Associations Between Birth Characteristics and Eating Disorders Across the Life Course: Findings From 2 Million Males and Females Born in Sweden, 1975–1998

Abstract

Birth characteristics predict a range of major physical and mental disorders, but findings regarding eating disorders are inconsistent and inconclusive. This total-population Swedish cohort study identified 2,015,862 individuals born in 1975-1998 and followed them for anorexia nervosa, bulimia nervosa, and eating disorder not otherwise specified until the end of 2010. We examined associations with multiple family and birth characteristics and conducted within-family analyses to test for maternal-level confounding. In total, 1,019 males and 15,395 females received an eating disorder diagnosis. Anorexia nervosa was independently predicted by multiple birth (adjusted hazard ratio = 1.33, 95% confidence interval: 1.15, 1.53) for twins or triplets vs. singletons) and lower gestational age (adjusted hazard ratio = 0.96, 95% confidence interval: 0.95, 0.98) per extra week of gestation, with a clear dose-response pattern. Within-family analyses provided no evidence of residual maternal-level confounding. Higher birth weight for gestational age showed a strong, positive dose-response association with bulimia nervosa (adjusted hazard ratio = 1.15, 95% confidence interval: 1.09, 1.22, per each standard-deviation increase), again with no evidence of residual maternal-level confounding. We conclude that some perinatal characteristics may play causal, disease-specific roles in the development of eating disorders, including via perinatal variation within the normal range. Further research into the underlying mechanisms is warranted. Finally, several large population-based studies of anorexia nervosa have been conducted in twins; it is possible that these studies considerably overestimate prevalence.

Obstetric complications and eating disorders: A replication study

“…Retarded fetal growth may be associated with metabolic changes and alterations in the programming of appetite and stress‐response systems which, in interaction with genetic vulnerability, may increase the risk of developing bulimic symptoms. Although this finding was replicated in our two studies, it needs replication in larger samples, since our data are in contradiction with those of a recent large case‐register study that found, on the contrary, an association between high birth weight and BN.…”

“…Taken together, despite inconsistencies and the methodological biases that limit both the compatibility and comparison of data from differing sources, OCs are considered to be putative risk factors for the development of AN and BN. It is noteworthy that only few studies to date have addressed this question in BN . It is important to build large homogeneous datasets to explore the role of OCs in the development of these disorders and to examine their interactions with other risk factors, including specific genetic polymorphisms.…”

Family History of Education Predicts Eating Disorders across Multiple Generations among 2 Million Swedish Males and Females

“…On the contrary, a larger absolute number of cases occurred among daughters of less educated parents (Table 1), because they represent a larger share of the population. Nevertheless, the higher rate of female ED in high SEP families supports three previous large studies [5]–[7] and extends these by suggesting that the same is true for anorexia nervosa in males (see also [28]). …”

Eating Disorders and Breast Cancer

“…(1) These estimates are consistent with the estimated lifetime prevalence of eating disorders in our study sample, which was approximately 3%. Any slight increase in prevalence for our sample is expected, given that eating disorders may be more common in women from more highly educated families (3, 33) and that incidence has been increasing over time (1, 34). …”