the study was not designed to assess if light alcohol consumption provided any benefits.

According to the American Heart Association, excessive drinking can increase the risk of high blood pressure, and people with Type 2 diabetes are already at increased risk for high blood pressure. For the general population, the association recommends alcoholic beverages be consumed in moderation, if at all, and drinkers should understand the potential effects on their health.