Insulin sensitivity, VO2max and body composition in severely obese Swedish children and adolescents.

AIM: The aim of this study was to identify relationships between insulin sensitivity (SI), cardiorespiratory fitness and body composition in severely obese Swedish children and adolescents. METHODS: Two hundred and twenty-eight obese children (119 girls, 8-16 years, body mass index (BMI) 23.2-57.0 kg/m(2)) performed a frequently sampled intravenous glucose tolerance test (FSIVGTT), a submaximal bicycle ergometry test and a dual-energy X-ray absorptiometry (DEXA). RESULTS: Mean SI (SD) was 0.38 (0.32) (x10(-5)/min/pM). SI correlated positively with relative body mass (BM) VO(2)max (r = 0.42) (p < 0.001), relative fat-free mass (FFM) VO(2)max (r = 0.36) (p < 0.001) and negatively with body mass index standard deviation score (BMI SDS) (r =-0.22) (p = 0.001). SI did not correlate with percent body fat (r =-0.01) and absolute VO(2)max (r = 0.01). In multiple regression analyses with SI as dependent variable, VO(2)max and body composition, together with gender, age and Tanner stage, explained 20-26% of the variance. CONCLUSION: Relative (BM) VO(2)max and relative (FFM) VO(2)max were stronger predictors of SI than percent body fat in severely obese children and adolescents. The study confirms that cardiorespiratory fitness is of importance for the metabolic syndrome in the studied population. Efforts to improve SI should include physical activity targeting cardiorespiratory fitness also in severely obese children and adolescents.

Six-minute walk test in obese children and adolescents: reproducibility and validity.

BACKGROUND AND PURPOSE: The six-minute walk test (6MWT) is increasingly used in clinical practice. The aims of this study were to determine the reproducibility of the 6MWT in obese children and adolescents, to describe walking capacity in this population and compare the results with values from normal-weight children (known group validity), and, finally, to describe the correlation between distance walked and estimated maximum oxygen uptake (VO(2)max). METHODS: Reproducibility was determined by a test-retest design and known group validity by a comparative design. The 6MWT was first test-retested in 49 obese children (30 boys, 19 girls, 8-16 years, body mass index [BMI] 24.9-52.1 kg?m(-2)). Then, for validation, 250 obese children (126 boys, 124 girls, 8-16 years, BMI 23.2-57 kg/m(2)) and 97 normal-weight children (48 boys, 49 girls, 8-16 years, BMI 13.3-23.2 kg.m(-2)) performed the 6MWT. The obese children also performed a sub-maximal bicycle ergometry test. RESULTS: In the test-retest, the obese children walked 571 m the first test and 57 m the second (p = 0.578). The measurement error (S(w)) was 24 m, coefficient of variation (CV): 4.3% and the intraclass correlation (ICC1:1): 0.84. Repeatability was 68 m, and limits of agreement were +71 and -65 m. In comparison mean (standard deviation), six-minute walk distance (6MWD) in the obese children was 571 m (65.5), and in the normal-weight children, 663 m (61.1) (p < 0.001). The correlation between 6MWD and estimated VO(2)max (r = 0.34) was low. CONCLUSIONS: The 6MWT showed good reproducibility and known group validity, and can be recommended for use in clinical practice in the studied population. To evaluate individual outcomes after intervention, the 6MWD needs to change by >68 m to be statistically significant. The 6MWD performed by obese children averaged 86% of the distance normal-weight children walked. In obese children, the correlation between 6MWD and estimated VO(2)max was low, hence the 6MWT cannot substitute a bicycle ergometry test.

The six-minute walk test in outpatients with obesity: reproducibility and known group validity.

BACKGROUND AND PURPOSE: To assess the reproducibility and validity of the six-minute walk test (6MWT) in men and women with obesity in order to facilitate evaluation of treatment outcome. METHOD: A test--retest design was used to test reproducibility and a comparative design to test known group validity. Forty-three obese outpatients (16 male), mean age 47 (21-62) years, mean body mass index (BMI) 40 (3-62)kg-m(-2) performed the 6MWT twice within one week. Intraclass correlation (ICC1.1) and measurement error (S(w)) were calculated from the mean square values derived from a one-way repeated-measures ANOVA (fixed effect model). The reproducibility was also analysed by means of coefficient of variation (CV) and the Bland Altman method including 95% limits of agreement. The variance of the distance walked was analysed by means of regressions. The known group validity of the 6MWT (distance walked and the work of walking) in obese participants was shown by comparisons with 41 lean participants (18 male), mean age 47 (24-65) years, mean BMI 22.7 kg-m(-2) (19-25). RESULTS: The obese group walked 534 m (confidence interval [CI] 508-560 the first and 552 m (CI 523-580) the second walk (p < 0.001). S(w) was 25 m, CV 4.7%, ICC1.1 was 0.96. The limits of agreement were -46 m+80 m. The validity tests showed that they walked 162 m shorter (p < 0.001) and performed much heavier work (p < 0.001) than the lean group. In the obese group, BMI alone explained 38% of the variance of the distance walked. CONCLUSIONS: The 6MWT showed good reproducibility and known group validity and can be recommended for evaluating walking ability in subjects with obesity. For individual evaluation, however, an improved walking distance of at least 80 m was required to make the difference clinically significant. Despite shorter walking distance the obese participants performed heavier work than the lean.

Influence of weight loss programmes on walking speed and relative oxygen cost (%VO2max) in obese women during walking.

OBJECTIVE: The objective was to investigate effects of dieted weight reduction on walking ability in obese women. METHODS: Fifty-seven obese women 44.1 +/- 10.7 years, body mass index 37.1 +/- 3.4 kg x m(-2) performed an indoor walking test. Speed, oxygen consumption and heart rate were measured, perceived exertion and pain graded and oxygen cost calculated. Maximum oxygen uptake (VO2max/kg) was predicted from a submaximum bicycle ergometry test. All tests were measured at baseline, after 12 weeks' weight reduction and after 52 weeks' maintenance. RESULTS: Despite a partial weight relapse, improvements were seen in body mass index, self-selected walking speed, VO2max/kg, heart rate, perceived exertion and relative oxygen cost of walking (% VO2max). CONCLUSION: A modest weight reduction of 10% in moderately-to-severely obese women significantly improved their walking ability, perceived exertion and %VO2max. When dealing with obese women, attention should be drawn to these positive effects, instead of focusing only on the magnitude of the weight loss.

Inter-examiner reliability of a proposed decision-making treatment based classification system for low back pain patients.

Evolving evidence has shown increased clinical outcomes, when low back pain (LBP) patients are classified and receive matched physical treatment. The present study aimed to examine the inter-examiner reliability of a proposed new decision-making classification system for non-specific LBP patients, using a mixed simultaneous and independent examiner design. With minimal familiarization, two pairs of experienced physiotherapists trained in Orthopedic Manual Therapy (OMT) at two different out-patient clinics in primary care, examined and classified 64 consenting consecutive patients. Further, inter-examiner reliability on five examination items was examined. The agreement between examiners was expressed by percentage of agreement (%) and by the un-weighted (κ) or weighted (κ(w)) kappa coefficient. The overall % agreement, categorizing patients into one of four classifications was 80% and κ = 0.72. For each classification, pain modulation, stabilization exercise, mobilization and training, agreement was 90%, 83%, 58% and 89% (κ = 0.77, 0.67, 0.11 and 0.75), respectively. Agreement on five individual examination items was; irritability 82% (κ(w) = 0.41), specific movement pattern 68% (κ = 0.38), specific segmental signs 67% (κ = 0.28), uni- or bilateral signs 62% (κ = 0.42), and neurological signs and symptoms 92% (κ = 0.84). This study demonstrated that this new classification system had substantial inter-examiner reliability when used by clinically experienced OMT-trained physiotherapists. Agreement within classification was substantial, except for mobilization which was poor. Inter-examiner reliability for the individual examination items varied from fair to almost perfect. Further studies are needed to investigate utility and validity of this new classification system.

Adolescents' perceptions of obesity treatment--an interview study.

PURPOSE: To describe adolescents' perceptions of obesity treatment in order to provide valuable information for design and development of treatment. METHOD: A nominated sample of 18 obese adolescents (12 girls, 14-16 years, body mass index (BMI) 25-47.4 kg·m(-2)), recruited from a paediatric obesity clinic, participated in semi-structured interviews. These were analysed using a phenomenographic research approach. Purposeful sampling reflected variations in age, gender, degree of obesity, weight loss achievement, ethnicity, time of registration and socioeconomic status. RESULTS: The adolescents expressed numerous physical, psychological and social disabilities as a consequence of their obesity. Qualitatively different ways of perceiving and responding to obesity treatment were identified and could be described in six categories of descriptions and a two-dimensional construct for interpreting these categories; (a) personal empowerment, (b) despair and disappointment, (c) safety and relief, (d) ambivalence and uncertainty, (e) acceptance and realisation and (f) shame and guilt. The distinguishing structures to be found between the categories were as follows: focus on the individual and focus on body weight. CONCLUSIONS: Treatment strategies must consider the large impact obesity has on adolescents' lives. It is necessary to engage the obese adolescent personally in the treatment process and to focus on the adolescents' personal needs, goals and motive for weight reduction.