The effect of reduced alcohol consumption on blood pressure: a randomised, controlled, single blind study.

A randomised, controlled, single blind trial was conducted in office workers with mild hypertension (systolic blood pressure (SBP) 140 to 180 mmHg, diastolic blood pressure (DBP) 90 to 110 mmHg) to determine the effect of decreasing alcohol consumption. After a baseline examination, 50 male volunteers aged 30 to 59 were randomised to two groups. Group A were told to abstain from or reduce alcohol consumption for two weeks, while group B were instructed to maintain their usual alcohol consumption. Complete records were obtained on 49 subjects. The daily alcohol consumption of groups A and B at baseline was similar, i.e. 71.9 ml and 72.5 ml of ethanol, respectively, and changed to 16.1 ml and 62.9 ml, respectively, during the experiment. After two weeks, group A were asked to resume their normal consumption whilst group B were asked to reduce or abstain (phase II). However in view of a treatment period interaction, statistical analysis was confined to phase I. During phase I, group A, whose alcohol consumption had reduced, showed decreases of 5.8 and 7.1 mmHg in SBP during the the first and second weeks, respectively. In group B, these decreases were only 0.6 and 1.9 mmHg, respectively. The difference between the falls in SBP in groups A and B was significant (P = 0.005) as judged by analysis of variance. The DBP also decreased, but there was no significant difference between the decreases in the two groups. Changes in gamma-glutamyl-transpeptidase, a biochemical marker of alcohol consumption, from the initial values to the end of phase I were significantly different in groups A and B.(ABSTRACT TRUNCATED AT 250 WORDS)