Abstract
Background:
Osteoporosis is a common bone disease that increases with age. Wrist bone mineral density (BMD) has significant correlation with other skeletal sites and it could be used as a diagnostic method for osteoporosis. The purpose of this study was to evaluate the role of wrist BMD in diagnosing osteoporosis in postmenopausal women.
Methods:
In this cross-sectional study, 99 postmenopausal women with mean age of 57 ± 6.9 (range 50–76) years were evaluated. BMD of nondominant wrist, lumbar spine (L2–L4) and femur bone using a dual-energy X-ray absorptiometry (DXA) device as well as lateral lumbosacral X-ray for degenerative joint disease (DJD) evaluation were measured. Mean T-score of wrist was lower than hip and lumbar area.
Results:
Osteopenia and osteoporosis were observed in 40.4% and 59.6% in the wrist, 38.4% and 24.2% in the hip and 36.4% and 49.5% in lumbar-spine BMD measurements, respectively. There was positive correlation between wrist BMD with hip BMD (r = 0.468,p < 0.001) and lumbar BMD (r = 0.322, p = 0.001). DJD due to lumbosacral X-ray was reported in 84 cases (84.8%) including mild DJD in 45 (53.5%), moderate DJD in 33 (39.3%) and severe DJD in 6 (7.2%).
Conclusions:
Our results showed that wrist BMD has better accuracy than lumbar BMD in diagnosing osteoporosis in postmenopausal women.
Background
Osteoporosis in postmenopausal women is a common public health problem worldwide and its incidence increases with age. Osteoporosis is characterized by systemic destruction of bone mass, strength and microstructures that `increase the probability of fragile fractures [Siris et al. 2014]. Osteoporosis evaluation includes BMD measurement and risk stratification in hip and lumbar spine [Kanis et al. 2005; Siris et al. 2005]. These two are used for measurement of T-score of hip and spine [Kanis et al. 2008]. Dual-energy X-ray absorptiometry (DXA) has become the gold standard technique for assessing BMD in postmenopausal women and the definitions of osteopenia (T-score between -1 and -2.5) and osteoporosis (T-score < -2.5) are based on its results [Kanis et al. 2005, 2008; Laster, 2014].
Wrist osteoporosis and fracture is common among postmenopausal women. It is observed that women less aged less than 66 years with wrist fracture have considerably low BMD in hip [Earnshaw et al. 1998]. Densitometric evaluation of wrist is shown to be a useful technique. Rey and colleagues compared wrist densitometry with hip and lumbar densitometries and observed significant correlation between wrist BMD and hip and lumbar BMD [Rey et al. 1994]. It is possible to evaluate wrist BMD instead of standard BMD evaluations for disease evaluation, and recommend treatment protocols.
In this study we aim to evaluate wrist osteoporosis and osteopenia incidence among Iranian postmenopausal women and compare the results with hip and lumbar BMD results.
Materials and methods
In this study, postmenopausal women visiting physical medicine and rehabilitation clinics of Tabriz Shohada Hospital, Iran, who were referred for BMD measurement between August 2011 and August 2012, and not having the exclusion criteria, were studied. A total of 300 women were evaluated and those meeting the study criteria comprised 100 women, who were recruited. One woman failed to fulfill all evaluations; the study was completed with 99 cases. Women were considered postmenopausal if they met one or more of the following criteria: (1) age ⩾ 55; (2) self-report of natural menopause; (3) self-report of surgical menopause involving bilateral oophorectomy; or (4) self-reported current use of hormone therapy (HT). The referral reasons for BMD measurement were women aged 65 and over (25 women), postmenopausal women age 50 and over with fracture after menopause, mostly in the skull, facial bone and ankle (40 cases), women with rheumatoid arthritis (20 cases), and with lower BMI (below 21 kg/m2) (14 cases). All postmenopausal women aged between 50 and 80 years with no history of postmenopausal HT or prior history of nonwrist fractures were included. Patients with a history of bisphosphonate and raloxifene use of more than 2 years, use of teriparatide, history of any wrist or nonwrist fracture, severe degenerative joint disease (DJD) of the wrist due to the patient’s complaint and physical examination, connective-tissue disease with erosive decrement of the wrist, and clinical signs and symptoms of connective-tissue disease were excluded. The study was approved by The Institutional Review Board of Tabriz University of Medical Sciences and informed written consents were obtained from all patients.
Demographic and anthropometric information was recorded in a checklist. All women underwent BMD evaluation of nondominant wrist, lumbar spine and femur, as well as lumbosacral lateral X-ray. Height and weight were measured in our center before DXA measurement with light, indoor clothes on, but without shoes. Body mass index (BMI) was calculated by dividing weight in kilograms by height in meters squared.
BMD was measured using a DXA device (MEDI LINK Osteocore 2 system, France). Lumbar spine (anteroposterior, L2–L4), right proximal femur (neck, trochanter, Ward’s triangle) and wrist scans in the nondominant hand were performed according to the manufacturer’s procedures. All BMD measurements were performed at one visit and by the same technician. Cases were classified as normal, osteopenic bone, osteoporotic bone and severely osteoporotic bone according to World Health Organization criteria. However, we found no cases of severe osteoporosis among our patients. Patients were diagnosed as having osteoporosis when the minimum T-score, measured at any site, was less than -2.5, osteopenia if T-score between -1 and -2.5 and normal if T-score was greater than -1 according to the World Health Organization guideline [World Health Organization, 2004].
Lumbosacral lateral X-ray was used to define DJD changes. We defined patients with DJD into three groups: mild (existence of lipin in the margin of vertebrae), moderate (existence of sclerosis in the margin of vertebrae and distinct osteophyte), severe (existence of large osteophyte with severe sclerosis of the margin of vertebrae).
Statistical analysis
All data were analyzed using the Statistical Package for Social Sciences, version 17.0 (SPSS, Chicago, Illinois). Baseline data are reported as means ± standard deviation (continuous data) or percentages (categorical data), depending on the data level. The correlation between wrist, hip and lumbar BMD were evaluated using Pearson’s correlation. A p value of 0.05 or less was considered significant.
Results
In this study, 99 postmenopausal women with mean age of 57.06 ± 6.97 years with a mean menopause period of 9.13 ± 7.39 years were evaluated. Most patients (67%) were between 50- and 59-years old and 46.5% were in the first 10 years of postmenopause. Patients’ mean weight, height and BMI was 73.31 ± 10.23 kg, 156.82 ± 5.98 cm and 29.83 kg/m2, respectively. In these patients, mean wrist diameter was 5.2 ± 0.3 cm. DJD due to lumbosacral X-ray was reported in 84 cases (84.8%) including mild DJD in 45 (53.5%), moderate DJD in 33 (39.3%) and severe DJD in 6 (7.2%).
BMD findings are demonstrated in Table 1. Mean wrist BMD was lower than hip and lumbar BMD and no case had normal BMD values in the wrist. Considering BMD measurements of hip and lumbar spine together, there were 60 cases (60.36%) with osteoporosis. There was positive correlation between wrist BMD and hip (r = 0.468, p < 0.001) and lumbar BMDs (r = 0.322, p = 0.001), and between hip BMD and lumbar BMD (r = 0.258, p = 0.01).
Bone mineral density findings in different sites.
BMD, bone mineral density; SD, standard deviation.
Discussion
New pharmacologic treatments during recent years have encouraged physicians to screen patients at risk of fragile fractures by BMD measurement [Siris et al. 2014]. BMD evaluations are usually performed by DXA in hip and lumbar-spine sites (central DXA). Evaluating BMD of other sites, like the forearm, calcaneus and hand (peripheral DXA), is also recommended [Blake and Fogelman, 2007, 2010]. Peripheral DXA is an easy and inexpensive method for evaluating BMD in the body. However, these evaluations are shown to have poor correlation with central DXA, with correlation coefficients ranging betweenr = 0.5 and r = 0.65 [Lu et al. 2001]. Having no agreement between central and peripheral DXA is a barrier to recommending use of these methods [Faulkner et al. 1999; Lu et al. 2001].
Similarly, in our study there was poor correlation between wrist BMD as a peripheral DXA, with hip and lumbar BMD (r = 0.46 and r = 0.32, respectively); however, the correlation between wrist and hip was stronger than wrist and lumbar BMD. Similar to our findings, Rey and colleagues reported a significant correlation between wrist BMD, and hip and lumbar BMD [Rey et al. 1994]. Brownbill and Ilich observed that the hand (forearm) BMD has significant correlation with BMD of all skeletal sites [Brownbill and Ilich, 2002]. They concluded that wrist BMD evaluation in postmenopausal women is better than other sites in predicting fracture risk.
We also observed a weak correlation between lumbar and hip BMD, which was the lowest correlation measured in our study. Wrist BMD, in comparison with lumbar BMD, could predict hip osteoporosis; and in cases where hip BMD evaluation is not applicable due to some musculoskeletal burdens, for example, hip prosthesis, wrist BMD could be used for predicting BMD of the hip.
It is reported that at least half of patients tested by DXA will demonstrate T-score discordance between spine and total hip measurement sites [Moayyeri et al. 2005; Mounach et al. 2009; Younes et al. 2014]. There is one possible explanation for these results: in this study, DJD was reported in 84.8%, including 7.2% with severe DJD. The effect of osteophyte, a finding of severe DJD on BMD has been variably studied and it is reported that spine BMD is higher in vertebrates with osteophyte [Jones et al. 1995; Masud et al. 1993; Muraki et al. 2004; Reid et al. 1991]. Other studies have also evaluated the relationship between osteophyte and BMD at other sites, including hip [Miyakoshi et al. 2003; Pye et al. 2006], and recommended the same finding.
Osteophyte could not be differentiated from bone mineral of the vertebrae during evaluation of BMD, and it is possible to overestimate BMD at involved sites. Osteophyte could cause spine BMD misinterpretation; so spine BMD is not a proper marker for evaluating osteoporosis [Hart et al. 1994; Liu et al. 1997; Miyakoshi et al. 2003; Pye et al. 2006]. For this reason, in older women, lumbar BMD should be interpreted with caution. The higher rate of osteoporosis in the wrist in comparison with lumbar sites in our study also supports the possible effect of osteophyte and degenerative change in lumbar spine on lumbar BMD and its false-negative effects.
It is possible that increases in T-score values of lumbar spine due to degenerative changes reduces the osteoporosis prevalence of lumbar spine in comparison with other sites, and so lumbar BMD results should be interpreted with caution. Because of the high rate of lumbar DJD and the ability of wrist BMD to predict hip osteoporosis, BMD measurement of the wrist could be used for evaluation of osteoporosis in postmenopausal women. In conclusion, our results showed that wrist BMD has better accuracy than lumbar BMD in diagnosing osteoporosis in postmenopausal women.
Footnotes
Acknowledgements
The authors are indebted to Physical Medicine and Rehabilitation Research Center, Tabriz University of Medical Sciences, Iran, for its support.
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Conflict of interest statement
The authors declare that there is no conflict of interest.