HDS-20.1 Data Details

Most of the circulating cholesterol is found in three major lipoprotein fractions: very low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). LDL cholesterol is calculated from measured values of total cholesterol, triglycerides, and HDL cholesterol according to the Friedewald calculation: [LDL cholesterol] = [total cholesterol] - [HDL cholesterol] - [triglycerides/5] where [triglycerides/5] is an estimate of VLDL cholesterol and all values are expressed in mg/dL.

LDL carries most of the circulating cholesterol and, when elevated, contributes to the development of coronary atherosclerosis. LDL- cholesterol is measured to assess risk for CHD and to follow the progress of patients being treated to lower LDL cholesterol concentrations.

Desirable levels of LDL cholesterol are below 100 mg/dL; borderline low from 100-129 mg/dL; borderline high is from 130-159 mg/dL; high is from 160-189 mg/dL; and very high LDL- cholesterol is greater than or equal to 190 mg/dL.

Coronary heart disease is defined based on a health care professional's diagnosis of coronary heart disease, angina, or heart attack (also called myocardial infarction) or meeting the criteria for grade 1 angina by the Rose questionnaire assessment. The Rose questionnaire is only administered to survey participants aged 40 years and over. Grade 1 angina is defined based on a positive response to ever having had pain or discomfort in chest and ever getting pain or discomfort in chest when walking up hill or in a hurry (but not getting pain or discomfort in chest when walking at an ordinary pace on level ground) and stopping or slowing down if get it while walking and pain or discomfort relieved when standing still, and pain relieved in 10 minutes or less, plus either pain or discomfort located in upper sternum, lower sternum, or left chest and left arm.