Author's Accepted Manuscript

Sports Related sudden Cardiac Death in a Compe-titive and Non-competitive Athlete Population aged12�49 years: Data from an unselected Nationwidestudy in Denmark

Bjarke Risgaard MD, Bo Gregers Winkel MD, PHD,Reza Jabbari MD, Charlotte Glinge BM, OleIngemann-Hansen MD, PHD, Jørgen LangeThomsen MD, DMSc, Gyda Lolk Ottesen MD,DMSc, Stig Haunsø MD, DMSc, Anders GaarsdalHolst MD, PHD, Jacob Tfelt-Hansen MD, DMSc

PII: S1547-5271(14)00557-8DOI: http://dx.doi.org/10.1016/j.hrthm.2014.05.026Reference: HRTHM5789

To appear in: Heart Rhythm

Cite this article as: Bjarke Risgaard MD, Bo Gregers Winkel MD, PHD, Reza JabbariMD, Charlotte Glinge BM, Ole Ingemann-Hansen MD, PHD, Jørgen Lange ThomsenMD, DMSc, Gyda Lolk Ottesen MD, DMSc, Stig Haunsø MD, DMSc, Anders GaarsdalHolst MD, PHD, Jacob Tfelt-Hansen MD, DMSc, Sports Related sudden Cardiac Deathin a Competitive and Non-competitive Athlete Population aged 12�49 years: Data froman unselected Nationwide study in Denmark, Heart Rhythm, http://dx.doi.org/10.1016/j.hrthm.2014.05.026

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Sports related sudden cardiac death in a competitive and non-competitive athlete

population aged 12−49 years:

Data from an unselected nationwide study in Denmark

Bjarke Risgaard, MD1,2*

; Bo Gregers Winkel, MD, PHD1,2

; Reza Jabbari, MD1,2

; Charlotte Glinge, BM1,2

,

Ole Ingemann-Hansen, MD, PHD3; Jørgen Lange Thomsen, MD, DMSc

4; Gyda Lolk Ottesen, MD, DMSc

5;

Stig Haunsø, MD, DMSc1,2,6

; Anders Gaarsdal Holst, MD, PHD1,2

; Jacob Tfelt-Hansen, MD, DMSc1,2

Affiliations: 1The Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), Copenhagen,

Denmark; 2Laboratory of Molecular Cardiology, Department of Cardiology, The Heart Centre, Copenhagen University

Hospital Rigshospitalet, Copenhagen, Denmark; 3Department of Forensic Medicine, Aarhus University, Aarhus,

Denmark; 4Institute of Forensic Medicine, University of Southern Denmark, Odense, Denmark; 5Department of

Forensic Medicine, University of Copenhagen, Copenhagen, Denmark; and 6Department of Medicine and Surgery,

Faculty of Health Science, University of Copenhagen, Copenhagen, Denmark

Wordcount: 4744

Conflict of interest

AGH is an employee of Novo Nordisk A/S, Søborg, Denmark.

*Corresponding author: Bjarke Risgaard, MD. Address for correspondence: Laboratory of Molecular Cardiology, The

Heart Centre, Copenhagen University Hospital, Rigshospitalet, 9312, Juliane Maries Vej 20, 2100 Copenhagen Ø.

Tel: (+45) 35 45 65 01 Fax: (+45) 35 45 65 00 Email: bjarkerisgaard@gmail.com

2

Abstract

Background: Preparticipation screening programs have been suggested to reduce the numbers of sports

related sudden cardiac deaths (SrSCD).

Objective: To identify and characterize all SrSCD aged 12−49 years and to address the difference in

incidence rates between competitive and non-competitive athletes.

Methods: All deaths in persons aged 12−49 years in 2007−2009 were included. Death certificates were

reviewed. History of previous admissions to hospital was assessed, discharge summaries, and autopsy reports

were read. Sudden cardiac deaths (SCD) and SrSCD cases were identified.

Results: In the 3-year period there were 881 SCD of which we identified 44 SrSCD. In non-competitive

athletes aged 12−35 years the incidence rate of SrSCD was 0.43 (95% CI: 0.16 to 0.94) per 100,000 athlete

person-years whereas it was 2.95 (95% CI: 1.95 to 4.30) in non-competitive athletes aged 36−49 years. In

competitive athletes the incidence rate of SrSCD was 0.47 (95% CI: 0.10 to 1.14) and 6.64 (95% CI: 2.86 to

13.1) per 100,000 athlete person-years in those aged 12−35 years and 36−49 years, respectively. The

incidence rate of SCD in the general population was 10.7 (95% CI: 10.0 to 11.5) per 100.000 person-years.

Conclusion: The incidence rates of SrSCD in non-competitive and competitive athletes are not different. The

study showed an increase in the incidence rate of SrSCD in persons aged 36−49 years in both non-

competitive and competitive athletes compared to those aged 12−35 years. Importantly, SCD in the general

population is much more prevalent than SrSCD in all age groups.

Key words: Sudden cardiac death; Athletes; epidemiology, preparticipation screening

Abbreviations

ARVC – Arrhythmogenic right ventricular cardiomyopathy

CAD – coronary artery disease

HCM – Hypertrophic cardiomyopathy

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SCD – Sudden cardiac death

SrSCD – Sports related sudden cardiac death

SUD – Sudden unexplained death

Introduction

Sports-related sudden cardiac deaths (SrSCD) are tragic occurrences that receive significant media attention

and have become highly debated public health issues.(1) Several epidemiological studies on SrSCD in young

competitive athletes have estimated the incidence rate, the causes, and the proportion of these deaths that are

potentially preventable.(2–6) In this regard, it is heavily debated if preparticipation screening programs

prevent some of these deaths.(1,7) Data that favours such a strategy mainly comes from a prospective,

initially retrospective, Italian study in which it has been shown that preparticipation screening lowers the

incidence rate of SrSCD in young competitive athletes.(3) However, several other studies have suggested

that screening will be of limited value.(1,2,6,8,9) Today, preparticipation screening programs are

recommended by the European Society of Cardiology (10) and have been implemented on different levels in

many countries with the most extensive ones in Italy and Israel.(2,3)

According to the most frequently used definition, initially proposed by Maron and colleagues,(11) a

competitive athlete is a person who participates in individual sports or in an organized team that requires

systematic training and regular competition against others. On the other hand, non-competitive athletes

participates in a variety of recreational sports activities within a wide range of exercise levels ranging from

moderate to vigorous activity.(7) Until now, studies on SrSCD have mainly been conducted on competitive

athletic populations aged less than 35 years(3–6,8,12). While studies on SrSCD during non-competitive

athletic activities remain sparse(13,14), it has been shown that the risk of cardiac arrest is transiently

increased during vigorous exercise, but that habitual exercise is associated with an overall decreased

mortality.(15)

To our knowledge, only one study has prospectively evaluated the incidence rate of all sports related sudden

deaths (SD).(12) To fully understand the epidemiology of sports related SrSCD, several issues still need to

be addressed. First, the incidence rate of SrSCD in the non-competitive athletic population is unknown.

4

Second, it is not known whether non-competitive athletes are in a higher risk of SrSCD than competitive

athletes. Third, studies on SrSCD in competitive athletes have mainly been conducted on young individuals,

and incidence rates for the population aged >35 years is largely unknown.

We have previously identified all sudden cardiac deaths (SCD) including all SrSCD in competitive athletes

aged 12-35 years in Denmark 2000-2006.(6,16) The aim of this first nationwide study on persons aged

12−49 years was to identify and characterize all SrSCD and to address the difference in incidence rates

between competitive and non-competitive athletes.

Methods

Study design

The methods used for this study have previously been described in detail.(17) In short, this is a nationwide

retrospective study using the availability of all death certificates, the registration of all in- and outpatient

activity in Danish hospitals and emergency rooms together with access to all medical records and autopsy

reports. We included all deaths in a 3-year period (2007−2009) in persons aged 12−49 years. The study was

approved by the local ethics committee (H−KF−272484), The Danish Data Protection Agency

(2011−41−5767), and the Danish National Board of Health (7−505−29−58/6).

Danish registries:

All Danish citizens have a unique and personal civil registration number which can be linked to national

registries on an individual level. The Danish National Patient Registry contains information on all in- and

outpatient activities in Denmark since 1978. Diagnoses are coded according to the corresponding

International Classification of Diseases, the 8th revision (ICD-8) until 1993 and since 1994 the 10

th revision

(ICD-10) has been used.

Review of death certificates:

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Death certificates were read independently by two physicians in order to identify deaths that were sudden

and unexpected. In case of disagreement a consensus were reached after re-evaluating the circumstances

surrounding the death, including a review of previous medical history which was taken into account in every

single case. Danish death certificates are informative and suitable to identify sudden unexpected deaths as

they have a supplemental information field (see supp. Data, Winkel et. al (16)). This field contains

information describing circumstances surrounding the death including interviews with eyewitnesses and

relatives, previous medical conditions, an external examination of the body, and the preliminary conclusion

before autopsy. This field is mandatory in all medico-legal external examinations (external examinations),

including cases in which it is decided not to conduct an autopsy. The Danish Death certificates can only be

issued by a medical doctor. In cases where citizens or patients are found dead and/or the death is sudden and

unexpected, external examinations are mandatory by law. Information from these examinations can be found

in the supplemental information field on the Danish death certificate. Due to this great level of detail, the

Danish death certificates are highly suitable to identify cases of sudden unexpected death during sports.

Discharge summaries:

Discharge summaries were available through an electronic hospital records system. We had access to

information describing the time surrounding the death, including a description of the treatment and

management in the emergency room or hospital department. Discharge summaries were also available from

the prehospital trauma and emergency doctors.

Conduct of autopsies:

In Denmark there are three forensic departments conducting around 1500 autopsies per year. All forensic

autopsies are supervised by another forensic pathologist and follow a protocol in which all organs are

thoroughly examined. Toxicology screens are performed in unexplained adolescent and adult cases of

sudden unexpected death. Cardiac pathologists are available if deemed necessary.

Definitions

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We defined the sudden unexpected death as the sudden, natural unexpected death; in witnessed cases as an

acute change in cardiovascular status with time to death being <1 h and in unwitnessed cases as a person last

seen alive and functioning normally <24 h before being found dead.

Sudden cardiac death (SCD) in autopsied cases was defined as the natural unexpected death of unknown or

cardiac cause; in witnessed cases as an acute change in cardiovascular status with time to death being <1 and

in unwitnessed cases as a person last seen alive and functioning normally <24 h before being found

dead.(16–19)

Autopsied SCD was subdivided in two groups: 1) Explained SCD, in which a cardiac cause of death was

established and 2) Sudden unexplained death (SUD), where causes of death after autopsy remained

unknown.

In non-autopsied deaths the same criteria were used in cases presumed to be of cardiac origin based on the

circumstances relating to the death including all information from death certificates and discharge

summaries. Non-autopsied cases with no competing causes of death were considered to be of cardiac origin.

SrSCD was defined as a SCD occurring during or within 1 hour after moderate- to high-intensity exercise.

Using all the information available, we subdivided SrSCD into whether the deceased was considered a

competitive or non-competitive athlete. The deceased was considered a competitive athlete if he or she did

moderate to high intensity sports on a regular level and took part in competitions. For the purpose of this

study, a non-competitive athlete was defined as a person not participating in competitions, but who did

moderate to high intensity sports on a regular level in the months prior to death.

Media search

To apply a method used by others when identifying SrSCD, an additional extensive retrospective media

search was performed as a supplement to the main approach. The Danish media surveillance database

Infomedia (www.infomedia.dk), a database of approximately 400 printed, 2,200 web-based, and the major

radio and television Danish media, was used.

Sport activities in the general population

7

To estimate the size of the background population performing competitive and non-competitive sports

activities, on a regular level (the denominator), we used data from the Danish National Institute of Public

Health.(20) They conducted, in collaboration with the five regions of Denmark, the Ministry of Interior and

Public Health, a major study “How are you?” from 2010 in which they, among other things, investigated the

occurrence of physical activity in Denmark. Through questionnaires they collected information on physical

activity throughout the country from persons aged 16 years and above.

The respondents were asked to choose one of the following categories fitting their daily activity level the

best; 1) Doing hard exercise at a competition level regularly several times a week, 2) Doing recreational

sports or hard physical demanding work at least 4 hours a week, 3) Walking, biking, or doing other less

demanding recreation sports at least 4 hours a week, or 4) Reading, watching television or doing other

sedentary activities. All data were stratified on age, gender, geographic area, education, civil status as well as

ethnicity and weighted for non-response by statistic Denmark.(21)

For the purpose of this study, respondents choosing category one was considered competitive athletes, and

respondents choosing category two was considered non-competitive athletes. As the age range in the “How

are you?” study not matched ours, the assumption was made, that we could extrapolate information from the

population aged 16−49 years to the population aged 12−49 years.

Cardiac symptoms prior to death

We defined prodromal symptoms as symptoms in the hours to minutes leading up to the death and

antecedent symptoms as symptoms in the years to days leading up to the death. Previous contacts to general

practitioners with cardiac symptoms were investigated by collecting all records as previously described in

detail.(22)

Statistical analysis

All calculations and data analysis were performed with the use of Stata software package (StataCorp,

Collage Station, Texas, version 11.0). Incidence rates were calculated using the mean age group population

as a denominator. Confidence intervals for incidence rates were calculated using the Poisson distribution.

8

Sensitivity analysis was carried out using autopsied cases only. Categorized nominal data were compared

using the chi-square test. If any cell values were <5, the Fisher exact test was used. Medians were compared

using the Wilcoxon rank-sum test. We considered a two sided p-value <0.05 to be statistically significant.

Results

Review of death certificates

In the study period, Denmark had a mean population of 5.48 million inhabitants, of whom, 2.73 million were

aged 12−49 years equalling 8.20 million person-years for the three year study period. From 2007−2009 there

were 8085 deaths among persons aged 12−49 years. There were 7616 death certificates issued during this

period. The 469 death certificates missing represented foreigners or Danes dying outside Danish borders.

Twenty-six (<1%) cases were initially excluded due to incomplete data on the death certificate (figure 1).

Media search

By searching the national media database through 2007−2009, we identified and read 580 relevant articles.

The following search query was used (in Danish); Cardiac arrest (258 hits), Cardiac death (86 hits), Sports

death (11 hits), Sudden death (115 hits), and drop dead (110 hits). We identified 11 SrSCD occurring outside

Danish borders, and 7 cases inside Danish borders. Five of these 7 cases were not included in this study due

to successful resuscitation (n = 2), and age >49 years (n = 3).

Sports related sudden cardiac death population

From the review of the death certificates, registry information on previous medical history, discharge

summaries, and the media search we identified 881 SCD of which 44 cases were SrSCD. Thirty-three of the

44 SrSCD occurred in a non-competitive athlete whereas 11 cases occurred in a competitive athlete (figure

2). Of the 2 cases identified through media search, one was identified from the review of the death

certificates. The remaining case was identified and included after review of discharge summaries among the

26 cases with incomplete death certificate data (page 2 of death certificate missing, figure 1.

Sport activities in Denmark

9

The Danish National Institute of Public Health received 172,639 questionnaires (60% of those invited).

Based on 96,075 questionnaires, received from persons aged 16−49 years, we estimated the size of the non-

competitive and competitive athlete population in the background population. Overall, 8.9% and 28.1% were

classified as competitive and non-competitive athletes, respectively. This equals to 730,166 competitive

athletic person-years and 2,305,355 non-competitive athletic person-years for the 3-year study period (table

1).

Incidence rates

In persons aged 12−49 years we report an incidence rate of SrSCD in the general population of 0.54 (95%

confidence interval [CI]: 0.39 to 0.72) per 100,000 person-years. The incidence rate of SCD in the general

population was 10.7 (95% CI: 10.0 to 11.5) using the same methodology.

In non-competitive athletes aged 12−35 years the incidence rate of SrSCD was 0.43 (95% CI: 0.16 to 0.94)

per 100,000 athlete person-years whereas it was 2.95 (95% CI: 1.95 to 4.30) in those aged 36-49 years. In

competitive athletes the incidence rate of SrSCD was 0.47 (95% CI: 0.10 to 1.14) and 6.64 (95% CI: 2.86 to

13.1) per 100,000 athlete person-years in those aged 12−35 years and 36-49 years, respectively.

The incidence rate of SCD in the general population was 3.15 (95% CI: 2.67 to 3.69) per 100.000 person-

years in those aged 12−35 years and it was 21.7 (95% CI: 20.1-23.4) per 100.000 person-years in those 36 to

49 years (table 1).

Characterisation of SrSCD in competitive and non-competitive athletes

Forty-four cases of SrSCD were identified in the 3-year study period with a median of 16 cases per year

(range 12−16). The median age was 41.5 years (range 12−49 years, mean 38 years) and there were a marked

male predominance (n=41, 93%) (See clinical characteristics in table 2 and table 3).

The predominant sport was running (n=17) followed by cycling (n=13). In 33 out of 44 (75%) cases, death

occurred during non-competitive athlete activities. In 30 out of 44 (68%) cases death occurred in a public

area; in 33 of 44 (75%) cases death was witnessed. Prodromal symptoms were observed in 16 out of 33

(48%) witnessed cases, and antecedent symptoms were reported in 21 out of 44 (47%) cases.

10

An autopsy was conducted in 35 of 44 cases (autopsy ratio 80%). After review of the autopsy reports, 15

deaths were found to be caused by coronary artery disease (CAD), 5 were caused by arrhythmogenic right

ventricular cardiomyopathy (ARVC), 4 were caused by hypertrophic heart (HH), 4 were sudden and

unexplained (SUD), 2 were caused by myocarditis, and 1 was caused by each of the following: valve disease,

malformation of coronary artery, hypertrophic cardiomyopathy (HCM), congenital heart disease, and non-

concentric hypertrophy of left ventricle. In the 4 cases of HH, left ventricular hypertrophy was found, but no

definite diagnoses of HCM could be made as the histopathology showed no signs of disarray of the

myofibrils. In supplemental material, see comparisons of SrSCD in competitive and non-competitive athletes

as well as macroscopic and histological definitions.

Discussion

Using death certificates, registry entries, discharge summaries, and a media search along with autopsy

reports we have conducted a study on SrSCD in Denmark 2007−2009 in the age group 12-49 years. The aim

was to identify and characterize all SrSCD and to address the difference in incidence rates between

competitive and non-competitive athletes. We found 44 SrSCD of which 33 deaths occurred in a non-

competitive athlete. This equals an overall incidence rate of SrSCD in the general population of 0.54 per

100,000 person-years. In the non-competitive and competitive athlete populations the incidence rate of

SrSCD was 1.43 and 1.51 per 100,000 athlete person-years, respectively. In contrast, the incidence rate of

SCD in the general population was 10.7 per 100,000 person-years.

Risk of SrSCD during sports

There is an on-going debate whether competitive athletes are at increased risk of SrSCD, but also whether

recreational sport activities confer an increased risk.(12,14,15,23,24) Physical activity may be regarded as a

“two-edged sword” as vigorous exercise acutely increases the risk of SCD,(25) while physical activity in the

long-term may offer protection against several cardiovascular diseases.(23,26)

11

In France, it has recently prospectively been shown that SD during sports more often occur in young

competitive athletes compared to young non-competitive participants (0.98 vs. 0.22 per 100,000 person-

years).(12) However, although prospective in design, Marijon and colleagues calculated the incidence rates

for non-competitive athletes using the general population as the denominator. As mentioned by the authors

themselves, they had variability in the reported incidence rates throughout the country, and this might be

explained by some degree of underreporting.

We find that SrSCD in Denmark is uncommon. In young competitive athletes aged 12−35 years, we report a

very low incidence rate of 0.47 per 100,000 athlete person-years. This is lower than we have previously

reported in Denmark (1.21 per 100,000), but also lower than Minnesota (0.93 per 100,000), the Veneto

region (0.87 per 100,000), France (0.98 per 100,000) and in the entire United States (0.61 per 100,000).(3–

6,8,12) In competitive athletes aged 36-49 years there is a significantly higher incidence rate of SrSCD

reaching 6.64 per 100.000 person-years (table 1). To our knowledge, incidence rates of SrSCD in competitive

athletes have not previously been reported in this age group. In young non-competitive athletes, we also

report a significantly higher incidence rate of SrSCD in those aged 36−49 years compared to those aged 12-

35 years; 2.95 vs. 0.43 per 100.000 athlete person-years. It is noteworthy, that the incidence rate of SCD in

the general population was much higher reaching 3.15 per 100.000 person-years in those aged 12−35 years

and 21.7 per 100.000 person-years in those aged 36−49 years. Like previous studies, we find a male

predominance.(6,27)

Preparticipation screening programs

In order to reduce the burden of SrSCD in competitive athletes, there has been an increasing focus on the

most realistic and optimal strategy for mass preparticipation screening programs. On one side the Italian

investigators have implemented and promoted nationally mandated screening programs of all athletes with

routine electrocardiograms (ECGs) and a medical examination. In the Veneto region they have shown that

after the implementation of the mandatory preparticipation screening program, launched in the 1980s, the

incidence rate of SrSCD in the competitive athletes have declined remarkably.(3) On the other hand the

12

American Heart Association have underscored the many obstacles in administering a massive and expensive

program with little or doubtful effect.(28,29)

Even though preparticipation screening programs has been debated for several years, knowledge on

outcomes, risks and benefits of screening, and cost efficiency remain incomplete.(1) In Denmark, it has

recently been proposed that screening of competitive athletes probably will be of limited value, and

screening is not recommended by the Danish Society of Cardiology.(6,30) That is, no systematic screening

of athletes has been in place during or before the study period. However, due to requirements from, for

example, the Union of European Football Associations preparticipation screening of a small group of athletes

has been carried out in the study period.

To determine whether mass preparticipation screening should be recommended, we decided to measure, on a

nationwide basis, the incidence rate of SrSCD in non-competitive and competitive athletes aged 12-49. This

has not been done before. Typically, pre-participation screening programs are only available to those young

people who choose to be involved in competitive sports. However, the current results suggest that being a

non-competitive athlete confers the same risk of SrSCD. Hence, it is questionable whether these programs, if

recommended, only should be available to those who choose to do sports on a competitive level.

Furthermore, the current findings suggest that SCD in the general population is much more common than

SrSCD and it might be argued that it would be ethically unacceptable to screen only those participating in

sports and not the general population.(31)

We believe that the present study indicate that screening probably will be of limited value. Most

preparticipation programs are only available to those who are young, and those who choose to do

competitive sports, which cannot, in our point of view, be ethically acceptable. Furthermore and importantly,

the present study indicates that the majority of these deaths could not have been prevented by screening with

an ECG and a physical examination. That is, we believe that only 12 of these cardiac diseases would be

potentially detectable (ARVC [5], HH [4], valve disease [1], HCM [1], congenital heart disease [1]).

13

We found that prodromal symptoms were observed in 16 out of 33 (48%) witnessed cases, and antecedent

symptoms were reported in 21 out of 44 (46%) cases, suggesting that raising awareness on symptoms during

sport among athletes may present an alternative strategy for preventions of SrSCD.

Limitation

It is a limitation that the study was retrospective. We used data from questionnaires from the Danish

National Institute of Public Health, to estimate the non-competitive and competitive athlete background

population in Denmark. As the age range not matched ours, the assumption was made, that we could

extrapolate information from the population aged 16−49 years to the population aged 12−49 years.

Furthermore, the assumption was made that the information from this survey from 2010 could be

extrapolated to the years 2007−2009. The present study does not provide any insight into arrhythmia

mechanisms of a SrSCD. It is a limitation that 26 (0.3%) death certificates were incomplete. As shown in the

sensitivity analysis, lack of autopsies brings some uncertainty into estimates of the SrSCD incidence rates.

Not all SrSCD cases were evaluated by a pathologist with expertise in sports-cardiology.

To conclude, the present study suggests that preparticipation screening will be of limited value, and probably

ethically unacceptable, if only provided to those (young people) who choose to be involved in competitive

sports. Cardiac symptoms prior to death are often found, suggesting that raising awareness on symptoms

during sport among athletes may present an alternative strategy for preventions of SrSCD.

Funding Sources

This work was supported by the Danish National Research Foundation Centre for Cardiac Arrhythmia

(DARC), University of Copenhagen, Copenhagen, Denmark; Laboratory of Molecular Cardiology, The

Heart Centre, Department of Cardiology, University Hospital Rigshospitalet, Copenhagen, Denmark; The

John and Birthe Meyer Foundation; The Danish Heart Foundation (12-04-R91-A3790-22689); The Research

Fund of Rigshospitalet, Copenhagen University Hospital.

14

Acknowledgement

The Danish Health Profile 2010 was funded by The Capital Region, Region Zealand, The South Denmark

Region, The Central Denmark Region, The North Denmark Region, The Danish Ministry of Interior and

Health, and the National Institute of Public Health, University of Southern Denmark.

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17

Figure legends

Figure 1: Title: Flowchart – Flowchart of the identification of all sudden unexpected deaths and all sports

related sudden cardiac deaths in persons aged 12-49 years in Denmark 2007-2009

18

Figure 2: Title Age distribution – Age-related distribution of 44 sports related sudden cardiac deaths in

persons aged 12-49 years in Denmark 2007-2009. Bars representing competitive athletes are always placed

above the non-competitive athletes, representing 0 to 2 deaths in each age range.

19

Tables

Table 1: Sports-related sudden cardiac death by different age groups in Denmark 2007-2009

*SCD, sudden cardiac death; †SrSCD, sports related sudden cardiac death;

Age group (years) 12-49 12-35 36-49

SrSCD† cases (n) 44 9 35

Of whom were competitive athletes (n) 11 3 8

Age group population, in thousands 2,735 1,618 1,116

Active competitive athletes* 8.9% 13.2% 3.6%

Active non-competitive athletes* 28.1% 28.7% 27.3%

Incidence rates per 100.000 person-years

(denominator) (95% CI) (95% CI) (95% CI)

SCD* (general population) 10.7 (10.0-11.5)

3.15 (2.67-

3.69) 21.7 (20.1-23.4)

SrSCD† (general population) 0.54 (0.39-0.72)

0.19 (0.08-

0.35) 1.05 (0.73-1.45)

Non-competitive athletes (non-competitive athletes) 1.43 (0.99-2.01) 0.43 (0.16-

0.94) 2.95 (1.95-4.30)

Competitive athletes (competitive athletes) 1.51 (0.75-2.71) 0.47 (0.10-

1.14) 6.64 (2.86-13.1)

Sensitivity analyses: Incidence rates per 100,000

person-years (denominator)

Autopsied cases only:

Non-competitive athletes (non-competitive

athletes) 1.08 (0.6-2.5)

0.43 (0.16-

0.94) 2.08 (2.3-12.0)

Competitive athletes (competitive athletes) 1.37 (0.7-1.6) 0.47 (0.10-

1.14) 5.81 (1.3-3.3)

20

Table 2: Characterisation of sports-related sudden deaths in non-competitive athletes by age in Denmark,

2007 to 2009

SrSCD in non-competitive athletes Age

grou

p

Age

at

deat

h

Gende

r

Sport Place Witnesse

d

HL

R

Prodromal

symptoms

Antecedent

symptoms

Autopsy Body

weigh

t

Heart

weigh

t

Body

mass

inde

x

≤35

years

12 Male

Running Public

Yes Yes None Angina ARVC* 110 422 36

14 Male

Football Publi

c

Yes Yes None None Con. Heart† 70 572 23

15 Male

Running Publi

c

Yes Yes Dizziness,

dyspnoea

Syncope,

presyncope SUDǁ 66 378 21

20 Female

Dancing Public

Yes Yes None Syncope VD¶ 50 360 19

30 Male

Running Publi

c

Yes Yes None None CAD† 158 730 40

34 Male

Running Publi

c

Yes Yes None Syncope ARVC N/A‡‡ 520 N/A‡

‡

>35

years

36 Male

Running Publi

c

Yes Yes Unspecific Angina,

dyspnoea

ARVC* 75 410 23

36 Male Cycling Home No No None None CAD† 110 522 31 36

Male Running Publi

c

No Yes None None Myocarditi

s

114 412 32

36 Male

Running Public

No Yes None Angina, dyspnoea

ARVC 89 526 24

37 Male Running Home Yes Yes Unspecific None CAD† 80 450 25

38 Male

Running Public

Yes Yes None None NcHH 82 364 25

39 Male

Running Publi

c

No No None None N/A‡‡ N/A‡‡ N/A‡‡ N/A‡

‡ 39

Male Running Publi

c

Yes Yes Dyspnoea Palpitations N/A‡‡ N/A‡‡ N/A‡‡ N/A‡

‡

40 Male

Running Public

Yes Yes None Presyncope, angina,

dyspnoea

MCD# 103 510 29

42 Male

Running Public

Yes Yes Angina None HCM** 110 712 33

42 Male

Cycling Publi

c

Yes Yes Angina None Myocarditi

s

89 486 29

42 Female

N/A Publi

c

Yes Yes None None SUDǁ 81 340 26

42 Male Cycling Home No Yes Angina

Angina, palpitations

, and

presyncope (in pain)

CAD† 102 561 31

42

Male

Gymnastic

s

Home N/A Yes Dyspnoea,

Palpitations

None HH†† 71 468 23

43 Male

Running Public

Yes Yes Unspecific Dyspnoea HH†† 118 588 32

43 Male Cycling Publi

c No Yes None

Syncope,

angina, dyspnoea

treated as

asthma

CAD† 86 581 28

43 Male

Cycling Publi

c

Yes Yes Unspecific Angina N/A‡‡ N/A‡‡ N/A‡‡ N/A‡

‡

44 Female

Cycling Public

No No None Dyspnoea, unspecific

N/A‡‡ N/A‡‡ N/A‡‡ N/A‡

‡

44 Male Stepping Home No No None None CAD† 76 430 24

44 Male

Cycling Home Yes Yes Presyncope Angina N/A‡‡ N/A‡‡ N/A‡‡ N/A‡

‡

45 Male

Ice skating Publi

c

Yes Yes None Angina N/A‡‡ N/A‡‡ N/A‡‡ N/A‡

‡

21

46 Male

Cycling Publi

c

Yes Yes Fatigue None CAD† 130 496 37

47 Male

Swimming Publi

c

Yes Yes Dizziness,

angina

Dizziness N/A‡‡ N/A‡‡ N/A‡‡ N/A‡

‡

47 Male

Running Public

Yes Yes None Angina CAD† N/A‡‡ 439 N/A‡

‡

49 Male

Cycling Publi

c

Yes Yes None Dyspnoea CAD† 96 564 28

49 Male

Cycling Publi

c

Yes Yes Unspecific None CAD† 90 516 30

49 Male

Cycling Public

Yes Yes None None N/A‡‡ N/A‡‡ N/A‡‡ N/A‡

‡

*ARVC; arrhythmogenic right ventricular cardiomyopathy, †CAD; coronary artery disease;

‡Con. Heart; congenital heart disease, ǁSUD; sudden unexplained death,

¶VD; valve disease, #MCD;

malformation of coronary vessel, **HCM; hypertrophic cardiomyopathy, ††HH; hypertrophic

heart, ‡‡N/A; not available, ǁ ǁNcHH; Non-concentric hypertrophic heart.

22

Table 3: Characterisation of sports-related sudden deaths in competitive athletes by age in Denmark, 2007 to

2009

SrSCD in competitive athletes Age

group Age

at

death

Gender Sport Place Witnessed HLR Prodromal

symptoms

Antecedent

symptoms

Autopsy Body

weight

Heart

Weight

Body

mass

index

≤35

years

13 Male Running Public Yes Yes None None ARVC* 54 248 19

20 Male Football Arena Yes Yes None None SUD‡ 74 384 21

31 Male Squash Home No Yes Presyncope, palpitations

Syncope SUD‡ N/A¶ 522 N/A¶

>35

years

37 Male Handball Arena Yes Yes Unspecific None CAD† 92 474 29 38 Male Cycling Public Yes Yes None None CAD† 85 568 24

40 Male Football Home Yes Yes Angina Unspecific CAD† 73 367 24

41 Male Handball Arena Yes Yes Angina None CAD† N/A¶ 428 N/A¶ 44 Male Cycling Public Yes Yes None None HHǁ 91 587 25

45 Male Football Arena Yes Yes Unspecific None N/A¶ N/A¶ N/A¶ N/A¶

47 Male Running Public No Yes None None CAD† 82 450 25

48 Male Football Arena Yes Yes None Angina HHǁ N/A¶ 560 N/A¶

*ARVC; arrhythmogenic right ventricular cardiomyopathy, †CAD; coronary artery

disease; ‡SUD; sudden unexplained death, ǁHH; Hypertrophic heart,

¶N/A; not

available