In a recent study published in the Hypertension Journal, researchers performed a meta-analysis to determine the dose-response association between alcohol consumption and blood pressure (BP) levels.
Study: Alcohol Intake and Blood Pressure Levels: A Dose-Response Meta-Analysis of Nonexperimental Cohort Studies. Image Credit: New Africa/Shutterstock.com
Elevated BP is the most important modifiable risk factor for preventing cardiovascular diseases. Blood pressure levels are affected by genetic, environmental, and lifestyle factors such as alcohol intake, diet, physical activity, and body weight.
Alcohol intake may elevate BP; however, the relationship has not been extensively investigated, especially for low alcohol intake, and meta-analyses of data from non-experimental-type cohort studies are limited.
About the study
In the present meta-analysis of nonexperimental cohort studies, researchers evaluated the impact of alcohol consumption on BP.
Data were searched in the Embase and PubMed databases for longitudinal-type case-cohort or cohort studies, including healthy adult individuals, published in Italian or English before 9 May 2023 and documenting the relationship between alcohol consumption and BP.
The endpoints were the average differences with time in diastolic BP (DBP) and systolic BP (SBP), plotted based on baseline alcohol consumption by adopting a dosage-response one-stage approach.
Cross-sectional studies and those including individuals with cirrhosis, diabetes, or cardiovascular disease were excluded from the analysis. In addition, studies enrolling only alcoholics or only investigating binge drinking and the impact of acute alcohol intake were excluded.
Three researchers independently performed data screening, and disagreements were resolved by discussing or consulting two additional researchers.
Bias risks were evaluated using the Risk of Bias in Nonrandomized Studies-of Exposure (ROBINS-E) tool. Restricted maximum likelihood random-effects modeling and cubic spline modeling were performed for the analysis.
Subgroup analyses were stratified by region and sex, and sensitivity analyses were performed by excluding studies with data not adjusted for smoking status and body mass index (BMI).
Initially, 7,256 records were identified, from which 350 duplicates were removed, followed by the exclusion of 6,906 and 212 records following the title-abstract and full-text screening, respectively, and seven records, including 19,548 individuals (6,650 females and 12,701 males) followed for five years (median), were analyzed.
A significantly positive and linear association was observed between alcohol consumption at study initiation and DBP and SBP alterations over time, with no indication of any exposure-effect cut-off. The mean systolic BP was 1.3 and 4.9 mm of Hg greater for 12.0 or 48.0 grams of regular alcohol intake, respectively, compared to no intake.
For diastolic BP, corresponding differences of 1.1 and 3.1 mmHg, respectively, were observed. Subgroup analyses showed near-linear associations between alcohol consumption and systolic BP alterations among males and females and diastolic BP among males. In contrast, among females, the association showed an inverted U-shape.
Alcohol intake showed positive associations with BP alterations among North Americans and Asians, besides diastolic BP among North Americans.
The observation that the positive relationship between alcohol intake and blood pressure remained unaltered even after excluding studies without BMI and smoking status adjustments indicated that the findings were robust and did not result from inadequate data adjustments for primary confounding factors.
The strength of the relationship between alcohol intake and systolic BP alterations was lesser among females than in males, which might indicate causal roles of sex hormones or could have resulted from bias due to increased misclassification of the study exposure and outcomes among females consuming alcohol in large quantities.
The biological basis for varied patterns of the association between alcohol consumption and systolic and diastolic BP among Asians compared to North Americans could be related to known differences in alcohol metabolism enzymes, such as aldehyde dehydrogenase and alcohol dehydrogenase, between Asians and Western individuals.
However, the reasons for the impact of genetic backgrounds exclusively on diastolic BP and not systolic BP are unclear.
Overall, the study findings showed a direct and linear association between alcohol intake and systolic BP without evidence of a threshold for the relationship. In contrast, for diastolic BP, the association showed sex- and geography-based modifications.
Regular alcohol intake of 12.0 grams per day was related to a mean SBP difference compared to non-alcohol consumers of 1.3 mmHg, a change, on a population level, may have meaningful adverse impacts on cardiovascular morbidity.
Alcohol consumption, in any amount, should be considered a risk factor for high systolic BP, with important therapeutic and preventive implications.
Future meta-analyses must include more studies and investigate the relationship between alcohol intake and BP alterations by age and alcohol type, using validated questionnaires to assess alcohol intake to minimize heterogeneity in the estimates.