95 



SUPPLEMENT 4 / 7 1 



Life expectancy (years) 



5,000 10,000 15,000 20,000 25,000 

 Income per capita 

 (1991 international dollars) 



FIGURE n. 11 Life expectancy and income 

 per capita for selected countries and periods. 



NOTE "Intemational dollars are derived from 

 national currencies not by use of exchange rates 

 but by assessment of purchasing power. The 

 effect is to raise the relative incomes of poorer 

 countries, often substantially." 

 SOURCE: Samuel H. Preston. Nathan Keyfitz. and 

 Robert Schoen, Causes of Death: Life Tables for 

 Sational Populations (New York: Seminar Press. 

 X')"!). as reprinted in The World Bank. The World 

 Development Report 1993 Infesting in Health 

 (New York: Oxford University Press, 1993). 



11.13 illustrate how the different parts of our system interact to produce changes 

 that ultimately lead to increases in the qualirv' of our lives. 



Consider, for example. Figure 11.12, which illustrates the steps leading to 

 reductions in mortality from high blood pressure.' From the 1930s to the 196()s, 

 research funded by private nonprofit groups, the Veterans Administration, and the 

 National Institutes of Health revealed dietary and behavioral risk factors associated 

 with high blood pressure. An early and important step was finding a way to mea- 

 sure blot)d pressure quickly and cheaply, and to correlate those measures with 

 diseases. Rigorous epidemiological studies confirmed suspected links between high 

 blood pressure, stroke (and later heart disease), and premature death. PaTrallel 

 clinical trials demonstrated that treatment for lowering blood pressure prevented 

 stroke, death from heart disease, and cardiac and renal failure. The National High 

 Blood Pressure Education Program, built on these findings, commenced in 1972. 

 Since then, changing social norms, individual exercise and diet decisions, and better 

 medical management have reduced the incidence of hypertension by more than a 

 third, and reduced stroke mortalin- by over 60 percent,- a remarkable achievement. 

 For millions of Americans, a broad base of research — spanning the full range from 

 social and behavioral research to molecular biotechnology— has meant the differ- 

 ence between life and death. 



As epidemiological and behavioral research progressed, a complex web of 

 biological factors also was uncovered through clinical investigations and basic 

 biological research. This line of research was funded predominantly by the federal 

 government, and supplemented by hospitals and private sources. Private pharma- 

 ceutical firms made investments comparable in magnitude to federal funding, but 

 focused on narrowing the search for specific agents and clinical testing to prove 

 their worth. Drugs lower blood pressure by reducing fluid retention (diuretics), by 

 influencing nerve impulses transmitted to the heart and blood vessels (beta-blocking 

 agents), and by reducing resistance to blood flow in small peripheral arteries (cal- 



