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

OBJECTIVES: The aim of this study is to identify factors accounting for the variation in 25-hydroxyvitamin D levels in a pediatric obese population. PATIENTS AND METHODS: One hundred and forty-nine obese children and adolescents (BMI ≥95th percentile) were evaluated in a pediatric endocrine office. Acanthosis nigricans (AN) skin lesions were rated on a 4-point scale. RESULTS: The 25-hydroxyvitamin D levels were significantly different between those without AN and those with any severity of AN (p=<0.001). Insulin levels were only significantly different between those with no and severe AN (p=0.007). A general linear model showed that month of visit predicted 19.0% of the variation and AN an additional 2.2%. When AN was dropped from the full model, log-transformed HOMA-IR remained insignificant (p=0.164). CONCLUSIONS: Season of evaluation was the main determinant of 25-hydroxyvitamin D levels. Severity of AN was a stronger predictor of 25-hydroxyvitamin D level variation than the measure of insulin resistance HOMA-IR.

Predictors of parental interest in continuous glucose monitoring for children with type 1 diabetes.

BACKGROUND: Optimal control of type 1 diabetes (T1D) in children minimizes long-term complications, but increases hypoglycemic events. A continuous glucose monitor (CGM) can provide real-time information about glucose levels and trends. Little has been published on the characteristics of patients most willing to use CGM. METHODS: Online survey software was utilized to administer a 50-item questionnaire to parents of children with T1D. The primary outcome was whether the parent expressed a high level of interest in CGM. The proportion of parents who expressed a high level of interest was compared across demographic and clinical variables via chi(2) tests (alpha = 0.05). RESULTS: Analysis was performed on 457 surveys. The mean +/- SD age of the children was 10 +/- 4.1 years. Mean reported hemoglobin A1c (HbA1c) was 7.8 +/- 1.3%. Of the respondents, 70% used continuous subcutaneous insulin infusion (CSII). Parents reported an average of eight blood glucose (BG) checks daily. Over 90% of the parents indicated a high level of interest in having their child use a CGM. Primary variables related to interest in a CGM were use of CSII (P = 0.002), checking BG more than six times daily (P = 0.005), and parental worry about high or low BG (P = 0.0012 and P = 0.02, respectively). Age of the child and HbA1c were not related to parental interest in a CGM. CONCLUSIONS: Overall parental interest in CGM was high. Use of CSII, frequent BG checks, and parental worry, but not age of the child or diabetes control, were associated with parental interest in using a CGM.

Closed-loop artificial pancreas using subcutaneous glucose sensing and insulin delivery and a model predictive control algorithm: the Virginia experience.

BACKGROUND: Recent progress in the development of clinically accurate continuous glucose monitors (CGMs), automated continuous insulin infusion pumps, and control algorithms for calculating insulin doses from CGM data have enabled the development of prototypes of subcutaneous closed-loop systems for controlling blood glucose (BG) levels in type 1 diabetes. The use of a new personalized model predictive control (MPC) algorithm to determine insulin doses to achieve and maintain BG levels between 70 and 140 mg/dl overnight and to control postprandial BG levels is presented. METHODS: Eight adults with type 1 diabetes were studied twice, once using their personal open-loop systems to control BG overnight and for 4 h following a standardized meal and once using a closed-loop system that utilizes the MPC algorithm to control BG overnight and for 4 h following a standardized meal. Average BG levels, percentage of time within BG target of 70-140 mg/dl, number of hypoglycemia episodes, and postprandial BG excursions during both study periods were compared. RESULTS: With closed-loop control, once BG levels achieved the target range (70-140 mg/dl), they remained within that range throughout the night in seven of the eight subjects. One subject developed a BG level of 65 mg/dl, which was signaled by the CGM trend analysis, and the MPC algorithm directed the discontinuance of the insulin infusion. The number of overnight hypoglycemic events was significantly reduced (p = .011) with closed-loop control. Postprandial BG excursions were similar during closed-loop and open-loop control. CONCLUSION: Model predictive closed-loop control of BG levels can be achieved overnight and following a standardized breakfast meal. This "artificial pancreas" controls BG levels as effectively as patient-directed open-loop control following a morning meal but is significantly superior to open-loop control in preventing overnight hypoglycemia.