Wednesday, May 24, 2006

An Ounce of Prevention...

Prevention is a good thing, right? The health care system should spend more on prevention. That way we'd save money, prolong lives and avoid pain and suffering. Yes, probably. But sometimes it pays to look at concepts from a different angle, to abstain from the instant emotional reaction and to ask some hard questions, and I feel like doing that with prevention.

Take flossing. Suppose that you floss five minutes a day. That means spending more than a month flossing in the next forty years. Is flossing the best way to spend that month? What if you took the same time and meditated or performed jumping jacks? What are the health benefits of flossing like this?

The point of this example is not that you should stop flossing and grow green moss over your teeth. The point is that prevention also has its costs and sometimes these costs are considerable in time and perhaps also loss of enjoyment. We are told that exercizing is good for health, and it probably is. But is it still good if the person doing the exercizing hates every single minute of it?

There is something puritanical in the American fascination with prevention. If it hurts it must be good for you, so you should eat lots of bran while running around the kitchen and flossing. Then you will live for ever, and if you do not, well, it's your own sinful lifestyle that caused you to die. Sadly, nobody has yet managed to get out of this life alive, and in that sense all prevention is in vain. But we like to pretend that if we only cut out all the fat and the caffeine and the chocolates (!) it just might be possible to live forever. And those who fail to do so must have been bad. Perhaps they had too many hamburgers or eclairs. In any case, they deserved to die.

That puritanical whiff is something I intensely dislike, partly because I'm totally addicted to chocolate, but mostly because it's unbecoming. But prevention has other problems, and one of them is that its costs are rarely addressed. The assumption is that prevention saves money for the health care sector, and it may* do so, or at least some types of prevention do so, but the people doing the prevention will incur costs, both in money (buy dental floss and a skipping rope), time (exercize four hours a week) and psychological adjustments (learn to love cabbage).

And then there is the much bigger problem of establishing when prevention actually works. It's such a nice idea, prevention, that we'd love to just assume that it will always work. But it may not, and only proper medical studies can find out whether certain preventive measures are efficient.

Doing such studies can be difficult. Think about trying to establish whether being physically active reduces depression. If you are depressed you won't feel like being physically active, so finding a correlation between the two doesn't necessarily mean that physical activity causes less moodiness. To establish that one must study people who are not yet depressed, and these people must be randomly divided into two groups, one a control group who is allowed to live as they usually do, and the other a group which is assigned a physical exercize program. Then one must follow the two groups for quite a long time to find out if the depression rates differ. All this is also quite expensive.

Or consider what is sometimes called secondary prevention: the use of screening tests such as mammography to detect illnesses early. The rationale of such screening is that early diagnosis improves the effectiveness of treatment. But does it? Note that it's not enough to find that people who have been diagnosed early appear to live longer with the disease, as this is one obvious consequence of finding out about the illness earlier. Now, mammography has been shown to improve treatment outcomes in breast cancer, but whenever a new screening tool becomes available we should not just assume that it's an improvement.

In any case, prevention is like playing a game of chance. What you try to do is raise the odds that you will live long and happy. But this may not work out. You might run a marathon every day, eat nothing but cabbage and such, and get hit by an SUV during the twentieth mile of your daily run.

Which means that perhaps we should take prevention with a pinch of salt or some laughter. Or some nice dark chocolate.
*May because people who live a very long time often end up in nursing homes and these are expensive to run.