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 with beta-cell dysfunction. Black populations suffer disproportionately from type 2 diabetes (T2D) and show distinctions in beta-cell function compared to Whites.

Objective: We aimed to quantify IPL in White European (WE) and Black West African (BWA) men with early T2D, and to investigate relationships between IPL and beta-cell insulin secretory function (ISF).

Design, Setting and Participants: We performed a cross-sectional assessment of 18 WE and 19 BWA middle-aged men with early T2D as part of the South London Diabetes and Ethnicity Phenotyping (Soul-Deep) study.

Main Outcome Measures: Participants underwent Dixon magnetic resonance imaging to determine IPL in the pancreatic head, body, and tail, and subcutaneous and visceral adipose tissue volumes. Modelled first-phase and second-phase ISF were comprehensively determined using c-peptide measurements during a 3-hour meal tolerance test and a 2-hour hyperglycemic clamp test.

Results: WE men had higher mean IPL than BWA men (P=0.029), mainly due to higher IPL in the pancreatic head in WE men (P=0.009). Mean IPL 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); there was no association with orally stimulated second-phase ISF in either WE or BWA men. No significant associations were found between mean IPL and intravenously stimulated ISF.

Conclusions: IPL is lower in BWA than WE men with early T2D, and the lack of inverse association with orally stimulated first phase ISF in BWA men indicates that IPL may be a less important determinant of the development of T2D in BWA compared to WE men.