99 Journal of Exercise Physiologyonline October 2013 Volume 16 Number 5 Official Research Journal of Editor-in-Chief Tommy the American Boone, PhD, Society MBA of Exercise Physiologists Review Board Todd Astorino, PhD ISSN 1097-9751 Julien Baker, PhD Steve Brock, PhD Lance Dalleck, PhD Eric Goulet, PhD Robert Gotshall, PhD Alexander Hutchison, PhD M. Knight-Maloney, PhD Len Kravitz, PhD James Laskin, PhD Yit Aun Lim, PhD Lonnie Lowery, PhD Derek Marks, PhD Cristine Mermier, PhD Robert Robergs, PhD Chantal Vella, PhD Dale Wagner, PhD Frank Wyatt, PhD Ben Zhou, PhD Official Research Journal of the American Society of Exercise Physiologists ISSN 1097-9751 JEPonline Association Between High Adiposity and Sociodemographic Factors in Adolescents André L. Araújo1, Randall J.A.F. Melo1, Fabiano F. Silva1,2, Renato A. Souza1, Giseli Minatto3, Andreia Pelegrini4, Bianca T. Ramallo5, Cristiano Mostarda5, Wellington R.G. Carvalho5 1 Grupo de Estudos e Pesquisa em Ciências da Saúde (GEP-CS), Instituto Federal de Educação, Ciência e Tecnologia (IFSULDEMINAS), Muzambinho, MG, Brazil, 2Biomedical Engineering Institute. Universidade Camilo Castelo Branco, São José dos Campos, SP, Brazil, 3Universidade Federal de Santa Catarina, Centro de Desportos, Núcleo de Pesquisa em Cineantropometria e Desempenho Humano, Florianópolis, SC, Brazil, 4 Universidade Estadual do Estado de Santa Catarina, Centro de Ciências da Saúde e do Esporte, Grupo de Estudo e Pequisa em Cineantropometria, Florianópolis, SC, Brazil, 5Universidade Federal do Maranhão, Departamento de Educação Física, São Luís, MA, Brazil ABSTRACT Araújo AL, Melo RJAF, Silva FF, Souza RA, Minatto G, Pelegrini A, Ramallo BT, Mostarda C, Carvalho WRG. Association Between High Adiposity and Sociodemographic Factors in Adolescents. JEPonline 2013;16(5):99-106. The purpose of this study was to investigate the association between adiposity and sociodemographic factors such as gender, age, socioeconomic status, and area of residence in adolescents 11 to 16 yrs of age living in a Brazilian city of the medium human development index (IDH index). Anthropometric variables that were measured included body mass, height, sum of skinfold thickness of the triceps and subscapular (Σ2DC) to calculate the percentage of body fat (%BF). The Mann-Whitney U Test, chisquare test, and binary logistic regression were used to evaluate the data. Statistical significance was set at P<0.05. The findings indicate that increased body fat was observed in 11.8% of the sample. The girls showed higher Σ2DC (P=0.001) and %BF (P=0.001) than the boys. There were no statistical associations between the increased body fat and the other sociodemographic factors. The findings suggest that it is important to implement health education programs for this age group to help decrease the adolescents’ predisposition to elevated body fat. Key Words: Anthropometry, Body Composition, Obesity 100 INTRODUCTION Recently, Chaves et al. (5) reported on the occurrence of a nutritional transition in Brazil that involves socioeconomics and demographics factors associated with hypercaloric diets (21). In less than two decades, young children and the adolescent population have gone from being nutritionally deficient to the prevalence of obesity (9). The result is a high incidence of diseases, especially in regards to the adverse effects on health in young adults (6) with increased morbidity and mortality. The obesity epidemic is a problem that affects both the urban and rural areas of Brazil (20). Findings from studies conducted in the United Kingdom and North Ireland (26) and Brazil (17) as to the socioeconomic status that leads to obesity and a reduction in healthy lifestyles. There are numerous anthropometric measures to identify the person who is obese. Aside from various imaging techniques (e.g., magnetic resonance imaging, computerized tomography scanning, and dual X-ray absorptiometry), and bio-impedence analysis, the skinfold measurement test is a common method to determine percentage of body fat and body composition (17,18,30). Yet, while there are no perfect tests to measure obesity, especially since each has various limitations, it is nonetheless important to identify the individual who is obese because the intra-abdominal fat is a risk factor for disease. Given this context, it is critical that preventive actions are taken to help obese teenagers who face statistically greater risks of becoming obese adults (29). In addition, there is a lack of studies in the Campestre city (Minas Gerais, Brazil) that have investigated levels of adiposity and associated factors during adolescence. Thus, the aim of this study was to investigate the association between adiposity and sociodemographic factors (gender, age, socioeconomic status, and area of residence) in adolescents 11 to 16 yrs of age living in a Brazilian city of the medium human development index (IDH index). METHODS Subjects This study consisted of 68 adolescents aged 11 to 16 yrs with a mean age of 13.1 ± 1.2 yrs. Thirtyone (45.6%) were males and 37 (54.4%) were females. A descriptive cross-sectional analytical study was conducted in the Campestre city (Minas Gerais, Brazil). The study followed the guidelines for human subject research in accordance with Resolution 196/96 of the National Health Council. The sample for this study was composed of adolescents 11 to 16 yrs of age. The subjects were enrolled in the 2011 public school year. They were residents in urban and rural areas of the city. The Campestre city has a Human Development Index (HDI) of 0.759 that ranks as a medium HDI (13,22). Procedures In the sociodemographic questionnaire, specific information about the subjects’ gender, date of birth, socioeconomic status, and area of residence was recorded. Chronological age was established in accordance with the procedures of Eveleth and Tanner (8). The economic profile of each subject was verified in accordance with the criteria of the Brazilian Association of Business and Research – ABEP (2). The instrument that was used estimates the purchasing power of households and classifies the subjects’ as A, B, C, D, and E in accordance with their accumulation of material goods, housing conditions, number of domestic servants, and education level of the head of household. Anthropometric measurements were performed in accordance to the standard procedures (15). Body weight was measured in kilograms (kg) using a digital scale (Seca®) with a resolution of 100 grams (g). Height was measured in meters (m) using a vertical stadiometer (Seca®) to the 0.1 centimeters 101 (cm). Skinfold thickness of the posterior arm (triceps, TR) and the subscapular region (SE) were measured in the right hemibody using a caliper (Holtain Tanner-Whitehouse Skinfold Caliper, UK) From these data, the sum of TR +SE (Σ2DC) was used to estimate relative body fat (%BF) by the equations of Slaughter et al. (24). For the classification of %BF, the criteria proposed by Fitnessgram (25) that identifies high adiposity adolescents who exceed cut off points that establish the healthy zone were used. Statistical Analyses The data were analyzed using descriptive procedures (mean, median, standard deviation, and frequency distribution) in the software SPSS (Statistical Package for Social Sciences, Inc., Chicago, IL, USA). Data normality was verified using the Kolmogorov-Smirnov test. The data were not normally distributed even after applying the logarithmic transformation (Log10). For comparisons between means and proportions, the Mann-Whitney U Test for independent samples and Chi-square and Fisher’s Exact tests were used, respectively. Noting that the prevalence of adiposity was lower than 20%, binary logistic regression was used to examined the associations between high body adiposity with sociodemographic factors (gender, age, economic status, and area of residence), for estimating odds rations (OR), and the confidence intervals (CI 95%). All variables were entered into the regression model, which used the method of selection Backward-wald. The level of significance was set at P≤0.05. RESULTS Of the 68 subjects studied, 30 (44.1%) lived in urban areas and 38 (55.9%) lived in the rural area in the Campestre city. Following analysis of the anthropometric and body composition measures (Table 1), statistically significant differences were observed between the genders only for Σ2DC (P=0.001) and %BF (P=0.001) with the higher values for girls versus boys. The anthropometric variables of weight and height did not differ between the genders (P>0.05). Table 1. Chronological Age, Anthropometric, and Body Composition According to Gender. Variables Male (n=31) Female (n=37) Age (yrs) M ± SD 13.2 ± 1.3 Md 13.0 CI (95%) 12.7-13.7 M ± SD 13.0 ± 1.1 Md 13.0 CI (95%) 12.6-13.4 Body Mass (kg) 50.3 ± 11.8 51.0 46.0-54.6 54.1 ± 11.9 53.8 50.1-58.0 Height (m) 1.61 ± 0.1 1.63 1.57-1.65 1.57 ± 0.1 1.58 1.54-1.60 Σ2DC (mm) 17.2 ± 6.1 15.0 14.9-19.4 25.8 ± 10.5* 24.2 22.3-29.3 BF (%) 15.9 ± 5.2 14.7 14.0-17.8 22.5 ± 6.7* 22.1 20.2-24.7 M: mean; ±SD: standard deviation; Md: median; Σ2DC: sum of skinfold thicknesses of triceps and subscapular; and percentage of body fat (%BF); *P≤0.05 indicates difference between genders (Mann-Whitney U Test). The high adiposity was observed in 11.8% of the sample. No associations were observed (P>0.05) in the high adiposity with the variables studied (Table 2). 102 Table 2. Data of Absolute (n) and Relative (%) Frequence of High Adiposity According to Sociodemographic Factors. Adequate Adiposity High Adiposity Variables Gender (n=68) Female Male Age (yrs) (n=68) 11 to 13 14 to 16 Socioeconomic Status (n=68) Low (D+E) Mean (C) Residense Area (n=68) Urban Rural n % n % 33 27 89.2 87.1 04 04 10.8 12.9 P value 0.540 0.588 39 21 88.6 87.5 05 03 11.4 12.5 0.522 12 48 92.3 87.3 01 07 7.7 12.7 36 24 94.7 80.0 02 06 5.3 20.0 0.068 Fisher’s Exact Test Table 3 shows the odds ratios of association between body adiposity and high sociodemographic factors. There were no statistically significant observations in both the crude and adjusted analysis for high body fat with sociodemographic factors (P>0.05). Table 3. Association Between Adiposity and High Sociodemographic Factors Assessed by Odds Ratio and Confidence Interval of 95%. High Adiposity Variables OR Gender Female Male Age (yrs) 11-13 14-16 Socioeconomic status Low (D+E) Mean (C) Area of residence Urban Rural CI 95% P OR* CI 95% 0.790 1.0 1.2 0.395 2.0 1.0 0.3-5.30 0.4-9.9 0.889 1.0 1.1 0.837 1.0 0.8 0.2-5.10 0.2-4.2 0.616 1.0 1.75 0.603 1.8 1.0 0.2-15.60 0.2-17.4 0.080 1.0 4.5 0.8-24.20 P 0.057 1.0 5.6 0.9-32.8 OR: odds ratio; CI 95%: confidence interval of 95%, P: level of statistical significance; *OR: adjusted for the sociodemographic factors (gender, age, socioeconomic status, and area of residence). Binary logistic regression. 103 DISCUSSION This study examined the association between high adiposity and sociodemographic factors (gender, age, socioeconomic status, and area of residence) in adolescent mans and females, 11 to 16 yrs of age, living in a city of medium HDI. The findings indicate that there were higher values of Σ2DC and %BF for girls than boys. In general, the values were consistent with other studies (4,11,27), and could be explained by sexual dimorphism. The differences between the genders occur in response to genetic determinants, hormonal and environmental influences, working since the prenatal period and presenting variability in its progression at the time of puberty (27). In a cross-sectional study, Gültekin et al. (11) evaluated 332 boys and 269 girls. They showed clear evidence of sexual dimorphism in the pattern of body fat, with girls showing higher body fat than boys. Carvalho et al. (4) in a more recent cross-sectional study involving public school students of both genders, 8 to 18 yrs, observed that with advancing age higher values of body fat mass and %BF for girls than boys. In the present study, the body composition variables followed an expected result. Our findings indicate a high adiposity in 11.8% of the subjects, which is higher than the 3 to 11.2% reported in the other studies (12,20) and yet, it is lower than some studies (1,14,17) with a range of 17.4% to 25.6%. It is known that obesity in adolescence tends to persist into adulthood with increased morbidity (19) and psychological problems. Accordingly, changes in lifestyle, especially regarding physical activity can help prevent and treat obesity. This thinking is substantiated by the work of Ronque et al. (23), whose findings suggest that adequate aerobic fitness may contribute to the reduction of risk factors for cardiovascular disease (7) as well as assist in the control of body fat. In the present study, no significant association was observed between body composition and high sociodemographic factors. This is in agreement with earlier studies (4,12,14). In 2011, Minatto et al. (17) in a cross-sectional study with adolescent boys and girls (14 to 17 yrs of age) from a town with a low to medium HDI showed the prevalence of inadequate body composition was 24.1%. Inadequate indices of adiposity were more prevalent among adolescent males from medium to high socioeconomic strata; whereas, the age of 14 to 15 was a protective factor against inadequate body composition compared to older ages (16 to 17 yrs of age). Terres and colleagues (28) reported that there was no association of body composition with 15 to 18 yrs of age. But, they did report higher rates of adiposity in 15 to 16 yrs olds versus 17 to 18 yrs olds. Additionally, Martorell et al. (16) showed that the country's economic development seemed to interfere in the magnitude of the association between body composition and sociodemographic data. The literature suggests that adolescents living in urban areas have a higher risk of inadequate body composition compared to those living in the rural area (20). To our understanding, this study is the first cross-sectional, descriptive analysis of sociodemographic factors and adiposity in adolescent subjects in the Campestre city. While the lack of studies with similar criteria makes it difficult to compare our results, the findings do provide important information that adds to the discussion regarding adolescents who have experienced high adiposity between 11 and 16 yrs of age. As to the likelihood of the subjects developing future health problems (10), our results should serve as a warning of the association between adiposity and cardiovascular disease, diabetes mellitus, and hypertension (3,28). 104 Limitations This study has the limitations inherent of cross-sectional studies: (a) the establishment of a causal relationship between the outcome and the variables investigated; (b) the loss of part of the sample (79.6%) for non-compliance by the parents; (c) not attending at school on the day of the assessment; and (d) the bias that resulted from the subjects who failed to completely fill out the socioeconomic questionnaire. CONCLUSIONS The findings indicate that increased body fat was observed in 11.8% of the sample. The girls showed higher Σ2DC and %BF than the boys. There were no statistical associations between the increased body fat and the other sociodemographic factors. 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