A nation-wide study of the family aggregation and risk factors in anorexia nervosa over three generations.
OBJECTIVE
This nation-wide register-based study investigated how often anorexia nervosa (AN) and co-morbid disorders occur in affected families compared with control families. Furthermore, the study addressed the impact of sex, year of birth, and degree of urbanization in terms of risk factors.


METHODS
A total of N = 2,370 child and adolescent psychiatric subjects born between 1951 and 1996 and registered in the Danish Psychiatric Central Research Register (DPCRR) had any mental disorder before the age of 18 and developed AN at some point during their life-time. In addition, N = 7,035 controls without any psychiatric diagnosis before age 18 and matched for age, sex, and residential region were included. Psychiatric diagnoses were also obtained on the first-degree relatives as a part of the Danish Three Generation Study (3GS). A family load component was obtained by using various mixed regression models.


RESULTS
AN occurred significantly more often in case than in control families. AN Risk factors included having a sibling with AN, affective disorders in family members, and co-morbid affective, anxiety, obsessive-compulsive, personality, or substance use disorders. Furthermore, female sex, and ascending year of birth were significantly associated with having AN. Urbanization was not related to the family load of AN and case-relatives did not develop AN earlier than control relatives.


CONCLUSIONS
These findings based on a very large and representative dataset provide evidence for the family aggregation and further risk factors in AN.
Research Unit for Child and Adolescent Psychiatry, Psychiatric Hospital, Aalborg University Hospital, Aalborg, Denmark; Clinical Psychology and Epidemiology, Institute of Psychology, University of Basel, Switzerland; Department of Child and Adolescent Psychiatry, University of Zurich, Switzerland.
Hans-Christoph
HC
Steinhausen
Helle
H
Jakobsen
Dorte
D
Helenius
Povl
P
Munk-Jørgensen
Michael
M
Strober
D000293:Adolescent; D000328:Adult; D000856:Anorexia Nervosa / Q000453:epidemiology* / Q000209:etiology*; D001008:Anxiety Disorders / Q000453:epidemiology; D016022:Case-Control Studies; D015897:Comorbidity; D003718:Denmark / Q000453:epidemiology; D005190:Family / Q000523:psychology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D001523:Mental Disorders / Q000150:complications* / Q000453:epidemiology; D008875:Middle Aged; D010554:Personality Disorders / Q000453:epidemiology; D012042:Registries; D012307:Risk Factors; D035781:Siblings; D019966:Substance-Related Disorders / Q000453:epidemiology; D014507:Urbanization
anorexia nervosa; early onset; family based register study