Kerryn Chisholm

Researching Effective Strategies to Improve Insulin Sensitivity in Children and Teenagers - RESIST. A randomised control trial investigating the effects of two different diets on insulin sensitivity in young people with insulin resistance and/or pre-diabetes.

BackgroundConcomitant with the rise in childhood obesity there has been a significant increase in the number of adolescents with clinical features of insulin resistance and prediabetes. Clinical insulin resistance and prediabetes are likely to progress to type 2 diabetes and early atherosclerosis if not targeted for early intervention. There are no efficacy trials of lifestyle intervention in this group to inform clinical practice. The primary aim of this randomised control trial (RCT) is to determine the efficacy and effectiveness of two different structured lifestyle interventions differing in diet composition on insulin sensitivity, in adolescents with clinical insulin resistance and/or prediabetes treated with metformin.Methods/designThis study protocol describes the design of an ongoing RCT. We are recruiting 108 (54 each treatment arm) 10 to 17 year olds with clinical features of insulin resistance and/or prediabetes, through physician referral, into a multi-centred RCT. All participants are prescribed metformin and participate in a diet and exercise program. The lifestyle program is the same for all participants except for diet composition. The diets are a high carbohydrate, low fat diet and a moderate carbohydrate, increased protein diet.The program commences with an intensive 3 month dietary intervention, implemented by trained dietitians, followed by a 3 month intensive gym and home based exercise program, supervised by certified physical trainers. To measure the longer term effectiveness, after the intensive intervention trial participants are managed by either their usual physician or study physician and followed up by the study dietitians for an additional 6 months. The primary outcome measure, change in insulin sensitivity, is measured at 3, 6 and 12 months.DiscussionClinical insulin resistance and prediabetes in the paediatric population are rapidly emerging clinical problems with serious health outcomes. With appropriate management these conditions are potentially reversible or at least their progression can be delayed. This research study is the first trial designed to provide much needed data on the effective dietary management for this cohort. This study will inform clinical practice guidelines for adolescents with clinical insulin resistance and may assist in preventing metabolic complications, type 2 diabetes and early cardiovascular disease.Trial registrationAustralian and New Zealand Clinical Trials Registration Number ACTRN12608000416392

Optimal Macronutrient Content of the Diet for Adolescents With Prediabetes; RESIST a Randomised Control Trial

CONTEXT Prediabetes and clinical insulin resistance in adolescents are rapidly emerging clinical problems with serious health outcomes. OBJECTIVE The objective of this study was to determine the efficacy of 2 structured lifestyle interventions, both differing in diet macronutrient composition, on insulin sensitivity. DESIGN This study was a randomized controlled trial, known as Researching Effective Strategies to Improve Insulin Sensitivity in Children and Teenagers, in 2 hospitals in Sydney, Australia. PARTICIPANTS Participants included overweight or obese 10- to 17-year-olds with either prediabetes and/or clinical features of insulin resistance. INTERVENTION At baseline adolescents were prescribed metformin and randomized to a structured diet, which was either high carbohydrate or moderate carbohydrate with increased protein. The program commenced with a 3-month dietary intervention, with the addition of an exercise intervention in the next 3 months. OUTCOMES The outcomes included an insulin sensitivity, anthropometry, and cardiometabolic profile at 6 months. RESULTS One hundred eleven subjects (66 girls) were recruited and 98 subjects (58 girls) completed the 6-month intervention. After 3 months the mean insulin sensitivity index increased by 0.3 [95% confidence interval (CI) 0.2-0.4]. After 6 months the mean insulin (picomoles per liter) to glucose ratio (millimoles per liter) decreased by 7.2 [95%CI -12.0 to -2.3], body mass index, expressed as a percentage of the 95th centile, decreased by 9% (95% CI -3 to -15), but there was no significant change in the lipids. There were no significant differences in outcomes between the diet groups at any time point. CONCLUSIONS These results are in contrast with our hypothesis that adolescents randomized to the increased protein diet would have better outcomes. Further strategies are required to better address prediabetes and clinical features of insulin resistance in adolescents.

Improved insulin sensitivity and body composition, irrespective of macronutrient intake, after a 12 month intervention in adolescents with pre-diabetes; RESIST a randomised control trial

BackgroundA higher protein to carbohydrate ratio in the diet may potentiate weight loss, improve body composition and cardiometabolic risk, including glucose homeostasis in adults. The aim of this randomised control trial was to determine the efficacy of two structured lifestyle interventions, differing in dietary macronutrient content, on insulin sensitivity and body composition in adolescents. We hypothesised that a moderate-carbohydrate (40-45% of energy), increased-protein (25-30%) diet would be more effective than a high-carbohydrate diet (55-60%), moderate-protein (15%) diet in improving outcomes in obese, insulin resistant adolescents.MethodsObese 10–17 year olds with either pre-diabetes and/or clinical features of insulin resistance were recruited at two hospitals in Sydney, Australia. At baseline adolescents were prescribed metformin and randomised to one of two energy restricted diets. The intervention included regular contact with the dietician and a supervised physical activity program. Outcomes included insulin sensitivity index measured by an oral glucose tolerance test and body composition measured by dual-energy x-ray absorptiometry at 12 months.ResultsOf the 111 adolescents recruited, 85 (77%) completed the intervention. BMI expressed as a percentage of the 95th percentile decreased by 6.8% [95% CI: −8.8 to −4.9], ISI increased by 0.2 [95% CI: 0.06 to 0.39] and percent body fat decreased by 2.4% [95% CI: −3.4 to −1.3]. There were no significant differences in outcomes between diet groups at any time.ConclusionWhen treated with metformin and an exercise program, a structured, reduced energy diet, which is either high-carbohydrate or moderate-carbohydrate with increased-protein, can achieve clinically significant improvements in obese adolescents at risk of type 2 diabetes.Trial registrationAustralian New Zealand Clinical Trail Registry ACTRN12608000416392. Registered 25 August 2008.

Can early weight loss, eating behaviors and socioeconomic factors predict successful weight loss at 12- and 24-months in adolescents with obesity and insulin resistance participating in a randomised controlled trial?

BackgroundLifestyle interventions in adolescents with obesity can result in weight loss following active intervention but individual responses vary widely. This study aimed to identify predictors of weight loss at 12- and 24-months in adolescents with obesity and clinical features of insulin resistance.MethodsAdolescents (n = 111, 66 girls, aged 10–17 years) were participants in a randomised controlled trial, the RESIST study, examining the effects of two diets differing in macronutrient content on insulin sensitivity. Eighty-five completed the 12-month program and 24-month follow-up data were available for 42 adolescents. Change in weight was determined by BMI expressed as a percentage of the 95th percentile (BMI95). The study physician collected socioeconomic data at baseline. Physical activity and screen time, and psychological dimensions of eating behavior were self-reported using the validated CLASS and EPI-C questionnaires, respectively. Stepwise multiple regressions were conducted to identify models that best predicted change in BMI95 at 12- and 24-months.ResultsMean BMI95 was reduced at 12-months compared with baseline (mean difference [MD] ± SE: -6.9 ± 1.0, P < 0.001) but adolescents had significant re-gain from 12- to 24-months (MD ± SE: 3.7 ± 1.5, P = 0.017). Participants who achieved greater 12-month weight loss had: greater 3-month weight loss, a father with a higher education, lower baseline external eating and parental pressure to eat scores and two parents living at home. Participants who achieved greater 24-month weight loss had: greater 12-month weight loss and a lower baseline emotional eating score.ConclusionsEarly weight loss is consistently identified as a strong predictor of long-term weight loss. This could be because early weight loss identifies those more motivated and engaged individuals. Patients who have baseline factors predictive of long-term weight loss failure may benefit from additional support during the intervention. Additionally, if a patient does not achieve early weight loss, further support or transition to an alternate intervention where they may have increased success may be considered.Trial registrationAustralian New Zealand Clinical Trial Registration Number (ACTRN) 12608000416392 https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=83071

Nutritional adequacy of diets for adolescents with overweight and obesity: considerations for dietetic practice

Background/Objectives:Adolescents have unique nutrient requirements due to rapid growth and development. High rates of obesity in adolescents require a variety of diet interventions to achieve weight loss under clinical supervision. The aim of this study is to examine the nutritional adequacy of energy-restricted diets for adolescents.Subjects/Methods:Three popular diets were modelled for 7 days and assessed by comparing the nutrient profile to the Australian Nutrient Reference Values. Three diets were: (1) a standard energy restricted diet based on current dietary guidelines; (2) a modified carbohydrate diet; and (3) a modified alternate day fasting diet.Results:Initial modelling revealed limiting nutrients (that is, not meeting the recommended intakes) across the diets. Subsequent modelling was required to achieve nutritional adequacy for all three diets. The dietary guidelines diet design met most nutrient targets except essential fatty acids before subsequent modelling, however this diet also provided the highest energy (8.8 vs 8.0 MJ and 6.8 MJ for the modified carbohydrate and modified alternate day fasting diet, respectively).Conclusions:Energy-restricted diets need careful consideration to meet nutritional requirements of adolescents. A variety of eating patterns can be adapted to achieve nutritional adequacy and energy restriction, however health practitioners need to consider adequacy when prescribing diet interventions for weight loss during adolescence.

Tertiary-level management of overweight and obese children and adolescents: Does intensive dietetic intervention have a positive impact on weight control?

Aim Tertiary clinical management of paediatric obesity is complex and the best treatment model of care is unknown. We aimed to ascertain if a prescriptive nutritional intervention in a tertiary dietetic clinic resulted in a reduction in body mass index (BMI) z-score. Methods Data (age, gender, anthropometry, clinic visits (number, timing) ) were collected on all patients between June 2005–September 2009 and intention to treat analyses were carried out by using linear mixed models. Results For attendees, significant reductions in BMI z-scores occurred in boys after the third clinic appointment (P = 0.04) and in girls after the fifth appointment (P = 0.046). Final mean BMI z-score reduction was 0.28 ± 0.09 for boys and 0.24 ± 0.12 for girls. A significant reduction in waist to height ratio (WHER) for girls (from mean 0.62 ± 0.06 to 0.54 ± 0.04) was achieved by the fifth visit (P < 0.001). Conclusions Prescriptive nutritional intervention in a tertiary dietetic clinical setting resulted in a significant reduction in BMI z-scores in both boys and girls evident by the third and fifth clinical appointments (contacts), respectively. No correlation was found between intensity of appointments in terms of length of time between clinic visits, age or initial BMI of the patient and reduction in BMI z-score. These findings reinforce that multiple appointments are required to produce a beneficial effect.