چاپ صفحه |  صفحه نخست سامانه |  نویسندگان |  اطلاعات تفضیلی |  دانلود مقاله | علوم پزشکی کرمانشاه |
| کد مقاله | 11806 |
| عنوان فارسی مقاله | |
| عنوان لاتین مقاله | Fat Mass Index (FMI) or Body Mass Index (BMI)? Which is more accurate in diagnosing childhood obesity? |
| نوع ارائه | سخنرانی |
| عنوان کنگره / همایش | 11th international Conference on Childhood Obesity and Nutrition |
| نوع کنگره / همایش | بین المللی |
| کشور محل برگزاری کنگره/ همایش | اسپانیا |
| شهر محل برگزاری کنگره/ همایش | بارسلون |
| سال انتشار/ ارائه شمسی | 1396 |
| سال انتشار/ارائه میلادی | 2018 |
| تاریخ شمسی شروع و خاتمه کنگره/همایش | 1396/12/24 الی 1396/12/25 |
| آدرس لینک مقاله/ همایش در شبکه اینترنت | https://childhoodobesity.conferenceseries.com/2018 |
| آدرس علمی (Affiliation) نویسنده متقاضی | 2.0000 |
| نویسنده | نفر چندم مقاله |
|---|---|
| امیر باقری | دوم |
| مهنوش صمدی | اول |
| عنوان | متن |
|---|---|
| کلمات کلیدی | Fat Mass Index, Body Mass Index, Obesity |
| چکیده | As for increasing prevalence of obesity in children, it is essential to use a measure that accurately diagnose obesity in children. The purpose of this study was to determine the sensitivity and specificity of body mass index (BMI) compared to fat mass index (FMI) as a measure of child actual obesity. This cross-sectional study was conducted in 580 girls aged 8-10. In this study FMI at or above 90th percentile of age specific data (FMI 6.9 kg/m2) are known as obese and FMI less than 90th percentile are known as normal weight. ROC curves to evaluate performance BMI against FMI was used to determine the actual obesity. The kappa test to determine whether the two criteria were used to define obesity in children. Mean and SD BMI and FMI in children was 19.4 ± 3(kg/m2) and 6 ± 2.1(kg/m2) respectively. The area under the ROC curve 83% was calculated and the sensitivity and specificity and cut-off point of BMI compared with FMI was calculated 21.2 kg/m2 and 59 percent and 97 percent. The agreement between BMI = 21.2 kg/m2 and FMI= 6.9 kg/m2 in determine obesity was 0.5. In this study the BMI sensitivity was poor and only 59% of the children who were obese based on FMI, were also obese based on BMI and 3% of the children, who were identified as non-obese based on FMI, were obese based BMI. FMI seems more accurate measure of obesity than BMI is, however, more research is needed in this area. |
| متن مقاله | Introduction Overweight is the most important nutritional-health problem of children and teenagers in developed countries. Because of urbanization, life style change and modernization, the increasing trend of overweight in developing countries is a warning for health authorities. Prevalence of overweight among children is rapidly increasing all over the world 1 so that, in the US, it reached 18.8% during 2003-2004 among 6 to 11-year-old children 2. Based on CDC (Centers for Disease Control) standards, the BMI of equal to or more than the 95th percentile and within 85 to 95 are categorized as overweight and at risk of overweight, respectively. A study conducted in 2004 in Iran showed the prevalence of overweight risk and overweight among elementary school children as 9.8% and 4.4%, respectively 3. Prevalence of overweight among elementary school girls of Region 6 in Tehran has been reported as 16%, 6.9% and 6.6%, according to Iranian references, CDC2000 (Centers for Disease Control) and IOTF2000 (International Obesity Task Force), respectively 4. Moreover, prevalence of overweight in elementary school children was reported 9.9%, 9.2% and 8% in Chaharmahal-va-Bakhtiary Province 5, city of Yazd 6 and city of Isfahan 7, respectively. Besides its negative mental effects, overweight in childhood has a direct relationship with obesity, hypertension and osteopathy in adulthood; furthermore, it is considered a risk factor for other diseases in adulthood 8. Considering the increasing prevalence of overweight among children, it seems necessary to use a criterion for proper overweight determination in children 9. The studies which have analyzed the role of fat tissue in determining overweight emphasize that distribution of fat tissue in the body could predict cardiovascular diseases, metabolic syndrome and some types of cancers 10; as a result, waist circumference and waist-hip ratio are more precise predictors for mortality and risk of diseases than BMI 11. That is because BMI cannot distinguish fat mass from non-fat mass and evaluate overweight properly 9. According to a report by World Health Organization (WHO), extra body fat in childhood is associated with the increase of body fat in adulthood and risk of chronic diseases. Considering the point that body fat can be measured through different methods like dual X-ray absorption (DXA), bioelectric impedance analysis (BIA) and caliper, it seems necessary to measure body fat besides BMI during childhood 12. Therefore, it is important to consider body fat mass while determining overweight in order to predict outcomes of overweight, which mainly arise from increase in fat mass in the body 9. Many studies have defined overweight in children based on BMI percentiles and have attributed high BMI to high body fat. However, since BMI is always influenced by lean body mass, it may not always result in a precise estimate of body fat. Children who have been placed in the normal range based on their BMI may have high body fat mass and low lean mass. Also, most studies have used body fat percent to determine overweight. As the effect of height is not considered when determining overweight in this method, errors may occur in categorizing people. Therefore, it seems necessary to use a criterion for measuring body fat mass separately while considering the height. FMI (Fat Mass Index) which is obtained from dividing body fat mass (kg) by squared height (m2) can be a proper criterion for predicting body fat mass and overweight. It provides the possibility for considering body fat mass separately and stating it relative to height; it is used in some studies for determining overweight as a better criterion than body fat percent 13. Few studies have been conducted in Iran with regard to FMI evaluation and its comparison with BMI, where they have used caliper for measuring body fat level 14. In the present study, Body Composition Analyzer (BCA) was used instead of caliper to evaluate body fat mass. This device has higher accuracy than caliper and provides proper evaluation of body fat mass in comparison with DXA. In children, BCA shows body fat mass 2.6% more than the real value (DXA) on average while caliper has much lower accuracy and shows more than 6% error in measuring body fat 15. As a result, using this method for evaluating FMI would result in more accurate FMI values than previous studies from Iran. In this study, in addition to using the highly accurate BCA device for evaluating body fat mass, FMI was applied for evaluating overweight in children because it is not affected by body lean mass. Moreover, it was the first study conducted in Iran to determine BMI capability for correct diagnosis of individuals with overweight and normal weight compared with FMI as the real overweight criterion in children. Materials and Methods This descriptive case-control study was conducted in the city of Isfahan in 2010. The participants were elementary school girls (aged 8-10 years) with FMI equal to or more than 7.2 as overweight girls and those with FMI less than 7.2 as girls without overweight. Setting 7.2 as the cut-point was based on the study by Nakao et al. in Japan which was obtained by calculating the 90th percentile of available data on 9-11 year- old girls 16. Since this study was the only experiment that covered different age ranges including the age range considered in the present study, calculated FMI references and applied a device for measuring body composition similar to the one used in this study, its values were used as references for categorizing the participants of this work . Among 410 participants of this study, the 90th percentile FMI was 7.4, which was 0.2 different from the reference calculated by Nakao. It should be mentioned that Iranian studies have not reported any references for FMI thus far and the only study in this field in Iran used caliper for measuring body fat mass and FMI 14. In the present study, 103 individuals with the FMI equal to or more than 7.2 were assigned to the case group and 307 others with the FMI less than 7.2 (as individuals without overweight) were classified in the control group. Ten schools were randomly selected from the school list of Education Office of Isfahan. From each school, 11 and 30 individuals were randomly selected for the case and control groups, respectively. After choosing the cases at each grade, their controls were also selected from the same grades at the same schools. In order to increase research power, 3 children with the closest date of birth were selected from the same class as the control for each case. As the first step, children’s date of birth was collected from their school records and their height, weight and body fat mass were measured. The height of each child was measured using a non-stretchable tape with the accuracy of 0.5 cm while standing barefoot with heals sticking to the wall, straight head and forward look. Their weight was measured while they had the minimum clothes on without any extra accessories using the BCA device with the accuracy of 50 g (Model Tanita 418 MA, made in Japan). Body fat mass was also measured by the same device. Afterwards, FMI was calculated. For the present study, the FMI equal to or more than 7.2, based on the calculated reference of Nakao’s study, was regarded as real overweight in children. Using BMI percentiles of CDC2000 standard, those children with the BMI equal to or more than 95th percentile and those with the BMI less than 95th percentile were categorized as overweight and non-overweight individuals, respectively. Finally, overweight based on BMI was compared with overweight based on FMI and their sensitivity and specificity in determining children with overweight were measured. SPSS statistical software, ver. 16, was used for data analysis. Mean and standard deviation along with Wilcoxon, Mann-Whitney and independent t-test were used for data description and comparison of means, respectively. These tests were selected based on normal distribution of variables in both groups yielded by Kolmogorov-Smirnov test. BMI sensitivity was calculated by dividing the number of children who were overweight using both BMI and FMI criteria by the total number of children with “real” overweight. BMI specificity was also calculated by dividing the number of children who were non-overweight using both criteria of BMI and FMI by the total number of “real” non-overweight children. In order to compare overweight status based on FMI and BMI, χ2 test was applied. Also, p<0.05 was considered as the significance level. Results Means and standard deviations of BMI and FMI in all children were 6±2.1 and 19.4±3 kg/m2, respectively (Table 1). As shown in table 1, means and standard deviations of body fat percent in 8, 9 and 10 year old children were 28±5.8, 28.6±5.3 and 29±5.4, respectively, in which body fat percent increased with age. Similarly, mean of FMI in the participating children increased with age; in the ages of 8, 9 and 10 years old, it was calculated as 5.7, 5.9 and 6.5 kg/m2, respectively. Based on table 2 and with the application of FMI as the real overweight criterion, BMI sensitivity and specificity which were equal to and more than the 95th percentile of the CDC2000 standard for determining overweight were 57.3 and 98.4, respectively. The observed difference in overweight based on these two criteria was statistically significant (p<0.05). Discussion Considering the increasing prevalence of overweight all over the world, it seems necessary to use a precise method for determining overweight. Many health-related problems can be attributed to the increase of body fat mass and overweight. Overweight in childhood endangers health in adulthood 9. Although it is common to use BMI for determining overweight, where only height and weight are needed to be measured, it is not an accurate criterion for overweight evaluation. The first step toward preventing and treating the problems related to overweight is to estimate body fat mass 9. In the present study, means of FMI and BMI in all participating children, using a BCA device were calculated as 6 and 19.4 kg/m2, respectively. The studies conducted in other countries have reported the FMI mean of 4.45 for 11-year-old girls 17, 4.79 and 3.21 for 6- to 8-year-old girls and boys, respectively, 18 and 6.2 for 12-year-old girls 19. In the study of Wells et al., FMI means of 4.5 and 3.2 were reported for 8-year-old girls and boys while their BMI means were 17.1 and 16.5, respectively 20. In the study of Nakao et al., FMI values at the 90th percentile of the data obtained from 6 to 8-year-old boys and girls were 4.8 and 5.3, respectively. In the same study, these values were 6.4 and 7.2 in 9 to 11-year-old boys and girls, respectively 1. In the present study, the 90th percentile of the calculated FMI was equal to 7.4, in which 0.2 difference was observed from the reference value which was calculated at the same age group by Nakao et al. The differences in FMI values in different studies could be attributed to the variations in the methods used for measuring body fat, application of different criteria for categorizing overweight, and also sample size. Considering that no reference values have been specified for FMI yet and it was not possible for the present study to have large samples and determine the 90th percentile rank of FMI due to sampling limitations, the present study used the reference values of the Nakao et al.’s study. In that study, FMI values were calculated age-wise among 522 boys and 649 girls for defining overweight in children within the age range of 3 to 11 years old. In the present study, the relationship between BMI and FMI was analyzed and it was observed that 57.3% of the overweight children based on FMI were recognized overweight based on BMI as well and 98.4% of the children with normal weight based on FMI showed the same status with BMI; in other words, sensitivity and specificity of BMI in comparison with those of FMI as the real criterion of overweight were 57.3% and 98.4%, respectively. Various studies have mentioned low sensitivity of BMI in determining overweight among children. In the study by Haeri-Behbahani, the 90th percentile values of FMI were reported as 5.2, 5.9 and 5.6 for boys, girls and total children, respectively. When FMI as the real criterion of overweight was applied, BMI sensitivity and specificity at equal to or more than the 95th percentile of the CDC2000 standard for determining overweight were reported 43.3 and 99.4, respectively, and the difference observed at the overweight level based on these two criteria was significant. Based on the results of that study, BMI had lower performance in overweight diagnosis in children and FMI was a better criterion than BMI for overweight evaluation in children. The mentioned study used caliper to measure body fat, which has lower accuracy than BCA 14. In the study of Eto et al., the validity of BMI and FMI was evaluated by considering body fat mass of more than 20% and 25% in boys and girls, respectively, as the real criterion of overweight in children and also determining the 90th percentile of the data obtained from calculating BMI and FMI for defining overweight 21. Thus, sensitivities of BMI and FMI were calculated as 37.5 and 68.8 in boys and 30.4 and 42.9 in girls, respectively. In their research, FMI showed higher sensitivity than BMI but both indicators demonstrated lower capability than body fat percent for diagnosing children with overweight. In addition, specificities of BMI and FMI were calculated as 95.5% and 99.5% in girls and 96.4% and 100% in boys, respectively, both of which showed high specificity. Due to observing a correlation between BMI and FMI on the one hand and body fat percent on the other, this study suggested both BMI and FMI as indicators of fat mass 21. Nevertheless, with regard to the correlation between BMI and body fat percent in children, the study of Wells et al. stated that neither BMI nor body fat percent were independent from body fat free mass 20. Sidhu et al. analyzed sensitivity, specificity, and accuracy of BMI in determining high body fat mass by conducting a study on 500 girls within the age range of 6 to 11years old. In this study, the BMI of equal to and more than the 95th percentile of CDC standards was regarded as overweight and the fat mass (measured by caliper) of equal to or more than the 90th percentile was regarded as having high fat mass. This study reported sensitivity, specificity and accuracy as 42%, 85% and 87%, respectively. Also, it concluded that using BMI by itself was not appropriate for determining high fat mass and suggested using another indicator along with BMI for determining overweight and high body fat mass 22. In Zimmerman’s study, BMI sensitivity and specificity compared with body fat percent were determined as the overweight criterion and it was shown that BMI had high sensitivity and specificity in determining overweight among 6 to 12-year-old children. This research concluded that BMI could be an appropriate sign of body fat mass in 6 to 12 year old children 23. The study by Demarath et al. which was conducted on 494 girls and boys within the age range of 8 to 18 years old showed that FMI significantly increased only at high percentiles of BMI. Although means for BMI were similar in girls and boys, FMI was significantly different in the two genders. In this study, with the equal increase in BMI percentile, body fat increase with age in heavier girls was higher than lighter ones. This research concluded that changes in BMI percentiles in children might not properly show changes in body fat mass in the course of time, especially in boys with low BMI 24. Based on the results of his study on 5 to 18 year old individuals, Freedman stated that BMI accuracy as the estimation of body fat mass greatly depended on overweight intensity so that it had high correlation with FMI in children with the BMI more than the 85th percentile and high correlation with fat free mass in children with the BMI less than the 50th percentile. As a result, BMI difference in thin and normal children could arise more from body fat free mass 25. In general, BMI should be used with great caution as an indicator of body fat mass and overweight 17. Body weight is composed of fat mass and fat free masses, both of which can be different among individuals. Based on the results of the present study, BMI compared with FMI as the real criterion of overweight had relatively lower sensitivity and higher specificity; that is, BMI had less capability in recognition of overweight individuals correctly and higher capability in recognition of individuals with normal weight as compared with FMI. Considering that the differences in fat free mass are in most cases the main reason for BMI difference in children, there is no certainty that higher BMI equals higher body fat mass in children 20. Therefore, it is necessary to verify BMI efficiency in determining overweight in children. In addition, it is beneficial to use FMI as an indicator of body fat mass in proportion to height and independent from body fat free mass for correct evaluation of the prevalence of overweight in children 20. Nevertheless, it is recommended to conduct more researches in this field. In the present study, body fat mass of children was measured by BCA, which had much higher accuracy compared to caliper. Previous studies in Iran have used caliper for measuring body fat mass in children. There were limitations in this study. This study was confined to girls only. There was no possibility to conduct this study on a larger sample and to determine the 90th percentile of FMI in the studied population; consequently, the reference values of previous studies were used. Conclusion: Considering the increase in the prevalence of overweight in children and its outcomes in adulthood, it seems necessary to use a precise method for determining overweight. The results of the present study points that FMI could present more precise diagnosis in determining overweight in children since it considers body fat mass in determining overweight on the one hand and is not affected by body fat free mass on the other. Acknowledgment The present study was supported by a grant (no: 91-1-27-17361) from the Vice-chancellor for Research, Tehran University of Medical Sciences, Tehran, Iran. Conflict of Interests Authors have no conflict of interests. Authors' Contributions: HSY carried out the design of the study. HSY and MS developed the study. HSY, MS and LA were responsible for data analysis, and interpretation of results. . MS and KJ were responsible for data gathering. AR was consultant in data analysis. HSY and MS were responsible for manuscript preparation and scientific writing of the manuscript. All authors have read and confirmed the content of the manuscript. References 1. Wells JC. A critique of the expression of pediatric body composition data. Arch Dis Child 2001;85:67-72. 2. Ogden CL, Yanovski SZ, Carroll MD, Flegal KM. The epidemiology of obesity. Gastroenterology 2007;132:2087-2102. 3. Kelishadi R, Childhood overweight, obesity, and the metabolic syndrome in developing countries. Epidemiol Rev 2007;29:62-76. 4. Dorosty A.R, Hodjat P. The study of some obesity associated factors in primary school girls. TUMJ 2002;6(1):1-9. 5. Shahgholian N, Aein F, Deris F. 90th percentile of body mass index (BMI) and some obesity risk factors among 7-12 years old school children, Chaharmahal & Bakhtiary, 2002. JSKUMS 2004;5(4):42-48. 6. Karimi A.A, Atabakhsh A, Taghdisi H. Prevalence of Obesity among primary school childs in yazd. JSSU 1995;1:2-70. 7. Kelishadi R, Pour MH, Sarraf-Zadegan N, Sadry GH, Ansari R, Alikhassy H et al. Obesity and associated modifiable environmental factors in Iranian adolescents: Isfahan Healthy Heart Program, Heart Health Promotion from Childhood. Pediar Int 2003;45(4):435-442. 8. Kain J, Albala C, Garicia I, Andrad M, Obesity in children preschool children. Anthropometric ovulation and socioeconomic determinants. Rev Med Chil 1998;126(3):271-278. 9. Peltz G, Aguirre M, Sanderson M, Fadden M. The role of fat mass index in determining obesity. Am J Hum Biol 2010;22:639–647. 10. Snijder MB, van Dam RM, Visser M, Seidell JC. What aspects of body fat are particularly hazardous and how do we measure them? Int J Epidemiol 2006;35:83–92. 11. van den Brandt PA, Goldbohm RA. Nutrition in the prevention of gastrointestinal cancer. Best Pract Res Clin Gastroenterol 2006;20:589–603. 12. World Health Organization, Expert Committee on Physical Status. Physical Status: The Use and Interpretation of Anthropometry. Geneva, Switzerland: World Health Organization; 1995:420. WHO technical report 854. 13. VanItallie TB, Yang MU, Heymsfield SB, Funk RC, Boileau RA. Height-normalized indices of the body's fat-free mass and fat mass: potentially useful indicators of nutritional status. Am J Clin Nutr 1990;52:953–959. 14. Haeri Behbahani B, Dorosty A.R, Eshraghian M.R. Assessment of obesity in children: Fat Mass Index versus Body Mass Index. TUMJ 2009;67:408-414. 15. Volgyi E, Frances A, Lyytikainen A, Suominen H, Alen M, Cheng S. Assessing Body Composition With DXA and Bioimpedance: Effects of Obesity, Physical Activity, and Age. Obese J 2008;16:700-705. 16. Nakao T, Komiya S. Reference norms for a fat-free mass index and fat mass index in the Japanese child population. J Physiol Anthropol Appl Human Sci 2003;22:293-298. 17. Demerath EW, Schubert CM, Maynard M, Sun SS, Chumlea WC, Pickoff A, et al. To treat or not to treat: comparsion of different criteria used to determine whether weight loss is to be recommended. Nutr J 2006;7:5-11. 18. McCaffrey TA, Rennie KL, Kerr MA, Wallace JM, Hannon- Fletcher MP, Coward WA, et al. Energy density of the diet and change in body fatness from childhood to adolescence; is there a relation? Am J Clin Nutr 2008;87(5):1230-1237. 19. Lohman TG, Ring K, Schmitz KH, Treuth MS, Loftin M, Yang S, et al. Association of body size and composition with physical activity in adolescents girls. Med Sci Sports Exerc 2006;38:1175-1181. 20. Wells JCK, Cole TJ, ALSPAC study team. Adjustment of fat_free mass and fat mass for height in children aged 8 y. Int J Obes Relat Metab Disord 2002;26:947-952. 21. Eto C, Komiya S, Nakao T, Kikkawa K. Validity of the body mass index and fat mass index as an indicator of obesity in children aged 3- 5 year. J Physiol Anthropol Appl Human Sci 2007;23(1):25-30. 22. Sidhu S, Badaruddoza ,Kaur H. Prevalence of Obesity Among Female Children of Amritsar in Punjab with Convenient Indicators. J Hum Ecol 2002;13(4):287-289. 23. Zimmermann MB, Gubeli C, Puntener C, Molinari L. Detection of overweight and obesity in a national sample of 6-12-y-old Swiss children: accuracy and validity of reference values for body mass index from the US Centers for Disease Control and Prevention and the International Obesity Task Force. Am J Clin Nutr 2004;79(5):838-343. 24. Demerath EW, Schubert CM, Maynard M, Sun SS, Chumlea WC, Pickoff A, et al. To treat or not to treat: comparsion of different criteria used to determine whether weight loss is to be recommended. Nutr J 2006;7:5-11. 25. Freedman DS, Wang J, Maynard LM, Thornton JC, Mei Z, Pierson RN. Relation of BMI to fat and fat-free mass among children and adolescents. Int J Obes 2005;29:1-8. Table 1: Mean and standard deviation of anthropometric measurements of subjects across age groups Age (year) 8 (n=213) 9 (n=144) 10 (n=53) Total (n=410) Height (cm) 130.5(5.3) 136.6(6.5) 142.2(6.1) 134(7.1) Weight (kg) 33.2(6.6) 36.4(7.7) 40.4(8.2) 35.3(7.6) Fat mass (kg) 10.7(4) 11.1(4.1) 11.7(4.2) 10.9(4.1) Fat Mass (%) 28(5.8) 28.6(5.3) 29(5.4) 28.8(5.4) Body mass index (kg/m2) 19.4(3.1) 19.4(3) 19.8(3.1) 19.4(3) Fat mass index (kg/m2) 5.7(1.9) 5.9(2) 6.2(2.1) 6(2.1) Table 2: Comparison between obesity status based on Body Mass Index (BMI≥95% CDC2000) and Fat Mass Index (FMI ≥ 90% reference data) in subjects Obesity based on FMI Obesity based on BMI FMI ≥ 90% FMI <90% Total BMI≥95% 59(57.3)* 5(1.6) 64(15.6) BMI<95% 44(42.7) 302(98.4)** 346(84.4) Total 103(25) 307(75) 410(100) χ2 test was applied *sensitivity of BMI, P< 0.05 **specificity of BMI, P< 0.05 |
| نتیجه مقاله | Mean and SD BMI and FMI in children was 19.4 ± 3(kg/m2) and 6 ± 2.1(kg/m2) respectively. The area under the ROC curve 83% was calculated and the sensitivity and specificity and cut-off point of BMI compared with FMI was calculated 21.2 kg/m2 and 59 percent and 97 percent. The agreement between BMI = 21.2 kg/m2 and FMI= 6.9 kg/m2 in determine obesity was 0.5. In this study the BMI sensitivity was poor and only 59% of the children who were obese based on FMI, were also obese based on BMI and 3% of the children, who were identified as non-obese based on FMI, were obese based BMI. FMI seems more accurate measure of obesity than BMI is, however, more research is needed in this area. |
| نام فایل | تاریخ درج فایل | اندازه فایل | دانلود |
|---|---|---|---|
| FMI.pdf | 1397/01/26 | 259167 | دانلود |
| fmi.jpg | 1397/01/26 | 227445 | دانلود |
| invitation letter spain.pdf | 1397/01/26 | 272023 | دانلود |
