*Limitations*

In this study, not all the potential confounding effects in the analysis were considered. Relevant variables include the age of onset and duration of EDs, specific type of ED, information on treatment, dietary intake, suicidal ideation/attempts, and potential

comorbidities. Prior studies on ED patients suggested that these factors predicted the time to death [4,63]. According to Statistics Canada regulations, the number of these variables in the current study was insufficient to release the data (such as suicidal ideation/attempts) or were not measured in the data source. However, the current study was not designed to make a causal statement of the effects of EDs, independent of other variables, on mortality, but rather to describe the pattern of mortality in this population.

Another limitation is the lack of information regarding if the EDs cases also include binge eating disorder and other specified feeding or eating disorders, since in this study, the screening of current and lifetime EDs was based on a dichotomous question "Do you have an eating disorder such as anorexia or bulimia?". While the self-reported current and lifetime-screening questions have a reliable specificity and sensitivity, bulimia nervosa compared to other ED types has poorer reliability in identifying true cases [23], which might be one of the reasons that the prevalence of EDs in our population is lower than other reports based on psychometric questionnaires. However, another possible reason for this prevalence discrepancy might be because they represent more severe groups, i.e., those who have sought professional help [23].

CCHS in Canada represents over 97% of the Canadian population aged ≥15, which covers the ten provinces and the three territories, while excluding those persons who meet the exclusion criteria [25,26]. Therefore, these findings cannot be generalized to these groups. Furthermore, in Canada, health care is based on a universal healthcare system, meaning that it is largely based on need rather than the ability to pay, permitting Canadians to have access to most healthcare services [64]. A universal healthcare system reduces, though does not eliminate, the potential inequalities in accessing care for the initial diagnosis of EDs by a healthcare provider among people with different socioeconomic backgrounds [64,65].

#### **5. Conclusions**

To our knowledge, the current study, for the first time, has reported the all-cause mortality of self-reported lifetime history of EDs in a population-based study. This finding highlights the seriousness of these disorders and supports the idea that there is an urgent need for strategies that may help to improve long-term outcomes, such as a need for public education for early diagnosis and a long-term plan for adequate early intervention. Different types of research would be needed to understand the underlying causal mechanism and, consequently, formulate a preventive strategy.

**Author Contributions:** P.P. is the first author: analyzing the data and interpreting the results and leading in the preparation of the manuscript; S.B.P.: conceiving the original idea, contributing to the design and implementation of the research, supervising the project, interpreting the results, and providing critical feedback; A.G.M.B.: contributing to interpreting the results and providing critical feedback to the final manuscript; J.V.A.W.: analyzing the data, contributing to interpreting the results, and providing critical feedback; G.D. is the senior author and an expert in eating disorders: contributing to the design and implementation of the research, interpreting the results, and revising the manuscript. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by the Cuthbertson and Fischer Chair in Pediatric Mental Health, held by Scott Patten at the University of Calgary.

**Institutional Review Board Statement:** Ethical review and approval were waived for this study, due to the Canadian Interagency Advisory Panel on Research Ethics, Tri-Council Policy Statement 2 (2018), chapter 5, Article 5.5A. Information is available at: https://ethics.gc.ca/eng/tcps2-eptc2\_201 8\_chapter5-chapitre5.html#5a (access on 21 September 2021).

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.

**Data Availability Statement:** The data used in this analysis are available through the Research Data Centers Program. Information is available at: http://www.statcan.gc.ca/eng/rdc/index (accessed on 21 September 2021).

**Acknowledgments:** This study was supported by a pilot grant from the Mathison Centre for Mental Health Research & Education. The analysis was conducted at the Prairie Regional Data Centre, which is part of the Canadian Research Data Centre Network (CRDCN). The services and activities provided by the CRDCN are made possible by the financial or in-kind support of the SSHRC, the CIHR, the CFI, Statistics Canada, and participating universities, whose support is gratefully acknowledged. The views expressed in this paper do not necessarily represent the CRDCN's or those of its partners.

**Conflicts of Interest:** The authors have no conflict of interest to declare.

### **References**

