The cumulative incidence of and risk factors for morphometric severe vertebral fractures in Japanese men and women: the ROAD study third and fourth surveys.

This population-based cohort study with a 3-year follow-up revealed that the annual incidence rates of vertebral fracture (VF) and severe VF (sVF) were 5.9%/year and 1.7%/year, respectively. The presence of mild VF at the baseline was a significant risk factor for incident sVF in participants without prevalent sVF. INTRODUCTION: This study aimed to estimate the incidence of morphometric vertebral fracture (VF) and severe VF (sVF) in men and women and clarify whether the presence of a mild VF (mVF) increases the risk of incident sVF. METHODS: Data from the population-based cohort study, entitled the Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) study, were analyzed. In total, 1190 participants aged ≥ 40 years (mean age, 65.0 ± 11.2) years completed whole-spine lateral radiography both at the third (2012-2013, baseline) and fourth surveys performed 3 years later (2015-2016, follow-up). VF was defined using Genant's semi-quantitative (SQ) method: VF as SQ ≥ 1, mVF as SQ = 1, and sVF as SQ ≥ 2. Cumulative incidence of VF and sVF was estimated. Multivariate logistic regression analyses were performed to evaluate risk factors for incident sVF. RESULTS: The baseline prevalence of mVF and sVF were 16.8% and 6.0%, respectively. The annual incidence rates of VF and sVF were 5.9%/year and 1.7%/year, respectively. The annual incidence rates of sVF in participants without prevalent VF, with prevalent mVF, and with prevalent sVF were 0.6%/year, 3.8%/year, and 11.7%/year (p < 0.001), respectively. Multivariate logistic regression analyses in participants without prevalent sVF showed that the adjusted odds ratios for incident sVF were 4.12 [95% confident interval 1.85-9.16] and 4.53 [1.49-13.77] if the number of prevalent mVF at the baseline was 1 and ≥ 2, respectively. CONCLUSIONS: The annual incidence rates of VF and sVF were 5.9%/year and 1.7%/year, respectively. The presence of prevalent mVF was an independent risk factor for incident sVF.

Incidence rate and risk factors for radiographic hip osteoarthritis in Japanese men and women: a 10-year follow-up of the ROAD study.

OBJECTIVE: To investigate the incidence and progression rate of radiographic hip osteoarthritis (OA) and its risk factors in Japanese men and women using a large-scale population of a nationwide cohort study, Research on Osteoarthritis/osteoporosis Against Disability (ROAD). METHODS: From the baseline survey of the ROAD study, 2,975 participants (1,043 men and 1,932 women) aged 23-94 years (mean, 70.2 years) living in urban, mountainous, and coastal communities were followed up with hip radiography at 3, 7, and 10 years (mean follow-up, 7.1 years). Radiographs were scored using the Kellgren/Lawrence (K/L) grading system, and radiographic hip OA was defined as K/L ≥ 2. The incidence and progression rate of hip OA were examined. Acetabular dysplasia was defined as a central-edge angle <20°. Cox's proportional hazard model was used to assess risk factors for incident and progressive radiographic hip OA. RESULTS: The incidence rate of radiographic hip OA was 5.6/1,000 person-years and 8.4/1,000 person-years in men and women, respectively. The progression rate of hip OA was 2.2/1,000 person-years and 6.0/1,000 person-years in men and women, respectively. The significant risk factors for incident hip OA were age, obesity, and acetabular dysplasia at baseline (hazard risk [HR] 1.05, 95% confidence interval [CI] 1.03-1.08; 1.78, 1.10-2.75; 2.06, 1.30-3.17, respectively). The significant risk factors for progressive hip OA were baseline hip pain and acetabular dysplasia (HR 5.68, 95%CI 1.07-22.61; 14.78, 3.66-56.06, respectively). CONCLUSION: Continued longitudinal surveys of the ROAD study will contribute to knowledge about and potential prevention of incident and progressive hip OA.

A population-based study identifies an association of THBS2 with intervertebral disc degeneration.

OBJECTIVE: To clarify the genetic mechanisms underlying intervertebral disc degeneration (IDD), we examined the associations between single-nucleotide polymorphisms (SNPs) and indicated as coefficient of interaction term (IDD) in a general population in Japan. METHODS: This was a cross-sectional study. In 1,605 participants, C2-3 to L5/S1 in the total spine magnetic resonance imaging (MRI) were evaluated using the Pfirrmann's scoring system. Disc scores of 4 and 5 were defined as IDD. Eight SNPs in eight genes associated with IDD were examined at each disc level, considering the non-genetic risk factors of age, sex, and body mass index (BMI). RESULTS: The highest odds ratio was found for rs9406328 in the THBS2 gene at disc level T12-L1 (OR 1.27, 95%CI 1.05 to 1.53), and this association was strengthened after adjustment for age using logistic regression (OR 1.37, 95%CI 1.12 to 1.67). Among participants aged <50 years and 50-59, the average IDD score in those with 2 risk alleles of rs9406328 was markedly higher than in those with 0 or 1 risk allele, and the difference is much wider than the elderly participants. It indicates the genetic effect of rs9406328 is stronger in the younger age groups. Finally, multiple linear regression analyses of the association between rs9406328 and IDD, adjusted for age, sex, and BMI at each disc level, showed a statistical interaction between age and the number of risk alleles at C7-T1, T3-4 and T4-T5 as well as T12-L1. CONCLUSION: CONCLUSION: The association between rs9406328 in THBS2 and IDD was replicated. The contributions of genetic and environmental factors to IDD differed by disc level.

Do sarcopenia and/or osteoporosis increase the risk of frailty? A 4-year observation of the second and third ROAD study surveys.

In this 4-year follow-up study including 1083 subjects (≥ 60 years), the prevalence of frailty was estimated to be 5.6%; osteoporosis was found to be significantly associated with frailty. Moreover, the presence of both osteoporosis and sarcopenia increased the risk of frailty compared to the presence of osteoporosis or sarcopenia alone. INTRODUCTION: This study aims to examine the contribution of sarcopenia and osteoporosis to the occurrence of frailty using 4-year follow-up information of a population-based cohort study. METHODS: The second survey of the Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) study was conducted between 2008 and 2010; 1083 subjects (aged ≥ 60 years, 372 men, 711 women) completed all examinations on frailty, sarcopenia, and osteoporosis, which were defined using Fried's definition, Asian Working Group for Sarcopenia criteria, and WHO criteria, respectively. The third survey was conducted between 2012 and 2013; 749 of 1083 individuals enrolled from the second survey (69.2%, 248 men, 501 women) completed assessments identical to those in the second survey. RESULTS: The prevalence of frailty in the second survey was 5.6% (men, 3.8%; women, 6.6%). The cumulative incidence of frailty was 1.2%/year (men, 0.8%/year; women, 1.3%/year). After adjustment for confounding factors, logistic regression analysis indicated that osteoporosis was significantly associated with the occurrence of frailty (odds ratio, 3.07; 95% confidence interval, 1.26-7.36; p = 0.012). Moreover, the occurrence of frailty significantly increased according to the presence of osteoporosis and sarcopenia (odds ratio vs. neither osteoporosis nor sarcopenia: osteoporosis alone, 2.50; osteoporosis and sarcopenia, 5.80). CONCLUSIONS: Preventing osteoporosis and coexistence of osteoporosis and sarcopenia may help reduce the risk of frailty.

Radiographic measurements of the hip joint and their associations with hip pain in Japanese men and women: the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study.

OBJECTIVE: To investigate radiographic measurements of the hip joint and their associations with hip pain, and the prevalence of acetabular dysplasia defined by radiographic measurements of the hip joint in Japanese men and women using the large-scale population-based cohort of the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study. METHODS: From the baseline survey of the ROAD study (cross-sectional study), 2963 participants (1040 men, 1923 women; mean age, 70.2 years) were analyzed. All participants underwent radiographic examinations of both hips using an anteroposterior view under weight-bearing. Minimum joint space width (mJSW), central-edge (CE) angle, acetabular depth-to-width ratio (ADR), and acetabular head index (AHI) were measured. Associations between these radiographic measurements and hip pain were assessed by calculating odds ratios (ORs) using multivariable logistic-regression analysis. Acetabular dysplasia was defined as a CE angle <20°. RESULTS: Mean radiographic measurements of the hip joint for men were: mJSW, 3.8 mm; CE angle, 30.6°; ADR, 262.1 per 1000; and AHI, 81.4%. For women, these values were: mJSW, 3.4 mm; CE angle, 29.9°; ADR, 262.7 per 1000; and AHI, 81.2%. Associations were seen between hip pain and each of mJSW, CE angle, ADR, and AHI (OR 4.52, 95% confidence interval 3.45-5.97; 1.14, 1.11-1.18; 1.31, 1.24-1.40; and 1.15, 1.12-1.18, respectively). Acetabular dysplasia showed an overall prevalence of 13.9%, and was significantly more prevalent in women than in men (P = 0.012). CONCLUSION: The present study of radiographic measurements of the hip joint showed that mJSW, CE angle, ADR, and AHI were associated with hip pain.

Progression, incidence, and risk factors for intervertebral disc degeneration in a longitudinal population-based cohort: the Wakayama Spine Study.

OBJECTIVE: The present study examined the progression, incidence, and risk factors for intervertebral disc degeneration (DD) throughout the lumbar spine using magnetic resonance imaging (MRI) in a large population-based cohort. METHODS: We followed up 617 subjects for more than 4 years as part of the Wakayama Spine Study. 1) "Progression of DD" in each of the entire, upper (L1/2 to L3/4) and lower (L4/5 and L5/S1) lumbar spine was defined as Pfirrmann grade progression at follow-up in at least one disc in the affected region. 2) "Incidence of DD" in each of these regions was defined if all discs were grade 3 or lower (white disc) at baseline, and at least one disc had progressed to grade 4 or higher (black disc) at follow-up. Logistic regression analyses were used to determine the risk factors for progression and incidence of DD. RESULTS: DD progression and incidence in the entire lumbar spine were 52.0% and 31.6% in men, and 60.4% and 44.7% in women, respectively. Women was associated with DD progression in the upper lumbar spine (odds ratio [OR] = 1.68, 95% confidence interval [CI] = 1.18-2.42). Aging was associated with the incidence of DD in each region (entire: OR = 1.14, CI = 1.06-1.14; upper: OR = 1.10, CI = 1.05-1.15; lower: OR = 1.11, CI = 1.05-1.19). Diabetes mellitus (DM) was associated with the incidence of DD in the upper lumbar spine (OR = 6.83, CI = 1.07-133.7). CONCLUSION: This 4-year longitudinal study is the first to demonstrate DD progression and incidence in the lumbar spine and their risk factors in a large population-based cohort.

Is osteoporosis a predictor for future sarcopenia or vice versa? Four-year observations between the second and third ROAD study surveys.

In a 4-year follow-up study that enrolled 1099 subjects aged ≥60 years, sarcopenia prevalence was estimated at 8.2%. Moreover, the presence of osteoporosis was significantly associated with short-term sarcopenia occurrence, but the reciprocal relationship was not observed, suggesting that osteoporosis would increase the risk of osteoporotic fracture and sarcopenia occurrence. INTRODUCTION: The present 4-year follow-up study was performed to clarify the prevalence, incidence, and relationships between sarcopenia (SP) and osteoporosis (OP) in older Japanese men and women. METHODS: We enrolled 1099 participants (aged, ≥60 years; 377 men) from the second survey of the Research on Osteoarthritis/Osteoporosis against Disability (ROAD) study (2008-2010) and followed them up for 4 years. Handgrip strength, gait speed, skeletal muscle mass, and bone mineral density were assessed. SP was defined according to the Asian Working Group for Sarcopenia. OP was defined based on the World Health Organization criteria. RESULTS: SP prevalence was 8.2% (men, 8.5%; women, 8.0%) in the second survey. In those with SP, 57.8% (21.9%; 77.6%) had OP at the lumbar spine L2-4 and/or femoral neck. SP cumulative incidence was 2.0%/year (2.2%/year; 1.9%/year). Multivariate regression analysis revealed that OP was significantly associated with SP occurrence within 4 years (odds ratio, 2.99; 95% confidence interval, 1.46-6.12; p < 0.01), but the reciprocal relationship was not significantly observed (2.11; 0.59-7.59; p = 0.25). CONCLUSIONS: OP might raise the short-term risk of SP incidence. Therefore, OP would not only increase the risk for osteoporotic fracture but may also increase the risk for SP occurrence.

Prevalence of radiographic hip osteoarthritis and its association with hip pain in Japanese men and women: the ROAD study.

OBJECTIVE: Although hip osteoarthritis (OA) is a major cause of hip pain and disability in elderly people, few epidemiologic studies have been performed. We investigated the prevalence of radiographic hip OA and its association with hip pain in Japanese men and women using a large-scale population of a nationwide cohort study, Research on Osteoarthritis/osteoporosis Against Disability (ROAD). METHODS: From the baseline survey of the ROAD study, 2975 participants (1043 men and 1932 women), aged 23-94 years (mean 70.2 years), living in urban, mountainous, and coastal communities were analyzed. The radiographic severity at both hips was determined by the Kellgren/Lawrence (K/L) grading system. Radiographic hip OA was defined as K/L ≥ 2, and severe radiographic hip OA as K/L ≥ 3. RESULTS: The crude prevalence of radiographic hip OA was 18.2% and 14.3% in men and women, respectively, that of severe radiographic hip OA was 1.34% and 2.54%, and that of symptomatic K/L ≥ 2 OA was 0.29% and 0.99%, respectively. The crude prevalence of hip OA, including severe OA, was not age-dependent in men or women. Male sex was a risk factor for radiographic hip OA, whereas female sex was a risk factor for severe radiographic hip OA and hip pain. Compared with K/L = 0/1, hip pain was significantly associated with K/L ≥ 3, but not with K/L = 2. CONCLUSION: The present cross-sectional study revealed the prevalence of radiographic hip OA and severe hip OA in Japanese men and women. Hip pain was strongly associated with K/L ≥ 3.

Factors affecting changes in the serum levels of 25-hydroxyvitamin D: a 3-year follow-up of the ROAD study.

UNLABELLED: In this 3-year population-based cohort study, among 1346 subjects, the mean annual change in the serum 25-hydroxyvitamin D levels was 7.6 %/year, which tended to increase during the 3-year period. Multivariate regression analysis indicated that the L2-4 bone mineral density and total daily energy intake were significant independent associated factors. INTRODUCTION: The aim of this study was to clarify the change rate of the serum levels of 25-hydroxyvitamin D (25D) and the associated factors in a general Japanese population during a 3-year period. METHODS: The baseline survey of Research on Osteoarthritis/osteoporosis Against Disability study (ROAD), a large-scale population-based cohort study, was performed between 2005 and 2007, and a follow-up survey was repeated 3 years later. Among 1690 participants at baseline, the change rate of the serum 25D levels were assessed in 1346 individuals (79.6 %; 458 men and 888 women) who completed measurements of 25D at both the baseline and follow-up examinations. The change rate was calculated, and the factors associated with the changes in the 25D levels were determined using multivariate regression analysis after adjustment for age, gender, body mass index, participated month, and regional differences at baseline. RESULTS: The mean (standard deviation) change rate of the 25D levels in all subjects was 7.6 (13.3) %/year (men, 8.2 [12.4] %/year; women, 7.3 [13.7] %/year). Multivariate regression analysis indicated that higher bone mineral density at lumbar spine L2-4 (p = 0.05) and total daily energy intake (p = 0.04) were significantly associated with the change rate of the 25D levels. CONCLUSIONS: The serum levels of 25D tended to increase over the 3-year period, and higher lumbar bone mineral density and daily energy intake were found to be associated with increases in the 25D levels over time.

Joint space narrowing, body mass index, and knee pain: the ROAD study (OAC1839R1).

OBJECTIVE: 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. METHODS: 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 osteoarthritis (OA) computer-aided diagnosis system. RESULTS: From the 3040 participants in the ROAD study, the present study analyzed 2733 participants who completed the radiographic examinations and questionnaires regarding knee pain (975 men and 1758 women; mean age, 69.9 ± 11.2 years). Subjects with lateral knee OA were excluded. After adjustment for age and Body mass index (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. BMI was found to have a distinct effect on the association of mJSW with pain. CONCLUSION: 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.

Serum levels of 25-hydroxyvitamin D and the occurrence of musculoskeletal diseases: a 3-year follow-up to the road study.

UNLABELLED: Assessment of serum 25-hydroxyvitamin D levels in association with the occurrence of musculoskeletal diseases using a population-based cohort study design revealed that serum 25-hydroxyvitamin D levels could predict the occurrence of osteoporosis at the femoral neck within 3 years, but not the occurrence of knee osteoarthritis or lumbar spondylosis. INTRODUCTION: The aim of this study is to clarify the association between serum 25-hydroxyvitamin D (25D) levels and occurrence of osteoporosis and osteoarthritis in the general population. METHODS: The Research on Osteoarthritis/Osteoporosis Against Disability study, a large-scale population-based cohort study, was performed during 2005-2007. Serum 25D levels were measured in 1,683 participants. Of these, 1,384 individuals (81.9%) completed a second follow-up survey 3 years later. Osteoporosis was defined according to World Health Organization criteria, in which osteoporosis is diagnosed by T-scores of bone mineral density (BMD) that are 2.5 standard deviations (SD) less than normal BMD. Knee osteoarthritis and lumbar spondylosis were defined as Kellgren-Lawrence grade ≥2, using paired X-ray films. Cumulative incidences were determined according to changes in measurements using World Health Organization criteria for osteoporosis or Kellgren-Lawrence grades for osteoarthritis between the baseline and second survey. RESULTS: The mean (SD) serum 25D level of the 1,384 participants in both surveys was 23.4 ng/mL (6.5). The annual cumulative incidences of osteoporosis at L2-4 and the femoral neck were 0.76 and 1.83%/year, respectively. The incidences of knee osteoarthritis and lumbar spondylosis were 3.3 and 11.4%/year, respectively. After adjusting for potential associated factors, logistic regression analyses revealed that the odds ratio for the occurrence of femoral neck osteoporosis significantly decreased as serum 25D levels increased (+1 SD; odds ratio 0.67; 95% confidence interval 0.49-0.92; p = 0.014). CONCLUSIONS: Higher serum 25D levels may prevent the occurrence of osteoporosis at the femoral neck, but not knee osteoarthritis, lumbar spondylosis, or osteoporosis at L2-4.

Prevalence and progression of radiographic ossification of the posterior longitudinal ligament and associated factors in the Japanese population: a 3-year follow-up of the ROAD study.

SUMMARY: The prevalence of radiographic cervical ossification of the posterior longitudinal ligament (OPLL) in 1,562 Japanese from a population-based cohort was 1.9 %. The presence of OPLL showed a significant association with the femoral neck bone mineral density (BMD), presence of diffuse idiopathic skeletal hyperostosis (DISH) and plasma pentosidine levels. Only one new case of radiographic OPLL was detected, but OPLL progressed in all affected subjects. INTRODUCTION: The purpose of this study was to clarify the prevalence and progression of radiographic OPLL and the associated factors, using the population-based cohort Research on Osteoarthritis/osteoporosis Against Disability (ROAD). METHODS: In the ROAD study, 1,690 participants underwent X-ray examination of the entire spine and both knees. Radiographic OPLL, lumbar spondylosis, knee osteoarthritis and DISH were diagnosed by a single, well-experienced orthopaedic surgeon. An interviewer-administered questionnaire and tests for anthropometric measurements were administered, and the BMDs of the lumbar spine and proximal femur were determined. A new OPLL case was considered if heterotopic ossification in the posterior longitudinal ligament was absent at baseline but present during follow-up. Progression was defined as an increase in the maximum length or width of the ossification at follow-up over that at baseline. RESULTS: Radiographic OPLL was detected in 30 (17 men, 13 women) of 1,562 individuals who underwent X-ray examination of the cervical spine (prevalence = 1.9 %). Its prevalence was significantly higher in men than in women (p = 0.007), but no association with age was observed. In a logistic regression analysis, OPLL showed a significant association with the femoral neck BMD, presence of DISH and plasma pentosidine levels. Only one new case of radiographic OPLL was detected, but OPLL progressed in all affected subjects. CONCLUSION: This population-based study clarified the prevalence of radiographic OPLL in the Japanese population as well as its progression. OPLL showed significant association with plasma pentosidine levels, BMD and DISH.

Exercise habits during middle age are associated with lower prevalence of sarcopenia: the ROAD study.

SUMMARY: The present cross-sectional study investigated the prevalence of sarcopenia and clarified its associated factors in 1,000 elderly participants of Japanese population-based cohorts. Exercise habit in middle age was associated with low prevalence of sarcopenia in older age, suggesting that it is a protective factor against sarcopenia in older age. INTRODUCTION: The present study investigated the prevalence of sarcopenia using the European Working Group on Sarcopenia in Older People (EWGSOP) definition, and clarified the association of sarcopenia with physical performance in the elderly participants of Japanese population-based cohorts of the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study. METHODS: We enrolled 1,000 participants (aged ≥65 years) from the second visit of the ROAD study who had completed assessment of handgrip strength, gait speed, and skeletal muscle mass measured by bioimpedance analysis. Presence of sarcopenia was determined according to the EWGSOP algorithm. Information collected included exercise habits in middle age. RESULTS: Prevalence of sarcopenia was 13.8 % in men and 12.4 % in women, and tended to be significantly higher according to increasing age in both sexes. Factors associated with sarcopenia, as determined by logistic regression analysis, were chair stand time (odds ratio [OR], 1.09; 95 % confidence interval [CI], 1.04-1.14), one-leg standing time (OR, 0.97; 95 % CI, 0.96-0.99), and exercise habit in middle age (OR, 0.53; 95 % CI, 0.31-0.90). Exercise habit in middle age was associated with low prevalence of sarcopenia in older age. Furthermore, linear regression analysis revealed that exercise habits in middle age were significantly associated with grip strength (P < .001), gait speed (P < .001), and one-leg standing time (P = .005) in older age. CONCLUSIONS: This cross-sectional study suggests that exercise habit in middle age is a protective factor against sarcopenia in older age and effective in maintaining muscle strength and physical performance in older age.

Prevalence and distribution of intervertebral disc degeneration over the entire spine in a population-based cohort: the Wakayama Spine Study.

OBJECTIVES: 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. DESIGN: 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. RESULTS: 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. CONCLUSION: 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.

Profiles of vitamin D insufficiency and deficiency in Japanese men and women: association with biological, environmental, and nutritional factors and coexisting disorders: the ROAD study.

UNLABELLED: Assessments of serum 25-hydroxyvitamin D levels in 1,683 Japanese from a population-based cohort revealed prevalences of vitamin D insufficiency and deficiency were 81.3 and 1.2%, respectively. Vitamin D deficiency was significantly associated with female sex, examined month, current smoking, lack of regular walking, higher intact parathyroid hormone (iPTH), and poor daily vitamin D intake. INTRODUCTION: To clarify the characteristics of subjects with vitamin D insufficiency and deficiency among men and women in the general Japanese population. METHODS: We initiated research on osteoarthritis/osteoporosis against disability (ROAD), a large-scale population-based cohort study, in 2005-2007. Blood examination was performed to measure serum 25-hydroxyvitamin D (25D) and iPTH levels and biochemical markers of bone turnover in 1,683 participants (595 men, 1,088 women). Participants completed an interviewer-administered questionnaire, measurements of bone mineral density, and x-ray examination. Vitamin D deficiency and insufficiency were defined by serum 25D levels <10 and ≥10 but <30 ng/mL, respectively. RESULTS: The prevalence of vitamin D insufficiency and deficiency was 81.3 and 1.2%, respectively. Multinominal logistic regression analyses using potentially confounding variables revealed vitamin D insufficiency was significantly associated with age (+1 year, relative risk ratio, 0.98; 95% confidence interval, 0.96-0.99), gender (women vs. men, 2.28; 1.59-3.30), residing areas (coastal area vs. mountainous area, 0.58; 0.41-0.81), examined month (October, November, December vs. January, 0.51; 0.34-0.76), and serum levels of iPTH (+1 pg/mL, 1.02; 1.01-1.03). Vitamin D deficiency was significantly characterised by female sex (20.5; 3.1-136.7), examined month (0.28; 0.09-0.95), current smoking habit (6.39; 1.78-23.0), lack of regular outside walking (3.96; 1.34-11.7), higher iPTH (1.02; 1.01-1.03) and poor daily vitamin D intake (+10 µg/day, 0.48; 0.24-0.93). CONCLUSIONS: A high prevalence of vitamin D insufficiency and a low prevalence of vitamin D deficiency were found in Japanese men and women, and the characteristics of vitamin D status were clarified.

Associations between radiographic lumbar spinal stenosis and clinical symptoms in the general population: the Wakayama Spine Study.

OBJECTIVE: Many asymptomatic individuals have radiographic lumbar spinal stenosis (LSS), but the prevalence of symptoms among individuals with radiographic LSS has not yet been established. The purpose of this study was to clarify the association between radiographic LSS and clinical symptoms in the general population. METHODS: In this cross-sectional study, data from 938 participants (308 men, 630 women; mean age, 66.3 years; range, 40-93 years) were analyzed. The severity of radiographic LSS, including central stenosis, lateral stenosis, and foraminal stenosis, was assessed by mobile magnetic resonance imaging and rated qualitatively. Assessment of clinical symptoms was based on the definition of symptomatic LSS in the North American Spine Society guideline. RESULTS: We found that 77.9% of participants had more than moderate central stenosis and 30.4% had severe central stenosis. Logistic regression analysis after adjustment for age, sex, body mass index, and severity of radiographic LSS showed that severe central stenosis was related to clinical symptoms. However, only 17.5% of the participants with severe central stenosis were symptomatic. CONCLUSION: Although radiographic LSS was common in our cohort, which resembled the general Japanese population, symptomatic persons were relatively uncommon.

Physical performance, bone and joint diseases, and incidence of falls in Japanese men and women: a longitudinal cohort study.

SUMMARY: This study examined whether physical performance and bone and joint diseases were risk factors for falls in 745 men and 1,470 women from the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study (mean, 69.7 years). Slower walking speed was a risk factor for falls in men and women. Knee pain was a risk factor for falls in women. INTRODUCTION: The objective of the present study was to clarify the incidence of falls by sex and age and to determine whether physical performance and bone and joint diseases are risk factors for falls in men and women using a large-scale population-based cohort of the ROAD. METHODS: A total of 745 men and 1,470 women were analyzed in the present study (mean age, 68.5 years). A questionnaire assessed the number of falls during 3 years of follow-up. Grip strength and walking speed were measured at baseline. Knee and lumbar spine radiographs were read by Kellgren-Lawrence (KL) grade; radiographic knee osteoarthritis and lumbar spondylosis were defined as KL = 3 or 4. Knee and lower back pain were estimated by an interview. RESULTS: During a mean follow-up of 3 years, 141 (18.9 %) men and 362 (24.6 %) women reported at least one fall. Slower walking speed was a risk factor for falls in men (0.1 m/s decrease; odds ratio [OR], 1.15; 95 % confidence interval [CI], 1.09-1.23) and women (0.1 m/s decrease; OR, 1.05; 95 % CI, 1.01-1.10). Knee pain was also a risk factor for falls (OR, 1.38; 95 % CI, 1.03-1.84) in women, but lower back pain was not. CONCLUSION: We examined the incidence and risk factors for falls in men and women. Slower walking speed was a risk factor for falls in men and women. Knee pain was a risk factor for falls in women.

Accumulation of metabolic risk factors such as overweight, hypertension, dyslipidaemia, and impaired glucose tolerance raises the risk of occurrence and progression of knee osteoarthritis: a 3-year follow-up of the ROAD study.

OBJECTIVE: To clarify the association between the occurrence and progression of knee osteoarthritis (KOA) with components of metabolic syndrome (MS), including overweight (OW), hypertension (HT), dyslipidaemia (DL), and impaired glucose tolerance (IGT), in a general population. DESIGN: From the large-scale population-based cohort study entitled Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) initiated in 2005, 1,690 participants (596 men, 1,094 women) residing in mountainous and coastal areas were enrolled. Of these, 1,384 individuals (81.9%; 466 men, 918 women) completed the second survey, including knee radiography, 3 years later. KOA was defined as Kellgren-Lawrence (KL) grade ≥ 2 using paired X-ray films. Based on changes in KL grades between the baseline and second surveys, cumulative incidence and progression of KOA were determined. OW, HT, DL, and IGT at baseline were assessed using standard criteria. RESULTS: The cumulative incidence of KOA among 1,384 completers over 3 years was 3.3%/year, and progression in KL grades for either knee, 8.0%/year. Logistic regression analyses after adjusting for potential risk factors revealed that the odds ratio (OR) for the occurrence of KOA significantly increased according to the number of MS components present (OR vs no component: one component, 2.33; two components, 2.82; ≥three components, 9.83). Similarly, progression of KOA significantly increased according to the number of MS components present (OR vs no component: one component, 1.38; two components, 2.29; ≥three components: 2.80). CONCLUSION: Accumulation of MS components is significantly related to both occurrence and progression of KOA. MS prevention may be useful in reducing future KOA risk.

Prevalence of symptomatic lumbar spinal stenosis and its association with physical performance in a population-based cohort in Japan: the Wakayama Spine Study.

OBJECTIVE: The purpose of this study was to investigate the prevalence of symptomatic lumbar spinal stenosis (LSS) and to clarify the association between symptomatic LSS and physical performance using magnetic resonance imaging (MRI) in a population-based cohort. DESIGN: This cross-sectional study was performed as a part of the research on osteoarthritis/osteoporosis against disability (ROAD) in Japan and 1,009 subjects (335 men, 674 women, mean age 66.3 years, age range 21-97 years) were analyzed. An experienced orthopedic surgeon obtained the medical history and performed the physical testing for all participants. Symptomatic LSS diagnostic criteria required the presence of both symptoms and radiographic LSS findings. A 6-m walking time, chair standing time, and one-leg standing time were obtained from all participants. RESULTS: The prevalence of symptomatic LSS was 9.3% (95% confidence interval [CI]: 7.7-11.3) overall, 10.1% (CI: 7.4-13.8) in men and 8.9% (CI: 7.0-11.3) in women. There was a difference in the prevalence with increasing age by gender. The LSS prevalence showed little difference with age greater than 70 years for men, but the LSS prevalence for women was higher with increasing age. Among physical performance measures, 6-m walking time at a maximal pace was significantly associated with symptomatic LSS (P = 0.03). CONCLUSION: The prevalence of symptomatic LSS was approximately 10% in a cohort resembling the general Japanese population. A 6-m walking time at a maximal pace was a more sensitive index than walking at a usual pace in assessing decreased physical performance associated with symptomatic LSS.

Prevalence of vertebral fracture in Asian men and women: comparison between Hong Kong, Thailand, Indonesia and Japan.

OBJECTIVES: Little is known about the prevalence of vertebral fracture among Asians. This study investigated the prevalence of radiographically defined vertebral fracture, and identified associated risk factors in the aged population of four Asian countries. STUDY DESIGN: In total, 1588 males and females aged ≥ 65 years were recruited from Hong Kong, Thailand, Indonesia and Japan. METHODS: Standard X-rays for the spine were taken and vertebral heights were measured. Vertebral fracture was defined as a reduction of >3 standard deviations in vertebral height ratio. Bone mineral density (BMD) of the hip was measured by dual energy X-ray absorptiometry, and anthropometric measurements were taken in Hong Kong and Japan. Other relevant data were entered in a standard questionnaire. RESULTS: The prevalence of vertebral fracture for both males and females was highest in Japan for younger (65-74 years) and older (≥ 75 years) age groups (36.6% and 37.6% for males; 18.8% and 28.7% for females). Lower hip BMD was associated with vertebral fracture in both sexes. Older age, lower quality of life score on Short Form-12 (physical), past longest occupation as a farmer, and history of cataract were significantly associated with vertebral fracture in females. However, smoking did not appear to be an important risk factor for vertebral fracture. CONCLUSIONS: Radiographic assessments for vertebral fracture were performed in all four Asian countries. The prevalence of vertebral fracture was highest in Japan. Lower hip BMD, poorer physical condition and past longest occupation as a farmer were associated with vertebral fracture.