Acanthosis nigricans, vitamin D, and insulin resistance in obese children and adolescents

Association of Blood Calcidiol Levels and Metabolic Syndrome in Children and Adolescents With Vitamin D Deficiency

This retrospective cohort study aimed to determine whether severe calcidiol deficiency [25-hydroxyvitamin (OH)D <30 nmol/L] improvement has a beneficial effect on cardiometabolic parameters in children and adolescents (5-17 years) with or without metabolic syndrome (MetS). Logistic regression analysis was performed to test for multivariate associations between potential confounders and changes in vitamin D (VD) status from baseline to follow-up care when predicting binary categorical outcomes. Of 562 participants, 146 (26%) had MetS. Individuals with severe VD deficiency (VDD) were more likely to have MetS with elevated blood pressure than those with sufficient (≥75 nmol) VD levels (adjusted odds ratio [AOR], 4.46; 1.08-18.43; p < .05) at follow-up. In the logistic regression model, every unit increase in VD across time decreased the odds of MetS (AOR, 0.98; 95% confidence interval: [0.96, 0.99]; p < .05). Improvement in VD status demonstrated a beneficial metabolic effect in children and adolescents with severe VDD.

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

Background: 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). Objectives: To test whether the clinical diagnosis of AN is a strong predictor for vitamin D deficiency (VDD) in children. Methods: 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. Results: 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. Conclusion: Children and adolescents with AN are at a higher risk of VDD and should likely be tested for low calcidiol levels.

Acanthosis Nigricans as a Clinical Predictor of Insulin Resistance in Obese Children

PURPOSE

This study aimed to evaluate the utility of acanthosis nigricans (AN) severity as an index for predicting insulin resistance in obese children.

METHODS

The subjects comprised 74 obese pediatric patients who attended the Department of Pediatrics at Chosun University Hospital between January 2013 and March 2016. Waist circumference; body mass index; blood pressure; fasting glucose and fasting insulin levels; lipid profile; aspartate transaminase, alanine transaminase, glycated hemoglobin, C-peptide, and uric acid levels; and homeostatic model assessment insulin resistance (HOMA-IR) and quantitative insulin check sensitivity index (QUICKI) scores were compared between subjects with AN and those without AN. Receiver operating characteristic curves were used to investigate the utility of the AN score in predicting insulin resistance. HOMA-IR and QUICKI were compared according to AN severity.

RESULTS

The With AN group had higher fasting insulin levels (24.1±21.0 mU/L vs. 9.8±3.6 mU/L, p<0.001) and HOMA-IR score (5.74±4.71 vs. 2.14±0.86, p<0.001) than the Without AN group. The AN score used to predict insulin resistance was 3 points or more (sensitivity 56.8%, specificity 83.9%). HOMA-IR scores increased with AN severity, from the Without AN group (mean, 2.15; 95% confidence interval [CI], 1.72-2.57) to the Mild AN (mean, 4.15; 95% CI, 3.04-5.25) and Severe AN groups (mean, 7.22; 95% CI, 5.08-9.35; p<0.001).

CONCLUSION

Insulin resistance worsens with increasing AN severity, and patients with Severe AN (AN score ≥3) are at increased risk of insulin resistance.