Racial and Ethnic Differences in an Estimated Measure of Insulin Resistance Among Individuals With Type 1 Diabetes

Abstract

OBJECTIVEInsulin resistance is greater in racial/ethnic minorities than in non-Hispanic whites (NHWs) for those with and without type 2 diabetes. Because previous research on insulin resistance in type 1 diabetes was limited to NHWs, racial/ethnic variation in an estimated measure of insulin resistance in type 1 diabetes was determined.RESEARCH DESIGN AND METHODSThe sample included 79 individuals with type 1 diabetes diagnosed at age <18 years (32.9% NHWs, 46.8% non-Hispanic black [NHB], 7.6% other/mixed, and 12.7% Hispanic) and their families. Estimated glucose disposal rate (eGDR) (milligrams per kilogram per minute; a lower eGDR indicates greater insulin resistance) was calculated using A1C, waist circumference, and hypertension status.RESULTSMean current age was 13.5 years (range 3.2–32.5) and diabetes duration was 5.7 years (0.1–19.9). eGDR was inversely associated with age. Compared with that in NHWs, age-adjusted eGDR was significantly lower among nonwhites (NHB, other/mixed, and Hispanic: Δ = −1.83, P = 0.0006). Age-adjusted eGDR was negatively associated with body fat, triglycerides, urinary albumin/creatinine, acanthosis nigricans, parental obesity, and parental insulin resistance and positively related to HDL and sex hormone–binding globulin. In multivariable analysis, lower eGDR was significantly associated with older age, nonwhite race/ethnicity, acanthosis, and lower HDL.CONCLUSIONSMinorities with type 1 diabetes are significantly more insulin resistant, as measured by eGDR, than NHWs. Exploring potential mechanisms, including disparities in care and/or physiological variation, may contribute to preventing racial/ethnic differences in insulin resistance–associated outcomes.

Use of the Estimated Glucose Disposal Rate as a Measure of Insulin Resistance in an Urban Multiethnic Population With Type 1 Diabetes

“…This is consistent with a multiethnic study of 1,086 nondiabetic individuals; Haffner et al (6) showed that African Americans and Hispanics were more IR (using the frequently sampled intravenous glucose tolerance test) than non-Hispanic whites. Danielson et al (16) examined insulin sensitivity using eGDR in a pediatric multiethnic cohort with type 1 diabetes ( n = 79) and found less IR among non-Hispanic whites compared with other ethnic groups; in contrast to our study, the average age of patients in the study by Danielson et al was 13.5 years, ranging from 3.2–32.5 years, and all patients had onset of type 1 diabetes before age 18.…”

“…Furthermore, we confirmed that low eGDR is associated with an increased risk of diabetes vascular complications. Although the concept of IR among individuals with type 1 diabetes is not new (3–5), few studies have explored this phenomenon in nonwhite populations or assessed interethnic differences (6,16). To our knowledge, this is the first study of adults with type 1 diabetes that was adequately powered to analyze eGDR, demographic and metabolic confounders, and diabetes complications among three major ethnic groups.…”

“…To date, studies examining the use of eGDR as a measure of IR in type 1 diabetes have been limited to mostly nonminority cohorts (13–15). Studies that have considered interethnic differences in insulin sensitivity have used more invasive methods, were restricted to pediatric populations, and may not have been powered adequately for comparisons among ethnic groups (6,16). …”

Cardiovascular Disease Risk Factors in Youth With Diabetes Mellitus

“…38 In addition, differences in insulin resistance (IR) are another possible factor. Danielson et al 39 showed that IR was significantly lower in NHW youth than in minority youth with T1DM.…”

Diabetes and Nonalcoholic Fatty Liver Disease: A Pathogenic Duo

“…The progression of NAFLD in the setting of insulin resistance is likely to be driven by the pathogenic effects of the subsequent hyperinsulinemia and also by varying degrees of relative insulin deficiency, particularly in diabetes. Insulin resistance is almost invariable in type 2 diabetes, and it is also increasingly recognized as an ongoing issue in many patients with type 1 diabetes, especially those of increasing age (175,176). By definition, prediabetes and diabetes are states of relative insulin deficiency that, when combined with excess caloric intake and obesity, will commonly contribute to increased portal fatty acids and ectopic fat deposition, including in the liver.…”