**4.1 Body mass index**

*Weight Management*

stand out.

(MRI), and ultrasonography (US).

**3. Assessment of nutritional status**

of developing chronic diseases in adulthood [32].

**4. Assessment and diagnostic anthropometric**

international reference standard [32].

similar up to 5 years of age [32].

Visceral fat can be assessed by measuring waist circumference or by means of imaging tests, such as computed tomography (CT), magnetic resonance imaging

The assessment of nutritional status aims to verify growth and body proportions in an individual or in a community, with a view to establishing intervention attitudes. Thus, the standardization of the evaluation to be used for each age group is of fundamental importance, thus standardizing the criteria used by the health team [32]. With regard to the identification of cases of obesity in children, an important issue has been discussed, that is, which is the most accurate method to classify it [6]. When defining methods for assessing the nutritional status, those which best detect the nutritional problem that is intended to be corrected in the study population should be chosen. The costs for its use, the level of personal skill required to apply them properly, the time needed to perform them, the receptivity on the part of the population studied, and the possible health risks must be considered [32] . Determining obesity is, establishing excess body fat [14]. This concern is justified by the increase in the prevalence of obesity worldwide and the potential risks

Among the various methods, anthropometric diagnosis and imaging diagnosis

Anthropometry, which consists of assessing the physical dimensions and the global composition of the human body, has proved to be the single most used method for nutritional diagnosis at the population level, especially in childhood and adolescence, due to its ease of execution, low cost, and innocuity. Based on the publications of Jellife, edited by WHO, in the 1960s, based on studies that had started in the 1950s, anthropometry was systematized as a method of assessing nutritional status. It was from these studies that anthropometry developed rapidly in industrialized countries, which only occurred in the mid-1970s in developing countries. Since then, anthropometry has constantly evolved, being a useful method in population, clinical, and intervention studies, and its application has enabled advances in interpretations and in the search for mathematical formulations that improve the accuracy of body compartment estimation and its predictive power. Since 1978, WHO has adopted data from the National Center for Health Statistics (NCHS) as an

Anthropometric values represent, at the individual or population level, the degree of adjustment between the genetic potential for growth and the favorable and harmful environmental factors. The ideal anthropometric pattern, then, would be that obtained from populations or ethnic groups whose individuals had enjoyed the opportunity to fully develop their growth potential. In this sense, we use the statistical results obtained from populations in developed areas of the world, or in underdeveloped regions, from human groups of high socioeconomic standard, who probably had better opportunities to fulfill their genotypic growth possibilities [32]. Results from studies around the world have shown and show the possibility of using a single, international benchmark to assess growth and nutrition status in different regions. There is evidence that the growth in height and weight of healthy children of different ethnic origins, submitted to adequate living conditions, is

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Anthropometry, then, even considering its limitations, has been the most widely used method and also the one proposed by WHO [32].

It is recommended that the weight be measured in kilograms (kg), with an anthropometric scale, with the child barefoot, with light clothing and in an orthostatic position in the center of the scale, and that the height be measured in centimeters (cm), using a stadiometer, to the nearest 0.1 cm, with the child barefoot, with the back to the wall, feet together and parallel, in an upright position and looking forward in the horizon line.

The body mass index (BMI) is obtained by dividing body weight, in kilos, by height in square meters [2]; therefore, in kg/m2 [33–35], it is an anthropometric measure widely used to identify excess weight in children, adolescents, and adults [2, 6, 27, 36].

The stratification of nutritional status is obtained from the percentiles in the BMI/age ratio according to gender, from WHO, and allows children to be classified as eutrophic, overweight, or obese. Obesity is diagnosed in children with the percentile is equal to or greater than 97 and, overweight, in children with the percentiles between 85 (inclusive) and 97 [33–35].

The following BMI scores for age are considered, according to the WHO [33–35], illustrated in **Figure 1**.

The values of these anthropometric data should always be analyzed according to the child's age and sex, which are the main determinants of its evolution [2]. Although they are usual and simple procedures, they must be applied carefully, with standardization, and the instruments used must be calibrated frequently [32].

Obesity in children is not defined by an absolute number, but by a percentile [2, 37]. To establish a comparison of a set of anthropometric measurements with a reference standard, several scales can be used, the most common being the percentile and the Z score [32].

The percentiles are derived from the distribution in ascending order of the values of a parameter, observed for a given age or sex; the classification of a child


#### **Figure 1.**

*Reference values for diagnosing nutritional status using BMI curves for age. World Health Organization, Geneva (2000, 2006 and 2007).*

in a given percentile allows to estimate how many children, of the same age and sex, are greater or lesser in relation to the evaluated parameter [2, 32]. The Z score means, in practical terms, the number of standard deviations that the data obtained are removed from their reference median [32].

The WHO Classification can be used for children regardless of age. Regarding the assessment of childhood obesity, the following criteria can be used: weight/ height ratio equal to or greater than 120%; percentile equal to or greater than 97; or Z score equal to or greater than +2.0 [32].

To monitor growth, the curve (growth graph) is used in at least three successive measurements of weight and height, with intervals compatible with their growth rate according to age, allowing to assess the nutritional process. This instrument is extremely useful in establishing situations of nutritional risk [32].

Such curves are essential for both the diagnosis and the assessment of the patient's evolution during treatment. Only by viewing the child's graph can it be seen how small variations in weight and, consequently, in BMI can be significant [2].

The assessment of body composition becomes difficult in children due to its constant change during growth, in addition to not knowing what percentage of body fat increases the risks in relation to their health. It is mainly indicated to verify changes presented by children undergoing treatment for obesity [32]. When interpreting the data obtained in nutritional assessment, sexual maturation criteria should also be considered, given the great individual variability in the maturation process [2, 32].

BMI validity is based on the good correlation it presents with total body fat, especially with the amount of internal fat. However, it does not distinguish between fat mass and lean mass, making it difficult to differentiate between overweight with excess fat and that with hypertrophy of muscle mass [32, 36]. In addition, it does not determine the distribution of body fat [6] and does not reflect stunting, common among children of low socioeconomic status [32].

However, its ease of measurement must be considered since it uses anthropometric data of weight and height, which are easy to obtain and have good reproducibility [7, 32].

#### **4.2 Waist circumference**

The waist circumference (WC) defined by measuring the smallest circumference between the iliac crest and the costal margin is, in particular, a better predictor of visceral obesity, a condition that represents a high risk for the development of chronic noncommunicable diseases such as diabetes mellitus type 2, MS, HE, and cardiovascular diseases and, thus, it has been highlighted in national and international studies [6, 8, 38].

The use of this measure in screening and in primary health care helps in the early diagnosis and in the identification of those potential candidates to manifest such diseases in adulthood [1]. This measure is noninvasive, uses a minimum of equipment when compared to laboratory techniques, is fast to apply, easy to be used by trained evaluators, and is very affordable [38].

Waist circumference (WC) is measured in centimeters (cm), using a flexible and inelastic measuring tape, with the child in an orthostatic position, at the midpoint between the iliac crest and the costal rim, under clothing and at the end of a normal exhalation.

The authors stressed the importance of measuring waist circumference as a mandatory part of the pediatric semiological examination [22].

The classification of WC for each child is performed according to age, sex, and the percentiles of McCarthy et al. [39], considering the 90th and 95th percentiles to identify overweight and obesity, respectively (**Figure 2**).

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practice [6].

**Figure 2.**

calculations [39].

*Diagnostic Methods in Childhood Obesity DOI: http://dx.doi.org/10.5772/intechopen.92880*

**4.3 Relationship between BMI and WC**

*\* 6 + = group of children aged 6.00–6.99 years.*

including in children and adolescents [7, 8].

Regarding the knowledge produced about the use of BMI or WC to assess the pattern of body fat, scholars of the subject in search of an answer demonstrated that there is a strong correlation coefficient between both measures, indicating that the waist circumference can determine, satisfactorily, children with high BMI [6, 7]. Investigations found important correlation values between BMI and WC, suggesting the joint use for the diagnosis of obesity, overweight, and central obesity [6],

*Parameters for classifying waist circumference between genders, adapted from McCarthy et al. [39].* 

BMI expresses changes that may occur in the distribution of fat, but does not verify the pattern of body fat. Thus, correlating this measure with other anthropometric measures is necessary, considering that the type of deposit of fat distribution is related to the health prognosis. However, WC is the measure that best represents the distribution of visceral fat and this, in turn, is more related to metabolic changes than subcutaneous fat, indicating the risk of children or adolescents to develop cardiovascular disease in future life. In addition, the relationship of this anthropometric measure with dyslipidemia, with arterial hypertension, and with the metabolic syndrome is evidenced in the literature and, therefore, should support professional

McCarthy et al. stated that BMI may be a less sensitive indicator of fat among children and does not provide any indication of fat distribution. Information about

WC can be adopted as an alternative or additional measure to BMI in children. It is a direct measure that requires simple and inexpensive equipment, with the registration of a single value. BMI requires more complex equipment and mathematical

Researchers stressed the difference between ethnic groups and the importance of developing specific population patterns, as visceral adiposity is highly variable in

WC in children can be as useful as BMI in population studies [39].


**Figure 2.**

*Weight Management*

are removed from their reference median [32].

Z score equal to or greater than +2.0 [32].

in a given percentile allows to estimate how many children, of the same age and sex, are greater or lesser in relation to the evaluated parameter [2, 32]. The Z score means, in practical terms, the number of standard deviations that the data obtained

The WHO Classification can be used for children regardless of age. Regarding the assessment of childhood obesity, the following criteria can be used: weight/ height ratio equal to or greater than 120%; percentile equal to or greater than 97; or

To monitor growth, the curve (growth graph) is used in at least three successive measurements of weight and height, with intervals compatible with their growth rate according to age, allowing to assess the nutritional process. This instrument is

The assessment of body composition becomes difficult in children due to its constant change during growth, in addition to not knowing what percentage of body fat increases the risks in relation to their health. It is mainly indicated to verify changes presented by children undergoing treatment for obesity [32]. When interpreting the data obtained in nutritional assessment, sexual maturation criteria should also be considered, given the great individual variability in the maturation process [2, 32]. BMI validity is based on the good correlation it presents with total body fat, especially with the amount of internal fat. However, it does not distinguish between fat mass and lean mass, making it difficult to differentiate between overweight with excess fat and that with hypertrophy of muscle mass [32, 36]. In addition, it does not determine the distribution of body fat [6] and does not reflect stunting, com-

However, its ease of measurement must be considered since it uses anthropometric data of weight and height, which are easy to obtain and have good

The waist circumference (WC) defined by measuring the smallest circumference between the iliac crest and the costal margin is, in particular, a better predictor of visceral obesity, a condition that represents a high risk for the development of chronic noncommunicable diseases such as diabetes mellitus type 2, MS, HE, and cardiovascular diseases and, thus, it has been highlighted in national and

The use of this measure in screening and in primary health care helps in the early diagnosis and in the identification of those potential candidates to manifest such diseases in adulthood [1]. This measure is noninvasive, uses a minimum of equipment when compared to laboratory techniques, is fast to apply, easy to be used

Waist circumference (WC) is measured in centimeters (cm), using a flexible and inelastic measuring tape, with the child in an orthostatic position, at the midpoint between the iliac crest and the costal rim, under clothing and at the end of

The authors stressed the importance of measuring waist circumference as a

The classification of WC for each child is performed according to age, sex, and the percentiles of McCarthy et al. [39], considering the 90th and 95th percentiles to

mandatory part of the pediatric semiological examination [22].

identify overweight and obesity, respectively (**Figure 2**).

Such curves are essential for both the diagnosis and the assessment of the patient's evolution during treatment. Only by viewing the child's graph can it be seen how small variations in weight and, consequently, in BMI can be significant [2].

extremely useful in establishing situations of nutritional risk [32].

mon among children of low socioeconomic status [32].

reproducibility [7, 32].

**4.2 Waist circumference**

international studies [6, 8, 38].

a normal exhalation.

by trained evaluators, and is very affordable [38].

**90**

*Parameters for classifying waist circumference between genders, adapted from McCarthy et al. [39]. \* 6 + = group of children aged 6.00–6.99 years.*
