Obesity Genes and Weight Loss During Lifestyle Intervention in Children With Obesity

IMPORTANCE

Genome-wide association studies have identified genetic loci influencing obesity risk in children. However, the importance of these loci in the associations with weight reduction through lifestyle interventions has not been investigated in large intervention trials.

OBJECTIVE

To evaluate the associations between various obesity susceptibility loci and changes in body weight in children during an in-hospital, lifestyle intervention program.

DESIGN, SETTING, AND PARTICIPANTS

Long-term Effects of Lifestyle Intervention in Obesity and Genetic Influence in Children (LOGIC), an interventional prospective cohort study, enrolled 1429 children with overweight or obesity to participate in an in-hospital lifestyle intervention program. Genotyping of 56 validated obesity single-nucleotide variants (SNVs) was performed, and the associations between the SNVs and body weight reduction during the intervention were evaluated using linear mixed-effects models for each SNV. The LOGIC study was conducted from January 6, 2006, to October 19, 2013; data analysis was performed from July 15, 2015, to November 6, 2016.

EXPOSURES

A 4- to 6-week standardized in-hospital lifestyle intervention program (daily physical activity, calorie-restricted diet, and behavioral therapy).

MAIN OUTCOMES AND MEASURES

The association between 56 obesity-relevant SNVs and changes in body weight and body mass index.

RESULTS

Of 1429 individuals enrolled in the LOGIC Study, 1198 individuals (mean [SD] age, 14.0 [2.2] years; 670 [56%] girls) were genotyped. A mean (SD) decrease was noted in body weight of -8.7 (3.6) kg (95% CI, -15.7 to -1.8 kg), and body mass index (calculated as weight in kilograms divided by height in meters squared) decreased by -3.3 (1.1) (95% CI, -5.4 to -1.1) (both P < .05). Five of 56 obesity SNVs were statistically significantly associated with a reduction of body weight or body mass index (all P < 8.93 × 10-4 corresponding to Bonferroni correction for 56 tests). Compared with homozygous participants without the risk allele, homozygous carriers of the rs7164727 (LOC100287559: 0.42 kg; 95% CI, 0.31-0.53 kg, P = 4.00 × 10-4) and rs12940622 (RPTOR: 0.35 kg; 95% CI, 0.18-0.52 kg; P = 1.86 × 10-5) risk alleles had a lower reduction of body weight, whereas carriers of the rs13201877 (IFNGR1: 0.65 kg; 95% CI, 0.51-0.79 kg; P = 2.39 × 10-5), rs10733682 (LMX1B: 0.45 kg; 95% CI, 0.27-0.63 kg; P = 6.37 × 10-4), and rs2836754 (ETS2: 0.56 kg; 95% CI, 0.38-0.74 kg; P = 1.51 × 10-4) risk alleles were associated with a greater reduction of body weight after adjustment for age and sex.

CONCLUSIONS AND RELEVANCE

Genes appear to play a minor role in weight reduction by lifestyle in children with overweight or obesity. The findings suggest that environmental, social, and behavioral factors are more important to consider in obesity treatment strategies.

Uphill walking: Biomechanical demand on the lower extremities of obese adolescents

The number of obesity prevalence in adolescents is still increasing. Obesity treatment programs typically include physical activity with walking being recommended as appropriate activity, but limited information exists on the demand uphill walking places on the joint loading and power of obese adolescents. Therefore, the purpose of this study was to investigate the effect of different inclinations on step characteristics, sagittal and frontal joint angles, joint moments and joint power of obese adolescents in comparison to their normal-weight peers. Eleven obese (14.5±1.41 years, BMI: 31.1±3.5kg/m²) and eleven normal-weight adolescents (14.3±1.86 years, BMI: 19.0±1.7kg/m²) walked with 1.11m/s on a ramp with two imbedded force plates (AMTI, 1000Hz) at three inclinations (level, 6°, 12°). Kinematic data were collected via an infrared-camera motion system (Vicon, 250Hz). The two-way (inclination, group) ANOVA indicated a significant effect of inclination on almost all variables analysed, with the hip joint being the most affected by inclination, followed by the knee and ankle joint. The obese participants additionally spent less time in swing phase, walked with an increased knee flexion and valgus angle and an increased peak hip flexion and adduction moment. Hip joint power of obese adolescents was especially in the steepest inclination significantly increased compared to their normal-weight peers. Obese adolescents demonstrate increased joint loading compared to their normal-weight peers and in combination with a musculoskeletal malalignment they might be prone to an increased overuse injury risk.

Changing Characteristics of Obese Children and Adolescents Entering Pediatric Lifestyle Intervention Programs in Germany over the Last 11 Years: An Adiposity Patients Registry Multicenter Analysis of 65,453 Children and Adolescents

OBJECTIVE

To examine whether characteristics of children and adolescents who start lifestyle intervention (LI) for obesity in Germany changed over the last decade.

METHODS

65,453 subjects (<21 years) from the APV database (Adiposity Patients Registry) with a BMI ≥ 90th percentile were included (years 2005-2015). Logistic regression models (confounders: age, sex, migration background) were created for overweight, obesity, extreme obesity, and obesity-related comorbidities. Comorbidities were further adjusted for weight category. Results were stratified by inpatient or outpatient care.

RESULTS

Extreme obesity was found to be more frequent at the onset of LI (2005: 11.6; 2015: 12.7%) with a similar trend in subgroups (p < 0.001). Obesity increased (2005: 50.3%; 2015: 55.1%), and overweight decreased (2005: 34.1%; 2015: 29.0%) in the whole study population. Trends were similar for inpatient or outpatient care (all p < 0.001). Hypertension increased from 45.7% to 49.2% in the whole study population, and similar data were obtained in the subgroup of inpatients (both p < 0.0001). Dyslipidemia increased in all patients (2005: 21.9%; 2015: 28.0%) and in inpatients (2005: 20.2%; 2015: 25.7%; both p < 0.0001). Abnormal carbohydrate metabolism rose in all patients (from 5.2 to 6.4%; p = 0.0002) without significant trends in subgroups.

CONCLUSION

During the last decade, children and adolescents presented with higher BMI SDS at the onset of LI and the proportion with obesity-related comorbidities increased. Particularly the presence of comorbidities differed between outpatients and inpatients.

Mitochondrial Haplogroup T Is Associated with Obesity in Austrian Juveniles and Adults

Background

Recent publications have reported contradictory data regarding mitochondrial DNA (mtDNA) variation and its association with body mass index. The aim of the present study was to compare the frequencies of mtDNA haplogroups as well as control region (CR) polymorphisms of obese juveniles (n = 248) and obese adults (n = 1003) versus normal weight controls (n_juvenile = 266, n_adults = 595) in a well-defined, ethnically homogenous, age-matched comparative cohort of Austrian Caucasians.

Methodology and Principal Findings

Using SNP analysis and DNA sequencing, we identified the nine major European mitochondrial haplogroups and CR polymorphisms. Of these, only the T haplogroup frequency was increased in the juvenile obese cohort versus the control subjects [11.7% in obese vs. 6.4% in controls], although statistical significance was lost after adjustment for sex and age. Similar data were observed in a local adult cohort, in which haplogroup T was found at a significantly higher frequency in the overweight and obese subjects than in the normal weight group [9.7% vs. 6.2%, p = 0.012, adjusted for sex and age]. When all obese subjects were considered together, the difference in the frequency of haplogroup T was even more clearly seen [10.1% vs. 6.3%, p = 0.002, OR (95% CI) 1.71 (1.2–2.4), adjusted for sex and age]. The frequencies of the T haplogroup-linked CR polymorphisms C16294T and the C16296T were found to be elevated in both the juvenile and the adult obese cohort compared to the controls. Nevertheless, no mtDNA haplogroup or CR polymorphism was robustly associated with any of several investigated metabolic and cardiovascular parameters (e.g., blood pressure, blood glucose concentration, triglycerides, cholesterol) in all obese subjects.

Conclusions and Significance

By investigation of this large ethnically and geographically homogenous cohort of Middle European Caucasians, only mtDNA haplogroup T was identified as an obesity risk factor.

Health-related quality of life and physical activity in children and adolescents 2 years after an inpatient weight-loss program

OBJECTIVES

To investigate changes in health-related quality of life (HRQOL), body mass index (BMI), physical activity, and sedentary behavior at 24 months after an inpatient weight-loss program and to examine correlations between changes in HRQOL and BMI or physical activity.

STUDY DESIGN

This prospective study included 707 overweight and obese individuals (mean age, 14 ± 2 years; 57% girls) participating in a 4- to 6-week inpatient weight-loss program, 381 of whom completed a 24-month follow-up. HRQOL, physical activity, sedentary behavior, and BMI were assessed at baseline, at discharge, and at 6, 12, and 24 months after starting therapy. Longitudinal analyses were conducted using repeated-measures mixed models, adjusted for age, sex, and baseline outcome and accounting for attrition over time.

RESULTS

All variables improved over treatment and 6-month follow-up (P < .05). At 24 months, overall HRQOL indicated improvements relative to baseline (3 points on a scale of 0-100; 95% CI, 1.68-4.47; P < .001). Of the 6 HRQOL domains, the greatest improvement was observed for self-esteem (11 points; 95% CI, 8.40-13.14; P < .001). BMI was 0.5 kg/m(2) lower than at baseline (95% CI, -0.92 to -0.02; P = .04). Long-term changes in physical activity explained 30% of the variation in overall HRQOL (P = .01), and change in BMI was not associated with a change in HRQOL.

CONCLUSIONS

This inpatient weight-loss program was associated with positive changes in HRQOL over the long term, with particular improvements in self-esteem. The results indicate the potential role of physical activity in improving HRQOL without a substantial change in body composition.

The cardio-metabolic risk of moderate and severe obesity in children and adolescents

OBJECTIVE

To compare the cardio-metabolic risk profile between moderately obese and severely obese children and adolescents.

STUDY DESIGN

Cross-sectional study involving 463 obese 6- to 19-year-olds who were referred to an inpatient weight-loss program. Anthropometric data were assessed and fasting blood samples were analyzed for lipid and glucose metabolism, adipokines, and inflammatory markers. Moderately obese individuals (percentiles corresponding to body mass index ≥ 30 to 35 kg/m(2) at age 18 years) and severely obese individuals (percentiles corresponding to body mass index ≥ 35 kg/m(2) at age 18 years) were defined by sex and age-specific cut-offs according to the International Obesity Task Force.

RESULTS

The prevalence of the metabolic syndrome was three times higher in severely obese individuals compared with those who are moderately obese. Mean values for proinsulin, insulin, homeostatic model assessment-insulin resistance, triglycerides, and interleukin-6 were 30%-50% higher in severe obesity compared with moderate obesity. Concentrations of leptin and high-sensitive C-reactive protein were about 1.5-fold higher, adiponectin levels were 12% lower, and resistin levels 10% higher in severely obese individuals compared with moderately obese (all P < .001).

CONCLUSION

Severely obese individuals have a markedly more unfavorable cardio-metabolic risk profile than those who are moderately obese. The results of this study underscore the substantial effect of severe obesity on health and highlights that these children need to receive particular attention regarding obesity treatment.

Leptin, adiponectin, and short-term and long-term weight loss after a lifestyle intervention in obese children

OBJECTIVE

In overweight children, high leptin levels are independently associated with higher risk for cardiovascular disease, whereas adiponectin seems to be protective against type 2 diabetes and atherosclerosis. The study examines the predictive value of leptin for weight loss after a 4- to 6-wk inpatient therapy and again after 1 y; as well as the association among weight loss, leptin, and adiponectin levels and changes in cardiometabolic risk factors after therapy.

METHODS

Body mass index (BMI), blood pressure, Tanner stage, and cardiometabolic risk factors were studied in 402 children (59.2% females, 13.9 ± 2.3 y, BMI 33.8 ± 5.7 kg/m(2)) before and after a 4-to 6-wk inpatient intervention (exercise, diet, and behavioral therapy) and BMI 1 y later (n = 206).

RESULTS

BMI was reduced from 33.8 ± 5.7 to 30.5 ± 5.1 kg/m(2) (P < 0.001) during the lifestyle intervention and remained unchanged after 1 y. Baseline BMI was positively associated with leptin (r = 0.60; P < 0.001) and cardiometabolic risk factors (blood pressure, high-density lipoprotein [HDL] cholesterol, triglycerides). Baseline leptin was associated with BMI and triglycerides (r = 0.39; P < 0.001), baseline adiponectin with HDL-cholesterol (r = 0.40; P < 0.001). Baseline BMI explained 40.7% of the variance in weight loss during therapy. The combination of BMI, sex, and leptin explained 50.4% of the variance. Neither BMI nor leptin predicted weight changes over the long term.

CONCLUSIONS

Overweight children maintained a substantial amount of weight loss after participation in a short-term inpatient lifestyle intervention. Baseline BMI was positively associated with weight reduction during the intervention, whereas baseline leptin had only a minor predictive value.

Long-term effects of an inpatient weight-loss program in obese children and the role of genetic predisposition-rationale and design of the LOGIC-trial

Background

The prevalence of childhood obesity has increased worldwide, which is a serious concern as obesity is associated with many negative immediate and long-term health consequences. Therefore, the treatment of overweight and obesity in children and adolescents is strongly recommended. Inpatient weight-loss programs have shown to be effective particularly regarding short-term weight-loss, whilst little is known both on the long-term effects of this treatment and the determinants of successful weight-loss and subsequent weight maintenance.

The purpose of this study is to evaluate the short, middle and long-term effects of an inpatient weight-loss program for children and adolescents and to investigate the likely determinants of weight changes, whereby the primary focus lies on the potential role of differences in polymorphisms of adiposity-relevant genes.

Methods/Design

The study involves overweight and obese children and adolescents aged 6 to 19 years, who participate in an inpatient weight-loss program for 4 to 6 weeks. It started in 2006 and it is planned to include 1,500 participants by 2013. The intervention focuses on diet, physical activity and behavior therapy. Measurements are taken at the start and the end of the intervention and comprise blood analyses (DNA, lipid and glucose metabolism, adipokines and inflammatory markers), anthropometry (body weight, height and waist circumference), blood pressure, pubertal stage, and exercise capacity. Physical activity, dietary habits, quality of life, and family background are assessed by questionnaires. Follow-up assessments are performed 6 months, 1, 2, 5 and 10 years after the intervention: Children will complete the same questionnaires at all time points and visit their general practitioner for examination of anthropometric parameters, blood pressure and assessment of pubertal stage. At the 5 and 10 year follow-ups, blood parameters and exercise capacity will be additionally measured.

Discussion

Apart from illustrating the short, middle and long-term effects of an inpatient weight-loss program, this study will contribute to a better understanding of inter-individual differences in the regulation of body weight, taking into account the role of genetic predisposition and lifestyle factors.

Trial Registration

NCT01067157.

Association of a MTNR1B gene variant with fasting glucose and HOMA-B in children and adolescents with high BMI-SDS

CONTEXT

Genome-wide association studies have shown that the melatonin receptor 1B (MTNR1B) gene locus is strongly associated with fasting glucose and β-cell function. However, data are rather limited to the adult population and normal-weight children. So far, little is known whether similar associations are present in overweight and obese children and adolescents.

OBJECTIVE

The aim is to investigate an MTNR1B polymorphism in a sample of 310 overweight and obese children and adolescents (mean body mass index standard deviation score (BMI-SDS)): 2.74 (± 0.55), mean age: 14 (± 2) years), who participated in a short-term weight-loss program based on energy reduction, physical activity, and behavior therapy.

METHODS

We investigated an association between genotype and fasting glucose, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and of β-cell function (HOMA-B), and anthropometric parameters and their change during intervention.

RESULTS

The minor G allele of polymorphism rs10830963 was significantly associated with increased fasting glucose (0.205  mmol/l, P<0.0001) and decreased HOMA-B (-0.353, P < 0.0001). Categorizing the sample into BMI-SDS groups, these significant associations were abolished in children with BMI-SDS below 2.5 but remained in those with higher BMI-SDS values with stronger β-estimates. The P value for the genotype × BMI-SDS category interaction was 0.012 for fasting glucose and 0.083 for HOMA-B. There was no significant association between genotype and anthropometric parameters and their change during intervention.

CONCLUSIONS

This is the first single study, replicating the association between the MTNR1B locus and diabetes-related traits in overweight and obese children and adolescents. The effect sizes in children and adolescents seem to be stronger than in adults and differed among BMI-SDS categories.

The asthma six-minute provocation test and mountain climbing in children

We investigated the intensity of exercise in the asthma six-minute provocation test (ASMT) for asthmatic patients and mountain climbing. Six asthmatic boys with mean age 11.7 +/- 2.1 years and mean weight 44.5 +/- 13.2 kg participated in this study. HR, FEV1 and RR values were recorded. In both forms of exercise, the participants achieved intensities of over 160 beats/min. EIA was diagnosed in five of them after the SSMT. There was not much variability in the PEFR values observed during mountain climbing. The rise in systolic pressure was within normal. The echocardiogram (ECG) was not pathologic. Further investigations are required to establish the suitability of mountain climbing as an appropriate form of sport for asthmatics.

The effect of a three week sports training programme on the coordinative ability of asthmatic children

We set out to evaluate the coordinative ability of asthmatic children and to find out how this component of physical fitness is affected by a training programme of a short duration. Seventeen asthmatic children participated in the study. Their ages ranged from 9.0 to 14.5 years. Their mean weight (+/- SD) was 44.89 +/- 14.94 kg and mean height (+/- SD) was 153.21 +/- 9.92 cm. Coordination was measured using the Body Coordination Test for Children (BCTC) developed by Kiphard and Schilling in 1974. The subjects participated three times a week in a sports programme. The results were analysed using the Wilcoxon test for dependent variables and regression analysis. We noted a significant improvement at the end of the training programme (p < 0.05), although there was no correlation between attendance and improvement in performance. Our results do not support the general view that asthmatics are unfit. We concluded that asthmatic children are not generally unfit, and that their coordinative ability can be improved within a relatively short time of training.

[The social background of obese children]

Personal data (family situation, father's profession, working vs non-working mother, type of school) of 129 Bavarian children hospitalised for obesity were compared with data from children of the Bavarian population as a whole. Obese children were overrepresented in the low and in the upper socio-economic class. Pupils in special schools were overrepresented. One-parent families were overrepresented (22% vs 14% in the overall population). There is a high proportion of divorces. The percentage of working mothers corresponds with the percentage of working mothers in the overall population. The awareness of obesity as a disease seems to be class-specific. The results of treatment depend on the attitude of the parents.