Body mass index: Is it relevant for Indians?
 

Body mass index: Is it relevant for Indians?

on

  • 58 views

Obesity is defined as excessive unhealthy accumulation of body fat. India has the third largest obese population in the world after United States of America and China. Prevalence of obesity has ...

Obesity is defined as excessive unhealthy accumulation of body fat. India has the third largest obese population in the world after United States of America and China. Prevalence of obesity has reached epidemic proportions in parts of India. In some urban areas, up to a third of the population is either overweight or obese. Childhood and adolescent obesity is also rising rapidly. If this trend continues, certain sections of Indian society may start seeing declining life expectancy in India after many decades of steady progress. Early diagnosis of overweight and obesity may prevent progression to more severe forms associated with complications. In this review, we examine the usefulness of Body Mass Index in diagnosis of obesity in Asian Indian population and the debate surrounding the call for a downward revision of “normal” range in this population.

Statistics

Views

Total Views
58
Views on SlideShare
58
Embed Views
0

Actions

Likes
0
Downloads
0
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Body mass index: Is it relevant for Indians? Body mass index: Is it relevant for Indians? Document Transcript

  •                                                                                                   B                                      Body mas        ss index: IIs it relev      vant for Inndians?
  • Review Article Body mass index: Is it relevant for Indians? Kamal K. Mahawar a,b,* a Senior Consultant, Bariatric & Metabolic Surgery, Apollo Obesity and Metabolic Surgery Centre, Indraprastha Apollo Hospital, New Delhi, India b Honorary Consultant Surgeon, Sunderland Royal Hospital, Sunderland SR4 7TP, United Kingdom a r t i c l e i n f o Article history: Received 25 June 2014 Accepted 26 July 2014 Available online xxx Keywords: Obesity Body mass index Body fat content a b s t r a c t Obesity is defined as excessive unhealthy accumulation of body fat. India has the third largest obese population in the world after United States of America and China. Prevalence of obesity has reached epidemic proportions in parts of India. In some urban areas, up to a third of the population is either overweight or obese. Childhood and adolescent obesity is also rising rapidly. If this trend continues, certain sections of Indian society may start seeing declining life expectancy in India after many decades of steady progress. Early diagnosis of overweight and obesity may prevent progression to more severe forms asso- ciated with complications. In this review, we examine the usefulness of Body Mass Index in diagnosis of obesity in Asian Indian population and the debate surrounding the call for a downward revision of “normal” range in this population. Copyright © 2014, Indraprastha Medical Corporation Ltd. All rights reserved. 1. Background Obesity or excessive body fat is associated with poor cardio- vascular and general health outcomes.1 Accurate identifica- tion of individuals with an abnormal level of body fat or adiposity can be challenging, as sophisticated tools for body fat analysis are not widely available outside specialist obesity clinics. Body Weight and Body Mass Index (BMI) are the most commonly used population level surrogate tools to measure an individual's adiposity. This relationship between adiposity and BMI is far from a direct correlation and can vary depending on age (older population has more body fat), sex (women have more body fat), higher muscle and bone mass (athletes have less body fat), abdominal obesity (Indian population), body fat percentage (Indians have higher body fat percentage) etc.1e3 Currently accepted World Health Organization guidelines indicate that BMI range of 18.5 kg/m2 e24.99 kg/m2 is normal. Those with a BMI 25.0 kg/m2 to 29.99 kg/m2 are considered as overweight and obesity is defined as a BMI of 30.0 kg/m2 [Z]. Several recent studies have however examined continued relevance of the BMI range between 18.5 kg/m2 e25.0 kg/m2 as the normal range for the global population. High body fat is an independent predictor of all cause mortality4 and since In- dians have more body fat at any given BMI, there has been a call for downward revision of normal BMI range for Indians.5,6 Furthermore, Indians are more susceptible to the riskier abdominal (visceral) fat,5,7,8 which is independently associ- ated with diabetes mellitus,9 metabolic syndrome, and Abbreviations: BMI, Body Mass Index. * Apollo Obesity and Metabolic Surgery Centre, Indraprastha Apollo Hospital, New Delhi, India. E-mail address: kamal_mahawar@hotmail.com. Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/apme a p o l l o m e d i c i n e x x x ( 2 0 1 4 ) 1 e4 Please cite this article in press as: Mahawar KK, Body mass index: Is it relevant for Indians?, Apollo Medicine (2014), http:// dx.doi.org/10.1016/j.apme.2014.07.013 http://dx.doi.org/10.1016/j.apme.2014.07.013 0976-0016/Copyright © 2014, Indraprastha Medical Corporation Ltd. All rights reserved.
  • cardiovascular disease. BMI is a poor indicator of visceral adiposity. We examine the literature surrounding the usefulness of BMI in identifying population at risk of developing adverse health consequences as a result of obesity in India in this review. 2. BMI and mortality Ideal BMI that results in best health outcomes has been a matter of considerable debate amongst academicians. Several recent studies have studied correlation between BMI and mortality.10e15 Though most studies examining relationship between BMI and mortality have found lowest mortality amongst people with BMI <25 kg/m2 , some13e15 have found overweight (BMI 25 kg/m2 e29.9 kg/m2 ) to be associated with lowest mortality. These studies are usually pooled analysis of a large number of studies, with very different subject as well as study characteristics. It is important to understand the limi- tations of conclusions derived from pooling of such data. These studies usually generate a lot of hype in media due to the sheer numbers involved, even though the quality of scientific data in such pooled analysis of cohort studies is understandably weak. A recent collaborative analysis10 of baseline BMI versus mortality in 57 prospective studies with 894,576 participants (mostly from western Europe and North America) revealed that the mortality rate was lowest in both sexes in the BMI range of 22.5 kg/m2 e25.0 kg/m2 and increased proportionately with any further rise in BMI. Each 5 kg/m2 higher BMI led to about 30% higher overall mortality. According to this study, moderate obesity (BMI 30.0 kg/m2 e35 kg/m2 ) reduced life ex- pectancy by about 2e4 years and severe obesity (BMI 40.0 kg/ m2 e45.0 kg/m2 ) shortened a person's life by 8e10 years. Interestingly in this study, the mean BMI was slightly lower in current smokers than in never-smokers (male 0$3 kg/m2 , fe- male 0$9 kg/m2 lower), and in regular alcohol users than in others (male 0$1 kg/m2 , female 1$2 kg/m2 lower). Similar results were obtained by another study11 where mortality from any cause was lowest amongst white adults with a BMI of 22.5 kg/m2 e24.9 kg/m2 . However, the analysis for those who never smoked showed lowest death rates at a BMI of 20.0 kg/m2 e25.0 kg/m2 and showed an approximately linear relationship between BMI and mortality in the range of BMI 25.0 kg/m2 e40.0 kg/m2 . When the BMI was analyzed as a continuous variable, the hazard ratio for each 5-unit increase was 1.31 over the range of 25.0 kg/m2 e49.9 kg/m2 . Authors concluded that in white adults, overweight and obesity are associated with increased all cause mortality. Another study from Taiwan12 found lowest mortality in the group with BMI 22 kg/m2 e26 kg/m2 overall but in BMI 20 kg/m2 e22 kg/m2 ranges after excluding smokers and those with cancers. In contrast to above observations, Flegal et al13 rather controversially claimed last year in an article published in Journal of American Medical Association that overweight (BMI 25 kg/m2 e30 kg/m2 ) was associated with significantly lower all cause mortality relative to normal weight. In this study though class 2 and 3 obesity was associated with significantly higher all-cause mortality; class 1 obesity was not and over- weight was in fact protective. It is worth knowing that many of these studies fail to satisfactorily account for confounding variables that are independently associated with both BMI and early mortality. The importance of variables like baseline age, female sex, pre- existing chronic disease, urban residence, higher education, higher socioeconomic class, better living conditions, better nutrition, smoking, and significant alcohol consumption in analyzing relationship between BMI and mortality, is now widely appreciated.16,17 Lack of proper adjustment for one or more of these confounding variables may have accounted for the superior health outcomes seen in overweight patients (BMI 25.0 kg/m2 e29.9 kg/m2 ) in some of these studies. Other explanations for such counterintuitive beneficial effects of being overweight may be earlier presentation of obese pa- tients, higher likelihood of receiving medical treatment, cardio-protective metabolic effects of increased body fat, and benefits of higher metabolic reserves.13 In Indian context, overweight and obesity are diseases of the affluent in the society, who can afford better education and healthcare, which their poorer counterparts with lower BMI cannot. For instance, Pednekar et al.18 observed from their large study of 148,173 men and women in Mumbai that over- weight men and women (BMI 25.0 kg/m2 e30.0 kg/m2 ) had lowest mortality. These findings are easy to explain when we find out that the study did not include upper middle class and upper class people and authors themselves conceded that the study cohort might not have been representative of Mumbai's population. Socioeconomic status is known to be a big con- founding factor in Indian studies.19,20 Lack of association be- tween BMI >23 kg/m2 and mortality seen in another large rural study from South Indian state of Kerala,21 could also be explained by lack of adjustment for socioeconomic status. The association between socioeconomic status and overweight is positive in most low and middle-income countries, as the burden of overweight and obesity has consistently remained concentrated amongst wealthier populations in these countries.22e24 3. Correlation between BMI, total body fat, and visceral fat Furthermore, limitations of BMI in reflecting total body fat content and abdominal obesity are widely recognized.16 This limitation is more pronounced at the lower BMI ranges and for certain population groups like Indians. BMI cannot differen- tiate between fat mass and muscle mass and it is now known that Asians have a higher body fat percentage for a given BMI.5,7,25 Rush et al.26 confirmed that Asian Indian men and women with a BMI of 24 and 26 respectively had the same percentage of body fat as Europeans with a BMI of 30 or Pacific men and women with a BMI of 34 and 35 respectively. Authors of this study concluded that Asian Indians have more total body fat, abdominal fat; and less lean mass, skeletal muscle mass, and bone mineral than all other ethnic groups.26 In another study of body fat content in North Indians, Dudeja et al.25 found that A BMI of 21.5 kg/m2 for males and 19.0 kg/m2 for females had the optimum sensitivity and specificity in identifying subjects with a high percentage of body fat. A number of other studies have also suggested that a BMI of a p o l l o m e d i c i n e x x x ( 2 0 1 4 ) 1 e42 Please cite this article in press as: Mahawar KK, Body mass index: Is it relevant for Indians?, Apollo Medicine (2014), http:// dx.doi.org/10.1016/j.apme.2014.07.013
  • <22.0 kg/m2 or <23.0 kg/m2 might be ideal for the Asian Indian population.7,27 Excessive body fat or adiposity is positively associated with cardiovascular disease. When one studies only cardiovascular disease related deaths amongst South Asians, unsurprisingly the lowest rate is seen in individuals with lowest adiposity, the ones in the BMI range of 15.0e19.9.17 Others have also said that the control of obesity and greater physical activity are the most effective strategies for prevention of diabetes and car- diovascular disease in South Asian people.28 Adiposity is more important than BMI in determining cardiovascular risk.17,29 This has led to call for wider use of body composition mea- sures to study the link between adiposity and mortality in future studies.30 Measuring total body fat is however not easy in routine clinical practice and tools to do that are beyond the reach of most clinicians, even in developed countries. There is hence an urgent need to invent tools for total body fat analysis that can be made available more widely. Some authors31 have further suggested that simply calculating body fat content is also unsatisfactory, as it does not take into account the vari- ations depending on the height of the individual. They have proposed calculation of a body fat mass index on the lines of body mass index, which incorporates the height of the indi- vidual as well. Indians are more predisposed to the abdominal or visceral adiposity and visceral adiposity is independently linked with diabetes mellitus and metabolic syndrome,5,28 and cardio- vascular risk.32,33 Not only do Asian Indians have higher upper-body adiposity and higher visceral fat for a given BMI when compared with the Western population, but also a tendency for minor changes in BMI to tilt the metabolic bal- ance towards hyperglycemia and metabolic syndrome.5,7,8 Risk of diabetes becomes significant at BMI >23 kg/m2 for urban Indians.7 In an earlier study, same authors had noted an increasing trend of diabetes with BMI >22 kg/m2 . Beyond CVD and type 2 diabetes, individuals with metabolic syndrome seemingly are susceptible to other conditions, notably poly- cystic ovary syndrome, fatty liver, cholesterol gallstones, asthma, sleep disturbances, and some forms of cancer.34 BMI has obvious limitations in measuring abdominal or visceral adiposity. Waist circumference can be used as a surrogate marker to measure abdominal obesity. It is indeed known people with large waist circumferences have excess burden of ill health.35 It is hence suggested that waist circumference and waist hip ratio may be better tools for measurement of abdominal obesity and should be measured more widely in Indian population. Relationship between BMI, Total Body Fat, and the riskier Visceral obesity is far from linear in Indian population. This is probably why WHO expert consultation36 in 2004 did not revise the cut-off points for overweight for Asian people. The consultation though agreed that a large number of Asian people have a high risk of type 2 diabetes and cardiovascular disease at BMIs lower than the existing WHO cut-off point for overweight (>or ¼ 25 kg/m2 ). They further observed that the cut-off points for increased risk varies from 22 kg/m2 to 25 kg/ m2 in different Asian populations and for high risk it varies from 26 kg/m2 to 31 kg/m2 . Even though the consultation did not recommend altering cut-off values, they did recommend further potential public health action points at BMIs of 23.0, 27.5, 32.5, and 37.5 kg/m2 . 4. Conclusion We feel there is a need to look beyond BMI when diagnosing pathological adiposity or obesity in Indian population. Waist Circumference and Waist Hip Ratio should be more widely used and where possible (in specialist clinics), total body fat content should be studied. Finally, one should take into ac- count individual's current health and genetic predisposition before deciding when to intervene. Conflicts of interest The author has none to declare. r e f e r e n c e s 1. Heitmann BL, Erikson H, Ellsinger BM, Mikkelsen KL, Larsson B. Mortality associated with body fat, fat-free mass and body mass index among 60-year-old swedish men-a 22- year follow-up. The study of men born in 1913. Int J Obes Relat Metab Disord. 2000;24(1):33e37. 2. Prentice AM, Jebb SA. Beyond body mass index. Obes Rev. 2001;2(3):141e147. 3. Pasco JA, Nicholson GC, Brennan SL, Kotowicz MA. Prevalence of obesity and the relationship between the body mass index and body fat: cross-sectional, population-based data. PLoS One. 2012;7(1):e29580. 4. Bigaard J, Frederiksen K, Tjønneland A, et al. Body fat and fat- free mass and all-cause mortality. Obes Res. 2004 Jul;12(7):1042e1049. 5. Banerji MA, Faridi N, Atluri R, Chaiken RL, Lebovitz HE. Body composition, visceral fat, leptin, and insulin resistance in Asian Indian men. J Clin Endocrinol Metab. 1999;84(1):137e144. 6. James WP, Chunming C, Inoue S. Appropriate Asian body mass indices? Obes Rev. 2002;3(3):139. 7. Snehalatha C, Viswanathan V, Ramachandran A. Cutoff values for normal anthropometric variables in Asian Indian adults. Diabetes Care. 2003;26(5):1380e1384. 8. Chandalia M, Abate N, Garg A, Stray-Gundersen J, Grundy SM. Relationship between generalized and upper body obesity to insulin resistance in Asian Indian men. J Clin Endocrinol Metab. 1999;84(7):2329e2335. 9. Kanaya AM, Wassel CL, Mathur D, et al. Prevalence and correlates of diabetes in South Asian Indians in the United States: findings from the metabolic syndrome and atherosclerosis in South Asians living in America study and the multi-ethnic study of atherosclerosis. Metab Syndr Relat Disord. 2010;8(2):157e164. 10. Prospective Studies Collaboration. Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies. Lancet. 2009;373:1083e1096. 11. Berrington de Gonzalez A, Hartge P, Cerhan JR, et al. Body- mass index and mortality among 1.46 million white adults. N Engl J Med. 2010;363:2211e2219. 12. Pan WH, Yeh WT, Chen HJ, et al. The U-shaped relationship between BMI and all-cause mortality contrasts with a a p o l l o m e d i c i n e x x x ( 2 0 1 4 ) 1 e4 3 Please cite this article in press as: Mahawar KK, Body mass index: Is it relevant for Indians?, Apollo Medicine (2014), http:// dx.doi.org/10.1016/j.apme.2014.07.013
  • progressive increase in medical expenditure: a prospective cohort study. Asia Pac J Clin Nutr. 2012;21(4):577e587. 13. Flegal KM, Kit BK, Orpana H, Graubard BI. Association of all- cause mortality with overweight and obesity using standard body mass index categories: a systematic review and meta- analysis. J Am Med Assoc. 2013;309(1):71e82. 14. Orpana HM, Berthelot JM, Kaplan MS, Feeny DH, McFarland B, Ross NA. BMI and mortality: results from a national longitudinal study of Canadian adults. Obesity (Silver Spring). 2010;18(1):214e218. 15. McGee DL, Diverse Populations Collaboration. Body mass index and mortality: a meta-analysis based on person-level data from twenty-six observational studies. Ann Epidemiol. 2005;15(2):87e97. 16. Adams KF, Subramanian SV. Commentary: is the concern regarding overweight/obesity in India overstated? Int J Epidemiol. 2008;37(5):1005e1007. 17. Chen Y, Copeland WK, Vedanthan R, et al. Association between body mass index and cardiovascular disease mortality in east Asians and South Asians: pooled analysis of prospective data from the Asia Cohort Consortium. BMJ. 2013;347:f 5446. 18. Pednekar MS, Hakama M, Hebert JR, Gupta PC. Association of body mass index with all-cause and cause-specific mortality: findings from a prospective cohort study in Mumbai (Bombay), India. Int J Epidemiol. 2008;37(3):524e535. 19. Subramanian SV, Perkins JM, Khan KT. Do burdens of underweight and overweight coexist among lower socioeconomic groups in India? Am J Clin Nutr. 2009;90(2):369e376. 20. Subramanian SV, Smith GD. Patterns, distribution, and determinants of under- and overnutrition: a population- based study of women in India. Am J Clin Nutr. 2006;84(3):633e640. 21. Sauvaget C, Ramadas K, Thomas G, Vinoda J, Thara S, Sankaranarayanan R. Body mass index, weight change and mortality risk in a prospective study in India. Int J Epidemiol. 2008;37(5):990e1004. 22. Neuman M, Finlay JE, Davey Smith G, Subramanian SV. The poor stay thinner: stable socioeconomic gradients in BMI among women in lower- and middle-income countries. Am J Clin Nutr. 2011;94(5):1348e1357. 23. Subramanian SV, Perkins JM, €Ozaltin E, Davey Smith G. Weight of nations: a socioeconomic analysis of women in low- to middle-income countries. Am J Clin Nutr. 2011;93(2):413e421. http://dx.doi.org/10.3945/ajcn.110.004820. Epub 2010 Nov 10. 24. Jones-Smith JC, Gordon-Larsen P, Siddiqi A, Popkin BM. Is the burden of overweight shifting to the poor across the globe? Time trends among women in 39 low- and middle-income countries (1991e2008). Int J Obes (Lond). 2012;36(8):1114e1120. 25. Dudeja V, Misra A, Pandey RM, Devina G, Kumar G, Vikram NK. BMI does not accurately predict overweight in Asian Indians in Northern India. Br J Nutr. 2001;86(1):105e112. 26. Rush EC, Freitas I, Plank LD. Body size, body composition and fat distribution: comparative analysis of European, Maori, Pacific Island and Asian Indian adults. Br J Nutr. 2009;102(4):632e641. 27. World Health Organization. WHO Recommendations: Obesity: Preventing and Managing the Global Epidemic. Geneva: World Health Org.; 2000 (Tech. Rep. Ser., no. 894). 28. McKeigue PM, Shah B, Marmot MG. Relation of central obesity and insulin resistance with high diabetes prevalence and cardiovascular risk in South Asians. Lancet. 1991;337(8738):382e386. 29. Segal KR, Dunaif A, Gutin B, Albu J, Nyman A, Pi-Sunyer FX. Body composition, not body weight, is related to cardiovascular disease risk factors and sex hormone levels in men. J Clin Invest. 1987;80(4):1050e1055. 30. Allison DB, Faith MS, Heo M, Kotler DP. Hypothesis concerning the U-shaped relation between body mass index and mortality. Am J Epidemiol. 1997;146(4):339e349. 31. 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(6):953e959. 32. Britton KA, Massaro JM, Murabito JM, Kreger BE, Hoffmann U, Fox CS. Body fat distribution, incident cardiovascular disease, cancer, and all-cause mortality. J Am Coll Cardiol. 2013;62(10):921e925. 33. Varghese B, Swamy S, Srilakshmi MA, et al. Visceral adiposity in young patients with coronary artery disease-a case control study. Indian Heart J. 2012;64(3):284e289. 34. Ninomiya JK, L'Italien G, Criqui MH, Whyte JL, Gamst A, Chen RS. Association of the metabolic syndrome with history of myocardial infarction and stroke in the third national health and nutrition examination survey. Circulation. 2004;109(1):42e46. 35. Lean ME, Han TS, Seidell JC. Impairment of health and quality of life in people with large waist circumference. Lancet. 1998;351(9106):853e856. 36. WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet. 2004;363(9403):157e163. a p o l l o m e d i c i n e x x x ( 2 0 1 4 ) 1 e44 Please cite this article in press as: Mahawar KK, Body mass index: Is it relevant for Indians?, Apollo Medicine (2014), http:// dx.doi.org/10.1016/j.apme.2014.07.013
  • Apollohospitals:http://www.apollohospitals.com/ Twitter:https://twitter.com/HospitalsApollo Youtube:http://www.youtube.com/apollohospitalsindia Facebook:http://www.facebook.com/TheApolloHospitals Slideshare:http://www.slideshare.net/Apollo_Hospitals Linkedin:http://www.linkedin.com/company/apollo-hospitals Blog:Blog:http://www.letstalkhealth.in/