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Diet and food intake play an important role in the development of osteoporosis. However, apart from calcium and vitamin D, how nutrients affect bone status is not fully understood. The purpose of this study was to determine cross-sectional and longitudinal associations between dietary intake and bone mineral density (BMD) in Japanese postmenopausal women. This 5-year cohort study included 600 community-dwelling women aged 55-74 years at baseline in 2005. Information on demographics, nutrition, and lifestyle was obtained through interviews, and nutritional and dietary intake was assessed using a validated food frequency questionnaire. BMD measurements were performed by dual energy X-ray absorptiometry. In 2010, 498 women underwent follow-up BMD examinations. Multiple linear regression analysis was performed to determine associations of predictor variables with BMD, adjusting for confounders. In cross-sectional analyses, coffee or black tea consumption was positively associated with lumbar spine (P = 0.004) and total hip (P = 0.003) BMD, and alcohol intake was positively associated with femoral neck (P = 0.005) and total hip (P = 0.001) BMD. In longitudinal analyses, vitamin K (P = 0.028) and natto (fermented soybeans) (P = 0.023) were positively associated with lumbar spine BMD, and meat or meat product consumption was inversely associated with total hip (P = 0.047) BMD. In conclusion, dietary factors other than calcium and vitamin D intake are predictors of bone mass and bone loss in Japanese postmenopausal women. In particular, natto intake is recommended for preventing postmenopausal bone loss on the basis of current evidence.

Current standard-dose calcium supplements (eg, 1000 mg/d) may increase the risk for cardiovascular events. Effectiveness of lower-dose supplements in preventing bone loss should thus be considered. This study aimed to assess whether calcium supplements of 500 or 250 mg/d effectively prevent bone loss in perimenopausal and postmenopausal Japanese women. We recruited 450 Japanese women between 50 and 75 years of age. They were randomly assigned to receive 500 mg of calcium (as calcium carbonate), 250 mg of calcium, or placebo daily. Medical examinations conducted three times over a 2-year follow-up period assessed bone mineral density (BMD) of the lumbar spine and femoral neck. One-factor repeated measures ANOVA was used for statistical tests. Subgroup analyses were also conducted. Average total daily calcium intake at baseline for the 418 subjects who underwent follow-up examinations was 493 mg/d. Intention-to-treat analysis showed less dramatic decreases in spinal BMD for the 500-mg/d calcium supplement group compared to the placebo group (1.2% difference over 2 years, p = 0.027). Per-protocol analysis (≥80% compliance) revealed that spinal BMD for the 500-mg/d and 250-mg/d calcium supplement groups decreased less than the placebo group (1.6%, p = 0.010 and 1.0%, p = 0.078, respectively), and that femoral neck BMD for the 500-mg/d calcium supplement group decreased less relative to the placebo group (1.0%, p = 0.077). A low-dose calcium supplement of 500 mg/d can effectively slow lumbar spine bone loss in perimenopausal and postmenopausal women with habitually low calcium intake, but its effect on the femoral neck is less certain. Calcium supplementation dosage should thus be reassessed. (Clinical Trials Registry number: UMIN000001176)., (Copyright © 2012 American Society for Bone and Mineral Research.)

Objective: The effect of physical activity on musculoskeletal health in older adults is not completely understood. The aim of this study was to determine the relationship between physical activity and 5-year changes in physical performance tests and bone mineral density (BMD) in postmenopausal women., Study Design: The design was a 5-year cohort study., Main Outcome Measures: Subjects were 507 women (55-74 years old) living in a rural community in Japan. Physical activity assessed included housework, farm work, and moderate leisure-time physical activity within the previous week. Measurements at baseline included handgrip strength, walking time (timed "Up & Go" test) and BMD of the femoral neck and vertebrae. Five-year changes in these measures (outcome variables) were compared among groups with different levels of physical activity by analysis of covariance., Results: Women who did not do housework performed worse in changes in handgrip strength (difference=2.22 kg, P=0.0201) and worse in changes in the walking time (difference=0.54 s, P=0.0072) than those who did housework alone. Women who spent at least 9h per week (median=24) doing farm work performed better in changes in handgrip strength (difference=0.28 kg, P=0.0334), but worse in changes in the walking time (difference=0.66 s, P<0.0001) than those who did not do farm work. However, leisure-time activity was not associated with changes in any outcome variable, and none of the physical activities predicted BMD changes., Conclusions: Engaging in housework and farm work are determinants of physical function in postmenopausal women, which may help them maintain independence in daily living., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Little has been understood about vitamin D status in relation to bone health in Asian women. The purpose of this study was to identify how the serum 25-hydroxyvitamin D (25[OH]D) concentration is associated with bone mass and bone metabolism. This cross-sectional, community-based epidemiologic study was conducted among 600 ambulatory postmenopausal women. The serum 25(OH)D concentration was measured with radioimmunoassay. Other blood biochemical measurements were intact parathyroid hormone and markers of bone turnover, including osteocalcin and type I collagen cross-linked N-telopeptides. Bone mineral density (BMD) of the lumbar spine and right femoral neck were measured with the dual-energy X-ray absorptiometry method using a QDR4500a. The mean serum 25(OH)D concentration was 55.6 nmol/L (SD 14.6). Serum 25(OH)D concentration was linearly associated with BMD of the femoral neck (R(2)=0.020, P=0.003), but not with BMD of the lumbar spine. Odds ratios (ORs) for low BMD (defined as t score < or =-2.5 SD) were calculated for strata defined by 25(OH)D concentration. The prevalence of low BMD of the lumbar spine was significantly higher in the 40- to 50-nmol/L 25(OH)D group (adjusted OR=3.0, 95% CI: 1.3-7.0) compared to the reference group (> or =70 nmol/L). Prevalence of low BMD for the femoral neck was significantly higher in the 30- to 40-nmol/L (adjusted OR=3.6, 95% CI: 1.1-12.1) and the 40- to 50-nmol/L (adjusted OR=7.6, 95% CI: 2.5-23.2) groups compared to the reference group (> or =70 nmol/L). The mean serum concentration of intact PTH was significantly higher in subjects with serum 25(OH)D <50 nmol/L compared to those with serum 25(OH)D > or =50 nmol/L. The present study suggests that higher serum 25(OH)D concentrations are associated with increased BMD of the femoral neck, and that a serum 25(OH)D concentration of at least 70 nmol/L is needed to obtain high BMD of the femoral neck, and that of at least 50 nmol/L is needed to achieve normal PTH levels and prevent low BMD in home-dwelling postmenopausal Japanese women.

Objective: In this 5‐year cohort study, we aimed to determine whether the intake of natto, a fermented soya bean food product, has an indirect effect on tooth loss incidence through BMD changes among postmenopausal women. Background: Evidence indicates (1) that natto has a beneficial effect on bone health and (2) that a decrease in bone mineral density (BMD) is associated with tooth loss. Methods: The study recruited 435 postmenopausal women (average age = 64.2 years). Natto intake (exposure) was assessed at baseline using a food frequency questionnaire. Lumbar spine BMD and number of teeth were measured at baseline and 5‐year follow‐up. BMD change (mediator) and the number of teeth lost (outcome) over time were calculated. The mediation model consisted of these 3 variables. Mediation analysis was performed to test the indirect effect of the natto intake measured through BMD change on tooth loss. Results: During the study, the mean number of teeth lost was 1.2 (standard deviation = 1.8), and the mean BMD decline was 2.5% (standard deviation = 7.1). After adjusting for potential confounders, increasing habitual natto intake was significantly indirectly associated with a lower incidence of tooth loss mediated by BMD change (incidence rate ratio of tooth loss among women with "≥1 pack/day" natto intake was 0.90 [95% confidence interval = 0.82‐0.99] compared to those with natto consumption of "rarely"). Conclusions: Dietary natto intake is significantly indirectly associated with a lower incidence of tooth loss among postmenopausal women, and systemic bone density could be a mediator of this association. [ABSTRACT FROM AUTHOR]

Objective: Low Ca intake is common among Japanese women, but its effect on bone metabolism has not been fully elucidated. The aim of the present study was to determine the relationship between Ca intake and serum markers of bone turnover in postmenopausal Japanese women. Design: A cross-sectional study. Setting: A community setting. Subjects: Subjects were 595 home-dwelling postmenopausal Japanese women. Ca intake was assessed by a validated FFQ. Serum type I collagen cross-linked N-telopeptides (NTX) and osteocalcin were measured as markers of bone turnover. The relationships between demographic characteristics, lifestyles, serum Ca, vitamin D and intact serum parathyroid hormone and bone turnover were also assessed. Results: The average age of the subjects was 64·5 (SD 5·8) years and the mean Ca intake was 527 (SD 160) mg/d. Ca intake was significantly associated with serum NTX (P50·0104), but not with serum osteocalcin. Mean serum NTX concentration in the lowest quartile of Ca intake (<417 mg/d) was significantly higher than in the fourth, referent quartile. Among these Japanese postmenopausal women, very low Ca intake (less than ~400 mg/d) was associated with increased bone resorption but not bone formation. Conclusions: Increased bone resorption may be one mechanism by which this Ca-depleted population normalizes bone metabolism and prevents osteoporosis. [ABSTRACT FROM AUTHOR]