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What do Your Cholesterol Numbers Mean?

A typical cholesterol blood test gives your readings for total blood cholesterol, HDL, LDL, Triglycerides and a ratio known as the cholesterol ratio. But what do the figures mean? A lot of people ask this question and I hope that this article will help to answer as least some of them.

The total cholesterol is the sum of all the cholesterol and this figure should ideally be equal or less than lower than 5.2 mmol/L (or 200 mg/dL).

LDL is also known as bad cholesterol and we want this to be low. Ideal reading is 2.6 mmol/L (or 100 mg/dL) or less. Anything higher and you will be told that it is not good. HDL is also known as good cholesterol and higher is good. Good numbers are above 1.04 mmol/L (or above 40 mg/dL) for men and above 1.29 mmol/L (or above 50 mg/dL) for women.

Triglycerides should be less than 1.7 mmol/L (or 150 mg/dL). High triglycerides level is a risk factor as it is usually associated with high LDL and low HDL. The mechanism of this association is not fully understood but high level of triglycerides is considered a risk factor for heart attack.

What is cholesterol ratio? It is the ratio of total cholesterol to HDL cholesterol. Research found the cholesterol ratio to be a good predictor of heart disease. You get this ratio by dividing the total cholesterol by the HDL and often this ratio is a more important indictor than total cholesterol alone. Why?

Studies show that people with fairly low cholesterol suffer heart attack. Yet some others with high total cholesterol do not. The mystery appears to be in the cholesterol ratio.

Let us take the example of John and Steve. John as a total cholesterol reading of 6.5 mmol/L and a HDL reading of 1.3 mmol/L. Steve on the other hand has a total cholesterol reading of 5.2 and a HDL reading of o.5 mmol/L.

Dividing John’s Total Cholesterol with HDL (6.5/1.3) we get a cholesterol ratio of 5. Dividing Steve’s Total Cholesterol with HDL (5.2/0.5) we get a cholesterol ratio of 10.4.

John has a higher total cholesterol reading and should be at a higher risk of a heart attack than Steve. But the reverse is true. Steve is actually at a higher risk. The important difference is the cholesterol ratio. Studies show that those with higher cholesterol ratio is at a greater risk that those with a low cholesterol ratio.

John should still try to bring his total cholesterol down by reducing LDL and triglycerides but as it stands his risk is lower than Steve.

The normal cholesterol ratio for men is 5 or lower while for women it is 4.5 or lower. Research tells us that 3.5 is good and less than 3 is excellent. Many studies show that a lower cholesterol ratio may actually protect the heart from an attack.

To recapitulate, the desire cholesterol numbers are:-

Total Cholesterol: < 5.2 mmol/L (<200 mg/dL)
HDL Cholesterol: > 1.04 (>40 mg/dL) for men
  > 1.18 (>50 mg/dL) for women
LDL Cholesterol: < 2.6 mmol/L (<100 mg/dL)
Triglycerides: <1.7 mmol/L (<150 mg/dL)
Cholesterol Ratio: < 5 for men
  < 4.5 for women

So pay attention. A famous US doctor once said that you need to remember four numbers to stay alive: your total cholesterol number, your HDL cholesterol number, your triglycerides and your Social Security number!

Note: In some countries cholesterol is measured in milligrams per deciliter (mg/dL). In other countries they are measured in millimols per liter (mmol/L). You can convert between them using the following conversion formulas.

For Cholesterol mg/dL of cholesterol x 0.02586 = mmol/L
  mmol/L of cholesterol x 38.67 = mg/dL
For Triglycerides mg/dL of cholesterol x 0.01129 = mmol/L
  mmol/L of cholesterol x 88.496 = mg/dL

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