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Comment by Plough_Jogger | Hacker News Reader

"Consumption of >6 cups/day was associated with 53% higher odds of dementia compared to consumption of 1–2 cups/day"

Sleep hygiene is important, and it's critically important not to drink coffee late in... well, in the second half of the day really.

A lack of sleep is also a serious risk factor for dementia.

How much of this is just chronic sleep deprivation, I wonder?

There is also the possibility that the causation happens in reverse: those with early symptoms of dementia could be self-medicating with excess caffeine.

Or the coffee could be preventing other health problems so that more drinkers make it to dementia.

I doubt the study would fail to control for this; it's literally the most basic thing you can control for.

I drink coffee after dinner and sleep like a baby (an expression invented by those who have not had babies, but you know what I mean). But it was not always thus. The secret is drug tolerance!

That's about 1000mg of caffeine a day. A gram a day is diminishing returns for the average coffee drinker, and may signal addiction. Addiction is dangerous in itself, so we might explain the outrageous results of this study in that way. A lifetime on the edge is a recipe for disaster!

Depending on how and what you brew, a cup of coffee can contain 35, 100 or 150 mg of caffeine. People also invariably consider a mug of coffee the same as a cup of coffee.

A common reference in $my_country is that a cup (15 cl) of coffee usually contains circa 70 mg of caffeine.

It's really sketchy how their conclusions don't show the rate for 0 cups/day or 2-6 cups per day.

Figure 2 in the study says

  Adjusted for all covariates
  Odds
  1.09  None
  1.19  Decaf
  1.02  <1 cup/day
  1.00  1-2 cups/day
  1.02  3-4 cups/day
  1.13  5-6 cups/day
  1.53  >6 cups/day

Earlier they say

> We used light coffee drinkers (1–2 cups/day), instead of nondrinkers, as the reference group to avoid bias from individuals with poor health, who may avoid coffee due to their health status (49, 50).

Ahh, I could only see the truncated version on the site.

Though that's the reason they claim to have picked that group, as they were using biobank data they likely already knew the rates before the study started. Picking the lowest cohort from the get go is almost more sketchy.

Given the decaf numbers, it looks like caffeine is having a protective effect on the negative effects from the rest of the coffee!

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