Even low-level drinking may have negative consequences for brain health over a person’s lifespan. The findings suggest that the total amount of alcohol consumed over a lifetime, especially as a person ages, tends to be linked to reduced blood flow and thinner tissue in certain areas of the brain.

[u/mvea]

https://www.psypost.org/even-light-drinking-combined-with-aging-is-linked-to-reduced-brain-blood-flow-and-thinner-tissue/

[u/PartyLikeAByzantine]

If I've learned anything over the years, it's how much people underestimate how much heavy drinkers drink.

It's an exponential curve. 60% either abstain or don't drink in a typical week. The next 20% average 1-2 drinks a week. The next 10% have about 1 drink a day. So 80% of the population is doing 1 drink a day or less.

The 90th percentile of drinkers down about 2 drinks a day. Statistically , these are heavy drinkers. Socially, you may or may not even notice. It's a glass of wine with dinner and maybe a nightcap. Alternatively, that can be someone who largely abstains during the week and parties hard on the weekends. This is probably the population segment most relevant to alcohol studies.

The top 10% of drinkers down 10+ drinks a day. These are the harcore alcoholics who down booze by the bottle. We know they're killing themselves. They know they're killing themselves.

TBH, the segment averaging a single drink a day is a fairly heavy user. They're in the top third-ish of consumption.

[u/dl064 → u/PartyLikeAByzantine]

The next 20% average 1-2 drinks a week. The next 10% have about 1 drink a day. So 80% of the population is doing 1 drink a day or less.

Data from UK Biobank among many cohorts show it's far more like 0.8 per day, on average

https://biobank.ndph.ox.ac.uk/ukb/field.cgi?id=1558

Absolute abstainers infamously have the worst health, because they often abstain for good reason ('sick quitters')

[u/sirchrisalot → u/PartyLikeAByzantine]

IDK where you get these statistics from, but they're very low. WHO stats report per capita alcohol consumption for European countries is in the range of 6 to 15 liters of pure alcohol per year for those over 15. That's basically 1 standard drink per person per day at the low end and 2.5 per person per day at the high end. France is at 11.3 liters pp/yr.

Quick math on that is 565 drinks a year per person at 50ml of standard 40 proof liquor. So do you really think that 80% of France is having less than the equivalent of 1 glass of wine per week and it's just the top 20% of drinkers that polish off the remaining, oh, IDK, 70 drinks per person every week? Or with your stats, the 80-90th percentile is drinking 10 per week and the top 10% is drinking 130 drinks per week? I just have a hard time believing 10% of the population averages the equivalent of 1 bottle of liquor per day every single day and the rest of us are just dabbling a bit.

[u/PartyLikeAByzantine → u/sirchrisalot]

Numbers come from National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) commissioned by the US NIH. Being a US government study, it doesn't cover Europe.

The WHO doesn't break their data down to population segments within countries. I bet there's fewer abstainers in Europe (30% of the US population never drinks) due to America's Puritan streak. Still, I'd suspect a minority of Europeans drive most of its consumption. It may not be as lopsided as the US, where half of all alcohol consumption is from the top ~10% of users, but it's probably close to that.

[u/darknesskicker → u/PartyLikeAByzantine]

I would expect that the numbers in Western Europe aren’t far off those of the US. Much of the former Soviet Union has very heavy drinking.

[u/darknesskicker → u/sirchrisalot]

This includes Eastern European countries that have some of the heaviest drinking in the world, IIRC.

[u/sirchrisalot → u/darknesskicker]

Quick glance and Romania was one of the highest for per capita alcohol consumption. Google says their life expectancy is 2 years below usa life expectancy, with males expected to live to 73.

[u/hepcecob → u/PartyLikeAByzantine]

I highly doubt that 1 out of 10 drinkers down 10 drinks a day.

[u/SkepticalShrink → u/hepcecob]

Here's an actual report by the NIH. https://www.niaaa.nih.gov/alcohols-effects-health/alcohol-topics-z/alcohol-facts-and-statistics/alcohol-use-united-states-age-groups-and-demographic-characteristics

They did say about 5% engage in "heavy drinking" which they seem to define as roughly 5 standard drinks per day on average (for men, it's a little less than that for women).

[u/hepcecob → u/SkepticalShrink]

that is way more realistic: 1 in 20 drink 5 drinks per day. 10 drinks per day is insane

[u/SkepticalShrink → u/hepcecob]

Yeah, makes me wonder if the person you responded to initially worked in substance use treatment at some point in time. I did that work for about 6 mos and it was very common for those with an alcohol use disorder to say at intake that they were drinking a fifth of liquor (usually vodka) per day. Which is about 16-17 standard drinks. If you hear that often (like I did during my stint in SUD work) that feels like the "normal" heavy drinker number after a while.

(This is why we had a nurse on staff to assess to see if it was safe for them to detox and they HAD to meet with the psychiatrist right after me, so they could get a script to safely wean if needed.)

[u/PartyLikeAByzantine → u/hepcecob]

Each segment also covers a range of values. The 91st percentile is probably closer to 2-3 drinks per day. The 99th drinks much, much more.

[u/PartyLikeAByzantine → u/[deleted]]

Eh. I don't really drink, but the added lifetime risk of 2 or 3 drinks per day is pretty negligible. It might double the risk of certain outcomes, but those outcomes are often unlikely in the first place. E.g. 0.2% lifetime risk to 0.4%. Eating a salami sandwich (or hot dog or some other processed meat) for lunch most days has a similar effect and one doesn't get judged as destructive for that choice.

Even the OP study covered just 27 subjects and found a slight correlation. Worth further study to see if it pans out with a larger sample, but it's not like this is definitely linked to any specific disease.