The triglyceride/high-density lipoprotein cholesterol ratio fails to predict insulin resistance in African-American women: an analysis of Jackson Heart Study

• Published in: Metabolic syndrome and related disorders Vol. 8; no. 6; p. 511
• Main Authors: Sumner, Anne E, Harman, Jane L, Buxbaum, Sarah G, Miller, 3rd, Bernard V, Tambay, Anita V, Wyatt, Sharon B, Taylor, Herman A, Rotimi, Charles N, Sarpong, Daniel F
• Format: Journal Article
• Language: English
• Published: United States 01.12.2010
• Subjects: Adult; African Americans - statistics & numerical data; Aged; Aged, 80 and over; Body Mass Index; Cholesterol, HDL - blood; Cholesterol, HDL - metabolism; Cohort Studies; Coronary Disease - blood; Coronary Disease - diagnosis; Coronary Disease - ethnology; Coronary Disease - metabolism; Female; Humans; Insulin Resistance - physiology; Male; Middle Aged; Mississippi; Prognosis; Triglycerides - blood; Triglycerides - metabolism; Mississippi
• ISSN: 1557-8518
• DOI: 10.1089/met.2010.0028

Compared to whites, insulin-resistant African Americans have worse outcomes. Screening programs that could identify insulin resistance early enough for intervention to affect outcome often rely on triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) levels. Racial differences in TG and HDL-C may compromise the efficacy of these programs in African Americans. A recommendation currently exists to use the TG/HDL-C ratio ≥2.0 to predict insulin resistance in African Americans. The validity of this recommendation needs examination. Therefore, our aim was to determine the ability of TG/HDL-C ratio to predict insulin resistance in African Americans. In 1,903 African Americans [895 men, 1,008 women, age 55 ± 12 years, mean ± standard deviation (SD), range 35-80 years, body mass index (BMI) 31.0 ± 6.4 kg/m(2), range 18.5-55 kg/m(2)] participating in the Jackson Heart Study, a population-based study of African Americans, Jackson, Mississippi tricounty region, insulin resistance was defined by the upper quartile (≥4.43) of homeostasis model assessment of insulin resistance (HOMA-IR). An area under the receiver operating characteristic curve (AUC-ROC) of >0.70 was required for prediction of insulin resistance by TG/HDL-C. The optimal test cutoff was determined by the Youden index. HOMA-IR was similar in men and women (3.40 ± 2.03 vs. 3.80 ± 2.46, P = 0.60). Women had lower TG (94 ± 49 vs. 109 ± 65 mg/dL P < 0.001) and TG/HDL-C (1.9 ± 1.4 vs. 2.7 ± 2.1, P < 0.001). For men, AUC-ROC for prediction of insulin resistance by TG/HDL-C was: 0.77 ± 0.01, mean ± standard error (SE), with an optimal cutoff of ≥2.5. For women, the AUC-ROC was 0.66 ± 0.01, rendering an optimal cutoff indefinable. When women were divided in two groups according to age, 35-50 years and 51-80 years, the results did not change. In African-American men, the recommended TG/HDL-C threshold of 2.0 should be adjusted upward to 2.5. In African-American women, TG/HDL-C cannot identify insulin resistance. The Jackson Heart Study can help determine the efficacy of screening programs in African-Americans.