Given all that is happening in the world of vaccines and other public health, I thought I would go a little off topic. I usually think of public health as a near cousin to patient safety. Both work to prevent harms to people. Sometimes I feel that both are underappreciated and things that we take for granted. A patient entering a hospital may assume that the system is safe. After all, isn’t safety sort of a gimme? Same thing for the prevention of childhood diseases, aren’t they all pretty much taken care of?
Neither is true. Hospitals are not always safe, and the diseases that have afflicted children (and sometimes through them to us) still lurk out there waiting for us to stop believing in them.
When we think about some of the amazing medical miracles that we now hear about, it is understandable that people might believe that the greatest contributor to human longevity in the United States is due to modern medicine. Certainly things like antibiotics, cancer treatments, cardiac care, minimally invasive surgeries must be the reason that our lives are longer. So let’s take a closer look.
Historical Trends in U.S. Life Expectancy
- 1900: Average life expectancy was ~47 years.
- Today (2020s): Around 76–79 years.
- That’s a gain of ~30 years in a little over a century.
Contribution of Public Health
The majority of the above gain occurred before the modern era of advanced medical therapies (antibiotics, chemotherapy, ICU care). The things that contributed to this remarkable improvement are:
- Clean water & sanitation: Filtration and chlorination of municipal water supplies nearly eliminated waterborne diseases (typhoid, cholera).
- Vaccination: Eradication of smallpox, near-elimination of polio, and dramatic reductions in measles, diphtheria, and pertussis.
- Improved food safety & nutrition: Pasteurization, refrigeration, and regulation reduced foodborne illness and malnutrition.
- Tobacco control & injury prevention: Smoking cessation campaigns, seatbelts, airbags, and safer workplaces.
- Maternal & child health measures: Prenatal care, safe childbirth practices, SIDS reduction campaigns.
The CDC has consistently emphasized that about 25 of the 30 years of life expectancy gained since 1900 are attributable to public health advances, not medical care.
Contribution of Modern Medicine
This is not to diminish the gains made with the many advances in medical care. Yet, modern medicine has had a smaller (though still meaningful) impact, especially since the mid-20th century. These advances are things like:
- Antibiotics (post-1940s): Life-saving in pneumonia, tuberculosis, sepsis.
- Cardiovascular care (post-1960s): Statins, antihypertensives, coronary interventions reduced mortality from heart disease.
- Cancer care (post-1970s): Chemotherapy, radiation, targeted therapies improved survival in certain cancers.
- Critical care and surgical advances: Organ transplants, trauma care, neonatal ICUs.
These advances have mostly extended life at older ages and improved quality of life, rather than driving the initial massive increases in population-wide life expectancy that are achieved by keeping children and younger people healthy.
Bottom Line
- Public health measures account for the majority (~80–90%) of the increase in human life expectancy in the U.S. over the past century.
- Modern medicine contributes mainly to gains in survival at older ages and in high-risk populations, but only explains ~10–20% of the overall increase.
Go get your vaccines, wear your seat belt, don’t smoke, drink clean water, inspect food for safety, and make sure women have access to prenatal care. And support public health!