Endocrine Abstracts

Background: Acanthosis nigricans (AN) is a cutaneous condition characterised by pigmented hyperkeratosis of the skin flexures and neck and occurs most commonly in association with hyperinsulinaemia and insulin resistance (IR). A high prevalence of hyperinsulinaemia and abnormal glucose intolerance has been reported in the Emirati population. Current knowledge of AN suggests that it is a strong visible cutaneous marker associated with IR and can precede the onset of hyperglycaemia. We explored associations of IR, type 1 diabetes (T1DM) and type 2 diabetes (T2DM) with AN (independent of BMI), compared to a control group without AN.

Methods: Case-control study conducted at Imperial College London Diabetes Centre (ICLDC, UAE). Individuals aged <40 years with a clinical diagnosis of AN at <18 years and controls without AN aged <40 years; with or without a diagnosis of diabetes were included. A total of 416 patients, 141 with AN, 275 without AN were recruited. IR was assessed using the Homeostatic Model Assessment of insulin resistance (HOMA2-IR) score.

Results: Mean HOMA2-IR was 0.9, 3.0, 3.6 and 4.2 in individuals with T1DM, NGT, Prediabetes and T2DM, respectively. BMI (OR=1.13, P<0.0001***) and HOMA2-IR (OR=1.16, P=0.008**) were independently and significantly associated with AN. Among individuals with T2DM, HOMA2-IR was significantly higher in association with AN features in women (P=0.03*) but not in men (P= 0.23). Sex-specific differences in associations between AN and HOMA2-B and HOMA2-S were noted. Men with AN demonstrated higher HOMA2-B (OR=1.01, P=0.0353*) than men without AN, while HOMA2-S was significanlty lower in women with AN OR=0.98, P=0.0032**) than without; HOMA2-S in men and HOMA2-B in women were not significantly associated with AN.

Conclusion: This is the first report we are aware of investigating AN and its association with IR, T1DM and T2DM in both males and females in a case-control study in an Emirati population. Awareness and early identification of AN as a clinical marker of IR enables timely recognition of underlying metabolic complications.