In “A Hierarchy of Diseases“, I discussed various classes of diseases and some of the challenges that each class poses as we attempt to develop cures. In this article, we will look at some data to see where we are in addressing some of these challenges.

In the 1950s, heart disease was a major killer of Americans. But, we have learned how to address much of the heart disease we face. Primarily, we can alter our diet to manage heart disease (e.g. smaller portions, limit unhealthy fats, reduce sodium intake, drink one serving of alcohol each evening) [1,2]. Older people who are at risk of having a heart attack can take a low dose of aspirin to reduce their risk [3]. Aspirin prevents blood clots; blood clots in the vasculature of the heart can reduce perfusion and cause a heart attack. Finally, heart surgeries have become much safer. Minimally invasive heart surgeries reduce the length of the hospitalization stay, reduce complications due to surgery, and reduce the pain associated with the surgery [4].

As we have become more effective at addressing heart disease, the incidence of cancer has risen (see the figure below). Between 1950-2014, the ratio of cancer/heart disease has increased from approximately 40% to approximately 100% [5].

Unfortunately, the trend is not uniform across the United States. As the following figure shows, much of the south and the mid-west is still dying more from heart disease than from cancer [5].

If we look at the following figures, we see that the trend in heart disease is spatially correlated with the obesity and physical inactivity of the regions (data is shown for the period between 2014 to 2016) [6]. Not surprisingly, poor eating habits and a lack of exercise lead to heart disease. (I once heard the cardiologist Dr. Michael McConnell speak at Stanford University. He said that 98% of the time he spends speaking to patients is used informing them that if they eat right and exercise then their health problems would go away. This seems like a huge waste of expertise.)

Very luckily, stroke is correlated with heart disease. The better we are at addressing heart disease (either through preventative measures or through medical interventions), the less stroke our nation experiences. This is because cleaner blood vessels (with less cholesterol and calcium buildup) have less of a chance of having blockages break off and cause disruptions to perfusion in the brain. You can see the occurrence of death from stroke in the figures below. The left image shows deaths during the period from 2005 to 2007, and the right figure shows deaths from 2014 to 2016 [6].

Even though the spatial trends are the same for both time periods (and the same as heart disease), the scales are very different. Between 2005 to 2007, 88.2 people in every 100,000 died of stroke [7]. However, between 2014 to 2016, 72.2 people in every 100,000 died of stroke [7]. This represents a per capita decrease of nearly 20%! The size of the problem is still extremely significant; every year nearly 800,000 people have strokes (with approximately 200,000 of those being a recurrent stroke), and approximately 150,000 people will die each year from stroke.

So where are we at? We have largely addressed heart disease, and our incidence of stroke is decreasing. As a consequence the death rate of cancer is increasing (as shown above). Because we are able to address some cancers, the incidence of rare and untreatable cancers is increasing. Approximately 200,000 cases of rare cancers were expected in 2017 [9]. And, the incidence of death due to Alzheimer’s is increasing. The figure below shows how death rates for various diseases have changed over time [10].

We are living longer, and we are dying of different things. Sadly, the reduction in quality of life associated with each death differs significantly. Whereas a heart attack can be a relatively painless death (within seconds), cancer will probably not. People can live many years with the dementia resulting from stroke or Alzheimer’s disease. And so we’ve traded a longer life for a different kind of death. This will change in the future. Cancer was initially treated with radical surgery sans anesthesia [11]. (Famously, John Adams’ daughter had a mastectomy without anesthesia to remove a breast lump [12]). As treatments have improved, people can now live a full life for a long time with cancer. And we needed the original cancer patients to figure out how to do this; we needed to test treatments to see what worked. We’re in a similar situation now with the diseases of dementia: learning and testing.

A final note: Congress is considering the KITTEN act; a bill to reduce experimentation on cats [13]. Recent research shows that cats are a natural model to study Alzheimer’s disease [14]. There are already extensive regulations to prevent the unnecessary and useless experimentation on animals. If this act passes (submitted both to the House of Representatives [15] and to the Senate [16]), congress will specifically hinder research on Alzheimer’s disease. In the senate, it has been sponsored by senators Merkley, Booker, Peters, and Udall. In congress, this act has been co-sponsored by Katherine Hill, my home town congresswoman.

[1] https://www.mayoclinic.org/diseases-conditions/heart-disease/in-depth/heart-healthy-diet/art-20047702

[2] https://www.mayoclinic.org/diseases-conditions/heart-disease/in-depth/red-wine/art-20048281

[3] https://www.health.harvard.edu/heart-health/rethinking-low-dose-aspirin

[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3134935/

[5] https://www.cdc.gov/Pcd/issues/2016/16_0211.htm

[6] https://nccd.cdc.gov/DHDSPAtlas

[7] https://nccd.cdc.gov/DHDSPAtlas/Reports.aspx

[8] https://www.cdc.gov/stroke/facts.htm

[9] https://www.cancer.org/latest-news/cancer-facts-and-figures-death-rate-down-25-since-1991.html

[10] https://www.cdc.gov/nchs/products/databriefs/db116.htm

[11] Mukherjee, The Emperor of All Maladies: A Biography of Cancer

[12] McCullough, John Adams

[13] https://www.congress.gov/bill/116th-congress/senate-bill/708/cosponsors?q=%7B%22search%22%3A%5B%22interdict+act%22%5D%7D&overview=closed

[14] https://www.ncbi.nlm.nih.gov/pubmed/26651821

[15] https://www.congress.gov/bill/116th-congress/house-bill/1622/cosponsors?overview=closed#tabs

[16] https://www.billtrack50.com/BillDetail/1099254