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Statistics LibreTexts

20.20: Weight and Sleep Apnea

  • Page ID
    2542
  • Skills to Develop

    • Excess Body Weight and Sleep Apnea  

    Research conducted by

    Kari Johansson, Erik Hemmingsson, Richard Harlid, Ylva Trolle Lagerros, Fredrik Granath, Stephan Rössner, and Martin Neovius 

    Statistical article authored by

    Philip Sedgwick

    Case study prepared by

    Robert F. Houser and Georgette Baghdady

    Overview

    In his statistical article, “Standard deviation versus standard error,” UK researcher Philip Sedgwick presents us with an interesting discussion of the proper use of standard deviation (SD) and standard error of the mean (SEM).  He uses an example of a weight loss study of \(63\) obese men suffering from obstructive sleep apnea who were being treated with continuous positive airway pressure (CPAP).  The weight loss program lasted one year.  Outcome measures included change in body weight measured in kilograms (kg).

    More than \(60\%\) of people experiencing obstructive sleep apnea are obese.  CPAP therapy is the most common treatment.  It uses a machine and mask to prevent the airway from collapsing, thus enabling a person to breathe more easily during sleep.  Weight loss is an effective treatment for sleep apnea. 

    Questions to Answer

    What is the proper use of the SD?  What is the proper use of the SEM?

    Design Issues 

    None for the Sedgwick article. 

    Descriptions of Variables

    Table \(\PageIndex{1}\): Description of Variables

    Variable Description
    Weight Body weight at baseline in kg
    Weight change Change in body weight at one year from baseline in kg

    References

    • Sedgwick, P. (2011). Standard deviation versus standard error. BMJ, 343, d8010.
    • Johansson, K., Hemmingsson, E., Harlid, R., Lagerros, Y. T., Granath, F., Rössner, S., Neovius, M. (2011). Longer term effects of very low energy diet on obstructive sleep apnoea in cohort derived from randomised controlled trial: prospective observational follow-up study. BMJ, 342, d3017.

    Contributor

    • Online Statistics Education: A Multimedia Course of Study (http://onlinestatbook.com/). Project Leader: David M. Lane, Rice University.