Different anthropometric adiposity measures and their association with cardiovascular disease risk factors: a meta-analysis

Objectives

To investigate which anthropometric adiposity measure has the strongest association with cardiovascular disease (CVD) risk factors in Caucasian men and women without a history of CVD.

Design

Systematic review and meta-analysis.

Methods

We searched databases for studies reporting correlations between anthropometric adiposity measures and CVD risk factors in Caucasian subjects without a history of CVD. Body mass index (BMI), waist circumference, waist-to-hip ratio, waist-to-height ratio and body fat percentage were considered the anthropometric adiposity measures. Primary CVD risk factors were: systolic blood pressure, diastolic blood pressure, high density lipoprotein (HDL) cholesterol, triglycerides and fasting glucose. Two independent reviewers performed abstract, full text and data selection.

Results

Twenty articles were included describing 21,618 males and 24,139 females. Waist circumference had the strongest correlation with all CVD risk factors for both men and women, except for HDL and LDL in men. When comparing BMI with waist circumference, the latter showed significantly better correlations to CVD risk factors, except for diastolic blood pressure in women and HDL and total cholesterol in men.

Conclusions

We recommend the use of waist circumference in clinical and research studies above other anthropometric adiposity measures, especially compared with BMI, when evaluating CVD risk factors.

Towards an individualized protocol for workload increments in cardiopulmonary exercise testing in children and adolescents with cystic fibrosis

BACKGROUND

There is no single optimal exercise testing protocol for children and adolescents with cystic fibrosis (CF) that differs widely in age and disease status. The aim of this study was to develop a CF-specific, individualized approach to determine workload increments for a cycle ergometry testing protocol.

METHODS

A total of 409 assessments consisting of maximal exercise data, anthropometric parameters, and lung function measures from 160 children and adolescents with CF were examined. 90% of the database was analyzed with backward linear regression with peak workload (W(peak)) as the dependent variable. Afterwards, we [1] used the remaining 10% of the database (model validation group) to validate the model's capacity to predict W(peak) and [2] validated the protocol's ability to provide a maximal effort within a 10±2 minute time frame in 14 adolescents with CF who were tested using this new protocol (protocol validation group).

RESULTS

No significant differences were seen in W(peak) and predicted W(peak) in the model validation group or in the protocol validation group. Eight of 14 adolescents with CF in the protocol validation group performed a maximal effort, and seven of them terminated the test within the 10±2 minute time frame. Backward linear regression analysis resulted in the following equation: W(peak) (W)=-142.865+2.998×Age (years)-19.206×Sex (0=male; 1=female)+1.328×Height (cm)+23.362×FEV(1) (L) (R=.89; R(2)=.79; SEE=21). Bland-Altman analysis showed no systematic bias between the actual and predicted W(peak).

CONCLUSION

We developed a CF-specific linear regression model to predict peak workload based on standard measures of anthropometry and FEV(1), which could be used to calculate individualized workload increments for a cycle ergometry testing protocol.

Exercise and inflammation in pediatric Crohn's disease

We examined inflammatory cells, cytokines and growth factors in response to acute bouts of moderate intensity continuous exercise and high intensity intermittent exercise in youth with Crohn's disease and in healthy matched-controls. 15 patients and 15 controls performed 30 min of cycling at 50% of peak mechanical power (PMP) and 6 bouts of 4×15-s of cycling at 100% PMP. Blood was collected at rest, at the mid-point, at the end of exercise and at 30 and 60 min into recovery. In patients with CD, both types of exercise increased immune cells and GH and decreased IGF-I. Moderate intensity exercise induced a greater increase in leukocytes (p<0.05), neutrophils (p<0.05), lymphocytes (p<0.001), monocytes (p<0.05), IL-6 (p<0.05), IL-17 (p<0.05) and GH (p<0.05) and a similar decrease in IGF-I, compared with high intensity exercise. TNF-α did not change significantly with either exercise. Responses in patients were similar compared with controls; however, in patients monocytes remained elevated significantly longer in response to MICE. Youth with Crohn's disease can engage in distinctly different types of exercise without a significant acute exacerbation of inflammation.

Factors associated with physical activity in patients with osteoarthritis of the hip or knee: a systematic review

OBJECTIVE

To give an overview of factors related to the level of physical activity in patients with hip or knee osteoarthritis (OA).

METHODS

An extensive systematic literature search was conducted in PubMed, CINAHL and Embase. Inclusion criteria were: studies on patients with a diagnosis of OA of hip and/or knee, studies describing factors related to physical activity (objective or subjective), full length articles that were published in Dutch, German or English language. Two reviewers independently assessed the methodological quality. A best-evidence synthesis was performed for factors which were investigated in two or more studies.

RESULTS

Eight studies were included, all with a cross-sectional design (five high quality and three low quality studies), resulting in, at most, limited evidence in the best-evidence synthesis. For patients with knee OA there is limited evidence that a lower level of physical function is associated with a lower level of physical activity. There is also limited evidence that depression is not associated with the level of physical activity. For patients with hip OA there is limited evidence that higher age, higher body mass index (BMI) and a low level of physical function is associated with a low level of physical activity.

CONCLUSION

A high age (hip OA), a high BMI (hip OA) and a low level of physical function (both hip and knee OA) are related to a low level of physical activity. However, the level of evidence was only limited. Before new strategies and interventions to increase physical activity in patients with OA can be developed, high quality longitudinal studies are needed to get more insight in the causality between factors and low levels of physical activity.

Cardiopulmonary exercise testing in congenital heart disease: equipment and test protocols

Cardiopulmonary exercise testing (CPET) in paediatric cardiology differs in many aspects from the tests as performed in adult cardiology. Children's cardiovascular responses during exercise testing present different characteristics, particularly oxygen uptake, heart rate and blood pressure response, which are essential in interpreting haemodynamic data. Diseases that are associated with myocardial ischaemia are very rare in children. The main indications for CPET in children are evaluation of exercise capacity and the identification of exercise-induced arrhythmias. In this article we will review exercise equipment and test protocols for CPET in children with congenital heart disease. (Neth Heart J 2009;17:339-44.).

Habitual physical activity in Dutch children and adolescents with haemophilia

For patients with haemophilia, a physically active lifestyle is important to maintain musculoskeletal health and to prevent chronic diseases, such as cardiovascular disease. Therefore, we studied physical activity levels, in Dutch children and adolescents with haemophilia as well as its association with aerobic fitness and joint health. Forty-seven boys with haemophilia (aged 8-18) participated. Physical activity was measured using the Modifiable Activity Questionnaire (MAQ) and was compared with the general population. Aerobic fitness was determined using peak oxygen uptake (VO(₂peak)). Joint health was measured using the Haemophilia Joint Health Score (HJHS). Associations between physical activity, joint health and aerobic fitness were evaluated by correlation analysis. Subjects were 12.5 (SD 2.9) years old, had a Body Mass Index (BMI) of 19.5 (SD 3.1; z-score 0.5) and a median HJHS score of 0 (range 0-6). Cycling, physical education and swimming were most frequently reported (86%, 69% and 50% respectively). Children with severe haemophilia participated significantly less in competitive soccer and more in swimming than children with non-severe haemophilia. Physical activity levels were similar across haemophilia severities and comparable to the general population. VO(₂peak) kg⁻¹ was slightly lower than healthy boys (42.9 ± 8.6 vs. 46.9 ± 1.9 mL kg⁻¹ min⁻¹; P = 0.03). Joint health, aerobic fitness and physical activity showed no correlation. Dutch children with haemophilia engaged in a wide range of activities of different intensities and showed comparable levels of physical activity to the general population. Aerobic fitness was well preserved and showed no associations with physical activity levels or joint health.

The oxygen uptake efficiency slope in children with congenital heart disease: construct and group validity

OBJECTIVE

The oxygen uptake efficiency slope (OUES) has been proposed as an independent and objective alternative to the peak oxygen uptake (VO(2peak)), which does not require maximal exercise. The aim of this study was to investigate the construct and group validity of the OUES in children with congenital heart disease (CHD).

METHODS

Thirty-one patients with CHD, of which 16 patients (mean age ± SD 11.2 ± 2.7 years) with a Fontan repair and 15 patients (mean age ± SD 13.2 ± 3.6 years) with surgical repair of tetralogy of Fallot (ToF) completed a symptom-limited cardiopulmonary exercise test. The OUES was calculated and normalized for body surface area at three different exercise intensities: (1) using 100% of the exercise data; (2) using the first 75% of the exercise data; and (3) using exercise data up to the ventilatory threshold (VT). Furthermore, peak oxygen uptake (VO(2peak)), VT, ventilatory efficiency (V(E)/VO(2)-slope), and ventilatory drive (V(E)/VCO(2)-slope) were calculated and compared with values of 46 healthy children (mean age ± SD 12.2 ± 2.4 years).

RESULTS

In all three groups, the OUES values determined at the three different exercise intensities were not significantly different from each other. Moreover, the OUES was significantly reduced in the children with CHD, with significantly lower values in the Fontan patients compared to ToF. Strong correlations were found between the OUES and both the VO(2peak) and VT in Fontan and ToF patients.

DISCUSSION

The OUES provides a valid measure of cardiopulmonary fitness in children with CHD, which is independent of exercise intensity and strongly correlated with VO(2peak) and VT (construct validity). Furthermore, the OUES is capable of differentiating between healthy children and children with CHD and between Fontan and ToF patients (group validity). Therefore, the OUES may be a valid, effort-independent parameter of cardiopulmonary fitness in children with CHD.

Is static hyperinflation a limiting factor during exercise in adolescents with cystic fibrosis?

Increased work of breathing is considered to be a limiting factor in patients with cystic fibrosis (CF) performing aerobic exercise. We hypothesized that adolescents with CF and with static hyperinflation are more prone to a ventilatorily limited exercise capacity than non-static hyperinflated adolescents with CF. Exercise data of 119 adolescents with CF [range 12-18 years], stratified for static hyperinflation, defined as ratio of residual volume to total lung capacity (RV/TLC) > 30%, were obtained during a progressive bicycle ergometer test with gas analysis and analyzed for ventilatory limitation. Static hyperinflation showed a significant, though weak association (Φ 0.38; P < 0.001) with a ventilatorily limited exercise capacity (breathing reserve index at maximal effort >0.70; FEV(1)  < 80% predicted and reduced exercise capacity, defined as VO(2peak)  < 85% predicted). Analysis of association for increasing degrees of hyperinflation showed an increase to Φ 0.49 (P < 0.001) for RV/TLC > 50%. In adolescents with static hyperinflation, peak work rate (W(peak) ; 3.1 ± 0.7 W/kg (75.1 ± 17.3% of predicted), peak oxygen uptake (VO(2peak) /kg (ml/min/kg); 39.2 ± 9.2 ml/min/kg (91.0 ± 20.3% of predicted), peak heart rate (HR(peak) ; 176 ± 19 beats/min) were significantly (P < 0.05) decreased when compared with non-static hyperinflated adolescents (W(peak) 3.5 ± 0.5 W/kg (81.4 ± 10.0% of predicted)); VO(2peak) /kg (ml/min/kg); 43.1 ± 7.5 ml/min/kg (98.0 ± 15.1% of predicted); and HR(peak) 185 ± 14 beats/min). Additionally, no difference was found in the degree of association of FEV(1) (%) and RV/TLC (%) with VO(2peak) /kg(pred) and W(peak) /kg(Pred) , but we found the RV/TLC (%) to be a slightly stronger predictor of VO(2peak) /kg(pred) and W(peak) /kg(Pred) than FEV(1) (%). These results indicate that the presence of static hyperinflation in adolescents with CF by itself does not strongly influence ventilatory constraints during exercise and that static hyperinflation is only a slightly stronger predictor of W(peak) /kg(Pred) and VO(2peak) /kg(Pred) than airflow obstruction (FEV(1) (%)).

High-intensity interval training in an adolescent with cystic fibrosis: a physiological perspective

Nutritional, musculoskeletal, and/or ventilatory status can lead to a decreased exercise capacity in children with cystic fibrosis (CF). Exercise training is already part of the usual care; however, the "optimal" intensity and volume of exercise training to improve exercise capacity is still unknown. Six weeks of high-intensity interval training (HIT) for a patient with CF with a ventilatory limitation was evaluated by a cardiopulmonary exercise test (CPET). Peak oxygen uptake and peak workload increased 19% and 16%, respectively, and there was a rise in peak ventilation from 50 L/min to 75 L/min, with an increase in both breathing depth and respiratory rate. A relative short period of HIT resulted in a significant increase in exercise capacity. In patients with CF, HIT might be an effective and efficient training regimen, especially in CF patients with a ventilatory limitation. Further research is necessary to investigate whether HIT is a better alternative than traditional aerobic training programs especially in ventilatory limited patients with CF.

Aerobic capacity and muscle strength in juvenile-onset mixed connective tissue disease (MCTD)

OBJECTIVES

To study the aerobic capacity and muscle strength in children and adolescents with mixed connective tissue disease (MCTD). Frequently reported clinical symptoms include joint swelling, muscle weakness, fatigue, decreased stamina/exercise tolerance, and shortness of breath. The exercise capacity of patients with MCTD has not been studied systematically in this detail before.

METHODS

Eleven children and adolescents diagnosed with MCTD (mean age 15.7 years, range 11.3–19.9 years) were studied. Maximal exercise testing on a cycle ergometer was used to determine the peak oxygen uptake (VO2peak) and a hand-held dynamometer was used to measure muscle strength. Cardiac and pulmonary function tests (ultrasonography, electrocardiography, spirometry) were used to measure cardiac function and obstructive or restrictive respiratory impairment. Complementary data (e.g. disease duration and concurrent symptoms) were collected from a medical chart review.

RESULTS

VO2peak was significantly lower in patients with MCTD compared to the VO2peak of healthy subjects (Z-score –1.9, p = 0.008). The strength of the proximal muscles (hip flexors, shoulder abductors, knee extensors) of the patients was significantly lower than in the controls, whereas the strength of the distal muscles (dorsal flexors of the foot and handgrip strength) showed no differences. In eight children, arthritis was observed. No clinically relevant impairment in cardiac or pulmonary function was observed.

CONCLUSIONS

Aerobic capacity and also proximal muscle strength were significantly impaired in our sample of children and adolescents with MCTD. Because respiratory problems were non-dominant in our patient group, the decreased aerobic capacity and muscle strength were probably caused by musculoskeletal impairments. Further studies in larger multicentre samples are warranted to confirm our findings.

The Dutch translation of the revised Childhood Health Assessment Questionnaire: a preliminary study of score distribution

BACKGROUND

The Childhood Health Assessment Questionnaire (CHAQ30) is the most commonly used physical functioning questionnaire for children with Juvenile Idiopathic Arthritis (JIA). By revising the CHAQ30 Lam et al. succeeded in decreasing the ceiling effect of this questionnaire in a North American population of children with diverse musculoskeletal diseases.

OBJECTIVES

To examine the score distribution of the revised CHAQ in a population of children with JIA.

METHODS

In this Dutch multicentre study 72 children with JIA participated (55 girls), with a mean age of 11.0 (+/- 3.1) and a mean disease duration of 4.6 year (+/- 3.7). The score distribution of the original CHAQ30 and four versions of the revised CHAQ was analysed with the median, range and interquartile range (IQR) and visualised with box-and-whisker plots. The normality of the score distribution was tested by the Kolmogorov-Smirnov one-sample test of normality.

RESULTS

Although the addition of 8 more challenging items improved the spread of the scores of the revised CHAQ versions, the original CHAQ30 showed a better distribution of the scores.

CONCLUSIONS

The revised CHAQ38 with the distribution characteristics, found in this study, might be especially relevant in interventions for patients with JIA at the mild end of the disability spectrum.

Reproducibility of energy cost of locomotion in ambulatory children with spina bifida

OBJECTIVES

Many ambulatory children with Spina Bifida (SB) experience functional decline in ambulation despite stable or even improving motor exams. Improving or maintaining low energy cost of locomotion during childhood and throughout the teenage years, could be an important goal for children and adolescents with SB. Purpose of this study was to determine reproducibility of energy expenditure measures during gait in ambulatory children with SB.

DESIGN

Reproducibility study.

SETTING

Child Development and Exercise Center of the University Children's Hospital in Utrecht, the Netherlands.

PARTICIPANTS

Fourteen ambulatory children (6 boys/8 girls) with SB. Mean age was 10.8 years (+ or - 3.4).

INTERVENTIONS

Net and gross energy expenditure measures during locomotion were determined during a six-minute walking test. These measures consisted of energy consumption (ECS), expressed in J/kg/min, and energy cost (EC), expressed in J/kg/m. For reliability, the intra-class coefficient (ICC) was determined. For agreement, the smallest detectable difference (SDD) was calculated.

RESULTS

ICCs vary from 0.86 to 0.96 for both EC and ECS. The SDD ranges from 18-24% for gross measures, up to over 30% for net values.

CONCLUSION

Reproducibility of energy expenditure during ambulation in children with SB should be considered carefully when using these measures in the evaluation of gait. High reliability of energy expenditure measurements makes these measurements appropriate to use as discriminative tools in children with SB, while agreement of only gross EC seems acceptable to use as a evaluative tool in children with SB. Overall, measures of reliability and agreement seem higher in young children when compared to adolescents. Further research is recommended to determine clinically relevant changes in energy expenditure in children with SB.

Workload demand in police officers during mountain bike patrols

To the authors' knowledge this is the first paper that has used the training impulse (TRIMP) 'methodology' to calculate workload demand. It is believed that this is a promising method to calculate workload in a range of professions in order to understand the relationship between work demands and aerobic fitness. The aim of this study was to assess workload demand in police officers from the Utrecht police department in the Netherlands, during patrol by mountain bike. Maximum oxygen intake, maximum heart rate (HRmax), ventilatory threshold (VT)1 and VT2 were determined with a maximal exercise test on a bicycle ergometer. Heart rates were registered throughout three shifts in 20 subjects using a heart rate monitor. Exercise intensity was divided into three phases: phase I (between 40% of HRmax and VT1); phase II (between VT and the respiratory compensation point (RCP)); and phase III (>RCP). The total TRIMP score was obtained by summating the results of the three phases. Average daily workload demands of 355 TRIMPs per day and 1777 TRIMPs per week were measured. Workload demand approached and in some cases exceeded the upper limit of 2000 TRIMPs per week threshold level for physiological stress demands in professional male cyclists.

Exercise therapy in juvenile idiopathic arthritis: a Cochrane Review

BACKGROUND

Exercise therapy is considered an important component of the treatment of arthritis. The efficacy of exercise therapy has been reviewed in adults with rheumatoid arthritis but not in children with juvenile idiopathic arthritis (JIA).

OBJECTIVES

To assess the effects of exercise therapy on functional ability, quality of life and aerobic capacity in children with JIA.

METHODS

Several electronic databases were searched up to October 2007 and references were tracked. The selection criteria were randomized controlled trials (RCTs) of exercise treatment in JIA. As for data collection and analysis, potentially relevant references were evaluated and all data were extracted by two review authors working independently.

RESULTS

Three out of 16 identified studies met the inclusion criteria, with a total of 212 participants. All the included studies fulfilled at least seven of 10 methodological criteria. The outcome data of the following measures were homogenous and were pooled in a meta-analysis: functional ability (N=198; weighted mean difference [WMD] -0.07, 95% CI -0.22 to 0.08), quality of life (CHQ-PhS: N=115; WMD -3.96, 95% CI -8.91 to 1.00) and aerobic capacity (N=124; WMD 0.04, 95% CI -0.11 to 0.19). The results suggest that the outcome measures all favoured the exercise therapy but none were statistically significant. None of the studies reported negative effects of the exercise therapy.

CONCLUSIONS

Overall, based on ''silver-level'' evidence there was no clinically important or statistically significant evidence that exercise therapy can improve functional ability, quality of life, aerobic capacity or pain. The included and excluded studies were all consistent about the adverse effects of exercise therapy; no short-term detrimental effects of exercise therapy were found in any study. Both included and excluded studies showed that exercise does not exacerbate arthritis. Although the short-term effects look promising, the long-term effect of exercise therapy remains unclear.