Klump, K. L., A. Holly, et al. (2000). "Physical similarity and twin resemblance for eating attitudes and behaviors: A test of the equal environments assumption." Behavior Genetics 30(1), 51-58.
The degree of physical similarity (general appearance, body size/shape) among a set of twins does not predict the degree of similarity for the pair's eating behaviors and attitudes.
Keel, P.K., Klump, K.L., Miller, K.B., McGue, M. & Iacono, W.G. (2005). "Shared Transmission of Eating Disorders and Anxiety Disorders." International Journal of Eating Disorders, 38, 99-105.
When only one member in a set of identical twins has an eating disorder, the co-twin who does not have an eating disorder is more than twice as likely to suffer from an anxiety disorder. The non-eating disordered twin is also significantly more likely to suffer from major depression and nicotine dependence.
Marmorstein, N.R., Von Ranson, K.M., Iacono, W.G. & Succop, P.A. (2007). Longitudinal Associations Between Externalizing Behavior and Dysfunctional Eating Attitudes and Behaviors: A Community-Based Study. Journal of Clinical Child and Adolescent Psychology, 36, 87-94.
Across ages 11, 14, and 17, girls' externalizing behavior (e.g., aggressiveness, impulsivity) predicts, and is predicted by, increases in eating disorder behaviors and attitudes (weight preoccupation, body dissatisfaction and the use of inappropriate compensatory behaviors).
Sherman, D.K., Iacono, W.G., & Donnelly, J.M. (1995). Development and validation of body rating scales for adolescent females. International Journal of Eating Disorders, 18, 327-333.
- OBJECTIVE: This present study was designed to develop and validate rating scales for body image assessment in adolescents.
METHOD: The figures of the Figure Rating Scale (FRS; Stunkard, Sorenson, & Schlusinger, The genetics of neurological and psychiatric disorders, 1983, pp. 115-129) used in previous research seem more appropriate for research with adults. Accordingly, we developed two forms of a body rating scale (BRS) depicting adolescent females and administered these scales and the FRS to 315 female subjects. The subjects comprise three age groups, 11-year-olds, 17-year-olds, and their mothers, all participants in the epidemiologically based Minnesota Twin Family Study. Two independent observers also rated each subject.
RESULTS: Intercorrelations among raters and scales and with body mass index were generally high and indicate comparability between the BRS measures and the FRS.
DISCUSSION: The generally excellent psychometric properties of the new scales coupled with their face validity may make them a useful tool for body image research in children and adolescents.
Klump, K.L., Holly, A., Iacono, W.G., McGue, M., & Wilson, L.E. (2000). Physical similarity and twin resemblance for eating attitudes and behaviors: A test of the equal environments assumption. Behavior Genetics, 30, 51-58.
- The Equal Environments Assumption (EEA) in twin studies of eating pathology was investigated by examining the hypothesis that twin resemblance for eating attitudes and behaviors is affected by their degree of physical similarity. Eating attitudes and behaviors were assessed in 338 female adolescent twin pairs with a revised version of the Eating Disorder Inventory (EDI). General physical similarity as well as body size/shape similarity were assessed using ratings of color photographs, ratings of body shape, and body mass index. All physical similarity assessments were conducted blind to twin zygosity. Significant associations between physical similarity and twin similarity for eating attitudes and behaviors were not found. Mean EDI within-twin pair absolute difference scores did not differ significantly among more versus less physically-similar groups. Additionally, correlation and regression analyses failed to find a significant association between EDI absolute difference scores and physical similarity indices. The current findings provide support for the EEA in twin studies of eating attitudes and behaviors.
Klump, K.L., McGue, M., & Iacono, W.G. (2000). Age differences in genetic and environmental influences on eating attitudes and behaviors in preadolescent and adolescent female twins. Journal of Abnormal Psychology, 109, 239-251.
- A sample of 680 11- and 602 17-year-old female twins was used to examine (a) age differences in genetic and environmental influences on disordered eating attitudes and behaviors and (b) associations between body mass index (BMI) and eating attitudes and behaviors. Univariate, biometrical model-fitting analyses indicated that 11-year-old twins exhibited less genetic and greater shared environmental influence on eating attitudes and behaviors than 17-year-old twins. Bivariate model-fitting analyses indicated that the relationship between BMI and eating attitudes was mediated primarily by common shared environmental influences in 11-year-old twins and common genetic influences in 17-year-old twins. Nonetheless, the majority of genetic influences on eating attitudes and behaviors in older twins were due to genetic effects that are independent of those operating in BMI.
Klump, K.L., Miller, K.B., Keel, P.K., McGue, M., & Iacono, W.G. (2001). Genetic and environmental influences on anorexia nervosa syndromes in a population-based twin sample. Psychological Medicine, 31, 737-740.
- OBJECTIVE: The authors sought to derive heritability estimates for anorexia nervosa and to explore the etiology of the comorbid relationship between anorexia nervosa and major depression. METHOD: They applied bivariate structural equation modeling to a broad definition of anorexia nervosa and lifetime major depression as assessed in a population-based sample of 2,163 female twins. RESULTS: Anorexia nervosa was estimated to have a heritability of 58% (95% confidence interval=33%–84%). The authors were unable to completely rule out a contribution of shared environment. The comorbidity between anorexia nervosa and major depression is likely due to genetic factors that influence the risk for both disorders. CONCLUSIONS: Although the study was limited by the small number of affected twins, the results suggest that genetic factors significantly influence the risk for anorexia nervosa and substantially contribute to the observed comorbidity between anorexia nervosa and major depression.
Klump, K.L., McGue, M., & Iacono, W.G. (2002). Genetic relationships between personality and eating attitudes and behaviors. Journal of Abnormal Psychology, 111, 380-389.
- Genetic and environmental factors underlying relationships between personality traits and disordered eating were examined in 256 female adolescent twin pairs (166 monozygotic, 90 dizygotic). Eating behaviors were assessed with the Total Score, Body Dissatisfaction, Weight Preoccupation, Binge Eating, and Compensatory Behavior subscales from the Minnesota Eating Disorders Inventory (M-EDI; K. L. Klump, M. McGue, & W. G. Iacono, 2000). Personality characteristics were assessed with the Negative Emotionality, Positive Emotionality, and Constraint scales from the Multidimensional Personality Questionnaire (MPQ; A. Tellegen, 1982). Model-fitting analyses indicated that although genetic factors were more likely to contribute to MPQ and M-EDI phenotypic associations than environmental factors, shared genetic variance between the 2 phenotypes was limited. MPQ personality characteristics may represent only some of several genetic risk factors for eating pathology.
Von Ranson, K.M., Iacono, W.G., & McGue, M. (2002). Disordered eating and substance use in an epidemiological sample: I. Associations within individuals. International Journal of Eating Disorders, 31, 389-403.
- OBJECTIVE: This study examined the strength of associations between disordered eating and eating disorders and substance use and substance use disorders (SU/SUDs) in an epidemiological sample. METHODS: 672 adolescent girls and 718 women completed structured interviews of lifetime eating disorders and substance use and misuse, as well as self-reported current disordered eating attitudes and behaviors. RESULTS: Although effect sizes were small, eating attitudes and disorders were associated modestly with nicotine, alcohol, and drug use, and with nicotine dependence in adolescent girls. Alcohol use and misuse were related to eating attitudes and pathology in women. SU/SUDs were associated with restricting and bulimic behaviors and no prominent differences in associations were observed between substance classes. In contrast to findings in clinical populations, these community-based results were positive but generally weak, suggesting there is no strong, overarching relationship between eating and substance use problems. DISCUSSION: These results have implications for the addiction model of eating disorders.
Klump, K.L., McGue, M. & Iacono, G. (2003). Differential heritability of eating attitudes and behaviors in prepubertal and pubertal twins. International Journal of Eating Disorders, 33, 287-292.
- OBJECTIVE: Differential heritability of eating pathology in prepubertal, pubertal, and 17-year-old twins was examined using a population-based twin sample. METHOD: Participants included 530 11-year-old (452 prepubertal, 78 pubertal twins) and 602 17-year-old female twins from the Minnesota Twin Family Study. Puberty was assessed with the Pubertal Development Scale, and general eating pathology was assessed with the total score from the Minnesota Eating Disorders Inventory (M-EDI). RESULTS: M-EDI total score intraclass correlations for the pubertal 11-year-old group were more similar to the 17-year-old twins' than the prepubertal 11-year-old twins, suggesting similar levels of genetic influence in the pubertal and older adolescent cohort. Model-fitting corroborated these impressions, indicating that genetic factors accounted for 0% of the variance in 11-year-old prepubertal twins but 54% of the variance in 11-year-old pubertal and 17-year-old twins. DISCUSSION: Findings suggest that a portion of the genetic influence on eating pathology may become activated during puberty.
Von Ranson, K.M., McGue, M., & Iacono, W.G. (2003). Disordered eating and substance use in an epidemiological sample: II. Associations within families. Psychology of Addictive Behavior, 17, 193-201.
- This study investigated familial associations of disordered eating (DE) with substance use and substance use disorders (SU/SUDs) in a community-based sample of 620 adolescent girls, their 310 mothers, and 299 fathers. Female participants completed structured interviews of lifetime anorexia nervosa, bulimia nervosa, binge eating disorder, and SU/SUD; daughters also completed a self-report measure of current DE attitudes and behaviors. Fathers completed interviews assessing lifetime SUD. Evaluation of independent and combined associations of mothers' bulimic eating disturbance (ED) and parents' SUDs with daughters' DE/EDs and SU/SUDs revealed links between mothers' ED and daughters' DE but no relationship between EDs and SU/SUDs across generations. These results suggest that these problems are not cross-transmitted within families and suggest that the addiction model of eating disorders may be simplistic.
Keel, P. K., Klump, K. L., Miller, K. B., McGue, M., & Iacono, W. G. (2005). Shared transmission of eating disorders and anxiety disorders. International Journal of Eating Disorders, 38, 99-105.
- Objective Eating disorders have high comorbidity with mood, anxiety, and substance use disorders. Using twins from the population-based Minnesota Twin Family Study (MTFS), we examined comorbidity and shared transmission between eating pathology and these disorders. Method Female twins (N = 672), ages 16–18 years, completed structured clinical interviews assessing anorexia nervosa and bulimia nervosa (as described in the 4th ed. of the Diagnostic and Statistical Manual of Mental Disorders [DSM-IV; American Psychiatric Association, 1994]), as well as mood, anxiety, and substance use disorders (as described in the 3rd Rev. ed. of the Diagnostic and Statistical Manual of Mental Disorders [DSM-III-R]). Shared transmission was examined using a discordant monozygotic (MZ) twin design. Results Significant comorbidity was found between eating disorders and major depression, anxiety disorders, and nicotine dependence. Within MZ twin pairs discordant for eating disorders (n = 14), non–eating-disordered cotwins demonstrated increased risk for anxiety disorders compared with controls. Similarly, within MZ twin pairs discordant for anxiety disorders (n = 52), non–anxiety-disordered cotwins demonstrated increased risk for eating disorders compared with controls. Discussion Findings support shared transmission between eating disorders and anxiety disorders. However, the nature of this shared diathesis remains unknown.
Perkins, P.S., Klump, K.L., Iacono, W.G., & McGue, M. (2005). Personality traits in women with anorexia nervosa: Evidence for a treatment-seeking bias? International Journal of Eating Disorders, 37, 32-37.
- OBJECTIVE: Several personality traits have been associated with anorexia nervosa (AN) in treatment-seeking samples of patients. The current study used a population-based sample to compare the personality characteristics of women with AN who sought treatment versus those who did not. METHOD: Participants included 27 (14 treatment-seekers, 13 non-treatment-seekers) women with threshold or subthreshold AN and 273 (64 treatment seekers, 209 non-treatment seekers) comparison women from the Minnesota Twin Family Study. Personality was assessed with the higher-order factors and primary scales of the Multidimensional Personality Questionnaire (MPQ). RESULTS: Non-treatment-seeking women showed lower levels of negative emotionality, stress reaction, and alienation than treatment-seeking women. DISCUSSION: These results suggest that personality deviations may be overestimated in treatment-seeking samples.
Von Ranson, K.M., Klump, K.L., Iacono, W.G., & McGue, M. (2005). The Minnesota Eating Behavior Survey: A brief measure of disordered eating attitudes and behaviors. Eating Behaviors, 6, 373-392.
- This article describes details of the development and psychometric characteristics of a brief self-report inventory for assessing attitudes and behaviors symptomatic of eating disorders that is currently in use in a longitudinal study of over 700 families with 11-year-old or 17-year-old twin girls. The Minnesota Eating Behavior Survey (MEBS), formerly the Minnesota Eating Disorder Inventory, is a 30-item measure developed for use with children as young as 10 years as well as adults. An examination of the MEBS's psychometric properties in a large, community sample of girls, women, and men demonstrated good factor congruence, internal consistency reliability, three-year stability, as well as evidence of concurrent and criterion validity. This questionnaire has promise as a screening and assessment measure for eating disturbance in cross-sectional and longitudinal research involving individuals of a wide range of ages.
Klump, K.L., Burt, S.A., McGue, M., & Iacono, W.G. (2007). Changes in genetic and environmental influences on disordered eating across adolescence: A longitudinal twin study. Archives of General Psychiatry, 64, 1409-1415.
- Context Previous research suggests substantial increases in genetic effects on disordered eating across adolescence. Unfortunately, these studies were cross-sectional and focused primarily on early (age 11 years) vs late (age 17 years) adolescence. Objective To examine longitudinal changes in genetic and environmental influences on disordered eating across early, mid, and late adolescence. Design and Setting Population-based study of female same-sex twins. Participants Seven hundred seventy-two female adolescent twins from the Minnesota Twin Family Study assessed at ages 11, 14, and 18 years. Main Outcome Measures Disordered eating symptoms (ie, body dissatisfaction, weight preoccupation, binge eating, and the use of compensatory behaviors) were assessed with the total score from the Minnesota Eating Behavior Survey. Results Biometric model-fitting indicated significant changes in genetic and shared environmental effects across early to mid adolescence. Although genetic factors accounted for a negligible proportion (6%) of variance at age 11 years, genes increased in importance and accounted for roughly half of the variance (46%) in disordered eating at ages 14 and 18 years. Shared environmental influences decreased substantially across these same ages. Conclusions Findings highlight the transition from early to mid adolescence as a critical time for the emergence of a genetic diathesis for disordered eating. The increase in genetic effects during this developmental stage corroborates previous research implicating puberty in the genetic etiology of eating disorders.
Klump, K.L., Perkins, P.S., Burt, S.A., McGue, M., & Iacono, W.G. (2007). Puberty moderates genetic influences on disordered eating. Psychological Medicine, 37, 627-634.
- BACKGROUND: Previous research suggests that genetic influences on disordered eating may be greater in pubertal than pre-pubertal girls. Although these findings are consistent with pubertal activation of genetic influences on disordered eating, earlier studies were unable to directly test this hypothesis. The purpose of the present study therefore was to directly examine this possibility by investigating whether pubertal development moderates genetic influences on disordered eating. METHOD: Participants were 510 female adolescent twins from the Minnesota Twin Family Study. Disordered eating was measured with the Total Score of the Minnesota Eating Behavior Survey, while pubertal status was assessed with the Pubertal Development Scale. RESULTS: Consistent with our hypothesis, model-fitting indicated significant increases in genetic influence on disordered eating with advancing pubertal development. CONCLUSIONS: These findings suggest that puberty influences the expression of genes for disordered eating.
Marmorstein, N.R., von Ranson, K.M., Iacono, W.G., & Succop, P.A. (2007). Longitudinal associations between antisocial behavior and dysfunctional eating attitudes and behaviors: A community-based study. Journal of Clinical Child and Adolescent Psychology, 36, 87-94.
- This study investigated longitudinal associations between externalizing behavior and dysfunctional eating attitudes and behaviors. Participants were girls drawn from the community-based Minnesota Twin Family Study and assessed at ages 11, 14, and 17. Cross-sectional correlations indicated that the strength of the associations between externalizing behavior and dysfunctional eating attitudes and behaviors increased over time. Mixed-model analyses indicated that earlier externalizing behavior predicted increases in weight preoccupation, body dissatisfaction, and use of inappropriate compensatory behaviors. Earlier use of inappropriate compensatory behaviors predicted increases in externalizing behavior.
Marmorstein, N.R., von Ranson, K.M., Iacono, W.G., & Malone, S.M. (2008). Prospective associations between depressive symptoms and eating disorder symptoms among adolescent girls. International Journal of Eating Disorders, 41, 118-123.
- OBJECTIVE: Although eating disorders are frequently associated with depression, evidence regarding which problem predicts the other is conflicting, and little research has addressed the developmental course of this relation. This study examined longitudinal associations between depression and eating pathology across adolescence. METHOD: Participants were 754 girls participating in the community-based Minnesota Twin Family Study. Depressive symptoms and eating pathology were assessed at approximately ages 11, 14, and 17. RESULTS: As expected, substantial continuity in both eating pathology and depressive symptoms occurred across time. Analysis of cross-lag paths controlling for earlier levels of symptoms indicated that overall levels of eating pathology predicted later depressive symptoms from 11 to 14 and from 14 to 17. CONCLUSION: Adolescent girls with high levels of eating-related pathology appear to be at risk for later depression.
Culbert, K.M., Burt, S.A., McGue, M., Iacono, W.G., & Klump, K.L. (2009). Puberty and the genetic diathesis of disordered eating attitudes and behaviors. Journal of Abnormal Psychology, 118(4), 788-796. PMCID: PMC2782672
- Twin studies from the Minnesota Twin Family Study (MTFS) suggest negligible genetic effects on eating pathology before puberty but increased genetic effects during puberty. However, an independent study found no pubertal differences in genetic and environmental effects (R. Rowe, A. Pickles, E. Simonoff, C. M. Bulik, & J. L. Silberg, 2002). Discrepant results may be due to methodological differences. The MTFS studies divided twins at mid-puberty, whereas R. Rowe et al. (2002) divided twins based on menarche alone. In the present study, the authors aimed to reconcile discrepant findings by examining differences in etiologic effects for disordered eating attitudes and behaviors (i.e., levels of weight preoccupation, body dissatisfaction, binge eating, compensatory behaviors) using both classification methods in a new sample of 656 female twins. Using the MTFS method (i.e., K. L. Klump, M. McGue, & W. G. Iacono, 2003), the authors observed nominal genetic effects in prepubertal twins but significant genetic effects in pubertal and young adult twins. Conversely, genetic effects were moderate and equal in all groups using the R. Rowe et al. (2002) method. Findings highlight the potentially important role of puberty in the genetic diathesis of disordered eating attitudes and behaviors and the need to use early indicators of pubertal status in studies of developmental effects.
Klump, K.L., Suisman, J.L., Burt, S.A., McGue, M., & Iacono, W.G. (2009). Genetic and environmental influences on disordered eating: An adoption study. Journal of Abnormal Psychology, 118(4), 797-805. PMCID: PMC2805262
- Twin studies indicate significant genetic, but little shared environmental, influences on eating disorders. However, critics argue that study limitations constrain the conclusions that can be drawn. Adoption studies avoid many of these limitations, but to date, no adoption studies of eating pathology have been conducted. The current study was the first adoption study to examine genetic/environmental effects for disordered eating. Participants included 123 adopted and 56 biological female sibling pairs. Disordered eating (i.e., overall eating pathology, body dissatisfaction, weight preoccupation, binge eating) was assessed with the Minnesota Eating Behaviors Survey (Klump, McGue, & Iacono, 2000; von Ranson, Klump, Iacono, & McGue, 2005). Biometric model fitting indicated significant genetic influences (59%-82%) on all forms of disordered eating, with nonshared environmental factors accounting for the remaining variance. Shared environmental factors did not contribute significantly to any disordered eating symptom. Our findings bolster those from twin studies and provide critical evidence of significant genetic effects on disordered eating symptoms.