Can self-reported BMI be used as a valid measure among novice runners

Martin Serup Juul, R.O. Nielsen, Sten Rasmussen

Research output: Contribution to conferencePosterResearchpeer-review

Abstract

There is an increased risk of running related injuries (RRI) among novice runners with
a Body Mass Index (BMI) above 25. Information about BMI can be collected through
questionnaires, when studies investigate if there is an association between BMI and
RRI among novice runners. But can self-reported BMI be used as a valid measure
compared to BMI measured with a calibrated weight.
PURPOSE : To determine the validity of self-reported BMI among novice runners.
METHODS: Data on BMI was obtained from a prospective follow-up study
investigating the link between training exposure and the development of RRI. Healthy
novice runners between the age of 18 to 65 and without lower extremity injuries
were able to participate in the study. During July and August 2011 the participants
were included in the study based on an online questionnaire. 1532 persons completed
the questionnaire, of these, 970 were invited to a test at baseline after meeting the
requirements for participation. Information about BMI was obtained in two ways;
firstly, from the online based questionnaire where the participants had to report height
and weight themselves. Secondly, the weight was measured with calibrated weight
(Tanita SC-330) while their height was measured with a tape measure. Based on these
data BMI were calculated based on the equation: BMI = mass (kg) / (height (m))2.
Paired t-test was used to compare mean difference between self-reported BMI and
measured BMI. Bland Altman limits of agreement were used to calculate the 95 %
prediction limits.
RESULTS : A total of 931 participants were measured and eligible to participate, of
these, 2 were excluded due to data loss. The gender distribution was; 464 women with
a mean age of 36.8 ±10.0 and a measured BMI of 25.4 ± 4.2 and 465 men with a mean
age of 37.6 ± 10.6 and a measured BMI of 26.6 ± 3.8. Compared with measured BMI
both men and women had a significant lower mean self-reported BMI of -0.23 [-0.34;
-0.12], p<0.001 and -0.41 [-0.51; -0.31], p<0.001, respectively. Among men and
women the 95% limits of agreement were from -2.63 to 2.72 and from -2.56 to 1.74,
respectively.
CONCLUSION : Based on the findings from current study, BMI based on selfreported
height and weight should be used with caution if the association between BMI
and RRI is investigated.
Original languageEnglish
Publication date2 Jun 2012
Number of pages1
Publication statusPublished - 2 Jun 2012
Event3rd World Congress on Exercise is Medicine: American College of Sports Medicine - San Fransisco, United States
Duration: 29 May 20122 Jun 2012
Conference number: 3

Conference

Conference3rd World Congress on Exercise is Medicine
Number3
Country/TerritoryUnited States
CitySan Fransisco
Period29/05/201202/06/2012

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