Masataka Shiraki

Diagnostic criteria for primary osteoporosis: year 2012 revision

In 1995, the Japanese Society for Bone and Mineral Metabolism (now the Japanese Society for Bone and Mineral Research) established the Osteoporosis Diagnostic Criteria Review Committee. Following discussion held at the 13th scientific meeting of the Society in 1996, the Committee, with the consensus of its members, proposed diagnostic criteria for primary osteoporosis. The Committee revised those criteria in 1998 and again in 2000. The Japanese Society for Bone and Mineral Research and Japan Osteoporosis Society Joint Review Committee for the Revision of the Diagnostic Criteria for Primary Osteoporosis aimed at obtaining international consistency and made a revised edition based on the new findings in 2012.

Vitamin K2 (Menatetrenone) Effectively Prevents Fractures and Sustains Lumbar Bone Mineral Density in Osteoporosis

We attempted to investigate whether vitamin K2 (menatetrenone) treatment effectively prevents the incidence of new fractures in osteoporosis. A total of 241 osteoporotic patients were enrolled in a 24‐month randomized open label study. The control group (without treatment; n = 121) and the vitamin K2–treated group (n = 120), which received 45 mg/day orally vitamin K2, were followed for lumbar bone mineral density (LBMD; measured by dual‐energy X‐ray absorptiometry [DXA]) and occurrence of new clinical fractures. Serum level of Glu‐osteocalcin (Glu‐OC) and menaquinone‐4 levels were measured at the end of the follow‐up period. Serum level of OC and urinary excretion of deoxypyridinoline (DPD) were measured before and after the treatment. The background data of these two groups were identical. The incidence of clinical fractures during the 2 years of treatment in the control was higher than the vitamin K2–treated group (χ2 = 10.935; p = 0.0273). The percentages of change from the initial value of LBMD at 6, 12, and 24 months after the initiation of the study were −1.8 ± 0.6%, −2.4 ± 0.7%, and −3.3 ± 0.8% for the control group, and 1.4 ± 0.7%, −0.1 ± 0.6%, and −0.5 ± 1.0% for the vitamin K2–treated group, respectively. The changes in LBMD at each time point were significantly different between the control and the treated group (p = 0.0010 for 6 months, p = 0.0153 for 12 months, and p = 0.0339 for 24 months). The serum levels of Glu‐OC at the end of the observation period in the control and the treated group were 3.0 ± 0.3 ng/ml and 1.6 ± 0.1 ng/ml, respectively (p < 0.0001), while the serum level of OC measured by the conventional radioimmunoassay (RIA) showed a significant rise (42.4 ± 6.9% from the basal value) in the treated group at 24 months (18.2 ± 6.1% for the controls; p = 0.0081). There was no significant change in urinary DPD excretion in the treated group. These findings suggest that vitamin K2 treatment effectively prevents the occurrence of new fractures, although the vitamin K2–treated group failed to increase in LBMD. Furthermore, vitamin K2 treatment enhances γ‐carboxylation of the OC molecule.

Effects of 1 alpha-hydroxyvitamin D3 on lumbar bone mineral density and vertebral fractures in patients with postmenopausal osteoporosis.

The effects of 1α-hydroxyvitamin D3 [1α(OH)D3] on bone mineral density, fracture incidence, and bone metabolism were evaluated by a double-blind, placebo-controlled study. Eighty postmenopausal osteoporotic Japanese women (71.9±7.3 years, mean±SD) were randomly assigned to 1 μg of 1α(OH)D3 daily or inactive placebo for 1 year. All patients were given supplemental calcium (300 mg of elemental calcium daily). Lumbar (L2–L4) bone mineral density (BMD) determined by dual energy X-ray absorptiometry increased 0.65% with 1α(OH)D3 treatment and decreased 1.14% with placebo (P=0.037). BMD in both the femoral neck and Wards triangle did not yield any significant differences between the two groups, whereas trochanter BMD in the 1α(OH)D3-treated group increased 4.20% and decreased 2.37% with placebo (P=0.055). X-ray analysis demonstrated that new vertebral fractures occurred in two patients with 1α(OH)D3 and in seven patients with placebo. The vertebral fracture rate in the treated group was significantly less (75/1000 patient years) than in the control group (277/1000 patient years; P=0.029). Hypercalcemia (12.1 mg/100 ml) occurred in one patient receiving 1α(OH)D3; however, the serum calcium level in this patient promptly decreased to the reference range after cessation of the treatment. There were no significant changes in serum creatinine level in either group. A significant increase in urinary excretion of calcium was found but there was no significant change in urinary excretion of hydroxyproline in the treated group. The serum level of bone-derived alkaline phosphatase activity significantly decreased by−26±26 (mU/ml) after the treatment (P=0.003). These results indicate that 1α(OH)D3 treatment is effective for maintaining trabecular bone mass and prevents further vertebral fractures without any serious adverse effects in postmenopausal osteoporosis.

Association of bone mineral density with apolipoprotein E phenotype.

The phenotypes of apolipoprotein E (Apo E) and their relationship with the bone mineral density (BMD) were examined in 284 unrelated postmenopausal Japanese women aged 47–82 years (64.0 ± 1.0 years, mean ± SE). The Apo E phenotype was analyzed by the isoelectric focusing method, followed by immunoblotting. The relationship between the Apo E phenotype and the vitamin D receptor (VDR) gene or estrogen receptor (ER) gene genotypes was also studied in the same population. The Apo E phenotypic frequencies in our population were 9.9% for E3/2, 66.5% for E3/3, 1.8% for E4/2, 19.7% for E4/3, and 2.1% for E4/4. We classified these phenotypes into three categories: Apo E4−/− (E3/2 and E3/3, n = 217), Apo E4+/− (E4/3 and E4/2, n = 61), and Apo E4+/+ (E4/4, n = 6). The age, body weight, body height, and years since menopause were not significantly different among these three categories. The lumbar BMD values in these three groups were significantly different in the order of E4−/− (0.91 ± 0.01 g/cm2), E4+/− (0.85 ± 0.02 g/cm2), and E4+/+ (0.83 ± 0.06 g/cm2) (p = 0.031). The same trend was also observed for the Z score of the total BMD (p = 0.022). The serum level of intact osteocalcin in E4+/+ (15.2 ± 5.7 ng/ml) was higher than in E4−/− (7.7 ± 0.3 ng/ml) or E4+/− (7.7 ± 0.7 ng/ml) (p = 0.004 by analysis of variance). However, there were no other significant differences in the serum or urinary levels of bone turnover markers. Serum cholesterol in the E4+/+ group tended to be higher than in the other two groups (p = 0.05). There were no significant associations of the VDR and ER genotypes with the Apo E4 phenotype. A multivariate linear regression analysis revealed Apo E4 to be a significant, independent predictor of the Z score of the lumbar BMD. The effect of the Apo E4 allele on the Z score of the lumbar BMD (−0.493 ± 0.152) was not significantly different from that in the AAB of VDR (−0.616 ± 0.225) or PPxx of ER (−0.785 ± 0.314). In conclusion, the Apo E4 allele is associated with a low bone mass in postmenopausal Japanese.

Japanese fermented soybean food as the major determinant of the large geographic difference in circulating levels of vitamin K2: possible implications for hip-fracture risk.

Increasing evidence indicates a significant role for vitamin K in bone metabolism and osteoporosis. In this study, we found a large geographic difference in serum vitamin K2 (menaquinone-7; MK-7) levels in postmenopausal women. Serum MK-7 concentrations were 5.26 +/- 6.13 ng/mL (mean +/- SD) in Japanese women in Tokyo, 1.22 +/- 1.85 in Japanese women in Hiroshima, and 0.37 +/- 0.20 in British women. We investigated the effect of Japanese fermented soybean food, natto, on serum vitamin K levels. Natto contains a large amount of MK-7 and is eaten frequently in eastern (Tokyo) but seldom in western (Hiroshima) Japan. Serum concentrations of MK-7 were significantly higher in frequent natto eaters, and natto intake resulted in a marked, sustained increase in serum MK-7 concentration. We analyzed the relation between the regional difference in natto intake and fracture incidence. A statistically significant inverse correlation was found between incidence of hip fractures in women and natto consumption in each prefecture throughout Japan. These findings indicate that the large geographic difference in MK-7 levels may be ascribed, at least in part, to natto intake and suggest the possibility that higher MK-7 level resulting from natto consumption may contribute to the relatively lower fracture risk in Japanese women.

Estrogen receptor gene polymorphism and bone mineral density at the lumbar spine of pre- and postmenopausal women

In order to analyze the role of the estrogen receptor (ER) gene allelic polymorphisms on bone mineral density (BMD), 173 pre- and postmenopausal women were divided into four groups according to their menstrual status (group A: premenopausal women; group B: late premenopausal women; group C: postmenopausal women who had menopause for 5 years or less; and group D: postmenopausal women who had menopause for more than 5 years), and the relationship between ER gene polymorphism and lumbar spine BMD, the percent annual change in BMD and biochemical markers were studied. The restriction fragment length polymorphism (RFLPs) were represented as Xx (XbaI) and Pp (PvuII), with upper case and lower case letters signifying the absence or presence of restriction sites, respectively. In group A, the Xx genotype had significantly higher BMD (p < 0.01) than the xx genotype, but the difference was lost in groups B, C, and D. Because the percent annual change in BMD of group A was 0.052% and was not statistically different among genotypes, it is suggested that RFLP by Xba I is closely linked with peak bone mass that was attained during the subjects late thirties. In group B, serum N-region osteocalcin (N-OC) levels and the percent annual change in BMD showed a significantly larger increase than that of group A, indicating postmenopausal bone loss had commenced. Because the N-OC level of the Xx genotype was significantly higher than that of the xx genotype (p < 0.05), and the percent annual change in BMD of the Xx genotype showed a tendency to increase (p = 0.072), it is suggested that the high BMD of the Xx genotype is rapidly lost during menopausal transition. There were no significant relationships between RFLP and BMD in groups C and D, and between RFLP and BMD in groups C and D, and between RFLP by PvuII and BMD. The present study suggests that the Xx genotype is involved in accretion of BMD during young adulthood, but the effect was lost during menstrual transition.

Association of Methylenetetrahydrofolate Reductase (MTHFR) Polymorphism with Bone Mineral Density in Postmenopausal Japanese Women

Abstract. The pathogenesis of osteoporosis is controlled by genetic and environmental factors. Considering the high prevalence of osteoporosis in homocystinuria, abnormal homocysteine metabolism would contribute to the pathogenesis of osteoporosis. It is known that the polymorphism of methylenetetrahydrofolate reductase (MTHFR), the enzyme catalyzing the reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, correlates with hyperhomocysteinemia. In this study, we examined the association of this polymorphism with bone mineral density (BMD). BMD was measured by dual-energy X-ray absorptiometry (DXA) in 307 postmenopausal women. MTHFR A/V polymorphism was analyzed using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). We compared BMD, clinical characteristics, and bone metabolic markers among MTHFR groups (AA, AV, VV). The groups did not differ in terms of baseline data. The values of lumbar spine BMD and total body BMD were as follows: lumbar spine: AA, 0.91 ± 0.18, AV, 0.88 ± 0.16, VV, 0.84 ± 0.14 g/cm2; total body: AA, 0.97 ± 0.11, AV, 0.96 ± 0.11, VV, 0.93 ± 0.09 g/cm2. In the VV genotype, lumbar spine BMD values were significantly lower than those of the women with the AA genotype (P= 0.016) and total body BMD was significantly lower than those of the women with AA genotype (P= 0.03) and AV genotype (P= 0.04). This is the first report that suggests that the VV genotype of MTHFR is one of the genetic risk factors for low BMD.

Randomized Teriparatide [Human Parathyroid Hormone (PTH) 1–34] Once-Weekly Efficacy Research (TOWER) Trial for Examining the Reduction in New Vertebral Fractures in Subjects with Primary Osteoporosis and High Fracture Risk

CONTEXT Weekly teriparatide injection at a dose of 56.5 μg has been shown to increase bone mineral density. OBJECTIVE A phase 3 study was conducted to determine the efficacy of once-weekly teriparatide injection for reducing the incidence of vertebral fractures in patients with osteoporosis. DESIGN AND SETTING In this randomized, multicenter, double-blind, placebo-controlled trial conducted in Japan, the incidence of morphological vertebral fractures by radiographs was assessed. PATIENTS Subjects were 578 Japanese patients between the ages of 65 and 95 yr who had prevalent vertebral fracture. INTERVENTION Subjects were randomly assigned to receive once-weekly s.c. injections of teriparatide (56.5 μg) or placebo for 72 wk. MAIN OUTCOME MEASURE The primary endpoint was the incidence of new vertebral fracture. RESULTS Once-weekly injections of teriparatide reduced the risk of new vertebral fracture with a cumulative incidence of 3.1% in the teriparatide group, compared with 14.5% in the placebo group (P < 0.01), and a relative risk of 0.20 (95% confidence interval, 0.09 to 0.45). At 72 wk, teriparatide administration increased bone mineral density by 6.4, 3.0, and 2.3% at the lumbar spine, the total hip, and the femoral neck, respectively, compared with the placebo (P < 0.01). Adverse events (AE) and the dropout rates by AE were more frequently experienced in the teriparatide group, but AE were generally mild and tolerable. CONCLUSION Weekly s.c. administration of teriparatide at a dose of 56.5 μg may provide another option of anabolic treatments in patients with osteoporosis at higher fracture risk.

Guidelines for the use of biochemical markers of bone turnover in osteoporosis (2004)

A definition of osteoporosis was agreed upon at the 1993 consensus conference held in Hong Kong. It states that osteoporosis is “characterized by low bone mass and the microarchitectural deterioration of bony tissue, with a consequent increase in bone fragility and susceptibility to fracture.” This definition had been internationally used without revision until recently, when the definition was significantly changed at a National Institutes of Health (NIH) consensus conference in 2000 [1]. According to the consensus statement, osteoporosis is defined as “a skeletal disorder characterized by compromised bone strength predisposing a person to an increased risk of fracture.” Bone strength is determined by integrating bone mineral density (BMD) and bone quality. BMD is expressed as grams of mineral per area or volume, and, currently, BMD is defined by the individual peak bone density and the resorption rate from the peak. Bone quality is determined by characteristics of the bone matrix, such as microarchitecture, bone turnover, microdamage accumulation, the degree of calcification, and collagen [2,3]. Currently, it is thought that bone quality may not be clinically assessed by measures other than the determination of bone metabolism with biochemical markers of bone turnover. The change in definition may be the result of more recent findings [4], one that demonstrates bone fractures routinely occur despite patients having modest BMD levels, and another that has shown no significant reduction in the risk of a fracture occurring in patients taking one of the two standard medications, one that significantly increases BMD and the other that moderately increases it.

A new active vitamin D3 analog, eldecalcitol, prevents the risk of osteoporotic fractures--a randomized, active comparator, double-blind study.

BACKGROUND Eldecalcitol is an analog of 1,25-dihydroxyvitamin D(3) that improves bone mineral density; however, the effect of eldecalcitol on the risk of fractures is unclear. The objective of this study is to examine whether eldecalcitol is superior to alfacalcidol in preventing osteoporotic fractures. This trial is registered with ClinicalTrials.gov, number NCT00144456. METHODS AND RESULTS This 3 year randomized, double-blind, active comparator, superiority trial tested the efficacy of daily oral 0.75 μg eldecalcitol versus 1.0 μg alfacalcidol for prevention of osteoporotic fractures. 1054 osteoporotic patients 46 to 92 years old were randomly assigned 1:1 to receive eldecalcitol (n=528) or alfacalcidol (n=526). Patients were stratified by study site and serum 25-hydroxyvitamin D level. Patients with low serum 25-hydroxyvitamin D levels (<50 nmol/L) were supplemented with 400 IU/day vitamin D(3). Primary end point was incident vertebral fractures. Secondary end points included any non-vertebral fractures and change in bone mineral density and bone turnover markers. Compared with the alfacalcidol group, the incidence of vertebral fractures was lower in eldecalcitol group after 36 months of treatment (13.4 vs. 17.5%; hazard ratio, 0.74; predefined 90% confidence interval [CI], 0.56-0.97). Eldecalcitol reduced turnover markers and increased bone mineral density more strongly than alfacalcidol. Eldecalcitol reduced the incidence of three major non-vertebral fractures, which was due to a marked reduction in wrist fractures by a post-hoc analysis (1.1 vs. 3.6%; hazard ratio, 0.29; 95% CI, 0.11-0.77). Among the adverse events, the incidence of increase in serum and urinary calcium was higher in the eldecalcitol group, without any difference in glomerular filtration rate between the two groups. CONCLUSIONS Eldecalcitol is more efficacious than alfacalcidol in preventing vertebral and wrist fractures in osteoporotic patients with vitamin D sufficiency, with a safety profile similar to alfacalcidol.