What this study adds
- Compared with abstinence, moderate alcohol intake is associated with increased risk of adverse brain outcomes and steeper cognitive decline in lexical fluency
- The hippocampus is particularly vulnerable, which has not been previously linked negatively with moderate alcohol use
- No protective effect was found for small amounts of alcohol over abstinence, and previous reports claiming a protective effect of light drinking might have been subject to confounding by associations between increased alcohol and higher social class or IQ
Alcohol use is a leading risk factor for disease burden worldwide, accounting for nearly 10% of global deaths among populations aged 15–49 years, and poses dire ramifications for future population health in the absence of policy action today. The widely held view of the health benefits of alcohol needs revising, particularly as improved methods and analyses continue to show how much alcohol use contributes to global death and disability. Our results show that the safest level of drinking is none. This level is in conflict with most health guidelines, which espouse health benefits associated with consuming up to two drinks per day. Alcohol use contributes to health loss from many causes and exacts its toll across the lifespan, particularly among men. Policies that focus on reducing population-level consumption will be most effective in reducing the health loss from alcohol use.
“We were able to find every single study ever published linking how much we drink with how long we lived,” said lead researcher Tim Stockwell, the director of the University of Victoria’s Centre for Addictions Research in British Columbia, Canada.
They found what they call an “abstainer bias” in most of the studies, meaning that when researchers compared moderate drinkers with non-drinkers, the non-drinking group often included people who don’t consume alcohol due to other health issues, such as former drinkers who stopped due to poor health. That bias may have made the moderate drinkers – those who downed anywhere from one drink per week to one or two drinks a day – seem healthier by comparison, Stockwell explained.
- 健康上の問題で禁酒している人を禁酒者グループに含めているという禁酒者バイアス（abstainer bias）がこれまでの研究に存在することがわかった。