The relationship between sleep-disordered breathing, blood pressure, and urinary cortisol and catecholamines in children.

STUDY OBJECTIVES: Hypertension is a complication of obstructive sleep apnea (OSA) syndrome in adults. A correlation between OSA syndrome and elevated blood pressure (BP) is suggested in children, but its pathogenesis remains unclear. Our aim was to study the effects of sleep and sleep apnea on BP and sympathetic nervous system activation as measured by serum cortisol and urinary catecholamines. We hypothesized that children with OSA syndrome would have higher BP, urinary catecholamines, and cortisol compared with controls. METHODS: We measured BP during polysomnography in 78 children with suspected sleep-disordered breathing and 18 nonsnoring controls. BP was measured during wakefulness and every 30-60 minutes throughout the night. All participants had 24-hour urinary catecholamine and free cortisol collections 48 hours before polysomnography. RESULTS: BP varied with sleep stage; it was highest during wakefulness and N1 and lowest during non-rapid eye movement stage 3. Children classified as high apnea-hypopnea index (AHI) snorers (AHI >5 events/h) had a greater prevalence of systolic hypertension (57%) than low-AHI snorers (22%) and nonsnoring controls (22%; P = .04). The high-AHI snorers also had higher diastolic BP (P < .02) as well as blunted nocturnal diastolic BP changes during sleep (P = .02) compared with low-AHI snorers (AHI <5 events/h). Twenty-hour urinary free cortisol and 24-hour urinary catecholamines were not associated with BP. CONCLUSIONS: BP in children varies with sleep stage. OSA is associated with systolic hypertension, higher BP during rapid eye movement sleep, as well as elevation of diastolic BP and blunted BP changes with sleep.

A cross-sectional study of vitamin D and insulin resistance in children.

OBJECTIVE: Vitamin D deficiency is common and has been associated with several non-bone/calcium related outcomes. The objective was to determine the association between serum 25-hydroxyvitamin D (25-OH-D) and fasting glucose, insulin and insulin sensitivity in obese and non-obese children. PATIENTS/SETTING/DESIGN: Cross-sectional study of 85 children aged 4-18 years recruited from the local Philadelphia community and Sleep Center. MAIN OUTCOME MEASURES: Fasting blood glucose, insulin and 25-OH-D were measured. Insulin resistance was calculated using homeostasis model assessment (HOMA). Body mass index standard deviation scores (BMI-Z) and pubertal stage were determined. Multivariable linear regression was used to determine factors associated with decreased 25-OH-D and to determine the association of vitamin D with HOMA. RESULTS: Median 25-OH-D was 52 nmol/l (IQR 34-76). 26% of subjects were vitamin D sufficient (25-OH-D ≥75 nmol/l), 27% had intermediate values (50-75 nmol/l) and 47% were insufficient (25-50 nmol/l) or frankly deficient (<25 nmol/l). In the multivariable model, older age, higher BMI-Z and African-American race were all negatively associated with 25-OH-D; summer was positively associated with 25-OH-D. Lower 25-OH-D was associated with higher fasting blood glucose, insulin and HOMA after adjustment for puberty and BMI-Z. CONCLUSION: Low 25-OH-D, common in the paediatric population at risk for diabetes (older children, African-Americans, children with increasing BMI-Z) is associated with worse insulin resistance.

Elevation of 1-hour plasma glucose during oral glucose tolerance testing is associated with worse pulmonary function in cystic fibrosis.

OBJECTIVE: Cystic fibrosis (CF)-related diabetes (CFRD) is associated with declining pulmonary function and increased mortality. During oral glucose tolerance testing (OGTT), CFRD is defined by 2-h plasma glucose (PG2). We hypothesized PG elevations during OGTT resolving by 2 h, not meeting CFRD criteria, influence pulmonary function in CF. Thus we investigated the frequency of elevated 1-h OGTT PG (PG1) and its relationship with pulmonary function. RESEARCH DESIGN AND METHODS: Retrospective review of OGTTs was performed between August 2005 (annual screening initiation) and June 2008 at Children's Hospital of Philadelphia CF Center. First-time, well state OGTTs (PG0, PG1, PG2) were analyzed. Additional data collected were: percent predicted forced expiratory volume in 1 s (FEV(1)), BMI percentile, lung bacterial colonization, age, and sex. OGTTs were categorized as normal (PG2 <140 mg/dL), impaired glucose tolerance (IGT) (PG2 140-199 mg/dL), CFRD (PG2 ≥ 200 mg/dL), and indeterminate glycemia (INDET) (PG1 ≥ 200 mg/dL and PG2 <140 mg/dL). Frequency of PG1 ≥ 140 but <200 mg/dL was also noted. Multivariable linear regression was used to assess associations between percent predicted FEV(1), BMI percentile, and OGTT PG. RESULTS: OGTTs (101) were available (59 male/42 female; age 5.8-22 years, percent predicted FEV(1) = 94.5 ± 18%, BMI percentile = 52 ± 25%). With the use of PG2, 91 OGTT were normal, eight were IGT, and two were CFRD. With the use of PG1 (n = 89), 39 OGTT were normal, 36 were PG1 ≥ 140 <200 mg/dL, and 14 were PG1 ≥ 200 mg/dL. PG1 was negatively associated with percent predicted FEV(1), adjusting for BMI percentile (P = 0.009, R(2) 0.13). Percent predicted FEV(1) was not associated with PG0, PG2, age, sex, or lung bacterial colonization. CONCLUSIONS: PG elevations at nontraditional OGTT times are common in CF. The association of increasing PG1 with worse pulmonary function suggests early PG abnormalities may be deleterious or an early marker for worsening disease and will be missed if CFRD diagnosis focuses on PG2.

Needle anxiety in children with type 1 diabetes and their mothers.

PURPOSE: To report the prevalence of fear, distress, pain, and level of cooperation with insulin injections and blood glucose fingersticks in children with newly diagnosed diabetes and their mothers, and the association with diabetes control. STUDY DESIGN AND METHODS: Forty-six subjects (23 children and mother pairs) completed the Perceptions of Insulin Shots and Fingersticks Survey at diagnosis and 6 to 9 months later. Standard descriptive statistics, Fisher's exact tests, and Spearman correlation coefficients were used to analyze the data. Scores were analyzed for associations with age and hemoglobin A1c as a marker of diabetes control. RESULTS: More young children as compared to older subjects reported fear and pain with injections and fingersticks. A high percentage of mothers reported high fear and distress with needles at diagnosis. Although most improve, 13.6% of mothers continued to report high fear and distress 6 to 9 months later. Mothers' continued report of high distress correlated with the poor cooperation of children, which correlated with poorer diabetes control. CLINICAL IMPLICATIONS: Nurses should incorporate assessment and intervention for needle anxiety in children and parents at diagnosis of diabetes through informal interview or formal survey. Nurses can effectively incorporate coping strategies into their teaching of parents and children to administer injections and fingersticks.

Catecholamines, adiponectin, and insulin resistance as measured by HOMA in children with obstructive sleep apnea.

INTRODUCTION: Obstructive sleep apnea (OSA) has been implicated in the pathophysiology of metabolic syndrome. Its contribution to insulin resistance is complicated by obesity and puberty. We hypothesized that OSA is associated with worse insulin resistance and lower adiponectin after adjustment for obesity and puberty and that catecholamines might mediate these changes. METHODS: Normal controls and children with suspected OSA were recruited and categorized as pubertal or prepubertal. Overnight polysomnography (PSG) was performed. Subjects were categorized as OSA for total apnea hypopnea index (Total-AHI) > or = 1.5 events/h. Fasting blood glucose, insulin, adiponectin, and 24-hour urinary catecholamines were obtained. Homeostatic model assessment of insulin resistance (HOMA) was calculated. The independent effects of OSA upon HOMA, adiponectin, and urinary catecholamines following adjustment for body mass index (BMI) were determined. RESULTS (median; min, max): Subjects (n = 98, 42F; 11 +/- 4 years, 37 prepubertal) were generally overweight (BMI-Z = 2.1; -3, 4.1) and had wide-ranging insulin sensitivities (HOMA = 2.7; 0.5, 27) and PSG parameters (Total-AHI = 1.6; 0, 185). The risks of elevated insulin (P = 0.04) and HOMA (P = 0.05) were higher in OSA vs non OSA obese pubertal children. Polysomnographic markers of OSA, including Total-AHI (P = 0.001, R2 = 0.32), were negatively associated with adiponectin in pubertal children. Total-AHI and oxygen desaturation were associated with higher urinary normetanephrine and norepinephrine. CONCLUSIONS: In obese pubertal children, OSA was associated with worse insulin resistance. Worsening OSA was associated with lower adiponectin and increasing urinary catecholamines. Whether OSA directly lowers adiponectin and aggravates a predisposition to insulin resistance is unknown, but these preliminary findings highlight the importance of further studying pediatric OSA.