Abstract
Background: Self reporting of health information by participants in employer sponsored programs may result in under reporting of this data. Since policies are formulated on the basis of analysis of available data, underreported data may adversely inform healthcare policy decisions in workplace and other relevant settings. In this study, we examine the disparity in measured versus self reported body mass index (BMI) in a large, diverse working population participating in a work-based Health Risk Assessment (HRA).
Methods: Baptist Health South Florida, a large not-for-profit health care organization, conducts a HRA annually for its employees. The HRA consists of an online health questionnaire and an in-person assessment of biometric measures. Participants report their height and weight in the online questionnaire, and height and weight is measured during collection of biometric information, from which BMI is calculated. BMI was categorized as: not obese (<25kg/m2), obese (30 - 34.9kg/m2) and morbidly obese (≥35kg/m2).
Results: A total of 9536 persons self reported their BMI and subsequently had BMI measured. Mean age of the participants was 43.1 years (± 12.1). Mean BMI was 28.6 (± 6.2) and 27.8 (± 5.9) respectively for measured and self reported BMI respectively. Among all participants, 90% self reported accurately in their respective weight categories, while 9% underreported their weight. However, among obese participants (n=3168), 72% correctly self-reported their BMI. Approximately 29% of obese class I participants reported BMIs in the non-obese category, while about 22% of those with BMI ≥35 kg/m2 reported as being in Obese class I (<35kg/m2). There was a high degree of agreement overall observed between measured and self reported BMI (κ = 0.84; Intra Class Coefficient = 0.89).
Conclusion: Despite of a high degree of overall agreement between measured and self reported BMI, obese participants considerably underreport BMI. Thus, underreporting of self-reported data should be taken into account during program planning and formulation of healthcare policy decisions in the workplace.
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