source: https://doi.org/10.7892/boris.13531 | downloaded: 9.8.2022
A pilot case–control study of behavioral aspects and risk
factors in Swiss climbers
Rebecca M. Hasler
a
, Priska Bach
a
, Monika Brodmann
a
, Dominik Heim
b
,
Jonathan Spycher
c
, Andreas Schotzau
d
, Dimitrios S. Evangelopoulos
a
,
Heinz Zimmermann
a
and Aristomenis K. Exadaktylos
a
Background Climbing is a popular sport in Switzerland,
with approximately 100 000 active participants. There is an
inherent risk of falls, overuse and stress-related trauma,
with a reported injury rate of 4.2 injuries per 1 000
climbing hours.
Objective Comparison of possible risk factors in patients
and noninjured controls.
Methods A case–control survey was conducted. Climbers
admitted to three trauma units between June and October
2008 were surveyed using a questionnaire evaluating nine
potential risk factors. The same questionnaire was
distributed to noninjured climbers during the same time
period. Logistic regression was performed.
Results Fifty patients and 63 controls were included in this
survey. Variables significant for patients were: more than
10 years versus less than 1 year of climbing experience
(odds ratio: 5.34; confidence interval: 1.16–17.76; P = 0.006)
and no previous experiences of the climbing route (odds
ratio: 2.72; confidence interval: 1.15–6.39; P = 0.022). No
statistical significance was detected for age, sex, difficulty
level of the climbing route, warm-up, readiness for risk and
abstinence from alcohol and drugs.
Conclusion Climbers with higher experience seem to be
more prone to injuries. Larger studies on this subgroup are
warranted, to identify typical risk profiles and to develop
preventive strategies. Furthermore, climbers should be
advised about the increased injury risk when trying
new climbing routes and specific information
should be given. European Journal of Emergency Medicine
19:73–76
c
2012 Wolters Kluwer Health | Lippincott
Williams & Wilkins.
European Journal of Emergency Medicine 2012, 19:73–76
Keywords: climbing, injury, risk factors
a
Department of Emergency Medicine, University of Bern, Inselspital, Bern,
b
Department of Surgery, Spital Frutigen, Frutigen,
c
Department of Orthopedic
Surgery, Spital Interlaken, Interlaken and
d
Scho
¨
tzau und Simmen, Statistical
Consulting, Basel, Switzerland
Correspondence to Dr Aristomenis K. Exadaktylos, MD, PD, FMH Anaesth DipTM
FCEM, Division of Anaest hesia, Department of Emergency Medicine, Director
Research and Clinical Development, Intensive Care and Emergency Medicine,
Inselspital Bern, University Hospital, Bern 3008, Switzerland
Tel: + 41796322900; fax: + 0041 31 632 4867;
e-mail: aristom enis@exadaktylos.ch
Received 29 November 2010 Accepted 11 May 2011
Introduction
What started as a traditional form of adventure has
nowadays grown into a popular recreational and compe-
titive activity, spreading rapidly across the globe. It has
been estimated that in the USA, more than 300 000
people have climbed a rock wall (http://www.hughston.com/
hha/a.climb.htm). The number of cli mbers, in general, is
estimated to be much higher, given the size of the US
country and opportunities for climbing there. In Switzer-
land, approximately 100 000 people regularly climb as a
recreational sport (unpublished data, Swiss Alpine
Club, 2010).
Climbing is a physically demanding sport, which allows
only slight errors, with a reported injury rate of 4.2
injuries per 1000 climbing hours [1]. As a result, there has
been a move to bring more awareness of the risks involved
to beginners, novices, and expert climbers, in the hope of
preventing injuries [2].
Climbing accounts only for one death in 320 000 climbs,
compared with scuba diving with one death in 200 000
dives or hang-gliding with one fatal injury in 116 000
flights (http://www.hse.gov.uk/education/statistics.htm). There-
fore, compared with other recreational activities, climbing
sports have a lower injury incidence and severity score
than many popular sports, including basketball, sail ing, or
soccer [3]. However, these numbers originate from the
UK and Germany, which have a different climbing
environment than Switzerland.
The increasing public interest in climbing injuries over
the last years prompted our institution to evaluate ways
of achieving more effective prevention by evaluating
potential risk factors. To the best of our knowledge, our
case–control survey of acute climbing injuries is the first
study of its kind in sports medicine literature.
Methods
Setting
Three emergency departments (EDs), one level I trauma
centre and two regional hospitals.
Original article 73
0969-9546
c
2012 Wolters Kluwer Health | Lippincott Williams & Wilkins DOI: 10.1097/MEJ.0b013e328348b460
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Case–control survey
All patients acutely injured from indoor or outdoor
climbing and admitted to one of the three EDs betwe en
1 June and 31 October 2008 were included. Patients with
chronic overuse syndromes, intracranial bleeding, skull
fractures, Glasgow Coma Score (GCS) of greater than 14
or persistent retrograde amnesia were excluded. Patients
with concussion were included as long as their GCS was
15 and they were able to fully and coherently understand
and answer the questions. No patients were interviewed
twice or in the role as a control and patient.
Patients reporting climbing injuries or being admitted as
climbing injuries by Emergency Medical Services were
interviewed by final year medical students, working in
the ED as a part of their training. Patients were
interviewed after the injury at one of the three EDs, or,
in cases that did not allow time for interview in the ED,
during their hospital stay. A questionnaire incorporating
nine potential risk factors was used. Noninjured climbers
(controls) were prospectively interviewed during the
same time period at different popular climbing spots,
using the same questionnair e.
We defined nine primary outcome measures as possible
risk markers, as they have been used in previous risk
assessment studies [4]. The variables included patient/
control characteristics (age, sex, and experience in
climbing), behavioral aspects [readiness for risk (the
readiness to take risks, which might be beyond ones’
abilities to cope with), abstinence from alcohol or drugs
while climbin g, the duration of warm-up, knowledge of
climbing route] and external conditions (level of climbing
route; Fig. 1).
Ethical considerations
Participation in the study was voluntary and anonymous;
confidentiality was granted. Data were collected, stored,
analyzed and shared according to the ethical committee
standards of the three hospitals.
Statistical analysis
To identify study groups based on various predictors,
univariate logistic regression analysis was performed.
Odds ratios (OR) with corresponding 95% confidence
intervals (95% CI) were reported. For ordinal or metric
variables, ORs were expressed as the ratio of the odds
increasing the predictor one unit. A P value of less than
0.05 was considered as significant.
All evaluations were calculated with R version 2.7.0 [5].
Results
Study population
Fifty patients and 63 controls were interviewed. Seventy-six
percent (n = 38) of patients and 67% (n = 42) of controls
were male. The mean age was 34.2 years (range, 16–64
years) for patients and 31.3 years (range, 16–55 years) for
controls. The median injury severity score was 8 (range,
1–48). Thirty-eight patients (76.0%) and 26 controls
(41.2%) performed outdoor climbing and 12 patients
(24.0%) and 37 controls (58.8%) performed indoor climbing.
Most injuries affected the limbs, followed by head and face
injuries and spinal trauma. Details are described in Fig. 2.
Logistic regression analysis shown in Table 1 demon-
strated that the following variables were significant for
patients: more than 10 years of climbing experience
(vs. < 1 year of climbing experience), and no previous
experiences of the climbing route. No statistical sig-
nificance was detected for age, sex, level of difficulty of
the climbing route, duration of warm-up, readiness for
risk and abstinence from alcohol and drugs. Crude
numbers of risk factor variables are described in Table 2.
Discussion
Reports on risk factors in climbing are rare and to the best
of our knowledge, there have been no case–control
studies on risk factors in climbing injuries, other than
Fig. 1
Nine primary outcome measures:
Climber characteristics
(1) Age years
(a) 16 –30
(b) 31 – 45
(c) 46 – 59
(d) > 59
(2) Sex: male/female
(3) Years of experience in climbing:
(a) <1
(b) 1–10
(c) >10
Behavioural aspects
(4) Readiness for risk: VAS 1–10 (1 implying minimal risk and 10 maximum of risk)
(a) 1 – 3
(b) 4 – 6
(c) 7 – 10
(5) Abstinence from alcohol while climbing: yes/no
(6) Abstinence from drugs while climbing: yes/no
(7) Duration of warm-up:
(a) none
(b) 1−10 min
(c) > 10 min
(8) Knowledge of climbing route:
(a) First ascent
(b) The route has already been taken two or more times in the past
External conditions
(9) Level of climbing route:
(a) ≤ 5b/VI-
(b) 5c – 6a/VI—VII
(d) ≥ 6b/VII
Possible risk factors. VAS, Visual Analogue Scale.
74 European Journal of Emergency Medicine 2012, Vol 19 No 2
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
overuse syndromes [1,6,7]. We showed that a higher level
of experience in climbing seems to be a risk factor for
being injured. We observed the highest injury rate for
climbers with more than 10 years of climbing experience.
One explanation for this could be that dedicated climbers
participate in different forms of climbing more often and
therefore increase their cumulative injury ris k [2]. A
further explanation could be that more experienced
climbers are used to manage dangerous situations easily
and therefore underestimate the still inherent risk. Last
but not least, more experienced climbers might suffer
from more chronic overuse injuries and therefore also be
more prone to acute injuries. It has also to be taken into
account that patients with severe and fatal injuries have
been excluded. We do not know whether these seriousl y
injured patients were predominantly novice or very
experienced climbers.
The lower interval of the variable ‘experience in climbing’
was intentionally as chosen as less than two times
climbing a route, as the investigators believe that
climbers climbing a route once only shoul d not be
classified as experienced.
We found no previous studies analysing the association of
experience with the climbing route and injuries. This
might be a risk factor, which has been previously
overlooked. Age and sex showed no statistical significance
between patients and controls and this finding is
supported by a study on climbers in the UK [7].
The term ‘readiness for risk’ means the attit ude to take
risks, which might be beyond ones abilities to cope with.
Therefore, climbers with smaller or greater climbing
experience will rate their risk with respect to their
personal abilities. The Visual Analogue Scale (VAS) is a
widely used tool to rate emotions and feelings in clinical
medicine and provide a good basis for assessments in this
study. Readiness for risk seems not to correlate with
injuries. However, after sustaining an accident, the
reported readiness to take risk might be overestimated
or underestimated. In contrast to other researchers who
concluded that climbers under alcohol and drug influence
account for more injuries, we could not find an association
between reported alcohol and drug consumption and
accidents [8].
Table 1 Univariate logistic regression analysis
Variable OR 95% CI
P
value
Age 1.01 0.98–1.05 0.23
Sex 1.42 0.63–3.23 0.42
Readiness for risk 0.44 0.15–1.30 0.32
Abstinence from alcohol 0.42 0.04–4.13 0.63
Abstinence from drugs 0.85 0.14–5.30 1.00
Duration of warm-up (5–10 min vs. no warm-up) 1.06 0.44–2.33 0.902
Duration of warm-up ( > 10 min vs. no warm-up) 0.98 0.31–3.11 0.966
Level of climbing route (5c-6a/VI–VII vs. < 5b/VI-) 0.81 0.31–2.14 0.675
Level of climbing route ( > 6b/VII vs. < 5b/VI-) 0.94 0.38–2.31 0.893
Experience with climbing route (route taken for the
first time vs. route taken for > 2 times in the past)
2.72 1.15–6.39 0.022
Climbing experience (1–10 years vs. < 1 year
climbing experience)
2.23 0.71–6.97 0.167
Climbing experience ( > 10 years vs. < 1 year
climbing experience)
5.34 1.61–17.76 0.006
CI, confidence interval; OR, odds ratio.
Table 2 Crude numbers of risk factors in patients and controls
Variable
Number of
patients Missing
Number of
controls Missing
Age (16–30; 31–45; 46–59;
> 59 years)
24;20;4;2 0 35;19;9;0 0
Gender (ma le:female) 37;13 0 42;21 0
Readiness for risk (1–3; 4–6;
7–10 VAS)
13;19;9 9 14;27;22 0
Abstinence from alcohol 48 1 60 0
Abstinence from drugs 47 1 60 0
Duration of warm-up (none;
< 10 min; > 10 min)
30;13;6 1 39;16;8 0
Level of climbing route (r 5b/V-;
5c–6a/VI–VII; Z 6b/VII)
16;13;19 2 19;19;24 1
Experience with climbing route
(climbed route < 2 ; Z 2 )
29;18 3 29;34 0
Climbing experience
(1;1–10; Z 10 years)
5;21;22 2 17;32;14 0
VAS, Visual Analogue Scale.
Fig. 2
ChestHead/face Abdomen Pelvis
Injured body region
Injury pattern
Spine Upper
extremities
Lower
extremities
100
80
60
40
20
0
Percentage
Climbers’ injury pattern.
Risk factors in climbers Hasler et al. 75
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Warm-up before climbing did not emerge as a protective
factor in our analysis. Of course, this result does not imply
that the warm-up should be omitted, as this study did not
link the performance of warm-up with specific types of
injuries.
Climbers attempting routes with increasing levels of
difficulty are said to be more prone to acute injuries and
overuse syndromes [7,9,10]. However, we found no
association between injuries and the level of difficulty
of the climbing route, which seems to be a key result of
our study.
Limitations
To minimize sources of bias, patients with severe head or
life-threatening injuries were excluded. Especially, as the
rehabilitation process of these patients and their ability to
answer a questionnaire varies widely, we decided to
exclude these patients. The generalization of the study
results is, therefore, limited by the examined patient
population. The results that emerged as statistically
significant did so only when seen as isolated factors and
not in the context of the distribution of all other factors in
the patient and control groups. Our study is limited in
numbers of participants and represents a pilot project for
understanding risk factors in cli mbing. Further investiga-
tions, including adjustm ent for suspected risk factors in
multiple regression analysis, are needed to substantiate
our results.
The numbers of outdoor and indoor climbers in the
patient and control group were not equal. However, only
risk factors affecting climbers in general and not
particularly due to specific types of climbing were asked
to minimize this source of bias. Although, patients with
moderate-to-severe brain injury were excluded, 18
patients suffered from mild head trauma or injury to
the face. Patients suffering from concussion were only
interviewed if their GCS was 15, and they were able to
answer the questions fully and coherently. Nevertheless,
this subpopulation might be more influenced from recall
bias than the rest of the study population. Questions on
alcohol and drug consumption were answered by self-
estimation and not on the observers own judgement and
therefore might lead to reporting bias. The question on
readiness for risk has been answered by self-estimation,
which can cause recall and information bias. After an
injury, patients may overestimate or underestimate their
readiness for risk. The VAS for the readiness for risk has
not been validated, and this may limit its value. In
general, VAS investigations have been validated for
emotions and ‘feelings’ in the past and the readiness to
take risk is certainly classified among feelings [11]. Falls
are regarded as ‘normal’ events during climbing, and
therefore climbing training often focuses on the techni-
que of falling and preventing injuries. What plays a major
role in these falls is the competence of the rope partner
to hold the falling climber. The questionnaire in this
study did not address these aspects, but focused on the
individual climber that suffered from an accident.
Conclusion
Climbers with higher experience seem to be more prone
to injuries and therefore larger studies on this subgroup
are warranted to show typical risk profiles and to develop
preventive strategies. Not the level of difficulty of the
route, but missing route experience seems to put
climbers at risk. Hence, advice about the increased inju ry
risk when trying new climbing routes and specific
information about the route should be given in advance.
In addition, physical, mental and technical preparat ions
of climbers, as well as the role of the rope par tner need
further investigation.
Acknowledgements
The authors thank Kathrin Dopke, MPH, study coordi-
nator, from the Department of Emergency Medicine,
Inselspital, University Hospital Bern, Switzerland, and
Mr Rodney Yeates, PhD, for English proofreading.
Conflicts of interest
The authors state that they have not received any
funding and they have no conflicts of interest, including
financial, consultant, institutional and other relationships
that might lead to bias or a conflict of the published work.
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