Why is your HDL higher than your LDL?

High Total Cholesterol vs. low LDL/HDL Ratio???

• Which is the biggest indicator of problems or risk? * The Total Cholesterol number or, * The ratio of LDL/HDL How is the Total Cholesterol number calculated? (No matter what numbers I add up on a lab report, I cannot duplicate the number) What may be some valid reasons for why a Total Cholesterol Number (say 286 but an extremely low ratio for LDL to HDL, say 1.2, a ratio that places a woman in the 1/2 average risk range) might cause an insurance company to either rate up or deny coverage - based on the Total number without regard to the low risk ratio? It appears that the ratio of LDL to HDL is the more important number but my questions to insurance companies and research on the Internet has not led me to any sort of an answer. Can you help?

• Answer:

  Hello, Thanks for asking your question. 1) Which is the biggest indicator of problems or risk? * The Total Cholesterol number or, * The ratio of LDL/HDL Both are associated with cardiac risk. However, the LDL/HDL ratio is a bigger indicator. The components of a measured total cholesterol (LDL, HDL, triglycerides) includes HDL ("good" cholesterol) which correlates inversely with cardiac risk. From Best Practice of Medicine: "Although useful in screening large populations for dyslipidemias, serum cholesterol cannot be considered the sole measure of risk for CHD attributable to serum lipids. This is based on our current understanding of lipoprotein cholesterol subfractions and the availability of standardized laboratory methods to measure them in clinical practice. Serum total cholesterol tends to index low-density-lipoprotein (LDL) cholesterol, which varies directly with CHD risk (Figure 6) and is considered atherogenic. High-density-lipoprotein (HDL) cholesterol varies inversely with CHD incidence and is considered anti-atherogenic or protective." http://merck.micromedex.com/bpm/bpm.asp?page=CPM02CA335§ion=report&ss=2 Here is a definition of the LDL/HDL ratio: "Another ratio is LDL/HDL. The LDL/HDL ratio is actually a more pure ratio than total cholesterol/HDL. Because LDL is a measure of bad cholesterol and HDL is a measure of good cholesterol, whereas the total cholesterol is the sum of HDL, LDL, and the VLDL. Yes, adding up the HDL, LDL and VLDL makes up the total cholesterol measurement." http://my.cardiovalens.com/featured/featuredisplay.asp?featureid=155 The data from studies suggests that the LDL/HDL ratio is more predictive of cardiac risk: "Data from the Lipid Research Clinics and the Framingham Heart Study suggest that the total cholesterol (or LDL-cholesterol)-to-HDL-cholesterol ratio may have greater predictive value for CHD than serum total or LDL-cholesterol . . . In contrast, serum total or LDL-cholesterol did not add independent predictive value to the ratio." (1) 2) How is the Total Cholesterol number calculated? This is derived from the Friedewald formula for LDL cholesterol: LDL-cholesterol = Total cholesterol - (triglycerides/5) - HDL-cholesterol Thus, doing some basic algebra: Total cholesterol = LDL-cholesterol + HDL-cholesterol + (triglycerides/5) 3) What may be some valid reasons for why a Total Cholesterol Number (say 286 but an extremely low ratio for LDL to HDL, say 1.2, a ratio that places a woman in the 1/2 average risk range) might cause an insurance company to either rate up or deny coverage - based on the Total number without regard to the low risk ratio? I cannot say for sure since I don't work for any insurance companies, but I can hypothesize it is because of the triglycerides. What is not accounted for in a LDL/HDL ratio is the triglycerides (i.e. fat content in the blood). Even though the ratio is low, the fact that the total cholesterol is high suggests that the triglycerides are high. High triglycerides are a negative predictor of cardiac risk. From UptoDate: "Hypertriglyceridemia is associated with an increased risk for cardiovascular disease . . . In the Physician's Health Study, the risk of myocardial infarction (MI) was highest among men with the highest tertile for both triglyceride and the TC/HDL-C ratio." (2) From Best Practice of Medicine: "Data from several studies, including the Framingham Study, suggest that serum triglycerides may be important predictors for CHD in men or women, but not consistently in both sexes. Despite these observations, the current consensus holds that elevated levels of serum triglycerides represent a risk marker for obesity, glucose intolerance, and low HDL levels, all of which confer risk for CHD and, to the extent possible, deserve preventive attention." http://merck.micromedex.com/bpm/bpm.asp?page=CPM02CA335§ion=report&ss=2 Please use any answer clarification before rating this answer. I will be happy to explain or expand on any issue you may have. Thanks, Kevin, M.D. Internet search strategy: No internet search engine was used in this research. All sources were from objective physician-written and peer reviewed sources. Bibliography: 1) Kinosian, B, Glick, H, Garland, G. Cholesterol and coronary heart disease: Predicting risks by levels and ratios. Ann Intern Med 1994; 121:641. 2) Stampfer, MJ, Krauss, RM, Ma, J, et al. A prospective study of triglyceride level, low-density lipoprotein particle diameter, and risk of myocardial infarction. JAMA 1996; 276:882. Links: Best Practice of Medicine - Cardiac Risk Factors http://merck.micromedex.com/bpm/bpm.asp?page=CPM02CA335§ion=report&ss=2 Cardiovalens.com - Cardiac Risk Factors http://my.cardiovalens.com/featured/featuredisplay.asp?featureid=155