Sex‐ and age‐specific incidence of healthcare‐register‐recorded eating disorders in the complete swedish 1979–2001 birth cohort

Abstract

Objective To investigate the sex- and age-specific incidence of healthcare-register-recorded anorexia nervosa (AN) and other eating disorders (OED) in a complete birth cohort, and assess whether incidence varies by diagnostic period and (sub-) birth cohort. Method We used the actuarial method and Poisson models to examine the incidence of AN and OED from 1987–2009 (when individuals were 8–30 years) for a cohort of 2.3 million individuals (48.7% female) born from 1979–2001 in Sweden, identified using Swedish registers. Results For both sexes, incidences of AN and OED increased considerably for diagnostic periods after 2000, but differed little by birth cohort. In 2009, AN incidence in the peak age category was 205.9 cases/100,000 persons (95% CI: 178.2, 233.5) for females (14–15 years), versus 12.8 cases/100,000 (95% CI: 5.6, 20.1) for males (12–13 years). OED incidence in the peak age category was 372.1 cases/100,000 (95% CI: 336.4, 407.9) for females (16–17 years), versus 22.2 cases/100,000 (95% CI: 13.3, 31.1) for males (14–15 years). Discussion Our finding of an increase in healthcare register-recorded eating disorders for diagnostic periods after 2000 likely reflects improved detection and expanded register coverage in Sweden. The peak of eating disorder incidence in adolescence, which began unexpectedly early for AN in males, suggests the importance of vigilance for signs of AN in young boys and early primary prevention efforts. Waiting until later could miss critical windows for intervention that could prevent disorders from taking root.

Familial Liability for Eating Disorders and Suicide Attempts

“…First, the lifetime prevalence of eating disorders that we observed in the register data was lower than the survey-based lifetime prevalence in other studies, 1 including one based on Swedish adult twins. 31 This difference could be the result of (1) register data capturing only treatmentseeking cases (and treatment seeking can differ across eating disorders), (2) the coverage of the eating disorder quality registers increasing over time, 22 and (3) for BN particularly, the diagnosis being unavailable in the Swedish version of the ICD-9.…”

Paternal age at childbirth and eating disorders in offspring

“…However, the registers detect eating disorder diagnoses made in multiple contexts (e.g., in the emergency room), not only in the context of eating disorder or psychiatric treatment. Further, given the relatively low incidence of eating disorders in Sweden (Javaras et al 2015), it is likely that only a small proportion of the cohort had an eating disorder that was not detected or recorded. Second, we could not examine the association between paternal age and incidence of specific eating disorders other than AN (e.g., BN) because ICD-9 in Sweden included them under a single diagnostic code.…”

“…2010), which first entered patient information in 1999 and 2005, respectively, and currently include information from almost all specialized eating disorder units in Sweden (≈90% as of 2009) and many non-specialized general psychiatric units; (4) the Multi-Generation Register, which can be used to determine biological and adoptive relationships for all individuals living in Sweden since 1932; (5) the Migration Register, which records information on emigration from or immigration to Sweden since 1901; (6) the Cause of Death Register, which contains the date and principal and contributing cause(s) of deaths occurring since 1952; (7) the National Crime Register, which includes detailed information about all criminal convictions since 1973; and (8) the Education Register, which contains information on highest level of completed formal education through 2008. Additional information about the registers and variables derived from them are provided elsewhere (D’Onofrio et al 2013a; Javaras et al. 2015).…”

“…All models were adjusted for participant sex. In addition, all models were adjusted for calendar year (treated as a continuous, time-varying covariate, and measured in units of years rounded to the nearest digit), because prior research reveals that incidence rates for AN and AED increase dramatically after 2000 due to expanded coverage of the healthcare registers to psychiatric outpatient settings (Javaras et al 2015). To examine the effects of adjusting for potential confounders (of the relationship between paternal age and offspring eating disorders), we fit a series of models with the following additional covariates: Model A (the ‘baseline model’) included only participant sex and calendar year; Model B included all Model A covariates and participant birth order; Model C included all Model B covariates and maternal age; and Model D (the ‘fully-adjusted model’) included all Model C covariates and several fixed maternal and paternal covariates [country of birth (Sweden or other country); highest level of education attained; lifetime history of severe psychiatric disorders (i.e., ICD diagnoses for schizophrenia or bipolar disorder); and lifetime criminality (i.e., conviction for any crime at 15 years or older)].…”

Toward a new generation of quality registries for neurodevelopmental disorders: the example of NEUROPSYK

“…QRs in Sweden serve as important tools for the evaluation and improvement of health care services, and they provide a primary data source for epidemiological and longitudinal research (8)(9)(10). QRs contain individualized information about patients' diagnoses, diagnostic assessments, medical interventions, treatment outcomes, and patientreported outcome measures.…”