Rationale, design, methodology and sample characteristics for the family partners for health study: a cluster randomized controlled study.

BACKGROUND: Young children who are overweight are at increased risk of becoming obese and developing type 2 diabetes and cardiovascular disease later in life. Therefore, early intervention is critical. This paper describes the rationale, design, methodology, and sample characteristics of a 5-year cluster randomized controlled trial being conducted in eight elementary schools in rural North Carolina, United States. METHODS/DESIGN: The first aim of the trial is to examine the effects of a two-phased intervention on weight status, adiposity, nutrition and exercise health behaviors, and self-efficacy in overweight or obese 2nd, 3 rd, and 4th grade children and their overweight or obese parents. The primary outcome in children is stabilization of BMI percentile trajectory from baseline to 18 months. The primary outcome in parents is a decrease in BMI from baseline to 18 months. Secondary outcomes for both children and parents include adiposity, nutrition and exercise health behaviors, and self-efficacy from baseline to 18 months. A secondary aim of the trial is to examine in the experimental group, the relationships between parents and children's changes in weight status, adiposity, nutrition and exercise health behaviors, and self-efficacy. An exploratory aim is to determine whether African American, Hispanic, and non-Hispanic white children and parents in the experimental group benefit differently from the intervention in weight status, adiposity, health behaviors, and self-efficacy.A total of 358 African American, non-Hispanic white, and bilingual Hispanic children with a BMI ≥ 85th percentile and 358 parents with a BMI ≥ 25 kg/m² have been inducted over 3 1/2 years and randomized by cohort to either an experimental or a wait-listed control group. The experimental group receives a 12-week intensive intervention of nutrition and exercise education, coping skills training and exercise (Phase I), 9 months of continued monthly contact (Phase II) and then 6 months (follow-up) on their own. Safety endpoints include adverse event reporting. Intention-to-treat analysis will be applied to all data. DISCUSSION: Findings from this trial may lead to an effective intervention to assist children and parents to work together to improve nutrition and exercise patterns by making small lifestyle pattern changes. TRIAL REGISTRATION: NCT01378806.

Simple modeling allows prediction of steady-state glucose disposal rate from early data in hyperinsulinemic glucose clamps.

After a constant insulin infusion is initiated, determination of steady-state conditions for glucose infusion rates (GIR) typically requires >or=3 h. The glucose infusion follows a simple time-dependent rise, reaching a plateau at steady state. We hypothesized that nonlinear fitting of abbreviated data sets consisting of only the early portion of the clamp study can provide accurate estimates of steady-state GIR. Data sets from two independent laboratories were used to develop and validate this approach. Accuracy of the predicted steady-state GDR was assessed using regression analysis and Altman-Bland plots, and precision was compared by applying a calibration model. In the development data set (n = 88 glucose clamp studies), fitting the full data set with a simple monoexponential model predicted reference GDR values with good accuracy (difference between the 2 methods -0.37 mg x kg(-1) x min(-1)) and precision [root mean square error (RMSE) = 1.11], validating the modeling procedure. Fitting data from the first 180 or 120 min predicted final GDRs with comparable accuracy but with progressively reduced precision [fitGDR-180 RMSE = 1.27 (P = NS vs. fitGDR-full); fitGDR-120 RMSE = 1.56 (P < 0.001)]. Similar results were obtained with the validation data set (n = 183 glucose clamp studies), confirming the generalizability of this approach. The modeling approach also derives kinetic parameters that are not available from standard approaches to clamp data analysis. We conclude that fitting a monoexponential curve to abbreviated clamp data produces steady-state GDR values that accurately predict the GDR values obtained from the full data sets, albeit with reduced precision. This approach may help reduce the resources required for undertaking clamp studies.

Oral glucosamine for 6 weeks at standard doses does not cause or worsen insulin resistance or endothelial dysfunction in lean or obese subjects.

Glucosamine is a popular nutritional supplement used to treat osteoarthritis. Intravenous administration of glucosamine causes insulin resistance and endothelial dysfunction. However, rigorous clinical studies evaluating the safety of oral glucosamine with respect to metabolic and cardiovascular pathophysiology are lacking. Therefore, we conducted a randomized, placebo-controlled, double-blind, crossover trial of oral glucosamine at standard doses (500 mg p.o. t.i.d.) in lean (n = 20) and obese (n = 20) subjects. Glucosamine or placebo treatment for 6 weeks was followed by a 1-week washout and crossover to the other arm. At baseline, and after each treatment period, insulin sensitivity was assessed by hyperinsulinemic-isoglycemic glucose clamp (SI(Clamp)) and endothelial function evaluated by brachial artery blood flow (BAF; Doppler ultrasound) and forearm skeletal muscle microvascular recruitment (ultrasound with microbubble contrast) before and during steady-state hyperinsulinemia. Plasma glucosamine pharmacokinetics after oral dosing were determined in each subject using a high-performance liquid chromatography method. As expected, at baseline, obese subjects had insulin resistance and endothelial dysfunction when compared with lean subjects (SI(Clamp) [median {25th-75th percentile}] = 4.3 [2.9-5.3] vs. 7.3 [5.7-11.3], P < 0.0001; insulin-stimulated changes in BAF [% over basal] = 12 [-6 to 84] vs. 39 [2-108], P < 0.04). When compared with placebo, glucosamine did not cause insulin resistance or endothelial dysfunction in lean subjects or significantly worsen these findings in obese subjects. The half-life of plasma glucosamine after oral dosing was approximately 150 min, with no significant changes in steady-state glucosamine levels detectable after 6 weeks of therapy. We conclude that oral glucosamine at standard doses for 6 weeks does not cause or significantly worsen insulin resistance or endothelial dysfunction in lean or obese subjects.

Metabolic effects of chronic cannabis smoking.

OBJECTIVE: We examined if chronic cannabis smoking is associated with hepatic steatosis, insulin resistance, reduced ß-cell function, or dyslipidemia in healthy individuals. RESEARCH DESIGN AND METHODS: In a cross-sectional, case-control study, we studied cannabis smokers (n = 30; women, 12; men, 18; 27 ± 8 years) and control subjects (n = 30) matched for age, sex, ethnicity, and BMI (27 ± 6). Abdominal fat depots and intrahepatic fat content were quantified by magnetic resonance imaging and proton magnetic resonance spectroscopy, respectively. Insulin-sensitivity indices and various aspects of ß-cell function were derived from oral glucose tolerance tests (OGTT). RESULTS: Self-reported cannabis use was: 9.5 (2-38) years; joints/day: 6 (3-30) [median (range)]. Carbohydrate intake and percent calories from carbohydrates, but not total energy intake, were significantly higher in cannabis smokers. There were no group differences in percent total body fat, or hepatic fat, but cannabis smokers had a higher percent abdominal visceral fat (18 ± 9 vs. 12 ± 5%; P = 0.004). Cannabis smokers had lower plasma HDL cholesterol (49 ± 14 vs. 55 ± 13 mg/dL; P = 0.02), but fasting levels of glucose, insulin, total cholesterol, LDL cholesterol, triglycerides, or free fatty acids (FFA) were not different. Adipocyte insulin resistance index and percent FFA suppression during an OGTT was lower (P < 0.05) in cannabis smokers. However, oral glucose insulin sensitivity index, measures of ß-cell function, or incretin concentrations did not differ between the groups. CONCLUSIONS: Chronic cannabis smoking was associated with visceral adiposity and adipose tissue insulin resistance but not with hepatic steatosis, insulin insensitivity, impaired pancreatic ß-cell function, or glucose intolerance.

Cocoa consumption for 2 wk enhances insulin-mediated vasodilatation without improving blood pressure or insulin resistance in essential hypertension.

BACKGROUND: Essential hypertension is characterized by reciprocal relations between endothelial dysfunction and insulin resistance. Cocoa flavanols stimulate production of the vasodilator nitric oxide from vascular endothelium. OBJECTIVE: The objective was to test the hypothesis that consumption of cocoa may simultaneously lower blood pressure, improve endothelial dysfunction, and ameliorate insulin resistance in subjects with essential hypertension. DESIGN: We conducted a randomized, placebo-controlled, double-blind, crossover trial of a flavanol-rich cocoa drink (150 mL twice a day, approximately 900 mg flavanols/d) in individuals with essential hypertension (n = 20). Antihypertensive medications were discontinued before study enrollment. After a 7-d cocoa-free run-in period, cocoa or flavanol-poor placebo (approximately 28 mg flavanols/d) treatment for 2 wk was followed by a 1-wk washout and then crossover to the other treatment arm. Blood pressure was measured thrice weekly. At baseline and after each treatment period, we assessed insulin sensitivity (hyperinsulinemic-isoglycemic glucose clamp) and insulin-stimulated changes in brachial artery diameter and forearm skeletal muscle capillary recruitment (Doppler ultrasound with or without microbubble contrast). RESULTS: Cocoa treatment for 2 wk increased insulin-stimulated changes in brachial artery diameter when compared with placebo [median percentage increase from baseline (25th-75th percentile): 8.3 (4.2-11.3) compared with 5.9 (-0.3 to 9.6); P < 0.04]. Nevertheless, cocoa treatment did not significantly reduce blood pressure or improve insulin resistance and had no significant effects on skeletal muscle capillary recruitment, circulating plasma concentrations of adipocytokines, or endothelial adhesion molecules. CONCLUSIONS: Daily consumption of flavanol-rich cocoa for 2 wk is not sufficient to reduce blood pressure or improve insulin resistance in human subjects with essential hypertension. This trial was registered at clinicaltrials.gov as NCT00099476.

High-dose oral vitamin C partially replenishes vitamin C levels in patients with Type 2 diabetes and low vitamin C levels but does not improve endothelial dysfunction or insulin resistance.

Endothelial dysfunction is a hallmark of Type 2 diabetes related to hyperglycemia and oxidative stress. Nitric oxide-dependent vasodilator actions of insulin may augment glucose disposal. Thus endothelial dysfunction may worsen insulin resistance. Intra-arterial administration of vitamin C improves endothelial dysfunction in diabetes. In the present study, we investigated effects of high-dose oral vitamin C to alter endothelial dysfunction and insulin resistance in Type 2 diabetes. Plasma vitamin C levels in 109 diabetic subjects were lower than healthy (36 +/- 2 microM) levels. Thirty-two diabetic subjects with low plasma vitamin C (<40 microM) were subsequently enrolled in a randomized, double-blind, placebo-controlled study of vitamin C (800 mg/day for 4 wk). Insulin sensitivity (determined by glucose clamp) and forearm blood flow in response to ACh, sodium nitroprusside (SNP), or insulin (determined by plethysmography) were assessed before and after 4 wk of treatment. In the placebo group (n = 17 subjects), plasma vitamin C (22 +/- 3 microM), fasting glucose (159 +/- 12 mg/dl), insulin (19 +/- 7 microU/ml), and SI(Clamp) [2.06 +/- 0.29 x 10(-4) dl x kg(-1) x min(-1)/(microU/ml)] did not change significantly after placebo treatment. In the vitamin C group (n = 15 subjects), basal plasma vitamin C (23 +/- 2 microM) increased to 48 +/- 6 microM (P < 0.01) after treatment, but this was significantly less than that expected for healthy subjects (>80 microM). No significant changes in fasting glucose (156 +/- 11 mg/dl), insulin (14 +/- 2 microU/ml), SI(Clamp) [2.71 +/- 0.46 x 10(-4) dl x kg(-1) x min(-1)/(microU/ml)], or forearm blood flow in response to ACh, SNP, or insulin were observed after vitamin C treatment. We conclude that high-dose oral vitamin C therapy, resulting in incomplete replenishment of vitamin C levels, is ineffective at improving endothelial dysfunction and insulin resistance in Type 2 diabetes.

Imagent improves endocardial border delineation, inter-reader agreement, and the accuracy of segmental wall motion assessment.

BACKGROUND: This study was conducted to assess the ability of a new echocardiographic contrast agent, Imagent (perflexane lipid microspheres; Alliance Pharmaceutical Corp., San Diego, CA), to improve endocardial border delineation (EBD) and assessment of segmental wall motion (SWM). This was achieved by analysis of inter-reader agreement by echocardiography and comparison with an independent imaging technique, magnetic resonance imaging (MRI). METHODS: Two separate, independent, prospective, randomized, controlled, multicenter trials were conducted at 26 centers and included a total of 409 efficacy-evaluable patients. In Study A 206 patients were randomized to receive either Imagent or saline and in Study B, 203 patients received Imagent with a subset imaged by both echocardiography and MRI. All patients were required to have suboptimal baseline images using fundamental imaging. Images were optimized at baseline prior to contrast and the settings maintained post-contrast. Imagent, a suspension of perfluorohexane-filled spheres with flexible lipid shells, was administered as an IV bolus at 0.125 mg/kg body weight. Gated MRI studies were performed within 48 hours of dosing in a subset of 26 subjects. Six expert independent blinded readers reviewed unpaired noncontrast and contrast exams and scored EBD and SWM. Analysis of inter-reader agreement was performed by comparing the SWM score (1 to 5) recorded by each reader pair. In addition, unanimity between readers for SWM was evaluated. For comparison to MRI, the results from echo readers 4, 5, and 6 were each compared with a single independent MRI reader. RESULTS: The patients enrolled in these clinical trials displayed markedly suboptimal images with 49% and 71% (Study A and Study B) of the segments determined by the readers to be suboptimal prior to contrast administration. All readers recorded statistically significant (P < 0.0001) improvement in total EBD scores following the administration of Imagent. Comparison of noncontrast SWM scores for each pair of echo readers resulted in agreement in an average of 39%, of segments in Study A, and 31% of the segments in Study B. Use of Imagent improved agreement in SWM scores to 65% in Study A, and 48% of segments in Study B (P < 0.0001) for all reader pairs in both studies. Reader unanimity in SWM scores increased from 13% to 41% of the segments with the administration of Imagent. Blinded review of the noncontrast echo examinations resulted in agreement with MRI derived SWM scores in 15% of the segments. The administration of Imagent improved this agreement to 47%, of the segments (P < pr = 0.0005 for each blinded reader). CONCLUSIONS: Use of Imagent during echocardiographic imaging improves EBD, providing a significant improvement in inter-reader agreement in SWM evaluation with echo and greater than a threefold improvement in SWM scoring accuracy with MRI.

In vivo lung deposition of hollow porous particles from a pressurized metered dose inhaler.

PURPOSE: PulmoSphere particles are specifically engineered for delivery by the pulmonary route with a hollow and porous morphology, physical diameters < 5 microm, and low tap densities (circa 0.1 g x cm(-3)). Deposition of PulmoSphere particles in the human respiratory tract delivered by pressurized metered dose inhaler (pMDI) was compared with deposition of a conventional micronized drug pMDI formulation. METHODS: Nine healthy nonsmoking subjects (5 male, 4 female) completed a two-way crossover gamma scintigraphic study, assessing the lung and oropharyngeal depositions of albuterol sulfate, formulated as 99mTc-radiolabeled PulmoSphere particles or micronized particles (Ventolin Evohaler, GlaxoSmithKline, Ltd.) suspended in HFA-134a propellant. RESULTS: Mean (standard deviation) lung deposition, (% ex-valve dose) was doubled for the PulmoSphere formulation compared with Evohaler pMDI (28.5 (11.3) % vs. 14.5 (8.1) %, P < 0.01), whereas oropharyngeal deposition was reduced (42.6 (9.0) % vs. 72.0 (8.0) %, P < 0.01). Both PulmoSphere and Evohaler pMDIs gave uniform deposition patterns within the lungs. CONCLUSIONS: These data provided "proof of concept" in vivo for the PulmoSphere technology as a method of improving targeting of drugs to the lower respiratory tract from pMDIs, and suggested that the PulmoSphere technology may also be suitable for the delivery of systemically acting molecules absorbed via the lung.