In a typical year, the number one and two causes of death in the U.S. are Heart Disease, at about 650K deaths and Cancer at about 600K deaths. In 2020, Covid-19 became the third leading cause of death. But what happened in that same year to the other causes of death? Did heart disease and cancer remain at the same levels? Were suicides higher? This article answers those questions, and speculates about the reasons.
In the United States, in 2020, Covid-19 was the third leading cause of death at about 345,000 deaths . Note that Worldometers puts the number at 354,215 Covid-19 deaths in the U.S. Then the CDC’s National Vital Statistics System (NVSS) uses a higher number at 377,883 deaths, counting all deaths having Covid as the “underlying cause of death or a contributing cause of death” .
Heart disease and cancer, in 2020, remained the number one and two causes of death. But deaths from heart disease were significantly higher by about 31,000 more deaths, an increase of 4.7% . What could cause such an increase? Perhaps the stress of life during the pandemic increased the number of heart attack deaths. We also know that Covid-19 causes harm to the vital organs, including the heart in some cases. Some deaths from heart disease might have had Covid-19 as the underlying cause. (The NVSS data is supposed to include that type of death under Covid-19 as the cause of death, but they can only work with the data as they receive it.)
Some commentators speculated that 2020 would see many more deaths from suicide. But that appears not to be the case. Suicides in 2019 for the U.S. caused 47,511 deaths . The number for 2020 was 2,677 lower at 44,834, a drop of 5.6% . Perhaps keeping everyone indoors to a greater extent had some benefits on mental health, like spending more time with family…well, maybe not. In any case, the reduction is welcome.
Here is the rundown on the higher and lower numbers for causes of death in 2020, as compared to 2019. An increase of 31K for heart disease means that there were about 31,000 more deaths from heart disease in 2020, versus 2019:
Heart Disease (+31K)
Kidney Disease (+0.5K)
Respiratory Disease (-4K)
Accidents were up by about 20,000 more deaths, despite many persons traveling less and staying home more. It would seem that the higher percentage of persons working from home via computer and Zoom did not reduce accidental deaths. However, a large percentage of accidental deaths occur in the home. And with many children not in school, or in school via the internet, perhaps this explains the higher death rate for accidents.
Diabetes, Alzheimer’s, and Stroke were all up significantly in 2020. It may be that a past case of Covid-19, from which one recovers, makes existing co-morbidities worse, increasing risk of death from those causes. Covid-19 can affect the brain, the nervous system more generally, and the vascular system. These negative effects, even after the person recovers from Covid-19, could precipitate a later death from heart disease, diabetes, Alzheimer’s, or stroke, especially in someone with any of those comorbidities.
Influenza and pneumonia were up as causes of death in 2020, which is contrary to expectations. It would seem that if so many persons are wearing masks, social distancing, and being treated for a different respiratory infection, then flu and pneumonia would be lessened by competition, so to speak. But that was not the case. Deaths from flu/pneumonia rose, rather than falling.
Kidney disease only rose by about 500 deaths for 2020. This small rise is unexpected, given that other comorbidities seemed to result in a much higher increase. Perhaps the kidneys are less affected by Covid-19; or maybe those persons with kidney disease were at such a higher risk of death from Covid-19, that a later death from kidney disease was precluded.
Cancer deaths were down slightly, but about a thousand deaths. This fall is particularly interesting given the high increase in death from heart disease. Perhaps some of those persons who would have died from cancer, died from Covid-19 beforehand. This type of death due to timing would not be expected to have a large effect, so a thousand fewer deaths fits the hypothesis.
Deaths from chronic lower respiratory disease, other than Covid-19, were down by about 4,000 deaths. It is questionable whether this can be attributed to masks and social distancing, as flu and pneumonia deaths rose. It may simply be a case of competitive inhibition, whereby, if you have Covid-19, you will not also contract a different fatal respiratory disease. Then many of the persons susceptible to respiratory disease might also be more susceptible to Covid-19. So they died from Covid-19 instead of the other type of respiratory ailments.
The overall number of persons who died in 2020 in the U.S. was 3,358,814, which is down from 2,854,838 deaths in 2019. The difference is 503,976 excess deaths from all causes in 2020 versus 2019. Half a million more persons died in 2020 than in the previous year. Deaths in previous years had been declining, on the basis of deaths per 100,000 of the population:
731.9 in 2017 deaths per 100,000
723.6 in 2018
715.2 in 2019
828.7 in 2020 
But the increase of 503,976 includes only 377,883 deaths from Covid-19, which is 75% of the excess deaths for 2020. There are still another 126,093 non-Covid excess deaths, 25% of excess. And when we examine the top 10 causes of death, as explained earlier in this article, those deaths only explain about another 87,000 deaths. This leaves about 39,000 excess deaths in 2020 not explained by the top ten causes of death. And since suicide, the #11 cause of death in 2020, declined that year, no explanation is found there.
There are not many possibilities to explain those 39K excess deaths. Perhaps they were Covid-19 cases that were not reported to the States as Covid-19. That seems unlikely as the pandemic was so widely known that Covid-19 would be on the minds of anyone attempting to explain a death. It may be that the stress of a pandemic increases the risk of death from a wide range of other causes of death, below the top 11 causes.
But there is one more hypothesis. It has been noted in some studies that some Covid-19 patients recover, and then, several weeks later, die of unexplained causes. This seems to be due to the after effects of the stress on the body of suffering through a major disease.
“Excess deaths not attributed to COVID-19 could reflect either immediate or delayed mortality from undocumented COVID-19 infection, or non-COVID-19 deaths secondary to the pandemic, such as from delayed care or behavioral health crises.” 
1. Provisional Mortality Data, United States, 2020, April 9, 2021 / 70(14);519-522.
4. U.S. Saw Fewer Suicide Deaths in 2020 but More Drug Overdose Deaths, Reason.com, Elizabeth Nolan Brown, April 5th, 2021.
5. Woolf, Steven H., et al. “Excess Deaths From COVID-19 and Other Causes in the US, March 1, 2020, to January 2, 2021.” JAMA (2021). Study Link
Ronald L. Conte Jr.
“an author, not a doctor”