Transgender Identity and Suicide Attempts and Mortality in Denmark

Key Points

Question  Do transgender individuals have higher rates of suicide attempt and mortality than nontransgender individuals?

Findings  In this nationwide cohort study of 6 657 456 Danish-born individuals, transgender individuals identified through hospital and administrative registers had significantly higher rates of suicide attempt (adjusted incidence rate ratio [aIRR], 7.7), suicide mortality (aIRR, 3.5), suicide-unrelated mortality (aIRR, 1.9), and all-cause mortality (aIRR, 2.0) compared with nontransgender individuals.

Meaning  This Danish population-based cohort study spanning more than 4 decades found that transgender individuals had higher rates of suicide attempt and mortality compared with nontransgender individuals.

Importance  Prior studies have suggested that transgender individuals may be a high-risk group with respect to suicide attempt and mortality, but large-scale, population-based investigations are lacking.

Objective  To examine in a national setting whether transgender individuals have higher rates of suicide attempt and mortality than nontransgender individuals.

Design, Setting, and Participants  Nationwide, register-based, retrospective cohort study on all 6 657 456 Danish-born individuals aged 15 years or older who lived in Denmark between January 1, 1980, and December 31, 2021.

Exposure  Transgender identity was determined through national hospital records and administrative records of legal change of gender.

Main Outcomes and Measures  Suicide attempts, suicide deaths, nonsuicidal deaths, and deaths by any cause during 1980 through 2021 were identified in national hospitalization and causes of death registers. Adjusted incidence rate ratios (aIRRs) with 95% CIs controlling for calendar period, sex assigned at birth, and age were calculated.

Results  The 6 657 456 study participants (50.0% assigned male sex at birth) were followed up during 171 023 873 person-years. Overall, 3759 individuals (0.06%; 52.5% assigned male sex at birth) were identified as transgender at a median age of 22 years (IQR, 18-31 years) and followed up during 21 404 person-years, during which 92 suicide attempts, 12 suicides, and 245 suicide-unrelated deaths occurred. Standardized suicide attempt rates per 100 000 person-years were 498 for transgender vs 71 for nontransgender individuals (aIRR, 7.7; 95% CI, 5.9-10.2). Standardized suicide mortality rates per 100 000 person-years were 75 for transgender vs 21 for nontransgender individuals (aIRR, 3.5; 95% CI, 2.0-6.3). Standardized suicide-unrelated mortality rates per 100 000 person-years were 2380 for transgender vs 1310 for nontransgender individuals (aIRR, 1.9; 95% CI, 1.6-2.2), and standardized all-cause mortality rates per 100 000 person-years were 2559 for transgender vs 1331 for nontransgender individuals (aIRR, 2.0; 95% CI, 1.7-2.4). Despite declining rates of suicide attempts and mortality during the 42 years covered, aIRRs remained significantly elevated in recent calendar periods up to and including 2021 for suicide attempts (aIRR, 6.6; 95% CI, 4.5-9.5), suicide mortality (aIRR, 2.8; 95% CI, 1.3-5.9), suicide-unrelated mortality (aIRR, 1.7; 95% CI, 1.5-2.1), and all-cause mortality (aIRR, 1.7; 95% CI, 1.4-2.1).

Conclusions and Relevance  In this Danish population-based, retrospective cohort study, results suggest that transgender individuals had significantly higher rates of suicide attempt, suicide mortality, suicide-unrelated mortality, and all-cause mortality compared with the nontransgender population.

The prevalence of transgender individuals, defined as persons whose gender identity or gender expression does not conform to that typically associated with the sex to which they were assigned at birth,¹ varies greatly between studies. A meta-analysis of 27 international studies conducted between 1968 and 2014 reported a prevalence of less than 0.01% based on transgender-related diagnoses.² In a US survey from 2014, the proportion of individuals aged 13 years or older identifying as transgender was estimated at 0.6%,³ and in a nationally representative study conducted in Denmark in 2017 to 2018, 0.1% of those aged 15 to 89 years were estimated to be transgender.⁴

The first gender identity–affirming surgery in Denmark took place in 1952.⁵ Since 1968, individuals undergoing such surgery could get their recorded sex updated in the national Civil Registration System to reflect their gender identity. In 2014, a law was passed enabling all Danish residents aged 18 years or older to apply for legal change of gender regardless of whether hormone therapy or gender identity–affirming surgery had taken place.⁶ In 2017, new guidelines were implemented to make transgender health care more accessible.⁷

Prior studies suggest a higher risk of suicide attempt and suicide among transgender individuals than that observed in the general population.^8-13 However, the existing evidence is largely derived from clinical samples or surveys in which sampling or information bias cannot be excluded.^8,9,11-13 The aim of the present national cohort study was to provide an updated, robust assessment of whether transgender individuals identified from hospital records and records of legal change of gender have higher rates of suicide attempt and of suicide, suicide-unrelated mortality, and all-cause mortality than the population of nontransgender individuals when data were adjusted for potential confounding by calendar period, sex assigned at birth, and age.

This cohort study was approved by the Knowledge Center for Data Reviews, Capital Region of Copenhagen. According to Danish legislation, individual informed consent is not required for register-based studies.

We obtained nationwide, longitudinal data from the Civil Registration System on all persons living in Denmark for at least 1 day between January 1, 1980, and December 31, 2021.¹⁴ Each resident has a unique 10-digit personal identifier, whose last digit reflects the recorded sex of the individual (uneven denotes male and even denotes female). This identifier allowed for identity-secure, individual-level linkage with data recorded in the National Patient Register, the Psychiatric Central Research Register, and the Register of Causes of Death.^15-17 In addition, a complete population extract of all historical changes, including changes reflecting a possible legal change of gender, was obtained from the Civil Registration System. Information on psychiatric and medical comorbidities was derived from the Psychiatric Central Research Register and the National Patient Register, where diagnoses were recorded according to the International Classification of Diseases (ICD). All register data were linked by Statistics Denmark, and to preserve confidentiality and adhere to Danish and European Union data protection regulations, a pseudonymized combined data set was used for the analyses.¹⁸

We applied a cohort design in which all Danish-born individuals aged 15 years or older were included. Individuals born outside the country were excluded because records of changes in personal identifiers among immigrants often reflect corrections of mistakes in the initial recording of the person’s sex, which could not be distinguished from a legal change of gender. Moreover, premigration factors, such as traumas and associated posttraumatic stress experienced by refugees, might influence an individual’s risk of suicide attempt and mortality independently of any gender identity–related issues.¹⁹

Cohort members were considered to be transgender if a hospital record suggested so, if the individual’s recorded sex had been changed in the Civil Registration System, or both.

Data from the Psychiatric Central Research Register since 1969 and the National Patient Register since 1977 were screened for any diagnostic codes suggesting a transgender or gender-diverse identity according to ICD-8 or ICD-10 (ICD-8: 302.39 and 302.59; ICD-10: F640, F642, F648, F649, Z768E, and Z768E1-Z768E4); ICD-9 was never implemented in Denmark. Information on outpatient and emergency department contacts was available since 1995. Individuals were considered to be transgender from the date when a transgender-related diagnostic code was first recorded.

Individuals aged 18 years or older who had been recorded once (and only once) with a legal change of gender since 1977 in the complete population extract from the Civil Registration System were considered to be transgender from the date of this change (Figure 1).

Individuals who were identified as transgender through both data sources were considered as transgender from the earliest of these events.

Individuals with medical comorbidity were those recorded in the National Patient Register as inpatient contacts during 1977 through 2021, as well as outpatient and emergency contacts during 1995 through 2021, with 1 or more medical disorders listed in the Charlson Comorbidity Index.²⁰ Psychiatric comorbidity was defined as 1 or more psychiatric hospital contacts as inpatients during 1969 through 2021 or outpatient and emergency contacts during 1995 through 2021 recorded in the Psychiatric Central Research Register or the National Patient Register, excluding contacts related to issues regarding gender identity or sexual orientation (ICD-8: 290-315, except 302; ICD-10: F00-F99, except F64-F66).

Suicide attempts were identified as hospital contacts in which such attempts were recorded as either the main or a secondary diagnosis (ICD-8: E950-E959; ICD-10: X60-X84) or the contact reason was listed as suicide attempt in a supplementary hospital coding system (code 4 or ALCC04). All suicide attempts recorded in connection with psychiatric (since 1969) or somatic (since 1977) hospital admissions or in connection with emergency department or outpatient contacts (since 1995), as listed in the Psychiatric Central Research Register or the National Patient Register, were included.

Deaths by suicide (ICD-8: E950-E959; ICD-10: X60-X84 and Y87.0) were identified in the Register of Causes of Death, which contains records of the causes of all deaths occurring in Denmark. A 92% agreement has been reported between official Danish suicide records and expert assessments.²¹ Suicide-unrelated deaths were defined as all deaths except suicide, and a joint outcome for any cause of death was also included.

We inspected visually the observation time among transgender individuals by calendar year and age group in a Lexis surface diagram.²² We calculated crude incidence rates (IRs) and indirectly standardized IRs per 100 000 person-years for period, sex assigned at birth, and age for the 4 study outcomes (suicide attempt, suicide death, suicide-unrelated death, and death by any cause), using the total population (ie, transgender and nontransgender individuals) as the reference population. For each outcome, regression models assuming a negative binomial distribution were used to compare IRs among transgender and nontransgender individuals by means of adjusted IR ratios (aIRRs). Standardized IR differences and aIRRs were calculated both overall and in strata of calendar period (1980-1989, 1990-1999, 2000-2009, and 2010-2021), sex assigned at birth (male and female), and age (15-24, 25-39, 40-59, 60-79, and ≥80 years), or merged categories hereof when numbers were limited. We considered aIRRs as statistically significant when the associated 2-sided 95% CIs excluded unity (1.0). With use of expected numbers of events derived from the estimation of the standardized IRs, 95% CIs were calculated for the standardized IR differences.²³ We had complete data for all covariates, all of which except sex assigned at birth were included as time-varying variables and updated on the exact date of change. Cohort members who emigrated or died were censored on the date of either of these events. In analyses of suicide attempts, cohort members were followed up until the date of a first suicide attempt, after which they were censored. In a sensitivity analysis, we calculated standardized IR differences and aIRRs restricting the transgender population to individuals identified as transgender through hospital records and to individuals identified as transgender through records of legal change of gender. Individuals identified in both data sources were included in both groups.

Because of the potential for type I error due to multiple comparisons, findings for the analyses should be interpreted as exploratory. All statistical analyses were conducted with the genmod and stdrate procedures in SAS version 9.4 (SAS Institute Inc).

In our cohort of 6 657 456 Danish-born individuals (50.0% assigned male sex at birth and 50.0% assigned female) who were observed during 171 023 873 person-years, a total of 3759 individuals (0.06%) were identified as having a transgender identity at a median age of 22 years (IQR, 18-31 years). Of these individuals, 1975 (52.5%) had been assigned male sex at birth (median age, 23 years; IQR, 19-31 years), and 1784 (47.5%) had been assigned female sex at birth (median age, 22 years; IQR, 17-31 years). The distribution of observation time (person-years) among transgender and nontransgender individuals is shown in Table 1. Among transgender individuals, 3495 (93.0%) had been recorded with a transgender-related diagnosis at a median age of 22 years (IQR, 18-31 years) at first relevant hospital contact, and 1581 (42.1%) had obtained a legal change of gender at a median age of 24 years (IQR, 20-32 years), implying that 1317 transgender individuals (35.0%) were identified through both data sources (Figure 1). Transgender individuals were observed during a total of 21 404 person-years. Observation time increased during calendar time from a total of 940 person-years in 1980-1989 to 13 978 person-years in 2012-2021 and was in recent years predominantly accrued among individuals aged 18 to 39 years (Figure 2).

During follow-up, hospital records of 1 or more suicide attempts were identified for 92 transgender individuals (median age at first attempt, 27 years; IQR, 19-40 years) and for 119 093 nontransgender individuals (median age at first attempt, 36 years; IQR, 23-50 years) (Table 2). Standardized IRs of suicide attempt per 100 000 person-years were 498 and 71 among transgender and nontransgender individuals, respectively, with a standardized IR difference of 428 (95% CI, 393-463) suicide attempts per 100 000 person-years. Adjusted for calendar period, sex assigned at birth, and age, transgender identity was associated with an aIRR for suicide attempt of 7.7 (95% CI, 5.9-10.2). Using rates among nontransgender individuals in the same calendar period as reference, aIRRs were 11.2 (95% CI, 6.0-20.9), 7.2 (95% CI, 3.7-14.0), 8.1 (95% CI, 4.9-13.3), and 6.6 (95% CI, 4.5-9.5) in 1980-1989, 1990-1999, 2000-2009, and 2010-2021, respectively. The IRs of suicide attempt were significantly elevated both among transgender individuals assigned male sex at birth (aIRR, 8.5; 95% CI, 6.2-11.7) and those assigned female sex at birth (aIRR, 6.8; 95% CI, 4.4-10.5) compared with nontransgender individuals of the same assigned sex at birth. Compared with nontransgender peers, IRs of suicide attempt were significantly higher for transgender individuals aged 15 to 24 years (aIRR, 6.6; 95% CI, 4.4-10.0), 25 to 39 years (aIRR, 8.8; 95% CI, 6.1-12.7), 40 to 59 years (aIRR, 7.1; 95% CI, 4.6-11.1), and 60 years or older (aIRR, 6.1; 95% CI, 2.5-14.7).

Twelve transgender individuals died by suicide (median age, 45 years; IQR, 35-50 years), whereas 36 308 suicides (median age, 52 years; IQR, 40-66 years) occurred among nontransgender individuals (Table 3). Standardized IRs of suicide mortality per 100 000 person-years were 75 among transgender individuals vs 21 among nontransgender individuals, resulting in a standardized IR difference of 54 (95% CI, 37-71) suicides per 100 000 person-years and an aIRR of 3.5 (95% CI, 2.0-6.3). Using rates among nontransgender individuals in the same calendar period as reference, aIRRs for suicide mortality were 5.4 (95% CI, 2.2-13.2) in 1980-1999 and 2.8 (95% CI, 1.3-5.9) in 2000-2021. Compared with that for nontransgender male individuals, the IR of suicide mortality was significantly higher among transgender individuals assigned male sex at birth (aIRR, 4.5; 95% CI, 2.6-8.0). There were no suicide deaths among transgender individuals assigned female sex at birth. The IRs of suicide mortality were significantly higher among transgender individuals aged 15 to 39 years (aIRR, 4.6; 95% CI, 1.9-11.2) and 40 years or older (aIRR, 3.1; 95% CI, 1.4-6.6) compared with similarly aged nontransgender individuals.

There were 245 deaths from suicide-unrelated causes among transgender individuals (median age, 70 years; IQR, 57-80 years) vs 2 240 198 nonsuicidal deaths (median age, 78 years; IQR, 68-85 years) among nontransgender individuals (Table 3). Standardized IRs of suicide-unrelated mortality per 100 000 person-years were 2380 among transgender individuals vs 1310 among nontransgender individuals, with a standardized IR difference of 1070 (95% CI, 963-1176) suicide-unrelated deaths per 100 000 person-years and an aIRR of 1.9 (95% CI, 1.6-2.2). Using IRs for nontransgender individuals in the same calendar periods as reference, aIRRs were significantly elevated during 1980-1999 (aIRR, 2.3; 95% CI, 1.7-3.0) and 2000-2021 (aIRR, 1.7; 95% CI, 1.5-2.1). Compared with those of nontransgender individuals with the same assigned sex at birth, IRs of nonsuicidal mortality were significantly increased for transgender individuals assigned male sex at birth (aIRR, 1.8; 95% CI, 1.5-2.1) and for those assigned female sex at birth (aIRR, 2.0; 95% CI, 1.6-2.5). When same-aged nontransgender individuals were used as reference, the IRs of suicide-unrelated mortality was significantly higher for transgender individuals aged 40 to 59 years (aIRR, 2.5; 95% CI, 1.9-3.2), 60 to 79 years (aIRR, 1.6; 95% CI, 1.3-2.0), and 80 years or older (aIRR, 1.8; 95% CI, 1.4-2.3).

Overall, 257 deaths from any cause were observed among transgender individuals (median age, 67 years; IQR, 56-80 years) vs 2 276 506 deaths (median age, 78 years; IQR, 68-85 years) among nontransgender individuals (Table 3). Standardized IRs for all-cause mortality per 100 000 person-years were 2559 among transgender individuals vs 1331 among nontransgender individuals, with a standardized IR difference of 1227 (95% CI, 1122-1333) deaths per 100 000 person-years and an aIRR of 2.0 (95% CI, 1.7-2.4). Elevated IRs for all-cause mortality were observed for transgender individuals in 1980-1989 (aIRR, 2.2; 95% CI, 1.3-3.7), 1990-1999 (aIRR, 2.4; 95% CI, 1.8-3.3), 2000-2009 (aIRR, 2.1; 95% CI, 1.6-2.8), and 2010-2021 (aIRR, 1.7; 95% CI, 1.4-2.1) when using nontransgender individuals in the same calendar periods as reference. Compared with nontransgender individuals assigned the same sex at birth, IRs for all-cause mortality were significantly increased for transgender individuals assigned male sex at birth (aIRR, 1.9; 95% CI, 1.6-2.3) and for those assigned female sex at birth (aIRR, 2.1; 95% CI, 1.7-2.6). When similarly aged nontransgender peers were used as reference, IRs for all-cause mortality were significantly higher for transgender individuals aged 15 to 39 years (aIRR, 2.2; 95% CI, 1.3-3.8), 40 to 59 years (aIRR, 2.6; 95% CI, 2.1-3.4), 60 to 79 years (aIRR, 1.7; 95% CI, 1.4-2.1), and 80 years or older (aIRR, 1.8; 95% CI, 1.4-2.3).

Compared with that of nontransgender individuals, significantly elevated IRs of suicide attempt were observed among both hospital record–identified transgender individuals (aIRR, 8.6; 95% CI, 6.4-11.4) and those identified through administrative records of legal change of gender (aIRR, 5.2; 95% CI, 3.3-8.0) (eTable in Supplement 1). A significantly higher IR of suicide mortality (aIRR, 4.0; 95% CI, 2.2-7.2) was observed among hospital record–identified transgender individuals, whereas fewer than 3 suicide deaths were observed among those identified through records of legal change of gender. For suicide-unrelated mortality, the IR was significantly elevated for hospital record–identified transgender individuals (aIRR, 1.9; 95% CI, 1.6-2.2), but not for those identified through administrative records (aIRR, 1.1; 95% CI, 0.8-1.5). For all-cause mortality, the IR was significantly higher for hospital record–identified transgender individuals (aIRR, 2.0; 95% CI, 1.8-2.4), but not for those identified through administrative records (aIRR, 1.1; 95% CI, 0.8-1.5).

In this national cohort study covering 42 years of observation, overall rates of suicide attempt, suicide mortality, suicide-unrelated mortality, and all-cause mortality were consistently higher among transgender than nontransgender individuals after controlling for calendar period, sex assigned at birth, and age. These findings were confirmed for suicide attempt and suicide-unrelated and all-cause mortality in analyses stratified by sex assigned at birth. Despite generally declining rates over time for all 4 outcomes among both transgender and nontransgender individuals living in Denmark, aIRRs remained statistically significantly elevated throughout the study period, reflecting a persistently higher risk of suicide attempt and mortality among transgender individuals.

Between 1980 and 2021, an increasing prevalence of transgender individuals was observed, which is in accordance with clinical reports and systematic reviews.^24,25 This trend has been linked to a stronger presence of transgender role models in the media, destigmatization, and increased societal openness toward gender identity issues.²⁵ The legislation regarding legal change of gender in Denmark was introduced only in 2014,⁶ which may explain the modest overlap between hospital record–identified transgender individuals and those identified through administrative records of legal change of gender. Having used data from 2 independent sources to identify transgender individuals adds to the reliability of the obtained estimates.

To our knowledge, national rates of suicide attempt and suicide mortality have not previously been reported for transgender individuals. The increased rate of suicide attempt observed among transgender individuals accords with baseline findings from 2017 to 2018 in a large, nationwide cohort study from Denmark, in which 23% to 24% of transgender individuals reported at least 1 lifetime suicide attempt compared with 2% to 4% among nontransgender peers.⁴ The suicide mortality rate observed for transgender individuals in the present study is similar to that reported for transgender individuals attending a clinic for gender dysphoria in Amsterdam, the Netherlands, during 1972 to 2017 (53 per 100 000 person-years), which was considered to be higher than the rate in the general Dutch population.²⁶ An even higher suicide mortality rate (270 per 100 000 person-years) was reported for Swedish transgender individuals undergoing gender identity–affirming surgery during 1973 to 2003.¹¹ A recent population-based study using data from general practitioners and death statistics in England between 1988 and 2019 reported 3 to 5 times increased mortality from either suicide or homicide among transgender and gender-diverse individuals compared with nontransgender individuals.²⁷

Well in line with the current findings, higher rates of suicide-unrelated and all-cause mortality compared with those of the general population have been reported for transgender individuals attending a clinic for cross-sex hormone treatment in the Netherlands between 1972 and 2018.¹⁰ In England, all-cause mortality rates among transgender and gender-diverse individuals were increased between 1.3- and 1.7-fold between 1988 and 2019 compared with that of nontransgender individuals.²⁷ Elevated rates of all-cause mortality among transgender individuals have also been reported in studies from Sweden¹¹ and the United States.²⁸ In contrast, and despite a higher suicide mortality rate during 1999 to 2016, transgender US veterans had 10% lower all-cause mortality compared with other veterans.⁹

The observed excess of suicidal behavior and mortality might, at least in part, constitute ramifications of minority stress. Transgender individuals may be exposed to systemic negativity regarding their trans identity in the form of bullying, discrimination, exclusion, and prejudice, which in turn may result in alienation and internalized stigma, mental health problems, and, ultimately, suicidal behavior.^4,8,29-31 For instance, findings from the Project SEXUS study in Denmark revealed that 60% of transgender individuals had experienced abuse in the form of bullying or harassment, whereas 30% reported episodes of physical violence.⁴ In the 2015 US Transgender Survey, 46% of transgender individuals reported having been verbally harassed and 13% reported having been physically attacked within the past year.³² Moreover, transgender individuals have reported experiences of discrimination from health professionals.^30,33

Efforts to reduce suicidality among transgender individuals are recommended. These could include direct measures, such as encouragements to seek help in situations of personal distress, and general measures have been suggested to reduce structural discrimination, such as the implementation of training and best practice guidelines among health care professionals and the wider use of gender-neutral public bathrooms and locker rooms.^34-36

This study has several limitations. First, the findings may not be generalizable to transgender individuals who have never received hospital care for gender identity–related issues or applied for legal change of gender. Second, being restricted to Danish-born individuals, the findings may not necessarily apply to transgender individuals born elsewhere. Third, hospital codes used to identify transgender individuals carry descriptions that may have been perceived as stigmatizing, which might have reduced their use among some health professionals. Fourth, although transgender individuals might have considered themselves as being transgender since childhood or adolescence, they were here considered as such from the date of a first hospital record or legal change of gender. Fifth, because of their likely role as intermediate variables in the causal pathway between the exposure and the studied outcomes, mental and physical comorbidities were not included as covariates in the analyses. Consequently, the reported aIRRs reflect overall associations of transgender identity with suicide attempt and mortality, which may well differ between subgroups of transgender individuals with and without comorbidities. Sixth, suicide attempts are underrecorded in Danish hospital records.³⁷ Consequently, to the extent transgender individuals differ from nontransgender individuals in their hospital-seeking behavior after self-harming, the reported aIRRs of suicide attempt may be somewhat too high or too low.

In this population-based, retrospective cohort study, transgender individuals identified through hospital records and administrative records of legal change of gender had significantly higher rates of suicide attempt, suicide mortality, suicide-unrelated mortality, and all-cause mortality compared with the nontransgender population.

Accepted for Publication: May 2, 2023.

Corresponding Author: Annette Erlangsen, PhD, Danish Research Institute for Suicide Prevention, Mental Health Centre Copenhagen, Gentofte Hospitalsvej 15, DK-2900 Hellerup, Denmark (annette.erlangsen@regionh.dk).

Author Contributions: Dr Erlangsen had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Erlangsen, Nordentoft, Frisch.

Acquisition, analysis, or interpretation of data: Erlangsen, Jacobsen, Ranning, Delamare, Frisch.

Drafting of the manuscript: Erlangsen.

Critical revision of the manuscript for important intellectual content: Jacobsen, Ranning, Delamare, Nordentoft, Frisch.

Statistical analysis: Erlangsen.

Obtained funding: Erlangsen.

Administrative, technical, or material support: Erlangsen, Nordentoft.

Supervision: Nordentoft, Frisch.

Conflict of Interest Disclosures: Dr Erlangsen reported receiving grants from the Danish Health Foundation (20-B-0359) during the conduct of the study. No other disclosures were reported.

Funding/Support: The project was supported by a research grant from the Danish Health Foundation (20-B-0359).

Role of the Funder/Sponsor: The Danish Health Foundation had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Data Sharing Statement: See Supplement 2.