The incidence of eating disorders in a Danish register study: Associations with suicide risk and mortality

https://doi.org/10.1016/j.jpsychires.2015.03.003Get rights and content

Highlights

  • •

    Adolescence represents a high-risk period for the onset of eating disorders.

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    For AN, the peak age of risk was earlier for males than females (13 vs. 15 years).

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    Broadening AN criteria leads to increased rates of incidence for AN in females.

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    Broadening AN criteria does not attenuate morbidity and mortality.

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    Eating disorders significantly increase the hazard for suicide attempts and deaths.

Abstract

Our aim was to characterize the incidence rates and cumulative incidence of anorexia nervosa (AN), bulimia nervosa (BN), and eating disorder not otherwise specified (EDNOS), and examine associations among eating disorder diagnoses, suicide attempts, and mortality. Individuals born in Denmark between 1989 and 2006 were included (N = 966,141, 51.3% male). Eating disorders diagnoses (AN, broad AN, BN, EDNOS) were drawn from the Danish Psychiatric Central Research Register (PCRR) and Danish National Patient Register (NPR). Suicide attempts and deaths were captured in the NPR, the PCRR, and the Danish Civil Registration System (CRS). In females, AN had a peak hazard at approximately age 15 years, BN at 22 years, and EDNOS had an extended peak that spanned 18 years–22 years. Eating disorder diagnoses predicted a significantly higher hazard for death and suicide attempt compared with the referent of individuals with no eating disorders. In males, peak hazard for diagnosis was earlier than in females. The present study represents one of the largest and longest studies of eating disorder incidence and suicide attempts and death in both females and males. Eating disorders are accompanied by increased hazard of suicide attempts and death even in young adults.

Section snippets

Aims of the study

The overarching aim of the present study was to characterize the incidence rates and cumulative incidence of AN, BN, and EDNOS as detected in outpatient and inpatient care for individuals born in Denmark between 1989 and 2006 (∼1 million individuals). We investigated patterns of peak age of risk for eating disorders across sex and associations among eating disorder status, mortality, and suicide attempts across diagnoses.

The registers

In 1968, the Danish Civil Registration System (CRS) was established. Since that time, every person living in Denmark or alive at the time the CRS was established has been assigned a CRS number (Pedersen et al., 2006). The CRS number serves as a unique personal identifier and enables linkage across all national registers. The CRS includes each individual's CRS number, parental CRS numbers, sex, date of birth, and vital status, and is continuously updated.

The Danish National Patient Register

Eating disorders incidence

The age- and sex-specific incidence rates were calculated as the number of new cases occurring at each age category/group in females and males separately and reported per 10,000 person years. Person-years—the sum of years that individuals in the study population have been followed—is commonly used as a denominator in epidemiological studies of incidence rates in order to account for situations in which the amount of observation time differs between individuals (Vandenbroucke and Pearce, 2012).

Incidence rate

The incidence rate per 10,000 person-years by age, sex and type of eating disorder is presented in Table 1.

Discussion

With a total sample of 966,141 and a follow-up period of 15 years, the present study represents one of the largest and longest studies of eating disorder incidence and mortality in adolescence and young adulthood.

Role of the funding source

This research was supported by the Anorexia Nervosa Genetics Initiative (ANGI), an initiative of the Klarman Family Foundation. The authors had sole responsibility for the study design, data analysis, data interpretation, writing of the report, and decision to submit the article for publication. Data were collected by the Danish Psychiatric Central Research Register (PCRR) and Danish National Patient Register (NPR).

Contributors

SZ, JL, LP, LT, PM, and CB were involved in the concept and design of the study and contributed to the statistical analysis plan. JL and LP were responsible for extraction of the data from the Danish registers. JL, LP and PM were responsible for data analysis. SZ, LT and CB drafted the manuscript and all authors were involved in interpretation of the data, critical revision, and approval of the final content before submission.

Conflict of interests

Dr. Bulik is a consultant for Shire Pharmaceuticals.

Acknowledgments

Dr. Zerwas is supported by a NIMH training grant (K01MH100435). This research was supported by the Anorexia Nervosa Genetics Initiative (ANGI), an initiative of the Klarman Family Foundation.

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