Cholesterol & Heart Disease: Part 1

Cholesterol is a word everyone is familiar with today.  When we have our blood drawn, the number next to our “Total Cholesterol” or “TC” is usually of great interest to our doctor, particularly if it’s deemed “high.” That is also the case with our “LDL,” which is considered to be the “bad cholesterol.” So what has been conventionally accepted as high?

 

Total Cholesterol                                

              HIGH                                                       

>200 mg/dl
LDL
>160 mg/dl (if you have low risk1 for heart disease)
>130 mg/dl (if you have intermediate risk2  for heart disease)
>100 mg/dl (if you have high risk3 for heart disease)

*1. If you’re a nonsmoker AND nondiabetic AND nonoverweight AND no family history of premature heart disease AND TC <200   mg/dl AND HDL >40 mg/dl AND Blood Pressure  <120/80

*2. If you’re not high or low risk

*3. If you already have Heart Disease OR other Vascular Disease OR Type 2 Diabetes OR >65 years + >1 risk factor

 

Today, Heart Disease is the #1 cause of death in the United States. According to these guidelines, if one has high TC or LDL levels, then they are increasing their risk for heart disease. But is this really true? In this series, I’m going to explore some of the most commonly held notions about the relationship between diet, TC, LDL, and causes of heart disease.
#1: If your total cholesterol is greater than 200 mg/dl, you have an increased risk of heart disease.
Many studies have been conducted to explore the relationship between TC levels and heart disease. However, there is one study that has served as the main pillar: The Framingham Heart Study. This study was initiated by the Unites States Public Health Service in 1948, which looked at 5,209 adults from Framingham, Massachusetts to investigate the epidemiology and risk factors for heart disease. Before this study, doctors generally did not believe in the concept of risk factors for developing heart disease. They believed it was just a natural consequence of aging. One of the conclusions drawn from this study was that the higher your cholesterol levels were, the higher your risk for developing heart disease.
Since then, it has been accepted by the medical community as backbone evidence to express strong caution to patients that have high cholesterol.
However, this evidence was not true. Let’s look at a graph that compared people who got heart disease, to the ones who didn’t1:

 

 

  • The average cholesterol level in a patient who got heart disease was >200. The average cholesterol level in a patient who didn’t get heart disease was >200
  • The cholesterol distribution of people who developed heart disease and did not, was very similar. For example: 
 -TC of 180 mg made up almost the same portion of people who got CHD as the ones who didn’t
 -TC of 220 mg made up almost the same portion of people who got CHD as the ones who didn’t
 -TC of 340 mg made up almost the same portion of people who got CHD as the ones who didn’t
  • 100% of people with a TC >380 mg had heart disease
  • 100% of people with a TC <150 mg did not have heart disease
  • 90% of people with a TC 220 mg did not have heart disease
This shows that there isn’t a direct relationship between TC & heart disease. You’re at a 10-20% risk of getting heart disease if you’re total cholesterol is >150 <380. This risk goes to 0% when your TC <150 mg. But can you really be free of heart disease if your total cholesterol is less than 150 mg/dl? As Dr. Paterson in his 1963 study commented about one of his patients2: “Over a 9-year period, this man consistently showed a serum cholesterol level of less than 145 mg. per cent. The mean level was 111 mg. per cent. In our experience this is an extraordinarily low value; nevertheless, a severe grade of coronary sclerosis was demonstrated at autopsy…….it is important to note that he was hypertensive as well as having controlled diabetes.”
Risk factors such as diabetes, hypertension, smoking, and being overweight, can cause heart disease regardless of TC level.  It must also be considered when looking at the 10-20% risk of heart disease in TC >150. This graph included subjects who had one or more of these risk factors.  For example, diabetic men were twice more likely to develop heart disease, even though their average cholesterol level with heart disease (239 mg%) were similar to nondiabetics with heart disease (244 mg%)3. Meaning, the 10-20% risk of getting heart disease could be reduced to  5-10% in nondiabetic  people who’s TC > 150 <380. If one takes into account the other risk factors such as smoking, hypertension, and being overweight, then this risk could very well go to 0%.
Proponents of the cholesterol-heart disease connection point to the relationship between total cholesterol and mortality in the Framingham Study. Indeed, a positive relationship was found between TC and mortality in age <50 years. Let’s take a look at this4:

 

 

But here is the problem: 80% of people who die from heart disease are 65 years or older. Meaning at most, this relationship points only to the 20% of people who die from heart disease5. Youth-Onset Type 2 Diabetes can significantly increase the risk of death at <65 years of age6. Interestingly, the significant increase in deaths occurs when the cholesterol jumps to 240 mg/dl—practically identical to the average cholesterol level of diabetics who got heart disease in this study.  Thus, Youth-Onset Type 2 Diabetes can confound the relationship between cholesterol & mortality in this age bracket.  
Have other studies showed a relationship between TC & heart disease? In 1966, a study published by Dr. Paulin looked at the relationship between lipids and coronary angiographic changes. Interestingly, Dr. Paulin was also a pioneer in Coronary Angiography. Let’s take a look at the graph that compared cholesterol levels to coronary changes (suggesting heart disease)7:

 

 

  • Many patients with a TC >281 mg% had no coronary changes
  • There were no significant coronary changes between patients with a TC >281 mg% compared to patients with a TC <280 mg%

 

What about age? The age group of males in this study was 26-67 years old. Many proponents of the cholesterol-heart disease relationship will claim that as one gets older, their cholesterol level will go down—skewing the relationship. After all, wasn’t it in the <50 years age group that the Framingham Study “showed” a direct relationship between total cholesterol and mortality? However, this does not explain the results of this study.
Countless studies have shown that cholesterol levels increase up to the age of 65 in males. Even then, cholesterol does not decrease significantly until age 70+8. This not only does not explain the lack of relationship between cholesterol & heart disease in Dr. Paulin’s study, but also, why there wasn’t a relationship between cholesterol & mortality in the 60 years age group in the Framingham Study?
Part 1 of this series shows that:
1. There is no “magic” total cholesterol level to be free of heart disease
2. Increased age does not explain the similar total cholesterol distribution between patients who get heart disease and don’t
3. There is no relationship between total cholesterol levels and heart disease

 


 

 

References

1. Kannel WB, Castelli WP, Gordon T.  Cholesterol in the Prediction of Atherosclerotic Disease.  New Perspectives Based on the Framingham Study.  Ann Intern Med. 1979;90(1):85-91.

2. Paterson JC, Armstrong R, Armstrong EC. Serum Lipid Levels and the Severity of Coronary and Cerebral Atherosclerosis in Adequately Nourished Men, 60 to 69 Years of Age. Circulation. 1963 Feb;27:229-36.

3. Kannel WB, McGee DL. Diabetes and Cardiovascular Risk Factors: The Framingham Study. Circulation. 1979;59:8-13

4.  Guyenet, Stephan. The Diet-Heart Hypothesis: A Little Perspective. http://wholehealthsource.blogspot.com/2009/07/diet-heart-hypothesis-little.html

5. Go AS, Mozaffarian D, Roger VL, Benjamin EJ, BerryJD, Borden WB, Bravata DM, Dai S, Ford ES, Fox CS, Franco S, Fullerton HJ, Gillespie C, Hailpern SM, Heit JA, Howard VJ, Huffman MD, Kissela BM, Kittner SJ, Lackland DT, Lichtman JH, Lisabeth LD, Magid D, Marcus GM, Marelli A, Matchar DB, McGuire DK, Mohler ER, Moy CS, Mussolino ME, Nichol G, Paynter NP, Schreiner PJ, Sorlie PD, Stein J, Turan TN, Virani SS, Wong ND, Woo D, Turner MB; on behalf of the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics—2013 update: a report from the American Heart Association. Circulation. 2013;127:e6-e245.

6. Constantino MI. Long-term complications and mortality in young-onset diabetes: type 2 diabetes is more hazardous and lethal than type 1 diabetes. Diabetes Care. 2013 Dec;36(12):3863-9.

7. Cramer K, Paulin S, Werko L. Coronary Angiographic Findings in Correlation with Age, Body Weight, Blood Pressure, Serum Lipids, and Smoking Habits. Circulation. 1966;33:888-900

8. Total, LDL, and HDL Cholesterol Decrease With Age in Older Men and Women: The Rancho Bernardo Study 1984 1994. Circulation 1997 96:(1) 37-43.

 

 

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