Corrective Equations to Self-Reported Height and Weight for Obesity Estimates Among U.S. Adults: NHANES 1999-2008

Abstract

Purpose: Estimating obesity prevalence using self-reported height and weight is an economic and effective method and is often used in national surveys. However, self-reporting of height and weight can involve misreporting of those variables and has been found to be associated to the size of the individual. This study investigated the biases in self-reporting of height and weight in the U.S. adult population and generated age-adjusted correction equations for self-reported height and weight separately for each ethnic group's specific height and weight quartile sample. Validity of the body mass index (BMI) classification calculated from corrected self-reported height and weight was also examined.

Method: Data on self-reporting and direct measurement of height and weight from National Health and Nutrition Examination Survey 1999-2008 were analyzed. The final sample included 11,521 men and 10,905 nonpregnant women who were all U.S. citizens aged 20 years or older.

Results: A variation in misreporting of self-reported height and weight depended on the gender, ethnicity, age, and size of the individual. The results from sensitivity and specificity analyses showed that the BMI calculated from corrected values of self-reported height and weight provided more accurate estimations of overweight and obesity than did BMI calculated from self-reported height and weight.

Conclusion: In spite of some methodological concerns, the correction equation of self-reported height and weight generated in this study can be utilized as a method for quick assessment of estimating the obesity and overweight prevalence in the U.S. adult population.

Keywords: Body mass index; complex sample analysis; sensitivity; specificity.