Abstract
Background: People of Black African ethnicity are at high risk of Type 2 Diabetes (T2D) as lifestyle changes, as already seen in diaspora environments, are associated with a more aggressive disease onset.Aims: We investigated the impact of ethnicity on progression of T2D and metabolic
regulation.
Methods: 1790 adults with new-onset T2D were recruited and followed for 2 years in South London Diabetes study (SOUL-D). Black West African (BWA), African-Caribbean (AC) and White European (WE) ethnic groups were compared. Insulin secretion was measured in 20 BWA and 20 WE men with T2D duration <5 years, matched for age and BMI, using hyperglycaemic clamps (HC) and mixed meal tolerance tests (MMTT).
Results: BWA and AC were younger (p<0.001); had lower waist circumference (p<0.001) and higher HbA1c at diagnosis (p=0.001). At year 2, HbA1c was not different, but BWA and AC were on more diabetes medications (p=0.01). On phenotyping, BWA men had lesser c-peptide responses to IV and oral challenge in the second phase only (HC c-peptide (p=0.78), 2nd phase (p=0.001) and MMTT (p=0.002).2nd phase insulin response to HC (p=0.01) was significantly lower in BWA men but not in MMTT(p=0.44).
Conclusions: BWA ethnicity is associated with younger onset and lesser central obesity at diagnosis of T2D and greater requirement for medication to achieve comparable glycaemic control than WE ethnicity. Exaggerated insulin secretory deficits in early T2D in BWA compared to WE men are compatible with earlier beta cell exhaustion, slightly compensated by possible reduced hepatic insulin clearance to oral glucose challenge. Treatment to preserve insulin secretory capacity may have particular benefit in preventing progression to T2D in BWA populations.
| Date of Award | 1 Mar 2023 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Louise Goff (Supervisor) & Stephanie Amiel (Supervisor) |