Lipid hypothesis

Source: Wikipedia, the free encyclopedia.
This article is about the health risks of blood cholesterol. For the risks of saturated fat, see
Saturated fat and cardiovascular disease
.

The lipid hypothesis (also known as the

coronary heart disease".[1] It states, more concisely, that "decreasing blood cholesterol [...] significantly reduces coronary heart disease".[2]

As of 2023, there is international clinical acceptance of the lipid hypothesis.[3][4][5][6]

History

In 1856, the German

atherogenesis.[9]

Dutch physician

gallstones in Javanese people in 1916.[10][11] de Langen showed that the traditional Javanese diet, poor in cholesterol and other lipids, was associated with a low level of blood cholesterol and low incidence of cardiovascular disease (CVD), while the prevalence of CVD in Europeans living in Java on a Western diet was higher.[10] Since de Langen published his results only in Dutch, his work remained unknown to most of the international scientific community until the 1940s and 1950s.[10] By 1951, it was accepted that, although the causes of atheroma were still unknown, fat deposition was a major feature of the disease process. "The so-called fatty flecks or streaks of arteries are the early lesions of atherosclerosis and... may develop into the more advanced lesions of the disease."[12]

Ancel Keys and the Seven Countries Study

Ancel Keys

Main article: Ancel Keys

With the emergence of CVD as a major cause of death in the Western world in the middle of the 20th century, the lipid hypothesis received greater attention. In the 1940s, a University of Minnesota researcher,

heart attacks in middle-aged American men was related to their mode of life and possibly modifiable physical characteristics. He first explored this idea in a group of Minnesota business and professional men that he recruited into a prospective study in 1947, the first of many cohort studies eventually mounted internationally. The first major report appeared in 1963 and the men were followed through until 1981.[13] After fifteen years follow-up, the study confirmed the results of larger studies that reported earlier on the predictive value for heart attack of several risk factors: blood pressure, blood cholesterol level, and cigarette smoking.[13]

Seven Countries Study

Main article: Seven Countries Study

Keys presented his diet-lipid-heart disease hypothesis at a 1955 expert meeting of the

Time Magazine in that same year.[18]

The Seven Countries Study was formally started in fall 1958 in Yugoslavia. In total, 12,763 males, 40–59 years of age, were enrolled in seven countries, in four regions of the world (United States, Northern Europe, Southern Europe, Japan). One cohort is in the United States, two cohorts in Finland, one in the Netherlands, three in Italy, five in Yugoslavia (two in Croatia, and three in Serbia), two in Greece, and two in Japan. The entry examinations were performed between 1958 and 1964 with an average participation rate of 90%, lowest in the US, with 75%, and highest in one of the Japanese cohorts, with 100%.[19]

Keys' book Eat Well and Stay Well [20] popularized the idea that reducing the amount of saturated fat in the diet would reduce cholesterol levels and the risks of serious diseases due to atheroma.[21] Keys was followed during the rest of the 20th century by an accumulation of work that repeatedly demonstrated associations between cholesterol levels (and other modifiable risk factors including smoking and exercise) and risks of heart disease. These led to the acceptance of the lipid hypothesis as orthodoxy by much of the medical community.[22] By the end of the 1980s, there were widespread academic statements that the lipid hypothesis was proven beyond reasonable doubt,[23][24][25] or, as one article stated, "universally recognized as a law." [26][27][28][29][30]

Consensus

The medical consensus supports the lipid hypothesis as evidence from separate

LDL blood cholesterol are a significant risk factor for cardiovascular disease.[3]

The National Lipid Association have stated that by 2012, a wealth of evidence including numerous clinical trials examined by the Cholesterol Treatment Trialists' Collaboration has confirmed the lipid hypothesis.[31] Too much LDL (called "bad cholesterol") can lead to fatty deposits building up in the arteries, which increases the risk of cardiovascular disease. A 2017 consensus statement from the European Atherosclerosis Society concluded that "consistent evidence from numerous and multiple different types of clinical and genetic studies unequivocally establishes that LDL causes ASCVD."[3] The consensus statement noted:

Most publications that question the causal effect of LDL on the development of ASCVD tend to cite evidence from individual studies or a small group of highly selected studies, often without a quantitative synthesis of the presented evidence. Therefore, to avoid this type of selection bias, we have based our conclusions on the totality of evidence from separate meta-analyses of genetic studies, prospective epidemiologic studies, Mendelian randomization studies, and randomized clinical trials. This evidence base includes over 200 studies involving over 2 million participants with over 20 million person-years of follow-up and more than 150 000 cardiovascular events. Together these studies provide remarkably consistent and unequivocal evidence that LDL causes ASCVD.[3]

A review from the Journal of the American College of Cardiology in 2018 concluded:

The causal effect of LDL and other apo B–containing lipoproteins on the risk of cardiovascular disease is determined by both the magnitude and the cumulative duration of exposure to these lipoproteins. The goal of maintaining optimal lipid levels throughout life is to keep the concentration of circulating LDL and other apo B–containing lipoproteins low to minimize the number of particles that become retained in the arterial wall and thereby minimize the rate of progression of atherosclerotic plaques.[32]

The 2021

ApoB be used instead of LDL-C as the preferred lipid parameter for screening (Strong Recommendation, High-Quality Evidence)".[33]

The European Society of Cardiology have noted:

For almost a century, evidence has been overwhelming that lipids and diet are related and have a negative impact on CVD. It is also clear that lipids, and especially LDL, play a crucial role in atherosclerosis. However, groups of “non-believers” decelerated developments and clinical progress, sometimes for decades.[34]

In 2023, the World Heart Federation published a report which stated that high levels of low-density lipoprotein (LDL) cholesterol are a major risk factor for cardiovascular diseases and that elevated LDL cholesterol contributed to 3.8 million deaths in 2021.[6]

See also

References

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  2. PMID 16227628
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  3. ^
    PMID 28444290
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  4. PMID 26844337
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  5. PMID 35583875
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  6. ^ a b "World Heart Report 2023: Confronting the World's Number One Killer" (PDF). World Heart Federation. 2023. Retrieved 22 January 2024.
  7. ^ Virchow, Rudolf (1856). "Gesammelte Abhandlungen zur wissenschaftlichen Medizin". Vierteljahrschrift für die praktische Heilkunde. Germany: Staatsdruckerei Frankfurt. Phlogose und Thrombose im Gefäßsystem.
  8. PMID 15102877
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  9. PMID 23975896
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  10. ^
    PMID 22470931
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  11. ^ de Langen, Cornelis (1916). "Cholesterine-stofwisseling en rassenpathologie". Geneeskundig Tijdschrift voor Nederlandsch-Indie (in Dutch). 56: 1–34.
  12. PMID 14837929
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  13. ^
    PMID 14059458
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  14. ^ Famous Polemics on Diet-Heart Theory. Henry Blackburn, School of Public Health, University of Minnesota. http://www.epi.umn.edu/cvdepi/essay.asp?id=33 accessed 18 March 2014
  15. ISBN 978-0-674-80237-7
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  16. ^ Yerushalmy J, Hilleboe HE (1957). "Fat in the diet and mortality from heart disease. A methodologic note". NY State J Med. 57: 2343–54.
  17. PMID 14447694
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  18. ^ "TIME Magazine Cover: Ancel Keys". TIME.com. 13 January 1961. Retrieved 23 July 2017.
  19. ISBN 0-674-80237-3
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  20. ISBN 978-0-385-06575-7
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  21. ^ "Ancel Keys Obituary". The American Physiological Society. Archived from the original on 27 September 2007. Retrieved 15 April 2007.
  22. PMID 16585781
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  23. PMID 2676235
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  25. S2CID 30459713
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  26. S2CID 72257114
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  28. PMID 3304704
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  29. PMID 2073909
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  30. S2CID 7075128
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  31. ^ "The Lipid Hypothesis". lipid.org. Retrieved 22 January 2024.
  32. S2CID 52136486
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  33. PMID 33781847
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  34. ^ Kuijpers PM (13 January 2021). "History in medicine: the story of cholesterol, lipids and cardiology". e-Journal of Cardiology Practice. 18 (9).
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