14 July 2016

The Riddle of Medicine

Colon cancer, heart disease and dementia are receding, but no one can explain why

marks, GeektimesFor links to sources, see the original article – VM

They say that no one dies of old age. People are dying because of diseases. First of all, these are cancer and cardiovascular diseases. In the recent past, the number of patients with dementia, heart disease and bowel cancer has been constantly increasing. 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), mortality has decreased.

Scientists called it the "mystery of medicine." It's not even surprising that diseases are receding, but that progress in the medical field is not at all the main reason for such a 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 wealthy countries, cancer, cardiovascular diseases, and strokes have always been leaders in the number of deaths. Nothing has changed here, but people are now getting sick less often, and diseases occur at a later age. The result is that people live longer, and their health remains good for many years. Why? "It's not difficult 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."

Colon cancer seems to be slowly going away. The number of deaths of cancer patients of various 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 bowel cancer reached a maximum. Now this indicator 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, National Cancer Institute, USA)

One can think that the reason for the retreat of diseases is in the progress in medicine. For example, screening (from the English screening – mass examination) has become a very common method of early diagnosis of cancer. But this technology, like other medical achievements, is not the main factor in the recovery of civilization. According to scientists studying this issue, there should be other factors that affect the reduction of the number of diseases and the reduction of mortality among cancer patients. None of the studies on colon cancer screening show a link between the popularization of this technique and a 50% reduction in the mortality of patients with bowel cancer. This result is not shown by the work on the screening of other types of cancer.

The number of hip fractures has also decreased. The decrease is significant – several tens of percent over the past 30 years. And although medicine has given good medications to patients with osteoporosis, not many people take them so that the effect is so significant. Among American women over the age of 65, less than 10% take such drugs.

There is a slightly strange assumption that there are fewer hip fractures because there are more overweight people 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 of the California Pacific Medical Center Research Institute and the University of California, San Francisco. The real reason for the decrease in the number of hip fractures is still unknown.

Patients with dementia (acquired dementia) it's also getting smaller. 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 trend had to spend a lot of time in order to convince the medical community of their rightness. There are fewer patients with dementia both in the USA and in European countries. Since 1977, the number of such patients has decreased by 20% every decade.

A study by American scientists shows that the average number of cases of dementia among the elderly over the age of 60 in 1986-1991 reached 3.6 per 100 people. In 2004-2008, this number dropped to 2 cases per 100 people. As you know, in rich countries the population is rapidly "aging", that is, there are more and more elderly people. And the total number of people with dementia may show positive dynamics. 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 are one of the causes of dementia in humans. People suffering from cardiovascular diseases are also susceptible to Alzheimer's disease. This is where the control of blood pressure and cholesterol levels in the blood comes to the rescue. 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 doctors conducting information training for the elderly. The reasons for the trend remain unknown.

Another example of the negative dynamics of deaths is a heart attack. The situation is slightly different here – the number of deaths caused by myocardial infarction has been declining for about 50 years. The decline has slowed down somewhat, but the negative dynamics still persists. In the USA, a heart attack kills 300,000 a year. But the number of deaths decreased by 60% from the maximum figures. Perhaps the promotion of a healthy lifestyle, more advanced medications, and medical care have a positive impact. According to the 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 No. 1 in 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 food. Or maybe because antibiotics have affected the prevalence and viability of the H. pylori bacterium, which causes many forms of stomach cancer.

In the same 30s of the last century, 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 No. 1", but their impact on the number of deaths in patients is decreasing. Cancer may soon come out on top, although the number of cancer deaths per 100 people is also decreasing.

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

So far, we are talking only about the so-called "secured" countries. But the trend is obvious, and they cannot explain it yet. Perhaps, some scientists say, the reason is a change in the aging process, a change in some intracellular mechanisms of aging. All this is just guesswork, the real reason has yet to be found.

Portal "Eternal youth" http://vechnayamolodost.ru  14.07.2016

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