The mystery of medicine: colon cancer, heart disease and dementia are receding, but no one can explain why

They say that no one dies of old age. People are dying by millions due to disease. First of all, it is cancer and cardiovascular diseases. In the recent past, the number of patients with dementia, heart disease and intestinal cancer has steadily increased. The number of deaths caused by these diseases also increased. Now scientists are surprised to note the opposite trend. In a number of countries, the number of patients with such diseases has decreased (according to such an indicator as the number of cases per 100 people), and mortality has decreased.

Scientists have called it the " mystery of medicine ." Surprisingly not even the fact that diseases recede. And the fact that progress in the medical field is not the main reason for this retreat. Do not think that diseases disappear, no. There are fewer sick people; the diseases listed above still kill millions of people a year. But the negative dynamics of the number of cases is also a fact .

In the United States and other affluent countries, cancer, cardiovascular diseases, and strokes have always been the leaders in the number of deaths. Nothing has changed here, but people now get sick less often, and diseases come later in life. The result - people live longer, and their health remains good for many years. Why? “It’s easy to come up with interesting, convincing explanations,” says Professor David S. Jones, a Harvard medical historian. "The more difficult task is to choose the right explanation from the whole range of theories."
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Colon cancer seems to be gradually disappearing. The number of deaths of cancer patients of different types has been decreasing since 1990 (data for the USA). If we consider only colon cancer, the number of deaths among patients with this type of cancer has fallen by 50% since 1980. Then the number of cancer patients with intestinal cancer reached a maximum. Now this figure is gradually decreasing, the negative dynamics of mortality due to this type of cancer is also decreasing.


The number of deaths per 100,000 people among patients with colon cancer aged 50 years and older (source: SEER Program, US National Cancer Institute)

It may be thought that the cause of the retreat of diseases is in progress in medicine. For example, screening (from the English. Screening - mass screening) has become a very common method of early detection of cancer. But this technology, like other medical advances, is not the main factor in the recovery of civilization. According to scientists studying this issue, there should be other factors that influence the decrease in the number of diseases and the decrease in mortality among cancer patients. None of the studies related to colon cancer screening show a connection between the popularization of this technique and the reduction of mortality in patients with bowel cancer by 50%. This result does not show the work on screening for other types of cancer.

The number of hip fractures has also decreased . The decline is significant - a few tens of percent over the past 30 years. And although medicine gave patients with osteoporosis good medicines, not many people take them for the effect to be so significant. Among American women over 65, these drugs take less than 10%.

There is a bit of a strange assumption that there are fewer hip fractures because more people are overweight in rich countries. And these people have stronger bones, because the skeleton constantly has to cope with increased loads. In fact, this assumption does not hold water, says Professor Stephen R. Cummings from the California Pacific Medical Center Research Institute and the University of California, San Francisco. The real reason for reducing the number of hip fractures is still unknown.

There are also fewer patients with dementia (acquired dementia). The first information about the negative dynamics of the number of such patients appeared more than 10 years ago. But the scientists who discovered this tendency had to spend a lot of time to convince the medical community that they were right. There are fewer patients with dementia in the United States and in Europe. Since 1977, the number of such patients has decreased by 20% every decade .



A study by American scientists shows that the average number of dementia cases among the elderly over the age of 60 in 1986-1991 was 3.6 per 100 people. In 2004–2008, this number dropped to 2 cases per 100 people. As is known, in rich countries, the population is rapidly “aging”, that is, the elderly are becoming more and more. And the total number of cases of dementia may show a positive trend. But if we take the ratio of the number of cases per 100 people, it is clear that the disease is also receding.

In this case, scientists have an explanation. The fact is that a number of cardiovascular diseases is one of the reasons for the onset of dementia in humans. People suffering from cardiovascular disease are susceptible and Alzheimer's disease. Here comes to the aid control of blood pressure and cholesterol levels in the blood. Also, doctors constantly talk about what helps to avoid the appearance of dementia and Alzheimer's disease. But such a sharp decrease in the number of patients with dementia cannot be caused only by the good work of physicians conducting information training for the elderly. The reasons for the trend remain unknown.



Another example of the negative dynamics of deaths - heart attack . Here is a slightly different situation - the number of deaths, the cause of which - myocardial infarction has been decreasing for about 50 years. The decline slowed down somewhat , but the negative dynamic still persists. In the US, a heart attack kills 300,000 per year. But the number of deaths has decreased by 60% from the maximum rates. It is possible that the promotion of a healthy lifestyle, more advanced medical preparations and medical care have a positive effect. According to researchers, all this is not enough for such a significant reduction in the number of deaths.

Stomach cancer in the 30s of the last century was number 1 on the list of cancers with the maximum number of deaths. Now this disease is the cause of only 1.8% of deaths from the total number of deaths of cancer patients with various types of cancer. And no one knows why stomach cancer has receded. Maybe because people started eating healthier foods. And maybe because antibiotics influenced the prevalence and viability of the H. pylori bacterium, which causes many forms of gastric cancer.



In the same 1930s, the number of deaths from tuberculosis decreased. But more and more people began to die due to cardiovascular diseases. By 1960, about a third of all deaths in America were due to this type of disease. But now cardiovascular diseases are receding. They can still be called "killer number 1", but their effect on the number of deaths in patients is reduced. Soon cancer may come out on top, although the number of deaths from cancer per 100 people is also decreasing.

Even the number of relapses of diseases, as well as the number of deaths of patients with chronic diseases is decreasing.

For the time being, this is only the so-called “wealthy” countries. But the trend is there, and can not explain it yet. Perhaps, some scientists say, the reason is a change in the aging process, a change in some kind of intracellular mechanisms of aging. All this is just a guess, the real reason is to be found.