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• The limitations of body mass index - response
  Yize I Wan, John R Prowle
  Published on: 4 February 2021
• Comparing outcomes between ethnic groups - the limitations of body mass index.
  Pradipta Bhakta, Brian O'Brien
  Published on: 1 February 2021

• Published on: 4 February 2021

  The limitations of body mass index - response

  • Yize I Wan, Clinical Lecturer in Anaesthesia and Intensive Care Medicine Queen Mary University of London
  • Other Contributors:
    • John R Prowle, Senior Clinical Lecturer in Intensive Care Medicine

  Dear Dr Bhakta and Dr O'Brien,
  We are grateful for the very valid insights. Our intention was not to explore BMI as a COVID risk factor due to reasons such as incomplete data and measurement accuracy, but to account for it as a potentially confounding variable in the relationship between ethnicity and outcome. Evidence regarding ethnic differences in BMI remains sparse and historic reports may not accurately reflect cohorts represented in contemporary publications. This is nevertheless an important subject to address for future research.
  Yize I Wan,
  John R Prowle

  Conflict of Interest:
  None declared.

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• Published on: 1 February 2021

  Comparing outcomes between ethnic groups - the limitations of body mass index.

  • Pradipta Bhakta, Anaesthesiologist and Intensivist Consultant, Department of Anaesthesiology and Intensive Care, University Hospital Kerry, Tralee, Co: Kerry, Ireland.
  • Other Contributors:
    • Brian O'Brien, Anesthesiologist and Intensivist

  Dear Editor,
  Apea VJ et al. should be congratulated on elucidating the interplay between overlapping factors that influence patient outcomes from COVID-19. From the first reports about this disease, observers have noted that adipose tissue, perhaps through its association with diabetes and heart disease, has been linked to the severity of presentation and to subsequent clinical course. In studying a cosmopolitan patient population in a single large centre, the authors have cleverly eliminated many confounding factors and allowed the influence of ethnicity, per se, to be assessed.
  In this context though, the use of body mass index as a measure of obesity may be too blunt a discriminator. While a BMI of 30 kg/m2 is conventionally taken to define obesity, this measure has significant limitations.2,3 The most obvious is that it does not actually measure lean versus fatty tissue.3 More particularly, the BMI or Quetelet index threshold of 30 kg/m2 may be insensitive to the presence of obesity in those of Asian origin.4 Other authors have shown that the cut off in Asians may be optimally set at a lower level (e.g. 27 kg/m2 for men, and as low as 25 kg/m2 for women).5 We wonder, were Apea VJ et al.’s observations re-examined using such thresholds, if the poor outcomes seem in Asian patients would be more fully accounted for?
  We would welcome their views on this question. As the world’s most populous countries are in Asia, and the...

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  Dear Editor,
  Apea VJ et al. should be congratulated on elucidating the interplay between overlapping factors that influence patient outcomes from COVID-19. From the first reports about this disease, observers have noted that adipose tissue, perhaps through its association with diabetes and heart disease, has been linked to the severity of presentation and to subsequent clinical course. In studying a cosmopolitan patient population in a single large centre, the authors have cleverly eliminated many confounding factors and allowed the influence of ethnicity, per se, to be assessed.
  In this context though, the use of body mass index as a measure of obesity may be too blunt a discriminator. While a BMI of 30 kg/m2 is conventionally taken to define obesity, this measure has significant limitations.2,3 The most obvious is that it does not actually measure lean versus fatty tissue.3 More particularly, the BMI or Quetelet index threshold of 30 kg/m2 may be insensitive to the presence of obesity in those of Asian origin.4 Other authors have shown that the cut off in Asians may be optimally set at a lower level (e.g. 27 kg/m2 for men, and as low as 25 kg/m2 for women).5 We wonder, were Apea VJ et al.’s observations re-examined using such thresholds, if the poor outcomes seem in Asian patients would be more fully accounted for?
  We would welcome their views on this question. As the world’s most populous countries are in Asia, and the pandemic continues apace, this is perhaps a matter of the very greatest global health importance.
  Pradipta Bhakta,
  Brian O’Brien.
  References:
  1. Apea VJ, Wan YI, Dhairyawan R, et al. Ethnicity and outcomes in patients hospitalised with COVID-19 infection in East London: an observational cohort study. BMJ Open. 2021 Jan 17;11(1):e042140. doi: 10.1136/bmjopen-2020-042140. PMID: 33455936; PMCID: PMC7813387.
  2. Obesity: preventing and managing the global epidemic. Report of a WHO consultation. World Health Organ Tech Rep Ser. 2000;894:i-xii, 1-253.
  3. Frankenfield DC, Rowe WA, Cooney RN, Smith JS, Becker D. Limits of body mass index to detect obesity and predict body composition. Nutrition. 2001;17(1):26-30.
  4. WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet. 2004;363(9403):157-63.
  5. Goh VH, Tain CF, Tong TY, Mok HP, Wong MT. Are BMI and other anthropometric measures appropriate as indices for obesity? A study in an Asian population. J Lipid Res. 2004;45(10):1892-8.

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  Conflict of Interest:
  None declared.

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