Kozo Nakamura

National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Saitama, Japan

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Publications (367)1471.13 Total impact

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    ABSTRACT: We aimed to clarify the association between new indices in a locomotive syndrome risk test and decline in mobility. In the third survey of the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study, data on the indices were obtained from 1575 subjects (513 men, 1062 women) of the 1721 participants in mountainous and coastal areas. As outcome measures for decline in mobility, we used the five-times-sit-to-stand test (FTSST) and walking speed with cutoff values of 12 s and 0.8 m/s, respectively. We first estimated the prevalence of the indices in locomotive syndrome risk test stage 1, including two-step test score <1.3, difficulty with one-leg standing from a 40-cm-high seat in the stand-up test, and 25-question GLFS score ≥7, which were found to be 57.4, 40.6, and 22.6 %, respectively. Next, we investigated the prevalence of the indices in locomotive syndrome risk test stage 2, including two-step test score <1.1, difficulty with standing from a 20-cm-high seat using both legs in the stand-up test, and 25-question GLFS score ≥16, which were found to be 21.1, 7.9, and 10.6 %, respectively. Logistic regression analysis using slow FTSST time or slow walking speed as the objective factor, and presence or absence of indices as the independent factor, after adjusting for confounders, showed all three indices in both stages 1 and 2 were significantly and independently associated with immobility. Finally, we clarified the risk of immobility according to an increasing number of indices in both stages 1 and 2 and found that the odds ratio for both slow FTSST time and slow walking speed increased exponentially. We found that the three indices independently predicted immobility and that accumulation of indices increased the risk of immobility exponentially.
    Journal of Orthopaedic Science 06/2015; DOI:10.1007/s00776-015-0741-5 · 1.01 Impact Factor
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    ABSTRACT: Objective To determine whether 8-iso-prostaglandin F2α (8-iso-PGF2α) is a reliable biomarker of the accumulation of metabolic risks [e.g., overweight, hypertension, impaired glucose tolerance (IGT), and dyslipidemia].Methods This was a cross-sectional study of the baseline characteristics of a Japanese general population cohort study: Research on Osteoarthritis/Osteoporosis Against Disability (ROAD). Of 1,690 participants, 1,527 fulfilled all questionnaires and examinations. Free and conjugated urinary 8-iso-PGF2α levels and metabolic syndrome (MetS) components including blood pressure, HbA1c, total cholesterol, high-density lipoprotein cholesterol (HDL-C), and non-HDL-C were analyzed. The data were analyzed by ANCOVA, multiple regression analysis, and multinomial logistic analysis.Results8-iso-PGF2α was significantly associated with HbA1c and significantly inversely associated with total cholesterol and non-HDL-C. Notably, IGT with an HbA1c cut-off of 5.5% was significantly associated with 8-iso-PGF2α level in participants aged ≤50 years. Multinomial logistic regression analysis revealed 8-iso-PGF2α level was significantly associated with a greater number of MetS risks present; this association was stronger in younger participants. In participants aged ≥71 years, 8-iso-PGF2α was significantly associated with a greater number of MetS risks with higher IGT cut-offs.Conclusions Urinary 8-iso-PGF2α can be a reliable marker of IGT and the accumulation of MetS risks, especially in younger people.
    Obesity 06/2015; DOI:10.1002/oby.21130 · 4.39 Impact Factor
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    ABSTRACT: Motor dysfunction is a major reason why the elderly lose their independence in their daily lives. The concept of locomotive syndrome has been proposed to describe the risk of mobility dependence caused by various locomotive organ disorders. The preservation of locomotive organs is now socially important in the middle-aged and geriatric population. Therefore, it is important to establish a screening program to evaluate motor function and related quality of life in a wide range of ages. We propose a new set of pre-existing scales (the Two-Step test, Stand-Up test, and 25-question Geriatric Locomotive Function Scale) as screening tools to identify the population at high risk for locomotive syndrome. We performed a preliminary survey on 777 subjects who had no apparent disorders related to motor function. We also examined the reliability of the Two-Step test and Stand-Up test. We found that each scale did not show ceiling or floor effects in various age groups. Because the correlations between the three scales were significant but weak, we assume that each scale covers different aspects of mobility. The test-retest reliability was found to be satisfactory for the Two-Step test and the Stand-Up test. Our results suggest that our "Short Test Battery for Locomotive syndrome" is a feasible and reliable tool for screening the adult population as a preventative strategy for locomotive syndrome in a super-aged society.
    Journal of Orthopaedic Science 05/2015; DOI:10.1007/s00776-015-0737-1 · 1.01 Impact Factor
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    ABSTRACT: The objective of the present study was to clarify the association of joint space narrowing with knee pain in Japanese men and women using a large-scale population-based cohort of the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study. This study examined the association between minimum joint space width (mJSW) in the medial compartment and pain at the knee. mJSW was measured in the medial and lateral compartments of the knee using a knee OA computer-aided diagnosis system. From the 3,040 participants in the ROAD study, the present study analyzed 2,733 participants who completed the radiographic examinations and questionnaires regarding knee pain (975 men and 1,758 women; mean age, 69.9±11.2 years). Subjects with lateral knee OA were excluded. After adjustment for age and BMI, medial mJSW, as well as medial mJSW/lateral mJSW, was significantly associated with knee pain. Sex and BMI affected the association of medial mJSW with knee pain. The threshold of medial mJSW was approximately 3 mm in men and 2 mm in women, while that of medial mJSW/lateral mJSW was approximately 60% in both men and women. Body mass index was found to have a distinct effect on the association of mJSW with pain. The present cross-sectional study using a large-scale population from the ROAD study showed that joint space narrowing had a significant association with knee pain. The thresholds of joint space narrowing for knee pain were also established. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
    Osteoarthritis and Cartilage 01/2015; 23(6). DOI:10.1016/j.joca.2015.01.011 · 4.66 Impact Factor
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    ABSTRACT: Schwann cells are an important cell source for regenerative therapy for neural disorders. We investigated the role of the transcription factor sex determining region Y (SRY)-box 10 (SOX10) in the proliferation and myelination of Schwann cells. SOX10 is predominantly expressed in rat sciatic nerve-derived Schwann cells and is induced shortly after birth. Among transcription factors known to be important for the differentiation of Schwann cells, SOX10 potently transactivates the S100B promoter. In cultures of Schwann cells, overexpressing SOX10 dramatically induces S100B expression, while knocking down SOX10 with shRNA suppresses S100B expression. Here, we identify three core response elements of SOX10 in the S100B promoter and intron 1 with a putative SOX motif. Knockdown of either SOX10 or S100B enhances the proliferation of Schwann cells. In addition, using dissociated cultures of dorsal root ganglia, we demonstrate that suppressing S100B with shRNA impairs myelination of Schwann cells. These results suggest that the SOX10-S100B signaling axis critically regulates Schwann cell proliferation and myelination, and therefore is a putative therapeutic target for neuronal disorders.
    PLoS ONE 12/2014; 9(12):e115400. DOI:10.1371/journal.pone.0115400 · 3.53 Impact Factor
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    ABSTRACT: The inflammatory response following spinal cord injury (SCI) has both harmful and beneficial effects; however, it can be modulated for therapeutic benefit. Endotoxin/lipopolysaccharide (LPS) preconditioning, a well-established method for modifying the immune reaction, has been shown to attenuate damage induced by stroke and brain trauma in rodent models. Although such effects likely are conveyed by tissue-repairing functions of the inflammatory response, the mechanisms that control the effects have not yet been elucidated. The present study preconditioned C57BL6/J mice with 0.05 mg/kg of LPS 48 hr before inducing contusion SCI to investigate the effect of LPS preconditioning on the activation of macrophages/microglia. We found that LPS preconditioning promotes the polarization of M1/M2 macrophages/microglia toward an M2 phenotype in the injured spinal cord on quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemical analyses. Flow cytometric analyses reveal that LPS preconditioning facilitates M2 activation in resident microglia but not in infiltrating macrophages. Augmented M2 activation was accompanied by vascularization around the injured lesion, resulting in improvement in both tissue reorganization and functional recovery. Furthermore, we found that M2 activation induced by LPS preconditioning is regulated by interleukin-10 gene expression, which was preceded by the transcriptional activation of interferon regulatory factor (IRF)−3, as demonstrated by Western blotting and an IRF-3 binding assay. Altogether, our findings demonstrate that LPS preconditioning has a therapeutic effect on SCI through the modulation of M1/M2 polarization of resident microglia. The present study suggests that controlling M1/M2 polarization through endotoxin signal transduction could become a promising therapeutic strategy for various central nervous system diseases. © 2014 Wiley Periodicals, Inc.
    Journal of Neuroscience Research 12/2014; 92(12). DOI:10.1002/jnr.23448 · 2.73 Impact Factor
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    ABSTRACT: Disc degeneration (DD) reportedly causes low back pain (LBP) and is often observed concomitantly with endplate signal change (ESC) and/or Schmorl's node (SN) on magnetic resonance imaging (MRI). To examine the association between DD and LBP, considering ESC and/or SN presence, in a large population study. Cross-sectional, population-based study in 2 regions of Japan PARTICIPANT SAMPLE: Of 1011 possible participants, data from 975 participants (324 men, 651 women; mean age, 66.4 years; range, 21-97 years) were included. Prevalence of DD, ESC, and SN alone and in combination in the lumbar region, and the association of these prevalence levels with LBP. This study was funded by Japanese Grant-in-Aid for Scientific Research. There is no conflict of interest. Sagittal T2-weighted images were used to assess the intervertebral spaces between L1/2 and L5/S1. DD was classified using the Pfirrmann classification system (grade 4 and 5 indicated degeneration); ESC was defined as a diffuse high-signal change along either area of the endplate, and SN was defined as a small well-defined herniation pit with a surrounding wall of hypointense signal. Logistic regression analysis was used to determine the odds ratios (OR) and confidence intervals (CI) for LBP in the presence of radiographic changes in the lumbar region and at each lumbar intervertebral level, compared to patients without radiographic change, after adjusting for age, body mass index, and sex. The prevalence of lumbar structural findings was as follows: DD alone, 30.4%; ESC alone, 0.8%; SN alone, 1.5%; DD and ESC, 26.6%; DD and SN, 12.3%; and DD, ESC, and SN, 19.1%. These lumbar structural findings were significantly associated with LBP in the lumbar region overall, as follows: DD, ESC, and SN, OR 2.17, 95% CI 1.2-3.9; L1/2, OR 6.00, 95% CI 1.9-26.6; L4/5, OR 2.56, 95% CI 1.4-4.9; and L5/S1, OR 2.81, 95% CI, 1.1-2.3. The combination of DD and ESC was significantly associated with LBP as follows: L3/4, OR 2.43, 95% CI 1.5-4.0; L4/5, OR 1.82, 95% CI 1.2-2.8; L5/S1, OR 1.60, 95% CI 1.1-2.3. Our data suggest that DD alone is not associated with LBP. By contrast, the combination of DD and ESC was highly associated with LBP. Copyright © 2014 Elsevier Inc. All rights reserved.
    The spine journal: official journal of the North American Spine Society 11/2014; 15(4). DOI:10.1016/j.spinee.2014.11.012 · 2.80 Impact Factor
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    ABSTRACT: Objective. This study aimed to assess the mutual associations between musculoskeletal diseases (knee osteoarthritis [KOA], lumbar spondylosis [LS], osteoporosis [OP]) and metabolic syndrome components (obesity [OB], hypertension [HT], dyslipidemia [DL], impaired glucose tolerance [IGT]). Methods. Of the 1,690 participants (596 men, 1,094 women) at baseline, 1,384 individuals (81.9%; 466 men, 918 women) had complete data at the first follow-up in 2008. Logistic regression analysis included the occurrence or nonoccurrence of the musculoskeletal diseases or metabolic components as the outcome variable and the remaining musculoskeletal diseases and metabolic components at baseline as explanatory variables, adjusted for age, sex, residential region, smoking, and alcohol consumption. Results. The risk of KOA occurring increased significantly with HT (odds ratio [OR], 2.57; 95% confidence interval [CI], 1.22–5.42; p = 0.013) and IGT (OR, 1.99; 95%CI, 1.07–3.70; p = 0.029). The risk of OP occurring at the lumbar spine increased with OP at the femoral neck (OR, 4.21; 95%CI 1.46–12.1; p = 0.008), and vice versa (OR, 2.19; 95%CI, 1.01–479; p = 0.047). KOA increased the risk of HT (Kellgren–Lawrence [KL] grade = 0, 1 vs. KL = 2: OR, 1.84; 95%CI, 1.09–3.12; p = 0.024) and DL (KL = 0, 1 vs. KL ≥ 3: OR, 1.66; 95%CI, 1.05–2.61; p = 0.029) occurring. Reciprocal relationships existed between the presence of metabolic components and the occurrence of the other metabolic components. Conclusion. Mutual relationships existed between the occurrence and presence of musculoskeletal diseases, particularly KOA, and metabolic syndrome components.
    Modern Rheumatology 11/2014; 25(3). DOI:10.3109/14397595.2014.972607 · 2.21 Impact Factor
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    ABSTRACT: The population of elderly individuals who need nursing care is rapidly increasing in Japan. Locomotive syndrome involves a decrease in mobility due to locomotive organ dysfunction, and increases risk for dependency on nursing care service. Because gait speed and chair stand time are correlated with such risks, patients with locomotive syndrome are assessed using brief methods such as the two-step test, which involves dividing the maximum stride length by the height of the patient, and the stand-up test, which involves standing on one or both legs at different heights. One leg standing and squatting are recommended as beneficial locomotive home exercises. Locomotive syndrome has been recognized widely in Japan, and included in the National Health Promotion Movement (2013-2022).
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    ABSTRACT: The objective of the present longitudinal study was to clarify whether osteophytosis and joint space narrowing predict quality of life (QOL) decline using a longitudinal population-based cohort of the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study. The present study analyzed 1,525 participants who completed the radiographic examination at baseline and questionnaires regarding QOL at a 3-year follow-up (546 men and 979 women; mean age, 67.0 ± 11.0 years). This study examined the associations of osteophyte area (OPA) and minimum joint space width (mJSW) in the medial compartment of the knee at baseline with pain and physical functional disability measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). OPA and mJSW in the medial compartment of the knee were measured using a knee osteoarthritis (OA) computer-aided diagnosis system. Overall, OPA independently predicted physical functional disability after 3 years of follow-up. When analyzed in men and women separately, OPA, rather than mJSW, was an independent predictor for pain and physical functional disability after 3 years of follow-up in men. OPA, rather than mJSW, also predicted worsening of pain in men during the 3-year follow-up, whereas in women, mJSW, rather than OPA, predicted worsening of pain. In conclusion, the present longitudinal study using a large-scale population from the ROAD study found gender differences in the association of osteophytosis and joint space narrowing with pain and physical functional disability.
    Annals of the Rheumatic Diseases 05/2014; DOI:10.1007/s10067-014-2687-y · 9.27 Impact Factor
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    ABSTRACT: We investigated the incidence of disability and its risk factors in older Japanese adults to establish an evidence-based disability prevention strategy for this population. For this purpose, we used data from the Longitudinal Cohorts of Motor System Organ (LOCOMO) study, initiated in 2008 to integrate information from cohorts in nine communities across Japan: Tokyo (two regions), Wakayama (two regions), Hiroshima, Niigata, Mie, Akita, and Gunma prefectures. We examined the annual occurrence of disability from 8,454 individuals (2,705 men and 5,749 women) aged ≥65 years. The estimated incidence of disability was 3.58/100 person-years (p-y) (men: 3.17/100 p-y; women: 3.78/100 p-y). To determine factors associated with disability, Cox's proportional hazard model was used, with the occurrence of disability as an objective variable and age (+1 year), gender (vs. women), body build (0: normal/overweight range, BMI 18.5-27.5 kg/m(2); 1: emaciation, BMI <18.5 kg/m(2); 2: obesity, BMI >27.5 kg/m(2)), and regional differences (0: rural areas including Wakayama, Niigata, Mie, Akita, and Gunma vs. 1: urban areas including Tokyo and Hiroshima) as explanatory variables. Age, body build, and regional difference significantly influenced the occurrence of disability (age, +1 year: hazard ratio 1.13, 95 % confidence interval 1.12-1.15, p < 0.001; body build, vs. emaciation: 1.24, 1.01-1.53, p = 0.041; body build, vs. obesity: 1.36, 1.08-1.71, p = 0.009; residence, vs. living in rural areas: 1.59, 1.37-1.85, p < 0.001). We concluded that higher age, both emaciation and obesity, and living in rural areas would be risk factors for the occurrence of disability.
    Journal of Bone and Mineral Metabolism 04/2014; 33(2). DOI:10.1007/s00774-014-0573-y · 2.11 Impact Factor
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    ABSTRACT: A narrow cervical spinal canal (CSC) is a well-known risk factor for cervical myelopathy (CM). However, no epidemiologic data of CSC based on a population-based cohort are available. 1) To investigate the age-related differences in CSC diameters on plain radiographs, 2) To examine the associated MRI abnormalities including cervical cord compression and increased signal intensity (ISI) as well as the clinical CM with the narrow CSC Study Design/Setting: A cross-sectional study PARTICIPANT SAMPLE: Data were obtained from the base-line survey of Wakayama Spine Study that was performed from 2008 to 2010 in a western part of Japan. Finally, a total of 959 subjects (319 men and 640 women; mean age, 66.4 years) were included. The CSC diameter at C5 level on plain radiographs, cervical cord compression and ISI on sagittal T2 weighted MRI, physical signs related to cervical myelopathy (e.g., the Hoffmann reflex, hyper-reflexia of the patellar tendon, the Babinski reflex, sensory and motor function, and bowel/bladder symptoms) METHODS: This study was funded by Japanese Grant-in-Aid for Scientific Research. There is no conflict of interest. The age-related differences of CSC diameters in men and women were investigated by a descriptive statistics. The prevalence of MRI abnormalities and clinical CM were compared among the groups divided by the CSC diameter (<13 mm, 13-15 mm and ≥15 mm). In addition, a logistic regression analysis was performed to determine the association of the CSC diameter with cervical cord compression/ clinical CM after overall adjustment for age, sex, and BMI. The CSC diameter was narrower with increasing age in both men and women. The prevalence of cervical cord compression, ISI and the clinical CM were significantly higher in narrower CSC group. The prevalence of cervical cord compression, ISI, and CM among subjects with CSC diameter < 13 mm was 38.0%, 5.4%, and 10.1%, respectively. In the logistic model, the CSC diameter was significant predictive factor for the clinical CM (P < .0001). This study firstly confirmed the age-related differences in CSC diameters and the significant association of the narrow CSC diameter with CM in a population-based cohort.
    The spine journal: official journal of the North American Spine Society 04/2014; DOI:10.1016/j.spinee.2014.03.051 · 2.80 Impact Factor
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    ABSTRACT: We aimed to assess the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) and its association with lumbar spondylosis (LS) and knee osteoarthritis (KOA) using a population-based cohort study entitled Research on Osteoarthritis/osteoporosis Against Disability (ROAD). In the baseline ROAD study, which was performed between 2005 and 2007, 1,690 participants in mountainous and coastal areas underwent anthropometric measurements and radiographic examinations of the whole spine (cervical, thoracic, and lumbar) and both knees. They also completed an interviewer-administered questionnaire. Presence of DISH was diagnosed according to Resnick criteria, and LS and KOA were defined as Kellgren-Lawrence (KL) grade ≥3. Among the 1,690 participants, whole-spine radiographs of 1,647 individuals (97.5 %; 573 men, 1,074 women; mean age, 65.3 years) were evaluated. Prevalence of DISH was 10.8 % (men 22.0 %, women 4.8 %), and was significantly higher in older participants (presence of DISH 72.3 years, absence of DISH 64.4 years) and mainly distributed at the thoracic spine (88.7 %). Logistic regression analysis revealed that presence of DISH was significantly associated with older age [+1 year, odds ratio (OR): 1.06, 95 % confidence interval (CI): 1.03-1.14], male sex (OR: 5.55, 95 % CI: 3.57-8.63), higher body mass index (+1 kg/m(2), OR: 1.08, 95 % CI: 1.02-1.14), presence of LS (KL2 vs KL0: 1, OR: 5.50, 95 % CI: 2.81-10.8) (KL ≥3 vs KL0: 1, OR: 4.09, 95 % CI: 2.08-8.03), and presence of KOA (KL ≥3 vs KL0: 1, OR: 1.89, 95 % CI: 1.14-3.10) after adjusting for smoking, alcohol consumption, and residential area (mountainous vs coastal). This cross-sectional population-based study clarified the prevalence of DISH in general inhabitants and its significant association with LS and severe KOA.
    Journal of Bone and Mineral Metabolism 03/2014; 33(2). DOI:10.1007/s00774-014-0583-9 · 2.11 Impact Factor
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    ABSTRACT: Objectives. To examine the onset and resolution of pain and physical functional disability using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and their association with knee osteoarthritis (OA) in the longitudinal large-scale population of the nationwide cohort study, Research on Osteoarthritis/osteoporosis Against Disability (ROAD). Methods. Subjects from the ROAD study who had been recruited during 2005-2007 were followed up 3 years later. A total of 1,578 subjects completed the WOMAC questionnaire at baseline and follow up, and the onset and resolution rate of pain and physical functional disability were examined. We also examined the association of onset of pain and physical functional disability and their resolution with severity of knee OA as well as age, body-mass index and grip strength. Results. After a 3.3-year follow-up, the onset rate of pain was 35.0% and 35.3% in men and women, respectively, and the onset rate of physical functional disability was 38% and 40%, respectively. Resolution rate of pain was 20.3% and 26.2% in men and women, respectively, and resolution rate of physical functional disability was 16% and 14% in men and women, respectively. Knee OA was significantly associated with onset and resolution of pain and physical functional disability in women, but there was no significant association of knee OA with onset of pain and resolution of physical functional disability in men. Conclusions. The present longitudinal study revealed the onset rate of pain and physical functional disability as well as their resolution, and their association with knee OA.
    Modern Rheumatology 03/2014; 24(6). DOI:10.3109/14397595.2014.883055 · 2.21 Impact Factor
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    ABSTRACT: The present study aimed to investigate association of physical activities of daily living with the incidence of certified need of care in the national long-term care insurance (LTCI) system in elderly Japanese population-based cohorts. Of the 3,040 participants in the baseline examination, we enrolled 1,773 (699 men, 1,074 women) aged 65 years or older who were not certified as in need of care-level elderly at baseline. Participants were followed during an average of 4.0 years for incident certification of need of care in the LTCI system. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was used assess function. Associated factors in the baseline examination with the occurrence were determined by multivariate Cox proportional hazards regression analysis. Receiver operating characteristic curve analysis was performed to evaluate cut-off values for discriminating between the occurrence and the non-occurrence group. All 17 items in the WOMAC function domain were significantly associated with the occurrence of certified need of care in the overall population. Cut-off values of the WOMAC function score that maximized the sum of sensitivity and specificity were around 4-6 in the overall population, in men, and in women. Multivariate Cox hazards regression analysis revealed that a WOMAC function score ≥4 was significantly associated with occurrence with the highest hazard ratio (HR) for occurrence after adjusting for confounders in the overall population (HR [95 % confidence interval (CI)] 2.54 [1.76-3.67]) and in women [HR (95 % CI) 3.13 (1.95-5.02)]. A WOMAC function score ≥5 was significantly associated with the highest HR for occurrence in men [HR (95 % CI) 1.88 (1.03-3.43)]. Physical dysfunction in daily living is a predictor of the occurrence of certified need of care. Elderly men with a WOMAC function score ≥5 and women with a score ≥4 should undergo early intervention programs to prevent subsequent deterioration.
    Journal of Orthopaedic Science 02/2014; 19(3). DOI:10.1007/s00776-014-0537-z · 1.01 Impact Factor
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    ABSTRACT: Background Context A narrow cervical spinal canal (CSC) is a well-known risk factor for cervical myelopathy (CM). However, no epidemiologic data of CSC based on a population-based cohort are available. Porpose 1) To investigate the age-related differences in CSC diameters on plain radiographs, 2) To examine the associated MRI abnormalities including cervical cord compression and increased signal intensity (ISI) as well as the clinical CM with the narrow CSC Study Design/Setting: A cross-sectional study Participant Sample Data were obtained from the base-line survey of Wakayama Spine Study that was performed from 2008 to 2010 in a western part of Japan. Finally, a total of 959 subjects (319 men and 640 women; mean age, 66.4 years) were included. Outcome Measures The CSC diameter at C5 level on plain radiographs, cervical cord compression and ISI on sagittal T2 weighted MRI, physical signs related to cervical myelopathy (e.g., the Hoffmann reflex, hyper-reflexia of the patellar tendon, the Babinski reflex, sensory and motor function, and bowel/bladder symptoms) Methods This study was funded by Japanese Grant-in-Aid for Scientific Research. There is no conflict of interest. The age-related differences of CSC diameters in men and women were investigated by a descriptive statistics. The prevalence of MRI abnormalities and clinical CM were compared among the groups divided by the CSC diameter (<13 mm, 13-15 mm and ≥15 mm). In addition, a logistic regression analysis was performed to determine the association of the CSC diameter with cervical cord compression/ clinical CM after overall adjustment for age, sex, and BMI. Results The CSC diameter was narrower with increasing age in both men and women. The prevalence of cervical cord compression, ISI and the clinical CM were significantly higher in narrower CSC group. The prevalence of cervical cord compression, ISI, and CM among subjects with CSC diameter < 13 mm was 38.0%, 5.4%, and 10.1%, respectively. In the logistic model, the CSC diameter was significant predictive factor for the clinical CM (P < .0001). Conclusions This study firstly confirmed the age-related differences in CSC diameters and the significant association of the narrow CSC diameter with CM in a population-based cohort.
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    ABSTRACT: We investigated the midterm results of resection arthroplasty of all 5 metatarsal heads in patients with rheumatoid arthritis and forefoot deformity and analyzed the factors that affect patient satisfaction levels. Of 64 patients (1 male, 63 females), 107 feet were treated with resection arthroplasty for forefoot deformity at our hospital from January 1992 to December 2005. The mean follow-up period was 5.8 ± 3.1 years, with all patients having at least 1 year of follow-up. Of the 64 patients, 75% were satisfied with the surgery. The mean score for the postoperative Japanese Society for Surgery of the Foot lesser metatarsophalangeal-interphalangeal scale was 75.0 ± 15.8 points. Multivariate logistic regression analysis showed that patient-reported dissatisfaction was significantly associated with the recurrence of hammer toe deformity (odds ratio 2.66, 95% confidence interval 1.07 to 6.97), shortening of the resection arthroplasty space (odds ratio 0.85 for a 1-unit increase, 95% confidence interval 0.74 to 0.96), and the recurrence of hallux valgus (odds ratio 1.04 for a 1-unit increase, 95% confidence interval 1.00 to 1.09) during the postoperative period. From our results, interventions to prevent recurrence of hammer toe deformity, especially in toes with preoperative metatarsophalangeal joint dislocations, have been shown to be important in preventing complications and patient dissatisfaction after resection arthroplasty.
    The Journal of foot and ankle surgery: official publication of the American College of Foot and Ankle Surgeons 11/2013; 53(1). DOI:10.1053/j.jfas.2013.09.014 · 0.98 Impact Factor
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    ABSTRACT: The purposes of this study were to investigate the prevalence and distribution of intervertebral disc degeneration (DD) over the entire spine using magnetic resonance imaging (MRI), and to examine the factors and symptoms potentially associated with DD. This study included 975 participants (324 men, mean age of 67.2 years; 651 women, mean age of 66.0 years) with an age range of 21-97 years in the Wakayama Spine Study. DD on MRI was classified into Pfirrmann's system (grades 4 and 5 indicating DD). We assessed the prevalence of DD at each level in the cervical, thoracic, and lumbar regions and the entire spine, and examined DD-associated factors and symptoms. The prevalence of DD over the entire spine was 71% in men and 77% in women aged <50 years, and >90% in both men and women aged >50 years. The prevalence of an intervertebral space with DD was highest at C5/6 (men: 51.5%, women: 46%), T6/7 (men: 32.4%, women: 37.7%), and L4/5 (men: 69.1%, women: 75.8%). Age and obesity were associated with the presence of DD in all regions. Low back pain was associated with the presence of DD in the lumbar region. The current study established the baseline data of DD over the entire spine in a large population of elderly individuals. These data provide the foundation for elucidating the causes and mechanisms of DD.
    Osteoarthritis and Cartilage 11/2013; 22(1). DOI:10.1016/j.joca.2013.10.019 · 4.66 Impact Factor
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    ABSTRACT: The Longitudinal Cohorts of Motor System Organ (LOCOMO) study was initiated in 2008 through a grant from the Ministry of Health, Labour, and Welfare of Japan to integrate information from several cohorts established for the prevention of musculoskeletal diseases. We integrated the information of 12,019 participants (3,959 men and 8,060 women) in the cohorts comprising nine communities located in Tokyo (two regions: Tokyo-1 and Tokyo-2), Wakayama [two regions: Wakayama-1 (mountainous region) and Wakayama-2 (seaside region)], Hiroshima, Niigata, Mie, Akita, and Gunma prefectures. The baseline examination of the LOCOMO study consisted of an interviewer-administered questionnaire, anthropometric measurements, medical information recording, X-ray radiography, and bone mineral density measurement. The prevalence of knee pain was 32.7 % (men 27.9 %; women 35.1 %) and that of lumbar pain was 37.7 % (men 34.2 %; women 39.4 %). Among the 9,046 individuals who were surveyed on both knee pain and lumbar pain at the baseline examination in each cohort, we noted that the prevalence of both knee pain and lumbar pain was 12.2 % (men 10.9 %; women 12.8 %). Logistic regression analysis showed that higher age, female sex, higher body mass index (BMI), living in a rural area, and the presence of lumbar pain significantly influenced the presence of knee pain. Similarly, higher age, female sex, higher BMI, living in a rural area, and the presence of knee pain significantly influenced the presence of lumbar pain. Thus, by using the data of the LOCOMO study, we clarified the prevalence of knee pain and lumbar pain, their coexistence, and their associated factors.
    Journal of Bone and Mineral Metabolism 11/2013; 32(5). DOI:10.1007/s00774-013-0522-1 · 2.11 Impact Factor
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    ABSTRACT: To examine the incidence of certified need of care in the national long-term care insurance (LTCI) system, and to determine its risk factors in the elderly of Japanese population-based cohorts of the Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) study. Of the 3040 participants in the baseline examination of the ROAD study, we enrolled 1773 (699 men, 1074 women) aged 65 years or older who were not certified as in need of care level elderly at baseline. Participants were followed for incident certification of need of care in the LTCI system. Associated factors in the baseline examination with occurrence were determined by multivariate Cox proportional hazards regression analysis. Muscle dysfunction was defined in accordance with the European Working Group on Sarcopenia in Older People algorithm for screening sarcopenia. A total of 54 men and 115 women were certified as in need of care level elderly during the average 4.0-year follow up. The incidence was 2.0 and 2.5 per 100 person-years in men and women, respectively. Identified risk factors were region, age, body mass index <18.5 or ≥27.5 kg/m(2) , grip strength, knee extension torque, usual gait speed, chair stand time and muscle dysfunction. Both underweight and obesity, as well as low muscle strength and physical ability, are risk factors for certification of need of care. Considering muscle dysfunction is a risk factor for occurrence, screened individuals are recommended to receive early intervention programs regardless of muscle volume. Geriatr Gerontol Int 2013; ●●: ●●-●●.
    Geriatrics & Gerontology International 09/2013; 14(3). DOI:10.1111/ggi.12155 · 1.58 Impact Factor

Publication Stats

11k Citations
1,471.13 Total Impact Points

Institutions

  • 2011–2015
    • National Rehabilitation Center for Persons with Disabilities
      Tokorozawa, Saitama, Japan
    • KAKEN HOSPITAL
      Ichikawa, Chiba, Japan
  • 2012–2014
    • Wakayama Medical University
      • Department of Orthopedic Surgery
      Wakayama, Wakayama, Japan
    • Saitama University
      Saitama, Saitama, Japan
  • 1991–2014
    • The University of Tokyo
      • • Department of Orthopaedic Surgery and Spinal Surgery
      • • Division of Sensory and Motor System Medicine
      Tōkyō, Japan
  • 2004–2011
    • Tokyo Medical University
      • Department of Orthopedic Surgery
      Edo, Tōkyō, Japan
    • Kobe University
      Kōbe, Hyōgo, Japan
  • 2008
    • Tokyo Metropolitan Komagome Hospital
      Edo, Tōkyō, Japan
  • 2007
    • Japan Society for the Promotion of Science
      Edo, Tōkyō, Japan
    • Hiroshima University
      • Department of Dental and Medical Biochemistry
      Hiroshima-shi, Hiroshima-ken, Japan
  • 2006
    • Teikyo University
      Edo, Tōkyō, Japan
    • Osaka City University
      • Graduate School of Medicine
      Ōsaka, Ōsaka, Japan
  • 2005
    • Kyorin University
      Edo, Tōkyō, Japan
    • Osaka Kosei Nenkin Hospital
      Ōsaka, Ōsaka, Japan
    • Chiba Children's Hospital
      Tiba, Chiba, Japan
  • 1998–2005
    • Saitama Medical University
      Saitama, Saitama, Japan
  • 2002
    • Teikyo University Hospital
      Edo, Tōkyō, Japan