Monday, April 29, 2013
A simple question
In general, would you say your health is excellent, very good, good, fair or poor?
Believe it or not, how you answer that question is a good predictor of how long you will live -- whether you are a young person, or an older person with cancer. It doesn't much matter exactly how it's worded -- you can ask, "How would you rate your overall health during the past week?" or "How do you regard your health?" or anything similar. It doesn't really matter what response categories you offer either -- the excellent to poor scale I used, or a 100 point visual analogue scale, or a seven point scale. And it doesn't really matter if you ask people to compare themselves to others their own age, or just ask the question in a very general way.
The power of this question is a bit of a mystery. People are presumably using different comparators -- e.g. how they felt before they were diagnosed with Annamannapunna, or people they know, or their parents at the same age, or some imaginary ideal. Who knows?
And health obviously means different things to different people. It's actually impossible to define compellingly. "The absence of disease" seems basically circular, since the only way to define disease is as a state of less than optimal health. "Well being" might be a synonym but then what does that mean? People usually think of health as having biological, psychological and social components -- some people want to sneak in spiritual but I think that's just a psychological state. But which of those is most important? If you're happy even though you have MS are you healthy? What if you're the world decathlon champion but you're sad?
None of this seems to make any difference. The question is better correlated with the highly specific and reliable end point of longevity from time now than most physical indicators. Why do you think that is? And what does it mean to you?