Submitted to: Clinica Chimica Acta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/1996
Publication Date: N/A
Citation: Interpretive Summary: Cholesterol and triglyceride are two fats carried in the blood on various particles known as lipoproteins. The major cholesterol-carrying particle is called low density lipoprotein, or LDL. There is another particle that is similar to LDL, but which has a protein known as apo(a) attached to it. This particle, or lipoprotein, is known as lipoprotein(a), or Lp(a). Levels of Lp(a) are almost entirely determined by genetics, and higher levels have been associated with early heart disease. Our purpose was to develop normal ranges for Lp(a) and to examine the effects of age, gender, and menopause on Lp(a) levels in participants in the Framingham Offspring Study through using a commercially available test (or assay) that can measure such levels. We carried out these studies on 1949 women and 1884 men. Values of over 500 mg/l were associated with a high risk of heart disease. This value corresponded approximately to the 90th percentile for both men and women. Mean Lp(a) values were 200 mg/l in men and 214 mg/l in women, so women had modestly, but significantly, higher values than men. These data provide normal ranges and cutoff points for the prediction of heart disease risk using a commercially available assay for Lp(a).
Technical Abstract: The purpose of our research was to evaluate a commercially available, automated, immunoturbidimetric assay for lipoprotein(a) (Lp(a)), to determine the distribution of Lp(a) in the Framingham Offspring Study population, and to determine Lp(a) levels that may be useful for assessing coronary heart disease risk. The mean between-run coefficient of variation for this assay was 5.65%. Lp(a) concentration was slightly, but significantly, higher in 1949 white women (mean +/- S.D. 214 +/- 195 mg/l, median 150 mg/l) than in 1884 white men (mean +/- S.D. 200 +/- 193 mg/l, median 130 mg/l) participating in Cycle 4 of the Framingham Offspring Study (P = 0.0015). Lp(a) values of 300 mg/l and 500 mg/l corresponded to approximately the 75th and 90th percentiles, respectively, for both men and women, and subjects with concentrations greater than or equal to 500 mg/l were more likely to have coronary heart disease than subjects with an Lp(a) concentration less than 300 mg/l (P < 0.05 for men).