Frequency of abnormal carbohydrate metabolism and diabetes in a population-based screening of adolescents

Estimating incidence of type 1 and type 2 diabetes using prevalence data: the SEARCH for Diabetes in Youth study

BACKGROUND

Incidence is one of the most important epidemiologic indices in surveillance. However, determining incidence is complex and requires time-consuming cohort studies or registries with date of diagnosis. Estimating incidence from prevalence using mathematical relationships may facilitate surveillance efforts. The aim of this study was to examine whether a partial differential equation (PDE) can be used to estimate diabetes incidence from prevalence in youth.

METHODS

We used age-, sex-, and race/ethnicity-specific estimates of prevalence in 2001 and 2009 as reported in the SEARCH for Diabetes in Youth study. Using these data, a PDE was applied to estimate the average incidence rates of type 1 and type 2 diabetes for the period between 2001 and 2009. Estimates were compared to annual incidence rates observed in SEARCH. Precision of the estimates was evaluated using 95% bootstrap confidence intervals.

RESULTS

Despite the long period between prevalence measures, the estimated average incidence rates mirror the average of the observed annual incidence rates. Absolute values of the age-standardized sex- and type-specific mean relative errors are below 8%.

CONCLUSIONS

Incidence of diabetes can be accurately estimated from prevalence. Since only cross-sectional prevalence data is required, employing this methodology in future studies may result in considerable cost savings.

Building a Population Representative Pediatric Biobank: Lessons Learned From the Greater Cincinnati Childhood Cohort

Background: Biobanks can accelerate research by providing researchers with samples and data. However, hospital-based recruitment as a source for controls may create bias as who comes to the hospital may be different from the broader population. Methods: In an effort to broadly improve the quality of research studies and reduce costs and challenges associated with recruitment and sample collection, a group of diverse researchers at Cincinnati Children's Hospital Medical Center led an institution-supported initiative to create a population representative pediatric "Greater Cincinnati Childhood Cohort (GCC)." Participants completed a detailed survey, underwent a brief physician-led physical exam, and provided blood, urine, and hair samples. DNA underwent high-throughput genotyping. Results: In total, 1,020 children ages 3-18 years living in the 7 county Greater Cincinnati Metropolitan region were recruited. Racial composition of the cohort was 84% non-Hispanic white, 15% non-Hispanic black, and 2% other race or Hispanic. Participants exhibited marked demographic and disease burden differences by race. Overall, the cohort was broadly used resulting in publications, grants and patents; yet, it did not meet the needs of all potential researchers. Conclusions: Learning from both the strengths and weaknesses, we propose leveraging a community-based participatory research framework for future broad use biobanking efforts.

Young-onset type 2 diabetes mellitus - implications for morbidity and mortality

Accumulating data suggest that type 2 diabetes mellitus (T2DM) in younger people (aged <40 years), referred to as young-onset T2DM, has a more rapid deterioration of β-cell function than is seen in later-onset T2DM. Furthermore, individuals with young-onset T2DM seem to have a higher risk of complications than those with type 1 diabetes mellitus. As the number of younger adults with T2DM increases, young-onset T2DM is predicted to become a more frequent feature of the broader diabetes mellitus population in both developing and developed nations, particularly in certain ethnicities. However, the magnitude of excess risk of premature death and incident complications remains incompletely understood; likewise, the potential reasons for this excess risk are unclear. Here, we review the evidence pertaining to young-onset T2DM and its current and future burden of disease in terms of incidence and prevalence in both developed and developing nations. In addition, we highlight the associations of young-onset T2DM with premature mortality and morbidity.

Youth sports participation and health status in early adulthood: A 12-year follow-up

Examining association between serial participation in youth organized sports (OS) and concurrent cardiometabolic risk factors, with long-term health status, will aid understanding the role of OS participation. Combining data from a prospective study and a follow-up survey, we aimed to determine association between youth OS participation and cardiometabolic risk factors with health and physical activity (PA) in young adulthood. Cardiometabolic risk factors were monitored yearly, and OS involvement through middle school, high school, and college, together with current status was recorded 12 years after the initial study began; 462 participants completed follow-up. Cardiometabolic risk factors included: body mass index (BMI), waist circumference, blood pressure, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) cholesterol and triglycerides, fasting glucose and insulin. Participants continuing OS participation from middle to high school and/or college had significantly lower BMI/BMI z-scores [24.7 vs 27.4 (p < 0.05) and 0.51 vs 0.82 (p < 0.05), respectively] and significantly higher HDL [48.7 vs 45.4 (p ≤ 0.05)] than those without OS participation after middle school. Waist circumference of females was significantly smaller in those who participated in OS from middle to high school and/or college (84.9 cm) compared to those who had no OS (92.1 cm), (p < 0.05). Participants continuing OS from middle to high school and/or college reported significantly higher follow-up PA levels than those who had no OS after middle school (p < 0.001). This study provides novel data showing serial participation in OS from middle to high school and/or college was associated with a superior cardiometabolic health profile in school and increased PA levels at 12-year follow-up.

Anthropometric and biochemical correlates of PAPP-A2, free IGF-I, and IGFBP-3 in childhood

OBJECTIVE

Pregnancy-associated plasma protein-A2 (PAPP-A2) is a metalloproteinase that cleaves IGFBP-3 and IGFBP-5. Human mutations in PAPPA2 result in short stature with a low percentage of free IGF-I. Little is known about PAPP-A2 levels and the regulation of free IGF-I throughout childhood. We examined PAPP-A2 and intact IGFBP-3 levels in childhood and explored associations between PAPP-A2, free and total IGF-I, and total and intact IGFBP-3 and their relationship to the percentage of free to total IGF-I and anthropometric factors.

DESIGN

Cross-sectional study at a single center.

METHODS

PAPP-A2, free IGF-I, and intact IGFBP-3 levels were measured in childhood (3-18 years old) and an evaluation of the relationship between these proteins and anthropometric factors.

RESULTS

In 838 children, PAPP-A2 consistently decreased throughout childhood. In contrast, free IGF-I increased. A pubertal peak in free IGF-I was present in females but was less evident in males. Intact and total IGFBP-3 increased throughout childhood; however, intact IGFBP-3 had a more marked rise than total IGFBP-3. Percent free IGF-I decreased with no distinct pubertal peak. PAPP-A2 levels positively correlated with the percent free IGF-I (Male, Female; r = 0.18, 0.38; P < 0.001) and negatively with intact IGFBP-3 (Male, Female; r = -0.58, -0.65; P < 0.0001).

CONCLUSIONS

This is the first study to describe serum PAPP-A2 and intact IGFBP-3 in children between 3 and 18 years of age. Our correlative findings suggest that PAPP-A2 is an important regulator of the percent free IGF-I which can be a marker of perturbations in the GH/IGF-I axis.

Metabolic outcomes of surgery in youth with type 2 diabetes

Youth-onset type 2 diabetes (T2D) is a formidable threat to the health of obese adolescents because of its potential for early-onset and aggressive co-morbidities and complications. The physiology of youth-onset T2D differs from T2D in adults and is associated with a greater degree of insulin resistance, a more rapid decline in pancreatic β-cell function, and a poorer response to medications. Medical management in youth is focused on combining lifestyle intervention and pharmacological treatment, but these therapies have yet to demonstrate improvements in disease progression. Metabolic bariatric surgery (MBS) is now recommended for the treatment of T2D in adults largely because of the beneficial effects on weight, ability to improve glycemic control, and, in a large proportion of people, induce diabetes remission. MBS is now being performed in adolescents with severe obesity and T2D, with initial results also showing high rates of T2D remission. Here, we review the state of medical management of youth-onset T2D and the outcomes of MBS studies in youth with T2D published to date.

Estimating prevalence of type I and type II diabetes using incidence rates: the SEARCH for diabetes in youth study

PURPOSE

Most surveillance efforts in childhood diabetes have focused on incidence, whereas prevalence is rarely reported. This study aimed to assess whether a mathematical illness-death model accurately estimated future prevalence from baseline prevalence and incidence rates in children.

METHODS

SEARCH for Diabetes in Youth is an ongoing population-based surveillance study of prevalence and incidence of diabetes and its complications among youth in the United States. We used age-, sex-, and race/ethnicity-specific SEARCH estimates of the prevalence of type I and type II diabetes in 2001 and incidence from 2002 to 2008. These data were used in a partial differential equation to estimate prevalence in 2009 with 95% bootstrap confidence intervals. Model-based prevalence was compared with the observed prevalence in 2009.

RESULTS

Most confidence intervals for the difference between estimated and observed prevalence included zero, indicating no evidence for a difference between the two methods. The width of confidence intervals indicated high precision for the estimated prevalence when considering all races/ethnicities. In strata with few cases, precision was reduced.

CONCLUSIONS

Future prevalence of type I and type II diabetes in youth may be accurately estimated from baseline prevalence and incidence. Diabetes surveillance could benefit from potential cost savings of this method.

Free Fatty Acids as an Indicator of the Nonfasted State in Children

BACKGROUND

Ensuring children are fasting for blood draws is necessary to diagnose abnormalities in glucose homeostasis. We sought to determine if serum free fatty acid (FFA) concentrations might be a useful marker to differentiate the fed and fasted states among children.

METHODS

A total of 442 inpatient (fasting) and 323 (postglucose load) oral glucose tolerance test samples of glucose, insulin, and FFA from children (age 5-18 years) who had healthy weight, overweight, or obesity were examined by receiver operating characteristic (ROC) curve analysis to identify a cut point for nonfasting. In a cross-sectional study, we compared mean FFA and percentage of FFA values below this cut point as a function of inpatient (n = 442) versus outpatient (n = 442) setting.

RESULTS

The area under the curve of FFA was significantly better (P values < .001) than the area under the curve of glucose or insulin for identifying nonfasting. FFA <287 mEq/mL had 99.0% sensitivity and 98.0% specificity for nonfasting. Mean FFA was lower in outpatients than inpatients (P < .001); only 1.6% inpatient but 9.7% outpatient FFA values were consistent with nonfasting (P < .001).

CONCLUSIONS

Clinicians cannot assume that pediatric patients are adequately fasted on arrival for fasting blood work. On the basis of having significantly lower outpatient than inpatient FFA values and more frequently suppressed FFA, children appeared less likely to be fasting at outpatient appointments. FFA value <287 mEq/mL was a sensitive and specific cutoff for nonfasting in children that may prove clinically useful.

Prevalence of abnormal glucose metabolism in pediatric acute, acute recurrent and chronic pancreatitis

Type 3C Diabetes, or diseases of the exocrine pancreas has been reported to occur in approximately 30% of adult patient with pancreatitis. The incidence of glucose abnormalities or risk factors that may predict the development of abnormal glucose in the pediatric pancreatitis population is not known. We performed a retrospective chart review from 1998–2016 for patients who carry the diagnosis of acute pancreatitis (AP), acute recurrent pancreatitis (ARP), and chronic pancreatitis (CP). We extracted glucose values, HbA1c%, and data from oral glucose tolerance and mixed meal testing with timing in relation to pancreatic exacerbations. Patient characteristic data such as age, gender, body proportions, family history of pancreatitis, exocrine function and genetic mutations were also assessed. Abnormal glucose was based on definitions put forth by the American Diabetes Society for pre-diabetes and diabetes. Fifty-two patients had AP and met criteria. Of those, 15 (29%) had glucose testing on or after the first attack, 21 (40%) were tested on or after the second attack (in ARP patients) and 16 (31%) were tested after a diagnosis of CP. Of the patients tested for glucose abnormalities, 25% (13/52) had abnormal glucose testing (testing indicating pre-DM or DM as defined by ADA guidelines. A significantly higher proportion of the abnormal glucose testing was seen in patients (85%, 11/13) with a BMI at or greater than the 85^th percentile compared to the normal glucose patients (28%, 11/39) (p = 0.0007). A significantly higher proportion of the abnormal glucose patients (77%, 10/13) had SAP during the prior AP episode to testing compared to the 10% (4/39) of the normal glucose patients (p<0.0001). Older age at DM testing was associated with a higher prevalence of abnormal glucose testing (p = 0.04). In our patient population, a higher proportion of glucose abnormalities were after the second episode of pancreatitis, however 62% (8/13) with abnormalities was their first time tested. We identified obesity and having severe acute pancreatitis (SAP) during the prior AP episode to testing could be associated with abnormal glucose. We propose that systematic screening for abnormal glucose after the first episode of acute pancreatitis in order to better establish the timing of diabetes progression.

Impact of Obesity on Pediatric Acute Recurrent and Chronic Pancreatitis

OBJECTIVE

The aim of this study was to assess the impact of obesity on pediatric acute recurrent pancreatitis or chronic pancreatitis (CP).

METHODS

We determined body mass index (BMI) status at enrollment in INSPPIRE (INternational Study group of Pediatric Pancreatitis: In search for a cuRE) cohort using CDC criteria for pediatric-specific BMI percentiles. We used the Cochran-Armitage test to assess trends and the Jonckheere-Terpstra test to determine associations.

RESULTS

Of 446 subjects (acute recurrent pancreatitis, n = 241; CP, n = 205), 22 were underweight, 258 normal weight, 75 overweight, and 91 were obese. The BMI groups were similar in sex, race, and age at presentation. Hypertriglyceridemia was more common in overweight or obese. Obese children were less likely to have CP and more likely to have acute inflammation on imaging. Compared with children with normal weight, obese or overweight children were older at first acute pancreatitis episode and diagnosed with CP at an older age. Obese or overweight children were less likely to undergo medical or endoscopic treatment, develop exocrine pancreatic insufficiency, and require total pancreatectomy with islet autotransplantation. Diabetes was similar among all groups.

CONCLUSIONS

Obesity or overweight seems to delay the initial acute pancreatitis episode and diagnosis of CP compared with normal weight or underweight. The impact of obesity on pediatric CP progression and severity deserves further study.

Longitudinal follow up of dysglycemia in overweight and obese pediatric patients

OBJECTIVE

To examine factors related to progression of dysglycemia in overweight and obese youth in a large primary care setting.

RESEARCH DESIGN AND METHODS

10- to 18-year-old youth with body mass index (BMI) > 85 percentile and first-time A1c 5.7%-7.9% (39-63 mmol/mol) were identified retrospectively through electronic medical records (EMR). Levels of dysglycemia were defined as low-range prediabetes (LRPD; A1c 5.7%-5.9% [39-41 mmol/mol]), high-range prediabetes (HRPD; A1c 6.0%-6.4% [42-46 mmol/mol]), or diabetes-range (A1c 6.5%-7.9% [48 mmol/mol]). Follow-up A1c and BMI were extracted from the EMR. Follow up was truncated at the time of initiation of diabetes medication.

RESULTS

Of 11 000 youth, 547 were identified with baseline dysglycemia (mean age 14.5 ± 2.2 years, 70% Hispanic, 23% non-Hispanic Black, 7% other). Of these, 206 had LRPD, 282 HRPD, and 59 diabetes. Follow-up A1c was available in 420 (77%), with median follow up of 12-22 months depending on A1c category. At follow-up testing, the percent with diabetes-range A1c was 4% in youth with baseline LRPD, 8% in youth with baseline HRPD, and 33% in youth with baseline diabetes-range A1c. There was a linear association between BMI increase and worsening A1c for LRPD (P < .001) and HRPD (P = .003).

CONCLUSIONS

Most adolescents with an initial prediabetes or diabetes-range A1c did not have a diabetes-range A1c on follow up. Moreover, prediabetes-range A1c values do not all convey equal risk for the development of diabetes, with lower rates of progression for youth with initial A1c <6%. In youth with prediabetes-range A1c, BMI stabilization was associated with improvement of glycemia.

Obesity is associated with an altered HDL subspecies profile among adolescents with metabolic disease

We aimed to determine the risk factors associated with the depletion of large HDL particles and enrichment of small HDL particles observed in adolescents with T2D. Four groups of adolescents were recruited: 1) lean insulin-sensitive (L-IS), normal BMI and no insulin resistance; 2) lean insulin-resistant (L-IR), normal BMI but insulin resistance (fasting insulin levels ≥ 25 mU/ml and homeostatic model assessment of insulin resistance ≥ 6); 3) obese insulin-sensitive (O-IS), BMI ≥ 95th percentile and no insulin resistance; and 4) obese insulin-resistant (O-IR), BMI ≥ 95th percentile and insulin resistance. Plasma was separated by using gel-filtration chromatography to assess the HDL subspecies profile and compared with that of obese adolescents with T2D (O-T2D). Large HDL subspecies were significantly lower across groups from L-IS > L-IR > O-IS > O-IR > O-T2D (P < 0.0001); small HDL particles were higher from L-IS to O-T2D (P < 0.0001); and medium-sized particles did not differ across groups. The contributions of obesity, insulin resistance, and diabetes to HDL subspecies profile were between 23% and 28%, 1% and 10%, and 4% and 9%, respectively. Obesity is the major risk factor associated with the altered HDL subspecies profile previously reported in adolescents with T2D, with smaller contributions from insulin resistance and diabetes.

Association of Type 1 Diabetes vs Type 2 Diabetes Diagnosed During Childhood and Adolescence With Complications During Teenage Years and Young Adulthood

Importance

The burden and determinants of complications and comorbidities in contemporary youth-onset diabetes are unknown.

Objective

To determine the prevalence of and risk factors for complications related to type 1 diabetes vs type 2 diabetes among teenagers and young adults who had been diagnosed with diabetes during childhood and adolescence.

Design, Setting, and Participants

Observational study from 2002 to 2015 in 5 US locations, including 2018 participants with type 1 and type 2 diabetes diagnosed at younger than 20 years, with single outcome measures between 2011 and 2015.

Exposures

Type 1 and type 2 diabetes and established risk factors (hemoglobin A1c level, body mass index, waist-height ratio, and mean arterial blood pressure).

Main Outcomes and Measures

Diabetic kidney disease, retinopathy, peripheral neuropathy, cardiovascular autonomic neuropathy, arterial stiffness, and hypertension.

Results

Of 2018 participants, 1746 had type 1 diabetes (mean age, 17.9 years [SD, 4.1]; 1327 non-Hispanic white [76.0%]; 867 female patients [49.7%]), and 272 had type 2 (mean age, 22.1 years [SD, 3.5]; 72 non-Hispanic white [26.5%]; 181 female patients [66.5%]). Mean diabetes duration was 7.9 years (both groups). Patients with type 2 diabetes vs those with type 1 had higher age-adjusted prevalence of diabetic kidney disease (19.9% vs 5.8%; absolute difference [AD], 14.0%; 95% CI, 9.1%-19.9%; P < .001), retinopathy (9.1% vs 5.6%; AD, 3.5%; 95% CI, 0.4%-7.7%; P = .02), peripheral neuropathy (17.7% vs 8.5%; AD, 9.2%; 95% CI, 4.8%-14.4%; P < .001), arterial stiffness (47.4% vs 11.6%; AD, 35.9%; 95% CI, 29%-42.9%; P < .001), and hypertension (21.6% vs 10.1%; AD, 11.5%; 95% CI, 6.8%-16.9%; P < .001), but not cardiovascular autonomic neuropathy (15.7% vs 14.4%; AD, 1.2%; 95% CI, -3.1% to 6.5; P = .62). After adjustment for established risk factors measured over time, participants with type 2 diabetes vs those with type 1 had significantly higher odds of diabetic kidney disease (odds ratio [OR], 2.58; 95% CI, 1.39-4.81; P=.003), retinopathy (OR, 2.24; 95% CI, 1.11-4.50; P = .02), and peripheral neuropathy (OR, 2.52; 95% CI, 1.43-4.43; P = .001), but no significant difference in the odds of arterial stiffness (OR, 1.07; 95% CI, 0.63-1.84; P = .80) and hypertension (OR, 0.85; 95% CI, 0.50-1.45; P = .55).

Conclusions and Relevance

Among teenagers and young adults who had been diagnosed with diabetes during childhood or adolescence, the prevalence of complications and comorbidities was higher among those with type 2 diabetes compared with type 1, but frequent in both groups. These findings support early monitoring of youth with diabetes for development of complications.

Insulin Sensitivity and β-Cell Function Improve after Gastric Bypass in Severely Obese Adolescents

OBJECTIVE

To test the hypothesis that insulin secretion and insulin sensitivity would be improved in adolescents after Roux-en-Y gastric bypass (RYGB).

STUDY DESIGN

A longitudinal study of 22 adolescents and young adults without diabetes undergoing laparoscopic RYGB (mean age 17.1 ± 1.42 years; range 14.5-20.1; male/female 8/14; Non-Hispanic White/African American 17/5) was conducted. Intravenous glucose tolerance tests were done to obtain insulin sensitivity (insulin sensitivity index), insulin secretion (acute insulin response to glucose ), and the disposition index as primary outcome variables. These variables were compared over the 1 year of observation using linear mixed modeling.

RESULTS

In the 1-year following surgery, body mass index fell by 38% from a mean of 61 ± 12.3 to 39 ± 8.0 kg/m(2) (P < .01). Over the year following surgery, fasting glucose and insulin values declined by 54% and 63%, respectively. Insulin sensitivity index increased 300% (P < .01), acute insulin response to glucose decreased 56% (P < .01), leading to a nearly 2-fold increase in the disposition index (P < .01). Consistent with improved β-cell function, the proinsulin to C-peptide ratio decreased by 21% (P < .01).

CONCLUSIONS

RYGB reduced body mass index and improved both insulin sensitivity and β-cell function in severely obese teens and young adults. These findings demonstrate that RYGB is associated with marked metabolic improvements in obese young people even as significant obesity persists.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00360373.

An 8-Year Prospective Study of Depressive Symptoms and Change in Insulin From Adolescence to Young Adulthood

OBJECTIVE

To evaluate whether depressive symptoms predict change in fasting insulin among adolescents followed into young adulthood. We hypothesized that higher depressive symptoms would predict increased insulin and that puberty and race/ethnicity would moderate this relationship.

METHODS

Data came from the Princeton School District Study, a school-based longitudinal cohort of non-Hispanic black and white adolescents (2001-2011). Depressive symptoms, fasting insulin, and body mass index were measured at baseline (adolescence) and 8 years later (young adulthood) in 685 participants. Puberty was assessed using a validated protocol measuring sex steroids and physical changes. The primary outcome was change in fasting insulin. Analyses accounted for age, sex, race, parental education, baseline insulin, body mass index z score, puberty, and time to follow-up.

RESULTS

At baseline, depressive symptoms were correlated with insulin (ρ = 0.13, p = .001). High baseline insulin predicted insulin change (B = -11.50, standard error [SE] = 2.30, p < .001). Depressive symptoms also predicted insulin change, but only for pubertal adolescents (B = -0.23, SE = 0.11, p = .038). This relationship was moderated by race (p = .047); depressive symptoms predicted insulin change only among pubertal black adolescents (p = .030), not white (p = .49), and in the direction opposite that hypothesized (Bblacks = -0.51, SE = 0.23). Post hoc analyses revealed that pubertal black adolescents with high depressive symptoms had the highest baseline insulin, which stayed high across the follow-up period.

CONCLUSIONS

Among pubertal black adolescents, elevated depressive symptoms are associated with increased risk for sustained hyperinsulinemia from adolescence into adulthood. These youths may be particularly vulnerable for Type 2 diabetes.

Rapid deterioration of insulin secretion in obese adolescents preceding the onset of type 2 diabetes

OBJECTIVE

To identify pathophysiologic changes that lead to the onset of type 2 diabetes (T2DM) in adolescents.

STUDY DESIGN

Obese adolescents with normal glucose tolerance (n = 41) were studied longitudinally over the course of 4 years with serial measure of the acute insulin response to glucose (AIRg) as well as proinsulin (PI) concentrations. Insulin resistance was estimated with the homeostatic model assessment of insulin resistance (HOMA-IR), the disposition index (DI) computed as AIRg × 1/HOMA-IR, and intravenous glucose tolerance estimated as the glucose disappearance constant.

RESULTS

Four adolescents developed diabetes mellitus (DM) during the study, and the rest of the cohort remained nondiabetic. Baseline PI exceeded the IQR of the nondiabetic group in 3 of 4 subjects with DM, and all had >85% reduction from baseline AIRg, and DI, within 6 months of diagnosis. All the subjects with DM gained weight over the course of the study, but these changes paralleled those for the nondiabetic group. HOMA-IR increased substantially in 1 of the subjects with DM at the time of diagnosis but was comparable with baseline in the other 3. The DI and glucose disappearance constant of the subjects with DM was less than the 10th percentile of the nondiabetic group before and after diagnosis.

CONCLUSION

Conversion from normal glucose tolerance to T2DM in adolescents can occur rapidly, and the onset of T2DM is heralded by a substantial decrease in AIRg and DI, as well as increased release of PI. These results support loss of β-cell function as the proximate step in the development of T2DM in this age group.

The role of perceived discrimination during childhood and adolescence in understanding racial and socioeconomic influences on depression in young adulthood

OBJECTIVE

To describe levels of perceived lifetime discrimination among young adults and determine its role in understanding this racial/ethnic disparity.

STUDY DESIGN

Data were from the Princeton School District study, a 10-year cohort study in which investigators followed 545 non-Hispanic black (46%) and white initial 5-12 graders. Perceived lifetime racial discrimination was assessed with the General Ethnic Discrimination Scale and depressive symptoms with the Center for Epidemiological Studies Depression Scale. Stepped linear and logistic regression analyses assessed the relationships of race/ethnicity, parental education, and quintiles of discrimination to depressive symptoms. Stratification by race/ethnicity explored differences in the role of discrimination in explaining the relationship between parental education and depressive symptoms.

RESULTS

Black students from professionally educated families had the greatest discrimination scores, 1.8 times greater than among their white peers (meanblack = 42.1 vs meanwhite = 22.8; P < .0001). Greater parental education was associated with lower depressive symptoms in all regression models. Race/ethnicity became predictive of depressive symptoms only after adjusting for discrimination, which was strongly associated with depressive symptoms. Stratified analysis suggested discrimination accounted for the relationship of parental education to depressive symptoms among whites. Among black subjects, accounting for discrimination unmasked a buffering effect of parental education.

CONCLUSIONS

Greater levels of parent education are protective against depression for white youth. However, for black youth, greater parent education confers both risk and protective effects. The high discrimination among black youth from families with college or professionally educated parents overwhelms the protective effect of greater levels of parent education.

Association of INSIG2 polymorphism with overweight and LDL in children

Background

Dyslipidemia and overweight are common issues in children. Identifying genetic markers of risk could lead to targeted interventions. A polymorphism of SNP rs7566605 near insulin-induced gene 2 (INSIG2) has been identified as a strong candidate gene for obesity, through its feedback control of lipid synthesis.

Objective

To identify polymorphisms in INSIG2 which are associated with overweight (BMI ≥ 85% for age) and dyslipidemia in children. Hypothesis: The C allele of rs7566605 would be significantly associated with BMI and LDL.

Design/Methods

We genotyped 15 SNPs in/near INSIG2 in 1,058 healthy children (53% non-Hispanic white (NHW), 37% overweight) participating in a school based study. Genotype was compared with BMI and lipid markers, adjusting for age, gender, and puberty.

Results

We found a significant association between the SNP rs12464355 and LDL in NHW children, p < 0.001. The G allele is protective (lower LDL). A different SNP was associated with overweight in NHW: rs17047757. SNP rs7566605 was not associated with overweight or lipid levels.

Conclusions

We identified novel genetic associations between INSIG2 and both overweight and LDL in NHW children. Polymorphisms in INSIG2 may be important in the development of obesity through its effects on lipid regulation.

Hemoglobin A1c assay variations and implications for diabetes screening in obese youth

BACKGROUND

Standardization of the hemoglobin A1c (A1c) assay has led to its increasing utilization as a screening tool for the diagnosis of prediabetes and type 2 diabetes in youth. However, significant A1c assay variability remains and has implications for clinical management.

OBJECTIVE

To describe our center's experiences with A1c results in youth and to evaluate inter-method differences and their clinical implications.

SUBJECTS

Seventy-five youth (aged 10-18 yr old), body mass index (BMI) ≥85th‰ participated.

METHODS

Seventy-two participants had two A1c values performed on the same sample, one via immunoassay (DCA Vantage Analyzer, A1c1 ) and the other via high performance liquid chromatography (Bio-Rad Variant II, A1c2 ). Nineteen had A1c run on two immunoassay devices (A1c1 and Dimensions Vista, A1c3 ).

RESULTS

Mean age of participants was 13.9 years, BMI% 97.89%, 33% male, 16% white, 21% black, and 61% Hispanic (H). Mean A1c1 was 5.68% ± 0.38 vs. a mean A1c2 of 5.73% ± 0.39, p = 0.049. Concordance in diabetes status between methods was achieved in 79% of subjects. Nineteen subjects with A1c3 results had testing performed an average of 22 ± 9 days prior to A1c1 . Mean A1c3 was 6.24% ± 0.4, compared to a mean A1c1 of 5.74% ± 0.31, (p < 0.0001). A1c1 was on average systematically -0.5 ± 0.28 lower compared to A1c3 . There was poor agreement in diabetes classification between A1c1 and A1c3 , with a concordance in classification between methods of only 36.8%.

CONCLUSIONS

Clinically significant inter-method A1c variability exists that impacts patient classification and treatment recommendations. In the screening of obese youth for diabetes, A1c results should be interpreted with caution.

Medical and non-medical complications among children and adolescents with excessive body weight

BACKGROUND

The burden of disease from childhood obesity is considerable worldwide, as it is associated with several co-morbidities, such as dyslipidemia, hypertension, type 2 diabetes (T2DM), orthopedic and psychosocial problems. We aimed at determining the prevalence of these complications in a population of children and adolescents with body weight excess.

METHODS

This is a cohort study including 774 new patients (1.7 - 17.9 yrs, mean 11.1 ± 3.0) attending a pediatric obesity care center. We assessed personal and family medical histories, physical examination, systemic blood pressure, biochemical screening tests.

RESULTS

We found that the great majority of the children suffered from at least one medical complication. Orthopedic pathologies were the most frequent (54%), followed by metabolic (42%) and cardiovascular disturbances (31%). However, non-medical conditions related to well-being, such as bullying, psychological complaints, shortness of breath or abnormal sleeping patterns, were present in the vast majority of the children (79.4%). Family history of dyslipidemia tends to correlate with the child's lipids disturbance (p = .053), and ischemic events or T2DM were correlated with cardiovascular risk factors present in the child (p = .046; p = .038, respectively).

CONCLUSIONS

The vast majority of obese children suffer from medical and non-medical co-morbidities which must be actively screened. A positive family history for cardiovascular diseases or T2DM should be warning signs to perform further complementary tests. Furthermore, well-being related-complaints should not be underestimated as they were extremely frequent.

Challenges in modelling the random structure correctly in growth mixture models and the impact this has on model mixtures

Lifecourse trajectories of clinical or anthropological attributes are useful for identifying how our early-life experiences influence later-life morbidity and mortality. Researchers often use growth mixture models (GMMs) to estimate such phenomena. It is common to place constrains on the random part of the GMM to improve parsimony or to aid convergence, but this can lead to an autoregressive structure that distorts the nature of the mixtures and subsequent model interpretation. This is especially true if changes in the outcome within individuals are gradual compared with the magnitude of differences between individuals. This is not widely appreciated, nor is its impact well understood. Using repeat measures of body mass index (BMI) for 1528 US adolescents, we estimated GMMs that required variance-covariance constraints to attain convergence. We contrasted constrained models with and without an autocorrelation structure to assess the impact this had on the ideal number of latent classes, their size and composition. We also contrasted model options using simulations. When the GMM variance-covariance structure was constrained, a within-class autocorrelation structure emerged. When not modelled explicitly, this led to poorer model fit and models that differed substantially in the ideal number of latent classes, as well as class size and composition. Failure to carefully consider the random structure of data within a GMM framework may lead to erroneous model inferences, especially for outcomes with greater within-person than between-person homogeneity, such as BMI. It is crucial to reflect on the underlying data generation processes when building such models.

Prevalence of type 1 and type 2 diabetes among children and adolescents from 2001 to 2009

IMPORTANCE

Despite concern about an "epidemic," there are limited data on trends in prevalence of either type 1 or type 2 diabetes across US race and ethnic groups.

OBJECTIVE

To estimate changes in the prevalence of type 1 and type 2 diabetes in US youth, by sex, age, and race/ethnicity between 2001 and 2009.

DESIGN, SETTING, AND PARTICIPANTS

Case patients were ascertained in 4 geographic areas and 1 managed health care plan. The study population was determined by the 2001 and 2009 bridged-race intercensal population estimates for geographic sites and membership counts for the health plan.

MAIN OUTCOMES AND MEASURES

Prevalence (per 1000) of physician-diagnosed type 1 diabetes in youth aged 0 through 19 years and type 2 diabetes in youth aged 10 through 19 years.

RESULTS

In 2001, 4958 of 3.3 million youth were diagnosed with type 1 diabetes for a prevalence of 1.48 per 1000 (95% CI, 1.44-1.52). In 2009, 6666 of 3.4 million youth were diagnosed with type 1 diabetes for a prevalence of 1.93 per 1000 (95% CI, 1.88-1.97). In 2009, the highest prevalence of type 1 diabetes was 2.55 per 1000 among white youth (95% CI, 2.48-2.62) and the lowest was 0.35 per 1000 in American Indian youth (95% CI, 0.26-0.47) and type 1 diabetes increased between 2001 and 2009 in all sex, age, and race/ethnic subgroups except for those with the lowest prevalence (age 0-4 years and American Indians). Adjusted for completeness of ascertainment, there was a 21.1% (95% CI, 15.6%-27.0%) increase in type 1 diabetes over 8 years. In 2001, 588 of 1.7 million youth were diagnosed with type 2 diabetes for a prevalence of 0.34 per 1000 (95% CI, 0.31-0.37). In 2009, 819 of 1.8 million were diagnosed with type 2 diabetes for a prevalence of 0.46 per 1000 (95% CI, 0.43-0.49). In 2009, the prevalence of type 2 diabetes was 1.20 per 1000 among American Indian youth (95% CI, 0.96-1.51); 1.06 per 1000 among black youth (95% CI, 0.93-1.22); 0.79 per 1000 among Hispanic youth (95% CI, 0.70-0.88); and 0.17 per 1000 among white youth (95% CI, 0.15-0.20). Significant increases occurred between 2001 and 2009 in both sexes, all age-groups, and in white, Hispanic, and black youth, with no significant changes for Asian Pacific Islanders and American Indians. Adjusted for completeness of ascertainment, there was a 30.5% (95% CI, 17.3%-45.1%) overall increase in type 2 diabetes.

CONCLUSIONS AND RELEVANCE

Between 2001 and 2009 in 5 areas of the United States, the prevalence of both type 1 and type 2 diabetes among children and adolescents increased. Further studies are required to determine the causes of these increases.

The typology of metabolic syndrome in the transition to adulthood

BACKGROUND

Metabolic syndrome (MetS) is a clustering of risks associated with cardiometabolic disease in adults. Obesity is considered the major etiologic factor. However, unlike obesity, the natural history of MetS as adolescents transition to adulthood is unknown.

OBJECTIVE

The purpose of this study was to characterize the typology of MetS as adolescents transition to young adulthood and to explore determinants of that typology.

DESIGN/PARTICIPANTS

A total of 458 participants from a school-based longitudinal cohort study of baseline 5th to 12th graders were followed for 9 years.

METHODS

Based on the presence or absence of MetS at study visits (year [Y] 1, Y4, Y8, and Y10), a MetS typology was defined, and its characteristics were explored using multinomial regression modeling.

RESULTS

Both obesity and MetS increased (obesity from 21.0% to 33.4% and MetS from 2.8% to 17.9%). MetS typology was as follows: never, 76.9%; incident, 16.4%; unstable/remitted, 5.7%; and persistent, 1.1%. Of Y1 MetS-positive cases, 61.5% remitted, as did 36.4% of Y4 MetS-positive cases and 25% of Y8 MetS-positive cases. Most incident cases (56.0%, n = 42) occurred in Y10; only 12% (n = 9) occurred in Y4. Obesity increased the odds of MetS (incident: odds ratio [OR] = 4.42, 95% confidence interval [CI] = 2.23-8.76; unstable/remitted: OR = 7.79, 95% CI = 3.12-19.41; persistent: OR = 31.36, 95% CI = 2.99-328.98). In addition, changes in body mass index over the study were associated with persistent (OR = 1.27, 95% CI = 1.03-1.56) and incident MetS (OR = 1.49, 95% CI = 1.31-1.71), but not unstable/remitted MetS (OR = 1.09, 95% CI = 0.99-1.19). Of note, body mass index increased for 77% of those with unstable/remitted MetS, including 90% (n = 9/10) of persistently obese youth with unstable/remitted MetS.

CONCLUSIONS

During the transition to adulthood, the diagnosis of MetS is highly unstable and fluctuates even among those who are obese and gaining weight.

Validation of pediatric diabetes case identification approaches for diagnosed cases by using information in the electronic health records of a large integrated managed health care organization

We explored the utility of different algorithms for diabetes case identification by using electronic health records. Inpatient and outpatient diagnosis codes, as well as data on laboratory results and dispensing of antidiabetic medications were extracted from electronic health records of Kaiser Permanente Southern California members who were less than 20 years of age in 2009. Diabetes cases were ascertained by using the SEARCH for Diabetes in Youth Study protocol and comprised the "gold standard." Sensitivity, specificity, positive and negative predictive values, accuracy, and the area under the receiver operating characteristic curve (AUC) were compared in 1,000 bootstrapped samples. Based on data from 792,992 youth, of whom 1,568 had diabetes (77.2%, type 1 diabetes; 22.2%, type 2 diabetes; 0.6%, other), case identification accuracy was highest in 75% of bootstrapped samples for those who had 1 or more outpatient diabetes diagnoses or 1 or more insulin prescriptions (sensitivity, 95.9%; positive predictive value, 95.5%; AUC, 97.9%) and in 25% of samples for those who had 2 or more outpatient diabetes diagnoses and 1 or more antidiabetic medications (sensitivity, 92.4%; positive predictive value, 98.4%; AUC, 96.2%). Having 1 or more outpatient type 1 diabetes diagnoses (International Classification of Diseases, Ninth Revision, Clinical Modification, code 250.x1 or 250.x3) had the highest accuracy (94.4%) and AUC (94.1%) for type 1 diabetes; the absence of type 1 diabetes diagnosis had the highest accuracy (93.8%) and AUC (93.6%) for identifying type 2 diabetes. Information in the electronic health records from managed health care organizations provides an efficient and cost-effective source of data for childhood diabetes surveillance.

Use of glycosylated hemoglobin increases diabetes screening for at-risk adolescents in primary care settings

OBJECTIVE

To examine rates of diabetes screening in obese adolescents in an ethnically diverse primary care health care system before and after an internal recommendation to use HbA1c-based screening.

RESEARCH DESIGN AND METHODS

Adolescents 12-18-years old with BMI > 95% were identified through electronic medical record review during two 18-month periods in 8 community health clinics and 13 school-based health centers: period 1 (P1, 19 April 2008 to 19 October 2009) and period 2 (P2, 3 May 2010 to 3 November 2011). Testing for diabetes in the 2 yr preceding the most recently elevated BMI was reviewed.

RESULTS

A total of 2870 obese adolescents were identified in P1 and 3940 in P2. Ethnicity was primarily Hispanic, with smaller populations of Black and White youth. The percent of obese teens screened for diabetes increased from 40% in P1 to 47% in P2. Use of HbA1c increased 493% during P2. Older teens (>15 yr), those seen during P2, and those with BMI ≥ 30 kg/m2 were more likely to be screened. Record review confirmed equal rates of type 2 diabetes in the two periods: 8 incident (0.7%) cases in P1 and 13 (0.7%) in P2.

CONCLUSIONS

The use of HbA1c, a non-fasting and logistically simpler test, was associated with increased diabetes screening in primary care. The percentage of screened patients with confirmed type 2 diabetes remained unchanged. Thus, despite potential pitfalls, the use of HbA1c for screening appears to be as successful as previous approaches in identifying adolescents with diabetes.

Global trends in the incidence and prevalence of type 2 diabetes in children and adolescents: a systematic review and evaluation of methodological approaches

AIMS/HYPOTHESIS

This study aimed to systematically review what has been reported on the incidence and prevalence of type 2 diabetes in children and adolescents, to scrutinise the methodological issues observed in the included studies and to prepare recommendations for future research and surveillances.

METHODS

PubMed, the Cochrane Database of Systematic Reviews, Scopus, EMBASE and Web of Science were searched from inception to February 2013. Population-based studies on incidence and prevalence of type 2 diabetes in children and adolescents were summarised and methodologically evaluated. Owing to substantial methodological heterogeneity and considerable differences in study populations a quantitative meta-analysis was not performed.

RESULTS

Among 145 potentially relevant studies, 37 population-based studies met the inclusion criteria. Variations in the incidence and prevalence rates of type 2 diabetes in children and adolescents were mainly related to age of the study population, calendar time, geographical regions and ethnicity, resulting in a range of 0-330 per 100,000 person-years for incidence rates, and 0-5,300 per 100,000 population for prevalence rates. Furthermore, a substantial variation in the methodological characteristics was observed for response rates (60-96%), ascertainment rates (53-99%), diagnostic tests and criteria used to diagnose type 2 diabetes.

CONCLUSIONS/INTERPRETATION

Worldwide incidence and prevalence of type 2 diabetes in children and adolescents vary substantially among countries, age categories and ethnic groups and this can be explained by variations in population characteristics and methodological dissimilarities between studies.

Socioeconomic status gradients in inflammation in adolescence

OBJECTIVE

To determine whether lower socioeconomic status (SES), broadly defined, is associated with increased inflammation in adolescence and whether adiposity mediates these relationships.

METHODS

Fasting blood samples from 941 non-Hispanic black and white adolescents enrolled in a suburban, Midwestern school district were assayed for proinflammatory biomarkers (interleukin-6 [IL-6], tumor necrosis factor α soluble receptor 2 fibrinogen). A parent reported objective SES (parent education [E1 ≤ high school, E2 = some college, E3 = college graduate, E4 = professional degree], household income), and youth perceived SES (PSES). Multivariable linear regressions assessed the relationship of SES measures to biomarkers adjusting for age, race, sex, and puberty status. In the final step, body mass index (BMI) z score (BMIz) was added to models, and Sobel tests were performed to assess mediation by adiposity.

RESULTS

Parent education was inversely associated with IL-6 (βE1 = .11, βE2 = .10, βE3 = .02; p < .001). This association was attenuated but remained significant after BMIz adjustment (p = .01). Sobel testing confirmed BMIz's partial mediating role (p < .001). Parent education was also inversely associated with sTNFR2 (βE1 = .03, βE2 = .02, βE3 = .001; p = .01); this relationship was mediated by BMIz. Although no main effect was noted for PSES, PSES by race interactions was observed for sTNFR2 (p = .02) and IL-6 (p = .06). High PSES was associated with lower sTNFR2 and IL-6 for white but not black youth. There were no associations with household income.

CONCLUSIONS

Social disadvantage, specifically low parent education, is associated with increased inflammation in adolescence. Adiposity explains some but not all associations, suggesting that other mechanisms link lower SES to inflammation. High PSES is associated with lower inflammation for white but not black youth.

Association of optimism with cardiometabolic risk in adolescents

PURPOSE

Dispositional optimism is a psychological trait associated with cardiovascular disease outcomes in adults. However, it is not known whether these associations are present in adolescents. We attempted to determine whether an association exits between optimism and 9 biomarkers of cardiometabolic risk during adolescence. Because cardiometabolic risk differs by race and ethnicity, we also explored whether race and ethnicity moderated the optimism-cardiometabolic risk relationship.

METHODS

This was a cross-sectional study of 529 non-Hispanic white and 421 non-Hispanic black seventh through 12th graders living in greater Cincinnati in 2001-2002. We measured dispositional optimism with the Life-Orientation Test-Revised as a single continuum and as separate optimism and pessimism dimensions. Multivariable regression analyses tested for associations between optimism and nine biomarkers of risk (interleukin-6, tumor necrosis factor-α, lipids, insulin, glucose, and fibrinogen), adjusting for age, gender, parent education, body mass index, smoking, and pubertal stage.

RESULTS

Dispositional optimism with the Life-Orientation Test-Revised as a single continuum was inversely associated with two risks (interleukin-6, β = -.03, p = .02; insulin, β = -.02, p = .01), but only among blacks. Optimism and pessimism were inversely related (R = -.27, p < .001) and both were higher in blacks than whites (p < .001). Optimism was directly associated with high-density lipoprotein among all subjects (β = .42, p = .03), and among blacks (β = .74, p = .02) but not whites. Among blacks, optimism was also inversely associated with interleukin-6 (β = -.07, p = .001) and triglycerides (β = -.02, p = .04). Pessimism was inversely associated with glucose, but only in whites (β = -.38, p = .03).

CONCLUSIONS

Associations between dispositional optimism and cardiometabolic risks are present in adolescence and vary by race and ethnicity. A better understanding of the natural history of these associations over the lifespan may help decrease disparities and prevent cardiometabolic disease.

Cost-effectiveness of screening strategies for identifying pediatric diabetes mellitus and dysglycemia

OBJECTIVE

To conduct a cost-effectiveness analysis of screening strategies for identifying children with type 2 diabetes mellitus and dysglycemia (prediabetes/diabetes).

DESIGN

Cost simulation study.

SETTING

A one-time US screening program.

STUDY PARTICIPANTS

A total of 2.5 million children aged 10 to 17 years.

INTERVENTION

Screening strategies for identifying diabetes and dysglycemia.

MAIN OUTCOME MEASURES

Effectiveness (proportion of cases identified), total costs (direct and indirect), and efficiency (cost per case identified) of each screening strategy based on test performance data from a pediatric cohort and cost data from Medicare and the US Bureau of Labor Statistics.

RESULTS

In the base-case model, 500 and 400 000 US adolescents had diabetes and dysglycemia, respectively. For diabetes, the cost per case was extremely high ($312 000-$831 000 per case identified) because of the low prevalence of disease. For dysglycemia, the cost per case was in a more reasonable range. For dysglycemia, preferred strategies were the 2-hour oral glucose tolerance test (100% effectiveness; $390 per case), 1-hour glucose challenge test (63% effectiveness; $571), random glucose test (55% effectiveness; $498), or a hemoglobin A1c threshold of 5.5% (45% effectiveness; $763). Hemoglobin A1c thresholds of 5.7% and 6.5% were the least effective and least efficient (ranges, 7%-32% and $938-$3370) of all strategies evaluated. Sensitivity analyses for diabetes revealed that disease prevalence was a major driver of cost-effectiveness. Sensitivity analyses for dysglycemia did not lead to appreciable changes in overall rankings among tests.

CONCLUSIONS

For diabetes, the cost per case is extremely high because of the low prevalence of the disease in the pediatric population. Screening for diabetes could become more cost-effective if dysglycemia is explicitly considered as a screening outcome.

A risk score for identifying overweight adolescents with dysglycemia in primary care settings

OBJECTIVE

To develop a clinical risk scoring system for identifying adolescents with dysglycemia (prediabetes or diabetes) who need further confirmatory testing and to determine whether the addition of non-fasting tests would improve the prediction of dysglycemia.

STUDY DESIGN

A sample of 176 overweight and obese adolescents (10-17 years) had a history/physical exam, a 2-h oral glucose tolerance test, and non-fasting tests [hemoglobin A1c, 1-h glucose challenge test (GCT), and random glucose test] performed. Given the low number of children with diabetes, we created several risk scoring systems combining the clinical characteristics with non-fasting tests for identifying adolescents with dysglycemia and compared the test performance.

RESULTS

Sixty percent of participants were white and 32% were black; 39.2% had prediabetes and 1.1% had diabetes. A basic model including demographics, body mass index percentile, family history of diabetes, and acanthosis nigricans had reasonable test performance [area under the curve (AUC), 0.75; 95% confidence interval (95% CI), 0.68-0.82]. The addition of random glucose (AUC, 0.81; 95% CI, 0.75-0.87) or 1-h GCT (AUC, 0.82; 95% CI, 0.75-0.88) to the basic model significantly improved the predictive capacity, but the addition of hemoglobin A1c did not (AUC, 0.76; 95% CI, 0.68-0.83). The clinical score thresholds to consider for the basic plus random glucose model are total score cutoffs of 60 or 65 (sensitivity 86% and 65% and specificity 60% and 78%, respectively) and for the basic plus 1-h GCT model are total score cutoffs of 50 or 55 (sensitivity 87% and 73% and specificity 59% and 76%, respectively).

CONCLUSIONS

Pending a validation in additional populations, a risk score combining the clinical characteristics with non-fasting test results may be a useful tool for identifying children with dysglycemia in the primary care setting.

Novel variations in the adiponectin gene (ADIPOQ) may affect distribution of oligomeric complexes

Adiponectin is an obesity related protein that mediates the risk of type 2 diabetes in obese individuals with its anti-inflammatory and insulin-sensitizing properties. To date, five functional variations have been identified in the adiponectin gene. However, these variations are rare, and fail to fully explain adiponectin variability, suggesting unidentified causal variations exist. Thus, our objective was to identify novel, potentially functional amino acid-changing variations in ADIPOQ exonic regions and relate them to oligomeric forms of adiponectin in serum. We sequenced ADIPOQ exons in 30 adolescents chosen from a school-based cohort based on serum adiponectin and insulin levels. Four coding region changes were identified: a methionine initiation skip (MIS), P32L, R55C, and Y111H, of which R55C and Y111H have been previously identified. Individuals with the novel variations and R55C had low levels of adiponectin and decreased adiponectin oligomerization compared to adolescents with similar body mass index and insulin levels. Further, bioinformatic analysis predicted putative functionality of these variations. In our study, Y111H was unrelated to total circulating adiponectin or adiponectin oligomerization. Given the disruption of adiponectin oligomerization in the individuals with MIS, P32L, and R55C coding changes, these variations may lead to increased metabolic disease risk and warrant further examination in larger cohorts.

IGF receptor gene variants in normal adolescents: effect on stature

OBJECTIVE

IGF1 is essential for human growth and mediates its effects through the type 1 IGF receptor (IGF1R). Our objective was to determine the frequency of certain previously reported IGF1R gene variants in the normal population and their effect on stature.

DESIGN

A cross-sectional study was conducted in a population of 2500 children enrolled in public school grades 5 through 12 for whom DNA and anthropometric data were available. Subjects were genotyped at five previously reported loci that affect receptor abundance or function.

METHODS

The frequency of the following IGF1R variants Arg108Gln, Lys115Asn, Arg59stop, Arg481Gln, and Arg605His was measured by a PCR-based assay. Circulating concentrations of IGF1 or IGF binding protein-3 (IGFBP3) were measured by ELISA in those affected and matched controls.

RESULTS

A scan of 1300 subjects detected none with Arg108Gln, Lys115Asn, or Arg59stop mutations. In contrast, nucleotide changes leading to heterozygosity at codon 605 were identified in nine of 2500 subjects and six of 1800 subjects at codon 481. These individuals were, on average, 4 cm shorter than the others. There were no differences in circulating concentrations of IGF1 or IGFBP3 between those with the gene variants and controls matched for sex, ethnicity, age, and BMI.

CONCLUSION

Rare IGF1R variants exerting a moderate effect on stature are present in the general population, supporting the importance of IGF1R function in growth control and indicating that variation in height within healthy individuals may be explained, in some cases, by larger effects of a small subset of gene variants.

Adolescent Sex Differences in Adiponectin Are Conditional on Pubertal Development and Adiposity

OBJECTIVE

Adiponectin is an adipose tissue protein with important insulin-sensitizing, anti-inflammatory, and cardioprotective properties but is paradoxically lower in obese individuals. Sex differences in adiponectin have been reported in adults and adolescents but not in prepubertal children. In this study, we hypothesized that sex differences in adiponectin would develop during puberty and would be influenced by level of adiposity.

RESEARCH METHODS AND PROCEDURES

Adiponectin levels were measured in 1196 white and African-American adolescents. Insulin resistance was estimated using the homeostasis model (HOMA-IR). Demographic, developmental, and metabolic variables, including interactions with adiposity measurements, were evaluated for independent relationships with adiponectin levels.

RESULTS

Overall, adiponectin levels varied significantly by sex, race, adiposity, and puberty stage. Significant sex differences in adiponectin developed after the onset of puberty, particularly in lean adolescents. Adolescent boys had lower adiponectin levels in post-puberty compared with pre-puberty (p = 0.01) and had lower levels than girls in both puberty and post-puberty (both p < 0.001), after adjusting for race, BMI z-score, and natural logarithm-(HOMA-IR). Sex differences were also conditional on adiposity level, with significant sex differences among lean (p < 0.001) but not among non-lean (p = 0.16) adolescents. Adiponectin levels in girls decreased more with increasing adiposity than in boys (p = 0.004), but only marginally so after standardizing for girls' higher mean adiponectin level (p = 0.11).

DISCUSSION

Sex differences in adiponectin are dependent on both puberty stage and adiposity in adolescents, such that by post-puberty, non-lean boys exhibit the lowest levels of adiponectin.

A prospective study of psychological distress and weight status in adolescents/young adults

BACKGROUND

The obesity-psychological distress relationship remains controversial.

PURPOSE

This study aims to assess whether adolescents' psychological distress was associated with body mass index (BMI) class membership determined by latent class analysis.

METHODS

Distress (anxiety, depression) and BMI were measured annually for 4 years in 1,528 adolescents. Growth mixture modeling derived latent BMI trajectory classes for models with 2-11 classes. The relationship of distress to class membership was examined in the best-fitting model using vector generalized linear regression.

RESULTS

BMI trajectories were basically flat. The five-class model [normal weight (48.8%), overweight (36.7%), obese who become overweight (3.7%), obese (9.4%), and severely obese (1.3%)] was the preferred model (Bayesian information criterion = 22789.2, df = 31; ρ = 0.84). Greater distress was associated with higher baseline BMI and, therefore, class membership.

CONCLUSIONS

Psychological distress is associated with higher BMI class during adolescence. To determine whether distress "leads" to greater weight gain may require studies of younger populations.

Requested meals versus scheduled meals

BACKGROUND

Scheduled meals are considered to be equivalent to those requested by the infant (null hypothesis). In adults, we have found high blood glucose before scheduled meals and low blood glucose after recognition of validated initial hunger. Low preprandial blood glucose is associated with a decrease in energy intake and body weight both in adults who are overtly overweight and in those who are of normal weight with insulin resistance (hidden overweight). In this study, we investigated the validity of the null hypothesis between scheduled and requested meals in 2-year-old infants with chronic nonspecific diarrhea.

METHODS

We trained a "recognizing request" meal pattern in 70 mother-infant pairs. The trained meal pattern consisted of administering food after a first request that we validated by blood glucose measurement in the hospital laboratory. Using a 7-day food diary, mothers reported preprandial blood glucose measurements for their infants three times a day. We assessed mean preprandial blood glucose, daily energy intake, days with diarrhea, blood parameters, and anthropometry before training and 4 months after training, and compared the results with measurements in 73 randomly selected untrained controls.

RESULTS

In the trained group, there was a decrease in mean blood glucose from 86.9 ± 9.4 mg/dL to 76.4 ± 6.7 mg/dL (P < 0.0001), as well as a decrease in energy intake and days with diarrhea in comparison with control infants who maintained scheduled meals. Only two of 21 infants who had a mean blood glucose lower than 81.2 mg/dL at recruitment showed a statistically significant decrease in mean blood glucose, whereas 36 of 49 infants above this cutoff level showed a statistically significant decrease after training (Chi-square test, P < 0.0001).

CONCLUSION

Requested meals are associated with low preprandial blood glucose, significantly lower energy intake, and recovery from diarrhea, whereas scheduled meals are associated with high blood glucose, higher energy intake, and persistence of diarrhea. The disparities in blood glucose levels and energy intake disprove the null hypothesis, suggesting the need for a change from scheduled to requested meals early on in food administration, ie, during the neonatal period.

Estimated morbidity and mortality in adolescents and young adults diagnosed with Type 2 diabetes mellitus

AIMS

To estimate remaining life expectancy (RLE), quality-adjusted life expectancy (QALE), causes of death and lifetime cumulative incidence of microvascular/macrovascular complications of diabetes for youths diagnosed with Type 2 diabetes.

METHODS

A Markov-like computer model simulated the life course for a hypothetical cohort of adolescents/young adults in the USA, aged 15-24 years, newly diagnosed with Type 2 diabetes following either conventional or intensive treatment based on the UK Prospective Diabetes Study. Outcomes included RLE, discounted QALE in quality-adjusted life years (QALYs), cumulative incidence of microvascular/macrovascular complications and causes of death.

RESULTS

Compared with a mean RLE of 58.6 years for a 20-year-old in the USA without diabetes, conventional treatment produced an average RLE of 43.09 years and 22.44 discounted QALYs. Intensive treatment afforded an incremental 0.98 years and 0.44 discounted QALYs. Intensive treatment led to lower lifetime cumulative incidence of all microvascular complications and lower mortality from microvascular complications (e.g. end-stage renal disease (ESRD) death 19.4% vs. 25.2%). Approximately 5% with both treatments had ESRD within 25 years. Lifetime cumulative incidence of coronary heart disease (CHD) increased with longer RLE and greater severity of CHD risk factors. Incorporating disutility (loss in health-related quality of life) of intensive treatment resulted in net loss of QALYs.

CONCLUSIONS

Adolescents/young adults with Type 2 diabetes lose approximately 15 years from average RLE and may experience severe, chronic complications of Type 2 diabetes by their 40s. The net clinical benefit of intensive treatment may be sensitive to preferences for treatment. A comprehensive management plan that includes early and aggressive control of cardiovascular risk factors is likely needed to reduce lifetime risk of CHD.

Which obese youth are at increased risk for type 2 diabetes? Latent class analysis and comparison with diabetic youth

PURPOSE

Most obese youth screened for diabetes have normal fasting glucose levels. Identification of youth with increased risk for type 2 diabetes (T2D) is needed within this large population to guide further management.

METHODS

Retrospective chart review was performed for obese youth, 8-20 yr old, who met American Diabetes Association criteria for screening (OB) or had T2D (D). Measures included body mass index z-score (BMIz) and homeostasis model assessment of insulin resistance (HOMA-IR) by fasting plasma glucose (FPG) and insulin. Statistics compared OB with D and further examined OB by latent class analysis (LCA).

RESULTS

Normal FPG was found in 91.5% of all obese youth (OBt n = 94) Comparison of OB with normal FPG (OBng; n = 86) and D (n = 44) was significant for family history of T2D (p = 0.008) without other associations. Evaluation of OBng by LCA showed three classes with increasing BMIz and HOMA-IR. Class 3 (32.5%; BMIz 2.66 ± 0.38; HOMA-IR 6.72 ± 2.29) differed from classes 1 and 2 (p < 0.05), and was associated with family history of T2D.

CONCLUSION

Currently recommended screening of obese youth by FPG is normal in 91.5%, but lacks further information to detect increased risk for youth-onset T2D. Evaluation of obese youth by LCA identified one third (class 3) in whom the combination of higher levels of BMIz, HOMA-IR, and family history suggests the greatest risk for T2D and targets them for further evaluation and intensive preventative management.

Evaluation of nonfasting tests to screen for childhood and adolescent dysglycemia

OBJECTIVE

To assess performance of nonfasting tests to screen children for dysglycemia (prediabetes or diabetes).

RESEARCH DESIGN AND METHODS

This was a cross-sectional study of 254 overweight or obese (BMI ≥85th percentile) children aged 10-17 years. Subjects came for two visits to a clinical research unit. For visit one, they arrived fasting and a 2-h glucose tolerance test and HbA(1c) and fructosamine testing were performed. For visit two, they arrived nonfasting and had a random plasma glucose, a 1-h 50-g nonfasting glucose challenge test (1-h GCT), and urine dipstick performed. The primary end point was dysglycemia (fasting plasma glucose ≥100 mg/dL or a 2-h postglucose ≥140 mg/dL). Test performance was assessed using receiver operating characteristic (ROC) curves and calculations of area under the ROC curve.

RESULTS

Approximately one-half of children were female, 59% were white, and 30% were black. There were 99 (39%) cases of prediabetes and 3 (1.2%) cases of diabetes. Urine dipstick, HbA(1c) (area under the curve [AUC] 0.54 [95% CI 0.47-0.61]), and fructosamine (AUC 0.55 [0.47-0.63]) displayed poor discrimination for identifying children with dysglycemia. Both random glucose (AUC 0.66 [0.60-0.73]) and 1-h GCT (AUC 0.68 [0.61-0.74]) had better levels of test discrimination than HbA(1c) or fructosamine.

CONCLUSIONS

HbA(1c) had poor discrimination, which could lead to missed cases of dysglycemia in children. Random glucose or 1-h GCT may potentially be incorporated into clinical practice as initial screening tests for prediabetes or diabetes and for determining which children should undergo further definitive testing.

Optimism and the socioeconomic status gradient in adolescent adiposity

PURPOSE

To assess whether dispositional optimism is associated with adiposity and to explore whether dispositional optimism mediates the relationship between parent education and adiposity (body mass index [BMI] z-score).

METHODS

Multivariate regression analyses of data were collected from 1,298 non-Hispanic black and white adolescents aged 12-19 years from a single Midwestern public school district.

RESULTS

Less optimistic adolescents had higher BMI z-scores (r = -.09, p < .001). Addition of dispositional optimism to the regression model caused an approximately 10% attenuation of the parent education and BMI z-score relationship. Sobel tests confirmed that this attenuation indicated partial mediation.

CONCLUSION

Lower dispositional optimism is associated with higher adiposity and this association accounts for some of the influence of parent education on adolescent adiposity.

Impact of obesity on metabolic syndrome among adolescents as compared with adults in Korea

PURPOSE

This study aimed to estimate the prevalence of metabolic syndrome (MetS) in adolescents and adults and to compare the impact of body mass index (BMI) on MetS between adolescents and adults in Korea.

MATERIALS AND METHODS

Data were used from 6,186 subjects aged 10 years or more who representatively participated in the Third Korean National Health and Nutrition Examination Survey. Body composition, blood test, and health behavioral factors were measured. We used the definition of MetS from the modified the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) for adolescents and the NCEP-ATP Ⅲ for adults.

RESULTS

The prevalence of MetS was 6.4 (95% CI 4.5-8.4) and 22.3 (95% CI 20.8-23.8) in adolescents and adults, respectively. The prevalence of MetS among normal, overweight and obese body types for both adolescents and adults differed significantly (p<0.001). After adjustment for covariates, the odds ratios (ORs) of obese and overweight body types on MetS compared with normal BMI in adolescents were 28.1 (95% CI 11.4-69.1) and 8.7 (95% CI 2.3-33.1), respectively. The ORs of obesity on MetS were 32.0 (95% CI 7.5-136.9), 32.2 (95% CI 12.8-80.8), 16.2 (95% CI 9.4-27.9), 7.6 (95% CI 4.7-12.2) and 9.9 (95% CI 6.8-14.6) for subjects in their 20's, 30's, 40's, 50's and older than 60, in order.

CONCLUSION

We found that the prevalence of MetS increased with age and was more prevalent in males. Moreover, the group younger than 39 years of age had a higher chance of having MetS than the group older than 40 years of age. Weight control is more vital in the earlier stages of life for the prevention and management of MetS.

Low Social Status Markers: Do They Predict Depressive Symptoms in Adolescence?

Some markers of social disadvantage are associated robustly with depressive symptoms among adolescents: female gender and lower socioeconomic status (SES), respectively. Others are associated equivocally, notably Black v. White race/ethnicity. Few studies examine whether markers of social disadvantage by gender, SES, and race/ethnicity jointly predict self-reported depressive symptoms during adolescence; this was our goal. Secondary analyses were conducted on data from a socioeconomically diverse community-based cohort study of non-Hispanic Black and White adolescents (N = 1,263, 50.4% female). Multivariable general linear models tested if female gender, Black race/ethnicity, and lower SES (assessed by parent education and household income), and their interactions predicted greater depressive symptoms reported on the Center for Epidemiological Studies-Depression scale. Models adjusted for age and pubertal status. Univariate analyses revealed more depressive symptoms in females, Blacks, and participants with lower SES. Multivariable models showed females across both racial/ethnic groups reported greater depressive symptoms; Blacks demonstrated more depressive symptoms than did Whites but when SES was included this association disappeared. Exploratory analyses suggested Blacks gained less mental health benefit from increased SES. However there were no statistically significant interactions among gender, race/ethnicity, or SES. Taken together, we conclude that complex patterning among low social status domains within gender, race/ethnicity, and SES predicts depressive symptoms among adolescents.

Diagnosis of diabetes using hemoglobin A1c: should recommendations in adults be extrapolated to adolescents?

OBJECTIVE

To compare test performance of hemoglobin A1c (HbA1c) for detecting diabetes mellitus/pre-diabetes for adolescents versus adults in the United States.

STUDY DESIGN

Individuals were defined as having diabetes mellitus (fasting plasma glucose [FPG] ≥ 126 mg/dL; 2-hour plasma glucose (2-hr PG) ≥ 200 mg/dL) or pre-diabetes (100 ≤ FPG < 126 mg/dL; 140 ≤ 2-hr PG < 200 mg/dL. HbA1c test performance was evaluated with receiver operator characteristic (ROC) analyses.

RESULTS

Few adolescents had undiagnosed diabetes mellitus (n = 4). When assessing FPG to detect diabetes, an HbA1c of 6.5% had sensitivity rates of 75.0% (30.1% to 95.4%) and 53.8% (47.4% to 60.0%) and specificity rates of 99.9% (99.5% to 100.0%) and 99.5% (99.3% to 99.6%) for adolescents and adults, respectively. Additionally, when assessing FPG to detect diabetes mellitus, an HbA1c of 5.7% had sensitivity rates of 5.0% (2.6% to 9.2%) and 23.1% (21.3% to 25.0%) and specificity rates of 98.3% (97.2% to 98.9%) and 91.1% (90.3% to 91.9%) for adolescents and adults, respectively. ROC analyses suggested that HbA1c is a poorer predictor of diabetes mellitus (area under the curve, 0.88 versus 0.93) and pre-diabetes (FPG area under the curve 0.61 versus 0.74) for adolescents compared with adults. Performance was poor regardless of whether FPG or 2-hr PG measurements were used.

CONCLUSIONS

Use of HbA1c for diagnosis of diabetes mellitus and pre-diabetes in adolescents may be premature, until information from more definitive studies is available.

Hostility and adiposity mediate disparities in insulin resistance among adolescents and young adults

OBJECTIVE

This study explores whether the relationship between lower socioeconomic status and insulin resistance in adolescents is mediated by both physiological and psychological factors associated with increased cardiometabolic risk.

STUDY DESIGN

School-based longitudinal cohort study of 1222 healthy, non-Hispanic black and white teens. Parent education (PE), youth-specific Cook-Medley hostility scale, waist circumference, height, weight, pubertal status, and fasting plasma insulin (FPI) were measured and FPI reassessed 1 year later. Regression analyses utilizing bootstrapping (n=2000) were used to estimate the direct and indirect effects of PE on FPI and assess the role of hostility and adiposity while adjusting for covariates.

RESULTS

Lower PE predicted higher FPI (B=-1.52, P=.003), as did hostility (B=.19, P=.002) and adiposity (waist circumference B=.44, P<.001, BMI B=.98, P<.001). The effect of PE on FPI was mediated by both hostility and adiposity. When adiposity and hostility were accounted for, the effect of PE on FPI decreased by 32% (B=-1.04, P=.04); the total indirect estimate was -.485 (95% CI, -.652, -.041). Hostility accounted for 36% of the meditational effect.

CONCLUSIONS

Lower PE influences insulin resistance through adiposity and hostility. Thus, interventions to reduce health disparities associated with insulin resistance should consider both physiological and psychological approaches.

Association of FTO gene variants with adiposity in African-American adolescents

The prevalence of obesity continues to increase significantly, with the largest rise in the African-American adolescents. Genetic contributions to obesity are being identified with the advent of genome-wide association studies (GWAS). Specifically, variants of the fat mass and obesity associated (FTO) gene have been associated with obesity in populations of European descent. The studies in African Americans have been inconclusive. To further evaluate the association of the FTO gene and adiposity in African Americans, we genotyped 47 single-nucleotide polymorphisms (SNPs), including seven SNPs previously reported to be significant in the literature in a cohort consisting of 561 non-Hispanic white and 497 African-American individuals. Analysis of our data showed 17 SNPs to be associated with BMI Z-score (BMI-Z) in our study population. The strongest association was found in the African Americans. The most significant SNP was rs8057044, which was associated with BMI-Z in the African Americans (P = 0.00054). SNP rs9939609 was found to be significant in the non-Hispanic white population (P = 0.028). Our data confirm the association between FTO and adiposity suggesting that FTO is a childhood obesity susceptibility gene. Our data also identify a novel SNP of the FTO gene (rs8057044) that is associated with measures of adiposity in the African-American population.

Type 2 diabetes in children and adolescents

The emergence of Type 2 diabetes (T2D) in children and adolescents parallels the rising rates of childhood obesity. As a condition of impaired insulin sensitivity and relative insulin deficiency resulting in hyperglycemia, T2D has a complex underlying physiology that is reflected by the multiple approaches used to optimize medical care and prevent the myriad of diabetes-related complications. T2D diagnosed in children and adolescents represents a distinct and challenging condition to evaluate and treat. Here, we highlight the epidemiology, pathophysiology, risk factors, clinical presentation and diagnosis, treatment and public health impact of T2D in children and adolescents.

Insulin resistance and metabolic syndrome in the pediatric population

The metabolic syndrome is a constellation of specific anthropometric, physiological, and biochemical abnormalities predisposing affected individuals to the development of diabetes and cardiovascular disease. The syndrome is well described in the adult literature. However, its description in the pediatric literature is more limited. Due in large part to the normal physiological changes that occur in children and adolescents with respect to growth and puberty, investigators have also struggled to establish a standard definition of the syndrome in the pediatric age group, hindering coordinated research efforts. However, whatever definition of the syndrome is used, the prevalence of the metabolic syndrome in the pediatric age group has increased worldwide. Insulin resistance is the principal metabolic abnormality that is common to the development of the metabolic syndrome in both children and adults. This review summarizes current research regarding the pathophysiology of insulin resistance and how this may contribute to specific abnormalities seen in children and adolescents with the metabolic syndrome. Specifically, insulin resistance in pediatric patients is correlated with cardiovascular risk factors such as elevated blood pressure, dyslipidemia, and type 2 diabetes mellitus, all of which are significant risk factors for adult disease. In addition, current treatment and prevention strategies, including lifestyle modifications, pharmacologic agents, and certain surgical therapies, are highlighted. The need for collaborative changes at the family, school, city, state, and national levels to address the growing prevalence of the metabolic syndrome in the pediatric age group is also reviewed.

Increased prevalence of obesity and glucose intolerance in youth treated with second-generation antipsychotic medications

OBJECTIVE

To compare the rates of obesity, impaired fasting glucose (IFG), and type 2 diabetes between second-generation antipsychotic (SGA)-treated and -naive youth.

METHODS

A retrospective chart review was conducted for all child and adolescent psychiatry emergency admissions over 2.5 years. Data collected included age, sex, psychiatric diagnosis, medications, height, weight, fasting glucose, and lipid profile. Body mass index (BMI) was standardized for age and sex and converted to a z score. Overweight was defined as a BMI between the 85th and 95th percentile and obese as a BMI at the 95th percentile or greater for age and sex. The 2007 American Diabetes Association criteria for IFG and type 2 diabetes were used.

RESULTS

Among the 432 admissions, 167 (39%) had both height and weight measured, and 145 (34%) had fasting glucose measured. The mean zBMI was higher in the SGA-treated (n = 68), compared with the SGA-naive group (n = 99) (mean difference 0.81; 95% CI 0.46 to 1.16). In the SGA-treated group, 31% were obese and 26% were overweight, compared with 15% and 8%, respectively, in the SGA-naive group (P < 0.01). In the SGA-treated group (n = 65), 21.5% had IFG or type 2 diabetes, compared with 7.5% in the SGA-naive group (n = 80) (P = 0.01).

CONCLUSIONS

Youth treated with SGAs have significantly higher rates of obesity and glucose intolerance than SGA-naive youth. These data emphasize the need for consistent metabolic monitoring of youth with psychiatric disorders who are prescribed SGAs.