[Objective assessment of walking in housebound elderly who are able to go out alone].

AIM: The aim of this study was to objectively assess the risk parameters associated with walking in housebound elderly. METHODS: The subjects were 622 community-dwelling elderly (210 men and 375 women: age 65-85) with independence in activities of daily living (ADL). We administered questionnaires pertaining to housebound factors and measured walking parameters, twice, in May 2008 and May 2009. Housebound status was defined as leaving the house no more than once a week, and non-housebound status as more than once every 2-3 days. We measured the following walking parameters: usual and maximum walking speed, timed up and go, obstacle-negotiating gait, stair-climbing, and number of daily steps. RESULTS: The overall prevalence of housebound status was 10.0% in men and 8.5% in women. No statistically significant differences were seen in the prevalence of housebound status between genders or age groups. In men, maximum walking speed, timed up and go, and daily steps were slower or less in housebound than in non-housebound subjects. In women, all walking parameters, except usual walking speed, were slower or less in housebound than in non-housebound subjects. Logistic regression analysis showed that obstacle-negotiating gait was a risk factor for men (odds ratio 2.49), and for women, all walking parameters, except walking at usual speed, were risk factors, with the highest odds ratio of 4.77 for obstacle-negotiating gait. A slower obstacle-negotiating gait was a risk factor for housebound status for both men and women. CONCLUSION: Compared with non-housebound subjects, housebound elderly with the ability to go out alone had a similar usual walking speed but a slower obstacle-negotiating gait.

Pump-Free Microfluidic Hemofiltration Device.

Hemofiltration removes water and small molecules from the blood via nanoporous filtering membranes. This paper discusses a pump-free hemofiltration device driven by the pressure difference between the artery and the vein. In the design of the filtering device, oncotic pressure needs to be taken into consideration. Transmembrane pressure (TMP) determines the amount and direction of hemofiltration, which is calculated by subtracting the oncotic pressure from the blood pressure. Blood pressure decreases as the channels progress from the inlet to the outlet, while oncotic pressure increases slightly since no protein is removed from the blood to the filtrate in hemofiltration. When TMP is negative, the filtrate returns to the blood, i.e., backfiltration takes place. A small region of the device with negative TMP would thus result in a small amount of or even zero filtrates. First, we investigated this phenomenon using in vitro experiments. We then designed a hemofiltration system taking backfiltration into consideration. We divided the device into two parts. In the first part, the device has channels for the blood and filtrate with a nanoporous membrane. In the second part, the device does not have channels for filtration. This design ensures TMP is always positive in the first part and prevents backfiltration. The concept was verified using in vitro experiments and ex vivo experiments in beagle dogs. Given the simplicity of the device without pumps or electrical components, the proposed pump-free hemofiltration device may prove useful for either implantable or wearable hemofiltration.

[Aging changes in muscle mass of Japanese].

AIM: The purpose of this study is To examine the influence of age on muscle mass in a Japanese population for health promotion. METHODS: Subjects were 4,003 community-dwelling Japanese men and women. We employed four-frequency bioelectrical impedance analysis to estimate upper and lower limbs, trunk and whole body muscle mass. RESULTS: Men showed significantly more muscle mass in all parts of the body compared to women. There was a curvilinear relationship between age and muscle mass in both men and women. For all parts of the body, the slope of the regression line between age and muscle mass was greater in men than women. The changes in muscle mass with advancing age were different in each part of the body. In the upper limbs, there was little change with advancing age in both men and women. In the lower limbs, the decrease in muscle mass began after two decades, with the reduction in this muscle mass the greatest of all parts of the body with advancing age. In the trunk, the slope of the regression line increased from the second to the fifth decade, after which the slope decreased. CONCLUSIONS: These findings indicated that lower limb muscle mass was the first to begin to decrease and also showed the greatest decrease. For health promotion, it was seen as important to maintain muscle mass from at least middle age, with particular emphasis on the lower limbs.

[Utility of color-changeable chewing gum to evaluate masticatory ability in community-dwelling elderly persons].

PURPOSE: The masticatory ability of community-dwelling elderly persons is often evaluated using subjective questionnaires. However, an objective evaluation would clearly be beneficial so that problems can be adequately addressed. The purpose of this study was to determine the utility of color-changeable chewing gum to evaluate masticatory ability in community-dwelling elderly persons. METHODS: We analyzed the reliability of the chewing gum for assessment of masticatory ability in 5 individuals who were examined on 5 occasions at 2 hour intervals. We also analyzed the validity of color-change of the chewing gum for assessment of masticatory ability by means of a four-part examination of 210 community-dwelling elderly persons. The four parts were as follows: evaluation of masticatory ability with the gum, determination of the number of residual teeth, measurement of maximum bite force, and a questionnaire in which participants were asked to assess their own masticatory ability. Color changes in the gum after chewing were measured with a color-reader and quantified with the a* color space defined by the Commission Internationale de l'Eclairage. A higher a* value indicates a higher degree of mastication. RESULTS: With respect to reliability, the coefficient of variation for the a* of the color-changeable chewing gum was 2.15-3.75%. There were no significant a* value differences between men and women in any age group. Decrease with age was significantly only in women. With respect to validity, the a* value of the color-changeable chewing gum had a significant positive correlation with the number of residual teeth and maximum bite force in both men and women. In addition, men and women who reported good masticatory ability in response to the questionnaire had significantly high a* values. CONCLUSION: We found the use of color-changeable chewing gum to be a highly reliable and valid method for evaluating masticatory ability. Our results indicate that this method could be useful for monitoring masticatory ability in the community-dwelling elderly.

[Relationship between occlusal force and preventive factors for disability among community-dwelling elderly persons].

AIM: Mastication ability is well documented as a risk factor for disability in the elderly. The aim of the present study was to assess occlusal force, one index of mastication ability, among elderly Japanese and clarify related factors through both physical measurements and questionnaires. METHODS: Subjects were 372 community-dwelling persons (101 men, 271 women) aged 60-87 years and registered at five welfare centers for the aged in a metropolitan suburb. Occlusal force was measured with dental prescale/occluzer system. Physical measurements and questionnaires were performed to explore related factors. RESULTS: Occlusal force was 502.4 N in men and 372.2 N in women. In the 60-69 and 70-79 age stratifications, men had significantly higher occlusal force than women. Occlusal force correlated significantly with age (r=-0.2, p<0.01), and number of residual teeth (r=0.6, p<0.01). After adjustment for age and the number of residual teeth, occlusal force had positive partial correlation with handgrip strength in men, and positive partial correlations with usual walking speed and body muscle mass, and negative partial correlation with timed up and go in women. From the questionnaire, high occlusal force was significantly associated with "can bite hard food" in both men and women; and with lifestyle factors ("walking regularly", "no smoking", and "alcohol consumption") in men; and with psychological factors ("intraoral satisfaction" and "no depression tendency") and physical factors ("can walk 1-km" and "can go out alone to distant places") in women. CONCLUSION: Occlusal force was related to physical fitness, ability of movement, and lifestyle.

[A cross-sectional study on the relationship between the Trail Making Test and mobility-related functions in community-dwelling elderly].

AIM: The Trail Making Test (TMT) has been studied in western countries as an indicator of executive function, but there are few data on the TMT in Japan. This study was conducted to assess the characteristics of TMT and to explore the effect of TMT on physical function among community-dwelling elderly Japanese to promote health in the aged. METHODS: Subjects were 175 individuals aged>or=65 years (57 men and 118 women). The TMT test which consists of two parts (part A and part B)was performed. 8 physical function items such as indicators of functional decline (usual walking speed, timed up-and-go (TUG), one-leg standing balance, and handgrip strength), and indicators of mobility (maximum walking speed, TUG with cup, stair-climbing, obstacle-negotiating gait) were measured. For this analysis, we used a difference score defined as TMT calculated as the difference between times (part B-part A=TMT). Data were analyzed by sex respectively. RESULTS: The median TMT value was 58.61 seconds in men and 65.67 seconds in women. TMT value increased with age and there was no difference between men and women in absolute values. multinomial logistic regression analysis showed that poor TMT was related to low tertiles of TUG, handgrip strength, MWS, TUG with cup, stair-climbing and obstacle-negotiating gait, and to intermediate tertile of MWS with adjustment for age and sex. CONCLUSION: TMT was significantly associated with mobility-related functions, suggesting that TMT, as the indicator of executive function, should be considered to be included in the test batteries for evaluating older people.

Dynamic MRI of solitary pulmonary nodules: comparison of enhancement patterns of malignant and benign small peripheral lung lesions.

OBJECTIVE: The purpose of this study was to compare the dynamic contrast-enhanced MRI enhancement characteristics of malignant and benign solitary pulmonary nodules. MATERIALS AND METHODS: The characteristics of 202 solitary pulmonary nodules (diameter, 1-3 cm; 144 cases of primary lung cancer, 31 cases of focal organizing pneumonia, 15 tuberculomas, 12 hamartomas) were reviewed retrospectively. In all cases dynamic MR images were obtained before and 1, 2, 3, 4, 5, 6, and 8 minutes after bolus injection of gadopentetate dimeglumine. Maximum enhancement ratio, time at maximum enhancement ratio, slope of time-enhancement ratio curves, and washout ratio were assessed. Statistical analyses were performed with the Kruskal-Wallis test with Bonferroni correction, chi-square test, and receiver operating characteristic curves. RESULTS: For 122 (85%) of 144 primary lung cancers, time at maximum enhancement ratio was 4 minutes or less. For all tuberculomas and hamartomas, time at maximum enhancement ratio was greater than 4 minutes or gradual enhancement occurred without a peak time (p < 0.0001). Lung cancers had different maximum enhancement ratios and slopes than benign lesions (all p < 0.005). With 110% or lower maximum enhancement ratio as a cutoff value, the positive predictive value for malignancy was 92%; sensitivity, 63%; and specificity, 74%. With 13.5%/min or greater slope as a cutoff value, sensitivity, specificity, positive predictive value, and negative predictive value for malignancy were 94%, 96%, 99%, and 74%, respectively. CONCLUSION: Dynamic contrast-enhanced MRI is helpful in differentiating benign from malignant solitary pulmonary nodules. Absence of significant enhancement is a strong predictor that a lesion is benign.

Factors associated with good self-rated health of non-disabled elderly living alone in Japan: a cross-sectional study.

BACKGROUND: Self-rated health (SRH) is reported as a reliable predictor of disability and mortality in the aged population and has been studied worldwide to enhance the quality of life of the elderly. Nowadays, the elderly living alone, a particular population at great risk of suffering physical and mental health problems, is increasing rapidly in Japan and could potentially make up the majority of the aged population. However, few data are available pertaining to SRH of this population. Given the fact that sufficient healthcare is provided to the disabled elderly whereas there is little support for non-disabled elderly, we designed this population-based survey to investigate SRH of non-disabled elderly living alone and to identify the factors associated with good SRH with the purpose of aiding health promotion for the elderly. METHODS: A cross-sectional study was conducted in a metropolitan suburb in Japan. Questionnaires pertaining to SRH and physical conditions, lifestyle factors, psychological status, and social activities, were distributed in October 2005 to individuals aged > or = 65 years and living alone. Response rate was 75.1%. Among these respondents, a total of 600 male and 2587 female respondents were identified as non-disabled elderly living alone and became our subjects. Multivariate logistic regression was used to identify the factors associated with good SRH and sex-specific effect was tested by stepwise logistic regression. RESULTS: Good SRH was reported by 69.8% of men and 73.8% of women. Multivariate logistic regression analysis showed that good SRH correlated with, in odds ratio sequence, "can go out alone to distant places", no depression, no weight loss, absence of self-rated chronic disease, good chewing ability, and good visual ability in men; whereas with "can go out alone to distant places", absence of self-rated chronic disease, no weight loss, no depression, no risk of falling, independent IADL, good chewing ability, good visual ability, and social integration (attend) in women. CONCLUSION: For the non-disabled elderly living alone, sex-appropriate support should be considered by health promotion systems from the view point of SRH. Overall, the ability to go out alone to distant places is crucial to SRH of both men and women.

Urinary fluoride reference values determined by a fluoride ion selective electrode.

As fluoride has a very short half-life in the body and the major route for fluoride excretion is via the kidney, human exposure is best measured in urine, where the concentration is expected to be highest. The urinary fluoride concentrations of 167 healthy Japanese adults were determined by means of a fluoride ion selective electrode. When the results were corrected for a specific gravity rho = 1.024 g cm-3, the histogram of urinary fluoride concentrations highly skewed toward low values with sharp peakedness (skewness = 1.56, kurtosis = 3.08). The normality of the log-transformed histogram (skewness = 0.12, kurtosis = 0.07) and the straight line on log-probability paper clearly showed a key feature of lognormal distribution of urinary fluoride. A geometric mean (GM) of 613.8 microg/l and 95% confidential interval (CI) of 241.0-1633.1 microg/l were established as reference values for urinary fluoride. The results presented in this study will be useful as guidelines for the biological monitoring of fluoride in normal subjects and individuals at risk of occupational or environmental fluoride exposure.

Venous hemangioma arising from the diaphragm: a case report of computed tomography and magnetic resonance imaging findings.

We report a rare case of diaphragmatic hemangioma with computed tomography and magnetic resonance imaging findings. A routine chest radiograph in a 75-year-old woman revealed a nodular opacity in the right lower lung field. Multidetector-row computed tomography revealed a well-circumscribed nodule arising from the diaphragm or pleura. Dynamic magnetic resonance imaging of the nodule showed a pattern of gradually increasing signal intensity. On the basis of the intraoperative and histopathologic findings, venous hemangioma arising from the diaphragm was diagnosed.

Urinary yttrium excretion and effects of yttrium chloride on renal function in rats.

Evaluation of yttrium exposure in biological samples has not been fully examined. To evaluate yttrium nephrotoxicity, yttrium chloride was orally administered to male Wistar rats and the urine volume (UV) and N-acetyl-beta-D-glucosaminidase (NAG) and creatinine excretion (Crt) were measured in 24-h urine samples. The urinary yttrium concentration and excretion rate were determined by inductively coupled plasma-argon emission spectrometry (ICP-AES). Large significant decreases of UV (>30%) and Crt (>10%) were observed at yttrium doses of 58.3-116.7 mg per rat, but no significant NAG changes was observed. This response pattern shows that a high yttrium dosage alters glomerular function rather than the proximal convoluted tubules. A urinary yttrium excretion rate of 0.216% and good dose-dependent urinary excretion (r=0.77) were confirmed. These results suggest that urinary yttrium is a suitable indicator of occupational and environmental exposure to this element, an increasingly important health issue because recent technological advances present significant potential risks of exposure to rare earth elements. We propose that the ICP-AES analytical method and animal experimental model described in this study will be a valuable tool for future research on the toxicology of rare earth elements.

Optic nerve head perfusion in normal eyes and eyes with glaucoma using optical coherence tomography-based microangiography.

BACKGROUND: To investigate the differences of perfusion in the optic nerve head (ONH) between normal and glaucomatous eyes using optical microangiography (OMAG) based optical coherence tomography (OCT) angiography technique. METHODS: One eye from each subject was scanned with a 68 kHz Cirrus 5000 HD-OCT-based OMAG prototype system centered at the ONH (Carl Zeiss Meditec Inc, Dublin, CA, USA). Microvascular images were generated from the OMAG dataset by detecting the differences in OCT signal between consecutive B-scans. The pre-laminar layer (preLC) was isolated by a semi-automatic segmentation program. En face OMAG images for preLC were generated using signals with highest blood flow signal intensity. ONH perfusion was quantified as flux, vessel area density, and normalized flux within the ONH. Standard t-tests were performed to analyze the ONH perfusion differences between normal and glaucomatous eyes. Linear regression models were constructed to analyze the correlation between ONH perfusion and other clinical measurements. RESULTS: Twenty normal and 21 glaucoma subjects were enrolled. Glaucomatous eyes had significantly lower ONH perfusion in preLC in all three perfusion metrics compared to normal eyes (P≤0.0003). Significant correlations between ONH perfusion and disease severity as well as structural changes were detected in glaucomatous eyes (P≤0.012). CONCLUSIONS: ONH perfusion detected by OMAG showed significant differences between glaucoma and normal controls and was significantly correlated with disease severity and structural defects in glaucomatous eyes. ONH perfusion measurement using OMAG may provide useful information for detection and monitoring of glaucoma.

Hydrocele of the canal of Nuck: a case report with magnetic resonance hydrography findings.

Hydrocele of the canal of Nuck, also called the "female hydrocele," is a rare developmental disorder in females. This entity is now believed to be more common now in comparison with previous reports; however, it is still an unfamiliar problem for physicians. The processus vaginalis accompanies the round ligament through the inguinal canal into the labium majus. This evagination of the parietal peritoneum forms the canal of Nuck in the female. The canal of Nuck normally loses its connection with the peritoneal cavity during the first year of life, but can result in a hernia or hydrocele when the connection of the canal of Nuck fails to close. Here, we present the case of a 43-year-old female who complained of swelling in the right inguinal region. Coronal and axial magnetic resonance imaging (MRI) revealed a cystic mass lesion with an irregular shape in the right inguinal region, and smaller cystic lesions extending alongside the right round ligament were also identified in the right side of the pelvic cavity. Magnetic resonance (MR) hydrography revealed the uninterrupted cystic lesion from the inguinal region to the pelvic cavity, with constrictions at the internal and external inguinal rings. These MR findings proved to be incredibly useful for surgical planning.

Comparison of the Biological Impacts of the Fluoride Compounds by Graphical Risk Visualization Map Technique.

Various fluoride compounds are widely used in industry. The present risk assessment study was conducted using a series of inorganic binary fluorides of the type XFn, where X(n) = Na(+), K(+), Li(+), Mg(2+), Ca(2+), Sr(2+), Ba(2+), Al(3+), Nd(3+), La(3+), Ce(3+), Sm(3+), Gd(3+), Y(3+), Yb(2+), and Zn(2+). The aqueous solutions of these salts were orally administrated to 16 experimental groups (one for each of the salts tested). The levels of fluoride, N-acetyl-ß-D-glucosaminidase in cumulative 24-h urine samples and creatinine clearance were measured to assess possible acute renal damages. The levels of fluoride, alanine aminotransferase, and aspartate aminotransferase were also determined in serum samples to assess possible acute hepatic damages. The results reveal that sodium fluoride (NaF), potassium fluoride (KF), and zinc fluoride tetrahydrate (ZnF2 (.)4H2O) can carry the fluoride ion into the bloodstream and that it is excreted via urine more readily than the other compounds tested. These fluorides were assigned the highest risk impact factor. Most of the rare earth fluorides are insoluble in water while those groups 2 and 13 of the periodic table are slightly soluble, so that they do not have a significant negative risk. These findings suggest that the biological impact of fluoride depends on the accompanying counter ion and its solubility. The risk map obtained in the present study shows that the graphical visualization map technique employed is a valuable new tool to assess the toxicological risk of chemical compounds.

Risk assessment visualization of rubidium compounds: comparison of renal and hepatic toxicities, in vivo.

Rubidium has been considered to be nontoxic. Its use includes thin film on glass deposition and as medical contrast medium. Recent technology innovations also involve the use of rubidium, but there is limited information about the biological effects of its various compounds. In the present risk assessment study, a series of rubidium compounds with different counter anions-acetate, bromide, carbonate, chloride, and fluoride-were orally administrated in a single dose to several groups of rats. Cumulative 24-h urine samples were obtained, and the levels of rubidium, fluoride, N-acetyl-ß-D-glucosaminidase and creatinine were measured to evaluate possible acute renal effects. Daily samples of serum were also obtained to determine the levels of aspartate and alanine aminotransferases to assess possible acute hepatic effects. Urinary rubidium excretion recovery of 8.0-10.5% shows that urine can be a useful diagnostic tool for rubidium exposure. The present results reveal that rubidium shows different biological effects depending on the counter anion. A pattern of large significant NAG leakage and elevation of ALT observed in rats treated with anhydrous rubidium fluoride indicates renal and hepatic toxicities that can be attributed to fluoride. The techniques reported in this study will be of help to assess the potential risks of toxicity of rubidium compounds with a variety of anions.

Urinary monitoring of exposure to yttrium, scandium, and europium in male Wistar rats.

On the assumption that rare earth elements (REEs) are nontoxic, they are being utilized as replacements of toxic heavy metals in novel technological applications. However, REEs are not entirely innocuous, and their impact on health is still uncertain. In the past decade, our laboratory has studied the urinary excretion of REEs in male Wistar rats given chlorides of europium, scandium, and yttrium solutions by one-shot intraperitoneal injection or oral dose. The present paper describes three experiments for the suitability and appropriateness of a method to use urine for biological monitoring of exposure to these REEs. The concentrations of REEs were determined in cumulative urine samples taken at 0-24 h by inductively coupled plasma atomic emission spectroscopy, showing that the urinary excretion of REEs is <2 %. Rare earth elements form colloidal conjugates in the bloodstream, which make high REEs accumulation in the reticuloendothelial system and glomeruli and low urinary excretion. The high sensitivity of inductively coupled plasma-argon emission spectrometry analytical methods, with detection limits of <2 µg/L, makes urine a comprehensive assessment tool that reflects REE exposure. The analytical method and animal experimental model described in this study will be of great importance and encourage further discussion for future studies.

Association between muscle mass and disability in performing instrumental activities of daily living (IADL) in community-dwelling elderly in Japan.

This study describes the association between low muscle mass and disability in performing IADL in elderly, community-dwelling Japanese subjects. Subjects were 1268 elderly, community-dwelling Japanese aged 65 years or older. Low muscle mass was defined by appendicular muscle mass index (AMI, weight [kg]/height [m(2)]), measured by bioelectrical impedance analysis (BIA). We classified "middle" AMI as a value 1-2 standard deviation (SD) below the young normal mean of AMI and "low" as more than 2 SD below the young normal mean. Examination of IADL was performed using the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC) questionnaire. In this study, 17.2% and 26.2% of elderly men and women, respectively, were classified as having low muscle mass. There was a significant association with age and the change from normal to middle to low muscle mass in both men and women. The prevalence of IADL disability also increased significantly as muscle mass decreased. After adjustment for age and BMI, low muscle mass was significantly associated with IADL disability in men and women. Furthermore, middle muscle mass was significantly associated with IADL disability in women. This study revealed that low muscle mass, defined as a value 2 SD below the mean of young adults, had a significant association with IADL disability in elderly Japanese. Interventions to prevent age-related losses in muscle mass may be an effective strategy to prevent IADL disability among the elderly.

Obstacle-negotiating gait and related physical measurement indicators for the community-dwelling elderly in Japan.

The aim of this study is to assess obstacle-negotiating gait (ONG) and explore its related physical factors. Subjects comprised 571 community-dwelling persons (195 men and 376 women) age>or=65 years and without cognitive impairment. ONG, timed up and go (TUG), and stair-climbing were measured and their relations were assessed. Walking ability (usual walking speed=UWS and daily walking steps=DWS), balance deficiency, and musculoskeletal function (handgrip strength and bone health) were examined objectively to explore ONG related physical factors. Logistic regression and general linear model analysis were performed with adjustment for age and body mass index (BMI). Time of ONG was 7.72s in men and 8.93s in women. Logistic regression analysis showed that the fast tertiles of ONG corresponding to the fast levels of TUG and stair-climbing had the highest odds ratio values. General linear model analysis showed that ONG was significantly associated with UWS and balance deficiency (no) in men, and with UWS, handgrip strength, DWS and balance deficiency (no) in women. Overall, ONG was considerably associated with falls screening tools and its determinants were also the main causes of falls. Training in ONG could be an attractive strategy for the prevention of falls among the elderly.

Association between the Trail Making Test and physical performance in elderly Japanese.

AIM: The Trail Making Test (TMT) is used in Western countries as an indicator of executive function, but there is little information regarding its use in Japan. Our previous initial study showed that the TMT was significantly associated with mobility-related functions among elderly Japanese living in the community and in this study, we increased the number of participants to clarify that result. METHODS: The TMT, comprised of two parts (part A and part B), was administered to 493 subjects aged 65 years or older (164 men, 329 women). Our assessment used the time difference (DeltaTMT) between parts B and A, and eight physical performance indicators: four of preventive care (usual walking speed, timed Up & Go [TUG], one-leg standing balance and handgrip strength) and four movement parameters (maximum walking speed, dual-task TUG, stair climbing and obstacle-negotiating gait). RESULTS: The median DeltaTMT score was 64.01 s for men and 65.56 s for women. The DeltaTMT score increased with age, and there was no difference between sexes. Multinomial logistic regression analysis showed that a poor DeltaTMT was related to low tertiles for all physical performances. It related to the intermediate tertile of TUG and maximum walking speed, dual-task TUG, stair climbing and obstacle-negotiating gait. CONCLUSION: The TMT reflects complex walking performance, so it can be a useful synthetic indicator for health programs promoting independence in elderly Japanese.

Assessment of the best gait parameter in relation to bone status in community-dwelling young-old and old-old women in Japan.

Even if physical exercise contributes to bone health of the elderly, intense activities have the potential to worsen the risk of osteoporosis. This fact and the inevitable decrease of mobility with age increase the likelihood that the mobility parameter that best benefits bone health differs with age. The aim of this study was to objectively assess the gait parameter that most strongly influences bone health of young-old and old-old women. Subjects comprised 200 community-dwelling elderly women (132 young-old, 68 old-old) registered at welfare centers for the aged. Bone status was examined in the right heel by quantitative ultrasound (QUS) and indicated as stiffness index (SI). Gait parameters including usual and maximum walking speed (UWS and MWS, respectively), daily walking steps (DWS), obstacle-negotiating gait, and stair-climbing were examined objectively. Other bone-related physical factors (body components, handgrip strength, and masticatory function) were measured and adjusted while performing assessment. After adjustment for covariates, multiple linear regression analysis showed that MWS had the strongest association with SI in young-old women and DWS had the strongest association with SI in old-old women. To prevent osteoporosis, brisk walking exercise and engaging in movement in everyday life, respectively, should be advocated for young-old women and old-old women in Japan.