Time trends in age at onset of anorexia nervosa and bulimia nervosa.
OBJECTIVE
This study aims to explore the time trends in age at onset of anorexia nervosa and bulimia nervosa.


METHODS
The sample was composed of 1,666 anorexia nervosa subjects and 793 bulimia nervosa subjects (according to DSM-IV criteria) without previous anorexia nervosa consecutively referred to our outpatient unit in the period between 1985 and 2008. Time trends in illness onset were analyzed according to the year of birth of subjects.


RESULTS
In both anorexia nervosa and bulimia nervosa, age at onset showed a significant decrease according to year of birth. A regression model showed a significant independent effect of socioeconomic status, age at menarche, and number of siblings in predicting age at onset lower than 16 years.


CONCLUSIONS
Age at onset of anorexia nervosa and bulimia nervosa is decreasing in younger generations. The implications of our findings in terms of long-term outcome remain to be understood. Biologic and sociocultural factors explaining this phenomenon need to be explored in future studies.
Department of Neuroscience, University of Padova, Italy.
Angela
A
Favaro
Lorenza
L
Caregaro
Elena
E
Tenconi
Romina
R
Bosello
Paolo
P
Santonastaso
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000553:Ambulatory Care; D000856:Anorexia Nervosa / Q000175:diagnosis* / Q000453:epidemiology; D052018:Bulimia Nervosa / Q000175:diagnosis* / Q000453:epidemiology; D002648:Child; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D005865:Gestational Age; D006801:Humans; D008297:Male; D008572:Menarche / Q000502:physiology; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010555:Personality Inventory; D011247:Pregnancy; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D012737:Sex Factors