Parent-child age gaps in patients with anorexia and bulimia nervosa and their associations with family dysfunction.

Background: Family factors are linked to the development of anorexia nervosa (AN) and bulimia nervosa (BN). However, due to a lack of direct comparison, it is still unknown whether the two entities of eating disorders differ with respect to the age gaps between parents and their affected children.

Methods: In a cohort of 568 patients from the FamFINED study (FAMily Factors INvolved in Eating Disorders) diagnosed with eating disorders, we assessed the relationships between the parent-child age differences and family dysfunction, as determined by means of the General Family Questionnaire ("Allgemeiner Familienbogen" [FBA]).

Results: Data showed that the age difference between the mother and the affected child was significantly higher in AN compared to BN patients (29.3 ± 5.3 vs. 28.3 ± 5.1 years, p = 0.017). Logistic regression confirmed that, also in adjusted models, the mother-child age difference significantly differed between the diagnoses of the two eating disorders (exp (B) = 0.918, 95% confidence interval 0.87-0.97, p = 0.004). However, the paternal age difference did not reach a statistical significance in the comparison between the two groups (p = 0.071).

Conclusions: The two entities of eating disorders differed significantly with respect to the age difference between the mother and the affected subject. The maternal age difference was higher in anorectic than in bulimic patients from the same study population. Further research is required to identify the psychophysiological mechanisms underlying these age-dependent effects.