Very preterm birth, birth trauma, and the risk of anorexia nervosa among girls.
BACKGROUND
Obstetrical complications, based on parental recall, have been reported to be associated with development of anorexia nervosa. We used prospectively collected data about pregnancy and perinatal factors to examine the subsequent development of anorexia nervosa.


METHODS
This population-based, case-control study was nested in cohorts defined by all liveborn girls in Sweden from 1973 to 1984. From the Swedish Inpatient Register, 781 girls had been discharged from any hospital in Sweden with a main diagnosis of anorexia nervosa at the age of 10 to 21 years. For each case, 5 controls were randomly selected, individually matched by year and hospital of birth (n = 3905). Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for potential risk factors.


RESULTS
Increased risk of anorexia nervosa was found for girls with a cephalhematoma (OR, 2.4; 95% CI, 1.4-4.1) and for very preterm birth (< or = 32 completed gestational weeks) (OR, 3.2; 95% CI, 1.6-6.2). In very preterm births, girls who were small for gestational age faced higher risks (OR, 5.7; 95% CI, 1.1-28.7) than girls with higher birth weight for gestational age (OR, 2.7; 95% CI, 1.2-5.8).


CONCLUSIONS
Our results show that perinatal factors, possibly reflecting brain damage, had independent associations with anorexia nervosa. These risk factors may uncover the mechanisms underlying the development of the disorder, even if only a fraction of cases of anorexia nervosa may be attributable to perinatal factors.
Cnattingius
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Department of Medical Epidemiology, Karolinska Institute, Stockholm, Sweden. Sven.Cnattingius@mep.ki.se
Hultman
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CM
Dahl
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Sparén
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D000293:Adolescent; D000328:Adult; D000856:Anorexia Nervosa / Q000453:epidemiology*; D001034:Apgar Score; D001720:Birth Injuries / Q000453:epidemiology*; D001724:Birth Weight; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007236:Infant, Small for Gestational Age; D008423:Maternal Age; D007752:Obstetric Labor, Premature; D011247:Pregnancy; D012307:Risk Factors; D012737:Sex Factors