Alcohol consumption and hypertension: a collaborative study

Alcohol Health & Research World,  Summer, 1990  

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Investigators frequently have seen an association between the amount of alcohol consumed and blood pressure in diverse, world-wide populations. In a review of more than 30 cross-sectional epidemiologic studies, MacMahon (1987) stated that an overwhelming majority of the studies had reported significant elevations in blood pressure in individuals who consumed an average of at least three standard drinks (13 grams [g] to 14 g of ethanol per drink) per day when compared with non-drinkers. Among the risk factors for hypertension that have the potential to be modified, alcohol is second only to obesity in its observed contribution to the prevelence of hypertension in men. These findings have yet to be verified in women.

To investigate the relationship between alcohol intake and hypertension, the Department of Veterans Affairs (DVA), in collaboration with the National Heart, Lung, and Blood Institute (NHLBI) and the National Institute on Alcohol Abuse and Alcoholism (NIAAA), is conducting a prospective, randomized, multicenter clinical trial to determine whether blood pressure will lower during 6 months of alcohol moderation. This 5-year study began in 1989. The study participants will be nondependent heavy drinkers (those who average three drinks or more per day) with above average normal (80 mmHg to 89 mmHg) or mildly hypertensive (90 mmHg to 99 mmHg) diastolic blood pressure. [1] Another study objective is to determine whether the subjects' reduction in alcohol intake can be maintained for 2 years.

The alcohol reduction intervention design draws upon research conducted over the past 15 years (Sanchez-Craig et al. 1984; Sanchez-Craig 1987; Sanchez-Craig and Annis 1982; Marlatt 1985; and Miller and Munoz 1976). This research has resulted in the development of treatment models and has evaluated the outcome of cognitive interventions in heavy drinkers. The components of the interventions emphasize self-monitoring, self-control, and self-mastery. These characteristics are developed and enhanced by homework assignments, keeping behavior records, and practice outside the treatment setting. In each approach, patients learn to analyze their drinking patterns, determine alternatives to using drinking as a coping device, and develop methods of "self-soothing" or relaxation.

Several short-term, cross-over studies have provided further evidence that alcohol significantly affects hypertension (Howes 1985; Malhotra et al. 1985; Puddey et al. 1985; Potter and Beevers 1984). In these, researchers compared the blood pressures of individuals who had a low alcohol intake or who were abstinent with those of individuals who had a high alcohol intake over a period of time during which all subjects reduced their alcohol intakes. Average net reductions in blood pressure ranged from 3 mmHg (millimeters of mercury) to 13 mmHg for systolic blood pressure and from 1 mmHg to 6 mmHg for diastolic blood pressure. The range of alcohol-intake reduction was 3.5 to 6 drinks per day.

The results of these short-term intervention trials are encouraging. They suggest that hypertensive individuals who lower their alcohol intake may derive a therapeutic benefit and that normotensive individuals who do the same may derive a preventive benefit. However, these studies are based on small samples (10 to 48 subjects), and the followup periods examined were too short (3 days to 6 weeks) to allow definitive conclusions about the therapeutic and preventive effects of reducing one's alcohol intake.

The study being conducted jointly by the DVA, NHLBI, and NIAAA will attempt to correct these problems. It first will be instituted at four DVA medical centers and initially will assess both the effectiveness of recruitment into the study and the success of subjects' efforts to reduce alcohol intake. One hundred sixteen male veterans who meet the entry criteria described above will be randomized to either an alcohol reduction intervention group or a control observation group. If recruitment and the intervention technique prove to be successful, up to four additional centers will join the study. From all 8 centers, 464 additional participants will be recruited, bringing the total number of participants to 580.

Study participants randomized to the alcohol intervention program will receive six counseling sessions (60 to 90 minutes each) in the first 3 months of the study. They will receive further sessions at monthly intervals for the duration of the study phase (6 months). During the maintenance phase (18 months), they will receive counseling sessions at intervals of 1 to 3 months; in the sessions, investigators will review the subjects' progress and reinforce the techniques of alcohol-intake reduction. Gradually decreasing the frequency of the visits will permit study participants to gain control over their own lives and increase their self-confidence in mastering situation-specific behaviors that will occur from experiences outside the treatment setting.