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ORIGINAL ARTICLE
Low-energy distal radius fractures in middle-aged
and elderly women—seasonal variations, prevalence
of osteoporosis, and associates with fractures
J. Øyen &G. E. Rohde &M. Hochberg &V. Johnsen &
G. Haugeberg
Received: 20 June 2009 /Accepted: 31 August 2009 /Published online: 23 September 2009
#International Osteoporosis Foundation and National Osteoporosis Foundation 2009
Abstract
Summary There is a lack of data on the prevalence of
osteoporosis in patients with distal radius fractures occurring
at the various seasons. The prevalence of osteoporosis is high,
both in patients with indoor and outdoor fractures and higher
than in controls. All female distal radius fracture patients
≥50 years should be referred for osteoporosis assessment.
Introduction The objectives of this study in female distal
radius fracture patients were to investigate seasonal differ-
ences, estimate the prevalence of osteoporosis, and identify
factors associated with distal radius fractures compared with
controls.
Methods In a 2-year period, 263 women ≥50 years suffered a
low-energy distal radius fracture in the geographic catchment
area. The 214 women who met for osteoporosis assessment
were age-matched with 191 controls. Bone mineral density
was assessed by dual energy X-ray absorptiometry at femoral
neck, total hip, and lumbar spine. Demographic and clinical
data were collected.
Results The prevalence of indoor fractures showed no
seasonal variance. For outdoor fractures, the prevalence
was highest in the winter months. The prevalence of
osteoporosis among patients with indoor fractures was
higher (58.5%) than outdoor fractures without (38.6%)
and with snow/ice (36.0%; p<0.001). The prevalence of
osteoporosis was higher in fracture patients (42.5%) than
controls (24.1%; p<0.001), this was also found in the
youngest age group 50–59 years (22.2% vs 1.8%; p<
0.001). In conditional logistic regression analyses osteopo-
rosis, current use of glucocorticoids, and living alone were
independently associated with distal radius fractures.
Conclusions Our study highlights that environmental factor,
as well as osteoporosis are associated with distal radius
fractures in middle-aged and elderly women. Osteoporosis is
also frequently found in outdoor patients, thus, all female
distal radius fracture patients ≥50 years should be referred for
osteoporosis assessment.
Keywords Bone mineral density .Distal radius fractures .
Osteoporosis .Risk factors .Seasonal variations
Introduction
Distal radius is one of the most frequent sites of low-
energy fracture in middle-aged and elderly women. A high
percentage of women with low-energy distal radius
fractures have osteoporosis [1] and bone mineral density
(BMD) has been found to be lower in distal radius fractures
patients compared to age-matched controls and bone density
reference populations [2,3].
J. Øyen
Department of Surgical Sciences,
Faculty of Medicine and Dentistry, University of Bergen,
Bergen, Norway
G. E. Rohde :V. Johnsen :G. Haugeberg (*)
Department of Rheumatology, Sørlandet Hospital,
Kristiansand, Service box 416, 4604 Kristiansand, Norway
e-mail: glenn.haugeberg@sshf.no
M. Hochberg
Departments of Medicine and Epidemiology and Preventive
Medicine, University of Maryland School of Medicine,
Baltimore, Maryland, USA
G. Haugeberg
Department of Neuroscience, Division of Rheumatology,
Norwegian University of Science and Technology,
Trondheim, Norway
Osteoporos Int (2010) 21:1247–1255
DOI 10.1007/s00198-009-1065-0
Environmental conditions may contribute to an increased
risk of distal radius fractures in elderly women, which has
been shown to occur more frequent in the winter months
[4–10], especially, on snowy and icy condition [10,11]. In
none of these studies, however, were the patients assessed
with bone density. Thus, there is a lack of data on the
prevalence of osteoporosis in patients with low-energy
distal radius fractures occurring at the various seasons.
Several risk factors have been identified to be associated
with low-energy distal radius fractures in women [9,12–22].
This includes low BMD [17,21], a history of falls [13,18,
21,22], a history of low-energy fractures [14,18,21], poor
cognitive status [17,21], frequent walking [16,17,20], icy
and snowy conditions [9], use of glucocorticoids (GCs) [23],
and a family history of fracture [19]. Current use of
oestrogen [12,17,19,21], an inactive lifestyle [15–17],
and high body mass index (BMI) [15,17] seems to have a
protective effect.
Our aims in the present study of a population-based
cohort of female low-energy distal radius fracture patients
were: (1) to explore for seasonal differences among the
distal radius fracture patients; (2) to estimate prevalence of
osteoporosis in distal radius fracture patients compared with
controls; and (3) to identify factors associated with distal
radius fractures.
Methods
Study design and study population
Participants in this comparative cross-sectional study
included middle-aged and elderly women with low-energy
distal radius fractures, and sex- and age-matched control
subjects randomly selected from the general population in
the same catchment area. Patients were recruited prospec-
tively; however, data for some of the variables listed in
Tab le 2were retrospectively collected, i.e., previous
fractures, history of fractures in parent, and menopause
status.
All patients were recruited from the same regional
hospital, Sørlandet Hospital in Kristiansand, located in
southern Norway, which is the only referral centre for
orthopaedic trauma in the region. The hospital osteoporosis
centre is organised according to the fracture liaison model
[1,24]. All patients aged 50 years and older who suffered a
low-energy distal radius fracture in the 2-year study period
of 2004 and 2005 were identified and according to routine
procedure, were invited for osteoporosis assessment and
fracture risk assessment at the osteoporosis centre. Patients
with obvious confusion or dementia or serious infections
were not invited for osteoporosis assessment. We also
excluded tourists from the study. At the osteoporosis centre,
as part of the clinical routine, clinical data were collected
for fracture risk assessment, and BMD was measured.
A low-energy fracture was defined as a minimal trauma
falling from standing height or less [25]. Patients with high-
trauma fractures were excluded. All diagnosed distal radius
fractures were based on X-rays examined by a radiologist.
A distal radius fracture was diagnosed according to
standard procedures and defined as located within 3 cm of
the radio-carpal joint [26]. At inclusion, the diagnoses were
confirmed by descriptions of the X-ray reports and by
medical notes from the orthopaedic surgeon. Patients with a
concomitant fracture of the ulna were also included.
The control subjects were randomly selected from the
Norwegian Population Registry. They were selected from
the general population in the same geographic area as the
patients and matched for sex and age. They were invited by
mail to participate in the study. We aimed to include one
control person for each patient. For patients aged 75 years
and older, we were unable to find age- and sex-matched
control subjects despite of several attempts. The study was
approved by the National Data Inspectorate and the
regional committees for medical research ethics.
Demographic and clinical data
Data on weight and height were collected and BMI
calculated. Height and weight were, in the majority of the
patients and controls, assessed at the osteoporosis centre;
however, in some few cases, self-reported values of patients
and controls who recently had their height and weight
measured were recorded in the database. A patient
questionnaire provided information regarding education,
marital status, previous and current smoking, previous and
current exercise, medical history, use of GCs, intake of
vitamin D and calcium, and use of post-menopausal
oestrogen therapy, bisfosfonate and selective oestrogen
receptor modulators (SERMs), age at menopause, previous
fracture, and history of hip fracture in parents and falls
(Table 2).
Inflammatory disease comprised inflammatory bowel
disease, rheumatoid arthritis (RA), ankylosing spondylitis,
psoriatic arthritis, and collagen vascular diseases. Endocrine
diseases included hyperparathyroidism, hypothyroidism,
and hyperthyroidism. Cardiovascular disease comprised
angina pectoris and cardiac infarction. Height change was
calculated as the difference between examined height and
the given maximum adult height and dichotomized at 3 cm.
Menopause before the age of 45 years was defined as early.
A previous fracture was defined as a fracture of the distal
radius, upper arm, rib, spine, hip, femur, or lower leg from
low-energy trauma (fall from standing height or less) after
the age of 50 years. To assess heredity, we asked for
mother’s and father’s history of hip fracture after the age of
1248 Osteoporos Int (2010) 21:1247–1255
50 years. Previous and current exercise was categorised as
activity for minimum 1.5 h/week or no exercising.
BMD measurements and reference population
Bone mineral density was measured at femoral neck,
total hip, and lumbar spine (L2–L4)byfourtrained
nurses using the same dual energy X-ray absorptiometry
(DXA) equipment (General Electric, Lunar Prodigy). The
machine was calibrated every day, and the machine was
stable over the entire measurement period. The in-vitro
long-term coefficient of variance (CV) for the spine
phantom was 0.62% for the entire study period. The in-
vivo CV for the measurement procedure was 1.68% for
right femoral neck and 1.56% for left femoral neck,
0.94% for the right total hip, 0.88% for the left total hip,
and 1.26% for L2–L4. We used the BMD values for the
left hip, unless, there was a history of previous fracture
or surgery. Scans from the right hip were used in 14
(6.5%) patients and five (2.6%) controls. Due to bilateral
fracture or surgery in four controls, only spine scans
were used. In one (0.5%) patient and one control (0.5%),
spine scans could not be analysed.
Bone mineral density was categorised according to the
World Health Oranization definition of osteoporosis (T-score
≤−2.5 standard deviation (SD), osteopenia (>−2.5 and <−1.0
SD), and normal bone density (≥−1.0 SD). A patient was
categorised to have normal bone density if T-score at all
measurement sites (femoral neck, total hip, and L2–L4) was
≥−1.0 SD. If T-score was lower than −1.0 SD but higher than
>−2.5 SD at any of the measurement sites, the patient was
categorised as osteopenia. A patient was categorised as
osteoporosis if T-score was ≤−2.5 SD at any of the
measurement sites.
The T-score and the Z-score calculations were derived
from a combined European/US reference population sup-
plied by the DXA manufacturer Lunar [27].
Statistical analysis
Categorical variables were expressed as numbers and percen-
tages and continuous variables as means with variance
expressed as SD or range. We used independent-samples t
test for continuous variables and chi-square test (Fisher’s
exact test) for categorical variables in comparisons between
fracture patients and controls and between distal radius
fracture patients attending DXA and not attending DXA.
Chi-square test was used to estimate the prevalence of
patients with distal radius fractures due to osteoporosis,
osteopenia, and normal BMD in spring, summer, autumn,
and winter and due to indoor fractures, outdoor fractures on
snow/ice, and not on snow/ice. ANOVA post hoc tests for
multiple comparisons with Bonferroni correction were used
to compare age and BMI in fracture patients due to seasons,
indoor fractures, and outdoor fractures on snow/ice, and not
on snow/ice. Assuming a normal distribution, the risk is 68%
of being within ± 1 SD of the mean, thus, the expected
proportion of Z-scores ≤−1.0 SD is 16% by default. The
95% confidence interval (CI) range for proportions of
patients having a Z-score of ≤−1.0 SD was calculated using
the equation for binomial distribution [28]. The association
between low-energy distal radius fractures as dependent
variable and the demographic and clinical variables included
in Table 2and osteoporosis as independent variables were
tested both in unadjusted and in adjusted conditional logistic
regression analyses. The degree of association was expressed
as odds ratio (OR) with 95% CI. In the adjusted analyses, all
variables in the unadjusted analysis with a pvalue≤0.10
were tested. A two-tailed pvalue<0.05 was considered
statistically significant. All analyses were performed using
SPSS software for Windows, version 15.0 (SPSS Inc.,
Chicago, Illinois, USA).
Results
In the two-year period, 274 female low-energy distal radius
fracture patients were assessed and treated at the hospital.
Among them were 11 tourists who were excluded from the
present analysis as the scope of this study was resident women
in the geographic area of the hospital. Among the 263 resident
distal radius fracture patients, 17 were excluded due to
dementia or confusion and 14 were excluded due to other
reasons. Further, 18 patients were unwilling to be assessed at
the osteoporosis centre. The final study sample comprised 214
patients, giving a response rate among potentially eligible
resident patients of 81.4%. For the age groups of 50–59 years,
60–69 years, and for patients 70 years and above, the response
rate was 90.0%, 88.7%, and 73.5%, respectively. The mean
time between fractures and examination at the osteoporosis
centre was 14.4 days (range 1–109 days).
Mean age for all 263 patients were 70.1 years (SD 11.1).
Resident patients not assessed at the osteoporosis centre
(74.8 years, SD 12.4) were in mean 6.1 years older than
patients assessed at the osteoporosis centre (68.7 years,
SD 10.3; p<0.001).
Distal radius fracture prevalence and seasonal variations
The prevalence of distal radius fractures, which occurs indoor,
is stable at all seasons (Fig. 1). However, for outdoor
fractures, the prevalence varied across the seasons with the
lowest prevalence in the summer months and the highest in
the winter months. The distal radius fracture patients
assessed at the osteoporosis centre had lower prevalence of
indoor fractures compared with those not assessed at the
Osteoporos Int (2010) 21:1247–1255 1249
osteoporosis centre (Table 1). Patients with indoor fractures
were also significantly older (74.1 years; SD 11.1) than
patients with outdoor fracture both on ice (65.5 years; SD
9.0, p<0.001) and not on ice (68.9 years; SD 9.7, p=0.011).
There were no significant differences in BMI between the
patients with indoor fractures (25.7 kg/m
2
; SD 5.9) compared
to outdoor fractures on snow/ice (25.2 kg/m
2
;SD4.2)and
not on snow/ice (25.5 kg/m
2
; SD 3.9, p=1.000).
Distal radius fracture patients and age-matched controls
Demographic variables, clinical characteristics, and bone
density values for patients assessed at the osteoporosis
centre and controls are shown in Table 2. The patients with
distal radius fractures were not optimally matched for age
with controls as they were significant older. Patients also
had a lower weight than the control subjects. More patients
than controls were living alone, and the use of GCs was
higher among the patients. The patients had also higher
prevalence of secondary osteoporosis and lower BMD,
T-score, and Z-score than the controls at all measurements
sites. The same variables were significant when we adjusted
for age. For the other variables listed in Table 2,no
significant differences were seen between the two groups.
Prevalence of low BMD and osteoporosis
The distal radius fracture patients had a higher prevalence
of osteoporosis compared to the controls (42.5% vs 24.1%,
p<0.001; Fig. 2). Detailed BMD data in patients and
controls is shown in Table 2. The prevalence of osteopo-
rosis was significantly higher for the distal radius fracture
patients compared to the controls in the age groups
50–59 years (22.2% vs 1.8%, p<0.001) and 70 years and
older (59.8% vs 43.1%, p=0.043), but was not significant
in the age group 60–69 years (33.3% vs 22.2%, p=0.168).
The corresponding figures for osteopenia were 53.7% versus
54.5% (p=1.000) in the age group 50–59 years, 54.0 versus
48.4% (p=0.596) in the age group 60–69 years and 32.0%
versus 45.8% (p=0.078) in the group 70 years and older.
There were no significant differences in the proportion
of patients with distal radius fractures with osteoporosis,
osteopenia, and normal BMD in spring (37.1%, 43.5%, and
19.4%), summer (44.1%, 44.1%, and 11.8%), autumn
(48.0%, 42.0%, and 10.0%), and winter (43.5%, 44.9%,
and 11.6%).
In patients who were fractured outside the proportion of
patients with a reduced BMD adjusted for age (defined as
Z-score below −1 SD, expected to be 16% in the reference
population) was significantly higher in patients who
fractured on ice and snow, but not in patients who fractured
without ice and snow (Table 3).
Fig. 1 Number of female patients with distal radius fractures at the four
seasons which occurred indoor, outdoor, and outdoor on ice/snow in the
2-year period. The total in the figures differs from 263 due to missing data
on whether fracture occurred indoor or outdoor with or without ice/snow. In
15 patients, the case reports contained no information whether fracture had
occurred indoor or outdoor (spring—five patients, summer—two patients,
autumn—one patient, and winter—seven patients), and in three patients,
there were no data whether outdoor fracture had occurred on ice/snow or
not (spring—one patient, autumn—one patient, and winter—one patient)
Table 1 Fracture characteristics in resident female distal radius fracture patients assessed at the osteoporosis centre compared with patients not
assessed at the osteoporosis centre. Data are given as numbers and percentage
Distal radius patients attending DXA (n=214) Distal radius patients not attending DXA (n=49) pvalue
Fractures spring 61 (28.5) 10 (20.4) 0.288
Fractures summer 34 (15.9) 11 (22.2) 0.294
Fractures autumn 50 (23.4) 9 (18.4) 0.570
Fractures winter 69 (32.2) 19 (38.8) 0.404
Indoor fractures
a
53 (25.0) 20 (55.6) 0.001
Outdoor fractures, no snow/ice
a
70 (33.0) 7 (19.4) 0.121
Outdoor fractures on snow/ice
a
89 (42.0) 9 (25.0) 0.065
a
The total number for indoor outdoor ice Y/N varies from 214 due to missing data
1250 Osteoporos Int (2010) 21:1247–1255
Table 2 Demographic variables, clinical characteristics, and bone density measures in female distal radius fracture patients and controls. Mean
(SD) for continuous variables and numbers (%) for categorical variables
Patients (n=214) Controls (n=191) pvalue
Demographics
Age (years) 68.7 (10.3) 66.9 (8.8) 0.047
Body height (cm) 164.5 (6.2) 164.1 (6.3) 0.436
Body weight (kg) 68.8 (12.8) 71.4 (13.5) 0.047
BMI (kg/m
2
) 25.4 (4.6) 26.5 (4.4) 0.017
Education (>13 years) 33 (18.6) 49 (25.8) 0.105
Living alone 103 (49.8) 70 (36.8) 0.011
Smoking
Previous 59 (33.5) 56 (33.1) 1.000
Current 30 (14.3) 22 (11.6) 0.459
Exercise (≥1.5 h/week)
Previous 174 (84.1) 165 (86.8) 0.478
Current 142 (68.3) 141 (74.2) 0.223
Clinical characteristics
Rheumatoid arthritis 7 (3.3) 1 (0.5) 0.071
Endocrine diseases 18 (8.5) 22 (11.5) 0.321
Cardiovascular diseases 29 (13.6) 26 (13.6) 1.000
Diabetes
Type I 4 (1.9) 1 (0.5) 0.376
Type II 4 (1.9) 7 (3.7) 0.362
Glucocorticoids
Ever 22 (11.2) 9 (4.9) 0.025
Current 14 (7.1) 3 (1.6) 0.012
≥3 months 10 (4.7) 5 (2.6) 0.305
Secondary osteoporosis 37 (17.3) 19 (9.9) 0.043
Calcium supplement 38 (18.4) 28 (14.7) 0.348
Vitamin D supplement 94 (47.0) 82 (43.2) 0.478
Oestrogen 16 (7.5) 13 (6.8) 0.849
Bisfosfonate/SERM 16 (7.5) 10 (5.3) 0.420
Bisfosfonate/SERM/oestrogen/other 33 (15.4) 30 (15.7) 1.000
Loss of height (≥3 cm) 56 (30.4) 67 (35.8) 0.273
Post-menopausal 194 (96.0) 185 (97.4) 0.577
Menopause <45 years 27 (15.0) 17 (9.4) 0.147
Previous fracture 69 (33.3) 61 (33.2) 1.000
History of hip fracture in parent 18 (8.9) 20 (10.5) 0.612
Falls (≥1 fall last year) 85 (47.2) 62 (39.5) 0.186
BMD
BMD femoral neck (g/cm
2
) 0.78 (0.13) 0.84 (0.13) 0.000
BMD total hip (g/cm
2
) 0.82 (0.14) 0.89 (0.15) 0.000
BMD L2–L4 (g/cm
2
) 1.03 (0.19) 1.10 (0.18) 0.000
T-score femoral neck −2.11 (1.06) −1.62 (1.12) 0.000
T-score total hip −1.45 (1.03) −0.91 (1.18) 0.000
T-score L2–L4 −1.44 (1.60) −0.83 (1.49) 0.000
Z-score femoral neck −0.34 (0.87) 0.00 (0.94) 0.000
Z-score total hip −0.40 (0.89) 0.08 (1.03) 0.000
Z-score L2–L4 −0.07 (1.49) 0.39 (1.35) 0.002
Osteoporosis femoral neck 77 (37.4) 39 (20.9) 0.000
Osteoporosis total hip 41 (19.9) 21 (11.2) 0.019
Osteoporosis L2–L4 54 (25.1) 23 (12.1) 0.001
Z-score≤−1.0 SD femoral neck 52 (25.5) 23 (12.3) 0.001
Z-score≤−1.0 SD total hip 58 (28.2) 31 (16.6) 0.008
Z-score≤−1.0 SD L2-L4 56 (26.3) 34 (17.9) 0.055
SD standard deviation, BMI body mass index. SERM selective oestrogen receptor modulator, BMD bone mineral density
Osteoporos Int (2010) 21:1247–1255 1251
The prevalence of osteoporosis among patients with
indoor fractures was higher (58.5%) than outdoor fractures
without (38.6%; p<0.001) and with snow/ice (36.0%; p<
0.001). The prevalence of osteopenia among patients with
outdoor fractures with ice/snow (55.1%) and without ice/
snow (40.0%) was higher than indoor fractures (30.2%; p<
0.001 for both) (Fig. 2).
Risk of distal radius fractures
In unadjusted conditional logistic regression analyses, a
significant association with distal radius fractures for all
tested variables in Table 2was found for age (OR 1.02, 95%
CI 1.00–1.04; p=0.050), weight (OR 0.99, 0.97–1.00; p=
0.048), BMI (OR 0.95, 0.91–0.99; p=0.018), living alone
(OR 1.70, 1.14–2.54; p=0.010), ever use of GCs (OR 2.46,
1.10–5.49; p=0.028), current use of GCs (OR 4.64, 1.31–
16.42; p=0.017), and for osteoporosis (OR 2.33, 1.52–3.58;
p<0.001). Among the other tested independent variables,
only RA had a pvalue≤0.10 (OR 6.43, 0.78–52.7;
p=0.083). In adjusted conditional logistic regression analy-
ses, we tested variables with a pvalue≤0.10 in unadjusted
analysis.
We used BMI, and current use of GC in the model as
these variables were more strongly associated with distal
radius fracture than weight and ever use of GCs. The
variables with a pvalue≤0.10 tested in unadjusted analyses
for their association with low-energy distal radius fractures
included age, BMI, osteoporosis, current use of GC, living
alone, and RA. As RA had a widely CI, it was excluded from
the model. In this final model osteoporosis (OR 1.73, 1.05–
2.85; p=0.031), current use of GCs (OR 4.86, 1.33–17.74;
p=0.015), and living alone (OR 1.57, 1.00–2.47; p=0.049)
were independently associated with distal radius fractures
(Table 4).
Discussion
Our study highlights the seasonal variations in distal radius
fractures in middle-aged and elderly women. Further, our
data emphasise the importance of osteoporosis found in our
study to be a strong and consistent risk factor for distal
radius fractures in these women independent of age. In
addition to osteoporosis, living alone and current use of
GCs were found to be independently associated with low-
energy distal radius fractures. Surprisingly, high age, BMI,
previous low-energy fractures, and neither falls of the last
years known from the literature as risk factors for low-
energy fractures [13–15,17,18,21,22,29] were found to
be independently associated with low-energy distal radius
fractures.
Despite our attempt to perform a population-based study
on low-energy distal radius fractures in women aged
50 years and older, our case-control study has several
limitations. Some of the data for both patients and controls
Fig. 2 Percentage of female patients with osteoporosis, osteopenia,
and normal BMD in indoor, outdoor without ice/snow, and outdoor
with ice/snow fractures, and all distal radius fracture patients and
controls. Normal BMD if T-score was ≥−1.0 SD at all measurement
sites (femoral neck, total hip, and spine L2–L4). Osteopenia, if T-score
was lower than −1.0 SD but higher than >−2.5 SD at any of the three
measurement sites. Osteoporosis, if T-score was ≤−2.5 SD at one or
more of the three measurement sites
Table 3 Percentage of female distal radius fracture patients and subgroups of fracture patients according to indoor, outdoor on no ice and outdoor
on ice fractures and controls with Z-score≤−1.0 SD in femoral neck, total hip and L2-L4. Data are given as percentage and 95% confidence
intervals
All (n=214) Indoor (n=53) Outdoor, without ice
(n=70)
Outdoor, with ice
(n=88)
Controls
(n=191)
Z-score≤−1.0 SD femoral neck 25.2 (19.3–31.1) 34.7 (28.2–41.2) 14.9 (10.0–19.8) 27.3 (21.2–33.4) 12.3 (7.5–17.1)
Z-score≤−1.0 SD total hip 28.2 (22.0–34.4) 36.7 (30.1–43.3) 22.4 (16.7–39.1) 28.4 (22.2–34.6) 16.6 (11.2–22.0)
Z-score≤−1.0 SD L2–L4 26.3 (20.3–32.3) 26.4 (20.4–32.4) 20.0 (14.5–25.5) 31.8 (25.4–38.2) 17.9 (12.4–23.4)
Table 3 Percentage of female distal radius fracture patients and
subgroups of fracture patients according to indoor, outdoor on no ice
and outdoor on ice fractures and controls with Z-score≤−1.0 SD in
femoral neck, total hip and L2-L4. Data are given as percentage and
95% confidence intervals
1252 Osteoporos Int (2010) 21:1247–1255
were retrospectively collected. Retrospective data collection
can be biased by recall problems. In combination with a
cross-sectional study design, this may have influenced the
ability to identify potential risk factors for distal radius
fractures in our study. The densitometry reports were not
reviewed for severe spondylarthritis, thus, the prevalence
data on osteoporosis at spine, especially, in the highest age
groups is most likely underestimated. Despite the high
participant rate (81%), patients assessed at the osteoporosis
centre were in mean 6 years younger than patients who
were not assessed at the osteoporosis centre. This indicates
that older patients are less prone to respond to follow-up
examination at an osteoporosis centre. Thus, our data on
prevalence of osteoporosis in our female low-energy distal
radius fracture population are most likely underestimated as
discussed below.
However, the strength of the present study is that we
were able to identify all females aged 50 years and older
with a low-energy distal fracture in the hospital catchment
area in the 2-year study period. This was possible as
patients with a distal radius fracture in this area are only
diagnosed and treated at one orthopaedic trauma ward. A
further strength is that patients examined at the osteoporosis
centre were assessed in mean only 14 days after fracture
date. From the medical records in patients who were not
assessed at the osteoporosis centre, we were able to collect
data on age and fracture date and in the vast majority of
patients also, if the fracture had occurred indoor or outdoor
or if the patients fell on ice or snow. This allowed us on a
population basis to describe age and seasonal variation in
female distal radius fracture patients aged 50 years and
older.
The prevalence of distal radius fractures, which occurs
indoor, was stable at all seasons. However, for outdoor
fractures, the prevalence varied across the seasons with the
lowest prevalence in the summer months and the highest in
the winter months. These data support that snowy and icy
conditions contribute to an increased risk for low-energy
distal radius fractures, as also has been reported by others
[4,7–11]. Among the patients with indoor fracture, the
prevalence of osteoporosis (58.5%) was significantly higher
than in patients with outdoor fractures both on snow/ice
(36.0%) and without snow/ice (38.6%). This is most likely
explained by the higher age in patients with indoor fractures
than in patients with outdoor distal radius fractures, but
may also be explained by different fall mechanisms in the
three groups.
As discussed above, ice and snow increases the risk for
low-energy distal radius fractures in women. Surprisingly,
in patients who fractured outside the proportion of patients
with a reduced BMD adjusted for age (defined as Z-score
≤−1.0 SD, expected to be 16% in the reference population)
was significantly higher in patients who fractured on ice and
snow, but not in patients who fractured without ice and snow
(Table 3). One explanation may be that the trauma forces
involved in distal radius fractures in women, which occurs
outside without ice/snow are stronger than in patients with
trauma on ice/snow. We think that this finding is unexpected
as fractures on snow and ice are thought to be more related
to circumstances, related to the fall and increased trauma
forces, and not to the presence of reduced BMD.
The prevalence of osteoporosis was almost doubled in
the distal radius fracture patients (42.5%) compared to the
controls (24.1%). Our data are in accordance with the study
by McLellan et al. [1] who diagnosed osteoporosis in 41%
and normal BMD in 15% of 420 female wrist fracture
patients from Glasgow. Kanterewicz et al. [2] reported a
lower mean T-score in total hip and spine compared to the
control subjects. However, they found no significant
difference in mean Z-score at lumbar spine between
patients and controls as we did in the present study. We
also found a higher prevalence of osteoporosis in fracture
patients compared to controls in the youngest age group
50–59 years (22.2% vs 1.8%). This emphasise that
osteoporosis is also a strong risk factor for low-energy
distal radius fractures in middle-aged women and that it is
important to also assess this age group for osteoporosis.
In unadjusted analyses, our data revealed that age, BMI,
living alone, current use of GCs, RA, and osteoporosis
were found to be statistically significantly associated with
Table 4 Associates with low-energy distal radius fractures tested both in unadjusted and in adjusted conditional logistic regression models
Variables tested in unadjusted
models
Variables tested in an adjusted
model
OR (95% CI) pvalue OR (95% CI) pvalue
Age (years) 1.02 (1.00–1.04) 0.050 1.00 (0.97–1.02) 0.733
BMI (kg/m
2
) 0.95 (0.91–0.99) 0.018 0.97 (0.92–1.01) 0.151
Osteoporosis at femoral neck, total hip and/or L2–L4 (no/yes) 2.33 (1.52–3.58) 0.000 1.73 (1.05–2.85) 0.031
Living alone (no/yes) 1.70 (1.14–2.54) 0.010 1.57 (1.00–2.47) 0.049
Current use of GCs (no/yes) 4.64 (1.31–16.42) 0.017 4.86 (1.33–17.74) 0.015
BMI body mass index. GCs glucocorticosteroids
Osteoporos Int (2010) 21:1247–1255 1253
an increased risk of low-energy distal radius fractures.
However, when these variables were adjusted for each
other, osteoporosis remained consistently and independent-
ly associated with distal radius fractures. In the final model
without RA as the CI was wide, osteoporosis, living alone,
and current use of GC were independently associated with
distal radius fractures. Our results are in accordance with
previous studies, which also found low BMD [17,21]tobe
a strong predictor for distal radius fractures. In a 2-year
longitudinal study among 9,704 women older than 65 years,
171 patients had a distal radius fracture during follow-up
[17]. From this study, the authors concluded that low BMD
was the strongest risk factor for distal radius fracture and
that the fractures often occurred as a result of falling [17].
In our study, one or more falls during the last year was not a
significant risk factor of a distal radius fracture. Vogt et al.
[21] found low BMD, a history of recurrent falls, and a
previous low-energy fracture as the strongest risk factors
for distal radius fractures in 427 women aged 50 years and
older while current use of oestrogen had a protective effect.
In accordance with Korpelainen et al. [30], we found a
higher risk for fractures in elderly women living alone. This
is also supported by Faulkner et al. [31] who concluded that
strong social networks may protect against risk of falling. A
possible explanation of these findings may be that these
women living alone may have a different daily life pattern
and may be in poorer physical condition. However, we did
not find any association between fracture risk and falls or
physical activity in our study.
The GCs are widely used of treatment in many immune-
mediated inflammatory disorders [32]. However, use of GCs
is associated with side-effects, such as bone loss and
increased fracture risk [23,33,34]. Our results indicate a
relationship between current use of GCs and risk of distal
radius fractures and are in accordance with van Staa et al.
[23] who investigated 244,235 oral GCs users and 244,235
controls in a retrospective cohort study and found a relative
rate (RR) of forearm fractures during GCs treatment of 1.09
(95% CI, 1.01–1.17). However, in this study the risk was
greater for hip (RR 1.61, 1.47–1.76), vertebral (RR 2.60,
2.31–2.92), and non-vertebral fractures (RR 1.33, 1.29–1.38).
In the study by Steinbuch et al. [35], GC treated patients were
also found to have a significant increased risk of hip,
vertebral, and non-vertebral fractures, but no significant risk
was found for forearm fractures. One explanation of these
findings may be that the bone tissue in vertebrae and femoral
neck sites are composed primarily of trabecular bone, which
are more susceptible to the effects of oral GCs exposure than
the cancellous bone tissue in the forearm.
The lack of a strong association between age and low-
energy distal radius fracture in middle-aged and elderly
female patients may not be as surprising as it has been
shown that the incidence of distal radius fractures does not
increase dramatically with age as has been shown for hip
fractures [29]. However, we matched on age, and this may
be the explanation.
A history of previous low-energy fractures in middle-
aged and elderly patients has been identified to be a strong
risk factor for subsequent fractures [14,18,21]. In our
study, this was not found to be associated with distal radius
fracture. In both patients and controls, one third reported a
history of a previous low-energy fracture. One explanation
may be that individuals in the control group who previously
had a fracture were more willing to participate in a study,
which then would bias our results.
We conclude, from the present study that both environ-
mental factors, which increase the risk of falling (e.g., ice
and snow), as well as osteoporosis contributes to an
increased risk of distal radius fractures in middle-aged and
elderly women. Because the prevalence of osteoporosis is
high, both in patients with indoor and outdoor low-energy
distal radius fractures and osteoporosis is strongly and
independently associated with distal radius fractures; all
female patients aged 50 years and older should be referred
for osteoporosis assessment. Action programmes targeting
osteoporosis and environmental factors may, thus, reduce
the prevalence of distal radius fractures in middle-aged and
elderly women.
Acknowledgements We gratefully appreciate the expert technical
assistance and help with the data collection of the osteoporosis nurses
Lillann Krüger Hæstad, Hanne Vestaby, Tove Kjøstvedt, and Åse
Birkedal. This work has been supported and funded by the
Competence Development Fund of Southern Norway and Sørlandet
Hospital HF, Norway.
Conflicts of interest None.
References
1. McLellan AR, Gallacher SJ, Fraser M, McQuillian C (2003) The
fracture liaison service: success of a program for the evaluation
and management of patients with osteoporotic fracture. Osteoporos
Int 14:1028–1034
2. Kanterewicz E, Yanez A, Perez-Pons A, Codony I, Del Rio L,
Diez-Perez A (2002) Association between Colles’fracture and
low bone mass: age-based differences in postmenopausal women.
Osteoporos Int 13:824–828
3. Löfman O, Hallberg I, Berglund K, Wahlstrom O, Kartous L,
Rosenqvist AM, Larsson L, Toss G (2007) Women with low-
energy fracture should be investigated for osteoporosis. Acta
Orthop 78:813–821
4. Thompson PW, Taylor J, Dawson A (2004) The annual incidence
and seasonal variation of fractures of the distal radius in men and
women over 25 years in Dorset, UK. Injury 35:462–466
5. Falch JA (1983) Epidemiology of fractures of the distal forearm in
Oslo, Norway. Acta Orthop Scand 54:291–295
1254 Osteoporos Int (2010) 21:1247–1255
6. Solgaard S, Petersen VS (1985) Epidemiology of distal radius
fractures. Acta Orthop Scand 56:391–393
7. Bischoff-Ferrari HA, Orav JE, Barrett JA, Baron JA (2007) Effect
of seasonality and weather on fracture risk in individuals 65 years
and older. Osteoporos Int 18:1225–1233
8. Hemenway D, Colditz GA (1990) The effect of climate on
fractures and deaths due to falls among white women. Accid Anal
Prev 22:59–65
9. Jacobsen SJ, Sargent DJ, Atkinson EJ, O'Fallon WM, Melton LJ 3rd
(1999) Contribution of weather to the seasonality of distal forearm
fractures: a population-based study in Rochester, Minnesota.
Osteoporos Int 9:254–259
10. Hove LM, Fjeldsgaard K, Reitan R, Skjeie R, Sörensen FK (1995)
Fractures of the distal radius in a Norwegian city. Scand J Plast
Reconstr Surg Hand Surg 29:263–267
11. Lauritzen JB, Schwarz P, McNair P, Lund B, Transbol I (1993)
Radial and humeral fractures as predictors of subsequent hip,
radial or humeral fractures in women, and their seasonal variation.
Osteoporos Int 3:133–137
12. Cauley JA, Seeley DG, Ensrud K, Ettinger B, Black D,
Cummings SR (1995) Estrogen replacement therapy and fractures
in older women. Study of Osteoporotic Fractures Research Group.
Ann Intern Med 122:9–16
13. Hagino H, Fujiwara S, Nakashima E, Nanjo Y, Teshima R (2004)
Case-control study of risk factors for fractures of the distal radius
and proximal humerus among the Japanese population. Osteo-
poros Int 15:226–230
14. Holmberg AH, Johnell O, Nilsson PM, Nilsson J, Berglund G,
Akesson K (2006) Risk factors for fragility fracture in middle age.
A prospective population-based study of 33, 000 men and women.
Osteoporos Int 17:1065–1077
15. Honkanen RJ, Honkanen K, Kroger H, Alhava E, Tuppurainen M,
Saarikoski S (2000) Risk factors for perimenopausal distal
forearm fracture. Osteoporos Int 11:265–270
16. Ivers RQ, Cumming RG, Mitchell P, Peduto AJ (2002) Risk
factors for fractures of the wrist, shoulder, and ankle: the Blue
Mountains Eye Study. Osteoporos Int 13:513–518
17. Kelsey JL, Browner WS, Seeley DG, Nevitt MC, Cummings SR
(1992) Risk factors for fractures of the distal forearm and
proximal humerus. The Study of Osteoporotic Fractures Research
Group. Am J Epidemiol 135:477–489
18. Kelsey JL, Prill MM, Keegan TH, Tanner HE, Bernstein AL,
Quesenberry CP Jr, Sidney S (2005) Reducing the risk for distal
forearm fracture: preserve bone mass, slow down, and don’t fall!
Osteoporos Int 16:681–690
19. Mallmin H, Ljunghall S, Persson I, Bergstrom R (1994) Risk
factors for fractures of the distal forearm: a population-based case-
control study. Osteoporos Int 4:298–304
20. Silman AJ (2003) Risk factors for Colles’fracture in men and
women: results from the European Prospective Osteoporosis
Study. Osteoporos Int 14:213–218
21. Vogt MT, Cauley JA, Tomaino MM, Stone K, Williams JR, Herndon
JH (2002) Distal radius fractures in older women: a 10-year follow-
up study of descriptive characteristics and risk factors. The study of
osteoporotic fractures. J Am Geriatr Soc 50:97–103
22. Winner SJ, Morgan CA, Evans JG (1989) Perimenopausal risk of
falling and incidence of distal forearm fracture. BMJ 298:1486–
1488
23. Van Staa TP, Leufkens HG, Abenhaim L, Zhang B, Cooper C
(2000) Use of oral corticosteroids and risk of fractures. J Bone
Miner Res 15:993–1000
24. McLellan AFM (2001) Fractures in women over 50 years:
implications for the secondary prevention of osteoporotic fractures.
JBoneMinerRes16:290
25. Cooper C, Melton LJ 3rd (1996) Magnitude and impact of
osteoporosis and fractures. Academic Press, San Diego
26. Rockwood CA, Green DP, Bucholz RW (2006) Rockwood and
Green's fractures in adults. Lippincott William and Wilkins,
Philadelphia
27. Mazess RB, Barden H (1999) Bone density of the spine and femur
in adult white females. Calcif Tissue Int 65:91–99
28. Altman D (1999) Comparing groups: categorical data. Practical
statistics for medical research. Chapman and Hall/CRC, London
29. Cummings SR, Melton LJ (2002) Epidemiology and outcomes of
osteoporotic fractures. Lancet 359:1761–1767
30. Korpelainen R, Korpelainen J, Heikkinen J, Vaananen K,
Keinanen-Kiukaanniemi S (2006) Lifelong risk factors for
osteoporosis and fractures in elderly women with low body mass
index—a population-based study. Bone 39:385–391
31. Faulkner KA, Cauley JA, Zmuda JM, Griffin JM, Nevitt MC
(2003) Is social integration associated with the risk of falling in
older community-dwelling women? J Gerontol 58:954–959
32. Walsh LJ, Wong CA, Pringle M, Tattersfield AE (1996) Use of oral
corticosteroids in the community and the prevention of secondary
osteoporosis: a cross sectional study. BMJ 313:344–346
33. Devogelaer JP, Goemaere S, Boonen S, Body JJ, Kaufman JM,
Reginster JY, Rozenberg S, Boutsen Y (2006) Evidence-based
guidelines for the prevention and treatment of glucocorticoid-
induced osteoporosis: a consensus document of the Belgian Bone
Club. Osteoporos Int 17:8–19
34. van Staa TP, Leufkens HG, Abenhaim L, Zhang B, Cooper C
(2000) Oral corticosteroids and fracture risk: relationship to daily
and cumulative doses. Rheumatology 39:1383–1389
35. Steinbuch M, Youket TE, Cohen S (2004) Oral glucocorticoid use
is associated with an increased risk of fracture. Osteoporos Int
15:323–328
Osteoporos Int (2010) 21:1247–1255 1255
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