Genetic overlap between alcohol use disorder and bulimic behaviors in European American and African American women

A longitudinal test of problematic alcohol use and binge eating among college women: The moderating role of shame

Problematic alcohol use and binge eating frequently co-occur. High levels of negative affect, negative urgency, and/or shame may increase the likelihood that problematic alcohol use and binge eating co-occur over time.

OBJECTIVE

Examine 1) the temporal relationship between problematic alcohol use and binge eating among college women, who are at high risk for both, and 2) the additive and moderating effects of shared, emotion-based risk factors in models involving both problematic alcohol use and binge eating.

METHOD

In n = 302 college women assessed at two time points across 8 months, we used hierarchical linear regression to invstigate our objectives.

RESULTS

Baseline problematic alcohol use and baseline shame independently predicted increases in follow-up binge eating, controlling for baseline binge eating. In addition, the interaction between problematic alcohol use and shame accounted for further variance in subsequent binge eating (the influence of baseline problematic alcohol use on follow-up binge eating was stronger at higher levels of baseline shame). The reciprocal relationship was not significant: baseline binge eating did not predict follow-up problematic alcohol use independently or in conjunction with risk factors. Neither negative affect nor negative urgency showed predictive effects beyond prior behavior and shame. Results support 1) problematic alcohol use as a prospective risk factor for binge eating, 2) shame as an additive predictor of binge eating, and 3) shame as a positive moderator of binge eating prediction from problem drinking.

CONCLUSION

Addressing shame and problematic alcohol use may be warranted in binge eating interventions for college women.

Associations of broad eating disorder symptoms with later alcohol problems in Finnish adult twins: A nationwide 10-year follow-up

OBJECTIVE

Eating disorders are associated with subsequent alcohol problems, but it is not known whether this association also extends to broader eating disorder symptoms not captured by clinical diagnoses. We assessed the longitudinal association of broad eating disorder symptoms with alcohol problems in a nationwide twin sample (FinnTwin16).

METHODS

Finnish women (N = 1905) and men (N = 1449) self-reported their eating disorder symptoms using the Eating Disorder Inventory-2 Bulimia, Drive for Thinness, and Body Dissatisfaction subscales at the mean age of 24.4 years in 2000-2003. A subsample of participants also completed items on drive for muscularity, height dissatisfaction, and muscle-enhancing supplement use. Alcohol problems were assessed 10 years later at the age of 34.1 in 2010-2012 with the Rutgers Alcohol Problem Index.

RESULTS

Eating disorder symptoms were associated with later alcohol problems (odds ratio per point increase 1.02-1.18). Bulimia showed stronger associations among men than women (p for interaction .012). Drive for muscularity and height dissatisfaction were also associated with later alcohol problems, but supplement use was not. When accounting for baseline alcohol problems, only Bulimia (among women and men) and Drive for Thinness (among men) were significantly associated with later alcohol problems. Bulimia was also significantly associated with later alcohol problems in within-twin-pair analyses among dizygotic twins, but not among monozygotic twins.

DISCUSSION

In a longitudinal setting, eating disorder symptoms were associated with later alcohol problems. Bulimic symptoms were a stronger risk factor for men than women. These associations may be attributable to baseline alcohol problems, childhood environment and genetic liability.

PUBLIC SIGNIFICANCE

This study found that both young adult women and men with broad eating disorder symptoms are at a higher risk of alcohol-related problems than those without such symptoms. Men with bulimic symptoms were at a particularly high risk. These findings emphasize the need for better prevention and treatment of disordered eating, body image concerns and alcohol problems for both young adult women and men.

Differential genetic associations between dimensions of eating disorders and alcohol involvement in late adolescent twins

BACKGROUND

Twin studies have demonstrated shared genetic and environmental effects between eating disorders and alcohol involvement in adults and middle adolescents. However, fewer studies have focused on late adolescents or investigated a wide range of eating disorder dimensions and alcohol involvement subscales in both sexes. We examined genetic and environmental correlations among three eating disorder dimensions and two alcohol involvement subscale scores in late adolescent twins using bivariate twin models.

METHODS

Participants were 3568 female and 2526 male same-sex twins aged 18 years old from the Child and Adolescent Twin Study in Sweden. The Eating Disorder Inventory-2 (EDI) assessed the drive for thinness, bulimia, and body dissatisfaction. Alcohol involvement was assessed with the Alcohol Use Disorder Identification Test consumption (AUDIT-C) and problem (AUDIT-P) subscales.

RESULTS

Only phenotypic and twin correlations in female twins met our threshold for twin modeling. The proportion of total variance for each trait accounted for by additive genetic factors ranged from 0.50 to 0.64 in female twins, with the rest explained by nonshared environmental factors and measurement error. Shared environmental factors played a minimal role in the variance of each trait. The strongest genetic correlation (ra ) emerged between EDI bulimia and AUDIT-P (ra  = 0.46, 95% confidence interval: 0.37, 0.55), indicating that the proportion of genetic variance of one trait that was shared with the other trait was 0.21. Nonshared environmental correlations between eating disorder dimensions and alcohol involvement ranged from 0.03 to 0.13.

CONCLUSIONS

We observed distinct patterns of genetic and environmental effects for co-occurring eating disorder dimensions and alcohol involvement in female vs. male twins, supporting sex-specific treatment strategies for late adolescents with comorbid eating disorders and alcohol use disorder. Our findings emphasize the importance of assessing family history of multiple eating disorder dimensions while treating late adolescents with problematic alcohol use, and vice versa, to improve detection and treatment.

A Gateway That Never Was

This brief communication responds to the article by Rajabi et al., recently published in Behavior Genetics. To test the hypothesis of cigarette smoking as a "gateway" for subsequent opium use and contrast it with the common liability model, Mendelian randomization analysis was applied to data obtained from an Iranian sample, using CHRNA3 rs1051730 as an instrumental variable. It is doubtful, however, if the assumptions of instrumental variable analysis hold in this case. The authors misstate both the gateway hypothesis and the common liability model. The article has many other deficiencies that diminish the veracity of its categorical conclusions that accept the causal interpretation of the "gateway hypothesis" and reject the common liability model, with which the data are fully consistent.

Binge eating and alcohol consumption: an integrative review

OBJECTIVE

To identify the relationship between binge eating and alcohol consumption.

METHODS

This is an integrative literature review of publications from 2015 to 2019, using the Pubmed, Cinhahl, Psynet, Lilacs, Embase and Web of Science virtual databases and the descriptors ("Binge-Eating" OR "Bulimia") AND Alcohol* in English, Spanish and Portuguese.

RESULTS

A total of 964 articles were found. After reading the titles and abstracts and excluding duplicates, 36 articles were included in the final sample (35 in English and one in Portuguese). They were grouped into three thematic categories: "sample profile and characterization", "genetic and environmental factors", and "emotions and behavior".

CONCLUSIONS

The data indicate the existence of a relationship between binge eating and alcohol use, and some factors were associated with this comorbidity. Still, there were few publications on the theme at the national level, indicating the need for developing more research. These findings may support therapeutic actions and strategies for identification of cases, embracing approaches and more effective treatments to meet the individual's biopsychosocial demands.

LEVEL OF EVIDENCE

Level V, narrative review.

Impulsivity and anxiety-related dimensions in adults with bulimic-spectrum disorders differentially relate to eating disordered behaviors

While facets of both anxiety and impulsivity appear central to the development and maintenance of bulimia nervosa (BN), specific BN behaviors may be propagated by differing profiles of risk. The current study examined associations between dimensions of anxiety and impulsivity and BN symptoms (binge eating, vomiting, laxative misuse, driven exercise), both in terms of the presence of such behaviors and their frequency. Two hundred and four women (M_age = 25.7 years) who met DSM-IV criteria for full or subthreshold BN completed self-report measures of perfectionism (Frost Multidimensional Perfectionism Scale), anxiety (Spielberger Trait Anxiety Inventory), impulsivity (Barratt Impulsiveness Scale-11; Impulsive Behavior Scale), eating disordered behaviors (Eating Disorder Examination - Questionnaire), and associated psychiatric symptoms (Michigan Assessment Screening Test/Alcohol-Drug; Maudsley Obsessive-Compulsive Inventory). Factor analysis revealed multidimensional impulsive and anxiety-related traits (5 anxiety-related factors; 7 impulsivity-related factors). In zero-sensitive regression models, different facets of impulsivity evidenced association with the presence of binge eating (risk taking), laxative misuse (impulsive spending), and fasting (difficulty concentrating), along with the frequency of vomiting (long-term planning difficulties). In contrast, anxiety-related dimensions were only associated with driven exercise (high standards) and fasting (concern over mistakes, high standards, parental expectations). Overall, impulsive and anxiety-related factors and symptoms showed distinct associations with specific eating disorder behaviors, even among those with the same diagnosis.

Genetics of Eating Disorders: What the Clinician Needs to Know

Anorexia nervosa (AN), bulimia nervosa (BN), and binge-eating disorder (BED) are heritable conditions that are influenced by both genetic and environmental factors. Recent genome-wide association studies (GWAS) of AN have identified specific genetic loci implicated in AN, and genetic correlations have implicated both psychiatric and metabolic factors in its origin. No GWAS have been performed for BN or BED. Genetic counseling is an important tool and can aid families and patients in understanding risk for these illnesses.

Illicit Drug Use, Cigarette Smoking, and Eating Disorder Symptoms: Associations in an Adolescent Twin Sample

OBJECTIVE

Twin studies have shown that genetic factors in part explain the established relation between alcohol use (i.e., problematic use or abuse/dependence) and eating disorder symptoms in adolescent and adult females. However, studies have yet to elucidate if there are similar shared genetic factors between other aspects of substance involvement, such as illicit drug use and repeated cigarette smoking.

METHOD

For those sex-specific phenotypic correlations above our threshold of .20, we used a behavioral genetic design to examine potential shared genetic overlap between self-reported lifetime illicit drug use and repeated cigarette smoking and the eating disorder symptoms of drive for thinness (DT), bulimia (BU), and body dissatisfaction (BD), as assessed with the Eating Disorder Inventory-II, in 16- to 17-year-old female and male twin pairs.

RESULTS

Only phenotypic correlations with illicit drug use met our threshold for twin modeling. Small to moderate genetic correlations were observed between illicit drug use and BU in both girls and boys and between illicit drug use and DT in girls.

CONCLUSIONS

Similar etiological factors are at play in the overlap between illicit drug use and certain eating disorder symptoms in girls and boys during adolescence, such that genetic factors are important for covariance. Specifically, illicit drug use was associated with bulimia nervosa symptoms in girls and boys, which parallels previous substance use research finding a genetic overlap between alcohol use and bulimia nervosa symptoms. Future research should prospectively examine developmental trajectories to further understand the etiological overlap between substance involvement and eating disorder symptoms.

Associations Between Alcohol Involvement and Drive for Thinness and Body Dissatisfaction in Adolescent Twins: A Bivariate Twin Study

BACKGROUND

Alcohol involvement has familial associations with bulimic symptoms (i.e., binge eating, inappropriate compensatory behaviors), with several studies indicating a genetic overlap between the two. It is unclear whether overlapping familial risk with alcohol involvement extends to other eating disorder symptoms. Understanding the genetic overlap between alcohol involvement and other eating disorder symptoms may aid in more targeted interventions for comorbid alcohol use-eating disorder symptoms. Thus, we investigated associations between alcohol involvement and 2 core eating disorder symptoms: drive for thinness and body dissatisfaction in adolescent female and male twins.

METHODS

We assessed 3 levels of alcohol involvement: alcohol use in the last month, having ever been intoxicated, and alcohol intoxication frequency via self-report. The Eating Disorder Inventory-II assessed drive for thinness and body dissatisfaction. Sex-specific biometrical twin modeling examined the genetic overlap between alcohol involvement and eating disorder symptoms.

RESULTS

Phenotypic associations between alcohol involvement, drive for thinness, and body dissatisfaction were significantly greater in girls compared with boys. A majority of the associations between alcohol involvement, drive for thinness, and body dissatisfaction in girls, but not boys, met our threshold for twin modeling (phenotypic r > 0.20). Moderate genetic correlations were observed between the 3 aspects of alcohol involvement and drive for thinness. Moderate genetic correlations were observed between alcohol use and intoxication frequency and body dissatisfaction.

CONCLUSIONS

Together with the literature on alcohol involvement and bulimic symptoms, these findings suggest a generalized association between alcohol involvement and eating disorder symptoms in girls, whereas this association may be symptom specific in boys. Genetic correlations indicate that the amount and direction of this genetic overlap differs across specific symptoms. When intervening on comorbid alcohol involvement and eating disorder symptoms, it may be important to target-specific eating disorder symptoms.

Shared familial risk between bulimic symptoms and alcohol involvement during adolescence

Twin studies show the established relation between bulimic symptoms and problematic alcohol involvement in adult females is partly due to shared familial factors, specifically shared genetic effects. However, it is unclear if similar shared etiological factors exist during adolescence or in males. We examined the familial overlap (i.e., genetic and common environmental correlations) between bulimic symptoms and various levels of alcohol involvement in 16- to 17-year-old female and male same-sex twin pairs using sex-specific biometrical twin modeling. Bulimic symptoms were assessed with the Eating Disorder Inventory-2. Alcohol involvement included alcohol use in the last month, having ever been intoxicated, and alcohol intoxication frequency. Results revealed 3 distinct patterns. First, in general, phenotypic correlations indicated statistically similar associations between bulimic symptoms and alcohol involvement in girls and boys. Second, common environmental overlap was significant for the bivariate associations including having ever been intoxicated. Third, moderate genetic correlations were observed between all bulimic symptoms and alcohol involvement in girls and moderate common environmental correlations were observed in boys for the more risky/deviant levels of involvement. Similar to adults, there is familial overlap between bulimic symptoms and alcohol involvement in adolescent girls and boys. These results could inform symptom- and sex-specific, developmentally targeted prevention and intervention programs for the comorbidity between bulimic symptoms and alcohol involvement. (PsycINFO Database Record

Genetic epidemiology of eating disorders

PURPOSE OF REVIEW

We capture recent findings in the field of genetic epidemiology of eating disorders. As analytic techniques evolve for twin, population, and molecular genetic studies, new findings emerge at an accelerated pace. We present the current status of knowledge regarding the role of genetic and environmental factors that influence risk for eating disorders.

RECENT FINDINGS

We focus on novel findings from twin studies, population studies using genetically informative designs, and molecular genetic studies. Over the past 2 years, research in this area has yielded insights into: comorbidity with other psychiatric and medical disorders and with metabolic traits; developmental factors associated with the emergence of eating disorders; and the molecular genetics of anorexia nervosa.

SUMMARY

Insights from genetic epidemiology provide an important explanatory model for patients with eating disorders, family members, and clinicians. Understanding core biological determinants that explain the severity and persistence of the illnesses, their frequent co-occurrence with other conditions, and their familial patterns raises awareness and increases compassion for individuals living with these disorders. Large-scale genomic studies are currently underway. Ultimately, this domain of research may pave the way to greater understanding of the underlying neurobiology and inform the development of novel and effective interventions.

Risky drinking behaviors among women with eating disorders-A longitudinal community-based study

OBJECTIVE

Eating disorders and alcohol use disorders often co-occur, but few prospective studies have examined their relationship. Using a large population-based twin sample, we investigated how the drinking behaviors of women with lifetime eating disorders unfold from adolescence to adulthood.

METHOD

We identified 182 women with a lifetime eating disorder assessed at mean age 24, including 92 women with DSM-5 anorexia nervosa and 58 women with DSM-5 bulimia nervosa, from the 1975-1979 birth cohorts of Finnish twins (N = 2,825 women). Frequency of drinking and intoxicating were assessed at ages 16, 24, and 34. Drinking problems were assessed at ages 24 and 34 by the Malmö-modified Michigan Alcohol Screening Test (Mm-Mast) and the Rutgers Alcohol Problem Index (RAPI).

RESULTS

At age 16, proportionately more women with eating disorders reported being severely intoxicated when they last drank (25% vs.16%, P = 0.001), and at both surveys in adulthood, they reported more frequent intoxication and more alcohol-related problems than their unaffected peers. Those who had recovered from their eating disorder at age 24 still reported more alcohol-related problems in their 30s than did other women. The age of drinking onset, number of monthly drinking days, or frequency of intoxication in adolescence did not differ between women with lifetime eating disorders and unaffected women.

DISCUSSION

Women with eating disorders scored higher than their unaffected peers on scales measuring alcohol dependence, alcohol-related problems, and intoxication. These differences persisted from mid-adolescence into young adulthood. Women with eating disorders should be assessed routinely for drinking behaviors. © 2016 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:563-571).

Genetic and environmental components to self-induced vomiting

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.

A Primer on the Genetics of Comorbid Eating Disorders and Substance Use Disorders

Eating disorders (EDs) and substance use disorders (SUDs) frequently co-occur; however, the reasons for this are unclear. We review the current literature on genetic risk for EDs and SUDs, as well as preliminary findings exploring whether these classes of disorders have overlapping genetic risk. Overall, genetic factors contribute to individual differences in liability to multiple EDs and SUDs. Although initial family studies concluded that no shared familial (which includes genetic) risk between EDs and SUDs exists, twin studies suggest a moderate proportion of shared variance is attributable to overlapping genetic factors, particularly for those EDs characterized by binge eating and/or inappropriate compensatory behaviours. No adoption or molecular genetic studies have examined shared genetic risk between these classes of disorders. Research investigating binge eating and inappropriate compensatory behaviours using emerging statistical genetic methods, as well as examining gene-environment interplay, will provide important clues into the aetiology of comorbid EDs and SUDs.