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Imagine living a century ago, when on average you could expect to live only to about 47 years in the U.S., or to about 30 years in India or China. Life expectancy today has increased in China to 75 years and in India to 66 years; you can now expect to live about 78 years if you are born in the U.S., and even longer if you live in Japan or Iceland. Astoundingly, about half the gains in health over all recorded history were achieved in just the past 60 years—and most occurred before the introduction of modern drugs, medical devices or treatments. They came from public health programs and disease prevention.
It doesn’t take great imagination to recognize that preventing diseases provides far greater value than trying to treat them after people are sick. Consider some of the great prevention successes to date, such as vaccines. Childhood infectious diseases used to kill or cripple millions of children. Yet thanks to vaccines, diphtheria, tetanus, whooping cough, measles, mumps and polio are almost unknown today. People can debate whether to take the H1N1 influenza vaccine now, but if the current strain of “swine flu” were as virulent as the 1918 H1N1 strain, without a vaccine, 50 million to 100 million people worldwide would lose their lives.
Deaths from heart disease in the U.S. have dropped by more than 60 percent, and strokes, by 70 percent, since 1950. A major part of that improvement came from the drop in cigarette smoking among U.S. adults from 42 percent in 1950 to now less than 20 percent. Part of the reduction in heart disease was achieved with better diet and exercise; the remainder can be credited to preventive treatment for people at risk with drugs, like antihypertensive agents, lipid-lowering medications and aspirin.
Primary prevention strategies will continue to focus on avoiding known risks, such as smoking, poor diet and lack of exercise, and exposure to toxic materials in the environment. An obvious future challenge will be to develop new preventive vaccines against the big infectious killers—HIV/AIDS, tuberculosis and malaria—and the viruses, bacteria and parasites that cause diarrhea and respiratory diseases, particularly in poor countries.
The success of vaccines and other preventive measures has enabled most of us to survive to older ages, which affords us the ironic luxury of developing chronic diseases: heart disease, diabetes, cancers, Parkinson’s, Alzheimer’s and more. Ongoing research will focus on developing drugs that can specifically prevent or delay such ailments, and enable us to function well even while afflicted with inevitable ones. The ultimate challenge will be to make the products of modern scientific knowledge—those vaccines and drugs for prevention and treatment—affordable and accessible to people of all countries.
Shifts in global demographics—including population, age and distribution of disease—are redefining health challenges and priorities.
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