ISSN: 2165-7904
Journal of Obesity & Weight Loss Therapy
Make the best use of Scientific Research and information from our 700+ peer reviewed, Open Access Journals that operates with the help of 50,000+ Editorial Board Members and esteemed reviewers and 1000+ Scientific associations in Medical, Clinical, Pharmaceutical, Engineering, Technology and Management Fields.
Meet Inspiring Speakers and Experts at our 3000+ Global Conferenceseries Events with over 600+ Conferences, 1200+ Symposiums and 1200+ Workshops on Medical, Pharma, Engineering, Science, Technology and Business
Short Communication Open Access
Validity of Newly Developed BMI and Waist Cutoff Values for Sri Lankan Children
| Pujitha Wickramasinghe* | |
| Department of Paediatrics, University of Colombo, Srilanka | |
| Corresponding Author : | Pujitha Wickramasinghe Senior Lecturer in Paediatrics Department of Paediatrics University of Colombo, Srilanka Tel: +94 11 466 5500 Fax: +94 11 466 5544 E-mail:pujithaw@yahoo.com |
| Received: October 27, 2015; Accepted:November 23, 2015; Published: November 26, 2015 | |
| Citation: Wickramasinghe P (2015) Validity of Newly Developed BMI and Waist Cutoff Values for Sri Lankan Children. J Obes Weight Loss Ther 5:282. doi:10.4172/2165-7904.1000282 | |
| Copyright:© 2015 Wickramasinghe P. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited. |
|
| Related article at Pubmed, Scholar Google | |
Visit for more related articles at Journal of Obesity & Weight Loss Therapy
| Background |
| Childhood obesity is increasing in epidemic proportions worldwide. Morbidity related to obesity is associated with the degree of body fat mass (FM) and direct measurement of it would be the best way making the diagnosis. However, due to practical difficulties surrogate markers have been used and most popular are the BMI and waist circumference (WC). Although none of them are specific, they could be used to obtain a reasonable assessment. However, the reliability of these measures depends to a greater extend on the cutoff values used. International cutoffs are mainly based on white Caucasian studies and its usefulness in other ethnic groups are doubtful. There is a clear ethnic differences in body composition, where Asian populations have more fat in the body to any given BMI compared to white Caucasian populations. Because of that even WHO has suggested to have lower BMI cutoff values for Asian populations while IDF has used a lower waist circumference cutoff to diagnose metabolic syndrome in Asian populations. Although there is no universal consensus in drawing up of ethnic/population specific anthropometric cutoff values, in the published literature there are cutoff values derived for such groups for both adults and children. It is interesting to assess the suitability of newly developed Sri Lankan anthropometric cutoff values in the diagnosis of obesity in Sri Lankan children. |
| A set of BMI and WC cutoffs for Sri Lankan children were published by Wickramasinghe et al. [1] and its usefulness in diagnosing obesity in a group of 5-15 year old Sri Lankan children was compared with other available cutoffs (IOTF, WHO, British and CDC BMI and British WC). |
| In the assessment of 920 children FM showed significant associations with BMI(r=0.92, p<0.001), WC(r=0.90, p<0.001). Based on %FM cut offs, 22.5% girls and 18.5% boys were obese. All international anthropometric cutoff values underestimated obesity. However, Sri Lankan WC and BMI cutoff values over-estimated the diagnosis. International BMI and WC based cutoff values had high specificity but a low sensitivity while Sri Lankan BMI and WC cutoff values had high sensitivity but low specificity. It is clear that internationally available BMI and WC cutoff values underestimate the problem of obesity in Sri Lankan children. Locally developed BMI and WC cutoff values are more sensitive in detecting cases of obesity. Consensus should be developed to improve the screening/diagnosis of obesity in children of Asian populations. |
| Introduction |
| The dawn of the twenty first century has seen a considerable change in the nutritional status and disease pattern all over the world. Obesity has taken the place of under-nutrition that dominated previous century. Non communicable disease (NCD) burden has increased which is directly related to the obesity epidemic. Obesity, by definition is accumulation of excess body fat in the body that is associated with morbidity [2]. Therefore diagnosis of obesity should be ideally based on absolute body FM measurements. However, due to practical difficulties different surrogate measures have been used and BMI had been the most prevalent while WC had been gaining importance due to its direct association with metabolic risks. Fat content of the body vary between populations/ethnic groups, where for any given BMI value south Asian populations have a very high body FM, thus using the conventionally accepted 25kgm-2 and 30kgm-2 for over weight and obesity respectively will lead to under detection of many obese individuals in the Asian region. This made WHO to consider that BMI cut offs should be low as 22-25 kgm-2 [3] for adults. Similarly the WC cutoff values are also low in Asian populations compared to white Caucasians [4] In children BMI and WC changes with age and sex, therefore a single cutoff value cannot be used. BMI for age charts were developed by different bodies (WHO 2007; CDC/NCHS 2000; British Growth Foundation 1990). The International Obesity Task Force (IOTF) developed age and sex specific cut-off values to diagnose both overweight and obesity from 2 years to 18 years at half yearly intervals [5]. All these cut-off values are based on population distribution of an anthropometric parameter rather than on a biological end point and the prevalence of obesity will depend on the centile/Z score charts and their cutoff values used. Because of this the prevalence of obesity could vary depending on the cutoff value used [6]. Most of these studies showed that IOTF cutoffs had the lowest prevalence while CDC gave the highest prevalence [7,8]. |
| Therefore in multiethnic communities, diagnosis of childhood obesity, using a universal definition had been unsuccessful [9]. This has resulted in a debate as to whether ethnicity-specific [10] or populationspecific [11] BMI cut off values should be used. |
| WC is more closely related to insulin resistance and associated metabolic abnormalities. WC is used as an absolute criterion in the diagnosis of metabolic syndrome, by IDF. WC has shown to have a strong association with metabolic derangements in obese Sri Lankan children than BMI [12]. |
| A limited number of studies have looked at the FM that is associated with adverse metabolic outcomes and most are in non- Asian populations. Few studies have identified the percentage FM associated with metabolic risk to range between 30-35% in girls and 20-25% in boys [13-15] International cutoff values have shown a very low sensitivity in detecting obesity among Australian children of white Caucasian and Sri Lankan origins [16]. Once again the IOTF cutoffs showed the lowest sensitivity. In view of this, in 2011, a new set of BMI and WC based cut off values were developed to diagnose obesity among Sri Lanka children [17]. Rather than using the population distribution of the two parameters, percentage FM s associated with metabolic risk and developed based on regression models. They were based on a %FM of 35% for girls and 25% for boys [18].Validated and compare these cutoff values with existing international cutoff values in an independent group of Sri Lankan children. |
| Subjects |
| A cross-sectional descriptive study had been carried out among 920, 5-15-year-old apparently healthy Sri Lankan children selected randomly from schools in the district of Colombo, Sri Lanka. Validity and accuracy of the indicators were evaluated by calculating sensitivity, specificity, positive predictive value and efficiency, relative to true obesity diagnosed by absolute %FM based on Bioelectrical Impedance Assay (BIA) technique. Results |
| Boys to girls ration of the group was 547/373. Correlation of BMI and WC with FM was stronger compared to the relationship of BMI and WC with %FM. Anthropometric measures had a significant stronger association with FM than with %FM. |
| Based on percentage FM 22.8% girls and 18.5% of boys were obese. The IOTF BMI based cutoff detected only 4.8% girls and 2.5% boys as obese. The proportions of obese children detected by WHO and British growth standards were little higher than the proportion detected by IOTF cutoff values. International WC measures were able to diagnose more cases of obesity than BMI based cutoff values. The newly developed Sri Lankan BMI standards detected 26.3% girls and 19.0% boys as obese. Both Sri Lankan BMI and WC cutoff values over estimated the obese cases. |
| BMI based international cutoff, in both girls and boys had a very low sensitivity ranging from 11.9 to 32.9%, but high specificity (>98.6%). The positive predictive value was more than 84% and efficiency was also high ranging between 79.9-86.7% in both groups. Diagnosis of obesity based on international WC cutoff demonstrated better sensitivity (84.7-93.1 %) with slightly low specificity (88.1-97.3%) compared to BMI. |
| The Sri Lankan based BMI cutoff values had higher sensitivity in detecting obese patients compared to the available IOTF cutoff values in both gender groups. Although the specificity was lower than the other BMI based cutoff values, it was more than 90% in both gender groups. The positive predictive value was low but the efficiency was better than other BMI based cutoff values. Although the specificity was low the Sri Lanka based WC (79.7-82.3%) cutoff values had higher sensitivity (93.1-95.3%) and was better than all tested obesity diagnostic tools when screening for obesity in Sri Lankan children. Furthermore the efficiency was equal to other methods. |
| Discussion |
| Childhood body composition is directly responsible for the onset of non-communicable diseases. Fatness in childhood and adolescence persists into adulthood and the adverse metabolic profiles show a cumulative effect. Therefore when fat accumulation begins from a younger age, adverse outcomes would show early onset. Although, there is still no consensus developed on the exact percentage body fat that could be linked to adverse metabolic profiles, a %FM of about 25% in male and 35% in girls could be considered as reasonable cutoff. |
| Ideally, obesity should be diagnosed and followed up based on the absolute fat measurement of body. However, as this is not practical in field settings, BMI is used as a surrogate measure. BMI, which is a ratio between weight and height, does not always reflect the percentage body fat accurately. Furthermore as BMI does not distinguish between different components of the body, as well as it cannot quantify the FM of the body. |
| Similarly there are many other studies that have shown that internationally agreed cutoff does not provide satisfactory results. In New Zealand detection of obesity in children of Indian and Pacific Island origin was low [16]. Similarly the IOTF showed poor sensitivity in diagnosing obesity in Swedish adolescence, improved by the use of country specific charts [17]. Therefore lowering cutoff value is one option, such as using overweight cutoff values to detect obesity, but still they are not specific to a population/ethic group thus not provides the correct solution. |
| As much as it has shown by many other studies, obesity prevalence is low in this group of Sri Lankan children when available international BMI cutoff values were used. This underestimation of the problem could delay detection of cases as well as the danger of policy makers overlooking the problem would have many long term adverse health and economic outcome for individuals as well as for a country. Although the Sri Lankan cutoffs had high sensitivity, as authors have argued, it could lower the threshold of detecting obese children. Furthermore such detections would lead only to be aware of the increased risk and impart a positive health. Specific managements of obesity depends on specific complications rather than the simple state of excess fat. Therefore over diagnosis of obesity with no metabolic complications will not cost the health system additional resources but will provide some benefits through preventions of developing complications. |
| There had been a long cry for population specific cutoff values. As WHO (2000) also has acknowledge the need for lower BMI cutoff values for Asians, a feasible option would be either to revise BMI cutoff values to suit a population/ethnic groups or use methods to assess the absolute body content of body. |
| Waist circumference is an easy measure and reflects abdominal obesity which is directly related to the adverse metabolic consequences better than BMI. WC in this study showed a higher sensitivity but low specificity compared to BMI. Its high sensitivity could lead to over diagnosis of the issue leading to panic as well as strain on the health system. However as authors point out such over detection would increase awareness of the condition and would have a buffer zone for people to take preventive action much early. |
| The %FM associated with morbidity defined in this study is what has been set for western populations. The body fat content that would be associated with morbidity in Sri Lankan children have been evaluated recently where the percentage FM associated with adverse metabolic profile in males is 28% and in girls it is 32% [15]. Therefore it clearly shows that the fat percentage associated with adverse health outcomes is more or less similar in all populations but due to changes in the body composition distribution, the BMI and WC reflecting the FM differs. |
| The weak association shown between BMI and %FM cast doubt over used of BMI/WC as surrogate a markers of body FM. However, its simplicity to use in the community and reproducibility makes it the most prudent screening tool for obesity. However, as far as children are concerned, there is no universal agreement on the use of cutoff value, whether centile based or Z score based or absolute values. Furthermore, cutoff values whether internationally available or country specific or ethnic specific in multiethnic populations needs more research. This study highlights that best would be to use BMI and WC as screening tools and have more objective measures such as BIA to evaluate the absolute fat content of body for the diagnosis and management of obesity in Sri Lankan children |
References
- Wickramasinghe VP, Arambepola C, Bandara P, Abeysekera M, Kuruppu S, et al. (2013a) Validity of newly developed BMI cut-off values for Sri Lankan children. Annals of Human Biology 40:280-5.
- WHO Technical Report Series-894 (2000) Obesity: Preventing and managing the global epidemic. WHO, Geneva
- WHO expert consultation (2004) Appropriate body-mass index for Asian populations and itsimplications for policy and intervention strategies. Lancet363: 157–63
- Flegal KM, Ogden CL, Wei R, Kuczmarski RL, Johnson CL(2001)Prevalence of overweight in US children: comparison of US growth charts from the centers for disease control and prevention with other reference values for body mass index. Am J Clin Nutr 73:1086-1093.
- LangIA, Kipping RR, Jago R, Lawlor DA (2011) Variation in childhood and adolescent obesity prevalence defined by international and country-specific criteria in England and the United States. Eur J Clin Nutr 65:143-50
- Rush EC, Puniani K, Valencia ME, Davies PS, Plank LD (2003) Estimation of body fatness from body mass index and bioelectrical impedance: comparison of New Zealand European, Maori and Pacific Island children. EurJ Clin Nutr 57:1394-1401.
- Misra A (2003) Revisions of cut offs of body mass index to define overweight and obesity are needed for the Asian-ethnic groups. Int J Obes 27:1294-1296.
- Stevens J (2003) Ethnic-specific revisions of body mass index cut-offs to define over weight and obesity in Asians are not warranted. Int J Obes 27:1297-1299.
- De Silva KSH, Wickramasinghe VP, Goonerathne INA (2006) Metabolic consequences of childhood obesity – a preliminary report. CMJ51:105-109.
- Dwyer T, Blizzard CL (1996) Defining obesity in children by biological endpoint rather than population distribution. Int J Obes Relat Metab Disord20:472-480
- Williams DP, Going SB, Lohman TG (1992) Body fatness and risk for elevated blood pressure, total cholesterol and serum lipoprotein ratios in children and adolescents. Am J Pub Health 82: 358-363
- Lohman TG (1992) the prevalence of obesity in children in the United States. In Advances in body composition assessment. Human Kinetics, Champaign, IL.Monogram3:79-89.
- Wickramasinghe VP, Cleghorn GJ, Edmiston KA, Murphy AJ, Abbott RA et al. (2005) Validity of BMI as a measure of obesity in Australian white Caucasian and Australian Sri Lankan children. Ann Hum Biol 32:60-72.
- Wickramasinghe VP, Lamabadusuriya SP, Cleghorn GJ, Davies PSW (2011) Defining Anthropometric cut-off levels related to metabolic risk in a group of Sri Lankan children. Ann Hum Biol 38:537-43.
- Wickramasinghe VP, Arambepola C, Bandara P, Abeysekera M, Kuruppu S et al. (2013b) Defining Obesity Using Biological End Point in Children. 20th ICN, Granda, Spain. Oral Paper (O102) Annals of Nutrition and Metabolism 63:208.
- Duncan JS, Schofield G, Duncan EK, Rush EC (2005) Classifying childhood obesity in a multiethnic population: comparisons among five major ethnic groups. O27 Abstract. International Journal of Body Composition Research 3:89.
- Neovius MG, Linné YM, Barkeling BS, Rossner SO (2004)Sensitivity and specificity of classification systems for fatness in adolescents. Am J Clin Nutr 80:597-603.
Relevant Topics
- Android Obesity
- Anti Obesity Medication
- Bariatric Surgery
- Best Ways to Lose Weight
- Body Mass Index (BMI)
- Child Obesity Statistics
- Comorbidities of Obesity
- Diabetes and Obesity
- Diabetic Diet
- Diet
- Etiology of Obesity
- Exogenous Obesity
- Fat Burning Foods
- Gastric By-pass Surgery
- Genetics of Obesity
- Global Obesity Statistics
- Gynoid Obesity
- Junk Food and Childhood Obesity
- Obesity
- Obesity and Cancer
- Obesity and Nutrition
- Obesity and Sleep Apnea
- Obesity Complications
- Obesity in Pregnancy
- Obesity in United States
- Visceral Obesity
- Weight Loss
- Weight Loss Clinics
- Weight Loss Supplements
- Weight Management Programs
Recommended Journals
Article Tools
Article Usage
- Total views: 9969
- [From(publication date):
December-2015 - Sep 21, 2024] - Breakdown by view type
- HTML page views : 9287
- PDF downloads : 682
