Acanthosis Nigricans Is a Strong Predictor of Low Blood Calcidiol Levels in Children and Adolescents

Clinical consensus differs as to when blood vitamin D (VD) levels should be measured in children. Obesity and metabolic syndrome are risk factors for low VD levels and are also associated with acanthosis nigricans (AN). To test whether the clinical diagnosis of AN is a strong predictor for vitamin D deficiency (VDD) in children. Within the study period (2015-2020), we identified 677 consecutive individuals (age <18 years) with available calcidiol measurements and compared those with (n = 273) and without (n = 404) AN. Bivariate associations and the occurrence of AN were tested using the chi-squared test. Multivariate logistic regression was performed to control for confounding variables, and adjusted odds ratios with 95% confidence intervals (CI) were reported. Multiple regression analysis was performed, and unstandardized beta coefficients, standard errors, and standardized beta coefficients were reported. Individuals with AN had 3.6 times higher odds of VDD than those without (95% CI: 1.38-9.51, P = 0.009). Males had 0.41 times lower odds of having AN than females (95% CI: 0.21-0.79, P = 0.008). Individuals with vitamin D sufficiency (VDS) were much less likely to be diagnosed with metabolic syndrome compared with those who were vitamin D deficient (P = 0.011), even after adjusting for body mass index z-scores. Children and adolescents with AN are at a higher risk of VDD and should likely be tested for low calcidiol levels.