ARTERIAL FUNCTION IN CHILDREN: THE INFLUENCE OF CARDIOVASCULAR FITNESS, PHYSICAL ACTIVITY AND OBESITY

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Linking cardiorespiratory fitness classification criteria to early subclinical atherosclerosis in children

Publication . Melo, Xavier; Santa-Clara, Helena; Santos, Diana; Pimenta, Nuno M.; Minderico, Cláudia S.; Fernhall, Bo; Sardinha, Luís B.

It is unclear if cardiorespiratory fitness (CRF) can be used as a screening tool for premature changes in carotid intima-media thickness (cIMT) in paediatric populations. The purpose of this cross-sectional study was 3-fold: (i) to determine if CRF can be used to screen increased cIMT; (ii) to determine an optimal CRF cut-off to predict increased cIMT; and (iii) to evaluate its ability to predict increased cIMT among children in comparison with existent CRF cut-offs. cIMT was assessed with high-resolution ultrasonography and CRF was determined using a maximal cycle test. Receiver operating characteristic analyses were conducted in boys (n = 211) and girls (n = 202) aged 11-12 years to define the optimal sex-specific CRF cut-off to classify increased cIMT (≥75th percentile). Logistic regression was used to examine the association between the CRF cut-offs with the risk of having an increased cIMT. The optimal CRF cut-offs to predict increased cIMT were 45.81 and 34.46 mL·kg(-1)·min(-1) for boys and girls, respectively. The odds-ratios for having increased cIMT among children who were unfit was up to 2.8 times the odds among those who were fit (95% confidence interval: 1.40-5.53). Considering current CRF cut-offs, only those suggested by Adegboye et al. 2011. (Br. J. Sports Med. 45(9): 722-728) and Boddy et al. 2012 (PLoS One, 7(9): e45755) were significant in predicting increased cIMT. In conclusion, CRF cut-offs (boys: ≤ 45.8; girls: ≤ 34.5 mL·kg(-1)·min(-1)) are associated with thickening of the arterial wall in 11- to 12-year-old children. Low CRF is an important cardiovascular risk factor in children and our data highlight the importance of obtaining an adequate CRF.

2014-12-16Journal article

Open access

Waist-to-Hip Ratio is Related to Body Fat Content and Distribution Regardless of the Waist Circumference Measurement Protocol, in Non-Alcoholic Fatty Liver Disease Patients

Publication . Pimenta, Nuno; Santa-Clara, Helena; Melo, Xavier; Cortez-Pinto, Helena; Silva Nunes, José António; Sardinha, Luis

Central accumulation and distribution of body fat (BF) is an important cardiometabolic risk factor. Waist-to-hip ratio (WHR), commonly elevated in non-alcoholic fatty liver disease (NAFLD) patients, has been endorsed as a risk related marker of central BF content and distribution, but no standardized waist circumference measurement protocol (WCmp) has been proposed. We aimed to investigate whether using different WCmp affects the strength of association between WHR and BF content and distribution in NAFLD patients. BF was assessed with Dual Energy X-ray Absorptiometry (DXA) in 28 NAFLD patients (19 males, 51 ± 13 yrs, and 9 females, 47 ± 13 yrs). Waist circumference (WC) was measured using four different WCmp (WC1: minimal waist; WC2: iliac crest; WC3: mid-distance between iliac crest and lowest rib; WC4: at the umbilicus) and WHR was calculated accordingly (WHR1, WHR2, WHR3 and WHR4, respectively). High WHR was found in up to 84.6% of subjects, depending on the WHR considered. With the exception of WHR1, all WHR correlated well with abdominal BF (r=0.47 for WHR1; r=0.59 for WHR2 and WHR3; r=0.58 for WHR4) and BF distribution (r=0.45 for WHR1; r=0.56 for WHR2 and WHR3; r=0.51 for WHR4), controlling for age, sex and body mass index (BMI). WHR2 and WHR3 diagnosed exactly the same prevalence of high WHR (76.9%). The present study confirms the strong relation between WHR and central BF, regardless of WCmp used, in NAFLD patients. WHR2 and WHR3 seemed preferable for use in clinical practice, interchangeably, for the diagnosis of high WHR in NAFLD patients.

2016-08Journal article

Open access

Waist-to-height ratio is independently related to whole and central body fat, regardless of the waist circumference measurement protocol, in non-alcoholic fatty liver disease patients

Publication . Pimenta, Nuno; Cortez-Pinto, Helena; Melo, Xavier; Silva-Nunes, José; Sardinha, Luís; Santa-Clara, Helena

Background: Waist-to-height ratio (WHtR) has been reported as a prefer-able risk related body fat (BF) marker, although no standardised waistcircumference measurement protocol (WCmp) has been proposed. Thepresent study aimed to investigate whether the use of a different WCmpaffects the strength of relationship between WHtR and both whole andcentral BF in non-alcoholic fatty liver disease (NAFLD) patients.Methods: BF was assessed with dual energy X-ray absorptiometry (DXA) in28 NAFLD patients [19 males, mean (SD) 51 (13) years and nine females,47 (13) years]. All subjects also underwent anthropometric evaluationincluding height and waist circumference (WC) measurement using fourdifferent WCmp (WC1, minimal waist; WC2, iliac crest; WC3, mid-distancebetween iliac crest and lowest rib; WC4, at the umbilicus) and WHtR wascalculated using each WC measurements (WHtR1, WHtR2, WHtR3 andWHtR4, respectively). Partial correlations were conducted to assess the rela-tion of WHtR and DXA assessed BF.Results: All WHtR were particularly correlated with central BF, includingabdominal BF (r = 0.80, r = 0.84, r = 0.84 and r = 0.78, respectively, forWHtR1, WHtR2, WHtR3 and WHtR4) and central abdominal BF (r = 0.72,r = 0.77, r = 0.76 and r = 0.71, respectively, for WHtR1, WHtR2, WHtR3and WHtR4), after controlling for age, sex and body mass index. There wereno differences between the correlation coefﬁcients obtained between allstudied WHtR and each whole and central BF variable.Conclusions: Waist-to-height ratio was found a suitable BF marker in thepresent sample of NAFLD patients and the strength of the relationshipbetween WHtR and both whole and central BF was not altered by usingdifferent WCmp in the present sample of NAFLD patients.

2016-09-07Journal article

Open access