In the latest issue of the Journal of Economic Perspectives, David Cutler, Angus Deaton, and Adriana Lleras-Muney write,

The argument for the role of public health in reduced mortality is made most prominently by Samuel Preston (1975, 1980, 1996). If economic growth were the sole reason for improved health, countries would move along the “Preston curve” shown in Figure 1, but the curve itself would remain fixed. However, even at a given level of income, people live substantially longer today than they did in the past. For example, China in 2000 has the income level of the United States in the 1880s, but the life expectancy of the United States in 1970, about 72 years. Preston estimates that only about 15 percent of the increase in life expectancy between the 1930s and 1960s is a result of increases in income alone.

The article is an excellent survey of the effect on mortality of economic growth, public health, medical care, and other factors. My instinct is that if we had frozen medical care at the knowledge level of, say, 1965, our average longevity would not be much different. The authors argue otherwise. They use facts and analysis, which beats instinct.