Article

Association between different growth curve definitions of overweight and obesity and cardiometabolic risk in children

Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, Que.
Canadian Medical Association Journal (Impact Factor: 5.96). 04/2012; 184(10):E539-50. DOI: 10.1503/cmaj.110797
Source: PubMed

ABSTRACT

Overweight and obesity in young people are assessed by comparing body mass index (BMI) with a reference population. However, two widely used reference standards, the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) growth curves, have different definitions of overweight and obesity, thus affecting estimates of prevalence. We compared the associations between overweight and obesity as defined by each of these curves and the presence of cardiometabolic risk factors.
We obtained data from a population-representative study involving 2466 boys and girls aged 9, 13 and 16 years in Quebec, Canada. We calculated BMI percentiles using the CDC and WHO growth curves and compared their abilities to detect unfavourable levels of fasting lipids, glucose and insulin, and systolic and diastolic blood pressure using receiver operating characteristic curves, sensitivity, specificity and kappa coefficients.
The z scores for BMI using the WHO growth curves were higher than those using the CDC growth curves (0.35-0.43 v. 0.12-0.28, p < 0.001 for all comparisons). The WHO and CDC growth curves generated virtually identical receiver operating characteristic curves for individual or combined cardiometabolic risk factors. The definitions of overweight and obesity had low sensitivities but adequate specificities for cardiometabolic risk. Obesity as defined by the WHO or CDC growth curves discriminated cardiometabolic risk similarly, but overweight as defined by the WHO curves had marginally higher sensitivities (by 0.6%-8.6%) and lower specificities (by 2.6%-4.2%) than the CDC curves.
The WHO growth curves show no significant discriminatory advantage over the CDC growth curves in detecting cardiometabolic abnormalities in children aged 9-16 years.

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Available from: Edgard E. Delvin, Jul 02, 2015
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    • "The probability of comorbidities increased with the severity of obesity (De Onis et al., 2013). A current Canadian study performed on a large sample of three cohorts of children aged 9, 13 and 16 years, respectively, has reported very similar results (Kakinami et al., 2012). Furthermore , the present study demonstrates how vascular alterations behave similarly to other comorbidities reflecting the onset of vascular disease. "
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    ABSTRACT: To compare the association between metabolic and vascular comorbidities and the body mass (BMI)-for-age cut-off criteria from three growth standards [Centers for Disease Control and Prevention (CDC), 2000; World Health Organization (WHO), 2007; Spanish Reference Criteria (Carrascosa Lezcano et al., 2008)] that are used to define being overweight and obese in childhood. A prospective study was conducted in 137 children (aged 8-16 years). Based on BMI-for-age Z-scores according to WHO cut-offs, 59 participants were obese, 35 were overweight and 43 were normal-weight. All participating children were subsequently reclassified applying the CDC and Spanish Reference Criteria. Blood pressure (BP), biochemical variables and vascular parameters (stiffness and intima-media thickness) were analysed. According to WHO and CDC references, 48% and 43% of the children, respectively, were categorised as obese, whereas 16% were considered as obese using the Spanish Reference Criteria. Applying WHO criteria, obese children showed significantly higher levels of insulin, homeostasis model assessment index and most vascular parameters, as well as lower high-density lipoprotein (HDL)-cholesterol than overweight children. Moreover, overweight children showed higher BP, insulin and uric acid, and lower HDL-cholesterol than normal weight children. The CDC criteria yielded similar results, although with fewer differences between obese and overweight children. Applying Spanish criteria, the differences between obese and overweight children disappeared. WHO and CDC BMI-for-age references and cut-offs are useful for defining obesity and being overweight in children because they clearly identify metabolic and vascular comorbidities. The Spanish Reference Criteria underdiagnose obesity because overweight children show comorbidities typical of the obese.
    Full-text · Article · Jun 2013 · Journal of Human Nutrition and Dietetics
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    • "The probability of comorbidities increased with the severity of obesity (De Onis et al., 2013). A current Canadian study performed on a large sample of three cohorts of children aged 9, 13 and 16 years, respectively, has reported very similar results (Kakinami et al., 2012). Furthermore , the present study demonstrates how vascular alterations behave similarly to other comorbidities reflecting the onset of vascular disease. "
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    ABSTRACT: OBJECTIVE: To examine the association between cardiovascular risk and childhood overweight and obesity using the BMI cut-offs recommended by the WHO. DESIGN: Children were classified as normal weight, overweight and obese according to the WHO BMI-for-age reference. Blood pressure, lipids, glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR) and uric acid levels were compared across BMI groups. ANOVA and tests of linearity were used to assess overall mean differences across groups. Crude and adjusted odds ratios were calculated for adverse plasma levels of biochemical variables. SETTING: Paediatric care centres. SUBJECTS: Children (n 149) aged 8-18 years. RESULTS: About 37 %, 22 % and 41 % of children were classified respectively as normal weight, overweight and obese. There were significant linear mean differences between BMI groups in systolic blood pressure, HDL-cholesterol, TAG, insulin, HOMA-IR and uric acid. Obese children were 10·6 times more likely than normal-weight children to have hypertension; OR for other associations were 60·2 (high insulin), 39·5 (HOMA-IR), 27·9 (TAG), 16·0 (HDL-cholesterol), 4·3 (LDL-cholesterol) and 3·6 (uric acid). Overweight children were more likely than normal-weight children to have hypertension (OR = 3·5), high insulin (OR = 28·2), high HOMA-IR (OR = 23·3) and high TAG (OR = 16·1). Nearly 92 % and 57 % of the obese and overweight children, respectively, had one or more risk factor. CONCLUSIONS: Obesity and overweight defined using the WHO BMI-for-age cut-offs identified children with higher metabolic and vascular risk. These results emphasize the importance of prevention of overweight and obesity in childhood to reduce cardiovascular risk.
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