Accuracy of self-reported weight, height and BMI in US firefighters.
BACKGROUND
Obesity is of increasing concern especially among firefighters. Bias in self-reported body weight, height and body mass index (BMI) has received a great deal of attention given its importance in epidemiological field research on obesity.


OBJECTIVE
To determine the validity of self-reported weight, height and BMI and identify potential sources of bias in a national sample of US firefighters.


METHODS
Self-reported and measured weight and height (and BMI derived from them) were assessed in a national sample of 1001 career male firefighters in the USA and errors in self-reported data were determined.


RESULTS
There were 1001 participants. Self-reported weight, height and BMI were significantly correlated with their respective measured counterparts, i.e. measured weight (r = 0.990; P < 0.001), height (r = 0.961; P < 0.001) and BMI (r = 0.976; P < 0.001). The overall mean difference and standard deviation between self-reported weight, height and BMI were 1.3±2.0kg, 0.94±1.9cm and 0.09±0.9kg/m(2), respectively, for male firefighters. BMI-based weight status (P < 0.001) was the most consistent factor associated with bias in self-reported BMI, weight and height, with heavier firefighters more likely to underestimate their weight and overestimate their height, resulting in underestimated BMIs. Therefore, using self-reported BMI would have resulted in overestimating the prevalence of obesity (BMI ≥ 30.0) by 1.8%, but underestimating the prevalence of more serious levels of obesity (Class II and III) by 1.2%.


CONCLUSIONS
Self-reported weight and height (and the resulting BMI) were highly correlated with measured values. A primary and consistent source of error in self-reported weight, height and BMI based on those indices was BMI-based weight status.
Center for Fire, Rescue and EMS Health Research, Institute for Biobehavioral Health Research, NDRI-MA, NDRI: National Development and Research Institutes, Inc., Leawood, KS 66224, USA, poston@ndri.org.
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Poston
Center for Fire, Rescue and EMS Health Research, Institute for Biobehavioral Health Research, NDRI-MA, NDRI: National Development and Research Institutes, Inc., Leawood, KS 66224, USA.
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Jitnarin
Center for Fire, Rescue and EMS Health Research, Institute for Biobehavioral Health Research, NDRI-MA, NDRI: National Development and Research Institutes, Inc., Leawood, KS 66224, USA.
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Haddock
Center for Fire, Rescue and EMS Health Research, Institute for Biobehavioral Health Research, NDRI-MA, NDRI: National Development and Research Institutes, Inc., Leawood, KS 66224, USA.
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Jahnke
Division of Epidemiology, Human Genetics, and Environmental Sciences, Michael & Susan Dell Center for Healthy Living, University of Texas Houston Health Sciences Center, Houston, TX 77030, USA.
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D000328:Adult; D015982:Bias; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D061388:Firefighters; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D015995:Prevalence; D015203:Reproducibility of Results; D057566:Self Report; D012737:Sex Factors; D012858:Size Perception; D011795:Surveys and Questionnaires; D014481:United States; D055815:Young Adult
Anthropometry; firefighter; fitness; obesity.