Associations Between Pancreatic Lipids and β-Cell Function in Black African and White European Men With Type 2 Diabetes

CONTEXT: Intrapancreatic lipid (IPL) has been linked to β-cell dysfunction. Black populations disproportionately develop type 2 diabetes (T2D) and show distinctions in β-cell function compared with white populations. OBJECTIVE: We quantified IPL in white European (WE) and black West African (BWA) men with early T2D and investigated the relationships between IPL and β-cell insulin secretory function (ISF). DESIGN, SETTING, AND PARTICIPANTS: We performed a cross-sectional assessment of 18 WE and 19 BWA middle-age men with early T2D as part of the South London Diabetes and Ethnicity Phenotyping study. MAIN OUTCOME MEASURES: The participants underwent Dixon MRI to determine IPL in the pancreatic head, body, and tail and subcutaneous and visceral adipose tissue volumes. Modeled first- and second-phase ISFs were comprehensively determined using C-peptide measurements during a 3-hour meal tolerance test and a 2-hour hyperglycemic clamp test. RESULTS: The WE men had greater mean IPL levels compared with BWA men (P = 0.029), mainly owing to greater IPL levels in the pancreatic head (P = 0.009). The mean IPL level was inversely associated with orally stimulated first-phase ISF in WE but not BWA men (WE, r = -0.554, P = 0.026; BWA, r = -0.183, P = 0.468). No association was found with orally stimulated second-phase ISF in either WE or BWA men. No associations were found between the mean IPL level and intravenously stimulated ISF. CONCLUSIONS: The IPL levels were lower in BWA than WE men with early T2D, and the lack of inverse association with first-phase ISF in BWA men indicates that IPL might be a less important determinant of the development of T2D in BWA than in WE men.