Skip to main content

Statistical comments on “no seasonal variation in physical activity of Han Chinese living in Beijing”

Dear Editor,

We read with great interest the recent article by Wang et al. [1] entitled, “No seasonal variation in physical activity of Han Chinese living in Beijing”. In this study, the authors evaluated physical activity levels every two months across a complete year, while simultaneously assessed ambient temperatures and air pollution levels. They also investigated average hourly vector magnitude and percentage time spent at each physical activity. In this regard, 40 Han Chinese adults using GT3X accelerometers were recruited. Although this study was mostly a well-designed research, we have the following comments from a statistical point of view. In the statistical analysis section of the article, the authors stated that they used one way ANOVA to compare whether there were changes in body weight and body fitness between months. One way ANOVA is used for comparison of the means of more than two independent groups [2,3,4]. But the groups of this study are not independent, because they did not use different groups at each time points of evaluation (every two months). Indeed, they measured their variables in one group of 40 adults every two months across a complete year. Therefore, there were not independent groups in this study and they investigated one group at different time points. After assessment of the normal distribution of studied quantitative variables, the authors must use Repeated Measures ANOVA or Friedman test for comparison of the means of each variable at different times of measurement.

Taken together, we believe that most used statistical tests in this study and also results and discussion based on them are inappropriate and the author’s valuable study could better be used as citable clinical evidence if analyzed with appropriate statistical tests.

References

  1. 1.

    Wang G, et al. No seasonal variation in physical activity of Han Chinese living in Beijing. Int J Behav Nutr Phys Act. 2017;14(1):48.

    Article  PubMed  PubMed Central  Google Scholar 

  2. 2.

    Gaddis ML. Statistical methodology: IV. Analysis of variance, analysis of co variance, and multivariate analysis of variance. Acad Emerg Med. 1998;5(3):258–65.

    CAS  Article  PubMed  Google Scholar 

  3. 3.

    Farrokhi M, Masoudifar A, Peykanpour F. Interleukin 17 and 10 in relapsing remitting multiple sclerosis. J Neurol Sci. 2017;378:63.

    CAS  Article  PubMed  Google Scholar 

  4. 4.

    Farrokhi M. Sema3A and multiple sclerosis. Gene. 2017;615:41.

    CAS  Article  PubMed  Google Scholar 

Download references

Author information

Affiliations

Authors

Contributions

MF participated in the design of the study and mansucrtipt development. NS participated in the design of the study and manuscript development. Both authors read and approved the final manuscript.

Corresponding author

Correspondence to Mehrdad Farrokhi.

Ethics declarations

Competing interests

The authors declare that there is no conflict of interest regarding the publication of this article.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Farrokhi, M., Shirian, N. Statistical comments on “no seasonal variation in physical activity of Han Chinese living in Beijing”. Int J Behav Nutr Phys Act 14, 151 (2017). https://doi.org/10.1186/s12966-017-0604-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/s12966-017-0604-x