Skepticism about science and medicine

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Posts Tagged ‘correlation never proves causation’

Trust medical science at your peril: Correlations never prove causation

Posted by Henry Bauer on 2016/06/28

It was a long-known empirical fact that poverty, vagrancy, criminality, and apparently deficient intelligence all correlated with heredity to a considerable extent; they all ran in families and clans. The scientific confirmation that characteristics of animals are passed on from generation to generation, and the Darwin-Wallace explanation of evolution by natural selection of the fittest, made it possible to understand those aspects of human society. It was an obvious, scientifically sound conclusion that human societies could be steadily improved by restricting reproduction of the less fit and expanding the fertility of the fittest. Hence the eugenics movement, promoted by the most progressive, liberal people who were also the best educated, with an apparently justified faith in the reliability of what was at the time the most up-to-date the scientific knowledge (Trust science at your peril: Beware of scientism and political correctness). Those circumstances led to forced sterilization of tens of thousands in America and reinforced Nazis in their doctrines and practices of mass killing of the unfit — Jews, gypsies, homosexuals (Edwin Black, War Against the Weak, 2003).

Only in hindsight did the flaws and errors of the earlier scientific consensus become clear. We now appreciate that environmental and developmental influences can modify heritable traits quite dramatically. “Ill-bred” can be the result of social, economic, environmental factors as much, perhaps even more than any pre-ordained verdict of genetics; and “well-bred” individuals can spring from what might seem the least promising hereditary stock. In other words, the observed correlation between undesired social characteristics and clans was misinterpreted through neglecting the variable of environmental effects.

One lesson to be drawn is that bad science, wrong science, what some even call pseudo-science, can remain the accepted scientific consensus for decades, even in quite modern times, say, the middle of the 20th century. It is unlikely that a mere half-a-century later our societies have become immune from assuming that a mainstream scientific consensus must be true to Nature. Nothing guards our times from treating unjustified, misguided scientific claims as good science.

Unwarranted claims coming from scientists continue to be accepted if they appear minimally plausible and if they are consistent with world-views and vested interests of financial, social, or political powers.

The most sweeping lesson that remains to be learned is that correlations must never be taken as demonstrating a cause-and-effect relationship: there might always be in play an unsuspected variable. One of the earliest axioms taught in Statistics 101 is that correlations never prove causation. The evident correlation between biological kinship and undesirable behavioral traits was not a cause-and-effect relationship.

Many or most people have never learned that basic truth that correlations are not causes. Many others “know” it as a generalization but fail to apply it in specific instances, when an evident correlation could plausibly reflect cause and consequence — just as a genetic basis for undesirable characteristics seemed quite plausible to educated and expert people not so long ago.

Indeed, a large swath of modern medical practices is based on mistaking mere correlations for evidence of causation (“Correlations: Plausible or implausible, NONE prove causation”). For example:

HPV and cervical cancer

The National Cancer Institute offers a great deal of information about this:

Human papillomaviruses (HPVs) are a group of more than 200 related viruses. . . Sexually transmitted HPV types fall into two categories:
— Low-risk HPVs, which do not cause cancer but can cause skin warts (technically known as condylomata acuminata) on or around the genitals, anus, mouth, or throat. For example, HPV types 6 and 11 cause 90 percent of all genital warts. HPV types 6 and 11 also cause recurrent respiratory papillomatosis, a less common disease in which benign tumors grow in the air passages leading from the nose and mouth into the lungs.
— High-risk HPVs, which can cause cancer. About a dozen high-risk HPV types have been identified. Two of these, HPV types 16 and 18, are responsible for most HPV-caused cancers. . . .
>> Cervical cancer: Virtually all cases of cervical cancer are caused by HPV, and just two HPV types, 16 and 18, are responsible for about 70 percent of all cases . . . .
>> Anal cancer: About 95 percent of anal cancers are caused by HPV. Most of these are caused by HPV type 16.
>> Oropharyngeal cancers (cancers of the middle part of the throat, including the soft palate, the base of the tongue, and the tonsils): About 70 percent of oropharyngeal cancers are caused by HPV. In the United States, more than half of cancers diagnosed in the oropharynx are linked to HPV type 16 (9).
>> Rarer cancers: HPV causes about 65 percent of vaginal cancers, 50 percent of vulvar cancers, and 35 percent of penile cancers (. . . .) Most of these are caused by HPV type 16.

The Centers for Disease Control & Prevention offer advice on avoiding HPV cancers:

— Bivalent, quadrivalent and 9-valent HPV vaccines each target HPV 16 and 18, types that cause about 66% of cervical cancers and the majority of other HPV-associated cancers in both women and men in the United States. 9-valent HPV vaccine also targets five additional cancer causing types (HPV 31, 33, 45, 52, 58) which account for about 15% of cervical cancers. Quadrivalent and 9-valent HPV vaccines also protect against HPV 6 and 11, types that cause anogenital warts.
— Quadrivalent and 9-valent HPV vaccines are licensed for use in females and males; bivalent HPV vaccine is licensed for use in females.
What percent of HPV-associated cancers in females and males are caused by the 5 additional types in the 9-valent HPV vaccine?
— About 14% of HPV-associated cancers in females (approximately 2800 cases annually) and 4% of HPV-associated cancers in males (approximately 550 cases annually) are caused by the 5 additional types in the 9-valent HPV vaccine.

What evidence is there for these extremely specific claims of causation?

None, actually. The cited facts are merely that the stated strains of HPV have been detected in those proportions of those cancers. Those correlations don’t begin to indicate causation.

It may be worth recalling that the Centers for Disease Control & Prevention in the early 1990s had officially stated, on the basis of the same sort of data (epidemiology, i.e. correlations), that cervical cancer was an AIDS disease, caused by HIV.

One may sympathize with medical researchers for the impossibility of conducting experiments that would be capable of proving cause-and-effect; ethical, legal, and moral restraints make it unfeasible to use human beings as experimental guinea pigs. There would also be practical barriers: To determine whether a given treatment, in this case a vaccine, actually prevents cancer, a clinical trial would be necessary that spanned over decades and enrolled large numbers of human guinea-pigs, some of whom (controls) would not get potentially-cancer-preventing vaccine.

However, the inability to obtain proof does not justify proclaiming as fact, as these official agencies do, causative relations that are no more than speculation based on statistical correlations.

[The vaccines] “Gardasil and Cervarix have not been shown to be of any significant health benefit. They have been demonstrated to cause serious injuries. It’s scandalous that they were ever approved, and it’s scandalous that they remain on the market.

And they are far from alone on those scores among new prescription medications introduced in the last couple of decades” (Deadly vaccines, 2013/04/17 http://wp.me/p2VG42-24).

Alzheimer’s Disease

Sleep disorders may raise risk of Alzheimer’s, new research shows
Sleep disturbances such as apnea may increase the risk of Alzheimer’s disease, while moderate exercise in middle age and mentally stimulating games, such as crossword puzzles, may prevent the onset of the dementia-causing disease, according to new research to be presented Monday

A daily high dose of Vitamin E may slow early Alzheimer’s disease

Again, these are correlations speculated to be possible causes.

Semantics no doubt plays a role. One could report that sleep disorders, and lack of vitamin E, seem to be associated with a risk of Alzheimer’s. Medical jargon puts it like this: “sleep disorders, and lack of vitamin E, are risk factors for Alzheimer’s”. Then the media and public conclude that “risk factor” means something that tends to cause the associated effect.

See also “60 MINUTES on aging — correlations or causes?

Biomarkers

It is not feasible to test treatments for chronic conditions by actual outcome, because one would have to wait a couple of decades to determine whether regimen A or drug B reduces morbidity and mortality apparently associated with high blood pressure, or high cholesterol, or high blood sugar, or low bone density, etc. All those are statistically correlated with increased morbidity and mortality. They are risk factors.

Present-day medical dogma makes them biomarkers for cardiovascular disease, diabetes, bone fracture, in other words indicators of whether the disease is present. But that is tantamount to making those quantities measures of actual risk, in other words regarding them as measures of what causes those ailments, in other words equating risk factors with causes.

Official reports, however, as well as the many studies on which those reports are based, find that biomarkers are not proper measures of risk after all. See:

“Everyone is sick?”

“‘Hypertension’: An illness that isn’t illness”

“Cholesterol is good for you”

 

Unfortunately, they were not joking

“Magical statistics: Hearing loss causes dementia”

 

The overall lesson:

“Don’t take a pill if you’re not ill”

The ignorant acceptance of correlations as capable of demonstrating causation is greatly reinforced in medical matters by the pharmaceutical industry, which sells drugs as palliatives and preventatives based on nothing more than correlations with biomarkers.

Posted in conflicts of interest, consensus, media flaws, medical practices, prescription drugs | Tagged: , , , , , , , | 5 Comments »

Beyond Belief: Deadly vaccines for Africa and Asia

Posted by Henry Bauer on 2013/05/12

Here’s what’s known about Gardasil and Cervarix (see Deadly vaccines):
1. There’s no good evidence that they do anyone any good
2. There’s proof that they harm some people, at times even fatally

What then would one expect the manufacturers to do: Withdraw the vaccines?

Of course not. They would find a way to sell them despite the evidence:

Drugmakers, health groups bring poor girls vaccine (cr. AP, Linda A. Johnson)
“Two multinational drugmakers are teaming up with top global health groups to protect millions of girls in the world’s poorest countries from deadly cervical cancer.
Starting with pilot programs in eight Asian and African nations, the ambitious project ultimately is intended to inoculate more than 30 million girls in more than 40 countries by 2020. . . .
The endeavor was announced Thursday by the GAVI Alliance, a public-private partnership that’s worked with drugmakers to deliver affordable vaccines to poor countries to treat childhood illnesses that are big killers.”

The GAVI Alliance began as the “Global Alliance for Vaccines and Immunisation”. The name change may seem trivial, but it reflects the fact that it’s all about marketing and fund-raising; as with too many other “charities”, those who benefit most are the staff of the organization who enjoy well-paying jobs with ample benefits — for example, about 15% of salaries of GAVI staff are paid into retirement plans or accounts, amounting to about $4 million in 2011. If you can find in the GAVI Alliance Financial Reports  more information than that about how many employees there are, who they are, or what their compensation is, then you’re a better investigator than I am.
But what do the drug companies get out of this arrangement?

“Merck will supply its Gardasil for $4.50 per dose, and Glaxo its Cervarix for $4.60 per dose. In the U.S., the shots cost well over $100 apiece, and a three-dose series over six months is required. . . . .
The goal is for the governments of those countries to show they can set up a national system . . . to provide the vaccines over the long term . . .
Merck, based in Whitehouse Station, N.J., is providing 93 percent of the shots initially. It’s also agreed to provide more shots at an even-lower price in the future, if higher volumes of vaccines are ordered, as that would reduce production costs. . . .
In the U.S., the vaccines have become steady money makers since they were launched a half-dozen years ago, but they haven’t turned into the mega-sellers initially envisioned.”

I think it’s unlikely that Merck or Glaxo are planning to lose money on this. “Production costs” can be calculated in a number of different ways, of course, but I think one understands the present initiative best by looking at the marginal costs of producing more of these vaccines, in other words regarding the initial research and testing and marketing costs as done with and considering now only how much the actual cost of making more doses is. I would bet it’s less than $4.50-4.60 per dose.

But my disbelief at this initiative, and my cynicism and paranoia were aroused not only by the financial aspects. I was bemused — though not really surprised — to see the blatantly false claims of what these vaccines can prevent:
“The vaccines protect against the strains of human papilloma virus (HPV) . . . that most commonly cause cancer. The virus, transmitted during sex, causes cervical cancer as well as vaginal, vulvar, anal and oral cancers. The vaccines prevent roughly 70 percent of those cancers.”

There is no proof at all the vaccines prevent any cancer. All the evidence amounts to no more than that those strains of  HPV are often found in association with cervical cancer. That’s a correlation, which everyone should know is no proof of causation. The vaccines have not been in use for long enough for there to be any data about actually preventing cervical cancer.
As for “vaginal, vulvar, anal and oral cancers”, this was news to me, so I enquired further. And indeed the authorities do claim it to be so:

From the CDC:
“HPV types are often referred to as “low-risk” (wart-causing) or “high-risk” (cancer-causing), based on whether they put a person at risk for cancer.”
[This classification is guess-work. It is not known whether they cause cancer; everything is merely correlation]
”The International Agency for Research on Cancer found”
[NO: speculated]
”that 13 HPV types can cause cancer of the cervix; one of these types can cause”
[NO: pure speculation]
”cancers of the vulva, vagina, penis, anus, and certain head and neck cancers (specifically, the oropharynx, which includes the back of the throat, base of the tongue and tonsils). The types of HPV that can cause genital warts are not the same as the types that can cause cancer.
Most people who become infected with HPV do not know they have it. Usually, the body’s immune system gets rid of the HPV infection naturally within two years. This is true of both high-risk and low-risk types. By age 50, at least 4 out of every 5 women will have been infected with HPV at one point in their lives. HPV is also very common in men, and often has no symptoms” [emphasis added].
In other words, the risk from “high-risk” HPV is tiny at best. There are about 150 million women in the United States; so about 120 million (“4 out of every 5”)  had been infected with HPV at some time or other. In 2009, about 12,500 had been diagnosed with cervical cancer and 4000 died of it.

So the proportion of HPV-infected women
 who experience cervical cancer
 is 12,500/120,000,000 = 1/10,000 = 0.01%

When only 1 in 10,000 infected people experience illness, what sort of illness-causing infection is that?

As to cancers of “vulva, vagina, penis, anus, or the oropharynx (back of the throat, including the base of the tongue and tonsils)”; they “are much less common than cervical cancer. Much less is known about how many people with HPV will develop cancer in these areas.”
If they’re even less common, then of course their incidence is less than 0.01%.

***************************************************************************

This business illustrates once again how untrustworthy are the pronouncements of official institutions.

The only grounds for claiming HPV to be a cause of any cancers is that HPV has been found in some proportion of certain cancers. Such correlation does not amount to evidence that the virus causes those cancers. Indeed, the claim of causation becomes truly absurd when correlations are used to estimate what proportion of cancers are caused by infectious agents in general:
“The estimated total of infection-attributable cancer in the year 2002 is 1.9 million cases, or 17.8% of the global cancer burden. The principal agents are the bacterium Helicobacter pylori (5.5% of all cancer), the human papilloma viruses (5.2%), the hepatitis B and C viruses (4.9%), Epstein-Barr virus (1%), human immunodeficiency virus (HIV) together with the human herpes virus 8 (0.9%). Relatively less important causes of cancer are the schistosomes (0.1%), human T-cell lymphotropic virus type I (0.03%) and the liver flukes (0.02%)”
(D. M. Parkin, “The global health burden of infection-associated cancers in the year 2002”, International Journal of Cancer, 118(2006) 3030-44).
There is no actual proof of causation in any of those cases. Everything is calculated on the basis of correlations.
It’s worth recalling that the “war on cancer” declared in 1971 in the USA had funded unprecedented amounts of research by virologists searching for viral causes of human cancer; but they failed to find any at all (Peter Duesberg, Inventing the AIDS Virus [Regnery, 1996] chapter 3). Even before 1971, for some six decades some researchers had looked unsuccessfully for viral causes of human cancers after Peyton Rous had found a viral cause of chicken tumors.

Lack of substantive success in finding any human cancers demonstrably caused by a virus has now morphed into the declaration that viruses cause some proportion of cancers because they are sometimes found associated with those cancers. In other words, viruses cause cancer because correlation proves causation.
The only possible cure for this diseased interpretation might be to demand that every medical researcher be required to take an elementary course in probability and statistics during which they are required every day to write for several hours the phrase

CORRELATION NEVER PROVES CAUSATION

Posted in medical practices, science is not truth | Tagged: , , | 34 Comments »

 
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