Weight Suppression as Predictor of Bulimic Syndromes
Weight suppression may be a reliable indicator of severity in bulimic syndromes.
Weight suppression (WS), the difference between a person's highest body weight and current body weight, measured in pounds, is associated with clinical impairment in patients with bulimia nervosa, as reported in a study published in the International Journal of Eating Disorders.
Researchers from the Department of Psychology at the University of Kansas in Lawrence sought to clarify the relationship between WS and bulimia, believing that using WS as a criterion could help categorize the severity of an eating disorder. "Given that previous research has not tested whether WS explains bulimic-syndrome impairment, the goal of the present study was to address this gap...by testing the incremental validity in WS in explaining clinical impairment above-and-beyond other proposed indicators of bulimic-syndrome impairment," Kelsie T. Forbush, PhD, lead researcher of the study, and colleagues wrote.
This study included 101 adult participants, 83.1% of whom were female. Trained clinicians diagnosed participants with either full-threshold (n = 51) or subthreshold (n = 50) bulimia nervosa, using semistructured interviews. Participants were then asked to complete a 16-item self-report questionnaire, using a 4-point Likert scale. The goal of this assessment was to determine the degree to which symptoms of eating disorder affected the participant's functioning in the 28 days before completing the questionnaire. "Internal consistency for the [Clinical Impairment Assessment] was excellent in this study," the author confirmed.
The results of this study were mixed: researchers were able to prove a significant association between WS and eating disorder-related impairment in bulimic syndromes. "The independent association of WS and [eating disorder]-related clinical impairment represented a medium-size effect," the authors wrote.
However, the researchers found that WS could not significantly explain eating disorder-related clinical impairment more than other factors such as body mass index, frequency of inappropriate compensatory behaviors (ICBs), lifetime history of internalizing disorder, and multiple purging. "Our nonsignificant finding may be explained by the shared variance of ICB frequency and WS in explaining clinical impairment," the authors wrote. "The significant and positive correlation between ICB frequency and WS suggests that persons higher in WS engage in more ICBs, perhaps in an effort [to] maintain their suppressed weight." When ICB frequency was removed from this study, WS emerged as a significant explainer of bulimic syndrome impairments.
"While caution must be taken to not imply causality due to the cross-sectional nature of our data, our findings provided preliminary evidence that WS explains a significant amount of variance in bulimic-syndrome impairment," the authors wrote. "[I]nquiring about WS during routine clinical assessment for EDs could be informative."
Hagan KE, Clark KE, Forbush KT. Incremental validity of weight suppression in predicting clinical impairment in bulimic syndromes [published online January 17, 2017]. Int J Eat Disord. doi: 10.1002/eat.22673