Osteoporosis as a risk factor for distal radial fractures: a case-control study.

Abstract

Distal radial fractures occur earlier in life than hip and spinal fractures and may be the first sign of osteoporosis. The aims of this case-control study were to compare the prevalence of osteopenia and osteoporosis between female and male patients with low-energy distal radial fractures and matched controls and to investigate whether observed differences in bone mineral density between patients and controls could be explained by potential confounders.
Six hundred and sixty-four female and eighty-five male patients who sustained a distal radial fracture, and 554 female and fifty-four male controls, were included in the study. All distal radial fractures were radiographically confirmed. Bone mineral density was assessed with use of dual x-ray absorptiometry at the femoral neck, total hip (femoral neck, trochanter, and intertrochanteric area), and lumbar spine (L2-L4). A self-administered questionnaire provided information on health and lifestyle factors.
The prevalence of osteoporosis was 34% in female patients and 10% in female controls. The corresponding values were 17% in male patients and 13% in male controls. In the age group of fifty to fifty-nine years, 18% of female patients and 5% of female controls had osteoporosis. In the age group of sixty to sixty-nine years, the corresponding values were 25% and 7%, respectively. In adjusted conditional logistic regression analyses, osteopenia and osteoporosis were significantly associated with distal radial fractures in women. Osteoporosis was significantly associated with distal radial fractures in men.
The prevalence of osteoporosis in patients with distal radial fractures is high compared with that in control subjects, and osteoporosis is a risk factor for distal radial fractures in both women and men. Thus, patients of both sexes with an age of fifty years or older who have a distal radial fracture should be evaluated with bone densitometry for the possible treatment of osteoporosis.

Full text

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Osteoporosis as a Risk Factor
for Distal Radial Fractures
A Case-Control Study
By Jannike Øyen, MSc, Christina Brudvik, PhD, MD, Clara Gram Gjesdal, PhD, MD,
Grethe S. Tell, PhD, MPH, Stein Atle Lie, PhD, MSc, and Leiv M. Hove, PhD, MD
Investigation performed at the Departments of Orthopedic Surgery and Rheumatology, Haukeland University Hospital,
Bergen, and the Bergen Accident and Emergency Department, Bergen, Norway
Background: Distal radial fractures occur earlier in life than hip and spinal fractures and may be the first sign of
osteoporosis. The aims of this case-control study were to compare the prevalence of osteopenia and osteoporosis
betweenfemaleandmalepatientswithlow-energy distalradialfracturesandmatchedcontrolsandtoinvestigatewhether
observed differences in bone mineral density between patients and controls could be explained by potential confounders.
Methods: Six hundred and sixty-four female and eighty-five male patients who sustained a distal radial fracture, and 554
female and fifty-four male controls, were included in the study. All distal radial fractures were radiographically confirmed.
Bone mineral density was assessed with use of dual x-ray absorptiometry at the femoral neck, total hip (femoral neck,
trochanter, and intertrochanteric area), and lumbar spine (L2-L4). A self-administered questionnaire provided information
on health and lifestyle factors.
Results: Theprevalenceofosteoporosiswas34%infemalepatientsand10%infemalecontrols.Thecorrespondingvalues
were17%inmalepatientsand13%inmalecontrols.Intheagegroupoffiftytofifty-nineyears,18%offemalepatientsand5%
of femalecontrolshadosteoporosis.Intheagegroupof sixty tosixty-nineyears,thecorrespondingvalueswere25% and7%,
respectively. In adjusted conditional logisticregression analyses, osteopenia and osteoporosiswere significantly associated
with distal radial fractures in women. Osteoporosis was significantly associated with distal radial fractures in men.
Conclusions: The prevalence of osteoporosis in patients with distal radial fractures is high compared with that in control
subjects, and osteoporosis is a risk factor for distal radial fractures in both women and men. Thus, patients of both sexes
with an age of fifty years or older who have a distal radial fracture should be evaluated with bone densitometry for the
possible treatment of osteoporosis.
Level of Evidence: Prognostic Level III. See Instructions to Authors for a complete description of levels of evidence.
T
is high4.
heincidenceofdistalradialfracturesinNorwayisamong
the highest in the world1-3, and the prevalence of low
bone mineral density and osteoporosis in these patients
Patients with low-energy distal radial fractures are at
increasedriskforsubsequenthipandspinalfractures5,6.Known
risk factors for distal radial fractures include previous low-
energy fracture7-9and a family history of fracture10. The use of
estrogen-replacement therapy7,10-14and high body-mass in-
dex8,11,15seem to have protective effects. Distal radial fractures
occur earlier in life than hip and spinal fractures do5, although
studies have demonstrated that low bone mineral density exists
in a high proportion of patients with a distal radial fracture7,11,
indicating that this type of fracture might be the first presen-
tation of osteoporosis. Currently, such patients are often not
evaluated and treated for osteoporosis16-18.
How the prevalence of low bone mineral density and os-
teoporosis in patients with low-energy distal radial fractures4,19-21
compares with that of individuals without such fractures is not
well known. We are not aware of any large published studies
comparing the bone mineral density in patients who have distal
radial fractures with that in comparable controls of both sexes.
Disclosure: In support of their research for or preparation of this work, one or more of the authors received, in any one year, outside funding or grants in
excess of $10,000 from The Research Council of Norway, the University of Bergen, and The Western Norway Health Authority. Neither they nor a member
of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity.
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The aim of this case-control study was to compare the
prevalence of osteopenia and osteoporosis in female and male
patients who had low-energy distal radial fractures with that in
sex and age-matched controls. Furthermore, we wanted to ex-
amine whether observed differences between patients and con-
trols with regard to bone mineral density could be explained by
potential confounders.
Materials and Methods
Study Design and Study Population
P
middle-aged and elderly women and men with low-energy
distal radial fractures and control subjects who were randomly
selected from the general population in the same area. Patients
were recruited from the Bergen Accident and Emergency De-
partmentand Haukeland University Hospital, located in the city
of Bergen, Norway. The hospital’s osteoporosis clinic is orga-
nized according to the Fracture Liaison Service model4,20,22. Ac-
cording to a standard protocol, all patients with an age of fifty
years or older who had a low-energy distal radial fracture from
October 2003 untilOctober2007were invited,atthetimeof the
fracture, to the osteoporosis clinic for the assessment of osteo-
porosis with use of dual x-ray absorptiometry and the deter-
mination of a clinical risk score with use of a self-administered
questionnaire. The attending physician at the Bergen Accident
and Emergency Department received automatic reminders
throughtheelectronicmedicalrecord.Inthecaseofemergency
treatment at the Department of Orthopedic Surgery at Hauke-
land University Hospital, diagnoses and patient data were made
availableonthetwenty-four-hourshiftlistsandpatientsreceived
the invitation after the treatment. Patients were informed that
osteoporosiscouldbeapossiblediagnosisgiventhenatureofthe
fracture, and they were offered a referral to the osteoporosis
clinic for the measurement of bone mineral density.
articipants in the present case-control study included
Patients
During the four-year period from October 2003 until October
2007, 1252 female and 185 male patients with an age of fifty
years or older who had a low-energy distal radial fracture were
registered and evaluated for the study at the Bergen Accident
and Emergency Department and Haukeland University Hos-
pital. Ofthese,117femaleandfourmalepatientswereunwilling
to participate because they had previously been evaluated for
osteoporosis. Another 230 female and sixty-one male patients
did not want to participate, for unknown reasons. Thirty-five
women and seven men were not included because they were
tourists. Furthermore,194 women and twenty-seven menwere
not able to participate because of confusion, dementia, serious
illness, or hospitalization. We chose to exclude five female pa-
tientswhoweremorethan ninety yearsold because no controls
were more than ninety years old. Seven women and one man
who had the examination at the osteoporosis clinic more than
six months after the current distal radial fracture were also
excluded. Thus, the final study sample comprised 664 female
andeighty-fivemalepatientswithanageoffifty toninetyyears.
Ninety percent of the patients were referred from the Bergen
Accident and Emergency Department and 10% were referred
from Haukeland University Hospital. The average time between
the fracture and the examination at the osteoporosis clinic
was sixty-six days (range, six to 169 days) for female patients
and sixty-three days (range, eighteen to 156 days) for male
patients.
A low-energy fracture was defined as a fracture that was
sustained after minor trauma, such as falling from standing
height or lower23. All distal radial fractures were confirmed on
radiographs.
Controls
Controls were randomly selected by Statistics Norway with use
of the Norwegian Population Register and were matched on the
basisofthetownofresidency,age(plusorminustwoyears),sex,
and the month of examination. These subjects were invited by
mailto participateandwereincludedfromApril2008untilJune
2009. We invited twice as many controls as there were patients.
Specifically, 1352 women and 172 men were invited, and, of
these, 612 women and fifty-five men agreed to participate.
Controlsubjectswithapreviouslow-energydistalradialfracture
after the age of fifty years (including fifty-four women and one
man)wereexcluded.Inthecasesoffourfemalecontrols,neither
hip nor spine scans could be used because of a bilateral hip
fracture,surgery,ordegenerativechangesinthespine.Thus,554
female and fifty-four male control subjects were included.
The study was approved by the National Data Inspec-
torate (10117) and the Regional Committee for Medical Re-
search Ethics (122.03). Each participant signed an informed
consent form.
Demographic and Clinical Data
Weight and height were measured at the osteoporosis clinic. A
self-administered questionnaire provided information regarding
previous and current smoking and medical illness, including
rheumatoid arthritis, endocrine diseases, and cardiovascular dis-
eases. Information about the use of glucocorticoids and bis-
phosphonates, history of hip fracture in a parent, and previous
fractures also were included in the questionnaire. Previous
fractures were defined as fractures of the proximal part of the
arm, rib, spine, hip, distal part of the femur, or leg resulting
from low-energy trauma after the age of fifty years. The dif-
ference between the examined height and the self-reported
maximum adult heightwas calculated.In addition, for women,
the age at menopause, the use of selective estrogen receptor
modulators, and the use of postmenopausal estrogen therapy
were recorded. Natural loss of regular menstruation before the
ageofforty-fiveyearswasdefinedasearly menopause(TableI).
Bone Mineral Density Measurements
Bone mineral density was measured at the femoral neck, total
hip (femoral neck, trochanter, and intertrochanteric area), and
lumbar spine (L2-L4). All scans and analyses were conducted
by two trained nurses with use of the same protocol. The same
dual x-ray absorptiometry equipment (GE Prodigy; Lunar
Corporation, Madison, Wisconsin) was used during the entire
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TABLE I Demographic Variables, Clinical Characteristics, and Bone Mineral Density Measurements in Patients with Distal Radial
Fractures and Controls*
Female Male†
Patients
(N = 664)
Controls
(N = 554)
P
Value
Patients
(N = 85)
Controls
(N = 54)
P
Value
Demographic Variables
Age‡ (yr)
Height‡ (cm)
Weight‡ (kg)
BMIठ(kg/m2)
BMI§ <22 kg/m2(no. of
patients or controls)
Smoking (no. of patients or controls)
Previous
Current
66 ± 10
163 ± 6
68 ± 12
25 ± 4
140 (21%)
65 ± 8
164 ± 6
71 ± 13
27 ± 5
93 (17%)
0.032
0.012
<0.001
<0.001
0.067
65 ± 10
178 ± 8
82 ± 14
26 ± 4
13 (15%)
67 ± 8
178 ± 7
86 ± 16
27 ± 4
4 (7%)
0.199
0.690
0.167
0.093
0.194
170 (26%)
105 (16%)
142 (26%)
97 (18%)
1.000
0.440
28 (33%)
23 (27%)
28 (52%)
7 (13%)
0.034
0.058
Clinical characteristics
(no. of patients or controls)
Rheumatoid arthritis
Endocrine diseases
Cardiovascular diseases
Diabetes
Type I
Type II
Glucocorticoids
Previous
Current
Estrogen
Bisphosphonates/SERM#
Calcium supplements
Vitamin-D supplements
Loss of adult height (‡3 cm)
Menopause <45 yr
Previous fracture
History of hip fracture in a parent
12 (2%)
63 (10%)
33 (5%)
8 (1%)
42 (8%)
15 (3%)
0.658
0.260
0.054
03 (6%)
1 (2%)
7 (13%)
—
1 (1%)
12 (14%)
1.000
1.000
1 (<1%)
21 (3%)
8 (1%)
22 (4%)
0.014
0.553
———
5 (6%)4 (7%) 0.735
31 (5%)
7 (1%)
19 (3%)
55 (8%)
141 (21%)
129 (19%)
182 (29%)
96 (15%)
183 (28%)
57 (9%)
20 (4%)
10 (2%)
3 (1%)
23 (4%)
104 (19%)
99 (18%)
106 (20%)
56 (10%)
81 (15%)
70 (13%)
0.391
0.329
0.002
0.003
0.315
0.507
<0.001
0.024
<0.001
0.023
———
—
NA
0
—
NA
—
—
1 (2%)
1 (2%)
6 (11%)
12 (25%)
NA
7 (13%)
6 (11%)
—
5 (6%)
8 (9%)
21 (26%)
NA
0
4 (5%)
0.405
0.778
1.000
—
—
0.186
BMD**
BMD‡ (g/cm2)
Femoral neck
Total hip
L2-L4
Femoral neck (no. of
patients or controls)
Normal BMD
Osteopenia
Osteoporosis
Total hip (no. of patients or controls)
Normal BMD
Osteopenia
Osteoporosis
L2-L4 (no. of patients or controls)
Normal BMD
Osteopenia
Osteoporosis
0.78 ± 0.12
0.82 ± 0.12
0.99 ± 0.17
0.84 ± 0.13
0.89 ± 0.14
1.08 ± 0.19
<0.001
<0.001
<0.001
<0.001††
0.85 ± 0.10
0.92 ± 0.12
1.08 ± 0.17
0.90 ± 0.13
0.98 ± 0.15
1.23 ± 0.23
0.014
0.024
<0.001
0.151††
105 (16%)
326 (50%)
223 (34%)
217 (40%)
275 (50%)
54 (10%)
17 (20%)
54 (64%)
14 (17%)
19 (35%)
28 (52%)
7 (13%)
<0.001††
0.329††
191 (29%)
341 (52%)
122 (19%)
275 (50%)
230 (42%)
41 (8%)
32 (38%)
48 (57%)
5 (6%)
27 (50%)
25 (46%)
2 (4%)
<0.001††
<0.001††
179 (27%)
257 (39%)
223 (34%)
234 (43%)
215 (39%)
98 (18%)
29 (35%)
35 (42%)
19 (23%)
37 (71%)
10 (19%)
5 (10%)
*The total numbers in the various cells may vary slightly because of missing data. †NA = not applicable. ‡The values are given as the mean and the standard
deviation.§BMI = body-mass index.#SERM = selective estrogen receptor modulators.**BMD = bone mineral density. A normal BMD is defined as a T score of –1.0
or greater, osteopenia is defined as a T score of less than –1.0 or more than –2.5, and osteoporosis is defined as a T score of –2.5 or less.††Overall p value for the
actual categorized variable.
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study period. The main results were based on measurements
of femoral neck bone mineral density as this measurement site
is recommended as the reference standard24. The densitometer
was calibrated daily and was stable during the entire mea-
surementperiod.Theinvitrolong-termcoefficientofvariation
was 0.9%. The in vivo short-term precision for femoral neck,
total hip, and spine measurements was 1.5%, 0.8%, and 1.4%,
respectively. Bone mineral density values for the left hip were
used unless there was a history of previous fracture or surgery.
Scansfromtherighthipwereusedfor twenty-sevenfemaleand
four male patients and for eight female controls and one male
control. Bone mineral density scans of the hip were missing for
ten female patients and eight female controls because of a
previous bilateral hip fracture or a prosthesis. For five female
and two male patients and for eleven female and two male
controls, spine scans could not be analyzed because of massive
degenerative changes. Bone mineral density was categorized
according to different levels of the T score. The T score is de-
fined as the number of standard deviations above the mean
value for healthy thirty-year-old adults of the same sex and eth-
nicity as the patient25. The Tscore calculations were derived from
a combined European/United States reference population sup-
plied by the dual x-ray absorptiometry manufacturer Lunar26,27.
The T scores for men were determined from the database of
young healthy men. Osteoporosis and osteopenia were defined
according to World Health Organization definitions; specifi-
cally, osteoporosis was defined as a Tscore of –2.5 or less and
osteopenia was defined as a T score of –1.0 or less but more
than –2.5. Normal bone mineral density was defined as a T
score of –1.0 or more25.
Statistical Methods
Categorical variables are expressed as numbers and percent-
ages. Continuous variables are expressed as means, with vari-
ation expressed as the standard deviation and/or range. Height
change during adulthood was dichotomized at 3 cm. The age
groups were stratified at fifty to sixty-four years and sixty-five
to ninety years. We used independent-sample t tests for con-
tinuous variables and chi-square tests for categorical variables
for comparisons between patients and controls and different
age groups. Odds ratios (OR) and 95% confidence intervals
(95%CI)fordistalradialfracturewereestimatedinunadjusted
conditional logistic regression analyses separately for the dif-
ferent demographic and clinical risk factors. Variables from the
TABLE II Factors Associated with Distal Radial Fractures in Women on Unadjusted and Adjusted Conditional Logistic Regression
Analyses*†
Unadjusted Adjusted‡
OR (95% CI) P ValueOR (95% CI) P Value
BMD femoral neck§
Normal
Osteopenia
Osteoporosis
1
2.7 (1.9 to 3.9)
7.1 (4.3 to 11.6)
1
2.7 (1.9 to 3.9)
6.8 (4.1 to 11.2)
<0.001
<0.001
<0.001
<0.001
BMI
‡22 kg/m2
<22 kg/m2
1
1.34 (0.9 to 1.9)
1
1.0 (0.7 to 1.5)0.098 0.954
Hip fracture in a parent
No
Yes
1
0.7 (0.5 to 1.1)
1
0.7 (0.4 to 1.1)0.106 0.093
Previous low-energy
fracture
No
Yes
1
1.6 (1.1 to 2.3)
1
1.5 (1.0 to 2.2)0.010 0.050
Menopause
‡45 yr
<45 yr
1
1.5 (1.0 to 2.3)
1
1.5 (0.9 to 2.4)0.042 0.064
Current smoking
No
Yes
1.0
1 (0.7 to 1.4)1.000
*The analysis included 664 patients and 554 controls.†OR = odds ratio, CI = confidence interval, BMD = bone mineral density, BMI = body-mass
index.‡Variables that were included in the adjusted model included osteopenia, osteoporosis, a body-mass index of <22, hip fracture in a parent,
previous low-energy fracture, and menopause at an age of less than forty-five years. §A normal BMD is defined as a T score of –1.0 or greater,
osteopenia is defined as a T score of less than –1.0 or more than –2.5, and osteoporosis is defined as a T score of –2.5 or less.
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unadjusted analyses with a p value of £0.20 were included in
the adjusted analyses. Two-tailed p values of <0.05 were con-
sidered significant.
Source of Funding
This workwassupportedbyresearch grants from TheResearch
Council of Norway, the University of Bergen, and The Western
Norway RegionalHealthAuthority.The fundswereused topay
the salaries of the health personnel who conducted measure-
ments on the recruited control group.
Results
Characteristics of Patients and Controls
Women
T
weight and height than the female control subjects (Table
I). However, the age and height differences were small and
probably were not clinically relevant. The use of postmeno-
pausal estrogentherapy,bisphosphonates,andselectiveestrogen
receptor modulators was higher among patients than controls,
and more patients than controls reported early menopause
(Table I). A higher proportion of patients reported previous
low-energy fracture than controls (28% compared with 15%;
p < 0.001). However, a higher proportion of controls than
patients reported a history of hip fracture in a parent (13%
compared with 9%; p = 0.023).
he female patients were significantly older and had a lower
Men
Compared with male controls, a lower proportion of male
patients reported previous smoking (Table I).
Prevalence of Osteopenia and Osteoporosis and Bone
Mineral Density Measurements in Patients and Controls
Women
The female patients had significantly lower mean bone min-
eral density and higher prevalence of osteopenia and osteo-
porosis thanthe controls atallmeasurementsites. Overall,the
prevalence of osteoporosis at the femoral neck measurement
site was 34% in patients and 10% in controls. The prevalence
of osteopeniawas 50% in both patients and controls (Table I).
A total of 18% and 25% of patients in the age groups of
fifty to fifty-nine years and sixty to sixty-nine years had osteo-
porosis at the femoral neck, compared with 5% and 7% of
controls, respectively (Fig. 1). Among women who were fifty
to sixty-four years old, the prevalence of osteoporosis at the
femoral neck was 18% in patients and 6% in controls; the
corresponding values for osteopenia were 59% and 46%, re-
spectively. In the age group of sixty-five to ninety years, 51% of
patients and 14% of controls had osteoporosis and 40% of
patients and 55% of controls had osteopenia.
Men
The prevalence of osteoporosis at the femoral neck was 17% in
male patients and 13% in male controls; the corresponding
valuesforosteopeniawere64%and52%,respectively(TableI).
Male patients had lower mean bone mineral density at all
measurement sites as compared with controls (Table I). The
prevalenceofosteopeniaatL2-L4was42%inpatientsand19%
in controls; the corresponding values for osteoporosis were
23% and 10%, respectively. Among men who were fifty to
sixty-four years old, 14% of patients and 11% of controls had
TABLE III Factors Associated with Distal Radial Fractures in Men on Unadjusted and Adjusted Conditional Logistic Regression Analyses*†
Unadjusted Adjusted‡
OR (95% CI) P Value OR (95% CI)P Value
BMD femoral neck§
Normal
Osteopenia
Osteoporosis
1
3.4 (1.1 to 10.5)
8.5 (1.6 to 44.7)
1
3.1 (1.0 to 9.8)
8.1 (1.4 to 47.4)
0.032
0.011
0.051
0.021
BMI
‡22 kg/m2
<22 kg/m2
1
2.5 (0.7 to 9.8)
1
2.6 (0.5 to 12.3) 0.1830.238
Current smoking
No
Yes
1
2.6 (0.9 to 6.8)
1
1.6 (0.5 to 5.1)0.0600.386
Hip fracture in a parent
No
Yes
1
0.8 (0.1 to 2.3)0.437
*The analysis included eighty-five patients and fifty-four controls.†OR = odds ratio, CI = confidence interval, BMD = bone mineral density, BMI =
body-mass index.‡Variables that were included in the adjusted model included osteopenia, osteoporosis, a body-mass index of <22, and current
smoking.§A normal BMD is defined as a T score of –1.0 or greater, osteopenia is defined as a T score of less than –1.0 or more than –2.5, and
osteoporosis is defined as a T score of –2.5 or less.
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osteoporosis measured at the femoral neck; the corresponding
values among menwho were sixty-five to ninety years old were
20% and 15%, respectively (Fig. 2).
Factors Associated with Distal Radial Fractures
Women
In unadjusted conditional logisticregression models, distalradial
fracturesweresignificantlyassociatedwithosteopenia(OR = 2.7;
95% CI, 1.9 to 3.9; p < 0.001), osteoporosis (OR = 7.1; 95% CI,
4.3 to 11.6; p < 0.001), previous low-energy fracture (OR = 1.6;
95% CI, 1.1 to 2.3; p = 0.010), and early menopause (OR = 1.5;
95% CI, 1.0 to 2.3; p = 0.042). In analyses adjusted for previous
low-energy fracture, early menopause, body-mass index, and hip
fracture in a parent, only osteopenia (OR = 2.7; 95% CI, 1.9 to
3.9; p < 0.001) and osteoporosis (OR = 6.8; 95% CI, 4.1 to 11.2;
p<0.001)weresignificantlyassociatedwithdistalradialfractures
(Table II).
When these analyses were repeated after stratification
accordingtotheagegroupsoffiftytosixty-four yearsandsixty-
five to ninety years, significant variables in the fully adjusted
model included osteoporosis (OR = 5.9; 95% CI, 2.5 to 14.3;
p < 0.001) and previous fracture (OR = 3.5; 95% CI, 1.8 to 6.7;
p < 0.001) in the older group and osteopenia (OR = 3.2; 95%
CI, 2.0 to 5.2; p < 0.001) and osteoporosis (OR = 7.1; 95% CI,
3.1 to 16.0; p < 0.001) in the younger group.
When the analyses were repeated after the exclusion of
participants who had received bone-active drugs (bisphos-
phonates, selective estrogen receptor modulators, estrogen),
the results did not change materially (data not shown).
Men
In unadjusted conditional logistic regression models, osteopenia
(OR = 3.4; 95% CI, 1.1 to 10.5; p = 0.032) and osteoporosis
(OR = 8.5; 95% CI, 1.6 to 44.7; p = 0.011) were significantly
associated with distal radial fractures. In analyses adjusted for
current smoking and body-mass index, only osteoporosis was
significantly associated with distal radial fractures (OR = 8.1;
95% CI, 1.4 to 47.4; p = 0.021) (Table III).
Fig. 1
Fig. 1 Graph illustrating the prevalence of normal bone mineral density, osteopenia, and osteoporosis at the femoral neck in female patients with distal
radialfracturesandmatchedcontrols.BMD=bonemineraldensity.Fig.2Graphillustratingtheprevalenceofnormalbonemineraldensity,osteopenia,and
osteoporosis at the femoral neck in male patients with distal radial fractures and matched controls. BMD = bone mineral density.
Fig. 2
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Discussion
I
prevalence of osteopenia and osteoporosis in female patients
with distal radial fractures as compared with female controls at
all measurement sites. Even female patients in the younger age
group had a much higher prevalence of osteoporosis as com-
pared with their female age-matched controls. Both osteopenia
and osteoporosis were associated with distal radial fractures
in women. Osteoporosis was also associated with distal radial
fractures in men. These findings persisted after adjustment for
body-mass index, smoking, family disposition for hip fracture,
and other known risk factors for fracture. Thus, osteoporosis
seems to be an independent risk factor for fracture.
To our knowledge, the present case-control study is the
largest to compare the bone mineral density in female patients
who had distal radial fractures with that in matched controls.
Normative data supplied by the manufacturerof densitometers
are based on a healthy normal population from the United
StatesandEuropeandmaynotberepresentativeofmembersof
the Norwegian population, whosustain morefragility fractures
than do members of other populations3,28,29. Within Norway,
regional differences in hip bone mineral density have been
found, withlowerhipbonemineraldensityamong womenand
men with an age of sixty years or more from Bergen as com-
pared with those from Tromsø30. Thus, we determined that it
was important to include a control group from the same geo-
graphical area as that of the patients who had a distal radial
fracture. The rationale for the inclusion of two matched con-
trols for each patient was to minimize potential bias due to low
attrition. However, despite the considerable number of female
participants, selection bias still may have affected our results as
the participation rate was 52% among the patients and 40%
among the controls. A high proportion of female patients had
previously been evaluated for osteoporosis and therefore did
not consider participation in this study as meaningful. If alarge
proportion of those who declined to participate already were
diagnosed with osteoporosis, the prevalence of osteoporosis in
our study may have been underestimated; subsequently, the
magnitude of the differences in bone mineral density between
patients and controls might be underestimated. On the other
hand, the reasons why invited control subjects did not partic-
ipate are not known, and some control subjects also may have
declined participation because of existing osteoporosis. If this
were the case, the prevalence of osteoporosis may have been
underestimated in that group as well. The latter presumption is
supported by the study by Buist et al.31, who, in a population-
based osteoporosis screening program, found that nonpartic-
ipants were postmenopausal high-risk women with previous
fractures who were not receiving osteoporosis therapy. Hence,
selection bias might have affected both patients and controls in
ourstudy;however,themagnitudeofpossible underestimation
of osteoporosis and the influence on the results are unknown.
Our control subjects were included six months to four years
after the patients had their bone mineral density measured.
However, all participants were examined at the same osteo-
porosis clinic, by the same personnel, in the same month of the
n the present matched case-control study, we found a higher
year as their matched patients, and with use of the same dual
x-ray absorptiometry device. The densitometer was calibrated
daily against a standard aluminum spine phantom, and the
phantom measurements showed no drift during the study
period. Thus, the results are probably not affected by the time
of inclusion. Retrospective data collection may be biased by
recall problems, and this may have influenced the information
on some of the clinical variables, e.g., previous fractures and
menopause before the age of forty-five years.
Comparisons with other studies are complicated because
bone mineral density measurement sites differ between stud-
ies32-36.The prevalenceof osteoporosis inwomenin ourstudy is
inaccordancewiththefindingsreportedbyKanterewiczetal.34,
who investigated fifty-eight female patients with distal radial
fractures and eighty-three controls with an age of forty-five to
eighty years. In that study, bone density measurement of the
hipshowedthat19% ofthepatientsand6%ofthe controlshad
osteoporosis (p < 0.005). When the participants were divided
into age groups (sixty-five years of age or less and more than
sixty-five years of age) and the data were adjusted for age,
menopausal status, and body-mass index, osteopenia and os-
teoporosis were found to be significantly associated with distal
radial fracture only in the younger age group. In the present
study, osteoporosis and previous fracture were significantly
associated with distal radial fracture in the older age group and
osteopenia and osteoporosis were significantly associated with
distal radial fracture in the younger age group.
Theprevalenceofosteoporosisinourtotalgroupwasnot
significantly different between the male patients and male
controls (17% compared with 13%; p = 0.174). However, in
adjusted conditional logistic regression analysis in which
matched pairs were taken into account, osteoporosis was sig-
nificantly associated with low-energy distal radial fracture
(OR=8.1;95%confidenceinterval,1.4to47.4;p=0.021).Tuck
et al.37found a higher prevalence of osteoporosis at the fem-
oral neck in sixty-seven male patients with distal radial frac-
turesascomparedwith198controls(37%comparedwith9%;
p < 0.001), and, in regression analyses, the authors found a
lower bone mineral density in the patients with distal radial
fractures than in controls after adjustment for age and body-
mass index.
Unlikehip fractures,distalradialfracturesarenotstrongly
associated withincreasedmortality38.However,inpatientswith
low-energy distal radial fractures, low bone mineral density is
associated not only withincreased fracturerisk butalsowithan
increasedseverityofdistalradialfracture39.Becausedistalradial
fractures occur an average fifteen years earlier in life than hip
fractures40, distal radial fractures may predict both subsequent
vertebral and hip fractures5. To reduce the risk of later hip and
vertebral fracture, it may be clinically appropriate to identify
and monitor patients with distal radial fractures for possible
indications for the treatment of osteoporosis5,41. In a previous
study, we found that treatment decisions had to be based on
bone mineral density and not merely on clinical guidelines or
the assessment of future fracture risk without the use of bone
mineral density4.
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Studies have shown that pharmacological bisphosphonate
therapy reduces the fracture risk in postmenopausal women42-44
as well as vertebral fracture risk in middle-aged and elderly
men with primary osteoporosis45. However, only 3% to 20%
ofpatientswithdistalradialfracturesduetolow-energy trauma
are evaluated for osteoporosis with use of bone densitometry
and only 8% to 30% are managed for osteoporosis with medi-
cation16,18,46. Because of cognitive or functional impairments and
frequentadministration requirementsoforalbisphosphonates,
the compliance is low and the disease remains untreated47-49.
However, a once-yearly intravenous infusion of zoledronic
acid has been shown to be effective43,50,51and safe in elderly
women51.
Furthermore, today’s osteoporosis treatment aims at re-
ducing the damage after the condition is established, and the
lackofacureshouldleadtoafocusonpreventivemeasuresand
an increasing interest in a possible protective effect of nutrition
and physical activity. Fall prevention to reduce the risk of
fracture should also be emphasized. Hopefully, our study will
add to the increasing understanding of the important role of
osteoporosis, especially among clinicians who treat distal radial
fractures. This large case-control study demonstrated that os-
teoporosis among both women and men, and osteopenia
among women, are related to distal radial fractures in patients
with an age of fifty to ninety years. The prevalence of osteo-
porosis was much higher in these patients than in matched
controlsubjects.Thisfinding impliesthatpatientsofbothsexes
with an age of fifty years and older who have a distal radial
fracture should be referred for bone mineral density assess-
ments and evaluated for possible osteoporosis in order to re-
ceive the recommended treatment to reduce the risk of new
fractures. n
NOTE: The authors are grateful to the medical staff at Bergen Accident and Emergency Department,
the Department of Orthopedic Surgery at Haukeland University Hospital, and the technicians at the
osteoporosis clinic at the Department of Rheumatology at Haukeland University Hospital.
Jannike Øyen, MSc
Christina Brudvik, PhD, MD
Stein Atle Lie, PhD, MSc
Leiv M. Hove, PhD, MD
Department of Surgical Sciences, University of Bergen,
N-5021 Bergen, Norway.
E-mail address for J. Øyen: jannike.oyen@kir.uib.no.
E-mail address for C. Brudvik: Christina.brudvik@kir.uib.no.
E-mail address for S.A. Lie: stein.lie@smis.uib.no.
E-mail address for L.M. Hove: leiv.hove@kir.uib.no
Clara Gram Gjesdal, PhD, MD
Department of Rheumatology,
Haukeland University Hospital,
N-5021 Bergen, Norway.
E-mail address: clara.gjesdal@helse-bergen.no
Grethe S. Tell, PhD, MPH
Department of Public Health and Primary Health Care,
University of Bergen, N-5018 Bergen, Norway.
E-mail address: grethe.tell@isf.uib.no
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