In the first study looking at cessation of alcohol consumption and atrial fibrillation (AF) risk, UC San Francisco researchers have shown that the longer people abstain from drinking alcohol, the lower their risk of AF.
After adjusting for potential variables, the researchers found that every decade of abstinence from alcohol was associated with an approximately 20 percent lower rate of AF, regardless of the type of alcohol consumed, such as beer, wine or liquor.
Their study appears online Oct. 18 in PLOS ONE.
“For a disease that affects millions and is one of the most important causes of stroke, identifying modifiable risk factors is especially important,” said senior author Gregory Marcus, MD, MAS, a UCSF Health cardiologist and director of clinical research in the UCSF Division of Cardiology. “Future research may help identify patients particularly prone to alcohol-related AF, and, when done, targeted counseling to those patients may be especially effective.”
In AF, electrical impulses in the upper chambers of the heart are chaotic, and the atrial walls quiver, rather than contracting normally in moving blood to the lower chambers. As a result, blood clots may form, leading to stroke or heart attacks. One in four adults over age 40 is at risk for AF, with a projection of nearly 6 million people in the nation having the condition by 2050.
Despite the popular notion that moderate alcohol use reduces the risk of heart disease, several recent studies have found an association between heavy alcohol consumption – usually defined as more than three drinks per day – and AF, while a 2011 meta-analysis of 14 studies also found a relationship between any level of alcohol consumption and AF.
In the PLOS ONE study, Marcus and his colleagues analyzed data generated over 25 years through the Atherosclerosis Risk in Communities (ARIC) Study. Designed to identify risk factors for atherosclerosis and cardiovascular disease, ARIC recruited 15,792 adults ages 45-64 between 1987-89 in Forsyth County, N.C., Jackson, Miss., Minneapolis suburbs and Washington County, Md. After a comprehensive baseline assessment, participants had four follow-up visits in 1990-92, 1993-95, 1996-98 and 2011-13 and were contacted annually by phone to obtain information about hospital admissions and vital status.
The PLOS ONE study assessed data on 15,222 ARIC participants who were asked whether they currently consumed alcoholic beverages, and, if not, whether they had in the past. For those citing past drinking, follow-up questions included number of years since the individual stopped drinking, number of years he/she drank, types of alcoholic beverages consumed and usual number of drinks per week before stopping.
At baseline, 3,790 (25 percent) participants reported being “never drinkers,” 8,546 (56 percent) said they were current drinkers and 2,886 (19 percent) former drinkers.
Using electrocardiograms (ECGs), hospital discharge codes and death certificates over a median follow up of 19.7 years, researchers found 1,631 cases of atrial fibrillation, of which 370 occurred in former drinkers. Past drinkers had an increased risk of developing AF. Those who did not develop AF quit longer ago, drank for a shorter period of time and consumed less alcohol in the past.
The researchers found that former drinkers were more likely than either current or “never” drinkers to have a lower education level, be former or current smokers, and have diabetes, coronary artery disease and heart failure.
After adjusting for these and other variables, the researchers found that every additional decade in which alcohol was consumed in the past was associated with a 13 percent higher rate of AF, and every additional drink per day during former drinking was associated with a 4 percent higher rate. Analysis of alcohol type consumed in the past or present showed no associations with AF.
“The number of years of drinking and the amount of alcohol consumed may confer an increased risk of AF, even when abstinence is later practiced,” said Marcus, holder of the Endowed Professorship of AF Research in the UCSF School of Medicine. “Our finding suggests there may be chronic cardiac remodeling effects from alcohol that don’t rely on alcohol as an acute trigger, and further research into why this occurs is needed.”
Among the study limitations, researchers said the study used self-reporting data that may not be fully accurate, and AF totals may be underestimated, given that diagnosis relied on hospital discharge records, death certificates and ECGs. There also was no data on why participants quit drinking, which could help explain the higher AF risk among former drinkers.
Other contributors to the PLOS ONE study were lead author Shalini Dixit, internal medicine resident, and Eric Vittinghoff, PhD, MPH, professor of epidemiology and biostatistics, UCSF; Alvaro Alonso, PhD, MD, MPH, Emory University Rollins School of Public Health; Elsayed Soliman, MD, Wake Forest University School of Medicine; and Lin Chen, MD, University of Minnesota Medical School.
Financial support was provided by the National Institutes of Health (NIH) National Center for Advancing Translational Sciences through UCSF Clinical & Translational Science Institute grant TL1 TR000144; NIH National Institute on Alcohol Abuse and Alcoholism grant R01AA022222; American Heart Association grant 16EIA26410001; Doris Duke Charitable Foundation; and National Heart, Lung, and Blood Institute contracts HHSN268201100005C, HHSN268201100006C, HHSN268201100007C, HHSN268201100008C, HHSN268201100009C, HHSN268201100010C, HHSN268201100011C and HHSN268201100012C.
UC San Francisco (UCSF) is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes top-ranked graduate schools of dentistry, medicine, nursing and pharmacy; a graduate division with nationally renowned programs in basic, biomedical, translational and population sciences; and a preeminent biomedical research enterprise. It also includes UCSF Health, which comprises three top-ranked hospitals, UCSF Medical Center and UCSF Benioff Children’s Hospitals in San Francisco and Oakland, and other partner and affiliated hospitals and healthcare providers throughout the Bay Area.