Prevalence and Demographics
A total of 67 of 917 individuals (7.2% of the total sample) screened positive for Binge Eating Disorder, as assessed by the PHQ, but 7 of those subjects reported symptoms of bulimia and were excluded from the analyses. This results in a final sample size of 910 and a sample prevalence of 6.6% for positive screens on the BED section of the PHQ. Demographic make-up of the sample was: 55% female and 45% male; 15% African-American/Black, 82% Caucasian/White and 3% other race/ethnicity; mean age was 44 years (SD=14, median 46). Due to differential response rates among demographic groups, our sample is slightly under-representative of males (48 % targeted vs. 45% recruited), African-Americans (20% targeted vs. 15% recruited), and persons aged 18–34 (29% targeted vs. 24% recruited). The demographic distribution of BED is presented in . There were no significant differences between BED+ and BED− groups; males and females report BED symptoms in nearly equal proportions.
Association with BMI
presents the prevalence of BED in four BMI categories, using standard cutoffs (25 and below for normal/underweight, 30 for obesity, 40 for morbid obesity). There is a strong association between weight category and BED (χ2=47.7, df=3, p<0.001). Nearly 70% of BED+ subjects report BMI of 30 and above, whereas slightly fewer than 30% of BED− participants reported comparable BMIs. The mean BMI for BED+ individuals was 34.1, contrasted with a mean BMI of 27.8 for BED− subjects. After adjusting for sociodemographic variables, the between-class BMI difference was 6.3 units (F=61.4, p<0.001).
BMI Categories for PHQ-BED+ versus PHQ-BED− Subjects
Association with Psychiatric Outcomes
The association of BED with other common psychiatric syndromes is presented in . Highly significant associations were seen with major depression, generalized anxiety disorder, panic attacks, and a history of one or more suicide attempts. A marginal association was seen with nicotine dependence and a trend was observed with probable alcohol use disorder. Obesity without BED (Obesity+/BED−) exhibited no significant association with these outcomes. For depression, generalized anxiety disorder, panic attacks, and probable alcohol use disorder, the association with BED was significantly stronger than that for obesity only. Interestingly, there was a significant difference between the BED+ group and the Obesity+/BED− group in the odds for probable alcohol use disorder, although neither effect was significant relative to the comparison group. The Obesity+/BED−group exhibited a trend toward lower odds for probable alcohol use disorder; apparently this trend is countered by BED such that BED+ individuals had significantly higher odds for probable alcohol use disorder than obese individuals without BED symptomatology.
Odds-ratios for the Prediction of Psychiatric Problems from PHQ-BED, or Obesity.
Health-Related Quality of Life
Mean values for health-related quality of life scores, as measured by the SF-12 questionnaire, are presented in . Scores for Obesity−/BED−participants were compared to those for the Obesity+/BED− and the BED+ group. BED+ individuals scored substantially lower on the Mental Health Summary scale (MHS) than did the Obesity−/BED− group or the Obesity+/BED− group. The effect was significant after adjusting for sociodemographic factors (β=−0.73, F=32.8, p<0.001). Moreover, the effect remained significant after adjusting for all psychiatric syndromes listed in in addition to sociodemographic variables (β=−0.38, F=8.5, p=0.004). Notably, obesity without BED exhibited no effect on MHS score. On the Physical Health Summary scale (PHS), both Obesity+/BED− subjects and BED+ subjects scored lower than the Obesity−/BED− group (β=−0.48, F=50.0, p<0.001 for obesity only, β=−0.65, F=28.6, p<0.001 for BED, adjusting for sociodemographic variables). But Obesity+/BED− and BED+ groups did not differ from each other (F=1.6, p=0.20), suggesting that decreased PHS scores are likely to be attributable to obesity, rather than BED symptoms. After adjusting for psychiatric syndromes, neither PHS effect remained significant.
Mean SF-12 Scores for PHQ-BED+ Versus PHQ-BED− Subjects, With and Without Obesity
Mean personality scores for each of the three groups (BED+, Obesity+/BED− and Obesity−/BED−) are presented in . Statistical tests (ANCOVA) included sociodemographic variables as covariates. The BED+ group scored significantly higher on Novelty Seeking then either of the other two groups. Likewise, low Self-Directedness and low Cooperativeness were associated with BED, but not with obesity alone. Harm Avoidance scores were elevated for both Obesity+/BED− individuals and for the BED+ group, but the former effect was small and the BED+ group scored significantly higher than the obesity only group. Both the obesity-only group and the BED+ group scored slightly lower in Persistence compared to the Obesity−/BED− group.
TCI Personality Scale Scores for PHQ-BED+ Versus PHQ-BED− Subjects, With and Without Obesity