One-hundred-ninety-five children (6–13y) were seen for a baseline visit. Baseline data for 162 participants have been reported elsewhere (Tanofsky-Kraff, et al., 2005
; Tanofsky-Kraff, et al., 2004
). Of the 195 study participants, 118 (60.5%) completed a follow-up assessment an average of 4.7 (SD, 1.2, range: 2.6–7.1) years later. Compared to those who did not return for a follow-up assessment, youth who completed a follow-up visit were older at baseline (M=10.38, SD=1.49 versus M=9.63, SD=1.63y, p
=.01), but did not significantly differ in sex, race or baseline BMI, prevalence of LOC eating, disordered eating, depressive, or anxiety symptoms. As described above, data were imputed for the 77 children who did not return for a follow-up assessment, and combined results from the imputed data are presented.
At baseline, no child met full or partial-syndrome criteria for a DSM-IV-TR eating disorder. Forty-six children (23.6%) reported having experienced LOC eating at least once in their lifetime. Of these participants, approximately half (n=22, 47.8%) experienced at least 1 recent LOC episode in the month prior to assessment. In terms of the types and number of episodes in the past month, nine children reported only objective binge episodes (eight reported 1 episode and one reported 4 episodes); eleven reported only subjective binge episodes (four children reported 1 episode, five reported 2 episodes, one reported 3 and one child reported 4 episodes); two youth reported 1 objective binge episode and 1 subjective binge episode in the prior month. Consistent with previously published data (Tanofsky-Kraff, et al., 2005
), youth with baseline LOC Ever had significantly higher baseline BMI, BMI-Z scores (Kuczmarski, et al., 2002
), disordered eating attitudes, and depressive symptoms (ps
<.01; ) compared to those who never experienced LOC. Compared to those without baseline LOC, youth with baseline LOC Ever also were significantly younger at follow-up (p
=.04) and continued to have significantly higher follow-up BMI, BMI-Z scores (Kuczmarski, et al., 2002
), and EDE global scores and restraint and shape and weight concern subscale scores (ps
Participant Characteristics at Baseline
Participant Characteristics at Follow-up.
Baseline LOC Eating as a Predictor of Follow-up Disordered Eating and Negative Affect
In simple models adjusting only for years between baseline and follow-up and the respective baseline subscale score, baseline LOC Ever was associated with greater follow-up EDE global, restraint, shape and weight concern (ps<.02). Even after adjusting for additional covariates (baseline age, sex, race/ethnicity, and BMI change) baseline LOC Ever predicted greater follow-up EDE global, restraint, shape and weight concern scores (ps≤.04, ). Baseline LOC Ever significantly predicted follow-up anxiety in both the simple model adjusting for only baseline anxiety and years between baseline and follow-up (p=.03) and in a model adjusting for all covariates (p=.05). Baseline LOC Ever did not predict follow-up eating concern or depressive symptoms in either model (ps>.48).
Figure 1 Baseline loss of control eating and follow-up disordered eating attitudes. Experiencing loss of control over eating ever at baseline predicted increases on the Eating Disorder Examination Restraint, Shape Concern and Weight Concern subscales at follow-up. (more ...)
Descriptive Information on Persistence of LOC Eating
The presence of LOC Ever at baseline was associated with more than a two-fold greater likelihood of reported LOC at follow-up (OR=2.35, 95% CI=1.10–5.01, p=.03). Among those reporting LOC Ever at baseline (n=46), 52.2% (n=24) reported persistent LOC eating in the month prior to follow-up assessment. In contrast, among those who did not report LOC Ever at baseline (n=149), only 30.9% (n=46) reported emergent LOC at follow-up; the majority of this group (69.1%; n=103) never reported LOC at either time. Of those endorsing LOC Ever at baseline, 47.8% (n=22) were resolved at follow-up. After adjusting for years between baseline and follow-up, baseline LOC Ever remained a significant predictor of follow-up LOC (OR=2.67, 95% CI=1.15–6.22, p=.02). When persistence was characterized in terms of number of LOC episodes in the past month, LOC episodes for the whole sample increased from baseline (M, SE=0.19, 0.04 episodes per month) to follow-up (M, SE=0.53, 0.16 episodes per month, p=.04). Similarly, among the 24 youth who endorsed baseline LOC Ever and follow-up LOC, the average number of LOC episodes significantly increased by 1.33 (SE=0.53) episodes per month between baseline (M, SE=0.79, 0.24) and follow-up (M, SE=2.12, 0.40, p=.01). Significant increases in number of LOC episodes continued to be observed after accounting for years between baseline and follow-up, both in the whole sample and just among those with persistent LOC (ps<.04).
Persistence of LOC Eating as a Predictor of Disordered Eating and Negative Affect
In simple models (only covariates of years between baseline and follow-up and respective baseline subscale) and in models accounting for all covariates, there were significant overall effects for LOC persistence (never LOC, resolved, emergent, persistent) for all four follow-up EDE subscales (all main effects ps<.004; global score in model adjusting for all covariates, F(3,143)=12.12, p<.001, ). In simple adjusted models, pairwise comparisons indicated that youth with persistent LOC had significantly higher scores than the never LOC group for EDE global score and all four EDE subscales (ps<.006), higher scores than the resolved group on EDE global score, eating concern and shape concern (ps<.02), and higher scores than the emergent LOC group on EDE global score (p=.04). Youth with emergent LOC had higher scores on EDE global and all four subscales compared to the never LOC group (ps<.02), and emergent LOC youth also had higher EDE eating concern than youth with resolved LOC (p=.02). These significant differences remained after accounting for all covariates (ps<.05).
Figure 2 A: Persistent loss of control eating and follow-up disordered eating. Eating Disorder Examination Global score at follow-up is shown. Children who reported ever experiencing loss of control at baseline and loss of control at follow-up (persistent) had (more ...)
In a simple adjusted model and a model accounting for all covariates, there was an overall main effect of LOC persistence on symptoms of depression (in model adjusting for all covariates, F(3,262)=3.11, p=.03, ). In a simple adjusted model, pairwise comparisons indicated that persistent LOC youth had higher follow-up depressive symptoms than the never LOC group (p=.03) and the resolved LOC group (p=.01). The same significant differences were observed when accounting for all covariates (ps<.05). LOC persistence showed non-significant trends for association with follow-up symptoms of anxiety in both the simple adjusted model (F(3,311)=2.44, p=.06) and after adjusting for all covariates (F(3, 300)=2.28, p=.08).
Development of Partial or Full-Syndrome BED
At follow-up, 9 (4.5%) participants met partial or full-syndrome criteria for BED (M, SE=5.7, 1.3 LOC episodes in the month prior to assessment, range: 4–15). A subset (60%) of EDE/SPEEI interviews for these participants were taped and co-rated to examine inter-rater reliability for presence of the partial and full BED diagnosis. Cohen’s kappa for the identification of partial or full syndrome BED was 1.00 (p<.001). In the model examining the development of partial or full-syndrome BED at follow-up, only baseline reports of LOC Ever served as a significant contributor (OR=10.8, 95% CI 1.3–88.1, p=.03), after accounting for all other variables in the model including BMI change, baseline symptoms of depression and anxiety, and all four EDE subscales at baseline. Since the sample of participants who developed BED was small, yielding a very wide confidence interval for the predictive value of LOC Ever, we re-analyzed the model removing all non-significant variables except years in the study (sex, race, baseline age, depressive, anxiety, and disordered eating symptoms, as BMI growth). Baseline reports of LOC Ever continued to serve as a significant predictor of BED (OR= 5.07, 95% CI 1.1–24.5, p=.04). This analysis suggested that youth who reported ever having experienced LOC at baseline were greater than five times more likely to develop partial or full-syndrome BED at follow-up.
Follow-up Exploratory Analyses
Secondary analyses were conducted to examine predictors of LOC onset at follow-up. To examine predictors of the dependent variable of follow-up LOC eating onset (presence versus absence), we conducted binary logistic regression analyses with only the subset of children who did not endorse baseline LOC Ever (n=149). The independent variables were baseline disordered eating attitudes (global, restraint, shape concern, or weight concern), depressive symptoms, or anxiety symptoms. The sets of covariates considered were years between baseline and follow-up alone, and then years between visits and baseline age (y), sex (male versus female), race/ethnicity (non-Hispanic Caucasian versus other), and BMI change between baseline and follow-up. In the subset of children who reported no LOC Ever at baseline, neither disordered eating attitudes, nor symptoms of depression or anxiety predicted follow-up emergent LOC eating in any model (ps>.28).
To further explore the nature of the significant relationships observed between persistence of LOC and increases in disordered eating and negative affect, we conducted a series of follow-up linear multiple regressions regressing the dependent variables of change scores (follow-up minus baseline) in disordered eating (EDE global score, restraint, eating, shape concern, and weight concern subscales), depressive symptoms, or anxiety symptoms on the independent variables of change score in LOC eating episodes in the past month. In both simple adjusted models accounting only for years between baseline and follow-up, and in models accounting for all covariates, there was no significant association between change in number of LOC episodes and any of the dependent variables (all ps>.50).