Systematic review of the effect of daily alcohol intake on blood pressure.

Numerous epidemiologic investigations have found an association between moderate intake of alcohol and increased blood pressure (BP). However, in controlled clinical studies that directly tested the effects of alcohol intake on BP, findings are inconsistent, perhaps because of differences in duration of alcohol use and the timing of BP measurements. In this setting, we performed a systematic review of trials that measured BP after a period of sustained alcohol intake (defined as daily intake of at least one alcoholic drink daily) in one group and that also had a control group of individuals who consumed no alcohol. Nine studies met the entrance criteria. The review demonstrated a significant rise in systolic blood pressure (SBP) and diastolic BP (DBP) of 2.7 mm and 1.4 mm Hg, respectively, after alcohol intake. An early effect of alcohol leading to a reduction BP (in the hours after exposure) and a later effect (next day) of raising BP led to smaller differences in the net effect of alcohol on BP when ambulatory BP monitoring measurements were compared with casual office- or clinic-based measurements. Our findings may have important implications for interpreting studies measuring the effect of alcohol on BP as well as for regular clinical care. These findings indicate that the timing of BP measurements after alcohol intake has a substantial effect on the magnitude and perhaps even the direction of BP change.