Low serum 25-hydroxyvitamin D levels associated with falls among Japanese community-dwelling elderly

Vitamin D, C-Reactive Protein, and Increased Fall Risk: A Genetic Epidemiological Study

Background: Falls are a major public health concern. Daily vitamin D supplementation is a proposed fall prevention strategy; however, safety concerns have arisen from some clinical trials showing increased fall risk when using higher vitamin D dosing methods. The relationship between vitamin D and falls may be influenced by factors, such as inflammation, which can alter the balance of essential nutrients like vitamin D and retinol, potentially affecting motor function. We use a genetic epidemiological approach to explore the association of inflammation, vitamin D, and fall risk. Methods: We included 307,082 UK Biobank participants and conducted observational and Mendelian randomization (MR) analyses to investigate associations between 25-hydroxyvitamin D [25(OH)D] and fall risk, with analyses including restriction to participants who had fallen and had inflammation as defined by CRP ≥ 5 mg/L. Results: In the observational analysis, CRP was associated with a higher (per 5 mg/L CRP increase OR = 1.06, 95% CI 1.05-1.07) and 25(OH)D with a lower odds of falls. The association between 25(OH)D concentrations and fall risk was non-linear (p < 0.001), reflecting a plateauing of the association at higher concentrations. There was an interaction between 25(OH)D and CRP on their association with the odds of falls (p = 0.009). In participants with CRP ≥ 5 mg/L, the association was U-shaped, and the fall risk was elevated for both 25(OH)D < 25 nmol/L and ≥ 100 nmol/L (p < 0.004). The association between high 25(OH)D and falls was most pronounced for participants with CRP ≥ 20 mg/L (≥ 100 nmol/L vs. 50-74.99 nmol/L: OR = 2.40, 95% CI, 1.50-3.86). Genetically predicted higher 25(OH)D was not associated with fall risk in the overall population, but a suggestive association with fall risk was seen in participants who had fallen and had CRP > 20 mg/L (926 cases; OR = 1.20, 95% CI, 1.00-1.44). Conclusions: Our study suggests that inflammation might modify the vitamin D and fall risk relationship. Both low and high 25(OH)D levels are associated with more falls in individuals with chronic inflammation, with supporting evidence seen in both observational and MR analyses. This may provide insight into the increased fall risk following high-dose vitamin D supplementation in clinical trials, warranting further research.

The relationships of serum vitamin D concentration with linear speed and change of direction performance in soccer players

The aim of the study was to establish whether the level of 25 hydroxyvitamin D (25(OH)D) in serum has an influence on speed (m/s) and change of direction (COD, s) performance. Twenty male soccer players from the top league participated in the study. All subjects were evaluated for the serum concentration of 25(OH)D at the beginning of the preseason. The linear sprint test was performed at 5 m and 30 m, and COD (time and deficit) at the beginning (BPP) and after (APP) 6 weeks of the preparatory period. The results revealed that 20% of soccer players had a significant deficiency of 25(OH)D (<20 ng/mL) and 30% had insufficient 25(OH)D levels (between 20 and 30 ng/mL). Positive correlations were found between the training effect for the ∆COD (BPP-APP) (p = 0.003) and ∆deficit (BPP-APP) (p = 0.039). Significant differences were noticed for the ∆COD (m = 0.60 [s]) and ∆deficit (m = 0.56[s]) in the soccer players whose 25(OH)D concentration was <=30 ng/mL, and for the ∆COD (p = 0.002) and ∆deficit (p = 0.017) in the soccer players whose 25(OH)D concentration was >30 ng/mL. The training effect was significantly higher for the soccer players whose 25(OH)D concentration was above 30 ng/mL. Soccer players with higher 25(OH)D levels achieved superior results in the COD test and demonstrated better deficit outcomes, affirming the positive influence of 25(OH)D on muscle metabolism.

Association between serum vitamin D levels and skeletal muscle indices in an older Japanese population: The SONIC study

AIM

Vitamin D (VD) affects skeletal muscles. The high prevalence of VD deficiency in Japan may lead to decreased skeletal muscle mass and strength, increasing the prevalence of sarcopenia. Therefore, we aimed to investigate the association between serum VD levels and skeletal muscle indices in a Japanese community-dwelling older population.

METHODS

We extracted data from the Septuagenarians, Octogenarians, Nonagenarians Investigation with Centenarians (SONIC) study. We analyzed the data for participants in the 70s and 90s age groups. Skeletal mass index (SMI) using bioimpedance analysis, grip strength, walking speed, and serum VD levels using 25-hydroxyvitamin D [25(OH)D] were measured.

RESULTS

We analyzed the data of 310 participants in their 70s and 48 in their 90s. Mean serum 25(OH)D levels were 21.6 ± 5.0 ng/mL in the 70s group and 23.4 ± 9.1 ng/mL in the 90s group. In the 70s group, serum 25(OH)D levels correlated with SMI (r = 0.21, P < 0.0001) and grip strength (r = 0.30, P < 0.0001). Serum 25(OH)D levels were independently associated with SMI after adjusting for sex, body mass index, and serum albumin levels. In the 90s group, serum 25(OH)D levels were correlated with SMI (r = 0.29, P = 0.049) and grip strength (r = 0.34, P = 0.018). However, the multivariate analysis showed no independent association between SMI, grip strength, and serum 25(OH)D levels.

CONCLUSION

In a cross-sectional analysis of an older population, serum VD levels were associated with SMI and grip strength, and this association was more pronounced in the 70s group than in the 90s group. Our results suggest that serum VD levels maintain skeletal muscle mass and grip strength. Geriatr Gerontol Int 2024; 24: 898-903.

Evaluation of Nutrition and Performance Parameters in Division 1 Collegiate Athletes

BACKGROUND

Testing and evaluating athletes is necessary and should include performance, body composition, and nutrition. The purpose of this study was to report assessments of dietary intake, V˙O2max, and body composition in D1 collegiate athletes and examine relationships between these assessments.

METHODS

Dietary intake was assessed with 3-day recalls and compared to recommendations, and body composition was assessed via bioelectrical impedance analysis (BIA) (n = 48). V˙O2max was evaluated using a graded exercise test (GXT) with a verification bout (n = 35). Reliability between "true" V˙O2max and verification was determined. Correlations and regressions were performed.

RESULTS

Energy, carbohydrate, and micronutrient intake was lower than recommendations. Mean V˙O2max was 47.3 and 47.4 mL·kg-1·min-1 for GXT and verification, respectively. While correlations were apparent among dietary intake, V˙O2max, and body composition, percent fat-free mass (%FFM) predicted 36% of V˙O2max.

CONCLUSIONS

Collegiate athletes are not meeting energy and carbohydrate recommendations and exceed fat recommendations. Vitamin D and magnesium were low in all sports, and iron and calcium were low in females. V˙O2max ranged from 35.6 to 63.0 mL·kg-1·min-1, with females below average and males meeting typical values for their designated sport. Assessing D1 athletes can provide guidance for sports dietitians, coaches, and strength and conditioning specialists to track and monitor nutrition in athletes.

High serum 25-hydroxyvitamin D levels are associated with greater lean tissue mass and skeletal muscle mass:a cross-sectional study on young healthy Japanese women

Studies have shown that low serum 25(OH)D levels in young women may affect not only their own health but also the health of next generation through pregnancy and childbirth. The aim of this study is to assess the serum 25(OH)D levels in young Japanese women and to determine the factors influencing the changes in their serum 25(OH)D levels. Herein, 83 healthy young Japanese women were included. Early morning fasting blood samples, habitual food intake survey, eating habits survey, and anthropometric measurements were used to analyze the relationship between the serum 25(OH)D levels and nutrient intake, intake of food groups, dietary habits, and body composition. The findings revealed that about 50% of the study participants had an adequate intake (AI) of vitamin D (8.5 µg), whereas about 88% of the study participants were vitamin D deficient and about 12% were insufficient in serum 25(OH) levels. No significant association was observed between the serum 25(OH)D levels and nutrient intake or intake of food groups. Furthermore, higher serum 25(OH)D levels were associated with higher percentages of muscle and lean tissue, indicating that regulating the serum 25(OH)D levels helps maintain muscle mass and lowers the risk of sarcopenia and locomotive syndrome. J. Med. Invest. 71 : 260-266, August, 2024.

Interaction of estradiol and vitamin D with low skeletal muscle mass among middle-aged and elderly women

BACKGROUND

Since the connection between muscle atrophy and vitamin D and estradiol status ambiguous, this study was thus conducted to determine whether low skeletal muscle mass (SMM) in middle-aged and elderly women was affected by estradiol and vitamin D levels together.

METHODS

Baseline data from a sub-cohort of the China Northwest Natural Population Cohort: Ningxia Project (CNC-NX) were analyzed. Serum 25-hydroxyvitamin D (25(OH) D) and estradiol were measured by chemiluminescence immunoassay analyzer. Bivariate logistic regression and multiplicative interaction analyses were used to assess the impact of estradiol level and vitamin D status on low SMM, as well as the combined impact of estradiol and low vitamin D status on low SMM.

RESULTS

A total of 287 (9.49%) participants had low SMM, which had lower levels of estradiol and vitamin D concentration than normal SMM group. While, after adjusting the confounding variables, these correlations were maintained in estradiol Q1, Q2, Q3 and vitamin D Q1. Furthermore, the significant combined effect of the highest quartile of estradiol concentrations and non-vitamin D deficiency, and interactions between vitamin D Q1 and estradiol Q2, vitamin D Q1 and estradiol Q3, vitamin D Q2 and estradiol Q1, vitamin D Q3 and estradiol Q3 on low SMM were stably reflected (P for interaction < 0.05).

CONCLUSIONS

Estradiol and vitamin D were interrelated with low SMM in middle-aged and elderly women. Combination of estradiol and vitamin D supplements should be encouraged for middle-aged and elderly women who are at risk of muscle atrophy or experiencing muscle atrophy.

Usefulness of Vitamin D Deficiency Questionnaire for Japanese (VDDQ-J) for Screening of Vitamin D Deficiency and Low Muscle Mass in Relatively Healthy Japanese Anti-Aging Health Checkup Examinees

The Vitamin D Deficiency Questionnaire for Japanese (VDDQ-J) has been developed as an alternative indicator of the vitamin D nutritional status when serum 25(OH)D measurement is unavailable. In the present study, we compared the usefulness of the VDDQ-J with that of serum 25(OH)D concentration and examined the relationship among vitamin D, DXA-based body composition, and muscle strength in 163 anti-aging health check examinees. The median age, 25(OH)D concentration and VDDQ-J score were 62.0 y, 20.1 ng/mL and 22.0 points, respectively. In total, 47.9% of the subjects had serum 25(OH)D concentrations of <20 ng/mL. The VDDQ-J score was significantly negatively correlated with the serum 25(OH)D concentration, and the positive predictive value for vitamin D deficiency was 86.3%. The prevalence of sarcopenia was 6.1%. Low 25(OH)D levels and high VDDQ-J scores were significantly associated with low muscle mass in both univariate analysis and multiple linear regression analysis. The serum 25(OH)D level showed a significant negative correlation with body fat mass. The VDDQ-J score was selected as a significant determinant of low skeletal muscle mass index (<7.0 kg/m2 for men and <5.4 kg/m2 for women) by a multiple logistic regression analysis. In conclusion, the present study showed that a low vitamin D nutritional status as indicated by both low 25(OH)D levels, and high VDDQ-J scores was associated with low muscle mass and the VDDQ-J is considered useful not only for the detection of vitamin D deficiency but also in the screening of individuals with low muscle mass and a high risk of sarcopenia.

Influence of vitamin D on sarcopenia pathophysiology: A longitudinal study in humans and basic research in knockout mice

BACKGROUND

Vitamin D is an essential nutrient in musculoskeletal function; however, its relationship to sarcopenia remains ambiguous, and the mechanisms and targets of vitamin D activity have not been elucidated. This study aimed to clarify the role of vitamin D in mature skeletal muscle and its relationship with sarcopenia.

METHODS

This epidemiological study included 1653 community residents who participated in both the fifth and seventh waves of the National Institute for Longevity Sciences, Longitudinal Study of Aging and had complete background data. Participants were classified into two groups: vitamin D-deficient (serum 25-hydroxyvitamin D < 20 ng/mL) and non-deficient (serum 25-hydroxyvitamin D ≥ 20 ng/mL); they underwent propensity-score matching for background factors (age, sex, height, weight, comorbidities, smoker, alcohol intake, energy intake, vitamin D intake, steps, activity, season and sarcopenia). Changes in muscle strength and mass over the 4-year period were compared. For basic analysis, we generated Myf6^CreERT2 Vitamin D Receptor (VDR)-floxed (Vdr^mcKO ) mice with mature muscle fibre-specific vitamin D receptor knockout, injected tamoxifen into 8-week-old mice and analysed various phenotypes at 16 weeks of age.

RESULTS

Grip strength reduction was significantly greater in the deficient group (-1.55 ± 2.47 kg) than in the non-deficient group (-1.13 ± 2.47 kg; P = 0.019). Appendicular skeletal muscle mass reduction did not differ significantly between deficient (-0.05 ± 0.79 kg) and non-deficient (-0.01 ± 0.74 kg) groups (P = 0.423). The incidence of new cases of sarcopenia was significantly higher in the deficient group (15 vs. 5 cases; P = 0.039). Skeletal muscle phenotyping of Vdr^mcKO mice showed no significant differences in muscle weight, myofibre percentage or myofibre cross-sectional area; however, both forelimb and four-limb muscle strength were significantly lower in Vdr^mcKO mice (males: forelimb, P = 0.048; four-limb, P = 0.029; females: forelimb, P < 0.001; four-limb, P < 0.001). Expression profiling revealed a significant decrease in expression of sarcoendoplasmic reticulum Ca²⁺ -ATPase (SERCA) 1 (P = 0.019) and SERCA2a (P = 0.049) genes in the Vdr^mcKO mice. In contrast, expression of non-muscle SERCA2b and myoregulin genes showed no changes.

CONCLUSIONS

Vitamin D deficiency affects muscle strength and may contribute to the onset of sarcopenia. Vitamin D-VDR signalling has minimal influence on the regulation of muscle mass in mature myofibres but has a significant influence on muscle strength.

A prospective analysis of concentration of 25-OHD between northern and southern district in Japan in year-round study

Although osteoporotic patients have already been recognized as having a low-volume vitamin D status, the concentration of active vitamin D precursor has not been studied in detail. This trial aimed to clarify the concentration of 25-hydroxyvitamin D (25-OHD), which is a natural type of vitamin D and compare between 2 separate areas in Japan. To compare and clarify the concentration of 25-OHD between 2 separate areas, Japanese patients who were diagnosed as having osteoporosis based on bone mineral density were studied. We analyzed 2 different hospitals' patients whose residence is separated into a northern district (Akita city: north latitude 39" 43') and a southern district (Shizuoka city: north latitude 34" 58'). Both of them have completely different daylight hours. Three-hundred sixty eight patients (174 in Akita, 194 in Shizuoka) were enrolled in this trial to compare the differences of concentration of 25-OHD by Welch's t t-test. There were significant differences in the concentration of 25-OHD and age between them. Akita patients were significantly higher than that of Shizuoka patients despite Shizuoka having much daylight hours of Akita. In conclusion, there might be no relationship between the concentration of 25 OHD and exposure to sunlight.

The Relationship Between Vitamin D and Activity of Daily Living in the Elderly

Objective

To analyze the association between vitamin D and the performance of activity of daily living in the elderly.

Methods

A total of 94 patients over the age of 65 were eligible to participate if they had undergone a bone mineral density test and if they were in a stable health condition. Subjects were further divided into two groups according to activity of daily living (ADL): the score over 40 of the patients as the high ADL group and the below as the low ADL group.

Results

According to univariate analysis, the mean of total hip T score, serum creatinine/cystatin C ratio (CCR), and vitamin D were significantly different between the two groups (P=0.024, 0.008, 0.010). Multivariate ORs showed that the CCR (OR: 0.948; 95%CI: 0.910–0.989; P=0.013) and vitamin D (OR: 865; 95%CI: 0.752–0.994; P=0.047) were inversely associated with having low ADL. Furthermore, on multiple linear regression analysis, the Barthel ADL index was related to geriatric nutritional risk index (GNRI), CCR and vitamin D but independent of patients’ age with the slope of 0.732, 0.539, and 0.689 separately, reflected the stronger relative within the variables.

Conclusion

We demonstrated that there is a negative correlation of CCR and vitamin D with having low ADL in elderly population. Monitoring the trend of serum vitamin D and CCR, may have a role in the early detection of low ADL with loss of muscle mass and strength in the population of the elderly.

Association between Neutrophil-to-Lymphocyte Ratio and Physical Function in Older Adults: A Community-Based Cross-Sectional Study in Japan

Inflammatory responses contribute to physical decline in older adults. Clinical studies have shown that the neutrophil-to-lymphocyte ratio (NLR), a marker of inflammation, is associated with physical decline. However, its association with physical function in community-dwelling older people is still unclear. Hence, we used cross-sectional data to investigate the relationship between NLR and physical function in community-dwelling older adults. Specifically, we analyzed data corresponding to 818 individuals (336 men and 482 women) aged ≥ 75 years, all of whom participated in comprehensive health examinations, including face-to-face interviews, biochemical analyses, and physical function tests. Using these data, we performed multivariable logistic regression analysis to assess the relationship between NLR and physical function, adjusting for sex, age, education, alcohol consumption, smoking, instrumental activity of daily living, body mass index, chronic disease, physical activity, serum albumin level, and depressive mood. The results showed that a higher NLR was associated with a lower grip strength, lower knee extension strength, and slower walking speed. Importantly, the relationship between NLR and physical function was maintained after adjusting for the confounding factors. Thus, we showed a significant association between NLR and physical function, supporting the use of NLR as a marker of physical function in community-dwelling older adults.

Influences of Vitamin D and Iron Status on Skeletal Muscle Health: A Narrative Review

There is conflicting evidence of the roles vitamin D and iron have in isolation and combined in relation to muscle health. The purpose of this narrative review was to examine the current literature on the roles that vitamin D and iron have on skeletal muscle mass, strength, and function and how these nutrients are associated with skeletal muscle health in specific populations. Secondary purposes include exploring if low vitamin D and iron status are interrelated with skeletal muscle health and chronic inflammation and reviewing the influence of animal-source foods rich in these nutrients on health and performance. PubMed, Scopus, SPORT Discus, EMBAE, MEDLINE, and Google Scholar databases were searched to determine eligible studies. There was a positive effect of vitamin D on muscle mass, particularly in older adults. There was a positive effect of iron on aerobic and anaerobic performance. Studies reported mixed results for both vitamin D and iron on muscle strength and function. While vitamin D and iron deficiency commonly occur in combination, few studies examined effects on skeletal muscle health and inflammation. Isolated nutrients such as iron and vitamin D may have positive outcomes; however, nutrients within food sources may be most effective in improving skeletal muscle health.

The Vitamin D/Vitamin D receptor (VDR) axis in muscle atrophy and sarcopenia

Muscle atrophy and sarcopenia (the term given to the age-related decline in muscle mass and function), influence an individuals risk of falls, frailty, functional decline, and, ultimately, impaired quality of life. Vitamin D deficiency (low serum levels of 25-hydroxyvitamin D (25(OH)D₃)) has been reported to impair muscle strength and increase risk of sarcopenia. The mechanisms that underpin the link between low 25(OH)D₃ and sarcopenia are yet to be fully understood but several lines of evidence have highlighted the importance of both genomic and non-genomic effects of active vitamin D (1,25-dihydroxyvitamin D (1,25(OH)₂D₃)) and its nuclear vitamin D receptor (VDR), in skeletal muscle functioning. Studies in vitro have demonstrated a key role for the vitamin D/VDR axis in regulating biological processes central to sarcopenic muscle atrophy, such as proteolysis, mitochondrial function, cellular senescence, and adiposity. The aim of this review is to provide a mechanistic overview of the proposed mechanisms for the vitamin D/VDR axis in sarcopenic muscle atrophy.

Analytical, experimental and clinical aspects of total 25-hydroxyvitamin D measurement by two ligand assays are differentially biased by disease-related factors

BACKGROUND

Pathological concentrations of plasma proteins may confound the results of binding assays. We compared two routinely used total 25-hydroxyvitamin D [t-25(OH)D] methods: a chemiluminescence-immuno-(CLIA) and an electro-chemiluminescence-protein-binding-(ECLPBA) assay.

METHODS

Two sub-studies were performed: 1) In an "in vitro" study, exogenous albumin was added to pools of patients' sera with low albumin levels; and 2) In "ex vivo" studies of Cohort_1: sera of hospitalized patients with low albumin levels, and of healthy controls; and of Cohort_2: outpatients with chronic kidney disease in pre-dialysis stage, or on peritoneal dialysis and hemodialysis were investigated by the routine and LC_MS/MS methods.

RESULTS

When increasing albumin concentrations were "in vitro" added, t-25(OH)D levels were overestimated by ECLPBA, and underestimated by CLIA. In patients' sera, positive correlations were detected between t-25(OH)D-vitamin D binding protein (DBP) values by both routine methods, and between t-25(OH)D-albumin values by all three methods. Much higher t-25(OH)D was measured by LC_MS/MS in all subgroups. When altering albumin levels with constant DBP concentration, the "in vitro" experiment revealed a higher sensitivity of ECLPBA. The "ex vivo" measurements demonstrated clinically relevant differences between the routine methods.

CONCLUSION

Both routine methods are dependent of the matrix effect in hospitalized patients, which is predicted by the DBP/Albumin ratios. In hemodialysis, ECLPBA is recommended because its outcomes differ less from those of LC_MS/MS. The results of LC_MS/MS are reliable, but not routinely available. A guidance would be valuable on how levels measured by the binding methods differ from those by LC-MS/MS in various clinical conditions.

Early adverse events after the first administration of zoledronic acid in Japanese patients with osteoporosis

INTRODUCTION

The occurrence of early adverse events and the factors associated with these events in zoledronic acid-treated Japanese patients with osteoporosis were investigated.

MATERIALS AND METHODS

All patients treated with zoledronic acid for the first time for primary osteoporosis were analyzed. Based on the history of bisphosphonate (BP) administration, the patients were divided into three groups: BP-switch, BP-washout, and naïve groups. The BP-washout and naive groups were combined into a non-BP group.

RESULTS

A total of 184 patients with a mean age of 77.4 years were included. Acute phase reactions (APRs) occurred in 32 patients (17.4%). The significant risk factors were hospitalization (vs. outpatients), BP-switch (vs. non-BP), and age > 80 years (vs. ≤ 69 years), and the odds ratios were 5.63, 0.12, and 0.23, respectively. The serum calcium levels were significantly reduced in the non-BP group, regardless of the co-administration of active vitamin D₃. However, the patients who were co-administered active vitamin D₃ had significantly higher values than those who were not. In the BP-switch group, no significant reduction in serum calcium levels was observed; however, the reductions tended to be smaller in the patients who were co-administered active vitamin D₃.

CONCLUSION

Occurrence of APRs might be lesser in clinical practice than in phase 3 clinical trials. Although serum calcium levels decreased in many cases, the decrease could be suppressed by the co-administration of active vitamin D₃.

Effect of Vitamin D Supplementation on Skeletal Muscle Volume and Strength in Patients with Decompensated Liver Cirrhosis Undergoing Branched Chain Amino Acids Supplementation: A Prospective, Randomized, Controlled Pilot Trial

BACKGROUND

Sarcopenia worsens patient prognoses in chronic liver disease. This study aimed to elucidate the effects of vitamin D supplementation on skeletal muscle volume and strength in patients with decompensated cirrhosis.

METHODS

Thirty-three patients were entered into the study based on the criteria and then randomly assigned to two groups: Group A (n = 17), the control group, and Group B (n = 16), those who received oral native vitamin D3 at a dose of 2000 IU once a day for 12 months.

RESULTS

SMI values in Group B were significantly increased at 12 months (7.64 × 10^-3). The extent of changes in the SMI and grip strength in Group B were significantly greater than that in Group A at 12 months (p = 2.57 × 10^-3 and 9.07 × 10^-3). The median change rates in the SMI were +5.8% and the prevalence of sarcopenia was significantly decreased from 80.0% (12/15) to 33.3% (5/15; p = 2.53 × 10^-2) in Group B.

CONCLUSIONS

Vitamin D supplementation might be an effective and safe treatment option for patients with decompensated cirrhosis to increase or restore the skeletal muscle volume and strength or prevent the muscle volume and strength losses.

Urinary pentosidine level is associated with grip strength and gait speed in community-dwelling adults: a cross-sectional study

Background

Muscle and bone interactions might be associated with osteoporosis and sarcopenia. Urinary pentosidine and serum 25-hydroxyvitamin D (25(OH)D) might affect muscle and bone interactions. It is unclear whether these biomarkers are affected by age and sex or play a role in muscle and physical functions. We aimed to investigate the association between urinary pentosidine and serum 25(OH)D levels with muscle mass, muscle strength, and physical performance in community-dwelling adults.

Methods

Two-hundred and fifty-four middle-aged and elderly adults were enrolled. There was no significant difference in age between 97 men (75.0 ± 8.9 years) and 157 women (73.6 ± 8.1 years). The skeletal muscle mass index (SMI), grip strength, and gait speed were assessed. The urinary pentosidine level was measured. We evaluated the association of urinary pentosidine and serum 25(OH)D levels with age and sex (student’s t-test) and correlations between biomarker and each variable (Pearson’s correlation coefficients). Multiple regression analysis was performed with grip strength and gait speed as dependent variables and with age, height, weight, body mass index (BMI), speed of sound (SOS), SMI, glycated hemoglobin (HbA1c), estimated glomerular filtration rate (eGFR), 25(OH)D, and pentosidine as independent variables using the stepwise method.

Results

The urinary pentosidine level was negatively correlated with grip strength, gait speed, eGFR, and insulin-like growth factor-1 (IGF-1) in men and with SOS, grip strength, and gait speed in women. The serum 25(OH)D level was positively correlated with IGF-1 in women and grip strength in men. Grip strength was associated with age, height, and pentosidine in men and height and pentosidine in women. Gait speed was associated with age, BMI, and pentosidine in men and age, height, and pentosidine in women.

Conclusion

Urinary pentosidine levels are significantly associated with grip strength and gait speed and may serve as a biomarker of muscle and bone interactions.

The serum 25(OH)D level and hand grip strength for fall risk assessment among osteoporotic elderly Japanese women

We investigated the relationship between serum 25(OH)D levels, grip strength, and fall score in elderly osteoporotic women for fall risk assessment. Both low serum 25(OH)D and low grip strength were independently associated with increased fall risk. The serum 25(OH)D cutoff specific to increased fall risk was 14 mg/dL (35 nmol/L).

PURPOSE

This study aimed to establish a cutoff value of serum 25-hydroxyvitamin D (25(OH)D) for fall assessment and investigate the relationship between serum 25(OH)D, grip strength, and fall score adjusted for age in osteoporotic elderly Japanese women.

METHODS

This is a cross-sectional study utilizing collected data of osteoporotic elderly (age ≥65 years) female patients. A questionnaire for fall risk assessment was used, in which a score ≥ 6 was determined as increased fall risk. Serum 25(OH)D levels and grip strength were measured, and the cutoff points were calculated by receiver operating curve (ROC) analysis. Logistic regression analysis with age adjustment was conducted for potential risk factors for fall.

RESULTS

After applying eligibility criteria, finally, 349 patients were enrolled. The median patient age was 77.0 years, and the mean serum 25(OH)D level was 15.6 ng/mL (36 nmol/L). Based on the ROC analysis, we defined the cutoff values of serum 25(OH)D level and grip strength as 14 ng/mL (35 nmol/L) and 15 kg, respectively. A multivariate analysis adjusted for age was conducted. Low serum 25(OH)D level and grip strength were independent risk factors for ≥6 fall risk scores.

CONCLUSION

Both low serum 25(OH)D level and low grip strength were independently associated with increased fall risk score in osteoporotic elderly women. The appropriate serum 25(OH)D cutoff specific to the increased fall risk group in this population was 14 mg/dL (35 nmol/L). These findings might be used for the identification of patients with high fall risks. These results should be confirmed in other patient groups.

Prevalence of Vitamin D Insufficiency and Deficiency in Young, Female Patients With Lower Extremity Musculoskeletal Complaints

BACKGROUND

Low levels of vitamin D have well-known impacts on bone health, but vitamin D also has a more global role throughout many tissues, including skeletal muscle. The high prevalence of hypovitaminosis D and the vast physiological features of vitamin D have led researchers to examine the influence of vitamin D on physical performance and injury. Because of the critical role of vitamin D in maintaining musculoskeletal health and function, a high rate of hypovitaminosis D among female patients with a variety of musculoskeletal issues could be of high clinical relevance.

HYPOTHESIS

There is a high prevalence of low vitamin D in female patients with both acute and overuse sports-related issues of both soft tissue and bone.

STUDY DESIGN

Prospective cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Female patients, aged 16 to 40 years, presenting with lower extremity injury diagnosed within the past 4 weeks, no use of multivitamin or vitamin D supplement, and no history of malabsorption syndrome met the inclusion criteria. Vitamin D levels were assessed and categorized as normal (≥32 ng/mL) and low, which includes insufficient (20.01-31.9 ng/mL) and deficient (≤20 ng/mL).

RESULTS

Of the 105 patients enrolled, 65.7% had low vitamin D. Within the low vitamin D cohort, 40.6% were deficient and 59.4% were insufficient. Injuries were grouped into overuse or acute with 74 overuse injuries and 31 acute injuries, exhibiting low vitamin D prevalence of 60.8% and 77.4%, respectively. Patients with ligamentous/cartilaginous injuries exhibited the highest percentage of low vitamin D (76.5%), followed by those with patellofemoral-related complaints (71.0%), muscle/tendon injuries (54.6%), and bone stress injuries (45.5%). In univariable analysis, older age, non-White race, less physical activity, less high-intensity interval training days, less endurance training days, and more rest days showed an association with low vitamin D, but none showed an independent association in multivariable analysis.

CONCLUSION

The prevalence of low vitamin D in female patients with various musculoskeletal complaints was high. Clinicians should evaluate for low vitamin D in both acute and overuse injuries.

CLINICAL RELEVANCE

In addition to screening, this study suggests that clinicians should evaluate for low vitamin D levels beyond bone stress injuries in the setting of acute and overuse injuries.

Epidemiology of the association between serum 25-hydroxyvitamin D levels and musculoskeletal conditions among elderly individuals: a literature review

Background

Vitamin D deficiency is associated with osteoporosis, fracture, muscle weakness, falls, and osteoarthritis in adults. Elderly individuals are more likely to present with poor musculoskeletal conditions. Recently, several epidemiological studies have assessed the correlation between serum 25-hydroxyvitamin D (25(OH)D) levels and musculoskeletal conditions in elderly individuals.

Main text

Osteoporosis is a skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. Numerous studies have shown a positive association between serum 25(OH)D levels and bone mineral density. Only a few studies have reported an association between serum 25(OH)D levels and quantitative ultrasound (QUS) parameters. Low serum 25(OH)D level may be a risk factor for hip fracture. However, data on the association between vitamin D deficiency and the incidence of non-hip fracture are contrasting. Falls are a major cause of mortality and morbidity in older adults. Several prospective population-based cohort studies have shown that low 25(OH)D levels are associated with an increased risk of falls. Reduced muscle strength and physical performance are risk factors for adverse events, including disability, institutionalization, and mortality. The role of vitamin D in musculoskeletal functionality (muscle weakness and physical performance) among elderly individuals is still controversial. Osteoarthritis (OA) is the most common form of arthritis and is a leading cause of disability among older adults. Data on the association between serum 25(OH)D levels and OA are contrasting.

Conclusion

Some studies have shown that vitamin D deficiency may be a risk factor for poor musculoskeletal conditions, such as osteoporosis, fracture, muscle weakness, falls, and osteoarthritis in adults. However, other studies did not find an association between serum 25(OH)D levels and musculoskeletal conditions.

Assessment of eldecalcitol and alendronate effect on postural balance control in aged women with osteoporosis

INTRODUCTION

Older people aged over 75 are more prone to falls because physical functions become deteriorated along with aging, and also fracture risk is strongly correlated with age. We evaluated the effects of anti-osteoporosis agents, eldecalcitol (ELD) and alendronate (ALN) on physical functions by assessing dynamic and static postural balance in aged patients with osteoporosis.

MATERIALS AND METHODS

A randomized, open-label, controlled clinical trial has been conducted with 124 female patients aged 65 or over with osteoporosis. Patients were randomly assigned to receive either 0.75 μg of ELD once-a-day or 35 mg of ALN once-a-week for 24 weeks. The primary endpoint was the change in a postural balance index, adjusted composite equilibrium score (CES) of sensory organization test (SOT). The SOT equilibrium scores, leg muscle strength, and other physical functions were also evaluated.

RESULTS

The Adjusted CES increased from baseline by 6.10% in the ELD group and 6.28% in the ALN group. There was no statistically significant difference between the two groups. The static postural balance at fixed platform were maintained in the ELD group, but declined in the ALN group. The dynamic postural balance at swaying platform and knee extension power increased from baseline in both groups.

CONCLUSIONS

These results suggest that ELD and ALN treatments may each be beneficial to improve postural balance control in older patients with osteoporosis via different mechanisms of action.

Relationship between serum vitamin D level and sarcopenia in chronic liver disease

AIM

Although the association of vitamin D with primary sarcopenia has been extensively investigated, its relationship with secondary sarcopenia in patients with liver disease remains unclear. This study aimed to identify factors associated with sarcopenia in patients with chronic liver disease with a focus on serum vitamin D levels.

METHODS

The study included 204 patients with chronic liver disease. Independent factors significantly associated with sarcopenia were determined using multiple logistic regression analysis. The sarcopenia diagnosis was based on the sarcopenia criteria proposed by the Japan Society of Hepatology. Serum 25-hydroxyvitamin D₃ (25[OH]D₃ ) levels to represent serum vitamin D levels were measured using double-antibody radioimmunoassay, and vitamin D deficiency was defined as a serum 25(OH)D₃ level of ≤20 ng/mL.

RESULTS

The prevalence of sarcopenia in the cirrhotic patients (28/76, 36.8%) was significantly higher than that in the non-cirrhotic patients (18/128, 14.1%; P = 2.48 × 10^-4 ). Sarcopenia was diagnosed in 44 (27.5%) of the 160 patients with vitamin D deficiency, and two (4.5%) of the 44 patients without vitamin D deficiency (P = 4.90 × 10^-3 ). On multivariate analysis, advanced age (odds ratio 1.11; P = 2.10 × 10^-4 ), low body mass index (odds ratio 1.42; p = 2.08 × 10^-5 ), and low serum 25(OH)D₃ level (odds ratio 1.13; p = 1.20 × 10^-2 ) were significant, independent factors associated with sarcopenia. Serum 25(OH)D₃ was positively correlated with grip strength and skeletal muscle mass index.

CONCLUSION

Sarcopenia complicated by chronic liver disease was associated with advanced age, low body mass index, and low serum 25(OH)D₃ level.

Low serum 25-hydroxyvitamin D is associated with low grip strength in an older Japanese population

Positive associations between vitamin D levels and hand grip strength have been reported worldwide, but the results are not consistent and few studies on East Asian populations have been published. The aim of this study was to determine whether such an association is present in a community-dwelling Japanese population, including elderly and middle-aged individuals. This study used a cross-sectional design. Participants were 492 community-dwelling individuals aged ≥ 40 years living in Yuzawa Town, Japan. The health check examination was conducted in 2015, and serum 25-hydroxyvitamin D [25(OH)D, an index of vitamin D levels], and hand grip strength were measured. Covariates were serum albumin concentration, body mass index, and physical activity level. The associations of serum 25(OH)D concentrations with hand grip strength and low grip strength (< 26 kg for men and < 18 kg for women) were analyzed using analysis of covariance and multiple logistic regression. Mean (standard deviation) age and serum 25(OH)D were 75.4 (9.0) years and 30.9 (9.1) ng/mL, respectively. The prevalence of serum 25(OH)D < 20, 20-29, and ≥ 30 ng/mL was 7.3%, 37.8%, and 54.9%, respectively. Mean hand grip strength in the 25(OH)D < 20 ng/mL group was significantly lower than that in the ≥ 30 ng/mL group (adjusted P ≤ 0.001). The 25(OH)D < 20 ng/mL group was significantly more likely to have low grip strength than the 25(OH)D ≥ 30 ng/mL group (odds ratio = 4.12). In conclusion, low serum 25(OH)D concentration (< 20 ng/mL) is associated with low grip strength in an older Japanese population.

Effect of increased serum 25(OH)D and calcium on structure and function of post-menopausal women: a pilot study

The purpose was to determine if increasing serum 25(OH)D and calcium in postmenopausal women increased skeletal muscle size, strength, balance, and functional task performance while decreasing muscle fatigue. PCSA of the vastus lateralis increased and ascent of stairs time decreased after 6 months of increased serum 25(OH)D.

PURPOSE

The Institute of Medicine recommends ≥ 20 ng/ml of serum 25-hydroxyvitamin D [25(OH)D] for bone and overall health. Serum 25(OH)D levels have been associated with physical performance, postural sway, and falls. The purpose of this study was to determine if increasing postmenopausal women's serum 25(OH)D levels from 20-30 ng/ml to 40-50 ng/ml improved skeletal muscle size, strength, balance, and functional performance while decreasing skeletal muscle fatigue.

METHODS

Twenty-six post-menopausal women (60-85 years old) with baseline serum 25(OH)D levels between 20 and 30 ng/ml were recruited. Oral over-the-counter (OTC) vitamin D3 and calcium citrate were prescribed to increase subjects' serum 25(OH)D to levels between 40 and 50 ng/ml, serum calcium levels above 9.2 mg/dl, and PTH levels below 60 pg/ml, which were confirmed at 6 and 12 weeks. Outcome measures assessed at baseline and 6 months included muscle physiological cross-sectional area (PCSA), muscle strength, postural balance, time to perform functional tasks, and muscle fatigue. Repeated measures comparisons between baseline and follow-up were performed.

RESULTS

Nineteen subjects completed the study. One individual could not afford the time commitment for the repeated measures. Three individuals did not take their vitamin D as recommended. Two subjects were lost to follow-up (lack of interest), and one did not achieve targeted serum 25(OH)D. Vastus lateralis PCSA increased (p = 0.007) and ascent of stair time decreased (p = 0.042) after 6 months of increasing serum 25(OH)D levels from 20-30 ng/ml to 40-50 ng/ml. Isometric strength was unchanged. Anterior-posterior center of pressure (COP) excursion and COP path length decreased (p < 0.1) albeit non-significantly, suggesting balance may improve from increased serum 25(OH)D and calcium citrate levels.

CONCLUSIONS

Several measures of muscle structure and function were sensitive to elevated serum 25(OH)D and calcium levels indicating that further investigation of this phenomenon in post-menopausal women is warranted.

Opposing effects of 25-hydroxy- and 1α,25-dihydroxy-vitamin D3 on pro-cachectic cytokine-and cancer conditioned medium-induced atrophy in C2C12 myotubes

AIM

Loss of skeletal muscle is one of the main features of cancer cachexia. Vitamin D (VD) deficiency is associated with impairment of muscle mass and performance and is highly prevalent in cachectic patients; therefore, VD supplementation has been proposed to counteract cancer cachexia-associated muscle loss. However, in both cachectic cancer patients and tumour-bearing animals, VD supplementation led to disappointing results, urging the need for a better understanding of VD activity on skeletal muscle.

METHODS

Cancer-associated muscle wasting was reproduced in vitro by treating C2C12 myotubes with cancer cell conditioned medium, a combination of TNF-α and IFNγ or IL-6 pro-cachectic cytokines. The biological effects and mechanisms of action of 1,25-dihydroxy VD (1,25 VD) and its precursor 25-hydroxy VD (25 VD) on myotubes were explored.

RESULTS

We demonstrated that only 25 VD was able to protect from atrophy by activating Akt signalling, inducing protein synthesis, and stimulating the autophagic flux, while 1,25 VD had an atrophic activity per se, increasing FoxO3 levels, inducing the expression of atrogenes, and blocking the autophagic flux. Furthermore, we showed that the contrasting activities of these VD metabolites on C2C12 myotubes depend on a differential induction of VD-24-hydroxylase and transformation of VD metabolites in pro-atrophic 24-hydroxylated products, as silencing of VD-24-hydroxylase reduced the atrophic activity of 1,25 VD.

CONCLUSIONS

Altogether these data might explain the lack of efficacy of VD treatment in vivo for the protection of muscle mass in cancer.

Association between vitamin D deficiency and allergic symptom in pregnant women

BACKGROUND

Vitamin D has been reported to affect both innate, and acquired immunity with immune cells such as dendritic cells having the vitamin D receptors. The co-occurrence of the high prevalence of allergic diseases and vitamin D deficiency globally documented in recent decades, has prompted a hypothesis on whether there is a reasonable association between them.

OBJECTIVE

To investigate the association between serum vitamin D deficiency and allergic symptoms.

METHODS

Historical cohort. On a cohort study for the association between desert dust exposure and allergic symptoms in 3,327 pregnant women during spring and fall in 2011-2013 in Japan conducted as an adjunct study to the Japan Environment and Children's Study, we promptly acquired subjects' daily allergic symptom scores by sending a web-based questionnaire to each participant on some days. Of the 29,434 answers provided by 3,327 participating pregnant women, we extracted 13,356 answers from 1,475 pregnant women that were answered within a 3-month period after blood samplings. And we measured 25(OH)D levels on those samples to investigate the association between their vitamin D deficiency (serum 25(OH)D < 20ng/mL) and the occurrence of any allergic symptom (allergic symptom score> 0) within 3 months.

RESULTS

Serum 25(OH)D was less than 20ng/mL in 1,233 of 1,745 samples (70.7%). The adjusted odds ratio (aOR) for occurrence of any allergic symptom in deficient cases compared with non-deficient cases was 1.33 (95% CI: 1.07-1.64, p = 0.01). Further, vitamin D deficiency significantly enhanced the risk increase at desert dust events and at pollen exposure (p-values for interaction <0.1).

CONCLUSION

We confirmed the association between serum vitamin D deficiency and allergic symptoms in Japanese pregnant women.

Mechanisms of vitamin D on skeletal muscle function: oxidative stress, energy metabolism and anabolic state

PURPOSE

This review provides a current perspective on the mechanism of vitamin D on skeletal muscle function with the emphasis on oxidative stress, muscle anabolic state and muscle energy metabolism. It focuses on several aspects related to cellular and molecular physiology such as VDR as the trigger point of vitamin D action, oxidative stress as a consequence of vitamin D deficiency.

METHOD

The interaction between vitamin D deficiency and mitochondrial function as well as skeletal muscle atrophy signalling pathways have been studied and clarified in the last years. To the best of our knowledge, we summarize key knowledge and knowledge gaps regarding the mechanism(s) of action of vitamin D in skeletal muscle.

RESULT

Vitamin D deficiency is associated with oxidative stress in skeletal muscle that influences the mitochondrial function and affects the development of skeletal muscle atrophy. Namely, vitamin D deficiency decreases oxygen consumption rate and induces disruption of mitochondrial function. These deleterious consequences on muscle may be associated through the vitamin D receptor (VDR) action. Moreover, vitamin D deficiency may contribute to the development of muscle atrophy. The possible signalling pathway triggering the expression of Atrogin-1 involves Src-ERK1/2-Akt- FOXO causing protein degradation.

CONCLUSION

Based on the current knowledge we propose that vitamin D deficiency results from the loss of VDR function and it could be partly responsible for the development of neurodegenerative diseases in human beings.

Low serum 25-hydroxyvitamin D increases cognitive impairment in elderly people

It has been reported that many elderly people have low serum levels of 25-hydroxyvitamin D [25(OH)D] and that serum 25(OH)D levels may have a relationship with cognitive function. The aim of this study was to examine the relationship between serum 25(OH)D levels and cognitive function in a Japanese population. This cross-sectional study was performed as a part of the Project in Sado for Total Health (PROST). The PROST study evaluated cognitive state and serum vitamin D level from June 2011 to November 2013 for 740 patients (431 men and 309 women). The Mini-Mental State Examination-Japanese version (MMSE-J) and serum 25(OH)D level measurements were used as assessment tools. Cognitive impairment was defined using MMSE-J ≤ 23 as a cutoff. Multiple logistic regression analyses were performed to calculate the odds ratios (ORs) for low MMSE-J scores. The average subject age was 68.1 years, the average MMSE- J score was 25.9, and the average 25(OH)D level was 24.6 ng/mL. Significant ORs for cognitive impairment were observed for both high age and low serum 25(OH)D. The adjusted OR for the lowest versus highest serum 25(OH)D quartiles was 2.70 (95% confidence interval 1.38-5.28, P = 0.0110). Low serum 25(OH)D levels were independently associated with a higher prevalence of cognitive impairment.

Vitamin D status and functional parameters: A cross-sectional study in an older population

The present study aims to clarify the association of vitamin D status with functionality, measured through gait speed and hand grip strength, in a sample of older adults, considering sex-specific characteristics and the potential confounding effect of lifestyle factors, disease, skin phenotype, season of blood collection and vitamin D supplementation. The Nutrition UP 65 cross-sectional study was conducted in a population-based sample of 1,425 older adults ≥ 65 years old. Serum levels of 25-hydroxyvitamin D were quantified through electrochemiluminescence immunoassay. Multinomial logistic regressions were carried out using quartiles of gait speed and of hand grip strength as dependent variables. Participants at risk of vitamin D inadequacy (30.0-49.9 nmol/L) and deficiency (< 30.0 nmol/L) presented higher adjusted odds ratio of the lowest values of gait speed and hand grip strength than those with adequate vitamin D levels (≥ 50.0 nmol/L). These associations were strongest among men at risk of vitamin D deficiency [adjusted odds ratio for the lowest quartile of gait speed = 3.24; 95% CI: 1.56–6.73 and for the lowest quartile of hand grip strength = 3.28; 95% CI: 1.47-7.31] than in women at risk of vitamin D deficiency [adjusted odds ratio for the lowest quartile of gait speed = 2.72; 95% CI: 1.37-5.41 and for the lowest quartile of hand grip strength = 1.56; 95% CI: 0.81–3.00]. In conclusion, in older adults, particularly in men, the risk of vitamin D deficiency was directly associated with the lowest values of gait speed and of hand grip strength. However, randomized controlled trials are needed to overcome the possibility of reverse causation and residual confounding. Present results emphasise the need for strategies to promote the reduction of the high prevalence of low vitamin D status among the Portuguese older adult population.

Determinants of muscle preservation in individuals with cerebral palsy across the lifespan: a narrative review of the literature

In individuals with cerebral palsy (CP), smaller muscle and atrophy are present at young age. Many people with CP also experience a decline in gross motor function as they age, which might be explained by the loss of muscle mass. The clinical observation of muscle wasting has prompted a comparison with sarcopenia in older adults, and the term accelerated musculoskeletal ageing is often used to describe the hallmark phenotype of CP through the lifespan. However, there has been very little research emphasis on the natural history of ageing with CP and even less with respect to the determinants or prevention of muscle loss with CP. Considering the burgeoning interest in the science of muscle preservation, this paper aims to (i) describe the characteristics of accelerated musculoskeletal ageing in people with CP, (ii) describe the pathophysiology of sarcopenia and parallels with CP, and (iii) discuss possible therapeutic approaches, based on established approaches for sarcopenia.

Associations of vitamin D with insulin resistance, obesity, type 2 diabetes, and metabolic syndrome

The aim of this study is to determine the relationships of vitamin D with diabetes, insulin resistance obesity, and metabolic syndrome. Intra cellular vitamin D receptors and the 1-α hydroxylase enzyme are distributed ubiquitously in all tissues suggesting a multitude of functions of vitamin D. It plays an indirect but an important role in carbohydrate and lipid metabolism as reflected by its association with type 2 diabetes (T2D), metabolic syndrome, insulin secretion, insulin resistance, polycystic ovarian syndrome, and obesity. Peer-reviewed papers, related to the topic were extracted using key words, from PubMed, Medline, and other research databases. Correlations of vitamin D with diabetes, insulin resistance and metabolic syndrome were examined for this evidence-based review. In addition to the well-studied musculoskeletal effects, vitamin D decreases the insulin resistance, severity of T2D, prediabetes, metabolic syndrome, inflammation, and autoimmunity. Vitamin D exerts autocrine and paracrine effects such as direct intra-cellular effects via its receptors and the local production of 1,25(OH)₂D₃, especially in muscle and pancreatic β-cells. It also regulates calcium homeostasis and calcium flux through cell membranes, and activation of a cascade of key enzymes and cofactors associated with metabolic pathways. Cross-sectional, observational, and ecological studies reported inverse correlations between vitamin D status with hyperglycemia and glycemic control in patients with T2D, decrease the rate of conversion of prediabetes to diabetes, and obesity. However, no firm conclusions can be drawn from current studies, because (A) studies were underpowered; (B) few were designed for glycemic outcomes, (C) the minimum (or median) serum 25(OH) D levels achieved are not measured or reported; (D) most did not report the use of diabetes medications; (E) some trials used too little (F) others used too large, unphysiological and infrequent doses of vitamin D; and (G) relative paucity of rigorous clinical data on the effects of vitamin D sufficiency on non-calcium endpoints. Although a large number of observational studies support improving T2D, insulin resistance, obesity, and metabolic syndrome with vitamin D adequacy, there is a lack of conclusive evidence from randomized control clinical trials that, these disorders are prevented following optimization of serum levels of 25(OH)D. However, none of the currently conducted clinical studies would resolve these issues. Thus, specifically designed, new clinical studies are needed to be conducted in well-defined populations, following normalizing the serum vitamin D levels in vitamin D deficient prediabetes subjects, to test the hypothesis that hypovitaminosis D worsens these disorders and correction would alleviate it.

Non-musculoskeletal benefits of vitamin D

The aim of this study is to determine and critically evaluate the plausible relationships of vitamin D with extra-skeletal tissues in humans. Severe vitamin D deficiency results in rickets in children and osteomalacia in adults; these beneficial effects in the musculoskeletal system and certain physiological functions are well understood. Nevertheless, mounting reports support additional beneficial effects of vitamin D, outside the musculoskeletal system. This review explores the recent advances in knowledge about the non-skeletal effects of vitamin D. Peer-reviewed papers were extracted from research databases using key words, to assess correlations between vitamin D and extra-skeletal diseases and conditions. As per the guidelines of the Preferred Reporting Items for Systematic Reviews (PRISMA); general interpretations of results are included; taking into consideration the broader evidence and implications. This review summarizes current knowledge of the effects of vitamin D status on extra-skeletal tissues with special attention given to relationships between vitamin D status and various diseases commonly affecting adults; the effects of intervention with vitamin D and exposure to sunlight. Evidence suggests that vitamin D facilitates the regulation of blood pressure; and cardiac; endothelial; and smooth muscle cell functions; playing an important role in cardiovascular protection. In addition; 1,25(OH)₂D improves immunity; subdues inflammation; and reduces the incidence and severity of common cancers; autoimmune diseases and infectious diseases. Almost all adequately powered; epidemiological and biological studies that use; adequate doses of vitamin D supplementation in D-deficient populations have reported favorable outcomes. These studies have concluded that optimizing 25(OH)D status improves the functionality of bodily systems; reduces comorbidities; improves the quality of life; and increases survival. Although accumulating evidence supports biological associations of vitamin D sufficiency with improved physical and mental functions; no definitive evidence exists from well-designed; statistically powered; randomized controlled clinical trials. Nevertheless, most studies point to significant protective effects of vitamin D in humans when the minimum 25(OH)D serum level exceeds 30ng/mL and is maintained throughout the year.

Assessment criteria for vitamin D deficiency/insufficiency in Japan - proposal by an expert panel supported by Research Program of Intractable Diseases, Ministry of Health, Labour and Welfare, Japan, The Japanese Society for Bone and Mineral Research and The Japan Endocrine Society [Opinion]

Vitamin D is indispensable for the maintenance of bone and mineral health. Inadequate vitamin D action increases the risk for various musculoskeletal/mineral events including fracture, fall, secondary hyperparathyroidism, diminished response to antiresorptives, rickets/osteomalacia, and hypocalcemia. Its most common cause in recent years is vitamin D deficiency/insufficiency, clinically defined by low serum 25-hydroxyvitamin D [25(OH)D] level. Guidelines for vitamin D insufficiency/deficiency defined by serum 25(OH)D concentrations have been published all over the world. In Japan, however, the information on the associations between serum 25(OH)D and bone and mineral disorders has not been widely shared among healthcare providers, partly because its measurement had not been reimbursed with national medical insurance policy until August 2016. We have set out to collect and analyze Japanese data on the relationship between serum 25(OH)D concentration and bone and mineral events. Integrating these domestic data and published guidelines worldwide, here we present the following assessment criteria for vitamin D sufficiency/insufficiency/deficiency using serum 25(OH)D level in Japan. 1) Serum 25(OH)D level equal to or above 30 ng/mL is considered to be vitamin D sufficient. 2) Serum 25(OH)D level less than 30 ng/mL but not less than 20 ng/mL is considered to be vitamin D insufficient. 3) Serum 25(OH)D level less than 20 ng/mL is considered to be vitamin D deficient. We believe that these criteria will be clinically helpful in the assessment of serum 25(OH)D concentrations and further expect that they will form a basis for the future development of guidelines for the management of vitamin D deficiency/insufficiency.

Assessment criteria for vitamin D deficiency/insufficiency in Japan: proposal by an expert panel supported by the Research Program of Intractable Diseases, Ministry of Health, Labour and Welfare, Japan, the Japanese Society for Bone and Mineral Research and the Japan Endocrine Society [Opinion]

Vitamin D is indispensable for the maintenance of bone and mineral health. Inadequate vitamin D action increases the risk for various musculoskeletal/mineral events including fracture, fall, secondary hyperparathyroidism, diminished response to antiresorptives, rickets/osteomalacia, and hypocalcemia. Its most common cause in recent years is vitamin D deficiency/insufficiency, clinically defined by a low serum 25-hydroxyvitamin D [25(OH)D] level. Guidelines for vitamin D insufficiency/deficiency defined by serum 25(OH)D concentrations have been published all over the world. In Japan, however, the information on the associations between serum 25(OH)D and bone and mineral disorders has not been widely shared among healthcare providers, partly because its measurement had not been reimbursed with national medical insurance policy until August 2016. We have set out to collect and analyze Japanese data on the relationship between serum 25(OH)D concentration and bone and mineral events. Integrating these domestic data and published guidelines worldwide, here, we present the following assessment criteria for vitamin D sufficiency/insufficiency/deficiency using serum 25(OH)D level in Japan. (1) Serum 25(OH)D level equal to or above 30 ng/ml is considered to be vitamin D sufficient. (2) Serum 25(OH)D level less than 30 ng/ml but not less than 20 ng/ml is considered to be vitamin D insufficient. (3) Serum 25(OH)D level less than 20 ng/ml is considered to be vitamin D deficient. We believe that these criteria will be clinically helpful in the assessment of serum 25(OH)D concentrations and further expect that they will form a basis for the future development of guidelines for the management of vitamin D deficiency/insufficiency.

Vitamin D and the Mechanisms, Circumstances and Consequences of Falls in Older Adults: A Case-Control Study

OBJECTIVES

To determine i) whether cases of elderly fallers had lower serum 25-hydroxyvitamin D (25OHD) concentration than controls without history of falls; and ii) whether serum 25OHD concentration was associated with specific mechanisms, circumstances and consequences of falls.

DESIGN

Case-control study with a 1:2 ratio.

SETTING

Geriatric ward of the University Hospital of Angers, France, between February 2012 and March 2014.

PARTICIPANTS

216 inpatients (72 cases and 144 age- and gender-matched controls).

MEASUREMENT

Falls were defined as involuntary events causing the person to the ground or other lower level. The main mechanisms, circumstances and consequences of falls were identified using standardized questionnaires. Vitamin D deficiency was defined as serum 25OHD concentration ≤25nmol/L. Age, gender, body mass index, polypharmacy, use antihypertensive drugs, use psychoactive drugs, disability, cognitive performance, serum concentrations of parathyroid hormone, creatinine and albumin, and season of evaluation were used as potential confounders.

RESULTS

216 participants (72 cases and 144 controls) were included in the study. There was no between-group difference in the prevalence of vitamin D deficiency (P=0.176). After adjusting for confounding factors, vitamin D deficiency was positively associated with falls (OR=4.03, P=0.014). Finally, the fallers with vitamin D deficiency exhibited more often orthostatic hypotension (68.8% against 33.3%, P=0.039) and a history of recurrent falls (85% against 50%, P=0.002) than those without vitamin D deficiency.

CONCLUSION

This case-control study reported that vitamin D deficiency was associated with falls in older inpatients. There was a greater prevalence of orthostatic hypotension and of the reccurrence of falls among fallers with vitamin D deficiency, suggesting that vitamin D may influence the conditions predisposing to falls rather than the fall by itself.

Factors related to curved femur in elderly Japanese women

BACKGROUND

Multiple factors are involved in the development of atypical femoral fractures, and excessive curvature of the femur is thought to be one of them. However, the pathogenesis of femoral curvature is unknown. We evaluated the influence of factors related to bone metabolism and posture on the development of femoral curvature.

METHODS

A total of 139 women participated in the present study. Curvatures were measured using antero-posterior and lateral radiography of the femur. We evaluated some bone and vitamin D metabolism markers in serum, the bone mineral density (BMD), lumbar spine alignment, and pelvic tilt.

RESULTS

We divided the women into two groups, curved and non-curved groups, based on the average plus standard deviation as the cut-off between the groups. When univariate logistic regression analysis was performed to detect factors affecting femoral curvature, the following were identified as indices significantly affecting the curvature: age of the patients, serum concentrations of calcium, intact parathyroid hormone, pentosidine, homocysteine and 25-hydroxyvitamin D (25(OH)D), and BMD of the proximal femur (P < 0.05) both in the lateral and anterior curvatures. When we used multivariate analyses to assess these factors, only 25(OH)D and age (lateral and anterior standardized odds ratio: 0.776 and 0.385, and 2.312 and 4.472, respectively) affected the femoral curvature (P < 0.05).

CONCLUSION

Femoral curvature is strongly influenced by age and serum vitamin D.

Japanese elderly persons walk faster than non-Asian elderly persons: a meta-regression analysis

[Purpose] The purpose of this study was to clarify ethnic differences in walking speed by comparing walking speed in both Japanese and non-Asian elderly individuals and to investigate the necessity of consideration of ethnic differences in walking speed. [Subjects and Methods] Articles that reported comfortable walking speeds for community-dwelling elderly individuals were identified from electronic databases. Articles that involved community-dwelling individuals who were 60 years old or older and well functioning were included in the study. Articles that involved Asians were excluded. Weighted means for 5-m walking times were calculated as walking speeds from the Japanese and non-Asian sample data. The effects of age, gender, and ethnicity on 5-m walking times were then investigated using meta-regression analysis. [Results] Twenty studies (34 groups) were included for Japanese, and 16 studies (28 groups) were included for non-Asians. The weighted mean 5-m walking time was estimated to be 4.15 sec (95% confidence interval [CI]: 3.87-4.44) for Japanese and 4.24 sec (95% CI: 4.09-4.40) for non-Asians. Furthermore, using meta-regression analysis adjusted for age and gender, the 5-m walking time was 0.40 sec faster (95% CI: 0.03-0.77) for Japanese than for non-Asian elderly individuals. [Conclusion] Walking speed appeared faster for Japanese community-dwelling elderly individuals than for non-Asian elderly individuals.

Reference values for hand grip strength in Japanese community-dwelling elderly: a meta-analysis

OBJECTIVES

Reference values for hand grip strength in Japanese community-dwelling elderly independent in activities of daily living (ADLs) were calculated by meta-analysis.

METHODS

Papers reporting data on hand grip strength in elderly Japanese adults ≥60 years of age and independent in ADLs were retrieved from electronic databases. Data were extracted from the selected papers and the weighted mean for hand grip strength by sex was calculated by random effect model. The association of hand grip strength with age and body weight was also analyzed using meta-regression analysis.

RESULTS

Data for 15,784 individuals (5216 men and 10,568 women; mean age 67.0-79.8 years) were extracted from 97 sets of data from 33 papers. The weighted mean for hand grip strength was calculated as 33.11 kg [95 % CI 32.27-33.96] in men and 20.92 kg [95 % CI 20.45-21.39] in women. A significant negative correlation was also seen between hand grip strength and age.

CONCLUSIONS

The mean hand grip strength of elderly people calculated in this study can be used as a reference value for the hand grip strength of Japanese community-dwelling elderly who are independent in ADLs. However, age needs to be considered in reference values for hand grip strength.

Glucosamine-containing supplement improves locomotor functions in subjects with knee pain: a randomized, double-blind, placebo-controlled study

BACKGROUND

The aim of this study was to investigate the ability of a glucosamine-containing supplement to improve locomotor functions in subjects with knee pain.

METHODS

A randomized, double-blind, placebo-controlled, parallel-group comparative study was conducted for 16 weeks in 100 Japanese subjects (age, 51.8±0.8 years) with knee pain. Subjects were randomly assigned to one of the two supplements containing 1) 1,200 mg of glucosamine hydrochloride, 60 mg of chondroitin sulfate, 45 mg of type II collagen peptides, 90 mg of quercetin glycosides, 10 mg of imidazole peptides, and 5 μg of vitamin D per day (GCQID group, n=50) or 2) a placebo (placebo group, n=50). Japanese Knee Osteoarthritis Measure, visual analog scale score, normal walking speed, and knee-extensor strength were measured to evaluate the effects of the supplement on knee-joint functions and locomotor functions.

RESULTS

In subjects eligible for efficacy assessment, there was no significant group × time interaction, and there were improvements in knee-joint functions and locomotor functions in both groups, but there was no significant difference between the groups. In subjects with mild-to-severe knee pain at baseline, knee-extensor strength at week 8 (104.6±5.0% body weight vs 92.3±5.5% body weight, P=0.030) and the change in normal walking speed at week 16 (0.11±0.03 m/s vs 0.05±0.02 m/s, P=0.038) were significantly greater in the GCQID group than in the placebo group. Further subgroup analysis based on Kellgren-Lawrence (K-L) grade showed that normal walking speed at week 16 (1.36±0.05 m/s vs 1.21±0.02 m/s, P<0.05) was significantly greater in the GCQID group than in the placebo group in subjects with K-L grade I. No adverse effect of treatment was identified in the safety assessment.

CONCLUSION

In subjects with knee pain, GCQID supplementation was effective for relieving knee pain and improving locomotor functions.

Physical performance and life quality in postmenopausal women supplemented with vitamin D: a two-year prospective study

AIM

To investigate the effects of calcium and vitamin D supplementation on bone turnover marker levels, muscle strength and quality of life in postmenopausal Chinese women.

METHODS

A total of 485 healthy postmenopausal Chinese women (63.44±5.04 years) were enrolled in this open-label, 2-year, prospective, community-based trial. The participants were divided into group A, B, C, which were treated with calcium (600 mg/d) alone, calcium (600 mg/d) and cholecalciferol (800 IU/d) or calcium (600 mg/d) and calcitriol (0.25 μg/d), respectively, for 2 years. Serum levels of 25-hydroxyvitamin D, parathyroid hormone, β-CTX and P1NP were measured, and the muscle strength and quality of life were assessed at baseline and at 12- and 24-month follow-ups.

RESULTS

Four hundred and sixty one participants completed this study. Serum levels of 25-hydroxyvitamin D were significantly increased in group C, but not changed in groups A and B at 24-month follow-up. Serum levels of parathyroid hormone, bone turnover marker β-CTX and bone formation marker P1NP were significantly decreased in group C, while serum levels of β-CTX were increased in group A at 24-month follow-up. The participants in group C maintained the grip strength, while those in groups A and B exhibited decreased grip strength at 24-month follow-up. The quality of life for the participants in groups B and C remained consistent, but that in group A was deteriorated at 24-month follow-up.

CONCLUSION

Supplementation with calcitriol and calcium modifies the bone turnover marker levels, and maintains muscle strength and quality of life in postmenopausal Chinese women, whereas supplementation with cholecalciferol and calcium prevents aging-mediated deterioration in quality of life.

Serum 25-hydroxyvitamin D level and risk of falls in Japanese community-dwelling elderly women: a 1-year follow-up study

The present prospective follow-up study among 1,393 community-dwelling elderly women aged 75 years or older was conducted to clarify the association between serum 25-hydroxyvitamin D (25(OH)D) level and risk of falls. Lower serum 25(OH)D, particularly level <20 ng/mL, was significantly associated with an increased risk of falls.

INTRODUCTION

Serum 25(OH)D level has been revealed to be important factor not only for skeletal health but also for fall prevention among the elderly. Our previous cross-sectional study indicated that low serum 25(OH)D level is associated with inferior physical performance and falls among elderly Japanese women. The present prospective study was designed to clarify the association between serum 25(OH)D level and risk of falls before and after 1 year of follow-up.

METHODS

The community-dwelling elderly women aged 75 years or older (N = 1,393) who participated in a mass health examination were followed 1 year later by a mailed self-administered questionnaire.

RESULTS

Responses were obtained from 1,285 subjects (response rate = 92.2%). The incidence of falls at baseline and at 1-year follow-up was 18.8 and 24.4%, respectively. The baseline prevalence of serum 25(OH)D <20 ng/mL was 35.2%. Odds ratios (95% confidence intervals) in the lowest tertile of serum 25(OH)D (<20 ng/mL) compared with those in the highest tertile (≥25 ng/mL) were 1.40 (1.01-1.94) for any falls and 1.47 (0.93-2.32) for recurrent falls vs. no falls adjusted for potential risk factors.

CONCLUSIONS

Among elderly Japanese women, the lower serum 25(OH)D, particularly level <20 ng/mL, was significantly associated with an increased risk of falls.

Determinants of serum 25-hydroxyvitamin D in Hong Kong

Vitamin D plays an important role in skeletal health throughout life. Some studies have hypothesised that vitamin D may reduce the risk of other diseases. Our study aimed to estimate age-specific and sex-specific serum 25-hydroxyvitamin D (25(OH)D) status and to identify the determinants of serum 25(OH)D status in Hong Kong, a subtropical city in southern China. In 2009–2010, households in Hong Kong were followed up to identify acute respiratory illnesses, and sera from 2694 subjects were collected in three to four different study phases to permit measurement of 25(OH)D levels at different times of the year. A questionnaire survey on diet and lifestyle was conducted among children, with simultaneous serum collection in April and May 2010. The mean of serum 25(OH)D levels in age groups ranged from 39 to 63 nmol/l throughout the year with the mean values in all age groups in spring below 50 nmol/l. Children aged 6–17 years, and girls and women had significantly lower serum 25(OH)D levels than adults, and boys and men, respectively (allP< 0·001). We estimated that serum 25(OH)D levels in Hong Kong followed a lagged pattern relative to climatic season by 5 weeks with lowest observed levels in early spring (March). For children aged 6–17 years, reporting a suntan, having at least 1 servings of fish/week and having at least 1 serving of eggs/week were independently associated with higher serum 25(OH)D levels. Adequate sunlight exposure and increased intake of dietary vitamin D could improve vitamin D status, especially for children and females in the winter and spring.

Persistent hypovitaminosis D and loss of hip bone mineral density over time as additional risk factors for recurrent falls in a population-based prospective cohort of elderly persons living in the community. The São Paulo Ageing & Health (SPAH) Study

We performed concomitant evaluation of clinical, laboratory, and bone mineral density (BMD) parameters as potential risk factors for falls in a population-based prospective cohort of older adults, since previous studies have focused mostly in clinical risk factors. Loss of hip BMD and persistent hypovitaminosis D were associated with recurrent falls in community-dwelling elderly.

INTRODUCTION

Few studies have performed a concomitant evaluation of clinical data, laboratory bone parameters, and bone mineral density (BMD) to determine more accurately the contribution of each of these variables to risk of falls in elderly persons. We investigated the association between bone parameters and recurrent falls in a population-based prospective cohort of community-dwelling older adults.

METHODS

A total of 705 elderly individuals (448 women, 257 men) were evaluated with clinical data, BMD, and laboratory bone tests at baseline and after a mean follow-up of 4.3 ± 0.8 years. Individuals with recurrent falls (≥2 falls in the previous year from the date of the second evaluation) were considered chronic fallers. Logistic regression models were used to identify independent risk factors for recurrent falls.

RESULTS

The frequency of chronic fallers was 16.5%. In multivariate analyses, risk factors for recurrent falls were visual impairment (odds ratio (OR) = 2.49, 95% confidence interval (CI) 1.30-4.74, p = 0.006), use of psychotropic drugs (OR = 2.47, 95% CI 1.37-4.49, p = 0.003), clinical fracture (OR = 2.78, 95% CI 1.48-5.20, p = 0.001), persistently low 25-hydroxyvitamin D (25OHD) (<20 ng/mL) (OR = 1.71, 95% CI 1.10-2.64, p = 0.016), and loss of total hip BMD during the study (OR = 1.21, 95% CI 1.17-1.25, p = 0.035 for each 4% decrease).

CONCLUSIONS

In addition to traditional clinical risk factors for falls, loss of hip BMD and hypovitaminosis D were associated with recurrent falls in community-dwelling elderly persons. Thus, recognizing these factors is essential to preventing falls and improving the outcomes of this population.

Vitamin D: a review on its effects on muscle strength, the risk of fall, and frailty

Vitamin D is the main hormone of bone metabolism. However, the ubiquitary nature of vitamin D receptor (VDR) suggests potential for widespread effects, which has led to new research exploring the effects of vitamin D on a variety of tissues, especially in the skeletal muscle. In vitro studies have shown that the active form of vitamin D, calcitriol, acts in myocytes through genomic effects involving VDR activation in the cell nucleus to drive cellular differentiation and proliferation. A putative transmembrane receptor may be responsible for nongenomic effects leading to rapid influx of calcium within muscle cells. Hypovitaminosis D is consistently associated with decrease in muscle function and performance and increase in disability. On the contrary, vitamin D supplementation has been shown to improve muscle strength and gait in different settings, especially in elderly patients. Despite some controversies in the interpretation of meta-analysis, a reduced risk of falls has been attributed to vitamin D supplementation due to direct effects on muscle cells. Finally, a low vitamin D status is consistently associated with the frail phenotype. This is why many authorities recommend vitamin D supplementation in the frail patient.

Effects of a combined physical training and nutrition intervention on physical performance and health-related quality of life in prefrail older women living in the community: a randomized controlled trial

OBJECTIVES

The purpose of this study was to examine whether a 12-week combined physical exercise training and nutritional intervention improves physical performance and enhances health-related quality of life (HRQOL) among prefrail elderly women living in the community.

DESIGN

This was a randomized controlled trial in which participants were recruited and randomly assigned to the exercise and nutrition group (EN, n = 30), exercise only group (E, n = 28), and control group (C, n = 31).

SETTING

Group training classes were held at a research center in Itabashi Ward, Tokyo, Japan.

PARTICIPANTS

Eighty-nine prefrail women aged 70 years or older.

INTERVENTION

The EN group participated in an exercise training and nutritional program (cooking class) once a week, and the E group participated in the exercise training program only.

MEASUREMENTS

Outcome measures that included physical performance (handgrip strength, balance, walking speed) and HRQOL (Medical Outcomes Study 36-Item Short Form Health Survey) were obtained at entry, the end of the 12-week intervention, and 6 months after completion of the intervention program.

RESULTS

At the end of the 12-week intervention, significant improvements in the physical component summary score and 3 (role physical, bodily pain, role emotional) of the 8 domains of the Medical Outcomes Study 36-Item Short Form Health Survey were observed in the EN group. The E group exhibited a significantly increased handgrip strength at postintervention. The positive effects, however, were not maintained at 6-month follow-up, but were reduced.

CONCLUSIONS

The combined physical exercise training and nutritional intervention program has beneficial effects on several domains of HRQOL and handgrip strength in prefrail elderly women living in the community. However, further studies are needed to examine approaches that facilitate maintenance of the improved outcomes by combined exercise training and nutritional intervention.

Questioning vitamin D status of elderly fallers and nonfallers: a meta-analysis to address a 'forgotten step'

BACKGROUND

Previous meta-analyses to determine the efficacy of vitamin D supplementation to prevent falls in the elderly have shown mixed results. Inconsistencies might depend on the dose of supplements, suggesting that serum 25-hydroxyvitamin D (25OHD) concentration could influence the risk of falling. Our objective was to systematically review and quantitatively analyse the relationship between serum 25OHD concentration and the occurrence of falls.

METHODS

A Medline search was conducted in December 2013, with no date limit, using the Medical Subject Heading terms 'Vitamin D' OR 'Ergocalciferols' OR 'Vitamin D deficiency' combined with 'Accidental Falls' OR 'Gait disorders, neurologic' OR 'Gait apraxia' OR 'Gait' OR 'Recurrent Falls' OR 'Falling'. Fixed and random-effects meta-analyses were performed to determine the following: (i) the effect size of the difference in 25OHD concentration between fallers and nonfallers and (ii) the risk of falling according to serum 25OHD concentration.

RESULTS

Of the 659 retrieved studies, 18 observational studies - including ten cross-sectional and eight cohort studies - met the selection criteria. All were of good quality. The number of participants ranged from 80 to 2957 (44-100% women); 11.0% to 69.3% were fallers. Serum 25OHD concentrations were 0.33 × SD lower in fallers compared to nonfallers [pooled effect size 0.33; 95% confidence interval (CI) 0.18-0.47]. The risk of falls was inversely associated with serum 25OHD concentration [summary odds ratio (OR) 0.97; 95% CI 0.96-0.99]. The association between falls and hypovitaminosis D varied according to the definition used; the summary OR for falls was 1.23 (95% CI 0.94-1.60) for 25OHD <10 ng mL(-1) , 1.44 (95% CI 1.17-1.76) for 25OHD <20 ng mL(-1) and 0.95 (95% CI 0.81-1.11) for 25OHD <30 ng mL(-1) .

CONCLUSIONS

Fallers have lower 25OHD concentrations, notably more often <20 ng mL(-1) , than nonfallers. These findings help to determine the profile of target populations that would most benefit from vitamin D supplements to prevent falls.