Alcohol and health outcomes: An umbrella review of meta-analyses base on prospective cohort studies

Alcohol and health outcomes: An umbrella review of meta-analyses base on prospective cohort studies
Umbrella review is becoming increasingly important for overviewing evidence of published systematic reviews and meta-analyses on a specific topic. Researchers in China performed what is thought to be the first umbrella review of meta-analyses to summarise the evidence of associations between alcohol consumption and health outcomes and to assess its credibility.
A systematic search and selection of eligible studies was conducted to identify meta-analyses of prospective cohort studies reporting the associations of alcohol consumption with health outcomes. The authors say that because primary studies were all based on prospective observational study, recall bias is reduced to a certain extent.
Alcohol consumption was categorised as low (defined as ethanol intake of >0 and ≤14.9 g/day), moderate (defined as intake of 15–29.9 g/day) and high (defined as intake of ≥30 g/day). Non-drinkers were taken as the reference group and random-effect models were used to recalculate the pooled relative risks and 95% CIs of different alcohol consumption levels.
Fifty-nine publications reporting 224 meta-analyses of prospective cohort studies with 140 unique health outcomes were included, in which there were 49 beneficial associations and 25 harmful associations with nominally statistically significant summary results. The quality of evidence was rated high only for seven beneficial associations (renal cell carcinoma risk, dementia risk, colorectal cancer mortality, and all-cause mortality in patients with hypertension for low alcohol consumption; renal cell carcinoma risk, cardiovascular disease (CVD) risk in patients with hypertension and all-cause mortality in patients with hypertension for moderate consumption) and four harmful associations (cutaneous basal cell carcinoma risk for low alcohol consumption; cutaneous basal cell carcinoma risk and cutaneous squamous cell carcinoma risk for moderate alcohol consumption; haemorrhagic stroke risk for high alcohol consumption).
In this umbrella review, only 11 health outcomes (5 in low alcohol consumption, 5 in moderate alcohol consumption and 1 in high alcohol consumption) with statistically significant showed high quality of epidemiologic evidence.
The researchers say that the limitations of the study are that, because only prospective meta-analyses were included, the results may have missed other health outcomes not yet studied through prospective meta-analysis. In addition, the effect of different types of alcoholic beverages were not explored.
More robust and larger prospective studies are needed to verify these results, the authors say.
Source: Zhong, Lixian et al. “Alcohol and Health Outcomes: An Umbrella Review of Meta-Analyses Base on Prospective Cohort Studies.” Frontiers in public health vol. 10 859947. 4 May. 2022, doi.org/10.3389/fpubh.2022.85994