Does BMI generated by self-reported height and weight measure up in older adults from middle-income countries? Results from the study on global AGEing and adult health (SAGE).

Theresa E Gildner,Tyler M Barrett,Melissa A Liebert,Paul Kowal,J Josh Snodgrass

doi:10.1186/s40608-015-0074-0

Theresa E Gildner, Tyler M Barrett + Show 3 more

Open Access

https://doi.org/10.1186/s40608-015-0074-0

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Abstract

BackgroundSelf-reported (SR) body mass index (BMI) values are often used to determine obesity prevalence. However, individuals frequently overestimate their height and underestimate their weight, resulting in artificially lower obesity prevalence rates. These patterns are especially apparent among older adults and overweight individuals. The present cross-sectional study uses nationally representative datasets from five countries to assess the accuracy of SR BMI values in diverse settings.MethodsSamples of older adults (≥50 years old) and comparative samples of younger adults (18–49 years old) were drawn from five middle-income countries (China, India, Mexico, Russian Federation, and South Africa) in the World Health Organization’s Study on global AGEing and adult health (SAGE). Participant-reported and researcher-obtained height and weight measures were used to calculate SR and measured BMI, respectively. Paired t-tests assessed differences between SR and measured BMI values by country. Linear regressions examined the contribution of measured weight and age to differences between SR and measured BMI.ResultsSignificant differences between SR and measured BMI values were observed (p < 0.05), but the direction of these discrepancies varied by country, age, and sex. Measured weight significantly contributed to differences between SR and measured BMI in all countries (p < 0.01). Age did not contribute significantly to variation in BMI discrepancy, except in China (p < 0.001).ConclusionsThese results suggest that SR BMI may not accurately reflect measured BMI in middle-income countries, but the direction of this discrepancy varies by country. This has considerable implications for obesity-related disease estimates reliant on SR data.

Highlights

Self-reported (SR) body mass index (BMI) values are often used to determine obesity prevalence
Differences between reported and measured BMI by age group The results of the paired t-tests indicated that significant differences exist between SR and measured BMI values
Mean SR BMI was significantly higher than mean measured BMI in India and South Africa, while mean SR BMI was lower than mean measured BMI in Russia (Table 1)

Summary

Introduction

Self-reported (SR) body mass index (BMI) values are often used to determine obesity prevalence. Individuals frequently overestimate their height and underestimate their weight, resulting in artificially lower obesity prevalence rates. These patterns are especially apparent among older adults and overweight individuals. The use of SR height and weight values has several advantages, including low Gildner et al BMC Obesity (2015) 2:44 global increases in obesity This information is required to design intervention programs that effectively reduce associated disease burden. Villanueva (2001) found that 25 % of US men and 35 % of US women underreport their weight [11] This misreporting results in lower obesity prevalence rates when SR data are used to calculate BMI, and these inaccurate values have considerable policy and public health implications. It is unlikely that SR BMI identifies all overweight and obese individuals, impeding the implementation of targeted interventions and the interpretation of lifestyle factors that increase obesity risk [12]

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