Independent Association of Vitamin D With Physical Function in People With Chronic Spinal Cord Injury

Does irisin mediate metabolic effects of androgen deficiency? A cross-sectional study in men with chronic spinal cord injury

STUDY DESIGN

Retrospective study.

OBJECTIVES

To check the hypothesis that irisin could mediate systemic metabolic effects of testosterone in men with chronic spinal cord injury (SCI).

SETTING

Spinal Unit of the San Raffaele Institute in Sulmona.

METHODS

Fifteen men with chronic SCI admitted to a rehabilitation program were involved. They underwent clinical and biochemical evaluations. Irisin levels were measured with a high-sensitivity ELISA kit. Free testosterone levels were calculated (cFT) from total testosterone, sex hormone binding globulin, and albumin concentrations using the Vermeulen formula.

RESULTS

Androgen deficiency (total testosterone <3 ng/ml and cFT <64 pg/ml) was found in 53% of participants and was associated with significantly lower irisin levels, higher body mass index (BMI), and higher triglycerides. Participants were engaged in significantly poorer leisure time physical activity (LTPA). Circulating irisin correlated with cFT (r = 0.55; p = 0.03) and both were negatively correlated with triglycerides levels, homeostatic model assessment of insulin resistance (HOMA-IR) and systemic inflammation, as assessed by erythrocyte sedimentation rate (ESR). Correlations with irisin did not reach statistical significance for either BMI (r = -0.40; p = 0.13) or LTPA (r = 0.46; p = 0.08). In bivariate linear regression models, lower irisin levels were significantly associated with higher triglycerides (β = -0.46; 95% CI: -0.75 to -0.16), HOMA-IR (β = -0.32; 95% CI: -0.63 to -0.004) and ESR (β = -0.89; 95% CI: -1.69 to -0.10) independently of cFT. Conversely, the negative associations of cFT with the same variables were lost after adjustment for irisin levels.

CONCLUSIONS

Spinal cord-injured men with androgen deficiency exhibit lower levels of irisin, which could mediate the systemic effects of testosterone.

Correlates of metabolic syndrome in people with chronic spinal cord injury

PURPOSE

We aimed at identifying clinical risk factors or early markers of metabolic syndrome (MetS) in people with spinal cord injury (SCI) that would facilitate a timely diagnosis and implementation of preventive/therapeutic strategies.

METHODS

One hundred sixty-eight individuals with chronic (> 1 year) SCI underwent clinical and biochemical evaluations. MetS was diagnosed according to modified criteria of the International Diabetes Federation validated in people with SCI. Wilcoxon rank-sum test and χ2 test were used to compare variables between groups with and without MetS. Multiple logistic regression analysis was performed to reveal independent associations with MetS among variables selected by univariate linear regression analyses.

RESULTS

MetS was diagnosed in 56 of 132 men (42.4%) and 17 of 36 women (47.2%). At univariate regression analyses, putative predictors of MetS were an older age, a higher number of comorbidities, a lower insulin-sensitivity, the presence and intensity of pain, a shorter injury duration, a poorer leisure time physical activity (LTPA) and an incomplete motor injury. At the multiple logistic regression analysis, a significant independent association with MetS only persisted for a poorer LTPA in hours/week (OR: 0.880, 95% CI 0.770, 0.990) and more severe pain symptoms as assessed by the numeral rating scale (OR: 1.353, 95% CI 1.085, 1.793).

CONCLUSION

In people with chronic SCI, intense pain symptoms and poor LTPA may indicate a high likelihood of MetS, regardless of age, SCI duration, motor disability degree, insulin-sensitivity and comorbidities.

Impact of vitamin D on the prognosis after spinal cord injury: A systematic review

Vitamin D (VitD) insufficiency is a worldwide health problem and affects billions of people. Spinal cord injury (SCI) patients seem more susceptible to developing suboptimal levels of VitD. However, the literature regarding its impact on the prognosis of SCI is limited. Thus, in this review, we systematically investigated the published studies via a combination of keywords associated with SCI and VitD in four medical databases (Medline, Embase, Scopus, and Web of Science). All included studies were analyzed, and selected clinical data on the prevalence of VitD insufficiency (serum 25-hydroxyvitamin D < 30 ng/ml) and deficiency (serum 25-hydroxyvitamin D < 20 ng/ml) were collected for further meta-analysis via random effects. Through literature review, a total of 35 studies were eligible and included. The meta-analysis of VitD status (13 studies, 1,962 patients) indicated high prevalence of insufficiency (81.6% [75.7, 87.5]) and deficiency (52.5% [38.1, 66.9]) after SCI. Besides, low levels of VitD were reported to be associated with a higher risk of skeletal diseases, venous thromboembolism, psychoneurological syndromes, and chest illness after injury. Existing literature suggested that supplemental therapy might act as an adjuvant treatment to facilitate post-injury rehabilitation. Non-human experimental studies highlighted the neuroprotective effect of VitD, which was associated with enhancing axonal and neuronal survival, suppressing neuroinflammation, and modulating autophagy. Therefore, the current evidence suggests that the prevalence of VitD insufficiency is high in the SCI population, and low-level VitD may impair functional restoration after SCI. VitD supplemental treatment may have potential benefits to accelerate rehabilitation in mechanistically related processes after SCI. However, due to the limitation of the available evidence, more well-designed randomized controlled trials and mechanism experimental research are still needed to validate its therapeutic effect, elucidate its neuroprotective mechanism, and develop novel treatments.

Vitamin D supplementation in chronic spinal cord injury (VitD-SCI): study protocol for a randomised controlled trial

INTRODUCTION

Vitamin D insufficiency, a vitamin D status or serum 25(OH)D concentration of ≤75 nmol/L, is highly prevalent in individuals with a spinal cord injury (SCI). Vitamin D is important for the functioning of the musculoskeletal, immune and respiratory systems, which are relevant determinants of secondary health conditions in SCI. An insufficiency should be treated with vitamin D supplementation. However, there is a lack of evidence regarding the optimal dosage and duration of vitamin D supplementation for individualised and long-term management of the vitamin D status in the context of SCI. This paper presents the protocol for the vitamin D supplementation in chronic spinal cord injury (VitD-SCI) trial that aims to investigate the effect of a 12-month intake of vitamin D supplementation on vitamin D status as well as on several secondary parameters among individuals with a chronic SCI.

METHODS AND ANALYSES

The VitD-SCI trial is a randomised, placebo-controlled, double-blinded, parallel-group, superiority trial, conducted at the Swiss Paraplegic Centre. A total of 45 participants living with an SCI for at least 3 years (chronic SCI) and a vitamin D insufficiency at the first study visit, will be randomly assigned to one of three intervention groups. Participants receive either a monthly dosage of 24 000 IU or 48 000 IU vitamin D or a placebo for 12 months. Measurements taking place every 3 months include the assessment of vitamin D status (primary outcome) as well as bone mineral density, handgrip strength, fatigue, mood, pain and pressure injuries (secondary outcomes). Safety and tolerance of vitamin D supplementation will also be evaluated.

ETHICS AND DISSEMINATION

The Swiss Ethics Committee for Northwest/Central Switzerland (EKNZ, 2020-01493) and the Swiss Agency for Therapeutic Products (Swissmedic, 2020DR3150) approved this study. Findings will be disseminated through peer-reviewed publications.

TRIAL REGISTRATION NUMBERS

NCT04652544 and SNCTP000004032.

Erectile Dysfunction Is the Main Correlate of Depression in Men with Chronic Spinal Cord Injury

Depression is the most prevalent psychological issue after a spinal cord injury (SCI) and is associated with noticeable disability, mortality and health expenditure. As SCI mainly occurs in sexually active men at a young age, and can lead to them suffering from an organic neurogenic erectile dysfunction (ED), we supposed that ED could be a major correlate of depressive status in men with SCI. As documented by a Beck Depression Inventory-II (BDI-II) score ≥14, depression was reported in 17 out of 57 men with a chronic SCI (29.8%). They exhibited a significantly higher prevalence of ED and a more severe bowel and bladder dysfunction when compared to the group without depression. At the multiple logistic regression analysis, depression showed a significant independent association with ED (OR = 19.0, 95% CI: 3.1, 203.3; p = 0.004) and, to a lesser extent, with a severe impairment of bowel and bladder function (OR = 0.84; 95% CI: 0.72, 0.94; p = 0.01). Depression was observed in 43.7% of men with ED and only in 12.0% of those without ED (p = 0.002). In conclusion, healthcare providers should give the right level of importance to the management of ED in men with SCI, as this represents a major independent correlate of depression, which, in turn, might hinder physical rehabilitation and exacerbate physical health issues related to SCI.

Relationship of Vitamin D status with testosterone levels: a systematic review and meta-analysis

PURPOSE

Despite a biological plausibility of a direct link between low vitamin D and androgen deficiency, the association remains inconclusive in epidemiological studies. Therefore, this systematic review and meta-analysis of case-control studies aim to assess whether and in what populations such an association can be demonstrated.

METHODS

A systematic search was performed in PubMed, EMBASE, Cochrane Library, Web of science, Science Direct, and CINAHL. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) in total testosterone (TT) levels between men with 25-hydroxyvitamin D (25(OH)D) <20 and ≥20 ng/mL were combined using random-effects models. Funnel plot and trim-and-fill analysis were used to assess publication bias. Heterogeneity source was explored by a sub-group analysis according to health-related characteristics of the study populations.

RESULTS

Eighteen included studies collectively gave information on 9892 men with vitamin D deficiency and 10,675 controls. The pooled SMD revealed a slight, albeit just significant, positive association between 25(OH)D and TT (pooled SMD: -0.23, 95% CI: -0.45 to -0.01; P = 0.04) with a large between-study heterogeneity (I² = 98%, P_{for heterogeneity} < 0.00001). At the sub-group analysis, a significant positive association, along with noticeable decrease in heterogeneity, could only be demonstrated in studies of patients with frailty states (pooled SMD: -0.19; 95% CI: -0.27, -0.10,  P < 0.0001; I² = 51%, P_{for heterogeneity} = 0.06). A sensitivity analysis revealed a high stability of the result and the trim-and-fill adjustment for publication bias did not affect pooled estimate.

CONCLUSIONS

Both hypovitaminosis D and androgen deficiency should be regarded as markers of a poor health status, sharing common underlying aetiologies and risk factors.

Testosterone, level of the lesion and age are independently associated with prostate volume in men with chronic spinal cord injury

PURPOSE

Although men with spinal cord injury (SCI) exhibit a prostate volume significantly smaller compared to age-matched able-bodied men, the independent association of lower prostate volume with its putative determinants has never been analyzed in this population. This study was designed to identify variables independently associated with prostate volume in men with chronic SCI.

METHODS

In this cross-sectional study, prostate volume of 138 men with chronic (> 1 years) SCI, aged 54.5 (25th-75th percentile: 36.0-66.0) years, was evaluated with trans-rectal ultrasonography. All patients underwent a complete neurological exam, as well as biochemical and hormonal assessment, including total testosterone (TT) levels. Free testosterone levels were calculated (cFT) by the Vermeulen formula.

RESULTS

The median prostate volume was 23.4 mL. At the univariate analysis, a larger prostate volume was associated with higher TT (p = 0.00001) and cFT (p = 0.001), SCI level below T12 (p = 0.007), more advanced age (p = 0.04), lower body mass index (p = 0.04), higher functional independence score (p = 0.06), higher values of prostate-specific antigen (p = 0.12) and shorter duration of the injury (p = 0.21). However, at the multiple regression analyses, an independent and positive association only persisted between the prostate volume with either TT or cFT levels, and, to a lesser extent, with age and a level of spinal lesion below T12. A prostate volume below the median value was observed in 91.4% (32/35) of patients with both androgen deficiency (TT < 264 ng/dL) and spinal lesion level ≥ T12, but only in 16.5% (2/12) of patients with both normal androgen levels and spinal lesion level below T12 (p < 0.001).

CONCLUSIONS

Our data indicate that lower testosterone levels and, to a lesser extent, a younger age and a spinal lesion level ≥ T12 represent the only variables exhibiting an independent association with a smaller prostate volume in men with SCI.

B Cell-Activating Factor Is Associated with Testosterone and Smoking Status in Non-Ambulatory Men with Chronic Spinal Cord Injury

B cell-mediated autoimmunity may contribute to poor neurological outcomes after spinal cord injury (SCI). B cell-activating factor (BAFF) is a key cytokine involved in B cell development, proliferation, activation, and survival whose expression is elevated in men with chronic SCI. The aim of this study was to assess factors associated with circulating BAFF in non-ambulatory males with chronic SCI. We assessed the association between clinical and demographic factors, health habits, and circulating BAFF levels in a convenience sample of 43 non-ambulatory men with chronic spinal cord injury (≥ 1 year post-injury). Serum BAFF and total testosterone levels were quantified by enzyme-linked immunosorbent assay. Body composition was determined by whole body dual-energy X-ray absorptiometry. In multivariable models, active smokers had significantly greater BAFF levels than former/nonsmokers (871 pg/mL vs. 665 pg/ml, p = 0.002). BAFF decreased 36 ± 11.1 pg/mL for every 1 ng/mL increase in total testosterone (p = 0.002). This model explained 41% of the variation in circulating BAFF levels (model p < 0.0001). Our findings suggest that modifiable health habits may be associated with elevated BAFF levels in men with non-ambulatory chronic SCI. Further, the significant and independent negative association between testosterone levels and BAFF would suggest a link between androgen deficiency and autoimmunity observed in SCI via modulation of BAFF and B cell numbers. This points toward BAFF as a potential biomarker of injury severity and a target of therapies designed to reduce neuroinflammation and improve neurological outcomes after SCI.

Venous Thromboembolism is Associated With Lack of Vitamin D Supplementation in Patients With Spinal Cord Injury and Low Vitamin D Levels

BACKGROUND

The role of vitamin D in the pathogenesis of venous thromboembolism (VTE) and prevalence of low vitamin D (LVitD) in spinal cord injury (SCI) has motivated vitamin D testing and supplementation. This is an exploratory study of data collected at a time before the routine clinical practice of vitamin D supplementation, allowing for evaluation of the natural history of vitamin D levels in patients with SCI.

OBJECTIVE

To determine if vitamin D supplementation in persons with SCI and LVitD levels is associated with decreased prevalence of VTE.

DESIGN

Retrospective cohort study.

SETTING

Rehabilitation Center at a Level I Trauma Center.

PARTICIPANTS

Patients with SCI admitted to acute inpatient rehabilitation (N = 282).

MAIN OUTCOME MEASURES

VTE prevalence in patients with LVitD levels, grouped by presence or absence of vitamin D supplementation.

RESULTS

Of the acute inpatient SCI population, 80% (227/282) of patients demonstrated vitamin D levels <30 ng/mL (LVitD). Although the incidence of VTE was almost double in the LVitD group, 19% (43/227) of the patients in the LVitD group had VTE versus 9% (5/55) of patients with vitamin D levels ≥30 ng/mL (normal VitD [NVitD]); this difference was not statistically significant (P = .108, Cramer's V = .104). When the role of vitamin D supplementation was analyzed, individuals in the LVitD group who received no vitamin D supplementation (LVitDSuppNegative) had a higher incidence of VTE (statistically significant) compared to the LVitD group with vitamin D supplementation (LVitDSuppPositive) (24% [42/178] vs. 2% [1/49]) (P < .001, Cramer's V = .226). In post hoc exploratory analyses, the VTE rate of patients in the LVitDSuppNegative group was noted to be significantly higher than that in all other patient groups combined (P < .001, Cramer's V = .229). A binary logistic regression model incorporating clinical covariates also showed this grouping to be significant.

CONCLUSION

A significant association appears to exist between lack of vitamin D supplementation and VTE occurrence in persons with acute SCI and LVitD levels.

LEVEL OF EVIDENCE

III.

Can the positive association of osteocalcin with testosterone be unmasked when the preeminent hypothalamic-pituitary regulation of testosterone production is impaired? The model of spinal cord injury

PURPOSE

Osteocalcin (OCN), released from the bone matrix during the resorption phase, in its undercarboxylated form, stimulates testosterone (T) biosynthesis in mouse and a loss-of-function mutation of its receptor was associated with hypergonadotropic hypogonadism in humans. Nevertheless, when population-based studies have explored the OCN-T association, conflicting results have been reported. Hypothesizing that the evidence of a positive association between OCN and T could have been hindered by the preeminent role of a well-functioning hypothalamus-pituitary axis in promoting T biosynthesis, we explored this association in men with chronic spinal cord injury (SCI), exhibiting high prevalence of non-hypergonadotropic androgen deficiency.

METHODS

Fifty-five consecutive men with chronic SCI underwent clinical/biochemical evaluations, including measurements of total T (TT), OCN and 25(OH)D levels. Free T (FT) levels were calculated by the Vermeulen formula. Comorbidity was scored by Charlson comorbidity index (CCI).

RESULTS

A biochemical androgen deficiency (TT < 300 ng/dL) was observed in 15 patients (27.3%). TT was positively correlated with OCN, 25(OH)D and leisure time physical activity and negatively correlated with age, BMI and CCI. OCN was also positively correlated with calculated FT and negatively correlated with BMI and HOMA-IR. At the multiple linear regression analyses, a positive association of OCN with TT and calculated FT persisted after adjustment for confounders.

CONCLUSIONS

The positive association here found between OCN and T levels in men with chronic SCI reinforces the notion that a bone-testis axis is also functioning in humans and suggests that it can be unmasked when the preeminent hypothalamic-pituitary regulation of T production is impaired.

Associations between vitamin D, adiposity, and respiratory symptoms in chronic spinal cord injury

Context/Objective Persons with chronic spinal cord injury (SCI) have an increased risk of respiratory-related morbidity and mortality and chronic respiratory symptoms are clinical markers of future respiratory disease. Therefore, we sought to assess potentially modifiable factors associated with respiratory symptoms, with a focus on circulating vitamin D and measures of body fat. Design Cross-sectional study. Setting Veterans Affairs Medical Center. Participants Three hundred forty-three participants (282 men and 61 women) with chronic SCI participating in an epidemiologic study to assess factors influencing respiratory health recruited from VA Boston and the community. Methods Participants provided a blood sample, completed a respiratory health questionnaire, and underwent dual x-ray absorptiometry (DXA) to assess % body fat. Logistic regression was used to assess cross-sectional associations between respiratory symptoms and plasma vitamin D and measures of body fat with adjustment for a number of potential confounders. Outcome Measures Chronic cough, chronic phlegm, any wheeze, persistent wheeze. Results After adjustment for a number of confounders (including smoking), participants with greater %-android, gynoid, trunk, or total body fat had increased odds ratios for any wheeze and suggestive associations with persistent wheeze, but not with chronic cough or phlegm. Vitamin D levels were not associated with any of the respiratory symptoms. Conclusion Increased body fat, but not vitamin D, was associated with wheeze in chronic SCI independent of a number of covariates.

Effectiveness of two vitamin D3 repletion protocols on the vitamin D status of adults with a recent spinal cord injury undergoing inpatient rehabilitation: a prospective case series

Study design

Prospective case series.

Objectives

To assess the effectiveness and safety of two vitamin D₃ repletion protocols given to individuals with spinal cord injury (SCI).

Setting

Publicly-funded intensive inpatient rehabilitation center, Montreal, Canada.

Methods

Thirty adults with recent SCI complete or incomplete sensorimotor impairments were recruited upon admission from designated regional SCI trauma centers. Participants with serum 25OHD ≤ 30 nmol/L were given 10,000 IU of weekly and 1000 IU of daily vitamin D₃ for 36.8 ± 11.9 days (higher dose: HD). Subjects with serum 25OHD > 30 nmol/L received 1000 IU of daily vitamin D₃ for 38.2 ± 11.6 days (lower dose: LD). Outcomes were changes in 25OHD levels from baseline to the end of the study period and safety outcomes. Thresholds for vitamin D deficiency, insufficiency and sufficiency were: 25OHD levels ≤30 nmol/L, 30-74 nmol/L, and ≥75 nmol/L.

Results

At baseline, 34 and 66% of participants had serum 25OHD < 30 and >30 nmol/L. Both protocols induced a rise in serum 25OHD with a greater increase in the HD vs. LD regimen (31.4 [95% CI: 16.7, 46.0] vs. 11.7 nmol/L [95% CI: 2.2, 21.2]). None of the participants given the HD remained vitamin D deficient, but only one achieved vitamin D sufficiency. Nearly all individuals on the LD regimen remained vitamin D insufficient with only two reaching vitamin D sufficiency. No adverse effects were observed over the course of the supplementation.

Conclusions

Although 1000 IU of daily vitamin D₃ alone or in combination with weekly 10,000 IU for an average of 37.6 days increased serum 25OHD, they were unsuccessful in improving the impaired vitamin D status during inpatient rehabilitation of individuals with a recent SCI.

Effect of Vitamin D Supplementation on 25(OH)D Status in Elite Athletes With Spinal Cord Injury

Recent studies suggest that a substantial proportion of athletes with spinal cord injury have insufficient 25(OH) vitamin D (25(OH)D) status, which may be associated with decreased muscle strength. This study consisted of two parts: (a) to examine the effects of a 12- to 16-week vitamin D₃ supplementation protocol on 25(OH)D concentration and (b) to determine whether subsequent 25(OH)D status impacts muscle performance in elite athletes with spinal cord injury. Thirty-four members (age: 33 ± 15 years, weight: 69.6 ± 28.2 kg, and height: 170.2 ± 25.4 cm) of the U.S. and Canadian Paralympic program participated in the study. 25(OH)D concentrations and performance measures (handgrip strength and 20-m wheelchair sprint) were assessed pre- and postsupplementation. Participants were assigned a vitamin D₃ supplementation protocol based on initial 25(OH)D concentrations. Participants with deficient 25(OH)D status (<50 nmol/L) received 50,000 IU/week for 8 weeks, and participants with insufficient status (50-75 nmol/L) received 35,000 IU/week for 4 weeks, after which both received a maintenance dose of 15,000 IU/week. Participants with sufficient status (>75 nmol/L) received the maintenance dose of 15,000 IU/week. 25(OH)D concentrations increased significantly (p < .001; 66.3 ± 24.3 nmol/L and 111.3 ± 30.8 nmol/L pre- and postsupplementation, respectively). About 26% of athletes had sufficient 25(OH)D concentrations presupplementation, and 91% had sufficient concentrations postsupplementation. About 62% of participants improved handgrip strength postsupplementation with no change in 20-m wheelchair sprint performance. The supplementation protocol was effective for achieving sufficient vitamin D concentrations in elite athletes with spinal cord injury.

Creatine or vitamin D supplementation in individuals with a spinal cord injury undergoing resistance training: A double-blinded, randomized pilot trial

PURPOSE

Determine whether creatine or vitamin D supplementation improves muscle strength in individuals with spinal cord injury undergoing resistance training.

METHODS

Thirteen male and one female with spinal cord injury, from two Portuguese rehabilitation centers, were randomized to creatine (3g daily), vitamin D (25000 IU each two weeks) or placebo group in a double-blind design. All participants performed progressive resistance training during eight weeks. The outcome measures, obtained at baseline and after intervention, included: Sum of four skinfolds; Corrected arm muscle area; Seated medicine ball throw; Handgrip strength with dynamometer; Manual wheelchair slalom test and one repetition maximum for Chest press, Triceps, Pec deck and Lat pulldown. Vitamin D levels were obtained in all participants before and after intervention.

RESULTS

71.4% of participants had deficit values of vitamin D. The corrected arm muscle area improved significantly (p<0.05) in creatine group relatively to the control group. There was a significant correlation (p<0.05) between the one repetition maximum Pec deck and levels of vitamin D.

CONCLUSIONS

Supplementation with creatine may improve muscle strength parameters in individuals with spinal cord injury. Vitamin D deficiency is highly prevalent in this population. It is recommended an initial screening of vitamin D levels at the beginning of the physical rehabilitation process.

The Role of Vitamin D in the Immune System as a Pro-survival Molecule

PURPOSE

Vitamin D is a fascinating and attractive molecule that has gained particular attention in medicine in recent years. Its immunomodulatory and anti-inflammatory potential might resemble the activity of many nature-derived molecules (eg, flavonoids), but its role in biology was selected during a long evolutionary pathway to dampen the damaging effect of cell stress response and of the immune reaction. In this sense, this molecule can be considered an ancient hormone that serves, in its primary role, as a pro-survival agent. The goal of this review was to elucidate this topic.

METHODS

The article reviews current literature on the field, focusing on issues regarding the role of vitamin D in immunity.

FINDINGS

Vitamin D participates in the survival machinery used by the cell, and in particular it plays a major role in synchronizing calcium oscillatory signaling to allow cell autophagy or apoptosis during a stress response.

IMPLICATIONS

Vitamin D should be better highlighted in its molecular action and vitamin D receptor genomics to conceive a more suited therapeutic supplementation protocol in clinics.

Lower Vitamin D Levels Are Associated With Depression in People With Chronic Spinal Cord Injury

OBJECTIVES

To determine (1) whether the serum concentration of 25-hydroxy vitamin D (25(OH)D₃) was associated with depression levels in people with chronic spinal cord injury (SCI) and (2) whether any observed association was independent of potential confounders.

DESIGN

Cross-sectional study.

SETTING

Rehabilitation institute.

PARTICIPANTS

Patients with chronic SCI (N=100) recruited consecutively.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Patients underwent clinical and biochemical evaluations, including assessment of 25(OH)D₃ levels and the presence and severity of depressive symptoms, by using the interviewer-assisted self-report Beck Depression Inventory-II (BDI-II).

RESULTS

Depression (BDI-II score ≥14) was observed in 15 of 28 women (53.6%) and 18 of 72 men (25.0%) of the study population. They exhibited significantly lower 25(OH)D₃ levels, lower functional independence degree in performing activities of daily living, poorer engagement in leisure time physical activity, and higher body mass index. Lower 25(OH)D₃ levels were associated with higher BDI-II scores as well as with the occurrence of depression. These associations persisted after adjustment for all significant predictors of the BDI-II score that were selected, as possible confounders, by univariate analysis. In receiver operating characteristic analysis, a 25(OH)D₃ level of <9.99ng/mL had the highest accuracy in discriminating patients with depression.

CONCLUSIONS

In people with chronic SCI, an inverse association exists between serum 25(OH)D₃ levels and depressive symptoms, widely independent of potential confounders, especially those, peculiar to this population, that can mediate the effects of depression on vitamin D levels.

Vitamin D and spinal cord injury: should we care?

STUDY DESIGN

Narrative review.

OBJECTIVES

This review provides an overview of the etiological factors and consequences of vitamin D insufficiency in relation to spinal cord injury (SCI) as well as important considerations for vitamin D supplementation.

SETTING

Montreal, Canada.

METHODS

Literature search.

RESULTS

Vitamin D insufficiency is common in SCI individuals owing to the presence of many contributing factors including limited sun exposure and intake, use of medication and endocrine perturbations. Although there are several biological plausible mechanisms by which vitamin D may act upon musculoskeletal and cardiometabolic health, the impact of vitamin D insufficiency on such systems remains ill defined in SCI. In the absence of guidelines for the management of vitamin D insufficiency in this high-risk population and in an attempt to provide clinical guidance, considerations for vitamin D supplementation such as the type of vitamin D, dosing regimens and toxicity are discussed and tentative recommendations suggested with particular reference to issues faced by SCI patients.

CONCLUSION

Although high rates of vitamin D insufficiency are encountered in SCI individuals, its consequences and the amount of vitamin D required to prevent insufficiency are still unknown, indicating a need for more intervention studies with well-defined outcome measures. Routine screening and monitoring of vitamin D as well as treatment of suboptimal status should be instituted in both acute and chronic setting. The close interactions between vitamin D and related bone minerals should be kept in mind when supplementing SCI individuals, and practices should be individualized with clinical conditions.

25(OH)D Status of Elite Athletes with Spinal Cord Injury Relative to Lifestyle Factors

Background: Due to the potential negative impact of low Vitamin D status on performance-related factors and the higher risk of low Vitamin D status in Spinal Cord Injury (SCI) population, research is warranted to determine whether elite athletes with SCI have sufficient 25(OH)D levels. The purposes of this study were to examine: (1) the seasonal proportion of vitamin D insufficiency among elite athletes with SCI; and (2) to determine whether lifestyle factors, SCI lesion level, and muscle performance/function are related to vitamin D status in athletes with SCI. Methods: Thirty-nine members of the Canadian Wheelchair Sports Association, and the US Olympic Committee Paralympic program from outdoor and indoor sports were recruited for this study. Dietary and lifestyle factors, and serum 25(OH)D concentrations were assessed during the autumn (October) and winter (February/March). An independent t-test was used to assess differences in 25(OH)D status among seasons, and indoor and outdoor sports in the autumn and winter, respectively. Results: Mean ± SD serum 25(OH)D concentration was 69.6 ± 19.7 nmol/L (range from 30 to 107.3 nmol/L) and 67.4 ± 25.5 nmol/L (range from 20 to 117.3 nmol/L)in the autumn and winter, respectively. In the autumn, 15.4% of participants were considered vitamin D deficient (25(OH)D < 50 nmol/L) whereas 51.3% had 25(OH)D concentrations that would be considered insufficient (<80 nmol/L). In the winter, 15.4% were deficient while 41% of all participants were considered vitamin D insufficient. Conclusion: A substantial proportion of elite athletes with SCI have insufficient (41%–51%) and deficient (15.4%) 25(OH)D status in the autumn and winter. Furthermore, a seasonal decline in vitamin D status was not observed in the current study.