Accuracy of Self-reported Weight and Height in Binge Eating Disorder: Misreport Is Not Related to Psychological Factors
This study examined the degree of misreport in weight, height, and BMI among overweight adults (n = 392) with binge eating disorder (BED) and tested whether the degree of misreport was associated with eating disorder psychopathology and psychological variables. Male (n = 97) and female (n = 295) participants self-reported height and weight, and were subsequently measured by clinic staff. Participants also completed a series of diagnostic interviews and self-report assessments. Discrepancies between self-reported and measured values were modest. The degree of misreport for weight, height, and BMI was not related to eating disorder features, depression, and self-esteem. Overall, the errors in self-reported weight and height by overweight patients with BED were very slight. The degree of discrepancy between self-reported and measured values was not related to eating disorder or psychological features, suggesting that such data are not biased or systematically related to individual differences in overweight patients with BED.
Self-reported weight and height are frequently used in epidemiological studies as proxies for measured anthropometric data. Previous research on the accuracy of self-reported weight and height has found high correlations (i.e., r's >0.9) between self-report and actual measurements, indicating the suitability of using these data (1,2). When errors in self-report occur, they tend to be in the direction of underreporting weight and overreporting height (3), and there is evidence of various forms of systematic biases. For example, women are more likely to underreport weight than men, as are individuals who are attempting to lose weight (4), and the degree of underreporting is significantly related to BMI, such that greater reporting error is associated with greater BMI (4,5). Research has found that individuals with eating disorders (i.e., bulimia nervosa) are more accurate in their weight self-reports than normal controls, and this has been speculated to be due to the heightened weight-related preoccupation intrinsic to eating disorders (6).
The pattern and clinical relevance of weight misreport among overweight individuals with binge eating disorder (BED) remains poorly understood. In keeping with previous research (e.g., (4,5)), it could be that overweight individuals with BED may experience greater reporting error as would be predicted by higher BMI. Alternatively, in line with research showing reduced reporting error associated with eating disorders (6), individuals with BED could be accurate reporters as a function of elevated weight preoccupation. Within this clinical group, the relevance of weight misreport on eating psychopathology remains unclear. Masheb and Grilo (7), with a sample of 108 obese patients (mean BMI = 36.3) with BED, found that most patients were accurate in self-reporting weight, and that accurate reporters and inaccurate reporters (defined as ±5 pounds) did not differ significantly in eating psychopathology. In contrast, Meyer et al. (8), in a study of 105 female university-student volunteers (mean BMI = 21.9), found that participants underestimated their weights and overestimated their heights, and that the degree of misreported weight was significantly associated with eating psychopathology as measured with the self-report eating disorder examination (EDE) Questionnaire (9). Specifically, in this group of normal-weight women, eating concerns were positively associated with weight overestimation, whereas elevated weight concerns were associated with weight underestimation. Meyer et al. (8) concluded that research on patients with eating disorders that relies on self-reported weight and height data is skewed. There are several possible explanations for these contrasting conclusions, including different BMI ranges of the samples, nonclinical vs. clinical samples, and the analytical approach of the two papers.
The current article seeks to employ a continuous data analytic approach, similar to that employed by Meyer et al. (8), to investigate the accuracy of self-reported weight and height data, and to examine whether the degree of misreport is associated with eating disorder psychopathology and associated psychological functioning in a large series of overweight patients with BED. The discrepancy between self-reported and actual measures was also investigated across men and women and across racial/ethnic groups to examine whether systematic differences occurred across demographic groups.
Methods and Procedures
Participants were 392 adults recruited for treatment studies, who met full DSM-IV research criteria for BED. Average age of the participants was 45.1 years (s.d. = 9.0); average BMI was 37.3 (s.d. = 6.6; range 25–59). The sample was 24.7% male (n = 97) and 75.3% female (n = 295). The racial/ethnic distribution was 81.9% white (n = 321), 10.2% African American (n = 40), 5.4% Hispanic (n = 21), 1% Asian (n = 4), and 1.6% “other” or missing (n = 6). In terms of educational attainment, 0.8% (n = 3) reported less than a high school degree, 15.6% (n = 61) graduated from high school, 35.6% (n = 143) completed some college, 46.4% (n = 182) had a college degree, and 0.8% (n = 3) did not report.
Participants completed a battery of self-report questionnaires, which included items for self-reported weight and height, and were then interviewed by experienced doctoral-level research-clinicians who were trained in the administration of all interviews and measures. Actual measurements of weight and height were obtained after the self-report was complete, and during the initial assessment meeting using a calibrated medical balance beam scale. The self-reported and measured weight and height values were used to calculate self-reported BMI and actual BMI.
BED diagnosis was determined by doctoral-level research-clinicians using the Structured Clinical Interview for DSM-IV Disorders (10) and the EDE (11). The EDE, a semistructured interview, focuses on the previous 28 days except for diagnostic items, which are rated for the durations stipulated in the DSM-IV. The EDE is a well-established interview (12) with good inter-rater and test–retest reliability in BED (13). The EDE assesses the frequency of different forms of overeating, including objective bulimic episodes (binge eating defined as unusually large amounts of food with a subjective sense of loss of control), and comprises four scales (dietary restraint, eating concern, weight concern, and shape concern).
In addition, participants completed the following self-report questionnaires:
Beck Depression Inventory. Beck Depression Inventory-21 (14) assesses current depression level and symptoms of depression. It is a widely used and well-established measure with excellent reliability and validity (15). Higher scores reflect higher levels of depression.
Rosenberg self-esteem scale. The Rosenberg self-esteem scale (16) is a 10-item well-established and widely used measure of global self-esteem. Subjects rate the items on a scale from 1 (strongly agree) to 4 (strongly disagree); higher scores reflect higher self-esteem.
Table 1 provides the mean self-reported and measured weight, height, and BMI, as well as tests of association between self-reported and actual measures. Mean values indicate a significant underestimation of weight (mean difference score of 1 kg underestimation) and a nonsignificant overestimation of height (by a mean of 0.1 cm). These misestimations resulted in an overall significant underestimation of BMI of <1 BMI unit. The significant correlations between self-reported and measured values were very high.
Table 1. Associations between self-reported and measured anthropometric indexes
Table 2 provides discrepancy scores (self-reported value minus measured value) separately by gender. Men and women did not differ significantly in their tendency to underreport weight, height, or BMI. Racial/ethnic groups (African American, Hispanic, and white) were also compared on degree of misreport. Analyses of variance found no significant differences across the race/ethnicity groups for misreporting in weight (F(2, 379) = 1.54, P = 0.22), height (F(2, 379) = 1.36, P = 0.26), or BMI (F(2, 379) = 1.51, P = 0.22).
Table 2. Comparison of discrepancy scores across gender groups
Table 3 reports the results of correlation analyses examining the relationships between reporting discrepancies and age, actual BMI, eating disorder psychopathology, and psychological functioning. BMI discrepancy scores were associated with measured BMI; underreporting of BMI was associated with increasing BMI. Reporting discrepancies were not significantly associated with any of the eating disorder features, including binge eating and EDE subscales. Reporting error was also unrelated to depression and self-esteem.
Table 3. Correlations of discrepancy variables with clinical variables
The current study investigated the accuracy of self-reported weight and height in a large series of overweight men and women with BED and examined whether the degree of misestimation was associated with demographic factors, features of eating disorders, and associated psychological factors. Consistent with previous reports (e.g., refs. 1,2), correlations between self-reported and measured values for weight, height, and BMI exceeded 0.9. The degree of weight and height misreport was generally modest. The mean degree of misestimation in weight was ∼1 kg, and mean misestimation in height was <1 cm. Together, this amounted to a mean underestimation in BMI of approximately one-half of a BMI unit.
In this study group of overweight patients with BED, men and women did not differ significantly in their accuracy of self-reported weight, height, or BMI. Racial/ethnic group comparisons revealed no significant differences in the degree of misreport between white, black, and Hispanic groups. This nonsignificant finding contrasts with some previous findings of significant racial differences in misestimation among extremely obese bariatric surgery patients (17). It is possible that the relatively limited sample sizes of minorities in the present study did not allow us to detect differences. It is also possible that the different BMI ranges across the studies may have accounted for some of the different results.
In this study group of overweight patients with BED, the degree of misreport of weight, height, and BMI were unrelated to measures of eating disorder psychopathology that was rigorously assessed with the EDE interview. These findings contrast those recently reported by Meyer et al. (8) in a study of a nonclinical sample of female university students assessed with the self-report version of the EDE (i.e., EDE questionnaire). It should be noted that the current sample of treatment-seeking adults was, on average, ≥20 years than the participants in the Meyer et al. study (8), which consisted of a university sample. Therefore, the difference in age across the two samples may account for some of the conflicting results between the two studies. We also found that misreport was not associated with measures of depression or self-esteem. These findings support and extend those of Masheb and Grilo (7) who found no significant relationships between accurate and inaccurate reporters in eating disorder psychopathology among obese individuals with BED. The current findings also parallel those of White et al. (17) who found no significant associations between weight misreport and eating disorder features among extremely obese bariatric surgery patients.
This study has a number of strengths and limitations. Strengths include the relatively large size, inclusion of both men and women, and the rigorous assessment battery. Limitations include the relatively small percentage (18.1%) of nonwhite participants, and uncertain generalizability to nontreatment-seeking persons with BED. Future research should investigate the degree of misreport among overweight and obese samples with and without binge eating. With this context in mind, our study suggests that overweight patients with BED are reasonably accurate reporters of weight and height, and that the degree of misreport is not systematically related to eating disorder psychopathology or psychological variables such as depression or self-esteem. These findings suggest that research with BED that has relied on self-reported weight and height may not be as inaccurate or systematically skewed (or related to individual differences) as suggested by Meyer et al. (8) for certain other study groups. Nonetheless, it is of course critically important to obtain objective weight and height data whenever possible. Given the need for some types of studies to rely on self-reported values, continued research is indicated and should, for example, examine the relationships between weight and height misreport, and eating disorder features in diverse samples in order to better understand the usefulness of such self-reported data.
We were supported by grants from the National Institutes of Health (K24 DK070052, K23 DK071646, R01 DK49587, R01 DK073542, and R21 MH077290). No additional funding was received for the completion of this work.
The authors declared no conflict of interest.