https://imcjms.com Ibrahim Medical College Journal of Medical Science https://imcjms.com/registration/journal_full_text/191 Thu, 20 Apr 2017 09:51:10 +0000 Anthropometric indicators of abdominal obesity are associated with cardiovascular risk factors, such as type 2 diabetes, hypertension, and dyslipidemia. Controversy remains regarding the best anthropometric indices for cardiovascular risk. Waist-to-height ratio has been reported to be an effective predictor of metabolic risks and it may be a better measure of relative fat distribution amongst subjects of different age and statures. Bangladeshi data lack in this perspective. To determine waist-to-height ratio of Bangladeshi adults along with its variation with socio-economic status, cross-sectional studies were conducted in 2002 and 2003. Data were collected through interviewing and measuring height and waist circumference of 22,995 adult males and females of an urban (Mirpur, Dhaka City) and rural area (Kaliganj sub-district). The mean waist-to-height ratio of 0.48 significantly varied with socio-demographic variables and it was markedly higher in females, older age groups, urban residents and the better educated. Urban residents, females, older people, better educational status, the non-paid and married individuals were more likely to have high waist-to-height ratio (³0.5). High waist-to-height ratio levels using sex-specific cut-offs were more common in females, urban residents, Christians, older individuals, married, the better educated and the non-paid. Age and locality were identified as best predictors in males and females, respectively. Address for Correspondence:Dr. Meerjady Sabrina Flora, Associate Professor of Epidemiology, National Institute of Preventive and Social Medicine, Mohakhali, Dhaka, Bangladesh. e-mail: meerflora@yahoo.com   Bangladesh is having a double burden of health problems; the occurrence of non-communicable diseases is also increasing in addition to existence and emergence of infectious diseases. Moreover, it faces nutrition transition with over-nutrition and under-nutrition occurring simultaneously. While about a quarter of rural, and lower class urban people have chronic energy deficiency; the prevalence of obesity in the upper and middle class urban people is between 9-11%.1 It is being increasingly recognised that central, rather than general obesity, is likely to coexist with type 2 diabetes and lead to complications including cardiovascular diseases. Although its importance is acknowledged, no unified definition exists for central obesity; several anthropometric indexes such as waist circumference (WC), waist-hip ratio (WHR), waist-to-height ratio (WHtR), conicity index (Cindex) etc, are being used.2 These anthropometric indices are associated with cardiovascular risk factors, such as type 2 diabetes, hypertension, and dyslipidemia. However, controversy remains regarding the best anthropometric indices for cardiovascular disease (CVD) risk.3 WC was the main variable used as a measure of central obesity as it is much simpler and more practical to use and because it associates more strongly with cardio-vascular diseases and is a better predictor of future risk of metabolic diseases.4 However, WC measurement has been criticized for not taking into account differences in body height, and the WHtR value is a better predictor of cardiovascular risk factors.3 The ratio of waist circumference to height may be a superior measure for women as well as men5 and a simple index for measuring coronary risk. Waist circumference reflects abdominal obesity, and height is relatively constant in adults and can be used to compensate for variations in frame size.6 WHtR has been reported to be an effective predictor of metabolic risks and it may be a better measure of relative fat distribution amongst subjects of different age and statures.7 The index, especially for women, is a better indicator for predicting obesity-related CVD risk factors than other indices.8 Collection of good quality national data on different indicators of central obesity is needed. So far data available in this regard, are mostly on WC and WHR. In an earlier publication of this study the Cindex of Bangladeshi population is described.9 The current attempt is to explore WHtR. A small scale study, which was done on rural adults only, provide mean WHtR data of adult male (0.43 ± 0.04) and female (0.44 ± 0.05) Bangladeshi.10 Therefore, the current study attempted to find out the WHtR of rural as well as urban adults from a large sample. Materials and methods Subjects were measured wearing minimal attire. All the equipment was checked regularly to minimise random errors. Height was measured to the nearest 0.1 cm with a specially constructed wooden height stand to which a plastic measuring tape was attached. The subject stood without shoes or head gear (cap, ribbon etc) in an upright posture with their head in the Frankfurt plane. Subjects were asked to keep their heels close together with their hands hanging freely by their side, palms facing inwards. The horizontal blade of the stadiometer was gently placed on the crown of the head to take the measurement. A flexible plastic tape was used to measure waist circumference, accurate up to the nearest 0.1cm. Waist circumference was measured at the level mid way between the lowest rib margin and the superior iliac crest on the mid-axillary line in a horizontal plane. The subjects stood erect with abdomen relaxed, the arms at the side and feet together and breathing normally.   The mean (SD) waist-to-height ratio was 0.48 (0.07), but there was considerable variation in relation to socio-demographic status (Table 1). Age showed a curvilinear association (3rd order polynomial) with WHtR; WHtR gradually increased with age, ending in a plateau in the 40-69 age group and falling slightly in the 70+ group; after correcting for sex the trend was more pronounced with greater increments between each age group. Females had higher WHtR than males, before and after, controlling for age effects. Urban residents had, on average, a higher WHtR while Hindus, unmarried individuals and manual labourers had, on average, a lower WHtR. There was a general upward trend in mean WHtR with improvement in educational status. Table 1: Waist-to-Height Ratio in Relation to the Socio-demographic Variables   Waist-to-height ratio was categorised as normal and high based on a cut-off of 0.5 for both sexes. Overall 32% of the sample were found in the high category although the percentages varied widely by socio-demographic variable (Table 2). Females and urban residents were almost twice more likely to have high WHtR. The proportion of high WHtR increased with age up to 40-49 years, then gradually decreased with advancing age. The proportion also increased with educational attainment. Manual labourers, unmarried individuals and Hindus were less likely to have a high WHtR. Table 2: Wais- to-Height Ratio Categories Using a Common Cut-off (both sex) in Relation to the Socio-demographic Variables       WHtR was also categorised using sex-specific cut-offs (male 0.48 and female 0.45) and half of the sample were found to have high WHtR. Considerable heterogeneity was observed in the WHtR categories in relation to the socio-demographic variables (Table 4). Females, urban residents, the better educated, older individuals, widows/divorcees, the non-paid and Christians were more likely to have a high WHtR. Table 4: Waist-to-Height Ratio Categories Using Sex-specific Cut-offs in Relation to the Socio-demographic Variables     Table 6: Comparison of Mean BMI, WC, WHtR and Cindex between the Current and Other Asian Studies   Vague was the first to observe that women with android obesity had a high prevalence of diabetes and atherosclerosis.12 Subsequent studies have shown that abdominal obesity, as measured by the waist circumference or related indexes, is associated with the subsequent development of type 2 diabetes13-16 and ischemic heart disease17-19 as well as with risk factors for CVD.20 The advantages of WHtR were listed by Hsieh et al. (2003): “(1) closer agreement of values between men and women at all ages; (2) more accurate tracking of fat distribution and accumulation by age; (3) closer correlation with morbidity index for coronary risk factors; (4) more comprehensive identification of overweight individuals and those of normal weight facing higher risks (5) greater simplicity, in that a single rule (keep your waist circumference below half your height) may be applied both for men and women, enabling busy physicians and other professionals to screen and counsel examinees who face higher metabolic risks during physical examinations”. In this way, the index can serve as a ‘second stethoscope’.25 Adult anthropometric data in Bangladesh cover weight and BMI and most nutrition research has focused on under-nutrition, particularly among women and children. BMI does not give any indication of the distribution of weight in the body. Anthropometric indicators of abdominal obesity estimate the amount of visceral fat tissue which, in turn, is associated with a higher risk of development of cardiovascular diseases. So, waist circumference, waist–to-height ratio as well as conicity index were also used in order to provide some notion of central obesity. However, WC, a much studied indicator and Cindex did not show high predictive accuracy. The current study focused on this important but relatively less used indicator. The overall mean WHtR in the current study was 0.48 mean which is comparable with other Asian studies as shown in Table 6 with mean values in the current study within the Asian range. The average WHtR was higher in females suggesting consistency with the findings of Sayeed et al.10 The overall WHtR seems higher than the previous Bangladeshi data because that study was done in rural samples which were lower than urban residents. The current study supports this idea showing higher WHtR in urban residents. Overall 19% of the variation in WHtR were explained by socio-demographic variables, and the main predictors were locality, age, and education. The current study used both Japanese7 and Taiwanese8 cut-offs to detect high WHtR. About 32% and half of the samples respectively were identified as high WHtR using cut-off of 0.5 for both sex and sex-specific cut-off. Urban residents, females, older people, better educational status, the non-paid were more likely to have a high WHtR. Occupation followed by locality (for WHtR ³0.5) and sex followed by age (for WHtR ³0.48 for men and ³0.45 for women) were the best predictors. Age and locality were identified as best predictors in males and females, respectively. No such data were available to compare with.   The authors are grateful to the Department for International Development (DFID), United Kingdom, Board of Graduate Studies, the University of Cambridge, The British Federation of Women Graduates Charitable Foundation, The Charles Wallace Bangladesh Trust, and Churchill College, the University of Cambridge for their support. References 2.   Mamtani MR & Kulkarni HR. Predictive performance of anthropometric indexes of central obesity for the risk of type 2 Diabetes. Arch Med Res 2005; 36: 581-589. 4.   Ford ES, Mokdad AH & Giles WH. Trends in waist circumference among US adults. Obes Res 2003; 11: 1223-1231. 6.   Hsieh SD & Yoshinaga H. Waist/Height ratio as a simple and useful predictor of coronary heart disease risk factors in women. Int Med 1995; 34: 1147-1152. 8.   Lin WY, Lee LT, Chen CY, Lo H, Hsia HH, Liu IL et al. Optimal cut-off values for obesity: using simple anthropometric indices to predict cardiovascular risk in taiwan. 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Adiposity indices and their relationship with some risk factors of coronary heart disease in middle-aged Cambridge men and women. Ann Hum Biol 2000; 27: 239-248. 28.Pitanga FJG & Lessa I. Sensitivity and specificity of the conicity index as a coronary risk predictor among adults in salvador, Brazil. Rev Bras Epidemiol 2004; 7: 259-269. 30.Ko GTC, Chan JCN, Cockram CS & Woo J. Prediction of hypertension, diabetes, dyslipidaemia or albuminuria using simple anthropometric indexes in Hong Kong Chinese. Int J Obes 1999; 23: 1136-1142. 2026 Ibrahim Medical College. All rights reserved.