Low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol measurement in Familial Dysbetalipoproteinemia

AIM

To compare LDL-C concentrations using the Friedewald formula, the Martin-Hopkins formula, a direct assay and polyacrylamide gradient gel electrophoresis (PGGE) to the reference standard density gradient ultracentrifugation in patients with Familial Dysbetalipoproteinemia (FD) patients. We also compared non-HDL-cholesterol concentrations by two methods.

METHODS

For this study data from 28 patients with genetically confirmed FD from the placebo arm of the EVOLVE-FD trial were used. Four different methods for determining LDL-C were compared with ultracentrifugation. Non-HDL-C was measured with standard assays and compared to ultracentrifugation. Correlation coefficients and Bland-Altman plots were used to compare the methods.

RESULTS

Mean age of the 28 FD patients was 62 ± 9 years, 43 % were female and 93 % had an ɛ2ɛ2 genotype. LDL-C determined by Friedewald (R² = 0.62, p <0.01), Martin-Hopkins (R² = 0.50, p = 0.01) and the direct assay (R² = 0.41, p = 0.03) correlated with density gradient ultracentrifugation. However, Bland-Altman plots showed considerable over- or underestimation by the four methods compared to ultracentrifugation. Non-HDL-C showed good correlation and agreement.

CONCLUSION

In patients with FD, all four methods investigated over- or underestimated LDL-C concentrations compared with ultracentrifugation. In contrast, standard non-HDL-C assays performed well, emphasizing the use of non-HDL-C in patients with FD.

Increased Non-High-Density Lipoprotein Cholesterol in Children and Young Adults with Turner Syndrome Is Not Explained By BMI Alone

BACKGROUND

Turner syndrome (TS) is associated with an increased risk of cardiovascular disease. Non-high-density lipoprotein cholesterol (non-HDL-C) is a convenient measure of atherogenicity (normal concentration <120 mg/dL) but has not been investigated in TS. We aim to evaluate non-HDL-C patterns in a cohort of pediatric and young adult females with TS.

METHODS

A retrospective chart review was used to obtain demographics, body composition, genetic reports, and lipid profiles in females with TS.

RESULTS

Lipid profiles were assessed in 158 females (mean age 13.6 years). Mean non-HDL-C was 118.9 mg/dL (±32.0); the prevalence of high non-HDL-C (≥144 mg/dL) was 17.7% (n = 28). In TS females aged 8-17 years (n = 46), the prevalence of high non-HDL-C was 23.9% (95% CI 11.1-36.7; n = 11) between 2011 and 2012, compared to 9.2% (95% CI 5.6-14.1) in females of the same age in the general population reported in the National Health and Nutrition Examination Survey (NHANES) dataset (p < 0.005). Body mass index (BMI) accounted for only 6% of variance in non-HDL-C values (β coefficient = 1.31, p < 0.05).

CONCLUSIONS

Children and adolescents aged 8-17 years with TS appear to have a greater prevalence of adverse non-HDL-C levels compared to the general adolescent population. The prevalence of high non-HDL-C was not fully explained by BMI.