• Open Access

Correlations between physiology and lifespan – two widely ignored problems with comparative studies

Authors

  • John R. Speakman

    Corresponding author
    1. Aberdeen Centre for Energy Regulation and Obesity (ACERO), School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland, UK, and ACERO, Division of Energy Balance and Obesity, Rowett Research Institute, Bucksburn Road, Aberdeen, Scotland, UK
      Dr John R. Speakman, Aberdeen Centre for Energy Regulation and Obesity (ACERO), School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland, UK. Tel.: +44 (0)1224 272879, Fax: +44 (0)1224 272396; e-mail: j.speakman@abdn.ac.uk.
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Dr John R. Speakman, Aberdeen Centre for Energy Regulation and Obesity (ACERO), School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland, UK. Tel.: +44 (0)1224 272879, Fax: +44 (0)1224 272396; e-mail: j.speakman@abdn.ac.uk.

Summary

Comparative differences between species provide a powerful source of information that may inform our understanding of the aging process. However, two problems regularly attend such analyses. The co-variation of traits with body mass is frequently ignored, along with the lack of independence of the data due to a shared phylogenetic history. These problems undermine the use of simple correlations between various factors and maximum lifespan potential (MLSP) across different species as evidence that the factors in question have causal effects on aging. Both of these problems have been widely addressed by comparative biologists working in fields other than aging research, and statistical solutions to these issues are available. Using these statistical approaches, of making analyses of residual traits with the effects of body mass removed, and deriving phylogenetically independent contrasts, will allow analyses of the relationships between physiology and maximum lifespan potential to proceed unhindered by these difficulties, potentially leading to many useful insights into the aging process.

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