Descriptive Statistics. The majority of participants had parents who were married (64.0%) and who had at least some post-secondary education (68.1% for fathers and 69.8% for mothers). Most participants (94.7%) reported having experienced menarche. Study groups (i.e., ED, DD, and control) did not differ in terms of age, pubertal status, parental relationship status, mother’s level of education, or father’s level of education. Within the ED group, participants with anorexia and bulimia did not differ from each other in terms of RSE scores (t(22) = 0.42, p > 0.65), BDI-II scores (t(23) = −0.93, p > 0.35), or BRSC (t(23) = −1.07, p > 0.25). Thus, these participants were kept in a single group (i.e., ED group) for analyses.
Ethnicity differed across the three study groups (χ2(8, n = 75) = 31.00, p ≤ 0.001). Within the ED group, the majority of adolescents (n = 20, 80%) were Caucasian, 4 (16%) were Hispanic, and 1 (4%) identified herself as “other”. Within the DD group, the majority of adolescents (n = 12, 48%) were Caucasian, 10 (40%) were African American, 2 (8%) were Asian, and 1 (4%) was Hispanic. Finally, within the healthy control group, the majority of adolescents (n = 15, 60%) were Caucasian, 6 (24%) identified themselves as “other”, and 4 (16%) were African American. Although ethnicity differed across groups, results of this study are unlikely to be confounded by ethnicity. ANOVA analyses revealed that ethnicity did not have an effect on BRSC (p > 0.15) or any of the EDI-2 subscales (p > 0.15).
displays descriptive statistics and ANOVA results for BMI z-scores, EDI-2 scores, BDI-II scores, and RSE scores across diagnostic groups. As expected, an ANOVA on BMI z-scores was significant (F(2, 69) = 12.30, p ≤ 0.001, ηp2 = 0.26). Tukey’s HSD post-hoc comparisons revealed that adolescents in the ED group had significantly lower BMI z-scores than adolescents in the DD group (p ≤ 0.001) and healthy control group (p ≤ 0.05). Also as expected, a Multivariate ANOVA on EDI-2 scores was significant (F(2, 72) = 6.152, p ≤ 0.001, ηp2 = 0.21). Post-hoc comparisons revealed that adolescents in the ED group had significantly higher scores on Drive for Thinness and Bulimia than adolescents in the healthy control (p ≤ 0.001 for both DT and B) and DD groups (p ≤ 0.001 for DT, p ≤ 0.05 for B). In regards to Body Dissatisfaction, adolescents in the ED group had significantly higher scores than adolescents in the healthy control group (p ≤ 0.001) only; Body Dissatisfaction scores did not differ across the ED and DD groups. Also as expected, an ANOVA revealed that BDI-II scores differed across groups (F(2, 72) = 14.80, p ≤ 0.001, ηp2 = 0.29). Post-hoc comparisons revealed that adolescents in both the ED and DD group had significantly greater BDI-II scores than adolescents in the healthy control group (p ≤ 0.001 for both comparisons). BDI-II scores did not differ across the ED and DD groups. Finally, and also as expected, an ANOVA revealed that RSE scores differed across groups (F(2, 70) = 11.62, p ≤ 0.001, ηp2 = 0.25). Post-hoc comparisons revealed that adolescents in both the ED and DD group displayed significantly greater RSE scores than adolescents in the healthy control group (p ≤ 0.001 for both comparisons).
| Table 1Descriptive Statistics and ANOVA Results for Body Mass Index, Eating Disorder Inventory-2 scores, Beck Depression Inventory-II scores, and Rosenberg Self-Esteem Scale Scores. |
Body-Related Social Comparison. As hypothesized, groups differed in terms of BRSC (F(2, 71) = 8.23, p ≤ 0.001, ηp2 = 0.19). Tukey’s HSD post-hoc comparisons revealed that participants in the ED group (M = 4.20, 95% CI [3.80, 4.60], range = 3) reported significantly higher BRSC scores than participants in the DD group (M = 3.44, 95% CI [2.92, 3.96], range = 4; p ≤ 0.05) and healthy control group (M = 3.00, 95% CI [2.63, 3.37], range = 4; p ≤ 0.001). No significant difference in BRSC was found between the DD and healthy control group.
displays correlations among study variables (i.e., BRSC, EDI-DT, EDI-B, EDI-BD, BDI-II, and RSE). As shown, BRSC is significantly positively correlated with scores on the EDI-DT (r = 0.64, p ≤ 0.01), EDI-B (r = 0.42, p ≤ 0.01), and EDI-BD (r = 0.66, p ≤ 0.01).
| Table 2Correlation Matrix for Study Variables. |
displays the results of the regression analyses on each of the three EDI-2 subscales. These regression analyses revealed that BRSC was a significant predictor of Drive for Thinness (β = 0.48, p ≤ 0.001), Bulimia (β = 0.29, p ≤ 0.05), and Body Dissatisfaction (β = 0.54, p ≤ 0.001), even after controlling for RSE and BDI-II scores. Over and above the variance predicted by RSE and BDI-II scores, BRSC predicted an additional 17% (p ≤ 0.001), 6% (p ≤ 0.05), and 21% (p ≤ 0.001) of the variance in Drive for Thinness, Bulimia, and Body Dissatisfaction, respectively.
| Table 3Summary of Three Separate Hierarchical Regression Analyses for the Prediction of Scores on EDI-2 Subscales. |