statistical difficulties

[miriam_e]

In a couple of places recently I've read the uncritical statement that caffeine and nicotine have some apparent protective effect against alzheimers. I find this difficult to believe. I have seen spurious statistical effects before and have to wonder if this is another. Did study control for the number of people killed by cigarettes and coffee? If people die earlier from cigarettes then a younger, intrinsically more resilient group will remain, who may well be less likely to get alzheimers, but not because nicotine protects; it would be simply that the cigarettes had already killed the most susceptible.

I know people are fond of saying that caffeine is safe, but I frankly don't believe it (to my shame I do drink caffeine). When I was a kid I embarked on an experiment with a friend at school to mutate fruit flies by feeding caffeine to them. Doesn't sound like a safe substance to me. Doesn't it strike anybody else as odd that caffeine producing plants are rendered fairly safe from pests. Why would that be do you suppose? Perhaps the insects are, in a sense, smarter than we are. I am almost willing to bet that some day in the future we will find that caffeine has been afflicting society with massive health problems that we have been studiously ignoring, just as we did for so long with cigarettes, and still do to some degree with alcohol.

Comments

[miriam-e.livejournal.com]

Ummm... you may be right. I may be getting a little mixed up and the report on nicotine may have concerned parkinsons. My points would still hold though. I'd have to see really carefully prepared figures to believe they'd disentangled all the complicating factors properly... and I actually don't think any analysis is really capable of doing that yet.

As to what alzheimers really is... that seems less and less sure. I used to favor the idea that aluminium toxicity was involved. It still bothers me to the extent that I don't use any aluminium cookware. And prion infection (mad cow) is almost certain to cause some of the cases. But for the bulk of cases, nowadays I tend to lean towards the idea of some kind of infection causing the body to attack itself, similar to how some autoimmune diseases may work. I don't think the immune system is allowed in the brain, but there are still protective methods the brain uses against infection, not least of which is apoptosis -- cell suicide.

However, in the end I really have to admit that I just don't know. I'm not really attached to this or any other explanation, and will be delighted when the puzzle is finally solved. I bet it ends up being something nobody was expecting, but really obvious when all the clues are laid bare. We'll all look at it and say, "How did nobody see this?" (Imagine the Romans and their lead-lined water storage.)

How we treat people with alzheimers and other long-term problems can be terrible. Our over-reliance on drug quick-fixes is awful. My own feeling is that it won't improve a lot till we have personal robots to help us. It is coming, but is still a little way off. Damn.

Decades ago I heard a talk by a guy who was a doctor at a nursing home who insisted that many cases of "dementia" were actually confusion resulting from low fluid intake. As we get older our regulatory mechanisms (temperature control, appetite, thirst) fade. He said that giving people water instead of diuretic drinks like tea and coffee at this home made a major improvement to their lives. (Knowing how addicted to their tea and coffee some people are I bet they were not happy about it.) I don't know how correct he was, but I have noticed my Dad tends not to drink much water unless Mum pushes him to. And dehydration does lead to confusion.