Clarice Martins

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.

Association between time spent in sedentary, moderate to vigorous physical activity, body mass index, cardiorespiratory fitness and blood pressure

Background: Elevated blood pressure (BP) has been reported in young people and seems to be associated with body mass index (BMI) and reduced physical activity (PA). Aim: This study sought to analyse the association of BP with BMI, PA intensity patterns and cardiorespiratory fitness (CRF) in youth. Subjects and methods: A cross-sectional study was carried out including 66 boys (13.91±1.76) and 97 girls (14.02±1.71). Anthropometric characteristics, CRF and BP were assessed during school time and accelerometers were utilized to determine intensity of PA. Results: The linear regression model, adjusted for age, sex and height, showed that higher values of BMI were associated (p≤0.05) with higher values of systolic blood pressure (SBP) (1.39; 95% CI: 0.56; 2.23) and diastolic blood pressure (DBP) (1.52; 95% CI: 0.68; 2.37). Additionally, SBP, but not DBP, was inversely associated (p≤0.05) with moderate PA (−0.25; 95% CI: −0.47; −0.02) and positively correlated with sedentary activities (0.04; 95% CI: 0.00; 0.08). Conclusion: The present study showed that BMI and time spent in sedentary activities were inversely associated with SBP. However, time spent in moderate PA was positively associated with SBP. BMI was the single predictor of DBP.

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 childrens and adolescents 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.

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.

Association between Fitness, Different Indicators of Fatness, and Clustered Cardiovascular Diseases Risk Factors in Portuguese Children and Adolescents

Objectives: To investigate the relationship between cardiovascular diseases risk factors, cardiorespiratory fitness and three different indicators of fatness, and investigate if these relationships are independent by each other. Methods: 491 children and adolescents were evaluated. Standardized metabolic risk scores were computed. Multiple linear regression and Univariate Analysis of Variance - GLM were used. Results: Fit youngsters presented a better profile for each of the risk factors. Belonging to the unfit category increased the risk of having high MRS. After adjustments for fatness indicators, the relationship between fitness and MRS disappeared, and obesity indicators presented significant relationship with the MRS.

Inverted BMI rather than BMI is a better predictor of DEXA determined body fatness in children

This study compared body mass index (BMI) and inverted BMI (iBMI) as predictors of body fatness in 177 Portuguese children (149 girls and 96 boys) aged 7–16 years. Participants undertook measures of height and body mass from which BMI (kg/m2) and iBMI (cm2/kg) were determined. Maturation was determined via self-report and fat mass index (FMI, kg/m2) via dual-energy X-ray absorptiometry. Significant relationships were evident between BMI and iBMI and FMI (both P=0.0001). BMI was not normally distributed (P=0.0001) but iBMI was (P>0.05). Analysis of covariance identified that BMI and iBMI, controlling for maturation, were both significant predictors of FMI (both P=0.0001) but that iBMI predicted a slightly greater amount of the variance (adjusted R2=0.970) compared with BMI (adjusted R2=0.968). This study suggests that iBMI is a similar proxy for body fatness compared with BMI in children.

Fitness and metabolic syndrome in obese fatty liver children

Background: Metabolic Syndrome (MS) is highly prevalent among obese children with fatty liver. However, it is well-known that there is a lower prevalence of MS in individuals with higher cardiorespiratory fitness (CRF). Aim: To analyse the association between CRF with features of the MS in obese children that present fat liver indicators, namely abnormal alanine aminotransferase (ALT) values. Methods: A total of 79 obese students (40 girls), 10–11 year-olds ( ± 0.60), with abnormal serum ALT from Porto public schools comprised the sample. Measurements included CRF (20-metre Shuttle Run Test), Metabolic Risk Factors (MRF), according to MS International Diabetes Federation criteria, ALT values (Cholestech LDX® analyser) and maturational stage (Tanner criteria). Logistic regression analysis was used to determine the influence of CRF on MRF adjusted for sex, maturation, and BMI. Results: The logistic regression showed that, despite being classified as being obese and presenting abnormal levels of ALT, those classified as fit were less likely to have MS than their unfit counterparts (OR = 0.52; p ≤ 0.05). Conclusion: Obese-fit children with abnormal ALT values have a significant reduction in the likelihood to be classified as having MS, even after adjustments for gender, maturation and BMI, Thus, CRF might be an important factor for tackling fatty liver among obese.

Cardiorespiratory fitness and TV viewing in relation to metabolic risk factors in Portuguese adolescents

Background: The purpose of this study was to examine whether adolescents who have high levels of cardiorespiratory fitness (CRF) co-existing with low levels of television (TV) viewing present a better metabolic risk profile compared to their low fit and high TV viewing counterparts. Subjects and methods: A total of 372 students (aged 12–15 years old) comprised the sample of this study. Anthropometric data (body mass index and waist circumference) was collected. CRF was calculated based upon the 20 metres shuttle run test. A questionnaire was used to estimate weekly TV viewing. Information about biological maturity and parental education was collected. Participants were then categorized into one of four category profiles according to the scores they achieved: low TV-Fit; high TV-Fit; low TV-Unfit and high TV-Unfit. Metabolic risk score (MRS) was calculated based on the sum of the Z-scores of all the metabolic variables analysed. Results: Logistic regression analyses indicated that the high TV-Unfit group was almost 3-times more likely to be assigned to the high MRS group (OR = 2.85, 95% CI = 1.08–7.50) compared to their low TV-Fit group counterparts. Conclusions: The data showed that the high TV-Unfit group was associated with an increased metabolic risk in adolescents after adjustment for gender, age, biological maturity and parental education.

Exercise intervention and cardiovascular risk factors in obese children. Comparison between obese youngsters taking part in a physical activity school-based programme with and without individualised diet counselling: the ACORDA project.

Abstract Aim: To determine the effects of a school-based exercise intervention programme on cardiovascular risk factors, including body fat (BF), metabolic profile and physical activity (PA) in children with and without individualised dietary counselling approach (IDC and WIDC). Subjects and methods: Forty-six overweight children from 6–16 years old (25 girls, 54.3%; age = 10.3 ± 2.8) of six schools took part in an 8-month interdisciplinary, school-based intervention programme. All children were engaged in PA classes, but only one group was exposed to individualised counselling. Blood pressure (BP), lipids and lipoproteins, accelerometer-based PA, percentage of body fat (%BF) and trunk fat (%TF) measures were taken before and after intervention. General Linear Model (Repeated Measures ANOVA) adjusted for age, maturation and height change was used to analyse the longitudinal effect of individualised counselling between two evaluations in each group. Results: Favourable changes were observed for %BF, %TF, systolic BP and total cholesterol in the IDC group. Subjects WIDC only increased light and moderate–vigorous PA. In IDC, significant effects for time * group interactions were found for systolic BP, total cholesterol and LDL-cholesterol, indicating that counselling might add favourable changes in these markers, beyond those explained by PA and growth. Conclusion: School-based interventions can contribute to counteracting obesity in youth, particularly when individualised dietary counselling is provided. Therefore, the link between schools and professional counselling should be strengthened to ensure consolidated changes towards healthy behaviours.

Effect of a pilot multi-component intervention on motor performance and metabolic risks in overweight/obese youth

ABSTRACT This study evaluated the effect of a multi-component intervention on motor performance (MP) and metabolic risk markers (MRM) in overweight/obese youth. A secondary aim was to examine whether changes in MP are associated to changes in MRM. A 3-month multi-component intervention was performed, consisting of physical exercise sessions (twice/week;1h), nutritional education sessions (once/month), and parental support (twice/week). The sample included 35 volunteers (7–13 y.o), allocated to intervention (INT, n = 17) and control (CONT, n = 18) group. Variables were measured pre (T0) and post intervention (T1). Fasting blood samples were analyzed for MRM. MP tests included the measurement of health related physical fitness components and motor coordination performance (KTK battery). To assess food intake, a 24-hour recall diary was used. GLM-ANCOVA was performed. Standardized scores were calculated for the outcome variables, and multilinear regressions were applied to analyze associations between the key variables. INT group showed improvements in MP, glycolytic and hepatic profiles. After adjustments for MVPA, SB, total intake and maturational stage, negative associations between %ΔMP and %Δglycolytic (β = -.424; 95%CI:-0.343:-0.022), and %Δhepatic scores (β = -.382 95%CI:-0.001:-0.009) were observed. The intervention produced a moderate-to-high effect on the MP and some MRM. Changes in MP were inversely associated with changes in glycolytic and hepatic markers.