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 pro spectively 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 de fined by all liveborn girls in Sweden from 1973 to 1984. From the Swedish I npatient Register, 781 girls had been discharged from any hospital in Swede n with a main diagnosis of anorexia nervosa at the age of 10 to 21 years. F or each case, 5 controls were randomly selected, individually matched by ye ar and hospital of birth (n = 3905). Conditional logistic regression was us ed to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for po tential risk factors. Results: Increased risk of anorexia nervosa was found for girls with a ceph alhematoma (OR, 2.4; 95% CI, 1.4-4.1) and for very preterm birth (less than or equal to 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 fo r gestational age (OR, 2.7; 95% CI, 1.2-5.8). Conclusions: Our results show that perinatal factors, possibly reflecting b rain damage, had independent associations with anorexia nervosa. These risk factors may uncover the mechanisms underlying the development of the disor der, even if only a fraction of cases of anorexia nervosa may be attributab le to perinatal factors.