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  • Letter to the Editor
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Reply to Flegal et al.

International Journal of Obesity volume 32, pages 876–877 (2008)Cite this article

We are pleased by Flegal et al.'s interest in our work1 and grateful for the opportunity to dialogue and clarify any issues on which there may be misunderstandings. After Flegal et al. published their 2005 findings,2 Flegal3 wrote that it is ‘important to clarify in our article that any associations of weight with mortality were not necessarily causal but might be due, wholly or in part, to other factors… that were associated both with weight and with mortality.’ We agree and are attempting to explore one class of putative confounding factors, namely those related to illness, aging and measurement error that might lead to underestimates of the effects of obesity on mortality rate.

The key point of Flegal et al.'s letter is unclear to us, and perhaps it was unclear as to the key point of our paper.1 The main points of our paper are (A) there are different analytic methods that different experts have used to estimate the hazard ratios (HRs) for obesity with no universal consensus as to the most appropriate method; (B) some of these different methods that are intended to reduce confounding yielded radically different (higher) HRs in the ARIC data we analyzed as well as in some other data sets; (C) this finding supports the conjecture that the true causal effects of obesity on mortality rate, expressed as HRs, might be different, perhaps substantially larger than those presented in Flegal et al.2 and finally; (D) all other things being equal, marked increases in estimated HRs will lead to marked increases in estimates of deaths attributable to obesity. There appears to be nothing in Flegal et al.'s letter, which suggests that the main thrust of our paper is incorrect. Flegal et al. also do not seem to disagree with the idea that different HRs yield different estimates of mortality attributable to obesity. In fact they made the same point on several occasions (see below).

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References

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Authors and Affiliations

  1. Department of Health and Nutrition Sciences, Brooklyn College of the City University of New York, Brooklyn, NY, USA

    J Greenberg

  2. Division of Rheumatology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA

    K Fontaine

  3. Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL, USA. E-mails: jamesg@brooklyn.cuny.edu, kfontail@jhmi.edu and dallison@uab.edu,

    D B Allison

Authors
  1. J Greenberg
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  2. K Fontaine
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  3. D B Allison
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Greenberg, J., Fontaine, K. & Allison, D. Reply to Flegal et al.. Int J Obes 32, 876–877 (2008). https://doi.org/10.1038/sj.ijo.0803804

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