Body mass index and physical fitness in Brazilian adolescents

ObjectiveEvaluate the relationship between body mass index and physical fitness in a cross-sectional sample of Brazilian youth.MethodsParticipants were 3849 adolescents (2027 girls) aged 10–17 years. Weight and height were measured; body mass index was calculated. Physical fitness was evaluated with a multistage 20 m shuttle run (cardiovascular endurance), standing long jump (power), and push-ups (upper body strength). Participants were grouped by sex into four age groups: 10–11, 12–13, 14–15, and 16–17 years. Sex-specific ANOVA was used to evaluate differences in each physical fitness item among weight status categories by age group. Relationships between body mass index and each physical fitness item were evaluated with quadratic regression models by age group within each sex.ResultsThe physical fitness of thin and normal youth was, with few exceptions, significantly better than the physical fitness of overweight and obese youth in each age group by sex. On the other hand, physical fitness performances did not consistently differ, on average, between thin and normal weight and between overweight and obese youths. Results of the quadratic regressions indicated a curvilinear (parabolic) relationship between body mass index and each physical fitness item in most age groups. Better performances were attained by adolescents in the mid-range of the body mass index distribution, while performances of youth at the low and high ends of the body mass index distribution were lower.ConclusionRelationships between the body mass index and physical fitness were generally nonlinear (parabolic) in youth 10–17 years.     

Moderately elevated body mass index is associated with metabolic variables and cardiovascular risk factors in Swedish children

Aim: To evaluate associations between anthropometrics and metabolic variables as well as cardiovascular risk factors among children. Methods: Subjects were recruited from a cohort of 274 healthy children in Umeå, Sweden. Anthropometric measures, blood pressure and venous blood samples were collected at age 10 years and simultaneously from parents. Results: Altogether 144 children (53%), 142 mothers and 123 fathers participated. The prevalence of overweight and obesity among the children was 18 and 2%, respectively. Overweight children (above age‐ and sex‐specific cut offs corresponding adult BMI ≥ 25 kg/m²), compared to normal weight children, had significantly higher BMI already during infancy and higher S‐insulin and Homeostatic Model Assessment (HOMA) index at 10 years. The children’s BMI was positively associated with waist (boys’ r = 0.67, girls’ r = 0.81), hip (r = 0.68), waist/hip ratio (girls’ r = 0.37), waist/height ratio (boys’ r = 0.59, girls’ r = 0.80), sagittal abdominal diameter (r = 0.75), S‐insulin (r = 0.45), HOMA index (r = 0.49), systolic blood pressure (r = 0.24), mothers’ BMI (girls’ r = 0.42) and mothers’ waist (girls’ r = 0.42). Conclusion: Children at 10 years of age with moderately elevated BMI had higher levels of some metabolic variables and cardiovascular risk factors than did normal weight children, and there was a correlation between BMI and some metabolic variables as well as cardiovascular risk factors.     

A 3-year longitudinal analysis of changes in fitness, physical activity, fatness and screen time

Aim:  To analyse whether changes in physical activity index (PAI), screen time (ST: television, computer) and body mass index (BMI) made a contribution to longitudinal changes in fitness of children and adolescents. Additionally, we analysed the interaction between baseline fitness level and changes in fitness.
Methods:  This is a 3-year longitudinal study of 345 high school students aged 11–19 years. Students performed curl-ups, push-ups and 20-m shuttle run tests from Fitnessgram. PA and ST were evaluated using a standard questionnaire. Standardized scores of fitness tests were summed. Changes over time were calculated as Δ₁ (2007 minus 2006), Δ₂ (2008 minus 2007) and Δ₃ (2008 minus 2006).
Results:  Changes in PAI were positively and independently associated with changes in fitness in Δ₁, Δ₂ and Δ₃. Changes in BMI were negatively associated with changes in fitness in Δ₃. Participants highly fit at baseline were those who showed positive changes in PAI over Δ₃, decreased changes in ST and had the lowest increase in BMI over 3 years compared with those low-fit at baseline.
Conclusions:  Changes in BMI were associated with changes in fitness over 3 years. However, changes in PAI were the best predictor for changes in fitness in each year and over the 3 years of evaluation in youth.     

Physical activity and aerobic fitness in children after liver transplantation

To determine physical activity (PA), aerobic fitness, muscle strength, health‐related quality of life (HRQOL), fatigue, and participation in children after liver transplantation. Children, 6‐12 years, at least one year after liver transplantation, participated in this cross‐sectional study. Measurements: Time spent in moderate to vigorous PA (MVPA) was measured using an accelerometer, and aerobic fitness (VO_{2 peak}) was measured by cardiopulmonary exercise testing. Muscle strength was measured by hand‐held dynamometry. Fatigue was measured using the multidimensional fatigue scale, and HRQOL with the Pediatric Quality of life Core scales and leisure activities was measured using the Children's Assessment of Participation and Enjoyment. Outcomes (medians and interquartile range (IQR)) were compared to norm values. Twenty‐six children participated in this study (14 boys, age 9.7 years, IQR 7.7;11.4). Children spent 0.8 hours/d (IQR 0.6;1.1) on MVPA. One child met the recommendation of at least 1 hour of MVPA every day of the week. Aerobic fitness was similar to norms (VO_{2 peak} 1.4 _L/min, IQR 1.1;1.7, Z‐score ?0.3). Z‐scores of muscle strength ranged between ?1.4 and ?0.4 and HRQOL and fatigue between ?2.3 and ?0.4. Participation was similar to published norms (Z‐scores between ?0.6 and 0.6). Young children after liver transplantation have similar MVPA patterns and aerobic fitness compared to published norms. Despite lower HRQOL, more fatigue, and less muscle strength, these children have similar participation in daily activities. Although children do well, it remains important to stimulate PA in children after liver transplantation in the context of long‐term management.     

Lack of association between television viewing, soft drinks, physical activity and body mass index in children

OBJECTIVE: To examine the cross-sectional and longitudinal associations of physical activity, screen time and dietary habits on the body mass index (BMI) of children. METHODS: A cohort of 122 girls and 146 boys (age at entry 10 years) from three rural states in the western USA was studied over an 18-month period. Subjects were measured for height and weight. Habitual physical activity, screen time (television viewing, video games and computer use) and dietary variables were assessed by a questionnaire. Cross-sectional and longitudinal analyses were conducted to examine the associations between physical activity, screen time and diet with BMI at baseline and follow-up and change in BMI. RESULTS: At baseline, approximately 10% of boys and girls were obese and 17.8% of boys and 14.8% of girls were overweight. BMI showed a high degree of stability for boys and girls (r = 0.90), whereas physical activity, screen time and dietary habits showed moderate stability (r = 0.31-0.50) across the 18-month period. Cross-sectional and longitudinal correlations between physical activity, screen time, diet and BMI were low and non-significant (r < 0.15). The regression models explained between 8% and 22% of the variance in the change in BMI; however, none of the predictor variables were statistically significant. CONCLUSION: Physical activity, screen time and dietary habits were not significantly related to the BMI in cross-sectional or longitudinal analyses. Further research is warranted to better understand the complex, multifactorial phenotype of the BMI in growing and maturing children.     

Overweight,central obesity,and cardiometabolic risk factors in pediatric liver transplantation

PTMS describes the presence of ≥3 cardiometabolic risk factors that include obesity, hypertension, dyslipidemia, and IR. The prevalence of the clustering of ≥3 cardiometabolic risk factors or central obesity has not been studied in pediatric LT recipients. Single‐center, cross‐sectional study. Inclusion criteria: LT recipients 2–18 yr‐old, at least one yr post‐LT. Exclusion criteria: recipients of liver retransplants or multivisceral transplants. Eighty‐seven patients were identified. Median age was 9.8 yr (range 2–18), median time since LT was 6.9 yr (range 1–17). The most common indication for LT was biliary atresia (56%), and the most frequently used immunosuppressant was tacrolimus (80%). The prevalence of overweight and obesity was 21% and 5%, respectively. Central obesity affected 14%, hypertension 44%, IR 27%, low HDL 20%, and hypertriglyceridemia 39% of patients. The prevalence of ≥3 cardiometabolic risk factors was 19%. Fifty percent of the overweight/obese patients had ≥3 risk factors. Time since transplant, immunosuppression and renal function were not different between those with <3 or ≥3 risk factors. Clustering of cardiometabolic risk factors is prevalent in pediatric LT recipients, suggesting an increased risk of future CV events.     

肥胖儿童非酒精性脂肪肝病及代谢综合征发病情况分析

目的 研究肥胖儿童中非酒精性脂肪肝病(NAFLD)与代谢综合征(MS)的发生情况,并探索两者之间的关系.方法 对308例在本院内分泌科住院的9～14岁肥胖儿童进行腰围、体块指数、血脂、肝功能、肝脏B超、糖耐量试验及胰岛素释放试验等各项检查,根据诊断标准分别计算发生NAFLD[包括单纯性非酒精性脂肪肝(SNAFL)、非酒精性脂肪肝炎(NASH)]和MS的患病率,并将308例肥胖患儿分为无肝脏损害的肥胖儿童组(OCWLD组),SNAFL组和NASH组,比较各组胰岛素、胰岛素抵抗(IR)指标及MS的发病率和MS组成成分的发病率.结果 (1)308例中发生NAFLD的达到203例(65.9%),其中发生SNAFL者140例(45.5%),发生NASH者63例(20.5%).(2)308例中发生MS 76例(24.7%),这76例中合并有NAFLD的64例(84.2%).NAFLD组中MS 64例(31.5%),高于OCWLD组的12例(11.4%),差异有统计学意义,但SNAFL组中MS 41例(29.3%),与NASH组的23例(36.5%)比较差异无统计学意义.(3)就单个MS的组成成分来说,OCWLD组与SNALF组比较仅在高血压的发病率上差异有统计学意义,而OCWLD组与NASH组比较在高血压、高血脂、高血糖的发病率上差异均有统计学意义;SNALF组与NASH组比较在高血脂的发病率上差异有统计学意义.随OCWLD向SNAFL和NASH发展,空腹胰岛素水平逐渐上升,IR也越加明显.但NAFLD患儿与MS患儿比较各IR指标差异无统计学意义.结论 肥胖儿童中NAFLD和MS的发生率均已相当高,MS患儿合并NAFLD的比例很高,IR是NAFLD和MS共同的发病基础,且随着NAFLD患儿病情的进展,MS成分指标越来越严重,IR也越来越严重.     

The effect of cardiorespiratory fitness and physical activity levels on cognitive functions in survivors of childhood acute lymphoblastic leukemia

Abstract

Introduction. Most childhood acute lymphoblastic leukemia (ALL) survivors develop chronic treatment-related adverse effects several years after the end of the treatment. Regular physical activity and a good cardiorespiratory fitness can decrease the risks of neurological disturbances and increase cognitive function scores. The aim of this study was to examine the effect of good cardiorespiratory fitness and physical activity levels on cognitive functions.

Methods. We enrolled 219 survivors of childhood ALL. The participants underwent a cardiopulmonary exercise test, neuropsychological tests of executive functions (i.e. verbal fluency, cognitive flexibility, working memory, processing speed) and completed a physical activity questionnaire. We calculated the odds ratio to obtain the preventive fraction of physical activity and cardiorespiratory fitness levels on cognitive functions.

Results. The cohort is 52% male and 48% female. A total of 182 survivors (83%) have a cardiorespiratory fitness below their predicted (<100%). Our analyses show that there is an association between good cardiorespiratory fitness and processing speed (preventive fraction of 70% for dominant hand (p?<?0.01) and 65% for non-dominant hand (p?<?0.01)) and with cognitive flexibility identified as the category switching measure of the D-KEFS verbal fluency (preventive fraction of 61%; p?<?0.05).

Conclusion. Good cardiorespiratory fitness and good levels of physical activity were associated to a preventive fraction for most cognitive function parameters measured. Good cardiorespiratory fitness levels were significantly associated with a lower prevalence of deficits in processing speed (i.e., dominant hand and non-dominant hand) and in cognitive flexibility (i.e., category switching) in childhood acute lymphoblastic leukemia survivors.     

Postoperative exercise training develops normal levels of physical activity in a group of children following cardiac surgery

Summary Children with congenital heart defects often demonstrate a reduced capacity for exercise, even after surgical intervention. Forty subjects, with various heart defects, completed a 5-year study to evaluate the impact of a postoperative training program on their physical exercise capacity.All of the patients were significantly less active than their peers prior to the surgical intervention. Subjects who completed a simple, home exercise program during the first 3 postoperative months achieved a normal level of physical fitness. These benefits were maintained up to 5-years postoperatively without further intervention. Children who did not receive a postoperative training program remained significantly below their healthy peers. Therefore, a simple exercise training program, conducted early in the postoperative period would appear essential to the achievement of appropriate levels of physical activity for children with congenital heart defects.     

烟台市362例学龄前儿童生长发育Z评分与身体素质现状及其相互关系

目的：探讨烟台市学龄前儿童生长发育Z评分、身体素质状况以及Z评分与身体素质间的关系,为儿童保健工作提供科学依据。方法：以2010年国民体质监测烟台地区幼儿组资料中3～4岁儿童362人为研究对象,计算年龄别体重、年龄别身高、年龄别体重指数三项Z评分,及Z评分与身体素质间进行Pearson相关分析。结果：Z评分均值均为正值,低体重、生长迟缓的发生率极低,但肥胖发生率较高（4岁男童高达16.5%）;儿童的身体素质存在年龄和性别差异（P＜0.05）;Z评分与部分身体素质指标间存在一定相关关系（P＜0.05）,但密切程度不高（r值均未超过0.30）。结论：烟台市学龄前儿童生长发育Z评分保持在较高水平;儿童身体素质与年龄和性别有关;Z评分与部分身体素质间有低度相关关系。应采取积极措施调整儿童饮食习惯、加强体育锻炼,预防肥胖、提高身体素质。     

Predictive value of body mass index and waist circumference for metabolic syndrome in 6-12-year-olds

Aim: To determine the predictive value of body mass index (BMI) and waist circumference (WC) and their optimal cut‐off points for metabolic syndrome (MetS), and also the incidence of MetS. Methods: This study included 888 children, aged 6–12 years, who were followed for a mean of 6.6 years. BMI, WC and their optimal cut‐off points to predict MetS were investigated. Results: The cumulative incidence of MetS was 10.7%. The adjusted ORs for age, sex and family history to predict MetS for BMI and WC z‐scores were 2.6 (95% CI, 2.0–3.5) and 2.6 (95% CI, 1.9–3.5), respectively. In their correspondent models, area under the receiver operating characteristic (ROC) curve was 0.73 (95% CI, 0.68–0.79) for BMI z‐scores and 0.72 (95% CI, 0.67–0.78) for WC z‐scores with no statistically significant difference. The optimal cut‐off values for BMI were 16.5 kg/m² for boys and 16.3 kg/m² for girls and those for WC were 57.5 cm for boys and 56.5 cm for girls. Conclusions: Our findings suggest that both BMI and WC have the same power to predict MetS and also children with higher BMI or WC are more susceptible to MetS. Moreover, a high incidence of MetS in children highlights the importance of interventional strategies during early childhood.