Journal of Sports Science and Medicine
Journal of Sports Science and Medicine
ISSN: 1303 - 2968   
Ios-APP Journal of Sports Science and Medicine
Androit-APP Journal of Sports Science and Medicine
Views
2673
Download
143
from September 2014
 
©Journal of Sports Science and Medicine (2009) 08, 711 - 712

Letter to editor
Higher Body Mass Index is a Predictor of Death Among Professional Sumo Wrestlers
Hideyuki Kanda , Takehito Hayakawa, Satoshi Tsuboi, Yayoi Mori, Teruna Takahashi, Tetsuhito Fukushima
Author Information
Department of Hygiene and Preventive Medicine, Fukushima Medical University, Fukushima, Japan

Hideyuki Kanda
✉ Department of Hygiene and Preventive Medicine, Fukushima Medical University, Fukushima, Japan.
Email: hkanda@fmu.ac.jp
Publish Date
Received: 30-10-2009
Accepted: 16-11-2009
Published (online): 01-12-2009
Share this article
 
Dear Editor-in-chief

Sumo wrestling, Japan’s national sport, have a long history over 300 years in Japan. Sumo is becoming well-known all over the world as one of Japanese culture (Nagayama, 2008). As you know, professional Sumo wrestlers are expected to lead specific lifestyles that promote increases in body weight after go professional. This notion makes Sumo wrestlers a unique group of professional athletes unlike any other sport in that they are all obese. In a previous studie on the life expectancies of professional Sumo wrestlers, the result suggested higher body weight led to shorter life expectancies compared to general population (Hoshi and Inaba, 1995). The aim of present study is to clarify that higher body mass index is a predictor of death among professional Sumo wrestlers or not.

Data for all Sumo wrestlers who were promoted to the top division, generally called Nyuumaku, between the years of 1926 and 1989 were compiled using The Professional Sumo Wrestler Directory (Mizuno and Kyosu, 2006). Of the 430 wrestlers listed on the Directory as having made their Nyuumaku between the years from 1926 to 1989, 73 were deceased. Therefore, this study was a case-control study consisting of 73 deceased wrestlers born between the years 1908 to 1955 as cases, and 73 surviving wrestlers with matching birth years as controls. To compare means and frequencies of the variables between cases and controls, t-tests were used for continuous variables, while chi-square tests were used for categorical variables. A multiple logistic regression analysis was used to assess the contribution of each independent variable to death. To further describe predictive properties of a death factor, areas under receiver operating characteristic (ROC) curve for death among Sumo wrestlers were calculated. ROC curves were calculated across all possible death factors. The Statistical Package for the Social Sciences (SPSS Japan Inc. version 13.0J, Tokyo, Japan) was used to conduct the analyses.

After analysed by t-tests or chi-square tests, deceased wrestlers had higher body mass indexes with statistical significance as well as higher winning percentages, won more performance prizes (performance prizes in sumo are given out for outstanding performance, fighting-spirit, or technique) in their careers, and more were ranked higher. Table 1 shows the odds ratios and 95% confidential intervals of each independent factor related to death among Sumo wrestlers using a multiple logistic regression analysis. BMI was a statistically significant death determinant among Sumo wrestlers. As shown in Figure 1, an analysis of the ROC curve for BMI in the prediction of death events suggested reasonable accuracy in the area under the curve of 0.685 (95% confidence interval, 0.597-0.772). A tradeoff between sensitivity and specificity did not suggest an optimal BMI for a cutoff for prediction of death (Akobeng, 2007).

The present study suggests a higher BMI has strong affects on death and has statistical significance among Sumo wrestlers by case-control study, though we could not find an optimal BMI cutoff point for the prediction of death. It is noteworthy that this study was able to identify that a certain weight of a Sumo wrestler at a point in his career can show affects on his death, in spite of weight being a fluctuating variable.

There are some limitations in the present study. First, we could not assess the details of body composition, cause of death and the effects of other common risk factors of death such as smoking and alcohol consumption, largely because the data used was secondary data from The Professional Sumo Wrestler Directory. Second, this was a case-control study, so our results may include some bias. Finally, there were only 73 deceased Sumo wrestlers examined in this study, implying a need to carry on further research regarding this topic in the future.

This study suggests that an higher BMI can be a predictive factor of death even amongst Sumo wrestlers, and that proper guidelines for taking care of their health are necessary.

AUTHOR BIOGRAPHY

Journal of Sports Science and Medicine Hideyuki Kanda
Employment: Department of Hygiene and Preventive Medicine, Fukushima Medical University
Degree:
Research interests:
E-mail: hkanda@fmu.ac.jp
 

Journal of Sports Science and Medicine Takehito Hayakawa
Employment: Department of Hygiene and Preventive Medicine, Fukushima Medical University
Degree:
Research interests:
E-mail:
 

Journal of Sports Science and Medicine Satoshi Tsuboi
Employment: Department of Hygiene and Preventive Medicine, Fukushima Medical University
Degree:
Research interests:
E-mail:
 

Journal of Sports Science and Medicine Yayoi Mori
Employment: Department of Hygiene and Preventive Medicine, Fukushima Medical University
Degree:
Research interests:
E-mail:
 

Journal of Sports Science and Medicine Teruna Takahashi
Employment: Department of Hygiene and Preventive Medicine, Fukushima Medical University
Degree:
Research interests:
E-mail:
 

Journal of Sports Science and Medicine Tetsuhito Fukushima
Employment: Department of Hygiene and Preventive Medicine, Fukushima Medical University
Degree:
Research interests:
E-mail:
 
REFERENCES
Journal of Sports Science and Medicine Akobeng A.K. (2007) Understanding diagnostic tests 3: Receiver operating characteristic curves. Acta Paediatrics 96, 644-6477.
Journal of Sports Science and Medicine Hoshi A., Inaba Y. (1995) Risk factors for mortality and mortality rate of sumo wrestlers. Nippon Eiseigaku Zasshi 50, 730-736.
Journal of Sports Science and Medicine Mizuno N., Kyosu T (2006) The professional sumo wrestler directory. Tokyo. Kyodo News Company, Inc..
Journal of Sports Science and Medicine Nagayama S (2008) Ohzumo. Sumo, borderless.
Journal of Sports Science and Medicine Niki Y. (1969) Journal of the Japanese Diabetes Society.
Journal of Sports Science and Medicine Akobeng A.K. (2007) Understanding diagnostic tests 3: Receiver operating characteristic curves. Acta Paediatrics 96, 644-6477.
Journal of Sports Science and Medicine Hoshi A., Inaba Y. (1995) Risk factors for mortality and mortality rate of sumo wrestlers. Nippon Eiseigaku Zasshi 50, 730-736.
Journal of Sports Science and Medicine Mizuno N., Kyosu T (2006) The professional sumo wrestler directory. Tokyo. Kyodo News Company, Inc..
Journal of Sports Science and Medicine Nagayama S (2008) Ohzumo. Sumo, borderless.
Journal of Sports Science and Medicine Niki Y. (1969) Journal of the Japanese Diabetes Society.
 
 
 
Home Issues About Authors
Contact Current Editorial board Authors instructions
Email alerts In Press Mission For Reviewers
Archive Scope
Supplements Statistics
Most Read Articles
  Most Cited Articles
 
  
 
JSSM | Copyright 2001-2020 | All rights reserved. | LEGAL NOTICES | Publisher

It is forbidden the total or partial reproduction of this web site and the published materials, the treatment of its database, any kind of transition and for any means, either electronic, mechanic or other methods, without the previous written permission of the JSSM.

This work is licensed under a Creative Commons License Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.