title: Age at onset of anorexia nervosa and breast cancer risk.
abstract: The objective of this study was to investigate breast cancer occurrence among women treated for anorexia nervosa (AN), with emphasis on age at the onset of this disorder. We conducted a register-based retrospective cohort with a total of 6009 women with at least one admission with an AN diagnosis during the period 1973-2003 in Sweden. During a mean follow-up of 13.4 years, information on 80 057 women-years was generated. The standardized incidence ratio (SIR)--the ratio of observed-to-expected number of cases--was used as the measure of relative risk. Overall, 16 women developed breast cancer versus 25.5 expected cases [SIR: 0.6, 95% confidence interval (CI): 0.4-0.9]. Among women who were first admitted for AN between the age of 10 and 24 years, four developed breast cancer versus 11.3 expected (SIR: 0.4, 95% CI: 0.1-0.9). In this group of women with early onset AN, only one parous woman developed breast cancer versus 6.3 expected (SIR: 0.2, 95% CI: 0-0.9). Among women first hospitalized for AN between the age of 25 and 40 years, 12 developed breast cancer, whereas the expected number was 14.2, a nonsignificant deficit. Our results suggest that early onset AN may play an important role in the development of breast cancer, possibly because of the extreme restriction of energy intake at a crucial period for mammary gland development. Late onset AN is likely to play a relatively less important role.
authors.affiliation: Department of Neuroscience, Psychiatry, Uppsala University Hospital, Uppsala, Sweden. fotis.papadopoulos@gmail.com
authors.forename: Fotios C
authors.initials: FC
authors.lastname: Papadopoulos
authors.forename: Ioannis
authors.initials: I
authors.lastname: Pantziaras
authors.forename: Pagona
authors.initials: P
authors.lastname: Lagiou
authors.forename: Lena
authors.initials: L
authors.lastname: Brandt
authors.forename: Lisa
authors.initials: L
authors.lastname: Ekselius
authors.forename: Anders
authors.initials: A
authors.lastname: Ekbom
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D000856:Anorexia Nervosa / Q000150:complications*; D001943:Breast Neoplasms / Q000150:complications* / Q000453:epidemiology; D031204:Caloric Restriction; D002648:Child; D015331:Cohort Studies; D002149:Energy Intake / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult