The Cholesterol Correlation – Correlation and Causation

The Cholesterol Correlation – Correlation and Causation

The decline in mortality rates caused by infectious diseases during the first half of the 20th century resulted in a very significant improvement in life expectancy.

UK Deaths by Age
Mortality in England and Wales: Average Life Span, 2010
http://www.ons.gov.uk/ons/rel/mortality-ageing/mortality-in-england-and-wales/average-life-span/rpt-average-life-span.html

This improvement in life expectancy meant that death became increasingly associated with other causes such as heart disease.

UK Deaths - Coronary Heart Disease

Sex matters: Secular and geographical trends in sex differences in coronary heart disease mortality
D A Lawlor, S Ebrahim and G Davey Smith – BMJ – 8 September 2001
http://www.bmj.com/content/323/7312/541

The resultant changes in the cause of death statistics can be interpreted as being caused by an “epidemic of heart disease”.

At the beginning of the 20th century, the 3 leading causes of death in the United States were infectious diseases – pneumonia, tuberculosis, and diarrhea – which in combination claimed 539 lives per 100 000.

Lurking in the background as the fourth leading cause of death was heart disease (137 deaths per 100 000).

But this would change.

With life expectancy of only 47 years at the beginning of the century, people did not live long enough for heart disease to claim many lives.

With the advent of the electrocardiogram to facilitate the diagnosis of heart disease, antibiotics to treat infectious diseases, and increasing life expectancy, the number and proportion of deaths due to heart disease soared.

During the Great Depression, the number of deaths due to heart disease was twice that of the next leading cause of death (pneumonia).

In 1945, at the time of President Roosevelt’s fatal brain hemorrhage due to decades of uncontrolled hypertension, heart disease accounted for more deaths in the United States than the next 3 causes combined.

Deaths due to heart disease peaked in 1968 at 374 per 100 000.

Combating the Epidemic of Heart Disease
Daniel Levy – 2012 – Journal of the American Medical Association
http://jama.jamanetwork.com/article.aspx?articleid=1487483

Therefore, during the 1950s, the focus of attention turned towards preventing “degenerative heart disease”.

But the need for major public health attention is clear whenever two conditions exist:

First, when there are large numbers of the population suffering disability and death from diseases against which private medical practise is making little headway.

And, second, when there is any reason to hope that the incidence of these diseases may be altered by measures applicable to the general population, even if these measures are not yet known.

Degenerative heart disease fulfils these conditions.

It is unnecessary to cite the mournful facts about the great numbers of persons, and by no means merely the aged, who are affected.

And everyone must admit that the present practice and progress of diagnostic and therapeutic medicine is not solving the problem; the proof is only too clear in our vital statistics.

Atherosclerosis: a problem in newer public health – Ancel Keys
Journal of Mount Sinai Hospital NY 1953; 20:118-39
http://originaleating.org/files/Keys,_Atherosclerosis,_A_Problem_in_Newer_Public_Health.pdf

However, before “degenerative heart disease” can be prevented the cause [or causes] of “degenerative heart disease” must be successfully identified.

Causality (also referred to as causation) is the relation between an event (the cause) and a second event (the effect), where the second event is understood as a physical consequence of the first.

https://en.wikipedia.org/wiki/Causality

Correlation does not imply causation is a phrase used in science and statistics to emphasize that a correlation between two variables does not necessarily imply that one causes the other.

https://en.wikipedia.org/wiki/Correlation_does_not_imply_causation

Fires

This was [and remains] a very difficult task because so many factors have been correlated with heart disease during the 20th century.

Firstly, heart disease has been correlated with smoking.

Heart Disease in London

Ischaemic heart disease, aortic aneurysms, and atherosclerosis in the City of London, 1868-1982.
R. Finlayson
Med Hist Suppl. 1985; (5): 151–168.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2557402/

Secondly, heart disease has been correlated with dietary fat.

Dietary Fat

Atherosclerosis: a problem in newer public health – Ancel Keys
Journal of Mount Sinai Hospital NY 1953; 20:118-39
http://originaleating.org/files/Keys,_Atherosclerosis,_A_Problem_in_Newer_Public_Health.pdf

Secondly, heart disease has been correlated with the number of television and radio licences.

Radio and Television

Pure, White and Deadly – John Yudkin – 1972 – Penguin Book

Fourthly, heart disease has been correlated with sugar consumption.

Sugar Consumption

Pure, White and Deadly – John Yudkin – 1972 – Penguin Book

Therefore, statistical correlations do not provide the necessary information to identify the cause [or causes] of heart disease.

The questionable cause – also known as causal fallacy, false cause, or non causa pro causa (“non-cause for cause” in Latin) – is a category of informal fallacies in which a cause is incorrectly identified.

https://en.wikipedia.org/wiki/Questionable_cause

Sadly, this basic statistical truth has been ignored in many influential studies…

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2 Responses to The Cholesterol Correlation – Correlation and Causation

  1. gymnosperm says:

    My own pet peeve is Sodium. Dietary Sodium is highly correlated with hypertension, yet it has been well known to researchers since the seventies that it is actually the Chlorine in table salt causing the hypertension. Nevertheless we are counseled low sodium diets.

  2. kuhnkat says:

    gymnosperm, there is no correlation between salt and hypertension.

    http://ajh.oxfordjournals.org/content/26/10/1218.long
    http://www.nap.edu/catalog.php?record_id=18311

    If salt isn’t correlated, how could you eat enough vegetables to get too much chloride??

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