Analysis and Comparison of the Nutritional Status of Adolescents Utilizing Different Anthropometrics Indices

Objectives: Assessing nutritional status, verify anthropometric differences and compare the prevalence of inadequate nutritional status measured by different anthropometric indices between sexes in adolescents. Method: 304 adolescents between the ages of 14 and 18 (boys 16.0 ± 1.2 and girls 15.7 ± 1.3; average ± SD) were evaluated. Anthropometric data was collected so it was determined the nutritional status through the body mass index (BMI), the Ponderal Index (PI), body fat (BF), waistto-height ratio (WHtR), abdominal circumference (AC) and neck circumference (NC). Results: The analyses of the nutritional status by the BMI, PI, AC and WHtR detected respectively 22, 19.4, 16.4 and 5.6% of the subjects were overweight/obesity with no statistical differences between the sexes. For the BF, 29.6% were determined as obese, with greater prevalence among the girls and for the NC, the prevalence of obesity was 21.4%, more prevalent amongst the boys. Conclusions: The prevalence of overweight and obesity was elevated between adolescents. The boys demonstrated higher body mass, stature and neck circumference, whilst the girls demonstrated higher body fat. There was a high variation in the prevalence of overweight and obesity between the methods. The use of more than one anthropometric method for assessing nutritional status is proven to be an interesting strategy for the accurate detection of overweight /obesity in adolescents.


Introduction
Obesity is considered to be the most ascendant chronicle disease in the world which reaches all age groups and social classes, both in developed countries and lower developed countries [1].In Brazil, the comparison between The National Family Budget Survey (NFBS, 1974(NFBS, /1975) and the Living Standards Measurement Survey (LSMS, 1996/1997), showed that the percentage of adolescents who are overweight has more than tripled within two decades, from 3.7% to 12.6%, whilst the low weight had greatly reduced [2].The results of the Household Budget Survey (HBS) conducted in 2008/2009 show that overweight and obesity in adolescents was 25.4%, which represents the double compared to the research of the previous decade [3].These data are of concern since evidences show that excess weight in young people is a predictor of risk for its maintenance in adulthood [4].
Disorders resulting from obesity in adolescents include cardiovascular and metabolic diseases [5], which highlight the need for an accurate diagnosis for the prevention and early treatment of obesity.In the nineteenth century, it was developed the body mass index (BMI), which is a measurement of nutritional status which uses only body weight and height measurements [6].Because of its convenience, low cost, being easily applied and also strongly associated with body fat, the BMI was widespread and used in population studies [7].Later other equations were developed using the same measures [8] or other methods that estimate the body fat by skinfolds [9] and, even though they are less practical, they determine with some precision the body fat.
From the initial findings of Vague [10] on the differentiation of the effects of the location of body fat accumulation in adults on the development of diseases, in which he found that fat accumulation in the central region of the body, especially visceral fat, presents greater association with the development of diseases, various anthropometric indices were developed to assess central obesity [11][12][13][14].In children and adolescents, increased visceral fat has also been associated with early development of chronic diseases such as diabetes, hypertension and dyslipidemia, leading to a number of health risks [15].Thus, more recently, some studies have been developed in order to validate these anthropometric methods for the evaluation of central obesity in children and adolescents, determining specific cutoff points according to sex and age [16,17].
Although the development of different methods of assessment of nutritional status can enable the determination of different aspects of body fat, they can provide contradictory results, leading to doubts regarding the diagnosis of the subject and consequently the approach to be adopted.For that reason, this study aimed to evaluate the nutritional status, verify anthropometric differences and compare the prevalence of inadequate

Methodology Sample
It was realized a cross-sectional study with a sample of 304 adolescents (194 boys) aged between 14 and 18 years (boys 16.0 ± 1.2 and 15.7 ± 1.3 girls), technical high school students from a Campus of the Federal Institute of Technological Education of Minas Gerais -Brazil.In a total of 473 students aged between 14 and 18 regularly enrolled in the fulltime integrated technical education in the school, 304 students (64.3%) completed all measurements.After collecting the data, the results were reported individually to the participants during a class in which it was discussed the risk of inadequate nutritional status (underweight, overweight, general and central obesity) and appropriate guidelines to minimize them.The study complied with the ethical criteria for research and was approved by the Ethics Committee of Human Research of the Federal Institute of Education, Science and Technology of southeast Minas Gerais, opinion number 03/2012.Consent was obtained from all children and their parents/guardians.

Procedures
The measures were collected by physical education teachers with experience in anthropometric techniques during their physical education classes, as part of regular physical assessment to which all of the students are subjected.Each teacher was responsible for one anthropometric measure in all students.
The assessment of the adolescents' nutritional status was conducted by anthropometry, using body mass, height, neck, waist and abdomen circumferences, besides triceps skinfolds and medial calf.The body mass and height measurements were collected with the student on light clothing and barefoot.The neck circumference measurement was taken at the point just inferior to the laryngeal prominence; the waist at the point of the smallest circumference and the abdomen above the navel, following the recommendations of Callaway et al. [18].The triceps and medial calf skinfolds were measured on the right side of the body in triplicate, recording the average of these measurements.The triceps skinfold thickness was measured with the subject standing, in the middle part of the posterior arm region and the medial calf in the region of greatest circumference in the leg, with his leg relaxed and forming a right angle (90°) with his thigh, according to Harrison et al. [19].
To measure the body circumferences, body weight, height and skinfold thickness, it was, respectively, used a metal anthropometric tape with accuracy of 1 mm (Cescorf, Brazil); a portable digital scale with a maximum load of 150 kg and precision of 100 g (Lider LD1050, Brazil), a stadiometer with graduation of 0.1 cm (Sanny, Personal Caprice, Brazil) and a caliper (Lange, Cambridge Scientific Industries, USA) with accuracy of 1 mm.

Statistical Analysis
Initially, it was applied the Kolmogorov-Smirnov test to assess the normal distribution of data.Descriptive statistics was performed using the average, standard deviation, median, minimum and maximum value for each variable analyzed.The percentage distribution of overweight or obesity prevalence for each of the anthropometric methods used was also calculated.To compare the variables collected between the sexes, it was used the T test for independent measures when the variables showed normal distribution and the Mann-Whitney test when at least one of the groups did not show normal distribution.To analyze differences in prevalence between the sexes, it was used Chi-square test.Statistical analyses were performed using a statistical software (SPSS, version 20.0, Germany) and for all, it was adopted a significance level of p <0.05.

Results
In table 1, it can be observed the characteristics of the sample investigated.Boys showed statistically higher values for weight, height, PI and NC compared to girls.On the other hand, the girls had higher values of body fat.For the other anthropometric variables, significant differences were not identified between the sexes.Table 2 presents the percentages and absolute numbers of boys and girls and the whole sample, ranked within normality limits and the ones that exceeded the criteria of adequacy for each of the anthropometric indices.There was no difference in the prevalence of overweight or obesity between the sexes using the BMI results, PI, AC and WHtR, while for the BF, there was a higher prevalence of obesity among girls and the NC

Discussion
Evaluating the boys, the inadequacy of nutritional status measured by different anthropometric indices ranged between 5.2% and 33.5%.Among girls, these percentages ranged between 6.4% and 46.4%.The prevalence of overweight measured by BMI was higher than the ones found in other national studies with similar samples [24,25], it was also observed in the present study mean values of body fat higher than the ones found by Junior et [26], both for and girls.
These prevalences are very high and also higher than those found for the Brazilian population, especially for boys [3], which raises a concern about adolescent health, requiring interventional actions to improve the observed situation.As it has been observed high prevalence of physical inactivity among adolescents [27] and excessive consumption of foods high in fat and high caloric density [28], which are factors associated with the development of obesity, interventions focusing on the insertion of regular physical activity and diet quality improvements are proven to be important actions to control the nutritional status.Considering that adolescence is a stage in which the habits tend to be maintained even in adulthood, It is held an opportunity to intervene in health education, therefore it could be established healthy habits of life aiming health promotion.
Analyzing the anthropometric variables between the sexes (Table 1), body weight, height and neck circumference were significantly higher in boys, while the body fat was higher in girls.These findings are in agreement with the adolescent stage of development in which, by action of specific sex hormones, there are differences in anthropometric aspects between boys and girls, called sexual dimorphism [29].In adolescents after the spurt of growth and under the action of testosterone, boys have greater development of body mass, muscle and height than girls, and these in turn under the action of estrogen have a higher body fat accumulation [29].
Comparing the prevalence of overweight/obesity among boys and girls evaluated by different methods, the differences were only found between the NC and the BF.In addition to the physiological differences by sexual dimorphism, behavioral differences may determine the differences in the prevalences between the methods.Some studies have shown that girls are more sedentary than boys [30,31].This factor may be associated with a lower muscle development and an increase in deposits of body fat in girls at a level beyond the one determined by sex differences.Thus, the methods that assess overweight (BMI and PI) or central adiposity (AC and WHtR) have the limitation of not determining body composition, eventually equalizing the overweight prevalence between boys and girls.Despite this limitation, it has been shown that these methods have high validity in the detection of body fat [32][33][34].Thus, in assessing the nutritional status of adolescents, the concomitant use of more than one anthropometric method proves to be an important strategy for detecting individuals with overweight/obesity, especially if one of the methods used determines the body composition, like the method analyzing skinfolds.
The NC showed opposite result to the BF, in which the prevalence of obesity was much higher in boys.Unlike waist circumference, which high values are determined by excess fat, while muscle mass has little influence on it, the NC is influenced by both body fat and muscle mass.Therefore, a hypothesis to explain the higher prevalence in boys may be related to the fact that NC was influenced by muscle mass.That's because many of the subjects assessed as obese by the NC were evaluated by BMI or the BF as normal.Likewise, the lower muscle mass of the girls resulted in a low prevalence of obesity when measured by the NC, which may represent a limitation of this method.

Conclusion
The results obtained in this study showed a high prevalence of overweight and obesity in adolescents, pointing to the need of interventions to reduce the observed values.
The comparison of anthropometric parameters between boys and girls determined a greater body mass, height and circumference of the neck for boys, while girls presented higher body fat, consistent results and normal during the stage of adolescence, where sexual dimorphism is pronounced.
The differences in prevalence between the sexes measured by different methods were observed for the NC and the % BF.Despite the different methods are valid according to literature, the use of more than one anthropometric method for assessing nutritional status of adolescents is indicated, aiming at a more accurate diagnosis.Open Access n H U B f o r S c i e n t i f i c R e s e a r c h Citation: Cerqueira LAV, Cerqueira MS, Franco FSC, de Faria RC (2015) Analysis and Comparison of the Nutritional Status of Adolescents utilizing Different Anthropometrics Indices.Obes Open Access 1(1): doi http://dx.doi.org/10.16966/2380-5528.102Open Access 2 nutritional status measured by different anthropometric indices between sexes in adolescents.
n H U B f o r S c i e n t i f i c R e s e a r c h Citation: Cerqueira LAV, Cerqueira MS, Franco FSC, de Faria RC (2015) Analysis and Comparison of the Nutritional Status of Adolescents utilizing Different Anthropometrics Indices.Obes Open Access 1(1): doi http://dx.doi.org/10.16966/2380-5528.102Open Access 3 resulted in higher prevalence among boys.
n H U B f o r S c i e n t i f i c R e s e a r c h Citation: Cerqueira LAV, Cerqueira MS, Franco FSC, de Faria RC (2015) Analysis and Comparison of the Nutritional Status of Adolescents utilizing Different Anthropometrics Indices.Obes Open Access 1(1): doi http://dx.doi.org/10.16966/2380-5528.102

Table 1 :
Anthropometric a Significant difference between boys and girls -Mann-Whitney test BM -body mass; BMI -body mass index; PI -ponderal index; BF -body fat; AC -abdominal circumference; NC -neck circumference; WHtR -waistto-height ratio.characteristics of adolescents between 14 and 18 years, values expressed as average, standard deviation, median, minimum and maximum value according to sex.
Significant difference of prevalence between boys and girls -chi-square test BM -body mass; BMI -body mass index; PI -ponderal index; BF -body fat; AC -abdominal circumference; NC -neck circumference; WHtR -waistto-height ratio. a

Table 2 :
Prevalence of overweight and obesity in adolescents between 14 and 18 years old, assessed with different anthropometric indices.