Summary It has been reported that treatment with a pharmacological dose (45 mg/d) of menaquinone-4 (MK-4) prevents bone loss in postmenopausal women. However, it is not known whether supplementation with low dose MK-4 has beneficial effects on bone metabolism in healthy women. The aim of this study is to examine the effects of the supplementation of 1.5 mg/d MK-4 for 4 wk on bone and lipid metabolism in healthy postmenopausal Japanese women. The study was performed as a randomized double blind placebo-controlled trial. The participants aged 53-65 y were randomly assigned to 2 groups and supplemented with 1.5 mg/d of MK-4 or a placebo for 4 wk ( n ϭ 20 for each group). The most marked effects of MK-4 intake were observed on serum osteocalcin (OC) concentrations. Serum undercarboxylated OC (ucOC) concentration decreased, and the ␥ -carboxylated OC (GlaOC) and GlaOC/GlaOC ϩ ucOC ratio that indicates the degree of OC ␥ -carboxylation increased significantly at 2 and 4 wk compared with that at baseline in the MK-4 group. The serum ucOC and GlaOC concentrations in the MK-4 group were significantly different from those in the placebo group at 2 wk. These results suggest that supplementation with 1.5 mg/d MK-4 accelerated the degree of OC ␥ -carboxylation. The concentrations of serum lipids and other indices were not different between the groups at either intervention period. Thus, the additional intake of MK-4 might be beneficial in the maintenance of bone health in postmenopausal Japanese women.

Background:We conducted a survey to examine the difference in metacarpal bone mineral density (BMD) associated with the duration of walking and participation in habitual exercise in order to assess the benefits of walking for the prevention of bone loss in Japanese women. Methods:The subjects were 1873 healthy women (premenopausal, n = 1502; postmenopausal, n = 371), aged 18-72 years, who were screened for osteoporosis at health-care centers. They were classified into pre-(n = 1502), early post-(0-5 years since menopause, n = 195) and late post-menopausal (6-20 years since menopause, n = 176) phases. The metacarpal BMD was measured by computer-assisted X-ray densitometry. Subjects completed a questionnaire on lifestyle factors that included habitual exercise and daily walking time. To consider the factors of aging and physical characteristics, the BMD of all subjects was adjusted for age and height using a multiple non-linear model based on the data for premenopausal women.Results: ANOVA indicated significant differences in adjusted BMD (BMD adj ) in all menopausal phases according to walking duration and whether or not habitual exercise was engaged in. Premenopausal and early postmenopausal women who walked for over 30 min a day had a significantly greater BMD adj than those walking for less than 30 min (2.743 vs 2.684 mm thickness of an aluminum equivalent [mm Al]; and 2.711 vs 2.597 mm Al, respectively). Late postmenopausal women who walked for over 120 min had a significantly greater BMD adj than those walking under 30 min per day (2.746 vs 2.539 mm Al). Conclusion:These findings suggest that daily walks of more than 30 min also affect the metacarpal BMD, which is a non-weight bearing site, although walking over 120 min seems required to benefit late postmenopausal women. We conclude that such daily walks appeared to be beneficial in maintaining BMD in Japanese women.

Second metacarpal bone changed by menopause, nutrition and physical activity similar with other bone site presented in the previous studies.

The aim of this study was to clarify the factors affecting vertebral bone loss in healthy women classified according to menopausal condition. The subjects were 287 healthy Japanese women aged between 40 and 60 years living in an urban community. Lumbar spine bone mineral density was measured by dual energy X-ray absorptiometry twice at the baseline and at the end of a 5-year period. The subjects were divided into 3 groups according to menstrual status and time after menopause (pre-menopause : PRE, 0-3 years post-menopause : PERI, and 4 years or more post-menopause : POST), and the relationships between the rate of bone loss over 5 years and physical and lifestyle factors were examined among the 3 groups. These longitudinal data indicated that the factors affecting vertebral bone loss differed according to menopausal condition. It was suggested that lifestyle modification to prevent osteoporosis in middle-aged and older women should be considered according to menopausal condition. Key Words lumbar spine bone mineral density, dual energy X-ray absorptiometry (DXA), bone loss, lifestyle, menopause.

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