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ABSTRACT Objective We examined the association between the genetic and environmental factors contributing to the liability to having ever engaged in self-induced vomiting (SIV initiation) and the genetic and environmental factors contributing to regular SIV behaviors (weekly or daily) for weight control. Method SIV was assessed in 3,942 women from monozygotic twin pairs and 2,790 women from same-sex dizygotic twin pairs, aged 20-47, from the Swedish Twin study of Adults: Genes and Environment. A causal-contingent-common pathway model assessed the extent to which genetic and environmental factors that influence initiation of SIV also influence regular SIV behaviors. Results In the best-fit model, genetic and individual-specific environmental factors influenced liability to SIV initiation. The genetic factors influencing regular SIV behaviors were the same as the genetic factors influencing SIV initiation. Additional individual-specific environmental factors that were unrelated to SIV initiation influenced regular SIV behaviors. Discussion Our findings provide evidence that the underlying liabilities for SIV initiation and regular SIV lie on the same continuum given the degree of overlap in risk between SIV initiation and regular SIV behaviors. Further, the lack of specific genetic factors and the importance of individual-specific environmental factors for regular SIV behaviors highlight the significance of environmental factors in the etiology of eating disorder symptomatology and the non-deterministic nature of genetic factors. Finally, our results suggest that when it comes to preventing individuals from developing regular SIV behavior, intervening at an environmental level is warranted. © 2015 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:421-427) [ABSTRACT FROM AUTHOR]

ABSTRACT Objective This study explored the cross-sectional and predictive effect of drive for thinness and/or negative affect scores on the development of self-reported anorexia nervosa (AN) and bulimia nervosa (BN). Method K-means were used to cluster the Eating Disorder Inventory-Drive for Thinness (DT) and Child Behavior Checklist Anxious/Depressed (A/D) scores from 615 unrelated female twins at age 16-17. Logistic regressions were used to assess the effect of these clusters on self-reported eating disorder diagnosis at ages 16-17 ( n = 565) and 19-20 ( n = 451). Results DT and A/D scores were grouped into four clusters: Mild (scores lower than 90th percentile on both scales), DT (higher scores only on DT), A/D (higher scores only on A/D), and DT-A/D (higher scores on both the DT and A/D scales). DT and DT-A/D clusters at age 16-17 were associated cross-sectionally with AN and both cross-sectionally and longitudinally with BN. The DT-A/D cluster had the highest prevalence of AN at follow-up compared with all other clusters. Similarly, an interaction was observed between DT and A/D that predicted risk for AN. Discussion Having elevated DT and A/D scores may increase risk for eating disorder symptomatology above and beyond a high score on either alone. Findings suggest that cluster modeling based on DT and A/D may be useful to inform novel and useful intervention strategies for AN and BN in adolescents. © 2015 Wiley Periodicals, Inc. (Int J Eat Disord 2015; 48:692-699) [ABSTRACT FROM AUTHOR]

Objective: Early maturing girls are at increased risk for disordered eating. However, it is unclear if the association between puberty and disordered eating continues throughout pubertal development and if a similar association is exhibited in boys. Method: Participants included 1340 same- and 624 opposite-sex twins from the Swedish Twin Study of Child and Adolescent Development. Pubertal development was assessed at age 13-14 with the pubertal development scale. General disordered eating, measured with the eating disorder inventory-2 (EDI) was assessed at age 16-17, and dieting and purging behaviors were assessed at both ages 16-17 and 19-20. We applied analysis of variance and logistic regression analyses to determine whether pubertal development in early-to-mid adolescence predicted eating disorder-related behaviors in late adolescence and young adulthood. Results: Pubertal development in early-to-mid adolescence was significantly associated with EDI scores and dieting in late adolescence. No significant association was observed between pubertal development and dieting and purging in young adulthood. Discussion: Complex combinations of cultural and biological influences likely converge during pubertal development increasing vulnerability to disordered eating. The impact of pubertal development on disordered eating appears to be limited to the adolescent period. © 2012 by Wiley Periodicals, Inc. (Int J Eat Disord 2012;45:819-826) [ABSTRACT FROM AUTHOR]

Objective: We examined the association among current self-reported sleep problems, lifetime binge eating (BE), and current obesity in women from the Swedish Twin study of Adults: Genes and Environment. Method: Logistic regression analyses were used to evaluate these associations in 3,790 women aged 20-47 years. Results: BE was reported by 244 (6.4%) women and was positively associated with not getting enough sleep ( p < .015), sleeping poorly ( p < .001), problems falling asleep ( p < .001), feeling sleepy during work or free time ( p < .001), and disturbed sleep ( p < .001). These same sleep variables, as well as napping and being a night person, were also significantly associated with obesity. The associations between BE and sleep remained after accounting for obesity. Discussion: This investigation offers empirical support for an independent association between sleep problems and BE, which is likely due to complex psychological, biological, neuroendocrine, and metabolic factors. © 2012 by Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objective: We assessed the impact of reducing the binge eating frequency and duration thresholds on the diagnostic criteria for bulimia nervosa (BN) and binge eating disorder (BED). Method: We estimated the lifetime population prevalence of BN and BED in 13,295 female twins from the Swedish Twin study of Adults: Genes and Environment employing a range of frequency and duration thresholds. External validation (risk to cotwin) was used to investigate empirical evidence for an optimal binge eating frequency threshold. Results: The lifetime prevalence estimates of BN and BED increased linearly as the frequency criterion decreased. As the required duration increased, the prevalence of BED decreased slightly. Discontinuity in cotwin risk was observed in BN between at least four times per month and at least five times per month. This model could not be fit for BED. Discussion: The proposed changes to the DSM-5 binge eating frequency and duration criteria would allow for better detection of binge eating pathology without resulting in a markedly higher lifetime prevalence of BN or BED. © 2011 by Wiley Periodicals, Inc. (Int J Eat Disord 2012) [ABSTRACT FROM AUTHOR]