Summary: A comprehensive study of adolescent twins reveals a genetic link between eating disorders and alcohol use disorders (AUD). This correlation underscores worse outcomes, including mortality, especially when these conditions manifest simultaneously in younger adolescents.
The study, conducted in the United States and Sweden, showed how these intertwined disorders are influenced differently in men and women. Research emphasizes the importance of sex-specific treatment strategies.
Key facts:
- The study highlighted a clear phenotypic correlation between eating disorders and alcohol consumption in various manifestations in women.
- Twin studies, a fundamental tool in this research, help discern between genetic and environmental influencers.
- Although non-shared environmental influences individually contribute to the disorders, they marginally influence their simultaneous occurrence, particularly in women.
Fountain: Alcoholism Research Society
Certain genetic influences contribute to eating disorders and problematic alcohol use, leaving some people vulnerable to both conditions, according to a large study of late adolescent twins.
Previous research has found that co-occurring eating disorders and risky drinking in younger adolescents amplify the chances of worse outcomes, including death. Studies across age groups have pointed to shared genetic influences for the two conditions, and other studies suggest that changes in one disorder may aggravate symptoms of the other.
Understanding genetic and environmental factors implicated in co-occurring eating disorders and alcohol use disorders (AUDs) could improve treatment and outcomes.
Adolescence is a key stage in life for onset, and the major transitions that characterize late adolescence may increase susceptibility. However, little is known about the various manifestations and combinations of eating disorders and AUDs in late adolescence or potential sex differences.
For the study published in Alcohol: clinical and experimental researchResearchers from the US and Sweden examined genetic and environmental risks across various dimensions and measures of eating and drinking disorders in 18-year-old twins.
Twin studies are a vital tool for differentiating between genetic and environmental influences. The researchers worked with 3,568 female and 2,526 male same-sex twins in Sweden.
Participants completed surveys assessing their thin drive, bulimia, body dissatisfaction, past-year alcohol use (frequency and quantity), and past-year alcohol problems (signs of dependence and harmful use).
The researchers looked for three types of influence: evidence of multiple genes working together to affect relevant traits; shared environmental factors, such as socioeconomic status, that make twins more similar on a given trait; and nonshared environmental factors (e.g., childhood trauma and peer influences), which cause twins to be more different on a given trait.
They used statistical analyzes to quantify genetic and environmental contributions to eating disorders associated with alcohol use.
Co-occurring eating and alcohol disorders manifested differently in male and female twins. In women, phenotypic correlation between conditions was evident in different manifestations of eating disorders and alcohol use. In men, the association was specific to problematic alcohol use.
In young women (but not men), drive for thinness, bulimia, and body dissatisfaction had mild to moderate genetic correlations with alcohol use and problems.
Overall, nonshared environmental influences contributed to separating eating disorder dimensions and alcohol measures, but contributed minimally to the coexistence of the two conditions in women. Some findings contrasted with previous research involving 16- and 17-year-old twins, possibly reflecting differences in alcohol consumption in relation to the legal drinking age in Sweden (18).
The study points to the importance of sex-specific treatment strategies for late adolescents with co-occurring eating disorders and problematic alcohol use. Additionally, the findings could help identify vulnerable adolescents.
Late adolescents who present with symptoms of eating disorders or problematic alcohol use could be screened for the other condition, which could improve detection and treatment. Assessing a family history of multiple manifestations of eating disorders also has value in screening and treatment.
The study did not identify specific genetic or environmental factors affecting co-occurring conditions. More research is needed on possible differences between countries and regions and more diverse populations.
About this research news in genetics and mental health.
Author: press office
Fountain: Alcoholism Research Society
Contact: Press Office – Alcoholism Research Society
Image: Image is credited to Neuroscience News.
Original research: Closed access.
“Differential genetic associations between eating disorder dimensions and alcohol involvement in late adolescent twins” by Baiyu Qi et al. Alcohol: clinical and experimental research
Abstract
Differential genetic associations between eating disorder dimensions and alcohol involvement in late adolescent twins.
Background
Twin studies have demonstrated shared genetic and environmental effects between eating disorders and alcohol involvement in middle-aged adults and adolescents. However, fewer studies have focused on late adolescents or investigated a broad range of eating disorder dimensions and alcohol involvement subscales in both sexes. We examined genetic and environmental correlations between three eating disorder dimensions and two alcohol involvement subscale scores in late adolescent twins using bivariate twin models.
Methods
Participants were 3,568 female and 2,526 male 18-year-old same-sex twins from the Swedish Child and Adolescent Twin Study. The Eating Disorders Inventory-2 (EDI) assessed thinness drive, bulimia, and body dissatisfaction. Alcohol involvement was assessed with the Alcohol Use Disorders Identification Test (AUDIT-C) and Problems (AUDIT-P) drinking subscales.
Results
Only phenotypic and twin correlations in twins met our threshold for twin modeling. The proportion of the total variance for each trait explained by additive genetic factors ranged from 0.50 to 0.64 in the twins, with the remainder explained by non-shared environmental factors and measurement errors. Shared environmental factors played a minimal role in the variation of each trait. The strongest genetic correlation (rto) arose between EDI bulimia and AUDIT-P (rto= 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. Non-shared 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 dimensions of eating disorders and alcohol involvement in female versus 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 dimensions of eating disorders while treating late adolescents with problematic alcohol use, and vice versa, to improve detection and treatment.
