Infants born in America in the early 20th century could not expect to live very long. In 1900, the life expectancy at birth in the U.S. was 46.3 years for males, and 48.3 years for females1. The leading causes of death in 1900 were acute diseases like pneumonia and influenza; tuberculosis; and diarrhea, enteritis, and ulceration of the intestines2. Children were particularly susceptible to these diseases, which were not easily treated in the early 1900’s. Consequentially, many people did not survive into late adulthood.
By the 21st century, disease control, modern medicine, vaccinations, and advanced diagnostic tools greatly increased the probability of longevity in the United States. By 2014, life expectancy at birth had increased to 76.4 years for males, and 81.2 years for females3. Humans are pushing closer to the biological limits of life expectancy4, which makes one wonder, is it possible to die just because our bodies are too old to continue functioning? Is it true that one can simply die from natural causes?
We sometimes use the phrase “death from natural causes” synonymously with “death from old age.” But death from natural causes has its own legal meaning. According to the Physicians’ Handbook on Medical Certification of Death from the Center for Disease Control and Prevention, “natural” deaths are any that did not result from an accident, suicide, or homicide5. Of the 2,626,418 deaths in the U.S. in 2014, 52% died from heart disease, cancer, or chronic lower respiratory diseases3, which are considered natural causes.
Before the deceased can be buried or cremated, the state must issue a death certificate. The death certificate contains both demographic data (age, occupation, race, marital status etc.) as well as the cause of death as determined by a medical examiner. Because death certificates contain significant information for public health and medical research, the medical examiner must be as specific as possible when determining a cause of death. For instance, “old age” is not a cause of death because there is always a more direct cause6.
However, many elderly patients in the U.S. suffer from multiple, often age-related conditions that may have contributed to their death. On the death certificate, the medical examiner will indicate the diseases or conditions that led to the patient’s death in order of their contribution. The condition that ultimately caused the patient’s death is called the immediate cause. Other contributing conditions that indirectly resulted in the patient’s death are called underlying causes. For example, consider (a very hypothetical) Bob. Bob was 67 years old, and had diabetes for 15 years. For many years, his diabetes was under control. For the past two years or so, Bob hadn’t been managing his condition well. For instance, he wasn’t checking his blood sugar regularly and had stopped taking his medication. About two months ago, Bob’s blood sugar became too high. His body tried to excrete the excess sugar by passing it through his urine. This caused Bob to produce a lot of urine, which required him to urinate frequently. After some time, Bob began to feel unwell. He urinated very infrequently, and his urine became very dark. Although he didn’t feel thirsty, his body had entered a state of severe dehydration. The dehydration became so severe that Bob slipped into a coma a couple hours later. Five days later, Bob was still in a coma when his kidneys begin to fail. Eventually, his kidneys shut down completely, and Bob was declared deceased.
Here is an example of the Cause of Death portion of an example death certificate (again, Bob doesn’t exist, but his condition does)7. The medical examiner indicated Bob’s immediate cause of death as acute renal failure (kidney failure). He listed hyperosmolar nonketotic coma (the diabetes-induced coma) and diabetes mellitus (diabetes) as the underlying causes of death. He indicates approximately how long Bob had had these conditions before he died. Most death certificates will also inquire whether the deceased used tobacco or was recently pregnant to help elucidate deaths due to these causes. Finally, the medical examiner indicates the manner of death as natural. In other words, Bob may have died from kidney failure, but, like over 90% of the recently deceased, he ultimately died of natural causes8.
This is because natural causes are a manner of death, not a cause of death. A manner of death considers both the cause of death and the circumstances that caused it. Both Bob and someone recently deceased, but thirty years younger and with his exact condition would have both died from natural causes. On the other hand, two people with the same causes of death could have different manners of death. For instance, two people who died from organ failure due to prescription medication overdoses might have different manners of death depending on whether the overdose was accidental or intentional.
In some cases, the cause of death cannot be determined within the statutory time limit for filing the death certificate (typically 72 hours from the medical examiner taking charge of the case). The medical examiner will indicate one of two manners of death: “pending investigation” means that the manner of death could likely be assigned with more time or equipment. The cause of death can be revised at a later date. If the medical examiner determines it is impossible to declare the manner of death, he will indicate: “could not be determined.” This manner of death is ambiguous, makes legal action difficult, and is difficult to reverse. Consequentially, a medical examiner will exhaust all efforts to determine a manner of death before declaring that it could not be determined5.
It is possible that Grandma died natural causes this year, but that is the same as saying that Shawn died in a car accident or Leslie was killed by a motorist while bicycling on the road. These broad manners of death indicate under what circumstances these people died. The causes of death are much more specific: Grandma died from viral pneumonia she acquired from having the flu. Shawn died from blunt force trauma after his head hit the steering wheel during a high-speed collision. Leslie died from internal bleeding after being struck by a motorist who didn’t see her while making a left turn onto the road they were supposed to share. So yes, people can—and do—die from natural causes. However in the U.S., there is usually a more specific, medically explicable cause of death, which can ultimately help inform public health surveillance, medical funding, and legal policy.
- Table 22. Life expectancy at birth, at 65 years of age, by race and sex: United States, selected years 1900-2007. Link
- Leading Causes of Death, 1900-1998. Link
- NCHS Data Brief. Mortality in the United States, 2014. Link
- Dong et.al, “Evidence for a limit to a human lifespan”, Nature 538, 257–259, (2016).
- “Physicians’ Handbook on Medical Certification of Death”. Link
- Instructions included in the U.S. Standard Certificate of Death. Link
- “Instructions for Completing the Cause-of-Death Section of the Death Certificate”. Link
- Figure extrapolated from the causes of death listed in the Reference 3, assuming those who died from diseases did not acquire their disease through an earlier accident.