Acanthosis nigricans in type 2 diabetes: prevalence, correlates and potential as a simple clinical screening tool - a cross-sectional study in the Caribbean

BACKGROUND: This study aimed to evaluate the role of acanthosis nigricans (AN) as a marker of Type 2 Diabetes Mellitus (T2DM) by studying its prevalence and relationship with age, ethnicity, anthropometry and other risk factors for T2DM in the Trinidadian population. METHODS: 311 successive adult patients with T2DM were recruited at diabetic clinics and inpatient wards across Trinidad. The presence, severity and texture of AN at the neck were assessed. Demographic, clinical and anthropometric characteristics were also measured, and logistic regression was used to model their relationship with presence of AN. RESULTS: The mean (SD) age was 58.1 years (12.6). 55.6% were female. 61.1% were East Indian, 24.4% African and 14.5% mixed ethnicity. The mean (SD) BMI was 27.3 kg/m(2) (6.0) and the mean (SD) waist circumference was 96.7 cm (14.2). Prevalence of AN was 52.7% (95% CI 47.2, 58.3). There was a greater odds of AN among diabetic patients who were: younger (p < 0.001); female (OR 1.67; 95% CI 1.06, 2.62); or East Indian rather than African (0.45; 0.26, 0.77) or mixed (0.43; 0.22, 0.84) descendents. There was a greater age-, sex- and ethnicity-adjusted odds of AN among those: overweight (3.98; 2.10, 7.55) or obese (8.31; 3.84, 18.00) versus normal BMI; centrally obese (4.72; 2.65, 8.43); with history of hypertension (2.19; 1.27, 3.79) or history of hypercholesterolemia (1.72; 1.02, 2.90), but there was no evidence of this demographic-adjusted association (p > 0.4) between AN and history of previous MI or CVA, family history of T2DM, T2DM treatment regimen, duration of T2DM or random blood glucose. On further multivariable analysis, only age, sex, ethnicity, BMI and waist circumference were independently associated with AN (p < 0.05) and the effect of BMI varied with ethnicity. CONCLUSIONS: There was a high prevalence of AN both overall and across age, sex and ethnic groups of diabetic patients. AN exhibited much potential as a valuable addition to T2DM risk assessment in the Trinidadian and similar settings.