The Link between Obesity and Inflammatory Markers in the Development of Type 2 Diabetes in Men of Black African and White European Ethnicity.

Olah Hakim,A Margot Umpleby,Oluwatoyosi Bello,Louise M Goff,Janet L Peacock,Stephanie A Amiel,Meera Ladwa,Geoffrey Charles-Edwards

doi:10.3390/nu12123796

Abstract

In this study, we aimed to assess ethnic differences in visceral (VAT), deep subcutaneous (dSAT), and superficial subcutaneous (sSAT) adipose tissue and their relationships with inflammatory markers between white European (WE) and black West African (BWA) men with normal glucose tolerance (NGT) and type 2 diabetes (T2D). Forty-two WE (23 NGT/19 T2D) and 43 BWA (23 NGT/20 T2D) men underwent assessment of plasma inflammatory markers using immunoassays alongside Dixon magnetic resonance imaging to quantify L4-5 VAT, dSAT and sSAT. Despite no ethnic differences in sSAT and dSAT, BWA men exhibited lower VAT (p = 0.002) and dSAT:sSAT (p = 0.047) than WE men. Adiponectin was inversely associated with sSAT in WE (p = 0.041) but positively associated in BWA (p = 0.031) men with T2D. Interleukin-6 (IL-6) was associated with VAT in WE but not in BWA men with NGT (WE: p = 0.009, BWA: p = 0.137) and T2D (WE: p = 0.070, BWA: p = 0.175). IL-6 was associated with dSAT in only WE men with NGT (WE: p = 0.030, BWA: p = 0.833). The only significant ethnicity interaction present was for the relationship between adiponectin and sSAT (Pinteraction = 0.003). The favourable adipose tissue distribution and the weaker relationships between adiposity and inflammation in BWA men suggest that adipose tissue inflammation may play a lesser role in T2D in BWA than WE men.

Highlights

The global increase in type 2 diabetes (T2D) is concomitant with the rise in obesity; the role of adipose tissue dysfunction in driving insulin resistance is an area of increasing interest in T2D research [1,2]
We explored the impact of ethnicity on regional adipose tissue deposition as well as the relationships between measures of regional adiposity and inflammatory markers in men of white European (WE) and black West African (BWA) ethnicity in two glycaemic states, normal glucose tolerance (NGT) and T2D
The ethnic differences in visceral adipose tissue (VAT) and VAT:subcutaneous adipose tissue (SAT) that we found between the WE and BWA men supports previous findings which have consistently shown VAT is lower in black populations compared to their white counterparts with no ethnic differences in SAT [25,26]

Summary

Introduction

The global increase in type 2 diabetes (T2D) is concomitant with the rise in obesity; the role of adipose tissue dysfunction in driving insulin resistance is an area of increasing interest in T2D research [1,2]. Populations of African descent suffer greater prevalence rates of T2D compared to white populations, which is not entirely explained by obesity or socioeconomic factors [3,4]. It is Nutrients 2020, 12, 3796; doi:10.3390/nu12123796 www.mdpi.com/journal/nutrients. The deposition of abdominal fat, visceral adipose tissue (VAT), has long been related to insulin resistance and T2D while the increased ratio of subcutaneous adipose tissue (SAT) to VAT has been shown to have metabolically protective qualities [6,7,8]. The sSAT is considered to be the primary storage compartment of excess energy and the metabolically safest fat storage depot; upon an excess increase in sSAT, there is a disproportionate increase in dSAT, which is morphologically and metabolically likened to VAT [9,10]

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