Serum cystatin C level is associated with locomotive syndrome risk and can be an early predictor in community-living people: The Yakumo study

How global spine sagittal alignment and spinal degeneration affect locomotive syndrome risk in the elderly

BACKGROUND

The aim of this study was to delineate the features of the locomotive syndrome (LS) risk stage in the elderly population, encompassing global spine sagittal alignment, visible spinal degenerative changes on plain radiographs, muscle strength, physical capabilities, and low back pain (LBP).

METHODS

The study enrolled 232 subjects, evaluated using plain radiographs. The evaluation included measurements of lumbar lordosis (LLA), thoracic kyphosis (TKA), spinal inclination (SIA) angles, and sagittal vertical axis. Assessments included lumbar osteophyte formation (LOF) and lumbar disc height (LDH) to examine spinal degenerative changes. LS evaluation used the locomotive syndrome risk test based on LS risk criteria, classifying participants into no risk, stage 1 LS, and stage 2 LS groups. Using a visual analogue scale (VAS), we investigated the prevalence of low back pain (LBP) and assessed physical performances across these groups.

RESULTS

There were 132 participants with no LS risk, 71 with stage 1 LS risk, and 29 with stage 2 LS risk. As LS risk increased, LBP prevalence and VAS scores rose, physical abilities, and back muscle strength decreased. TKA showed no variation across groups, while LLA decreased with advancing LS risk stage. Except for L1-L2 and L5-S1, lumbar disc height (LDH) decreased with higher LS risk stages. LOF occurrence increased notably with higher LS risk stages. Spinal inclination angle (SIA) significantly increased with advancing LS risk stages.

CONCLUSION

Participants diagnosed with LS exhibited an increased incidence of spinal degeneration, reduced LLA, and global spinal imbalance characterized by anterior spinal inclination.

Evaluation of Lower-Limb Kinematics during Timed Up and Go (TUG) Test in Subjects with Locomotive Syndrome (LS) Using Wearable Gait Sensors (H-Gait System)

Few studies have dealt with lower-limb kinematics during the timed up and go (TUG) test in subjects with locomotive syndrome (LS). This study aimed to evaluate the characteristics of lower-limb kinematics during the TUG test in subjects with LS using the wearable sensor-based H-Gait system. A total of 140 participants were divided into the non-LS (n = 28), the LS-stage 1 (n = 78), and LS-stage 2 (n = 34) groups based on the LS risk test. Compared with the non-LS group, the LS-stage 1 and LS-stage 2 groups showed significantly smaller angular velocity of hip and knee extension during the sit-to-stand phase. The LS-stage 2 group showed significantly smaller peak angles of hip extension and flexion during the walking-out phase compared to the non-LS group. These findings indicate that the evaluation of the lower-limb kinematics during the TUG test using the H-Gait system is highly sensitive to detect LS, compared with the evaluation of the lower-limb kinematics when simply walking.

Systemic Chronic Diseases Coexist with and Affect Locomotive Syndrome: The Nagahama Study

OBJECTIVES

The concept of locomotive syndrome was proposed to highlight older adults who require nursing care services due to the malfunctioning of their locomotive organs. With the coming of a super-aging society, there is a growing need to understand relation between systemic chronic diseases and locomotive syndrome.

METHODS

We analyzed the second-visit dataset of the Nagahama Study. The association analysis was performed to identify the chronic diseases that were risk factors associated with the occurrence and the progression of locomotive syndrome in both the cross-sectional and longitudinal studies.

RESULTS

Hypertension, stroke, coronary heart disease, rheumatoid arthritis, chronic renal failure, osteoporosis, anemia, and gastroesophageal reflux disease were independently correlated with locomotive syndrome through the deterioration of body pain, social activity, and cognitive function in the cross-sectional study. Multiple chronic diseases had additive effects and significantly increased the risk of locomotive syndrome. In the longitudinal study, osteoporosis and kidney disease were significantly correlated with the worsening of the total GLFS-25 score.

CONCLUSIONS

Locomotive syndrome coexisted with various systemic chronic diseases, especially cardiovascular diseases. Osteoporosis and kidney disease were significantly correlated with the progression of locomotive dysfunction. The management of various chronic diseases may be useful to prevent locomotive syndrome and vice versa.

A preliminary examination of the association between locomotive syndrome and circulating miRNA-199 in community-dwelling people: The Yakumo study

BACKGROUND

The risk of locomotive syndrome (LS) has been proposed as a criterion for evaluating physical ability. The expression levels of circulating miRNAs (c-miRNAs) are predictors of various diseases. This preliminary study aimed to evaluate the relationship between serum levels of several miRNAs and LS.

METHODS

We enrolled 423 participants in whom we conducted a survey with the 25-question Geriatric Locomotive Function Scale (GLFS-25) and measured the serum levels of 21 c-miRNAs. The relationship between the GLFS-25 and each c-miRNA was evaluated with a linear regression analysis, and independent associations between the GLFS-25 and each c-miRNA were assessed with a multiple regression analysis using various independent variables.

RESULTS

Only the serum level of miR-199 was significantly associated with LS after adjustment for age, BMI, sex, and all comorbidities. The receiver operating characteristics curve for the predictive value of the miR-199 level to indicate the presence or absence of LS risk had an area under the curve (AUC) of 0.576 (95% confidence interval: 0.501-0.651).

CONCLUSION

The expression level of miRNA-199 was associated with the risk of LS in community-dwelling Japanese people.

Association between locomotive syndrome and the Japanese version of the EQ-5D-5L in middle-aged and elderly people in Japan

The Japanese version of the EuroQol 5 dimension, 5 level version (EQ-5D-5L) can now be used to quantitatively evaluate the health-related quality of life (QoL) in Japan. Locomotive syndrome (LS) is a concept advocated in Japan to describe a condition requiring care for musculoskeletal disorders. However, no detailed study on the relationship between this index and LS in Japanese health checkup has been reported. We aimed to evaluate the relationship between the Japanese version of the EQ-5D-5L and LS. We enrolled 477 participants who were undergoing health checkups in Japan. All participants were administered the 25-question Geriatric Locomotive Functional Scale for the diagnosis of LS and the Japanese version of the EQ-5D-5L. We performed statistical analysis to compare the non-LS and LS patients; moreover, the risk factors and cut-off values were calculated and verified. The Japanese version of the EQ-5D-5L index was significantly lower in patients with LS than in non-LS patients and was significantly related to LS in logistic regression analysis. In subgroup analysis targeting the five dimensions of the EQ-5D-5L, it was seen that mobility, pain/discomfort, and self-care were significantly involved in LS. The cut-off value of the EQ-5D-5L index for LS was 0.875. The Japanese version of the EQ-5D-5L index was significantly related to LS in Japan. This index will be a useful tool that can easily measure health-related quality of life in middle-aged and elderly Japanese people. Future studies should investigate the relationship of not only LS but also various diseases with the Japanese version of the EuroQol 5 dimension, 5 level version.

Influence of Global Spine Sagittal Balance and Spinal Degenerative Changes on Locomotive Syndrome Risk in a Middle-Age and Elderly Community-Living Population

Purpose

The aim of this study was to describe the characteristics of each locomotive syndrome (LS) risk stage, including global spine sagittal alignment, spinal degenerative changes evident on plain radiographs, low back pain (LBP), muscle strength, and physical ability in middle-aged and elderly people in a health checkup.

Methods

This study included 211 healthy Japanese volunteers (89 men and 122 women; mean age, 64.0 years) who underwent assessment with both radiographs and Spinal Mouse. Spinal sagittal parameters included thoracic kyphosis angle (TKA), lumbar lordosis angle (LLA), sagittal vertical axis, and spinal inclination angle (SIA). Lumbar disc height (LDH) and lumbar osteophyte formation (LOF) at each level were evaluated as the spinal degenerative changes. The LS assessment comprised three tests: stand-up test, two-step test, and 25-question Geriatric Locomotive Function Scale (GLFS-25). The subjects were divided into three groups (no risk, stage 1 LS, or stage 2 LS) according to LS risk test criteria. The prevalence of LBP was investigated with a visual analogue scale (VAS), and physical performances were also compared among the groups.

Results

Of the participants, 122 had no risk of LS, 56 had stage 1 LS risk, and 29 had stage 2 LS risk. With increasing LS risk stage, the prevalence of and VAS score for LBP increased significantly, and back muscle strength and physical abilities decreased significantly. The TKA did not differ among the three groups. The LLA decreased gradually with LS risk stage (P = 0.0001). At each level except L1–L2 and L5–S1, LDH decreased gradually with LS risk stage. The prevalence of LOF increased significantly with increasing LS risk stage. The SIA increased significantly with LS risk stage (P = 0.0167).

Conclusions

Participants with LS had higher prevalence of spinal degeneration, small LLA, and global spinal imbalance by anterior spinal inclination.

Locomotive syndrome and the power spectral characteristics of body sway

AIM

In Japan, nursing care is advised for patients with locomotive syndrome (LS) because of musculoskeletal disorders. Balance tests have indicated an association between LS risk and sway size related to center of pressure (COP) movement. Here, the power spectrum represents the energy contained in each frequency of COP sway. Although balance tests are often performed during health checkups, no studies have investigated the relationship between the power spectrum and LS. This study investigated this relationship.

METHODS

In total, 605 recipients of health checkups were evaluated for LS using the 25-item Geriatric Locomotive Function Scale. Power spectrums were calculated by applying fast Fourier transform to COP sway time-series data. These were classified into three sections (0.02-0.2 Hz [low-frequency band; LFB], 0.2-2 Hz [mid-frequency band], and 2-10 Hz [high-frequency band; HFB]). Power spectrums were evaluated in left-right and front-back directions.

RESULTS

LS was associated with significantly lower ratios for both the HFB (P = 0.001) in the left-right direction and LFB (P = 0.007) in the front-back direction. In addition, men had significantly lower HFB ratios in the left-right direction (P = 0.032) and LFB ratios in the front-back (P = 0.013), whereas women had significantly lower HFB ratios in the left-right direction (P = 0.007).

CONCLUSIONS

LS was associated with significantly lower ratios for both the HFB in the left-right direction and LFB in the front-back direction. This understanding of the power spectral characteristics of LS may be useful in the context of pathology and therapeutic intervention. Geriatr Gerontol Int ••; ••: ••-•• Geriatr Gerontol Int 2020; ••: ••-••.

Higher extracellular water-to-total body water ratio more strongly reflects the locomotive syndrome risk and frailty than sarcopenia

OBJECTIVE

Among body composition parameters measured by bioelectrical impedance analysis, the extracellular water-to-total body water (ECW/TBW) ratio is a known prognostic or related factor for various diseases. While concepts such as locomotive syndrome risk, frailty, and sarcopenia are gaining popularity in Japan, their relationship with the ECW/TBW ratio has not been examined in detail. This study aimed to investigate the relationships between them.

METHODS

Of 1081 individuals who underwent health checkups, 550 were included in this study. The evaluations included a two-step test, stand-up test, and a 25-question geriatric locomotive function scale questionnaire. Frailty was diagnosed based on the Japanese version of the Cardiovascular Health Study criteria. Sarcopenia was evaluated according to the Asian Working Group for Sarcopenia criteria. The aforementioned ratio was measured using bioelectrical impedance analysis.

RESULTS

The ECW/TBW ratio significantly increased with locomotive syndrome risk, frailty, and sarcopenia (p < 0.001 each). Nevertheless, no significant difference was found between robust and pre-frailty groups (p = 0.71) and normal and pre-sarcopenia groups (p = 0.93). Furthermore, after correcting for age, sex, and body mass index, multiple regression analysis revealed that locomotive syndrome risk (p < 0.001) and frailty (p = 0.001) were significantly associated with an increase in the ECW/TBW ratio, whereas sarcopenia was not (p = 0.97).

CONCLUSIONS

An increase in the ECW/TBW ratio may reflect locomotive syndrome risk and frailty, but not sarcopenia. In bioelectric impedance analysis, this ratio is an important indicator; if it is high, it is necessary to consider locomotive syndrome risk and frailty.

Differences of lumbopelvic sagittal parameters among community-dwelling middle-age and elderly individuals: Relations with locomotor physical function

This study aims to establish radiographic parameters of lumbopelvic sagittal alignment, gender related differences, and age-related changes in a middle-aged community, to investigate whether age-related changes of lumbopelvic alignment reflect the risk of locomotive syndrome (LS). This study included 448 healthy Japanese volunteers who attended a basic health checkup supported by the local government. The subjects (184 males and 264 females, mean age: 62.7 years) were grouped according to their age by decade. Sagittal lumbopelvic parameters were collected by lateral spine radiographs including lumbar lordosis (L1-S1, LL), lower lumbar lordosis (L4-S1, LLL), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). The three tests (stand-up test, two-step test, and 25-question geriatric locomotive function scale [GLFS-25]) composing the LS risk test were performed. LL was significantly lower in males than in the females. A significant decrease of LL and LLL was observed from 60 s to 70 s in the females. PI did not markedly change with aging in either gender but was lower in males. A remarkable increase of PT was seen from 60 s to 70 s in the females. SS did not markedly change with aging and was lower in males in all decades. The prevalence of LS risk in males and females increased gradually with age and was greater in females in any decade. 70 s females with LS risk had significantly lower LL and higher PT compared to them without LS risk. Radiographic parameters of lumbopelvic sagittal alignment were established in community-dwelling middle-age and elderly individuals.

Musculoskeletal Factors and Geriatric Syndromes Related to the Absence of Musculoskeletal Degenerative Disease in Elderly People Aged over 70 Years

Purpose

To investigate factors with a significant relationship with the absence of musculoskeletal disease (MSD: osteoporosis, knee osteoarthritis (K-OA), and lumbar spondylosis (L-OA)) in elderly people ≥70 years old.

Methods

The subjects were 279 people (134 males, 145 females, mean age: 75.2 years) who attended an annual health checkup and were prospectively included in the study. Osteoporosis was defined as %YAM ≤70%, K-OA as Kellgren–Lawrence grade ≥2, and L-OA as osteophytes of Nathan class ≥3. Subjects were divided into those with (group D) and without (group N) any MSD. Clinical variables including locomotive syndrome (LS), frailty, sarcopenia, and QOL (SF-36) were compared between the groups.

Results

There was no significant difference in age or gender between group N (n = 54) and group D (n = 225). Lower BMI and pain, including neuropathic pain; greater back muscle strength, physical ability, and balance with eyes closed; larger lumbar lordosis, sacral inclination, and lumbar ROM; and smaller spinal inclination were found in group N. The rates of LS and sarcopenia were significantly lower and QOL was significantly higher in group N.

Conclusions

This study firstly revealed the significant musculoskeletal factors and geriatric syndromes related to an absence of MSD, which may form the basis of interventions to improve QOL in elderly people ≥70 years old.

Waist Circumference Measured by Bioelectrical Impedance Analysis Is Interchangeable with Manual Measurement: Increased Waist Circumference Is Associated with Locomotive Syndrome Risk

Objectives

The importance of preventive medicine in an aging society is increasing. Locomotive syndrome (LS) is attracting increasing attention. Recently, advances in bioelectrical impedance analysis (BIA) devices have made it possible to automatically measure waist circumference (WC). Nevertheless, there have been no reports evaluating the agreement or interchangeability between WC measured manually and using BIA. Therefore, we aimed to perform these analyses in the context of health checkups and investigated the associations with LS risk.

Methods

We enrolled 597 participants who underwent the following: two-step tests and stand-up tests; evaluations using a 25-question geriatric locomotive function scale for the LS risk test; anthropometric marker measurements including WC measured by manual and BIA; and measurements of total cholesterol and triglycerides. We used Bland–Altman analysis to calculate agreement and interchangeability of the WC measurement using BIA and the manual method. A statistical comparative study was then conducted between normal and LS risk groups. Subsequently, significant risk factors for LS were investigated using multivariate analysis.

Results

The Bland–Altman analysis showed that bias (BIA-manual) was negative overall (−2.024), for males (−1.418) and for females (−2.460), suggesting underestimation using BIA compared with manual measurements. Interchangeability was found between WC measurement by BIA and by manual methods, because the percentage error was less than 15% overall (12.3%), for males (10.2%) and for females (13.8%). Univariate analysis showed that WC was significantly higher in the LS risk group than in the normal group. Multivariate analysis adjusted for confounding factors showed that increase in WC significantly correlated with LS risk.

Conclusions

BIA and manual methods for measuring WC are interchangeable. The increase in WC measured by BIA was significantly associated with LS risk. It is important to continue focusing on increased WC and early detection of LS risk.

Increasing postural sway in balance test is related to locomotive syndrome risk: A cross-sectional study

BACKGROUND

Locomotive syndrome risk level has been recently proposed to evaluate physical ability. Impaired balance control is one of the most important risk factors for falls. However, the relationship between locomotive syndrome risk and postural sway according to the balance test is unclear. This study aimed to investigate the relationship between locomotive syndrome risk and balance test results, including muscle mass and physical function, in a large-scale prospective general health checkup.

METHODS

We enrolled 292 participants who underwent a basic health checkup and conducted a two-step test, stand-up test, evaluation using a 25-question geriatric locomotive function scale for the locomotive syndrome risk test, balance test, appendicular skeletal muscle mass measurement by bioelectrical impedance analysis, evaluation of physical function by the timed-up-and-go test, and back muscle and grip strength evaluation. A statistical comparative study was then conducted between normal and locomotive syndrome risk groups. Subsequently, significant factors for locomotive syndrome risk were investigated by multivariate analysis.

RESULTS

The comparative study was conducted by adjusting age and sex using a generalized linear model. No significant difference in muscle mass existed, but postural sway in the balance test significantly increased in the people at locomotive syndrome risk. Among the four posturographic variables by balance test, increase in back-and-forth sway was the most remarkable variable associated with locomotive syndrome risk together with back muscle strength, body mass index, and the timed-up-and-go test by logistic regression analysis. This posturographic variable was significantly related to the timed-up-and-go test and leg skeletal muscle mass by multiple regression analysis.

CONCLUSIONS

A relationship was recognized between locomotive syndrome risk and postural sway. In particular, increase in back-and-forth sway was an important factor for locomotive syndrome risk. If the balance test shows an increase in back-and-forth sway, attention should be paid to locomotive syndrome risk for possible intervention and early treatment.

The decreasing phase angles of the entire body and trunk during bioelectrical impedance analysis are related to locomotive syndrome

BACKGROUND

The phase angle (measured via bioelectrical impedance analysis [BIA]) is an indicator of cell membrane function and used for prognostic evaluation of diseases. Locomotive syndrome (LS) has been advocated in the evaluation of physical ability. This study aimed to determine the relationship between LS and the phase angle as well as muscle mass, muscular strength, and motor function.

METHODS

In this prospective cohort study, 541 patients undergoing a health checkup participated. All participants were assessed using a 25-question geriatric locomotive function scale for the diagnosis of LS, phase angle, and muscle mass measurements via BIA. Grip strength, back muscle strength, and 3-m timed-up-and-go (TUG) test measurements were used as physical performance tests. Patients were divided into non-LS and LS groups, and their characteristics were compared. We assessed whether the phase angle was related to LS, whether it could be a risk factor in multivariate analysis, and the most important part of the phase angle.

RESULTS

Age, the whole body phase angle, grip strength, back muscle strength, and TUG test result were significantly different between the two groups. Logistic regression analysis revealed that the whole body phase angle and TUG test result were risk factors of LS. Based on the subanalysis targeting specific phase angles, the trunk phase angle was a significant important factor for LS.

CONCLUSION

The phase angle was significantly related to LS, and the decreased phase angle was a significant risk factor of LS together with the TUG test result. Furthermore, in subgroup analysis, the phase angle of the trunk was a significant important factor of LS. BIA can be performed conveniently, and it has been widely used for health checkups and in clinical practice. Focusing on the phase angle in BIA may be additionally helpful for the early detection and early intervention of LS.

Declining neck circumference is an anthropometric marker related to frailty in middle-aged and elderly women

Objectives: Neck circumference (NC) has been associated with cardiovascular disease and metabolic syndrome. However, the association between NC and frailty remains unknown. We aimed to determine the relationship between frailty and NC in middle-aged and elderly women.Methods: Frailty was diagnosed based on the Japanese version of the Cardiovascular Health Study criteria. Of women who underwent health checkup, 295 women with the following measurements were targeted: four trunk circumferences and appendicular skeletal muscle index (aSMI) measured using bioelectrical impedance analysis; albumin, total cholesterol, triglycerides, and C-reactive protein levels measured using a blood test; and physical function measured using back muscle strength and timed up-and-go test (TUG). Normal and frailty group comparisons were conducted using a statistical method.Results: Significant differences were observed between the two groups in terms of age, body mass index, all trunk circumferences, aSMI, back muscle strength, and TUG. Logistic regression analysis showed that NC was more related with frailty among the four trunk circumferences. In multiple regression analysis, declining NC was significantly associated with frailty.Conclusion: In middle-aged and elderly women, NC has a significant association with frailty. Declining NC was shown to be an anthropometric marker of frailty, and may be a frailty risk factor.

Shoulder pain has most impact on poor quality of life among various types of musculoskeletal pain in middle-aged and elderly people: Yakumo study

Objectives: To investigate the severity and effect on quality of life (QOL) of various types of pain in healthy volunteers.Methods: A total of 384 subjects (male: 158, female: 226, average age: 63 years) were included in a prospective cohort study (Yakumo study). Shoulder pain, low back pain (LBP), sciatica, knee pain, and the American Shoulder and Elbow Surgeons (ASES) shoulder score were evaluated with SF-36.Results: The prevalence of shoulder pain, LBP, sciatica, and knee pain was 42%, 44%, 16%, and 48%, respectively, with similar severities of pain. Shoulder pain visual analogue scale (VAS) and ASES shoulder scores were significantly correlated with SF-36 domains. Subjects with poor physical QOL had significantly higher VAS scores for all pain types and a lower ASES shoulder score. Shoulder pain VAS was also significantly related to poor mental QOL. Multivariate regression analysis adjusted for age and gender showed that shoulder pain VAS (OR: 1.25, p < .05) and 10-m gait speed (OR: 1.82, p < .05) were significant independent risk factors for poor physical QOL.Conclusion: Only shoulder pain of similar severity to other pain and shoulder complaints impacted on both physical and mental QOL. The severity of shoulder pain was an independent risk factor for poor physical QOL.

Low Bioelectrical Impedance Phase Angle Is a Significant Risk Factor for Frailty

The phase angle, which is measured via bioelectrical impedance analysis (BIA), is a clinically important bioimpedance parameter used for nutritional assessment and evaluating the risk of various diseases, such as locomotive syndrome (LS). It remains unclear if the phase angle is associated with frailty (fragile state of physical and mental health). We therefore examined this association in a large prospective sample. Of 1081 individuals receiving health checkups, 550 (male; 235, female; 365) were enrolled in this study. We applied the Japanese version of the Cardiovascular Health Study criteria to evaluate frailty and administered the 25-Item Geriatric Locomotive Function Scale to diagnose LS. The phase angle was measured via BIA. Multiple logistic regression analysis was used to evaluate the relationship between the phase angle and frailty. For all participants and for each sex, the phase angle was significantly lower among individuals with frailty. After controlling for age, sex, and body mass index, we found that a low phase angle was a significant risk factor of frailty. As a result of multiple regression analysis including other confounding factors, among male participants, a low phase angle was significantly related with both frailty (P = 0.015) and LS (P < 0.001), whereas among female participants, the low phase angle had a stronger association with frailty (P = 0.001) than with LS (P = 0.52). Our findings suggest that a low angle is a risk factor of frailty. Furthermore, among female participants, frailty has a stronger relation with the phase angle than does LS. Therefore, the phase angle may be considered a useful indicator of frailty that does not require lengthy or costly assessment.

Utility of the Serum Cystatin C Level for Diagnosis of Osteoporosis among Middle-Aged and Elderly People

Purpose

Osteoporosis is a common age-related disorder leading to increased bone fragility and risk of fracture. Early diagnosis of osteoporosis is a vital step in providing early therapeutic intervention. Serum cystatin C is a marker of early renal dysfunction, a predictor of cardiovascular and inflammatory diseases, and an inhibitor of the differentiation of osteoclast precursor cells. The purpose of this study was to evaluate the relationship between serum cystatin C and osteoporosis.

Methods

We enrolled 46 subjects who attended a health checkup and underwent measurement of bone status by quantitative ultrasound and determination of the level of serum cystatin C. A comparative study was conducted between those with and without osteoporosis for all subjects collectively and in two subgroups aged <65 and ≥65 years.

Results

Serum cystatin C levels were strongly correlated with age, creatinine, and bone status data, with significant negative correlations with stiffness, T-score, and percentage of young adult mean. Among patients with osteoporosis, serum cystatin C was significantly higher even after adjustment for age and sex, whereas no significant difference was noted in creatinine. For patients aged ≥ 65 years, serum cystatin C was significantly higher in subjects with osteoporosis, although there was no significant difference in age between normal subjects and those with osteoporosis.

Conclusions

To the best of our knowledge, this is the first study to demonstrate an association between serum cystatin C and osteoporosis. Serum cystatin C is significantly higher in osteoporosis and in particular may be a useful marker for osteoporosis among middle and elderly people aged ≥ 65 years. Measurement of serum cystatin C can be carried out easily and may contribute to early diagnosis and treatment of osteoporosis.