This population-based study revealed a significant association between drinking patterns and blood pressure among non-hypertensive current drinkers. Total drinking volume is associated with SBP in a linear manner in both men and women, which indicates that alcohol consumption may be associated with prehypertension risk.
The alcohol-blood pressure associations appear to be different by gender. Higher drinking quantity and frequency of binge drinking were associated with higher blood pressure in men but not in women. This differential association may be related to the fact that male drinkers usually drank more frequently with a higher quantity and had more binge drinking episodes. Therefore, the adverse effects become more manifest in male drinkers. This can explain why a higher proportion of diagnosed high blood pressure in men is attributable to alcohol consumption than in women.20
In previous studies, when non-drinkers were used as the reference group,16
a J-shaped alcohol-hypertension association among women and a linear association among men was frequently reported. However, our results do not support the notion that “light-to-moderate alcohol consumption decreased hypertension risk in women and increased risk in men”.16
The use of non-drinkers as the referent groups has been problematic. When examining alcohol-blood pressure association among current drinkers, we observed that a threshold beyond which alcohol consumption begins to become harmful does not appear to exist.
Although only half of male current drinkers who were not hypertensive reported alcohol consumption that exceeded the Drinking Guidelines, about half of this population (52%) already manifested prehypertension. Data from 2005–2006 NHANES estimated that 1 out of 4 persons aged 20 years or older in US has prehypertension.21
Some studies showed that alcohol consumption predicts prehypertension,22
and progression from prehypertension to hypertension.23
Randomized controlled trials show that reducing alcohol consumption lowers blood pressure in both non-hypertensive, and treated and untreated hypertensive subjects.26
Xin et al reported a 76% reduction in alcohol consumption was associated with decreasing blood pressure, and this relationship is dose-dependent.29
Questions remain as to whether the limit for sensible drinking (not to exceed two drinks on days when drinking) for males is really safe. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure actually recommended men of smaller body size to consume “no more than 0.5 oz of ethanol (one drink) per day”.30
In light of the risk of developing high blood pressure, it may be wise to advise all male drinkers to consume no more than one drink per day. However, it is still unclear whether an intervention to lower alcohol intake in moderate to heavy drinkers with above optimal to slightly elevated diastolic blood pressure could produce sustained reduction of blood pressure.31
In our study, drinking quantity, frequency of binge drinking, and drinking frequency were all related to the health outcome of our concern. In addition, risk and frequency of binge drinking increased with frequency of drinking.32
Therefore, researchers have recommended that drinking patterns should be taken into account in making drinking guidelines. For example, the National Institute on Alcohol Abuse and Alcoholism (NIAAA) Physicians’ Guidelines incorporating both daily and weekly alcohol limits performed better in the prediction of a variety of alcohol-related outcomes than the US Dietary Guidelines.33
Our study revealed a dose dependent relationship between alcohol consumption and higher average blood pressure among non-hypertensives. In addition, the associations of drinking patterns with the prevalence of prehypertension were gender-related. Our findings added to the large body of evidence that alcohol consumption is harmful. Preventive counseling for alcohol use should be integrated in primary care. Limits for sensible drinking need to be revisited with more epidemiologic data using robust analytic methods. More intervention studies are needed to examine the extent of the reduction in alcohol intake to produce significant reduction in blood pressure levels among drinkers.