Susan M. Ott

Randomised trial of effect of alendronate on risk of fracture in women with existing vertebral fractures

BACKGROUND Previous studies have shown that alendronate can increase bone mineral density (BMD) and prevent radiographically defined (morphometric) vertebral fractures. The Fracture Intervention Trial aimed to investigate the effect of alendronate on the risk of morphometric as well as clinically evident fractures in postmenopausal women with low bone mass. METHODS Women aged 55-81 with low femoral-neck BMD were enrolled in two study groups based on presence or absence of an existing vertebral fracture. Results for women with at least one vertebral fracture at baseline are reported here. 2027 women were randomly assigned placebo (1005) or alendronate (1022) and followed up for 36 months. The dose of alendronate (initially 5 mg daily) was increased (to 10 mg daily) at 24 months, with maintenance of the double blind. Lateral spine radiography was done at baseline and at 24 and 36 months. New vertebral fractures, the primary endpoint, were defined by morphometry as a decrease of 20% (and at least 4 mm) in at least one vertebral height between the baseline and latest follow-up radiograph. Non-spine clinical fractures were confirmed by radiographic reports. New symptomatic vertebral fractures were based on self-report and confirmed by radiography. FINDINGS Follow-up radiographs were obtained for 1946 women (98% of surviving participants). 78 (8.0%) of women in the alendronate group had one or more new morphometric vertebral fractures compared with 145 (15.0%) in the placebo group (relative risk 0.53 [95% Cl 0.41-0.68]). For clinically apparent vertebral fractures, the corresponding numbers were 23 (2.3%) alendronate and 50 (5.0%) placebo (relative hazard 0.45 [0.27-0.72]). The risk of any clinical fracture, the main secondary endpoint, was lower in the alendronate than in the placebo group (139 [13.6%] vs 183 [18.2%]; relative hazard 0.72 [0.58-0.90]). The relative hazards for hip fracture and wrist fracture for alendronate versus placebo were 0.49 (0.23-0.99) and 0.52 (0.31-0.87). There was no significant difference between the groups in numbers of adverse experiences, including upper-gastrointestinal disorders. INTERPRETATION We conclude that among women with low bone mass and existing vertebral fractures, alendronate is well tolerated and substantially reduces the frequency of morphometric and clinical vertebral fractures, as well as other clinical fractures.

Standardized nomenclature, symbols, and units for bone histomorphometry: A 2012 update of the report of the ASBMR Histomorphometry Nomenclature Committee

Before publication of the original version of this report in 1987, practitioners of bone histomorphometry communicated with each other in a variety of arcane languages, which in general were unintelligible to those outside the field. The need for standardization of nomenclature had been recognized for many years,(1) during which there had been much talk but no action. To satisfy this need, B Lawrence Riggs (ASBMR President, 1985 to 1986) asked A Michael Parfitt to convene an ASBMR committee to develop a new and unified system of terminology, suitable for adoption by the Journal of Bone and Mineral Research (JBMR) as part of its Instructions to Authors. The resulting recommendations were published in 1987(2) and were quickly adopted not only by JBMR but also by all respected journals in the bone field. The recommendations improved markedly the ability of histomorphometrists to communicate with each other and with nonhistomorphometrists, leading to a broader understanding and appreciation of histomorphometric data. In 2012, 25 years after the development of the standardized nomenclature system, Thomas L Clemens (Editor in Chief of JBMR) felt that it was time to revise and update the recommendations. The original committee was reconvened by David W Dempster, who appointed one new member, Juliet E Compston. The original document was circulated to the committee members and was extensively revised according to their current recommendations. The key revisions include omission of terminology used before 1987, recommendations regarding the parameters and technical information that should be included in all histomorphometry articles, recommendations on how to handle dynamic parameters of bone formation in settings of low bone turnover, and updating of references.

Change in bone turnover and hip, non-spine, and vertebral fracture in alendronate-treated women: the fracture intervention trial.

We used data from the Fracture Intervention Trial to assess the relationship change in bone turnover after 1 year of alendronate or placebo treatment and subsequent hip, non‐spine, and spine fracture risk among 6186 postmenopausal women. In the alendronate group (n = 3105), greater reductions in one or more biochemical marker were associated with a lower risk of fracture.

Relationships between mandibular and skeletal bone in an osteoporotic population

This study attempted to determine relationships between bone mass in the mandible and skeletal bone mass in a group of 85 postmenopausal women with osteoporosis. Mandibular bone mass was determined by microdensitometry, cortical thickness at the gonion, the height of the alveolar ridge in subjects who were edentulous, and periodontal probings. Skeletal measures were made up of total body calcium, bone mass at the radius, and the two newer bone mass measures of dual photon and computed tomography of the vertebrae. The height of the edentulous ridge correlated with total body calcium and mandibular mass. Most of the edentulous patients had ridges that were extremely resorbed. Mandibular mass correlated with all skeletal measures.

Incidence of atypical nontraumatic diaphyseal fractures of the femur

Bisphosphonates reduce the rate of osteoporotic fractures in clinical trials and community practice. “Atypical” nontraumatic fractures of the diaphyseal (subtrochanteric or shaft) part of the femur have been observed in patients taking bisphosphonates. We calculated the incidence of these fractures within a defined population and examined the incidence rates according to duration of bisphosphonate use. We identified all femur fractures from January 1, 2007 until December 31, 2011 in 1,835,116 patients older than 45 years who were enrolled in the Healthy Bones Program at Kaiser Southern California, an integrated health care provider. Potential atypical fractures were identified by diagnostic or procedure codes and adjudicated by examination of radiographs. Bisphosphonate exposure was derived from internal pharmacy records. The results showed that 142 patients had atypical fractures; of these, 128 had bisphosphonate exposure. There was no significant correlation between duration of use (5.5 ± 3.4 years) and age (69.3 ± 8.6 years) or bone density (T‐score −2.1 ± 1.0). There were 188,814 patients who had used bisphosphonates. The age‐adjusted incidence rates for an atypical fracture were 1.78/100,000/year (95% confidence interval [CI], 1.5–2.0) with exposure from 0.1 to 1.9 years, and increased to 113.1/100,000/year (95% CI, 69.3–156.8) with exposure from 8 to 9.9 years. We conclude that the incidence of atypical fractures of the femur increases with longer duration of bisphosphonate use. The rate is much lower than the expected rate of devastating hip fractures in elderly osteoporotic patients. Patients at risk for osteoporotic fractures should not be discouraged from initiating bisphosphonates, because clinical trials have documented that these medicines can substantially reduce the incidence of typical hip fractures. The increased risk of atypical fractures should be taken into consideration when continuing bisphosphonates beyond 5 years.

Aluminum Is Associated with Low Bone Formation in Patients Receiving Chronic Parenteral Nutrition

Patients treated with chronic total parenteral nutrition may develop metabolic bone disease. We evaluated 22 bone biopsy specimens from 16 patients. Compared with those of age- and sex-matched normal controls, these specimens had significantly higher osteoid area and lower total bone area and bone formation rate, as measured by double tetracycline labels. Aluminum was found in specimens from the 14 patients receiving casein hydrolysate but not in the two receiving amino acids as their nitrogen source. The reduced bone formation correlated inversely with the logarithm of the aluminum level. Aluminum was localized to the surface of mineralized bone; tetracycline uptake was absent at those sites. These bone findings are similar to those from aluminum intoxicated patients on hemodialysis. Both groups also have low parathyroid hormone levels. Thus, aluminum appears to be an important pathogenic factor in the osteodystrophy of patients receiving dialysis or total parenteral nutrition.

Relationships between mandibular and skeletal bone in a population of normal women.

In this study, we measured mandibular bone mass and density and cortical thickness at gonion in 50 normal women between the ages of 20 and 90. The subjects showed neither radiographic nor metabolic evidence of osteoporosis. Comparisons (by age) were made between mandibular measurements. Mandibular measurements were also compared with measurements of bone mass in the spine and the wrist. Mandibular bone mass was not significantly affected with age but mandibular bone mass was significantly correlated with skeletal bone mass. Cortical thickness at gonion decreased with age.

Injectable hormone contraception and Bone density: Results from a prospective study

Background Depot medroxyprogesterone acetate (DMPA) injectable contraception may decrease bone density and increase the risk for osteoporosis in later life. Prospective data are scarce, especially of the effects of DMPA discontinuation on bone. Methods Between 1994 and 1999, we conducted a population-based prospective cohort study among women enrollees of a Washington State health maintenance organization. We enrolled 457 nonpregnant women, ages 18–39 years (183 DMPA users and 274 non-users). Bone density was measured by dual-energy x-ray absorptiometry every 6 months for 3 years. Results Bone density decreased notably among DMPA-exposed women at the spine (adjusted mean bone density was −0.0053 gm/cm2 for DMPA users compared with +0.0023 gm/cm2 for non-users for each 6-month interval) and total hip (−0.0060 compared with −0.0002 gm/cm2). This represents an annualized mean rate of change at the spine of −0.87% compared with +0.40% and, at the hip, −1.12% compared with −0.05%. Discontinuers of this method (N = 110) showed sizable increases in bone density over comparison women (for each 6-month interval, adjusted mean spine bone density was +0.0067 gm/cm2 compared with +0.0023 gm/cm2, respectively; adjusted mean hip bone density was +0.0035 compared with −0.0002 gm/cm2). Estimated annualized mean rates of change were +1.41% compared with +1.03% at the spine and +0.40% compared with −0.05% at the hip. After 30 months, mean bone density for discontinuers was similar to that of non-users. Conclusions In this study, DMPA use was strongly associated with bone density loss. Substantial postdiscontinuation recovery of bone provides evidence that the effects may be largely reversible.

Effect of Parathyroidectomy on Bone Aluminum Accumulation in Chronic Renal Failure

In some patients with chronic renal failure, bone mineralization becomes defective after parathyroidectomy for secondary hyperparathyroidism. Because aluminum deposition in bone is associated with impaired bone formation and osteomalacia, we retrospectively studied bone-biopsy specimens from patients on hemodialysis who were not exposed to dialysate contaminated with aluminum, to determine whether aluminum accumulation on bone surfaces was enhanced by parathyroidectomy. Serial biopsy specimens taken before and after parathyroidectomy revealed an increase in the rate of aluminum deposition on the surface of mineralized bone after parathyroidectomy in each of the six patients studied. The accelerated rate of aluminum accumulation could not be explained by changes in the oral aluminum intake. The mean rate of bone formation (+/- S.E.M.) before parathyroidectomy was higher in the six patients than in six control patients who did not undergo parathyroid surgery (586 +/- 147 vs. 237 +/- 85 micron2 per square millimeter per day; P less than 0.05). After parathyroidectomy, the rate of bone formation fell to levels below normal (148 +/- 32 vs. 311 +/- 29 micron2 per square millimeter per day; P less than 0.05) but was not significantly different from the rate in the control group (319 +/- 126 micron2 per square millimeter per day). We conclude that parathyroidectomy in patients with chronic renal failure is associated with enhanced aluminum deposition on the bone surface, possibly as a result of low bone formation. Patients with secondary hyperparathyroidism who may be candidates for parathyroidectomy should be evaluated for aluminum excess before surgery, so that treatment with aluminum chelation may be considered.

Bone mineral density in women using depot medroxyprogesterone acetate for contraception

OBJECTIVE To evaluate the possible effects of depot medroxyprogesterone acetate injectable contraception on bone mineral density in reproductive-age women. METHODS We conducted a population-based cross-sectional comparison of bone mineral density levels in women using depot medroxyprogesterone acetate contraception and in women of similar age not using this method. The study recruited 457 nonpregnant women aged 18-39 years who were enrollees of a Washington state health maintenance organization. One hundred eighty-three women were receiving injections and 274 were not. Bone mineral density at several anatomic sites (spine, femoral neck, greater trochanter, and whole body) was measured using dual-energy x-ray absorptiometry. Data on other factors potentially related to bone density were collected through questionnaire and examination. RESULTS Overall, age-adjusted mean bone density levels were lower for users of this method than for nonusers at all anatomic sites: The mean difference was 2.5% for the spine (P = .03) and 2.2% for the femoral neck (P = .12). Exposure to depot medroxyprogesterone acetate continued to be significantly (P < .01) associated with decreased bone density at the femoral neck, spine, and trochanter after multivariate adjustment for other risk factors related to bone density. Age-specific comparisons indicated that the major differences in bone density between users and nonusers occurred in the youngest age group (women 18-21 years); the mean femoral neck bone density was 10.5% lower (P < .01) for the exposed women, and differences were consistent (P < .01) across all anatomic sites. We also noted a significant dose-response relation between longer use of depot medroxyprogesterone acetate and decreased bone density levels in this age group (P < .01 for all sites). CONCLUSION These results provide evidence that contraception with depot medroxyprogesterone acetate, particularly long-term use, may adversely affect bone mineral density levels in young women aged 18-21 years. The implications for future bone health need further study.