Cardiorespiratory fitness associates with metabolic risk independent of central adiposity

This study sought to analyze the associations between cardiorespiratory fitness (CRF), waist circumference (WC) and metabolic risk in children and adolescents. Participants were 633 subjects (58.7% girls) ages 10-18 years. Metabolic risk score (MRS) was calculated from HDL-cholesterol, triglycerides, fasting glucose and mean arterial pressure. MRS was dichotomized into low and high metabolic risk (HMRS). CRF was defined as the maximal oxygen uptake (VO₂max) estimated from the 20 m Shuttle Run Test. The first quartile of CRF was set as the low fitness group. The fourth quartile of WC was defined as high central adiposity. With adjustments for age, sex and WC, CRF was correlated with MRS (r=-0.095; p<0.05). WC was correlated with MRS (r=0.150; p<0.001) after adjustments for age, sex and CRF. Participants who had low fitness levels, presented higher levels of MRS (p<0.001) compared to those who were fit, even after adjustment for age, sex and WC. In comparison with subjects who were fit with normal central adiposity, an increased odds ratio (OR) for being at HMRS was found for participants who were of low fitness level with high central adiposity (OR=2.934; 95%CI= 1.690-5.092) and for those who were of low fitness with normal central adiposity (OR=2.234; 95%CI=1.116-4.279). Results suggest that CRF relates to MRS independently of central adiposity.

Milk intake is inversely related to body mass index and body fat in girls

Dairy foods comprise a range of products with varying nutritional content. The intake of dairy products (DPs) has been shown to have beneficial effects on body weight and body fat. This study aimed to examine the independent association between DP intake, body mass index (BMI), and percentage body fat (%BF) in adolescents. A cross-sectional, school-based study was conducted with 1,001 adolescents (418 boys), ages 15-18 years, from the Azorean Archipelago, Portugal. Anthropometric measurements were recorded (weight and height), and %BF was assessed using bioelectric impedance analysis. Adolescent food intake was measured using a self-administered, semiquantitative food frequency questionnaire. Data were analyzed separately for girls and boys, and separate multiple linear regression analysis was used to estimate the association between total DP, milk, yogurt, and cheese intake, BMI, and %BF, adjusting for potential confounders. For boys and girls, respectively, total DP consumption was 2.6 ± 1.9 and 2.9 ± 2.5 servings/day (P = 0.004), while milk consumption was 1.7 ± 1.4 and 2.0 ± 1.7 servings/day (P = 0.001), yogurt consumption was 0.5 ± 0.6 and 0.4 ± 0.7 servings/day (P = 0.247), and cheese consumption was 0.4 ± 0.6 and 0.5 ± 0.8 servings/day (P = 0.081). After adjusting for age, birth weight, energy intake, protein, total fat, sugar, dietary fiber, total calcium intake, low-energy reporters, parental education, pubertal stage, and physical activity, only milk intake was negatively associated with BMI and %BF in girls (respectively, girls: β = -0.167, P = 0.013; boys: β = -0.019, P = 0.824 and girls: β = -0.143, P = 0.030; boys: β = -0.051, P = 0.548).

CONCLUSION

We found an inverse association between milk intake and both BMI and %BF only in girls.

Association of leisure time physical activity and sports competition activities with high blood pressure levels: study carried out in a sample of Portuguese children and adolescents

BACKGROUND

A better understanding of the different domains and characteristics of children's and adolescent's physical activity (PA) could be a strategy to clarify the association of this behaviour with the early development of cardiovascular risk factors.

OBJECTIVES

To examine the relationship between leisure time physical activity (LTPA) and sports competition activities (SCA) with high blood pressure (HBP) levels in a sample of children and adolescents from Porto, Portugal.

STUDY DESIGN

This is a cross-sectional study, which comprised 503 boys and 572 girls, aged 8-17 years old. LTPA and SCA were assed by self-reported. Students were assigned as active and non-active in SCA or LTPA according to their self-reported participation. Participants were classified as HBP when they are above of the last quartile for systolic and/or diastolic BP adjusted for gender and age.

RESULTS

Do not be engaged in LTPA (OR: 1.47; 95% CI: 1.12; 1.93) and SCA (OR: 1.36; 95% CI: 1.02; 1.81) was significantly associated with the likelihood of being HBP. However, when cardiorespiratory fitness (CRF) (OR: 1.23; 95% CI: 0.91; 1.67) and body mass index (BMI) (OR: 1.31; 95% CI: 0.98; 1.75) were included on SCA model, the association between SCA with HBP did not showed significant results.

CONCLUSION

Children and adolescents who are not engaged in SCA or LTPA are more likely to be classified as having HBP; however, the relationship between SCA and HBP was dependent of CRF and BMI. Further, PA strategies should take these differences on the relationship between HBP, SCA and LTPA.

Accuracy of Siri and Brozek equations in the percent body fat estimation in older adults

OBJECTIVE

To identify which equation, Siri or Brozek, based on the two compartment model, provides a more accurate conversion of body density (BD) in percent body fat (%BF) in a group of older adults.

STUDY DESIGN

Cross-sectional study.

SETTING

Research Centre in Physical Activity, Health and Leisure, Faculty of Sport, University of Porto.

PARTICIPANTS

60 older adults, aged 60-92 years.

MEASUREMENTS

Skinfold thickness was used to estimate BD through Visser et al. prediction equation. The conversion of BD to %BF was done with Siri (%BF-Siri) and Brozek (%BF-Brozek) formulas and these determined values were both compared to Dual-Energy X-ray Absorptiometry (%BF-DXA) evaluations.

RESULTS

A strong correlation between the %BF-DXA value and %BF-Siri (r=0.91, p < 0.001) and %BF-Brozek (r=0.91, p < 0.001) was found, although %BF-Siri and %BF-Brozek overestimated %BF-DXA (p < 0.001). The comparison of the %BF-Siri and %BF-Brozek mean values also revealed significant differences (p < 0.001). The %BF-Brozek reflects a better agreement than the %BF-Siri with %BF-DXA with respectively a mean difference of -4.0 %BF (limits of agreement = -10.9 to 2.9%) and -5.7 %BF (-12.6 to 1.2). The Bland and Altman plots confirmed that %BF-Brozek reflects a better agreement with %BF-DXA.

CONCLUSION

The results of the present study show that the use of Brozek equation may correspond to a more accurate alternative than Siri equation for the conversion of BD in %BF in older adults.

High levels of C-reactive protein are associated with reduced vagal modulation and low physical activity in young adults

The purpose of this study was to examine the relationship between cardiac autonomic control derived from heart rate variability (HRV), high-sensitivity C-reactive protein (hs-CRP) and physical activity (PA) levels measured using accelerometers. A total of 80 healthy university students volunteered to participate in this study (20.56 ± 0.82 years, 1.36 ± 1.5 mg/L of hs-CRP). The participants were divided into groups based on tertiles of hs-CRP. Analysis of covariance adjusted to PA was used to assess group differences in HRV. Associations between hs-CRP, HRV indices and PA were analyzed using Pearson's correlation. The participants at the highest tertile of hs-CRP (tertile 3) had lower cardiac vagal modulation (SDNN, tertile 1=78.05 ± 5.9,tertile 2=82.43 ± 5.9,tertile 3=56.03 ± 6.1; SD1, tertile 1=61.27 ± 5.3, tertile 2=62.93 ± 5.4, tertile 3=40.03 ± 5.5). In addition, vagal indices were inversely correlated with hs-CRP but positively correlated with PA (SDNN r=-0.320, SD1 r=-0.377; SDNN r=0.304, SD1 r=0.299; P<0.05). Furthermore, the most physically active subjects had lower levels of hs-CRP and the highest levels of vagal modulation.

Concurrent validation of estimated activity energy expenditure using a 3-day diary and accelerometry in adolescents

Estimates of daily energy expenditure are important to studies of physical activity and energy balance. Objective measures are not always feasible and further research is needed to validate survey instruments and diaries. The study validates estimated activity energy expenditure (AEE) based on a 3-day diary protocol relative to AEE derived from uniaxial accelerometry in adolescents, 265 girls and 227 boys (12.5-16.4 years). Participants completed the diary and wore a GT1M Actigraph accelerometer on the same days. Height and weight were measured. Correlations between protocols were significant (P<0.001) but moderate, r=0.65 in males and r=0.69 in females. The highest correlation occurred among males on Friday, r=0.74 (P<0.01). Controlling for body mass, partial correlations between protocols decreased to 0.44 and 0.35 in males and females, respectively. About 97% of the cases fell within the limits of agreement in a Bland-Altman plot. The criterion of inclusion for the accelerometer excluded 18% of the initial sample. In summary, the 3-day diary was completed without any major problems and provided a reasonably valid alternative for assessing AEE. Concordance between methods was slightly lower for individuals with higher values of AEE.

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 Delta(1) (2007 minus 2006), Delta(2) (2008 minus 2007) and Delta(3) (2008 minus 2006).

RESULTS

Changes in PAI were positively and independently associated with changes in fitness in Delta(1), Delta(2) and Delta(3). Changes in BMI were negatively associated with changes in fitness in Delta(3). Participants highly fit at baseline were those who showed positive changes in PAI over Delta(3), 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.

Association between overweight and early sexual maturation in Portuguese boys and girls

OBJECTIVE

The purpose of this study was to examine the relationship between sexual maturation (SM), and the prevalence of overweight among boys and girls.

SUBJECTS AND METHODS

The sample of this cross-sectional study included 819 children and adolescents (382 boys and 437 girls), aged 10-15 years old randomly selected from 30 schools in the Porto region. Anthropometrical measurements (body height, weight and skinfolds thickness) were determined by standard anthropometrical methods. Body mass index (BMI) was calculated from the ratio weight/height(2) (kg/m(2)). The sum of tricipital and subscapular skinfolds (TriSub) was also used. Physicians collected data on Tanner stages during physical examination. Subjects were grouped using the quartiles of the decimal age adjusted for Tanner stages of SM and gender.

RESULTS

The prevalence of overweight was higher in early maturing boys (30.5%) and early maturing girls (32.7%). The late maturers presented a lower prevalence (p < 0.05) of overweight (20.3% boys and 18.3% girls). Logistic regression analysis illustrates that early maturing is associated with an increased risk for overweight or obesity for boys (OR: 1.87 and 95% CI: 0.99-3.50) and girls (OR: 2.14 and 95% CI: 1.12-4.07), when compared with the boys and girls of the fourth quartile (p < 0.05).

CONCLUSIONS

We conclude that there is an association between early SM and the prevalence of overweight in both genders.

Effects of resistance and multicomponent exercise on lipid profiles of older women

OBJECTIVE

The purpose of this study was to compare the effects of two exercise programs of 8 months duration on lipid profiles in older women.

METHODS

In 2006, 77 women from Porto, Portugal, aged 60-79 years were randomly assigned into a multicomponent exercise (ME) program or resistance exercise (RE) program. Before- and after-training, body composition, daily physical activity (DPA), aerobic endurance, plasma concentrations of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG) were assessed. Training was performed twice weekly. The protocol for the ME included aerobic exercise, muscular endurance exercises and activities targeted to improve balance and flexibility. The RE protocol included leg press, leg extensions and curls, double chest raises, lateral raises, overhead press and abdominal exercises.

RESULTS

Significant decreases in TG (-5.1%, p=0.006), and significant increases in HDL-C (9.3%, p<0.001) were observed in the ME group. Following 8 months no significant changes were observed on lipid profile in RE group, although lipid- and lipoprotein-related variables tended to alter favorably. Both regimens resulted in significant improvements on 6-min walk test (6.4%, p=0.001 for ME; and 6.0%, p=0.044 for RE). No significant changes were observed in total DPA and body fat in either group after exercise interventions. No significant correlations were found between body composition, physical activity, aerobic endurance, and lipid profile.

CONCLUSIONS

The data suggested that 8 months of ME may be more effective than RE for inducing favorable changes in plasma lipoprotein and lipid profiles.

Physical training does not increase allergic inflammation in asthmatic children

The effects of a 3-month physical training programme on airway inflammation and clinical outcomes were studied in school-aged children with asthma. Subjects with persistent allergic asthma (aged 12.7+/-3.4 yrs; n = 34) were randomly allocated into training and control groups. Exercise consisted of twice-weekly 50-min sessions for 12 weeks. Inflammation was assessed by levels of exhaled nitric oxide, blood eosinophils, eosinophil cationic protein, C-reactive protein, and total and mite-specific immunoglobulin (Ig)E. Lung volumes and bronchial responsiveness to methacholine were determined. The Paediatric Asthma Quality of Life Questionnaire and Paediatric Asthma Caregiver's Quality of Life Questionnaire were used to evaluate activity restrictions, symptoms and emotional stress. The efficacy of the training was assessed by accelerometry. Following the programme, the exercise group spent twice as much time as the controls undertaking moderate-to-vigorous activities. No differences in changes were seen between groups for asthma outcomes. However, total IgE decreased more in the exercise group, as did mite-specific IgE. Training did not increase inflammation in children with persistent asthma, and may have decreased both total and allergen-specific immunoglobulin E levels. It is concluded that there is no reason to discourage asthmatic children with controlled disease to exercise.

Association of physical fitness and body mass index in youth

AIM

The aim of this study was to establish physical fitness (PF) levels in a school population of 11-18-year-old students and analyse differences according to body mass index (BMI) status in overweight

METHODS

This is a cross-sectional study. The sample comprises 636 children and adolescents (mean age of 14.5+/-1.5 years), 288 boys (45.3%) and girls 347 (54.7%). Six tests from Fitness-gram battery were used as an objective measure of physical fitness. Overweight/ Obesity status was determined using age and sex adjusted cut-off points.

RESULTS

Both girls and boys with obesity performed a significantly reduced number of tests in healthy fitness zone suggesting a decrease of performances in strength and cardiovascular fitness, from normal weight status to overweight and from overweight to obesity. Boys and girls with obesity are likely to be Under HFZ than normal weight.

CONCLUSION

The results suggest that obese and overweight children have low PF level compared to normal weight peers. A large number of children with normal weight were identified as well as unfit. These data also showed that a low BMI level would significantly improve some PF component.

S-MRI score: A simple method for assessing bone marrow involvement in Gaucher disease

Semi quantitative MRI is a very useful procedure for evaluating the bone marrow burden (BMB) in Gaucher disease (GD). Score systems have been applied to obtain a parameter for evaluating the severity of bone disease. Our purpose was to test a simple, reproducible and accurate score to evaluate bone marrow involvement in GD patients. MRI was performed in spine, pelvis and femora at diagnosis in 54 adult GD1 patients, 61.1% of whom were female. Three MRI patterns and punctuation in each location were defined: normal, 0; non-homogeneous infiltration subtypes reticular, 1; mottled, 2; diffuse, 3; and homogeneous infiltration, 4. This score was called Spanish-MRI (S-MRI). Two independent observers applied the S-MRI and bone marrow burden score and compared the differences using the non-parametric Mann-Whitney test. Correlation rank test was calculated. In 46 patients (85.2%), bone involvement was observed. Thirty-nine (72.3%) had their spine affected, 35 (64.8%) pelvis and 33 (61.2%) femora. Fourteen patients had bone infarcts, 14 avascular necrosis, 2 vertebral fractures and 2 bone crises. Correlation analysis between S-MRI and BMB was (r(2)=.675; p=.0001). No evidence of correlation was observed between CT activity and S-MRI nor between CT activity and BMB. We have found a relationship between genotype and bone infiltration according to S-MRI site and complications. S-MRI is a simple method that provides useful information to evaluate bone infiltration and detect silent complications. Our results correlated with the BMB score but offer higher sensitivity, specificity and accuracy for classifying the extent of bone disease.