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The functional properties of the apolipoproteins (apoB and apoA-I) governing lipoprotein metabolism make these variables conceptually important as markers for coronary artery disease risk. This aspect was examined in a biracial (black-white) population of children as part of the Bogalusa Heart Study. White children, especially boys, showed lower concentrations of apoA-I and ratios of cholesterol to apoB within low-density lipoprotein (LDL) than did black children. Persistence of apoB concentrations over time, coupled with its strong linkage with apoB gene locus, underscores the value of detecting apoB excess early in life. Further, the impact of apoE genotypes on apoB and apoA-I levels is already evident in childhood. We found that, as a screening test for detecting increased LDL cholesterol, apoB is superior to total cholesterol. Low values for apoA-I concentration, the apoA-I to apoB ratio, and LDL cholesterol to apoB ratio in children are strongly related to parental incidence of myocardial infarction; no such relationship is seen with respect to lipoprotein cholesterols. Thus, expanding screening strategies might be useful for identifying individuals with adverse apolipoprotein profiles early in life.

We separately evaluated split specimens of serum for lipoprotein cholesterol in 38 five- to 14-year-old children, by the heparin/Ca2+ precipitation method and the ultracentrifugation/dextran sulfate precipitation method. Statistical analysis of the results indicated an excellent agreement (especially in beta- and alpha-lipoprotein cholesterol values) between results by the two methods. The percentage of alpha-lipoprotein cholesterol (mean +/- SD: 38.6 +/- 5.0) in children further confirmed the earlier observations that cholesterol derived from alpha-lipoprotein in children constitutes a relatively greater part of the serum total cholesterol than is true of adults.

We evaluated glycosylation of hemoglobin (HbA + HbA1) in 25 control subjects and in 133 diabetic patients who were in various stages of blood glucose control, by measuring ketoamine-linked hexoses in hemoglobin. These hexoses were converted by digestion with 10 mol/L acetic acid for 16 h at 100 +/- 5 degrees C to 5-hydroxymethylfurfuraldehyde, which was quantitated by reaction with 2-thiobarbituric acid. Glycosylation of hemoglobin was expressed as micromoles of hydroxymethylfurfuraldehyde per gram of globin protein (the "HMF index"). A mean HMF index of 1.67 (SD = 0.23) was obtained for controls; that for diabetic patients was 2.93 (SD 0.95). The index correlated well (r = 0.83, p < 0.001) with average blood glucose concentration as measured during the preceding 16 weeks, over a wide range of glucose values (1 to 6 g/L). It correlated even better (r = 0.92, p < 0.001) when corrected for variations in hemoglobin concentration. Thus measurement of ketoamine-linked hexoses of hemoglobin or HMF index provides an independent and useful alternative to the currently used methods that measure only HbA1 or HbA1c.

We used a combination of heparin micro-affinity column chromatography and heparin-Mn2+/dextran sulfate (DS) precipitation procedures to measure directly the total high-density lipoprotein (HDL)-cholesterol and HDL3-cholesterol in serum. The value for HDL2-cholesterol was obtained by subtracting the value for HDL3-cholesterol from that for total HDL-cholesterol. Results of this methodology and of the original heparin-Mn2+/DS double-precipitation method were compared with those of preparative ultracentrifugation. Concentrations of HDL- and HDL2-cholesterol by the original double-precipitation method were respectively 26 and 33 mg/L lower than by the ultracentrifugation method (p less than 0.001). Corresponding values by the micro-affinity/precipitation method were 36 and 29 mg/L higher than by the ultracentrifugation method (p less than 0.001). The values for HDL3-cholesterol by ultracentrifugation and by precipitation differed only by 7 mg/L (p greater than 0.05). Micro-affinity/precipitation and double-precipitation results both correlated well with those by ultracentrifugation (r = 0.84 to 0.94); the y-intercept of the comparison with the micro-affinity/precipitation method was close to zero. Use of the micro-affinity/precipitation method with samples from black or white adolescents showed that the blacks had higher concentrations of HDL2-(p less than 0.01) and HDL3-cholesterol (p less than 0.02) than did the whites.

We evaluated glycosylation of hemoglobin (HbA + HbA1) in 25 control subjects and in 133 diabetic patients who were in various stages of blood glucose control, by measuring ketoamine-linked hexoses in hemoglobin. These hexoses were converted by digestion with 10 mol/L acetic acid for 16 h at 100 +/- 5 degrees C to 5-hydroxymethylfurfuraldehyde, which was quantitated by reaction with 2-thiobarbituric acid. Glycosylation of hemoglobin was expressed as micromoles of hydroxymethylfurfuraldehyde per gram of globin protein (the "HMF index"). A mean HMF index of 1.67 (SD = 0.23) was obtained for controls; that for diabetic patients was 2.93 (SD 0.95). The index correlated well (r = 0.83, p0.001) with average blood glucose concentration as measured during the preceding 16 weeks, over a wide range of glucose values (1 to 6 g/L). It correlated even better (r = 0.92, p0.001) when corrected for variations in hemoglobin concentration. Thus measurement of ketoamine-linked hexoses of hemoglobin or HMF index provides an independent and useful alternative to the currently used methods that measure only HbA1 or HbA1c.

We compared serum lipoprotein cholesterol concentrations in a randomly selected subsample (n = 406) population of children (ages 5 to 17 years), as measured by the heparin-Ca2+ and the heparin-Mn2+ precipitation methods. Statistical analysis showed significant differences between results by these methods, especially in values for VLDL- and HDL-cholesterol (mean difference: VLDL-cholesterol, -61 mg/L; HDL-cholesterol, + 108 mg/L). Lipoprotein electrophoretic data indicated that estimating VLDL-cholesterol from serum triglyceride concentrations invariably resulted in higher values for children with an extremely faint pre-beta-lipoprotein band. Among the HDL-subfractions, 14 to 20% of HDL2 was precipitated by heparin-Mn2+ despite the presence of 80 g of albumin per liter. Heparin affinity chromatography of HDL2 in the presence of Ca2+ and Mn2+ showed an interaction of apolipoprotein E-containing HDL2 subfraction only in conditions involving Mn2+. The heparin-Ca2+ procedure precipitated the equivalent of 2 g of beta- plus pre-beta-lipoprotein cholesterol per liter from serum, with no detectable apolipoprotein B in the supernate. We conclude that these precipitations are affected by cation specificity and by differences in lipoprotein makeup of a given individual or population group.

We separately evaluated split specimens of serum for lipoprotein cholesterol in 38 five- to 14-year-old children, by the heparin/Ca2+ precipitation method and the ultracentrifugation/dextran sulfate precipitation method. Statistical analysis of the results indicated an excellent agreement (especially in beta- and alpha-lipoprotein cholesterol values) between results by the two methods. The percentage of alpha-lipoprotein cholesterol (mean +/- SD: 38.6 +/- 5.0) in children further confirmed the earlier observations that cholesterol derived from alpha-lipoprotein in children constitutes a relatively greater part of the serum total cholesterol than is true of adults.

We compared the serum lipoprotein cholesterol concentrations in subgroups of children (n = 360), ages 5-17 years, as measured by the heparin-Ca2+ and preparative ultracentrifugation methods. Children were grouped from the total population on the basis of their previous results for serum beta- and pre-beta-lipoprotein cholesterol (Group I: low beta- and low pre-beta-; Group II: high beta- and low pre-beta; Group III: high beta- and high pre-beta-; Group IV: low beta- and high pre-beta-). The values for very-low-density (VLDL) cholesterol by ultracentrifugation method were 44, 53, 15, and 10 mg/L greater than the values for pre-beta-lipoprotein cholesterol by the heparin-Ca2+ method in Groups I, II, III, and IV, respectively; the differences were not significant in Group IV. The values of low-density (LDL) cholesterol were 64, 137, 144, and 73 mg/L less than the values for beta-lipoprotein cholesterol in Groups I, II, III, and IV, respectively (p less than 0.005). On the other hand, high-density (HDL) cholesterol concentrations in the respective four groups were 10, 37, 93, and 52 mg/L greater than alpha-lipoprotein cholesterol concentrations; the differences were significant for Groups II, III, and IV (p less than 0.005). Overall, the values for LDL-cholesterol correlated highly with beta-lipoprotein cholesterol (r = 0.94), whereas correlations for VLDL- and HDL-cholesterol values with pre-beta-lipoprotein cholesterol (r = 0.76) and alpha-lipoprotein cholesterol (r = 0.77) were somewhat lower. The differences between these two methods may result from their different operational definitions for measuring serum lipoproteins and the possibility that without appropriate corrections the values obtained by preparative ultracentrifugation do not serve as reference values.

Clinical and anatomical observations from the Bogalusa Heart Study over a 15-year span provide data on cardiovascular risk factors and the early natural history of arteriosclerosis. These studies established that: cardiovascular risk can be predicted in early life; interrelationships of risk factors in children are similar to those observed in adults; and concentrations of serum lipoproteins change during sexual maturation. Strategies involving the general population and high-risk groups should be considered to help reduce atherosclerosis and coronary artery disease. Active modification of risk factors in the general populace would include using such methods as screening, education, and mass-media campaigns. Educational promotion ("Heart Smart") has already been implemented in the New Orleans area, focusing on using the total school environment to teach cardiovascular health and to encourage children to adopt desirable lifestyles. Inclusion of cardiovascular health education into general educational studies of children should be a major objective of the future.

We evaluated the variability in total cholesterol concentrations in serum in a large population of children over a period of time, to help us discern the limitations in reliability of current clinical laboratory methods for its analysis. We analyzed sera from a population of approximately 4000 children over a four-year period, quality-control sera, pooled sera, and surveillance samples from the Centers for Disease Control over a seven-year period, with a Technicon AutoAnalyzer II. Two methods of correction were suggested to adjust deviations in yearly serum total cholesterol means: yearly screening data were corrected on the basis of monthly variability in pooled-serum determinations and on the basis of deviations from values suggested by the Centers for Disease Control. Both correction methods were insufficient. These changes occur very slowly, and unless there is close monitoring and frequent comparison with a known standard, changes in laboratory results still can occur.