Ethnic differences in intrahepatic lipid and its association with hepatic insulin sensitivity and insulin clearance between men of black and white ethnicity with early type 2 diabetes.

Intrahepatic lipid (IHL) is linked with reduced hepatic insulin sensitivity and insulin clearance. Despite their high risk for type 2 diabetes (T2D), there have been limited investigations of these relationships in black populations. We investigated these relationships in 18 white European (WE) and 18 black West African (BWA) men with T2D <5 years. They underwent magnetic resonance imaging to quantify IHL, a hyperinsulinemic euglycaemic clamp with [6,6 2 H2 ] glucose infusion to assess hepatic insulin sensitivity and a hyperglycaemic clamp to assess insulin clearance. BWA men had lower IHL than WE men (3.7 [5.3] vs 6.6 [10.6]%, P = 0.03). IHL was inversely associated with basal hepatic insulin sensitivity in WE but not BWA men (BWA: r = -0.01, P = 0.96; WE: r = -0.72, P = 0.006) with a significant interaction by ethnicity (Pinteraction = 0.05); however, IHL was not associated with % suppression of endogenous glucose production by insulin in either ethnicity. IHL showed a trend to an association with insulin clearance in BWA only (BWA: r = -0.42, P = 0.09; WE: r = -0.14, P = 0.58). The lack of association between IHL and hepatic insulin sensitivity in BWA men indicates IHL may play a lesser detrimental role in T2D in BWA men.

A prospective study of glycemia, body size, insulin resistance and the risk of hypertension in Mauritius.

OBJECTIVE: To estimate the associations between new-onset hypertension and glycemia, insulin resistance, and overall and regional adiposity in a prospective study conducted in Mauritius. RESEARCH DESIGN AND METHODS: Three thousand five hundred and eighty-one adults without hypertension, pregnancy, or known diabetes at baseline (1987) were followed for incident hypertension in 1992 and 1998, (systolic blood pressure > or =140 mmHg or diastolic blood pressure > or =90 mmHg or antihypertensive medication treatment). Other measurements included fasting plasma glucose and 2-h plasma glucose after a 75-g oral glucose load, fasting insulin, BMI, waist circumference, smoking, alcohol use, exercise, and demographic information. Insulin sensitivity was estimated by the computerized homeostasis model assessment (HOMA2) program. RESULTS: In multivariable logistic models that included age, gender, ethnicity, alcohol use, exercise, education, systolic blood pressure, diastolic blood pressure, homeostasis model assessment, fasting plasma glucose, 2-h plasma glucose, BMI, and waist circumference, the independent predictors of incident hypertension by time of follow-up were (odds ratio for a 1 SD increase; 95% confidence interval): 1992 - age (1.73; 1.47-2.03), Creole ethnicity (1.42; 1.04-1.94), 2-h plasma glucose (1.26; 1.04-1.51); 1998 - age (1.60; 1.40-1.83) and BMI (1.33; 1.05-1.69). Also, systolic blood pressure and diastolic blood pressure significantly predicted hypertension at both time points. CONCLUSION: Risk factor patterns depended on duration of follow-up. Over 5 years, hypertension was related to 2-h plasma glucose but not to measures of body size or homeostasis model assessment, while over 11 years, incident hypertension was related to BMI but not waist circumference, 2-h plasma glucose, or homeostasis model assessment. These findings support a more important role for 2-h plasma glucose and overall adiposity than waist circumference, fasting plasma glucose, or insulin resistance in the development of hypertension in Mauritius.