Priorities . . .

In my last post, I made a jest about spontaneous human combustion as a major public health problem, but a commenter wants me to get real. So here's my basic concept of the public health universe.

In every society, social and economic status is strongly associated with life expectancy, health status, and the prevalence of disability, even where there is universal and equal access to health care. In addition to these disparities within societies, it is now generally held that societies with more inequality tend to have worse population health than societies of comparable aggregate wealth but less inequality. Population health is also strongly affected by environmental conditions such as water and air quality; culturally and economically influenced behaviors such as tobacco and other substance abuse, diet, and physical activity patterns; and social conditions associated with psychological stress and violence.

The World Health Organization tends to view social determinants of health and resulting disparities in terms of inequities among countries, but it is also true that even after controlling for aggregate wealth, countries with less inequality have better health indicators than countries with more inequality. The United States is actually an outlier that contributes powerfully to this association -- in spite of our great wealth, we also have exceptional inequality. In fact, using one simple measure, the ratio of income between the top 10% and the bottom 10%, the U.S. is among the most unequal countries in the world -- we have greater inequality than Nepal, Ghana, Cameroon, Benin, and most of the poor countries. (Burkina Faso, anyone?) The same is true by other measures. (The Wikipedia table lets you sort by various indicators.)

And, we also have much lower life expectancy and higher infant mortality than would be predicted by our relative wealth. In fact our life expectancy at birth in 2007 was about the lowest among the wealthy countries, although obviously we're ahead of places like Ghana on that measure.

We don't completely understand the mechanisms that link social inequality to poor health. Obviously people in the poor countries are subject to severe malnutrition, contaminated water, and untreated infectious diseases which are unlikely to plague people in the U.S. (although it does happen). But even our poor people generally have clean water and enough to eat, and can get antibiotics if critically needed. Tobacco, obesity, occupational hazards, exposure to air pollution, and other measurable risks (including fire, BTW) are associated with socioeconomic status. We can figure out why these associations exist and work to ameliorate them, but of course it would be even better if everyone was better educated and more financially secure. That would be getting at root causes. And, even after we control for everything we can think of, there is still a residual, and substantial, socioeconomic gradient in health status that we can't really explain.

Basically, it hurts to be at the bottom. More justice means better health. So ultimately, that's my priority.