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Reducing alcohol consumption lowers blood pressure in heavy drinkers

 

This meta-analysis of randomised controlled trials examines the effects of alcohol reduction on blood pressure.

Bottom line

Reducing alcohol lowers blood pressure among men consuming between three and six drinks a day.

Reference

X Xin et al. Effects of alcohol reduction on blood pressure. Hypertension 2001 38: 1112-1117.

Search

The literature was searched using MEDLINE from 1966 to 1999. References from identified papers and review articles were also examined. Fifteen randomised control trials with a total of 2,234 participants were identified in which alcohol reduction was the only intervention difference between the comparison groups.

The trials, conducted between 1984 and 1996, varied in sample size from 10 to 909 participants. Men were the sole participants in 12 trials and the majority in the other three. Ages ranged from 27 to 57 years. Seven trials included only hypertensives, six included only normotensives and two included both. The study duration varied from one to 104 weeks with a median length of eight weeks. In eight trials a low-alcohol beer substitute was used to reduce alcohol intake; in seven trials cognitive-behavioural interventions were used. Average initial systolic and diastolic blood pressure ranged from 116 to 163 mm Hg and 62 to 98 mm Hg respectively.

Results

Self-reported reduction of alcohol consumption ranged from 16% to 100% with a median of 76%.

Overall, alcohol reduction was associated with changes in systolic and diastolic blood pressure of -3.31 mm Hg and -2.04 mm Hg respectively (95% confidence intervals -2.52 to -4.10 and -1.49 to -2.58).

These changes in blood pressure were not materially affected by excluding studies in which alcohol consumption was reduced by less than 30% (two studies, 770 participants); whose intervention period was less than four weeks (one study); or whose quality was classified as poor (two studies).

The results were also not significantly affected by differences between participants (e.g. whether hypertensive or normotensive) and study design characteristics (e.g. whether intervention was substitution or counselling).

A dose-response relationship was observed between alcohol reduction and blood pressure reduction (i.e. as alcohol consumption decreased, blood pressure decreased).

Comment

Among the strengths of this meta-analysis are the inclusion of randomised controlled trials; the consistency of results when studies of poor quality or with other limitations were excluded; and the observed dose-response relationship between alcohol reduction and blood pressure reduction.

One of its drawbacks is the small number of participants. Changes in blood pressure were found not to be significantly different between hypertensives and normotensives, between the two approaches used to reduce alcohol consumption, in trials lasting less than four weeks versus more than 12 weeks (and other participant and study characteristics). However, it is difficult to draw firm conclusions from these results due to the small sample sizes in these analyses.

This paper examined the effects of fairly heavy drinking; participants’ average initial alcohol consumption was three to six drinks a day. It was not able to examine the effects of moderate alcohol consumption. Finally, the majority of participants were men, but there is no reason to believe that the association between alcohol consumption and blood pressure would be different among women.