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 date: Oct 27, 2015; Accepted date: Nov 23, 2015; Published date: Nov 26, 2015 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. 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. ere 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 e 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]. erefore 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 overweight and obesity respectively will lead to under detection of many obese individuals in the Asian region. is 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). e 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]. erefore in multiethnic communities, diagnosis of childhood obesity, using a universal definition had been unsuccessful [9]. is has resulted in a debate as to whether ethnicity-specific [10] or population- specific [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 Wickramasinghe, J Obes Weight Loss Ther 2015, 5:6 http://dx.doi.org/10.4172/2165-7904.1000282 Short Communication Open Access J Obes Weight Loss er ISSN:2165-7904 JOWT, an open access journal Volume 5 • Issue 6 • 1000282 Journal of Obesity & Weight Loss Therapy J o u r n a l o f O b e s i t y & W e i g h t L o s s T h e r a p y