Faculty Profiles - NAKAMURA Kazutoshi

Papers - NAKAMURA Kazutoshi

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Vitamin D status, bone mass, and bone metabolism in home-dwelling postmenopausal Japanese women: Yokogoshi Study Reviewed

Kazutoshi Nakamura, Naoko Tsugawa, Toshiko Saito, Miki Ishikawa, Yasuo Tsuchiya, Keiko Maruyama, Rieko Oshiki, Ryosaku Kobayashi, Mitsue Nashimoto, Akihiro Yoshihara, Reo Ozaki, Toshio Okano, Masaharu Yamamoto

BONE 42 ( 2 ) 271 - 277 2008.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

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 <= -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 (>= 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 (>= 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 >= 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. (c) 2007 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bone.2007.09.056

Age-related decrease in serum 25-hydroxyvitamin D concentrations in the frail elderly: a longitudinal study Reviewed

Kazutoshi Nakamura, Tomoko Nishiwaki, Kimiko Ueno, Masaharu Yamamoto

JOURNAL OF BONE AND MINERAL METABOLISM 25 ( 4 ) 232 - 236 2007.7

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER TOKYO

Several cross-sectional studies have demonstrated an age-related decrease in serum 25-hydroxyvitamin D [25(OH)D] concentrations. No prospective studies, however, have been conducted to examine this correlation to date. The objectives of this study were to measure age-related changes in serum 25(OH)D concentrations and to identify predictors of change in serum 25(OH)D concentrations in the frail elderly during a 2-year follow-up period. Eighty elderly subjects (48 women and 32 men) were selected from people utilizing the long-term care insurance system in a community in Japan. All subjects participated in both the baseline and follow-up (2 years later) medical examinations. Baseline measurements included age, height, body mass index, and weight. Additionally, levels of activities of daily living (Barthel index), grip strength, lifestyle, serum 25(OH)D, intact parathyroid hormone (PTH), albumin, total protein, and creatinine concentrations were also determined at baseline. The average age of the subjects was 82.1 years (SD, 8.8). The 2-year decrease in serum 25(OH)D concentrations was calculated to be 6 nmol/l. Multiple linear regression analyses found that the 2-year change (Delta) in the log-transformed 25(OH)D was associated with oalbumin (beta = 0.503, R-2 = 0.288, P < 0.0001), and Delta log-transformed intact PTH was associated with baseline creatinine (beta = 0.453, R-2 = 0.142, P = 0.0006) and Delta log-transformed 25(OH)D (beta = -0.512, R-2 = 0.103, P = 0.0037). In conclusion, serum 25(OH)D concentrations decreased in the 2-year follow-up. This information is useful for the maintenance of vitamin D status and prevention of vitamin D insufficiency in the frail elderly.

DOI： 10.1007/s00774-007-0755-y

Threshold value of serum 25-hydroxyvitamin D concentration in relation to elevated serum parathyroid hormone concentrations in elderly Japanese women Reviewed

Kazutoshi Nakamura, Mitsue Nashimoto, Yasuo Tsuchiya, Toshiko Saito, Tomoko Nishiwaki, Kimiko Ueno, Yoko Okuda, Rieko Oshiki, Masaharu Yamamoto

JOURNAL OF BONE AND MINERAL METABOLISM 24 ( 5 ) 395 - 400 2006.9

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER TOKYO

This study was designed to determine the threshold value for 25-hydroxyvitamin D [25(OH)D] concentration in relation to elevated serum parathyroid hormone (PTH) concentrations in elderly Japanese women. The subjects were 582 noninstitutionalized, ambulant women who lived in a community in Japan. Serum 25(OH)D concentrations were determined using the Nichols Advantage chemiluminescent assay, and serum intact PTH concentrations were determined with a two-site immunoradiometric assay. Demographic characteristics, calcium intake, and serum 1,25(OH)(2)D levels were also determined. The average age, body mass index (BMI), and calcium intake of the subjects were 74.5 years (SD 4.5), 23.3kg/m(2) (SD 3.4), and 579mg/day (SD 248), respectively. The serum log-transformed intact PTH concentration was significantly predicted by the serum 25(OH)D concentration (r = -0.147, P = 0.0004), but not by age, BMI, the serum log-transformed 1,25(OH)(2)D concentration, or the log-transformed calcium intake. Analysis of variance with Dunnett's multiple comparisons showed that mean serum intact PTH concentrations with serum 25(OH)D concentrations less than 30nmol/l (mean intact PTH = 5.89pmol/l, P < 0.0001) and in the range 30-39nmol/l (mean intact PTH = 4.54pmol/l, P = 0.0067) were significantly higher than mean intact PTH concentrations for serum 25(OH)D concentrations greater than 50nmol/l (mean intact PTH = 3.65pmol/l, the baseline level), but the mean serum intact PTH concentration for 25(OH)D concentrations in the range 40-49nmol/l (mean intact PTH = 3.70pmol/l, P = 0.9975) was not. We conclude that serum 25(OH)D for ambulant elderly Japanese women should be maintained at 40nmol/l or higher.

DOI： 10.1007/s00774-006-0699-7

Vitamin D insufficiency in Japanese populations: from the viewpoint of the prevention of osteoporosis Reviewed

K Nakamura

JOURNAL OF BONE AND MINERAL METABOLISM 24 ( 1 ) 1 - 6 2006.1

Language：English Publisher：SPRINGER TOKYO

Low levels of vitamin D nutrition (i.e., vitamin D insufficiency), which potentially cause osteoporosis, have been recognized as a common health problem for elderly people in European and North American countries, but there have been no studies on the prevalence of vitamin D insufficiency in Japan until recently. The aim of this article was to review descriptive features of serum 25-hydroxyvitamin D [25(OH)D] levels and vitamin D insufficiency in Japanese subjects. Reviewing 15 studies pertaining to vitamin D nutritional status recently published for various Japanese populations revealed that: (1) the prevalence of vitamin D insufficiency in active elderly people was as low as 5% or less; (2) the prevalence of vitamin D insufficiency was much higher (up to about 50%) in inactive elderly people than in active elderly people, depending on activities of daily living (ADL); (3) frequent fish consumption helps increase serum 25(OH)D concentrations, especially in winter; and (4) vitamin D nutrition in young women was poorer than people in middle and advanced ages, which may adversely affect bone metabolism. Future studies should focus on the effects of low vitamin D status on bone mass and fractures in Japanese subjects.

DOI： 10.1007/s00774-005-0637-0

Efficacy of optimization of vitamin D in preventing osteoporosis and osteoporotic fractures: A systematic review Reviewed

Kazutoshi Nakamura, Iki Masayuki

Environmental Health and Preventive Medicine 11 ( 4 ) 155 - 170 2006

Language：English

Increased intake or supplementation of vitamin D is often recommended for normal bone health
however, its preventive effect on osteoporosis has not been fully evaluated. The aim of this review is to gather evidence of the efficacy of the optimization of vitamin D nutrition in preventing osteoporosis and osteoporotic fractures. PubMed was used for searching the relevant literature using the MeSH terms "Bone Density (limited to "human", "female", and "English" literature)" or "Fractures (limited to "human", "age ≥45 years", and "English" literature)", and "Vitamin D". The searches yielded 19 randomized controlled trials (RCTs), nine cohort studies, 19 case-control studies, 19 cross-sectional studies, and one meta-analysis. We attempted to answer three questions: 1) does increased vitamin D intake prevent bone loss in peri- and postmenopausal women?, 2) does increased vitamin D intake prevent osteoporotic fractures in the elderly?, and 3) does increased vitamin D intake positively affect peak bone mass attainment in young women? The answer to questions 1 and 2 is that a vitamin D intake of 10-17.5 μg/day (400-700 IU/day) or more is effective in preventing bone loss in late postmenopausal women and an intake of 17.5-20 μg/day (700-800 IU/day) or more together with a calcium supplement reduces the risk of osteoporotic fractures. For question 3, some lines of evidence support the negative effect of low vitamin D nutrition on the attainment of peak bone mass in young women. Further studies are needed to clarify the effect of vitamin D in this age group.

DOI： 10.1265/ehpm.11.155

Vitamin D and prevention of osteoporosis: Japanese perspective Reviewed

Kazutoshi Nakamura

Environmental Health and Preventive Medicine 11 ( 6 ) 271 - 276 2006

Language：English

Vitamin D insufficiency, or a low vitamin D status, is a prevalent condition worldwide. However, there have been no studies addressing this public health issue until recently. In this review article, a summary of a series of studies conducted by the author and his colleagues to determine whether the vitamin D status of Japanese people is adequate and how their vitamin D status affects bone mass and bone metabolism is presented. The observational studies conducted by our group revealed that vitamin D insufficiency does not seem to be a serious problem among active elderly people, but that elderly people with a low level of activities of daily living (ADL) are at a very high risk of vitamin D insufficiency. In young adults, a high intact PTH concentration due to vitamin D insufficiency, which adversely affects their bone mass, is common, suggesting that vitamin D nutrition, as well as dietary calcium intake, should be improved. However, the effects of vitamin D insufficiency among elderly Japanese on bone metabolism, bone mass, and fractures have not been clarified, and should be studied further to determine whether specific preventive strategies, such as vitamin D supplementation, are required for this high-risk group. Intervention studies targeting Japanese populations are required to further address this issue.

DOI： 10.1265/ehpm.11.271

Serum 25-hydroxyvitamin D levels and activities of daily living in noninstitutionalized elderly Japanese requiring care Reviewed

K Nakamura, T Nishiwaki, K Ueno, M Yamamoto

JOURNAL OF BONE AND MINERAL METABOLISM 23 ( 6 ) 488 - 494 2005.11

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER TOKYO

To date, no study has investigated the nutritional status of vitamin D in frail elderly people living at home. The purposes of this study were to assess serum 25-hydroxyvitamin D ( 25[ OH] D) levels and associated factors in noninstitutionalized elderly people who had various levels of physical disability, and to propose an adequate vitamin D nutritional status for the elderly by interpreting the serum 25( OH) D levels in relation to serum parathyroid hormone ( PTH) levels in this population. Health examinations were conducted in the winter and summer of 2003. The subjects were 143 elderly people in the winter, and 120 elderly people in the summer, who all used the long- term care insurance system at home. Serum 25( OH) D concentrations were determined with a chemiluminescence proteinbinding assay, and serum intact PTH concentrations were determined with an immunoradiometric assay. The subjects' disease histories and lifestyle information were obtained through an interview. Activities of daily living (ADL) levels were evaluated using the Barthel index, and grip strength was measured with a digital hand dynamometer. Average serum 25( OH) D levels in the winter and summer were 54.2 nmol/l (SD 29.0) and 53.3 nmol/l ( SD 32.3), respectively, and intact PTH concentrations in the winter and summer were 4.2 pmol/ l ( SD 1.8) and 4.3 pmol/ l ( SD 1.8), respectively. The proportion of people who had a low 25( OH) D (< 30 nmol/l) and high intact PTH levels (> 6.9 pmol/l) were 15% - 20% and 8%, respectively. Significant predictors of low serum 25( OH) D concentrations were low ADL levels, female sex, and low fish consumption in both seasons. Serum 25( OH) D concentrations of less than 50 nmol/l were associated with elevated serum intact PTH concentrations. In conclusion, elderly people requiring care at home are at high risk of hypovitaminosis D, and their low serum 25( OH) D levels are mainly associated with low ADL levels. In addition, maintenance of serum 25( OH) D concentrations above 50 nmol/ l may prevent hypovitaminosis D-induced hyperparathyroidism.

DOI： 10.1007/s00774-005-0633-4

Nutrition, mild hyperparathyroidism, and bone mineral density in young Japanese women Reviewed

K Nakamura, K Ueno, T Nishiwaki, Y Okuda, T Saito, Y Tsuchiya, M Yamamoto

AMERICAN JOURNAL OF CLINICAL NUTRITION 82 ( 5 ) 1127 - 1133 2005.11

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC CLINICAL NUTRITION

Background: The adverse effects of poor nutrition on the bones of young Asian women have not been fully elucidated.
Objective: The purpose of this study was to investigate possible associations of vitamin D nutrition, calcium intake, and other nutrients with bone metabolism and bone mass in young Japanese women.
Design: The subjects were 108 female college students aged 19-25 y. Dietary nutrients were measured by using the duplicate sampling method on 3 weekdays. Serum 25-hydroxyvitamin D [25(OH)D], intact parathyroid hormone, and bone turnover markers were also measured. Bone mineral density (BMD) of the spine and femur was measured by dual-energy X-ray absorptiometry.
Results: The proportions of the subjects with low 25(OH)D (<30 nmol/L) and high intact parathyroid hormone (>= 6.9 pmol/L) concentrations were 32.4% and 15.7%, respectively. Serum 25(OH)D concentrations (P = 0.0265) and calcium intake (P = 0.0103) were inversely associated with serum intact parathyroid hormone. In addition to weight and physical activity, the presence of mild hyperparathyroidism was associated with a low BMD of the lumbar spine (P = 0.0062) and the femoral neck (P = 0.0250), and a low calcium intake was associated with a low BMD of the femoral neck (P 0.0044).
Conclusions: Low calcium intake (based on low BMD of the femoral neck only) and mild hyperparathyroidism (based on low BMD of both the femoral neck and lumbar spine), partly explained by low vitamin D nutrition and a low calcium intake, are important predictors of low BMD in young Japanese women. Effects of poor nutrition and mild hyperparathyroidism on bone peak bone mass in young women should be further investigated in longitudinal studies.

DOI： 10.1093/ajcn/82.5.1127

Intakes of calcium and other nutrients related to bone health in Japanese female college students: A study using the duplicate portion sampling method Reviewed

K Ueno, K Nakamura, T Nishiwaki, T Saito, Y Okuda, M Yamamoto

TOHOKU JOURNAL OF EXPERIMENTAL MEDICINE 206 ( 4 ) 319 - 326 2005.8

Language：English Publishing type：Research paper (scientific journal) Publisher：TOHOKU UNIV MEDICAL PRESS

UENO, K., NAKAMURA, K., NISHIWAKI, T., SAITO, T., OKUDA, Y. and YAMAMOTO, M. Intakes of Calcium and Other Nutrients Related to Bone Health in Japanese Female College Students: A Study Using the Duplicate Portion Sampling Method. Tohoku J. Exp. Med., 2005, 206 (4), 319-326 - The purposes of this study were to determine intakes of nutrients related to bone health, such as calcium (Ca), phosphorus (P), sodium (Na), potassium (K), and protein, in Japanese female college students, using the duplicate portion sampling method, and to identify possible lifestyle factors explaining their calcium intakes. Subjects were 106 Japanese female college students aged 19-23 years. All foods in the duplicate portions, as eaten by the subjects during a three-weekday period, were collected. The minerals and protein in the food samples were analyzed. Life-style information was obtained by interview. Levels of cognitive eating restraint (CER) were assessed by the Three-Factor Eating Inventory. Average intakes of dietary Ca, P, Na, K, and protein were 380 (SD 209) mg/day, 649 (SD 212) mg/day, 2,535 (SD 847) mg/day, 1,108 (SD 429) mg/day, and 41.7 (SD 12.6) g/day, respectively. Ca intake was significantly associated with the frequency of milk intake (R-2 = 0.278, p < 0.001), intake of other dairy products (R-2 = 0.338, p < 0.001), and meal skipping (R-2 = 0.161, p < 0.001), but not with CER score (p = 0.378). Female college students are at high risk for poor Ca nutrition. Low intake of nutrients relevant to bone health is considered to adversely affect bone metabolism in young women. bone health; dietary calcium; duplication sampling method; female college student; minerals. (c) 2005 Tohoku University Medical Press.

DOI： 10.1620/tjem.206.319

Health characteristics of elderly Japanese requiring care at home Reviewed

T Nishiwaki, K Nakamura, K Ueno, K Fujino, M Yamamoto

TOHOKU JOURNAL OF EXPERIMENTAL MEDICINE 205 ( 3 ) 231 - 239 2005.3

Language：English Publishing type：Research paper (scientific journal) Publisher：TOHOKU UNIV MEDICAL PRESS

The number of elderly subjects requiring care is rapidly increasing, however, their health status has not been well studied. The purposes of this study were to describe the health characteristics of the elderly at home who were using long-term care insurance, and to clarify factors that influence dependence for activities of daily living (ADL). The subjects were 194 elderly people living at home, who were approved for care. The items surveyed were the demographic characteristics, care level (or level of dependence for ADL), Barthel index, grip strength, thigh muscle volume, cognitive impairment using the mini-mental state examination (MMSE), depressed mood using the geriatric depression scale (GDS-15), and serum albumin and hemoglobin levels. The grip strength (p = 0.0001), thigh muscle volume (P = 0.0030), MMSE score (p = < 0.0001) and serum albumin level (p = < 0.0001) decreased, while the GDS-15 score (p = 0.0142) increased with deteriorating care levels. The proportion of subjects not requiring assistance for the items "bathing" and "stair-climbing" in the Barthel index was markedly low in the subjects belonging to the relatively low (mild) care levels. The logistic regression analysis showed that factors associated with dependence for "bathing" and "stair-climbing" were the use of day-services, male sex, decline of grip strength, and a high GDS-15 score. In conclusion, it is important to strengthen the muscles of the upper half of the body, and to correct depressed moods for maintaining levels of ADL in the elderly requiring care at home.

DOI： 10.1620/tjem.205.231

Weight gain in childhood and bone mass in female college students Reviewed

T Saito, K Nakamura, Y Okuda, M Nashimoto, N Yamamoto, M Yamamoto

JOURNAL OF BONE AND MINERAL METABOLISM 23 ( 1 ) 69 - 75 2005.1

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER TOKYO

The attainment of maximal peak bone mass early on in life is one of the most important strategies for the prevention of osteoporosis in women. The aim of this study was to clarify the correlation between gains in body size in all growth phases in childhood and adult bone mass in women. The subjects were 86 female first-year university students, aged 18-21 years. We measured the subjects' bone mineral content (BMC) and bone mineral density (BMD) at the lumbar spine and the left hip, including the femoral neck, with dual energy X-ray absorptiometry. Each subject was measured for current height and weight. Height and weight at birth, and at 1.5, and 3 years were obtained from each maternity record book, and those between 6 and 18 years were obtained from their school health records. Other information, including physical activity and calcium intake, was obtained through an interview. Bivariate analysis showed that weight gains during the periods from birth to 1.5 years and from 9 to 12 years significantly correlated with both BMC and BMD values at any site. The stepwise method of multiple regression analysis showed that a weight gain during the period from birth to 1.5 years was significantly associated with BMC at the lumbar spine (P=0.0001) and at the femoral neck (P=0.0290) and with BMD at the lumbar spine (P=0.0387). Birth weight was significantly associated with BMC at the lumbar spine (P=0.0474) and the total hip (P=0.0352), and weight gain during the period from 9 to 12 years was significantly associated with BMC at the femoral neck (P=0.0376). In conclusion, birth weight and weight gain in infancy are important determinants of bone mass in young women. Additionally, a girl's prepubertal growth spurt is likely to be a key phase for the acquisition of bone mass in relation to body weight. Our findings suggest that osteoporosis prevention programs may need to start very early in the life cycle.

DOI： 10.1007/s00774-004-0543-x

Dietary calcium, sodium, phosphorus, and protein and bone metabolism in elderly Japanese women: A pilot study using the duplicate portion sampling method Reviewed

K Nakamura, Y Hori, M Nashimoto, Y Okuda, H Miyazaki, Y Kasai, M Yamamoto

NUTRITION 20 ( 4 ) 340 - 345 2004.4

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

OBJECTIVES: Associations between dietary factors and bone metabolism in Asians have not been thoroughly investigated. The purpose of this study was to determine the effect of dietary intake of calcium (Ca), phosphorus (P), sodium (Na), and protein on bone metabolism in elderly Japanese women by the duplicate portion sampling method.
METHODS: The subjects were 43 healthy female volunteers (mean age, 68.3 y; standard deviation, 6.8). Dietary nutrients were directly determined by using a 24-h duplicate meal portion. Serum osteocalcin and bone alkaline phosphatase and urinary deoxypyridinoline (DPD) and type I collagen cross-linked N-telopeptides (NTX-I) were measured as markers of bone turnover. Hormones related to bone metabolism, including serum 25-hydroxyvitainin D-3, 1,25-dihydroxyvitamin D-3, and intact parathyroid hormone also were determined. Urinary parameters were corrected for urinary creatinine concentration.
RESULTS: The mean (standard deviation) daily dietary intakes of Ca, P, Na, and protein were 660 (195) mg, 996 (208) mg, 4080 (1142) mg, and 63.9 (15.5) g, respectively. Dietary Ca was negatively correlated with urinary DPD (r = -0.417, P = 0.005) and NTX-I (r = -0.324, P = 0.034), and dietary P was negatively correlated with urinary DPD (r = -0.307, P = 0.045). Multiple regression analysis showed that only dietary Ca was associated with urinary DPD and NTX-I. Dietary Ca intake was significantly associated with bone resorption markers, but no other dietary factors were associated with any of the biochemical markers.
CONCLUSION: The major factor having an adverse effect on the bone health of the elderly Japanese women is low Ca intake and not other dietary minerals or protein.

DOI： 10.1016/j.nut.2003.12.004

Nutritional covariates of dietary calcium in elderly Japanese women: Results of a study using the duplicate portion sampling method Reviewed

K Nakamura, Y Hori, M Nashimoto, Y Okuda, H Miyazaki, Y Kasai, M Yamamoto

NUTRITION 19 ( 11-12 ) 922 - 925 2003.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

OBJECTIVES: The purposes of this study were to determine the intake of nutrients related to bone health, including calcium (Ca), phosphorus (P), sodium (Na), potassium (K), protein, and vitamin D, in elderly Japanese women and to examine possible intercorrelations between Ca intake and other nutrients.
METHODS: Fifty-three elderly women in a rural community in Japan participated by supplying duplicate meat samples of everything they ate during a 24-h period. Dietary Ca, P, Na, K, protein, and vitamin D intakes were examined. The mean (standard deviation) age of the 53 women was 68.2 y (6.4 y).
RESULTS: The mean (standard deviation) intakes of dietary Ca, P, Na, K, protein, and vitamin D were 670 (219) mg/d, 1019 (267) mg/d, 4203 (1341) mg/d, 2752 (844) mg/d, 65.2 (18.3) g/d, and 9.90 (8,89) mug/d, respectively. Dietary Ca was significantly correlated with dietary P (r = 0.732, P < 0.0001), Na (r = 0.336, P = 0.0140), K (r = 0.571, P < 0.0001), and protein (r = 0.563, P < 0.0001), but not with vitamin D. After adjusting the data to reflect the total dry weight, dietary Ca was still correlated with P (r = 0.696, P < 0.0001), K (r = 0.423, P = 0.0018), and protein (r = 0.405, P = 0.0029).
CONCLUSIONS: The intake of dietary nutrients relevant to bone health in ambulatory Japanese elderly women was examined and documented. The potential confounding effects of these nutrients, especially P, K, and protein, should be taken into account when evaluating the effects of dietary Ca on bone health in observational studies. (C) Elsevier Inc. 2003.

DOI： 10.1016/S0899-9007(03)00181-3

Effects of dietary habits and CYP1A1 polymorphisms on blood dioxin concentrations in Japanese men. Reviewed International journal

Yasuo Tsuchiya, Satoshi Nakai, Kazutoshi Nakamura, Kunihiko Hayashi, Junko Nakanishi, Masaharu Yamamoto

Chemosphere 52 ( 1 ) 213 - 9 2003.7

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

The major source of dioxin impurities in Japan in the past was agrochemical formulations; more recently, it has been exhaust from waste incinerators. To examine the environmental and genetic factors that influence blood dioxin concentration, we investigated the relationship among dioxin concentrations, dietary habits and cytochorome P450 1A1 (CYP1A1) polymorphisms (MspI type and Ile-Val type) in Japanese fishermen and farmers, including also a group of office workers as controls. The mean dioxin concentrations in the fishermen, the farmers and the controls were 161369, 79079 and 100500 pg/g fat, respectively. The elevated dioxin concentration with polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and coplanar-PCBs found in the fishermen may be due to the frequent consumption of fish; no such relationship was found both in the farmers and the controls. We found that the concentrations of congeners found as impurities in certain chemicals such as those previously used in agriculture showed no significant differences among the three groups; we consider it unlikely that the farmers would be directly exposed to dioxins from such chemicals. Thus, it is probable that the primary route of dioxin exposure in the Japanese population is through the food chain via fish consumption, regardless of occupation. No meaningful relationship between blood dioxin concentration and CYP1A1 polymorphisms was found in this study, although there was a significant difference between the concentration of total non-ortho-PCBs in genotypes A and B. Further studies on more subjects, including those of genotype C, are needed to confirm the relationship between blood dioxin concentrations and MspI polymorphisms.

DOI： 10.1016/S0045-6535(03)00110-3

Correlates of bone mineral density in elderly women living in nursing homes for the disabled in Japan Reviewed

K Nakamura, M Nashimoto, S Matsuyama, M Hatakeyama, M Yamamoto

AGING CLINICAL AND EXPERIMENTAL RESEARCH 14 ( 6 ) 485 - 490 2002.12

Language：English Publishing type：Research paper (scientific journal) Publisher：EDITRICE KURTIS S R L

Background and aims: Characteristics of bone aging in the institutionalized elderly are not well known. The aim of this study was to determine the factors correlated with the forearm bone mineral density (BMD) in elderly women with disability. Methods: Of 175 female residents living in nursing homes for the disabled in Niigata, Japan, 119 agreed to participate and underwent medical examinations in 1999; 107 (age range, 66-100) met our inclusion criteria. We measured forearm BMD by dual-energy X-ray absorptiometry (DXA), and the serum concentrations of 25-hydroxyvitamin D-3, 1,25-dihydroxyvitamin D-3, intact parathyroid hormone, albumin, total protein, and creatinine. Body weight, score of activities of daily living, and history of femoral neck fractures were also recorded. Results: Forearm BMD decreased with age, and the regression equation was BMD=0.9035exp, (-0.0179Age) (R-2=0.170, p<0.0001). Multiple linear regression analysis revealed that only age (R-2=0.178, p<0.0001), and serum creatinine (R-2=0.153, p<0.0001) and albumin (R-2=0.051, p=0.005) concentrations were independently associated with log-BMD. Twenty-five of the 107 subjects had a history of femoral neck fracture, and only serum albumin concentration (p=0.031) was shown to be associated with fracture history. Conclusions: Forearm BMD was associated with age, serum creatinine and albumin, which may be useful parameters for assessing the bone health of elderly women with disability.

Fish as a major source of vitamin D in the Japanese diet Reviewed

K Nakamura, M Nashimoto, Y Okuda, T Ota, M Yamamoto

NUTRITION 18 ( 5 ) 415 - 416 2002.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

OBJECTIVES: We investigated the amount and sources of vitamin D in the Japanese diet by analyzing diet records collected over a 4-mo period.
METHODS: Dietary data for this study were provided by a nursing home in Niigata, Japan. Diet records, written by the nursing home's dietitian, for 122 consecutive days between September and December 1999, were used. The amount of food for an individual was weighed before cooking and recorded on the diet record. Vitamin D-containing foods, including fish, eggs, meat, and mushrooms, were selected from the diet records, and their vitamin D (vitamin D2 plus D3) per day was calculated by referring to the Standard Tables of Food Composition in Japan.
RESULTS: The overall average vitamin D intake per day was 7.10 mug (284 IU), which is about 70% of the recommended dietary allowance of 10 mug (400 IU). There were no significant differences in vitamin D values over the 4 mo (P = 0.822). Overall, the contribution of vitamin D from fish to total vitamin D intake was 90.7%, followed by mushrooms (4.4%), eggs (3.2%), and meat (1.7%).
CONCLUSIONS: Frequent fish intake appears to be an advisable health practice in terms of preventing vitamin D insufficiency in the elderly. (C)Elsevier Science Inc. 2002.

DOI： 10.1016/S0899-9007(02)00751-7

Hypovitaminosis D and hyperparathyroidism in physically inactive elderly Japanese living in nursing homes: Relationship with age, sunlight exposure and activities of daily living

M Nashimoto, K Nakamura, S Matsuyama, M Hatakeyama, M Yamamoto

AGING CLINICAL AND EXPERIMENTAL RESEARCH 14 ( 1 ) 5 - 12 2002.2

Language：English Publishing type：Research paper (scientific journal) Publisher：EDITRICE KURTIS S R L

Background and aims: The purposes of this study were to investigate the prevalences of hypovitaminosis D and hyperparathyroidism in physically inactive elderly people living in Japanese nursing homes and determine any correlations with demographic, environmental and/or life-style factors. Methods: We targeted 220 elderly people living in nursing homes for the physically disabled in Japan. Of these, 133 (women, 113; men, 20) subjects who agreed and met our inclusion criteria were studied. The average age of the subjects was 84.6 years (SD 8.2). Serum 25-hydroxyvitamin D-3(25[OH]D-3), intact parathyroid hormone (intact PTH), creatinine, and albumin concentrations were measured in each subject. Total hours of sunshine during the previous 5 weeks, activities of daily living (ADL) levels, and dietary vitamin D intake were also measured. ADL levels were evaluated using the Physical Self-Maintenance Scale (5-point scale). The examinations were performed between October and December, 1999. Results: The average concentrations of serum 25(OH)D-3 and intact PTH were 29.9 nmol/L (SD 13.1) and 5.04 pmol/L (SD 2.27), respectively. The prevalences of hypovitaminosis D (25[OH]D-3<30 nmol/L) and hyperparathyroidism (intact PTH>6.90 pmol/L) were 771133 (57.9%) and 21/133 (15.8%), respectively. Serum 25(OH)D-3 concentrations were positively associated with hours of sunshine (R-2=0.371, p<0.001) and serum albumin concentrations (R-2=0.086, p<0.001), but not with age (p=0.075) or total ADL score (p=0.527). A negative association between serum intact PTH and 25(OH)D-3 levels was found in subjects who were 80 years or older (p<0.001) but not in subjects under the age of 80 years. Conclusions: Hypovitaminosis D and hyperparathyroidism are commonly seen in elderly Japanese with low ADL levels. Hypovitaminosis D seems to adversely affect PTH levels, especially in the very elderly.

Low serum concentrations of 25-hydroxyvitamin D in young adult Japanese women: A cross sectional study

K Nakamura, M Nashimoto, S Matsuyama, M Yamamoto

NUTRITION 17 ( 11-12 ) 921 - 925 2001.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

OBJECTIVES: The vitamin D nutrition status of young adult women is unclear, but a recent preliminary report suggested that they may have vitamin D insufficiency. This study assessed the serum concentrations of 25-hydroxyvitamin D (25[OH]D), an index of vitamin D nutrition status, in young adult Japanese women in comparison with those in older women and investigated whether serum 25(OH)D concentrations are associated with other calcium-related hormones and bone mass.
METHODS: A cross sectional study of 77 healthy women, age 19 to 66 y, working in nursing homes in Japan was conducted in the winter of 1999 and 2000. The investigation included blood tests, forearm bone mass measurements, and a lifestyle questionnaire,
RESULTS: The mean serum 25(OH)D concentration in women younger than 30 y was 34.0 nmoL/L (standard deviation [SD] = 11.0) and significantly lower than that in women 30 y and older (50.0 nmol/L, SD = 14.4). The proportion of subjects younger than 30 y who had serum 25(OH)D concentrations less than 30 nmol/L was 42.1% and was significantly higher (P < 0.001) than the proportion of those 30 y and older (10.3%). There was a weak but significant linear association between serum 25(OH)D concentrations and forearm bone, mineral content (R-2 = 0.114, P = 0.0052) but not between serum 25(OH)D concentrations and bone mineral density. The association held after adjusting for body weight (R2 = 0.139, P = 0.0111). Serum intact parathyroid hormone concentrations were within the normal range and not associated with serum 25(OH)D concentrations.
CONCLUSIONS: Serum 25(OH)D concentrations in young adult Japanese women (< 30 y old) are lower than those of older adult women (30 to 66 y), and lower serum 25(OH)D concentrations are likely associated with lower forearm bone mineral content. (C) Elsevier Science Inc. 2001.

DOI： 10.1016/S0899-9007(01)00662-1

Prevalence of anorexia nervosa and bulimia nervosa in a geographically defined area in Japan Reviewed

Kazutoshi Nakamura, Masaharu Yamamoto, Osamu Yamazaki, Yoshiaki Kawashima, Kensuke Muto, Toshiyuki Someya, Koji Sakurai, Shinichi Nozoe

International Journal of Eating Disorders 28 ( 2 ) 173 - 180 2000.9

Language：English Publishing type：Research paper (scientific journal)

Objective: Little has been understood regarding the frequency of eating disorders in Japan. This study was designed to identify the prevalence of anorexia nervosa (AN) and bulimia nervosa (BN) in Japan. Method: We asked doctors in all of the relevant medical facilities (130 hospitals and 1,326 clinics) in Niigata Prefecture to report patients with DSM-IV-diagnosed eating disorders who appeared or were admitted between 20-24 October 1997. The response rate was 94.4%. Results: The estimated point prevalences of AN and BN were 4.79 and 1.02, respectively, per 100,000 females. Specifically for the age group of 15-29 years, the prevalence of AN was 17.10 and that of BN 5.79. Discussion: The prevalence of AN and BN in Japan is lower than that for European Caucasian populations. This result may be due to cultural and ethnic differences and/or it may be a transient phenomenon. (C) 2000 by John Wiley and Sons, Inc.

DOI： 10.1002/1098-108X(200009)28:2<173::AID-EAT6>3.0.CO;2-I

Serum 25-hydroxyvitamin D concentrations and related dietary factors in peri- and postmenopausal Japanese women

K Nakamura, M Nashimoto, Y Hori, M Yamamoto

AMERICAN JOURNAL OF CLINICAL NUTRITION 71 ( 5 ) 1161 - 1165 2000.5

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC CLINICAL NUTRITION

Background: Few studies of vitamin D nutrition in Asian populations have been conducted.
Objective: The objective was to assess 25-hydroxyvitamin D [25(OH)D] concentrations in healthy elderly Japanese women during the winter and to determine whether 25(OH)D concentrations are associated with lifestyle.
Design: We investigated 151 women aged 66.5 +/- 6.7 y ((x) over bar +/- SD) living in a rural community in February 1999. Serum 25(OH)D and intact parathyroid hormone were measured by using HPLC and an immunoradiometric assay, respectively. Information on lifestyle factors, including sunshine exposure and the consumption of vitamin D-rich foods, was also obtained through an interview.
Results: The mean (+/- SD) 25(OH)D concentration was 59.9 +/- 17.0 nmol/L. Vitamin D insufficiencies (<30 nmol/L) were found in 4.6% of the women, a value lower than that found in white populations. No correlation was found between age and 25(OH)D concentrations (r = 0.004, P = 0.957). The 25(OH)D concentration of subjects who consumed fish frequently (greater than or equal to 4 times/wk) was 10.1 nmol/L higher (P < 0.001) than that of subjects with a moderate consumption of fish (1-3 times/wk). Additionally, those who did not consume eggs had significantly lower 25(OH)D concentrations than did those who consumed eggs greater than or equal to 1 time/wk (P < 0.05).
Conclusions: The nutritional status of vitamin D in Japanese populations seems to be better than that in most Western populations. Frequent fish consumption is believed to help maintain adequate concentrations of serum 25(OH)D in elderly Japanese women during the winter.

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