Is the 25-Hydroxy-Vitamin D Serum Concentration a Good Marker of Frailty?

Association between vitamin D3 levels and frailty in the elderly: A large sample cross-sectional study

Background

Frailty is recognized as a cornerstone of geriatric medicine. Accurately screening and identifying frailty can promote better quality and personalized medical services for the elderly. Previous studies have shown that the association between vitamin D and frailty in the elderly population is still controversial. More research is needed to explore the association between them.

Materials and methods

We used three waves of data from the National Health and Nutrition Examination Survey (NHANES). Based on the widely accepted AAH FRAIL Scale, we measured and evaluated the participants’ frailty from five aspects: fatigue, resistance, ambulation, illness, and loss of weight. All possible relevant variables are included. Machine learning XGboost algorithm, the Least Absolute Shrinkage Selection Operator (LASSO) regression and univariate logistic regression were used to screen variables, and multivariate logistic regression and generalized additive model (GAM) were used to build the model. Finally, subgroup analysis and interaction test were performed to further confirm the association.

Results

In our study, XGboost machine learning algorithm explored the relative importance of all included variables, which confirmed the close association between vitamin D and frailty. After adjusting for all significant covariates, the result indicated that for each additional unit of 25-hydroxyvitamin D3, the risk of frailty was reduced by 1.3% with a statisticaldifference. A smooth curve was constructed based on the GAM. It was found that there was a significant negative correlation between 25-hydroxyvitamin D3 and the risk of frailty.

Conclusion

There may be a negative correlation between 25-hydroxyvitamin D3 and the risk of frailty. However, more well-designed studies are needed to verify this relationship.

The role of vitamin D in the link between physical frailty and cognitive function: A mediation analysis in community-dwelling Chinese older adults

Background

Physical frailty and cognitive aging have important influences on poor clinical outcomes in older adults. Many studies have investigated the association between frailty and cognitive function, but whether vitamin D mediates the association between frailty and cognitive function is unclear. We explored the mediating role of vitamin D on the cross-sectional association between physical frailty and cognitive function using data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS).

Methods

We analyzed data from 1944 subjects aged 60 years and older from the 2011 CLHLS cohort. Frailty status was identified by the Osteoporotic Fracture Study (SOF) index. The Chinese version of the Mini-Mental State Examination (MMSE) was used to assess cognitive function. Linear regression models were used to examine the association between frailty, vitamin D, and cognition, adjusted for a range of covariates. Mediation analyses tested the indirect effects of vitamin D on physical frailty and cognitive function.

Result

Physical frailty was negatively associated with vitamin D levels and scores on the MMSE, and vitamin D levels were positively associated with scores on the MMSE. Linear regression analysis showed that physical frailty and serum vitamin D concentration were significant predictors of cognitive function. Importantly, mediation analysis showed that serum vitamin D concentration significantly mediated the relationship between physical frailty and cognitive function.

Conclusion

The association between physical frailty and cognitive function appears to be mediated by vitamin D. Future studies should explore whether serum vitamin D concentrations may mediate the association between physical frailty and cognitive decline and whether this mediating role is moderated by other factors.

Biomarkers shared by frailty and sarcopenia in older adults: A systematic review and meta-analysis

BACKGROUND

Physical frailty and sarcopenia show extensive clinical similarities. Whether biomarkers exist that are shared by the two conditions is presently unclear.

METHODS

We conducted a systematic review and meta-analysis of cross-sectional and longitudinal studies that investigated the association of frailty and/or sarcopenia with biomarkers as a primary or secondary outcome in adults aged 60 years and older. Only studies published in English that defined frailty using a validated scale and/or questionnaire and diagnosed sarcopenia according to the presence of muscle atrophy plus dynapenia or low physical function were included. Studies were identified from a systematic search of MEDLINE and SCOPUS databases from inception through August 2020. The quality of reporting of each study was assessed by using the Quality Assessment Tool for Observational Cohort, Cross-Sectional and Case-Control studies of the National Institute of Health. A meta-analysis was conducted when at least three studies investigated the same biomarker in both frailty and sarcopenia. Pooled effect size was calculated based on standard mean differences and random-effect models. Sensitivity analysis was performed based on age and the setting where the study was conducted.

RESULTS

Eighty studies (58 on frailty and 22 on sarcopenia) met the inclusion criteria and were included in the qualitative analysis. Studies on frailty included 33,160 community-dwellers, hospitalized, or institutionalized older adults (60-88 years) from 21 countries. Studies on sarcopenia involved 4904 community-living and institutionalized older adults (68-87.6 years) from 9 countries. Several metabolic, inflammatory, and hematologic markers were found to be shared between the two conditions. Albumin and hemoglobin were negatively associated with both frailty and sarcopenia. Interleukin 6 was associated with frailty and sarcopenia only in people aged < 75. Community-dwelling older adults with frailty and sarcopenia had higher levels of tumor necrosis factor alpha compared with their robust and non-sarcopenic counterparts.

CONCLUSIONS

A set of metabolic, hematologic, and inflammatory biomarkers was found to be shared by frailty and sarcopenia. These findings fill a knowledge gap in the quest of biomarkers for these conditions and provide a rationale for biomarker selection in studies on frailty and sarcopenia.

Pinpointing a Role for Vitamin D in Frailty: A Time for Animal Models?

Frailty is a condition marked by greater susceptibility to adverse outcomes, including disability and mortality, which affects up to 50% of those 80 years of age and older. Concurrently, serum vitamin D insufficiency and deficiency, for which as many as 70% of older adults may be at risk, potentially play an important role in frailty onset and progression. Large population driven studies have uncovered associations between low serum vitamin D levels and higher incidence of frailty. However, attempts to apply vitamin D therapeutically to treat and/or prevent frailty have not yielded consistent support for benefits. Given the complexity and inconsistency arising from human studies involving vitamin D, our research group has recently published on animal models of vitamin D insufficiency. Combining our model with the emerging development of animal frailty assessment, we identified that higher than standard levels of vitamin D supplementation may delay frailty in mice. In this viewpoint article, we will discuss current knowledge regarding the importance of vitamin D in frailty progression, the emerging significance of animal models in addressing these relationships, and the future for pre-clinical and clinical research.

Low Vitamin D Levels and Frailty Status in Older Adults: A Systematic Review and Meta-Analysis

Serum vitamin D deficiency is widespread among older adults and is a potential modifiable risk factor for frailty. Moreover, frailty has been suggested as an intermediate step in the association between low levels of vitamin D and mortality. Hence, we conducted a systematic review of the literature and meta-analysis to test the possible association of low concentrations of serum 25-hydroxyvitamin D (25(OH)D), a marker of vitamin D status, with frailty in later life. We reviewed cross-sectional or longitudinal studies evaluating populations of older adults and identifying frailty by a currently validated scale. Meta-analyses were restricted to cross-sectional data from studies using Fried’s phenotype to identify frailty. Twenty-six studies were considered in the qualitative synthesis, and thirteen studies were included in the meta-analyses. Quantitative analyses showed significant differences in the comparisons of frail (standardized mean difference (SMD)—1.31, 95% confidence interval (CI) (−2.47, −0.15), p = 0.0271) and pre-frail (SMD—0.79, 95% CI (−1.58, −0.003), p = 0.0491) subjects vs. non-frail subjects. Sensitivity analyses reduced heterogeneity, resulting in a smaller but still highly significant between-groups difference. Results obtained indicate that lower 25(OH)D levels are significantly associated with increasing frailty severity. Future challenges include interventional studies testing the possible benefits of vitamin D supplementation in older adults to prevent/palliate frailty and its associated outcomes.

Circulating biomarkers characterizing physical frailty: CRP, hemoglobin, albumin, 25OHD and free testosterone as best biomarkers. Results of a meta-analysis

INTRODUCTION

During aging, individuals can be classified as being in one of 3 different states: robust, frail or dependent. Frailty is described as reversible, so early detection offers the potential of returning the subject to a robust status. There are multiple clinical frailty scales but no gold standard and frailty is not systematically assessed in clinicians' daily practice. Reliable biomarkers of frailty are lacking, however, while their identification and systematic use would make this simple scale a useful clinical tool.

OBJECTIVE

To conduct a review of the literature concerning the biomarkers associated with frailty and to compare in a meta-analysis the plasmatic values of each biomarker in the frail with the robust group.

RESULTS

503 articles were identified on PubMed, 467 on Scopus and 369 on Web Of Science. 67 articles were included, collecting a total of 32,934 robust subjects and 6864 frail subjects. C-reactive protein (CRP) (Standardized Mean Difference (SMD): 0.49 CI 95% [0.37-0.61]) was significantly higher in the frail group whereas hemoglobin (SMD: -0.67[-0.90; -0.44]), albumin (SMD: -0.62[-0.84; -0.41]), 25-hydroxyvitamin D (25OHD) (SMD: -0.43 [-0.64; -0.21]) and, in men, free testosterone (SMD: -0.77 [-1.05; -0.49]) were significantly lower in the frail group.

CONCLUSION

We found 5 biomarkers that were associated with frailty (CRP, hemoglobin, albumin, 25OHD and free testosterone in men) belonging to multiple physiological systems. Further cohort studies are needed to verify their ability to screen for frailty.

Influence of serum 25-hydroxyvitamin D levels, fat-free mass, and fat mass on bone density, geometry and strength, in healthy young and elderly adults

PURPOSE

The association between serum 25-hydroxyvitamin D (25-OHD) levels and cortical/trabecular bone parameters has been explored in the elderly, but less so in younger adults; body composition may also influence bone parameters across the life span. We aimed to investigate, with peripheral quantitative computerized tomography (pQCT), the relationship between serum 25-OHD levels and bone geometry and strength and, at the same time, to explore the influence of fat mass and fat-free mass on bone parameters, for the tibia and radius, in healthy young and elderly adults.

METHODS

The study involved 149 healthy adults grouped by age: 65 were under 65 years old, and 84 were older. All participants were assessed in terms of: clinical history; serum 25-OHD levels; fat-free mass (FFM) and fat mass (FM), measured with DXA; total and cortical bone cross-sectional area (CSA, CSAc), and trabecular and cortical bone mineral density (BMDt, BMDc); and fracture load x and y for the tibia and radius, measured with pQCT.

RESULTS

In the younger group, the association between 25-OHD levels and bone parameters did not remain as significant for any parameters after multivariate adjustment. In the elderly, 25-OHD correlated with CSAc (partial R² = 0.33), fracture load x (partial R² = 0.54), and fracture load y (partial R² = 0.46) for the radius, and marginally with BMDt (partial R² = 0.09; B-H adjusted p < 0.05 for all) for the tibia. FFM correlated with all bone parameters in both age groups. In the elderly group alone, FM correlated with BMDt at the tibia (r = 0.25, p < 0.05), with CSA at both sites (radius r = -0.25, p < 0.05; tibia r = -0.32, p < 0.001), and with fracture load y on the radius (r = -0.22, p < 0.05).

CONCLUSION

While serum 25-OHD levels correlated only weakly with bone parameters in younger adults, a significant relationship was observed for elderly people. Fat-free mass showed positive simple correlation with pQCT-derived bone parameters in both age groups except with BMDc in the younger group. Further longitudinal studies are needed to clarify these relationships.

Low 25-hydroxyvitamin D levels and the risk of frailty syndrome: a systematic review and dose-response meta-analysis

Background

Vitamin D deficiency and frailty are common with aging. Previous studies examining vitamin D status and frailty have produced mixed results, and in particular, the shape of the association has not been well established. We examined the association between 25-hydroxyvitamin D (25OHD) serum levels and frailty by performing a systematic review and dose-response meta-analysis.

Methods

We searched the PubMed, EMBASE and Cochrane Library databases of Elsevier through February 2017. Cross-sectional and cohort studies that reported adjusted risk ratios with 95% confidence intervals (CI) for frailty with ≥3 categories of 25OHD serum levels were selected. Data extraction was performed independently by two authors. The reported risk estimates for 25OHD categories were recalculated, employing a comprehensive trend estimation from summarized dose-response data.

Results

The pooled risk estimate of frailty syndrome per 25 nmol/L increment in serum 25OHD concentration was 0.88 (95% CI = 0.82–0.95, I² = 86.8%) in the 6 cross-sectional studies and 0.89 (95% CI = 0.85–0.94, I² = 0.0%) in the 4 prospective cohort studies. Based on the Akaike information criteria (AIC), a linear model was selected (AIC for the nonlinear model: − 5.4, AIC for the linear model: − 6.8 in the prospective cohort studies; AIC for the linear model: − 13.6, AIC for the nonlinear model: − 1.77 in the cross-sectional studies).

Conclusions

This dose-response meta-analysis indicates that serum 25OHD levels are significantly and directly associated with the risk of frailty. Further studies should address the underlying mechanisms to explain this relationship and to determine whether vitamin D supplementation is effective for preventing frailty syndrome.

Electronic supplementary material

The online version of this article (10.1186/s12877-018-0904-2) contains supplementary material, which is available to authorized users.

Vitamin D Deficiency and Insufficiency Prevalence in the West of Ireland - A Retrospective Study

OBJECTIVES

Vitamin D plays an important role in calcium homeostasis and is essential for normal bone growth and remodeling. Previous studies of acutely ill and institutionalized older women in Galway revealed that vitamin D insufficiency is extremely common. We aimed to evaluate age and gender-related rates of vitamin D insufficiency and deficiency in adult patients attending their General Practitioners in the same region.

DESIGN

A retrospective cohort study.

SETTING

General practices in Galway, a city located on the west coast of Ireland, latitude 53.17 North.

PARTICIPANTS

A total of 15,708 consecutive blood samples from adults attending their General Practitioners between January 2013 and December 2014 were sent to the Clinical Biochemistry Laboratory in the University Hospital Galway for vitamin D level testing. 73% were from women.

INTERVENTION

Data were collected and grouped according to age, sex and season. Vitamin D levels (25OHD) were categorised into deficiency (<25nmol/L), insufficiency (25-50nmol/L) and sufficiency ( >50nmol/L).

MEASUREMENTS

Median and interquartile range were reported as vitamin D levels were not normally distributed. Descriptive statistics were performed using STATA/MP 13.1 for Mac.

RESULTS

While vitamin D levels were sufficient in 56.4% (n=8,496), they were insufficient in 32.4% (n=4,891) and deficient in 11.2% (n=1,691). Of the deficient group, 19%( 325) had levels <15nmol/L consistent with profound deficiency. Men were more likely than women to be deficient (12% (n=489) vs. 10.9% (n=1,202)) and insufficient (38.0% (n=1,550) vs. 30.4% (n=3,341)) (p<0.01). Highest rates of deficiency were seen in those 81-97 years (19.4% (n=136)) and 18-40 years (13.8% (n=543)), the former group showing less seasonal variation.

CONCLUSION

Overall prevalence of insufficiency is similar to those in national and European studies published recently. However, there is a high possibility that those most vulnerable to vitamin D deficiency were underrepresented in this cohort, when results from previous studies in the same region are considered. Further prospective studies are needed to guide treatment with supplementation of vitamin D for appropriate subgroups.