Osteoporosis is a common disease with a strong genetic component, characterized by reduced bone mass and increased fracture risk. Current evidence suggests that the inheritance of bone mass is under polygenic control but the genes responsible are poorly defined. Type I collagen is the major protein of bone encoded by the COLIA1 and COLIA2 genes. While these are strong candidates for the genetic regulation of bone mass, no abnormality of either gene has so far been defined in osteoporosis. In this study, we describe a novel G-->T polymorphism in a regulatory region of COLIA1 at a recognition site for the transcription factor Sp1(7) that is significantly related to bone mass and osteoporotic fracture. G/T heterozygotes at the polymorphic Sp1 site (Ss) had significantly lower bone mineral density (BMD) than G/G homozygotes (SS) in two populations of British women and BMD was lower still in T/T homozygotes (ss). The unfavourable Ss and ss genotypes were over-represented in patients with severe osteoporosis and vertebral fractures (54%), as compared with controls (27%), equivalent to a relative risk of 2.97 (95% confidence interval 1.63-9.56) for vertebral fracture in individuals who carry the 's' allele. While the mechanisms that underlie this association remain to be defined, the COLIA1 Sp1 polymorphism appears to be an important marker for low bone mass and vertebral fracture, raising the possibility that genotyping at this site may be of value in identifying women who are at risk of osteoporosis.

These guidelines have been adopted by the British Nuclear Medicine Society.

Dual energy x ray absorptiometry (DXA) scans to measure bone mineral density (BMD) at the spine and hip have an important role in the evaluation of individuals at risk of osteoporosis, and in helping clinicians advise patients about the appropriate use of antifracture treatment. Compared with alternative bone densitometry techniques, hip and spine DXA examinations have a number of advantages that include a consensus that BMD results can be interpreted using the World Health Organization T-score definition of osteoporosis, a proven ability to predict fracture risk, proven effectiveness at targeting antifracture therapies, and the ability to monitor response to treatment. This review discusses the evidence for these and other clinical aspects of DXA scanning, including its role in the new WHO algorithm for treating patients on the basis of their individual fracture risk.

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Periprosthetic bone loss is a major cause of concern in patients undergoing total hip arthroplasty (THA). Further studies are required to identify the factors determining the pattern of bone remodelling following THA and obtain improvements in the design and durability of prostheses. In this study, we monitored periprosthetic bone loss around two different types of hydroxyapatite coated femoral implant over a 3-year period to evaluate their design and investigate the relationship with the preoperative bone mineral density (BMD) at the spine, hip and forearm. Sixty patients (35 F, 25 M, mean age 63 years, range 46-75 years) undergoing THA were randomised to either the Anatomic Benoist Girard (ABG) or Mallory-Head (MH) femoral stem. Preoperative dual-energy X-ray absorptiometry (DXA) scans were acquired of the posteroanterior (PA) and lateral lumbar spine, the contralateral hip and the non-dominant forearm. Postoperative DXA scans were performed to measure periprosthetic BMD at 10 days (treated as baseline), 6 weeks, and 3, 6, 12, 24 and 36 months after THA using a standard Gruen zone analysis. Results were expressed as the percentage change from baseline and the data examined for the differences in bone loss between the different Gruen zones, between the ABG and MH stems, and the relationship with preoperative BMD. A total of 50 patients (24 ABG, 26 MH) completed the study. Three months after THA there was a statistically significant BMD decrease in every Gruen zone that varied between 5.6% and 13.8% for the ABG prosthesis and between 3.8% and 8.7% for the MH prosthesis. Subsequently, in most zones BMD reached a plateau or showed a small recovery. However, BMD continued to fall in Gruen zones 1 and 7 in ABG patients and Gruen zone 1 in MH patients. Bone loss was less in every Gruen zone in MH patients compared with ABG with the largest difference (10%, P=0.018) in Gruen zone 7. Highly significant relationships were found between periprosthetic bone loss and preoperative BMD measured at the PA spine ( P<0.001), total hip ( P=0.004) and total distal radius ( P<0.001). This study showed differences between two different designs of hydroxyapatite-coated implant that confirmed that prosthesis design influences periprosthetic bone loss. The study also showed that patients' bone density measured at the spine, hip or forearm at the time of operation was a major factor influencing bone loss around the femoral stem.

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With the increasing number of quantitative ultrasound (QUS) devices in use worldwide it is important to develop strategies for the clinical use of QUS. The aims of this study were to examine the age-dependence of T-scores and the prevalence of osteoporosis using the World Health Organization Study Group criteria for diagnosing osteoporosis and to examine the T-score threshold that would be appropriate to identify women at risk of osteoporosis using QUS. Two groups of women were studied: (i) 420 healthy women aged 20-79 years with no known risk factors associated with osteoporosis; (ii) 97 postmenopausal women with vertebral fractures. All subjects had dual-energy X-ray absorptiometry (DXA) measurements of the spine and hip and QUS measurements on three calcaneal ultrasound devices (Hologic Sahara, Hologic UBA575+, Osteometer DTUone). A subgroup of 102 (76 on the DTUone) healthy women aged 20-40 years was used to estimate the young adult mean and SD for each QUS and DXA measurement parameter to calculate T-scores. The age-related decline in T-scores for QUS measurement parameters was half the rate observed for the bone mineral density (BMD) measurements. The average T-score for a woman aged 65 years was -1.2 for QUS measurements and -1.75 for the BMD measurements. When osteoporosis was defined by a T-score < or = -2.5 the prevalence of osteoporosis in healthy postmenopausal women was 17%, 16% and 12% for lumbar spine, femoral neck and total hip BMD respectively. When the same definition was used for QUS measurements the prevalence of osteoporosis ranged from 2% to 8% depending on which ultrasound device and measurement parameter was used. Four different approaches, based on DXA-equivalent prevalence rates of osteoporosis, were utilized to examine which T-score threshold would be appropriate for identifying postmenopausal women at risk of osteoporosis using QUS measurements. These ranged from -1.05 to -2.12 depending upon the approach used to estimate the threshold and on which QUS device the measurements were performed, but all were significantly lower than the threshold of -2.5 used for BMD measurements. In conclusion, the WHO threshold of T = -2.5 for diagnosing osteoporosis requires modification when using QUS to assess skeletal status. For the three QUS devices used in this study, a T-score threshold of -1.80 would result in the same percentage of postmenopausal women classified as osteoporotic as the WHO threshold for BMD measurements. Corresponding T-score thresholds for individual measurement parameters on the two commercially available devices were -1.61, -1.94 and -1.90 for Sahara BUA, SOS and estimated heel BMD respectively and -1.45 and -2.10 for DTU BUA and SOS respectively Additional studies are needed to determine suitable T-score thresholds for other commercial QUS devices.