Vitamin D Binding Protein and Vitamin D Levels in Multi-Ethnic Population

Introduction

Low levels of 25-hydroxyvitamin D (25(OH)D) has been associated with many negative health outcomes including falls and fractures. 25(OH)D is largely bound to vitamin D binding protein (VDBP). There is increasing evidence that free or bioavailable 25(OH)D may be a better measure of vitamin D deficiency.

Objective

To determine the prevalence of 25(OH)D deficiency and VDBP levels in multi-ethnic population, and its impact on muscle strength.

Design and methods

Cross-sectional study of older adults in Western region of Singapore. 295 participants from three ethnic groups were selected from the Healthy Older People Everyday (HOPE) cohort for measurements of total 25(OH)D and VDBP levels. Total 25(OH)D, VDBP, frailty status, Timed-Up-and-Go (TUG) and grip strength (GS) were assessed. Albumin, free and bioavailable 25(OH)D were only available for 256 participants.

Results

53% of Malay and 55% of Indians were deficient in 25(OH)D compared with 18.2% of ethnic Chinese participants. Chinese also had higher total 25(OH)D concentrations with a mean of 29.1 ug/l, (p = <0.001). Chinese had the lowest level of VDBP (169.6ug/ml) followed by Malay (188.8 ug/ml) and Indian having the highest (220.1 ug/ml). Calculated bioavailable and free 25(OH)D levels were significantly higher in Chinese, followed by Malays and Indians, which also correlated with better grip strength measures amongst the Chinese.

Conclusion

The Malays and Indians had overall lower free, bioavailable and total 25(OH)D compared with ethnic Chinese. Chinese ethnic group also had the lowest VDBP and better overall grip strength.

     

Physical Performance and Serum 25(OH)Vitamin D Status in Community Dwelling Old Mobility Limited Adults: A Cross-Sectional Study

Objectives

To examine the potential association between serum 25(OH) vitamin D and the performance on the Short Physical Performance Battery (SPPB) including the sub-components; five repeated chair stands test, 4 meters walk test and balance in older mobility-limited community-dwelling men and women.

Design

A cross sectional study was performed in American and Swedish subjects who were examined for potential participation in a combined exercise and nutrition intervention trial. Logistic regression analysis and linear regression analyses were performed to evaluate the association for 25(OH)D with the overall score on the SBBP, chair stand, gait speed and balance.

Participants

Community-dwelling (mean age 77.6 ± 5.3 years) mobility limited American (n=494) and Swedish (n=116) females (59%) and males.

Measurements

The SPPB (0-12 points) includes chair stand (s), gait speed (m/s) and a balance test. Mobility limitation i.e., SPPB score ≤ 9 was an inclusion criterion. A blood sample was obtained to measure serum 25(OH)vitamin D concentrations.

Results

No clear association of 25(OH)D with SPPB scores was detected either when 25(OH)D was assessed as a continuous variable or when categorized according to serum concentrations of <50, 50-75 or <75 nmol/L. However, when analyzing the relationship between 25(OH)D and seconds to perform the chair stands, a significant quadratic relationship was observed. Thus, at serum levels of 25(OH)D above 74 nmol/L, higher concentrations appeared to be advantageous for the chair stand test, whereas for serum levels below 74 nmol/L this association was not observed.

Conclusion

This cross- sectional study lacked clear association between serum 25(OH)D and physical performance in mobility limited adults. A potentially interesting observation was that at higher serum levels of 25(OH)D a better performance on the chair stand test was indicated.

     

Factors influencing serum 25-hydroxivitamin D levels and other bone metabolism parameters in healthy older women

Objective

Older women have frequently low serum 25-hydroxivitamin D (25[OH]D) concentrations, high parathormone (PTH) levels and low bone mineral density (BMD) values. Endogenous synthesis, dietary habits, sunlight exposure and fat-mass-mediated storage may influence 25(OH)D levels and bone metabolism, but the relevance of these factors in the elderly has yet to be fully elucidated. We aimed to investigate the influence of dietary vitamin D intake and fat mass on serum 25(OH)D levels and bone metabolism in older women.

Design

Cross-sectional.

Setting

Community.

Participants

218 fit older women attending a biweekly mild fitness program.

Measurements

Dietary habits was investigated through a 3-day record questionnaire. Serum 25(OH)D and intact parathormone (PTH) concentrations were measured by radioimmunoassay and by a 2-step immunoradiometric assay, respectively. BMD and body composition were estimated using dualenergy X-ray absorptiometry with fan-beam technology.

Results

Only fat mass showed a significant negative association with 25(OH)D (β=-3.76, p<0.001), and positive associations with whole body, lumbar, femoral neck and total hip BMD. Binary logistic analysis revealed a protective effect of adiposity on secondary hyperparathyroidism (OR=0.42, 95%CI:0.19-0.92, p=0.03). Dietary vitamin D intake was not associated to any of these outcomes.

Conclusion

Fat mass has a greater influence on serum 25(OH)D than dietary vitamin D intake.

     

Vitamin D status in young Swedish women with anorexia nervosa during intensive weight gain therapy

Purpose

Anorexia nervosa (AN) is associated with reduced bone mass and an increased fracture risk. The aim was to evaluate the vitamin D status and the association with body mass index (BMI), fat mass and bone mineral density (BMD) in patients with severe AN during a prospective intervention study of intensive nutrition therapy.

Methods

This study comprised 25 Swedish female AN patients (20.1 ± 2.3 years), who were treated as inpatients for 12 weeks with a high-energy diet. Serum 25-hydroxyvitamin D (25(OH)D), calcium, phosphate and parathyroid hormone (PTH) were measured. BMD and body composition were assessed by dual-energy X-ray absorptiometry at study start and after 12 weeks.

Results

Twenty-two patients completed the study. The mean weight gain was 9.9 kg and BMI (mean ± SD) increased from 15.5 ± 0.9 to 19.0 ± 0.9 kg/m², P < 0.0001. Fat mass increased from median 12 to 27 %. The median serum 25(OH)D level was 84 nmol/L at baseline, which decreased to 76 nmol/L, P < 0.05. PTH increased from median 21.9 to 30.0 ng/L, P < 0.0001. BMC increased during the study period, P < 0.001.

Conclusions

Serum 25(OH)D levels were adequate both at study start and completion, however, nominally decreased after the 12-week nutritional intervention. PTH increased subsequently, which coincide with the decreased 25(OH)D levels. The reduction in 25(OH)D could be due to an increased storage of vitamin D related to the increase in fat mass since vitamin D is sequestered in adipose tissue.

     

Evaluation of cognitive subdomains, 25-hydroxyvitamin D,and 1,25-dihydroxyvitamin D in the European Male Ageing Study

Purpose

Although lower levels of vitamin D have been related to poor cognitive functioning and dementia in older adults, evidence from longitudinal investigations is inconsistent. The objective of this study was to determine whether 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)₂D] levels are associated with specified measures of cognitive decline in ageing men.

Methods

The European Male Ageing Study (EMAS) followed 3369 men aged 40–79 over 4.4 years. 25(OH)D levels at baseline were measured by radioimmunoassay, and 1,25(OH)₂D levels were obtained with liquid chromatography–tandem mass spectrometry. Visuoconstructional abilities, visual memory, and processing speed at baseline and follow-up were assessed using the Rey–Osterrieth Complex Figure Test (ROCF), Camden Topographical Recognition Memory (CTRM), and the Digit Symbol Substitution Test (DSST).

Results

Following attritions, a total of 2430 men with a mean (SD) age of 59.0 (10.6) were included in the analyses. At baseline, the mean 25(OH)D concentration was 64.6 (31.5) nmol/l, and mean 1,25(OH)₂D level was 59.6 (16.6) pmol/l. In age-adjusted linear regression models, high 25(OH)D concentrations were associated with a smaller decline in the DSST (β = 0.007, p = 0.020). Men with low 25(OH)D levels (<50 nmol/l) showed a greater decline in the CTRM compared to men with higher (≥75 nmol/l) levels (β = ?0.41, p = 0.035). However, these associations disappeared after adjusting for confounders such as depressive symptoms, BMI, and comorbidities. There was no indication of a relationship between 1,25(OH)₂D and decline in cognitive subdomains.

Conclusion

We found no evidence for an independent association between 25(OH)D or 1,25(OH)₂D levels and visuoconstructional abilities, visual memory, or processing speed over on average 4.4 years in this sample of middle-aged and elderly European men.

     

Season,dietary factors,and physical activity modify 25-hydroxyvitamin D concentration during pregnancy

Purpose

The objectives of this cross-sectional study were to define maternal and umbilical cord blood (UCB) 25-hydroxyvitamin D (25(OH)D) to characterize maternal factors modifying 25(OH)D during pregnancy and predict UCB 25(OH)D in two subgroups with Declined [Δ25(OH)D?<0 nmol/l] and Increased [Δ25(OH)D?>0 nmol/l] 25(OH)D concentration.

Methods

A complete dataset was available from 584 women. 25(OH)D was determined at gestational weeks 6–13 and in UCB. Baseline characteristics were collected retrospectively using questionnaires. Δ25(OH)D was calculated as UCB 25(OH)D?early pregnancy 25(OH)D. Dietary patterns were generated with principal component analysis. Multivariate regression models were applied.

Results

Vitamin D deficiency was scarce, since only 1% had 25(OH)D concentration?<50 nmol/l both in early pregnancy and in UCB. Shared positive predictors of UCB 25(OH)D in the subgroups of Declined and Increased, were early pregnancy 25(OH)D (P?<?0.001) and supplemental vitamin D intake (P?<?0.04). For the Increased subgroup summer season at delivery (P?=?0.001) and “sandwich and dairy” dietary pattern characterized with frequent consumption of vitamin D fortified margarine and milk products (P?=?0.009) were positive predictors of UCB 25(OH)D. Physical activity (P?=?0.041) and maternal education (P?=?0.004) were additional positive predictors in the Declined group

Conclusions

Maternal and newborn vitamin D status was sufficient, thus public health policies in Finland have been successful. The key modifiable maternal determinants for 25(OH)D during pregnancy, and of the newborn, were supplemental vitamin D intake, frequent consumption of vitamin D fortified foods, and physical activity.

     

Evaluation of bone mineral density and 25-hydroxyvitamin D levels in subjects with silica exposure

Objective

The purpose of the study was to evaluate the bone mineral density (BMD) and 25-hydroxyvitamin D (25(OH)D) levels in patients with silica exposure.

Materials and methods

The study included 104 male subjects with silica exposure and 36 healthy subjects. Posterior–anterior radiographs were classified according to the International Labour Office (ILO) Classification. Category 0 patients were classified as Group I (n = 54), category I patients were classified as Group II (n = 25), Category II and III patients were classified as Group III (n = 25).

Results

Femoral neck BMD values were significantly lower in Group III (p = 0.007). Lumbar vertebrae BMD values were significantly lower in all groups with silica exposure than in the control group (p = 0.000). The osteoporosis rate was significantly higher in Group III (p = 0.000). Subjects with silica exposure were determined to have diminished 25(OH)D levels (p = 0.012).

Conclusion

The results of this study demonstrated that subjects with silica exposure have diminished BMD and 25(OH)D levels.

     

Vitamin D supplementation in nursing home residents: Randomized single cholecalciferol loading protocol vs. individualized loading dose regimen

Objective

To assess the efficacy and safety of a single cholecalciferol loading protocol in nursing home (NH) residents taking no VitD supplementation at regular basis.

Design

Randomized single-blind controlled study.

Setting

One NH.

Participants

All residents.

Intervention

From March 21st to May 19th, 2015, NH residents were randomly assigned to either 4x100’000IU to be taken every 2 weeks (treatment group) or an individualized regimen according to baseline 25(OH)VitD level (control group).

Measurements

25(OH) VitD, calcium, phosphorus, parathyroid hormone, alkaline phosphatase, and creatinine serum levels were centrally measured at day 7 after the last dose in both groups, and at baseline in the control group.

Results

111 residents (mean age 85.1±6.7 years) were randomized to the treatment (N=53) or the control group (N=58). No significant difference in terms of demographic characteristics, risk for osteoporosis, and past history of VitD supplementation was measured. At baseline, 37.9%, 25.5% and 5.2% were respectively sub-optimal, insufficient, and deficient for VitD. Whatever the study group, at the 7th day after the last dose of cholecalciferol, 100% of residents reached serum values ≥20ng/mL (p value for non-inferiority <0.001 and p value for superiority p=1.00) and 93.6 vs. 88.2% reached values ≥30ng/mL in the treatment and control group respectively (p value for non-inferiority <0.01 and p value for superiority p=0.48). While mean value was higher in the treatment group (50.2±15.4 vs. 35.8±6.5ng/mL; p <0.0001), none of participants have seen their value >150 ng/mL. Not any biological adverse effects was measured.

Conclusion

This study confirmed that a single loading protocol is at least as effective and safe as tailored regimen in terms of the ability to rapidly normalize 25(OH)VitD values. The often required dosage of 25(OH)VitD is reasonably not necessary to initiate VitD supplementation protocol in this vulnerable population.

     

Vitamin D deficiency was common in all patients at a Swedish primary care centre,but more so in patients born outside of Europe

Background

Vitamin D is associated with extra-skeletal processes, and vitamin D deficiency might contribute to the development of chronic diseases.

Aim

To investigate vitamin D levels in an unselected patient population at a Swedish suburban primary care centre.

Methods

Vitamin D levels were assessed in 102 patients aged 20 to 65 years visiting the primary care centre, independent of cause of visit, during 2 weeks in January 2014. The difference in vitamin D levels between patients born in Europe and patients born outside Europe was calculated using linear regression, adjusting for gender and age. The difference in prevalence of vitamin D deficiency (< 25 nmol/l) was calculated using logistic regression adjusting for gender, age, vitamin D supplement, and sun exposure.

Results

Patients born outside Europe (n?=?66) had 15 nmol/l [95% confidence interval (CI) 9.17–20.84] lower levels of vitamin D than patients born in Europe. Vitamin D deficiency was more common in patients born outside Europe (50%) than in patients born in Europe (11%, odds ratio 8.20 95% CI 2.49–26.98, p?<?0.001).

Conclusion

Lower levels of vitamin D and the prevalence of vitamin D deficiency were more common in patients born outside Europe compared to patients born in Europe.

     

A systematic review of vitamin D status in southern European countries

Purpose

Despite an acknowledged dearth of data on serum 25-hydroxyvitamin D (25(OH)D) concentrations from Southern European countries, inter-country comparison is hampered by inconsistent data reporting. The purpose of the current study was to conduct a systematic literature review of available data on serum 25(OH)D concentrations and estimate vitamin D status in Southern European and Eastern Mediterranean countries, both at a population level and within key population subgroups, stratified by age, sex, season and country.

Methods

A systematic review of the literature was conducted to identify and retrieve scientific articles reporting data on serum 25(OH)D concentration and/or vitamin D status following standard procedures.

Results

Data were extracted from 107 studies, stratified by sex and age group, representing 630,093 individuals. More than one-third of the studies reported mean 25(OH)D concentrations below 50 nmol/L and ~?10% reported mean serum 25(OH)D concentrations below 25 nmol/L. Overall, females, neonates/ infants and adolescents had the higher prevalence of poor vitamin D status. As expected, there was considerable variability between studies. Specifically, mean 25(OH)D ranged from 6.0 (in Italian centenarians) to 158 nmol/L (in elderly Turkish men); the prevalence of serum 25(OH)D?<?50 nmol/L ranged from 6.8 to 97.9% (in Italian neonates).

Conclusions

Contrary to expectations, there was a high prevalence of low vitamin D status in the Southern Europe and the Eastern Mediterranean regions, despite abundant sunshine. These data further emphasize the need for strategies, such as fortification of foods with vitamin D and/or vitamin D supplementation, which will be tailored to the needs of specific population groups with higher risk of insufficiency or deficiency, to efficiently tackle the pandemic of hypovitaminosis D in Europe.

     

High prevalence of vitamin D deficiency among children aged 1 month to 16 years in Hangzhou,China

Background

Recent studies have suggested that vitamin D deficiency in children is widespread. But the vitamin D status of Chinese children is seldom investigated. The objective of the present study was to survey the serum levels of 25-hydroxyvitamin D [25(OH)D] in more than 6,000 children aged 1 month to 16 years in Hangzhou (latitude: 30°N), the capital of Zhejiang Province, southeast China.

Methods

The children aged 1 month to 16 years who came to the child health care department of our hospital, the children's hospital affiliated to Zhejiang university school of medicine, for health examination were taken blood for 25(OH) D measurement. Serum 25(OH) D levels were determined by direct enzyme-linked immunosorbent assay and categorized as < 25, < 50, and < 75 nmol/L.

Results

A total of 6,008 children aged 1 month to 16 years participated in this cross-sectional study. All the subjects were divided into subgroups according to their age: 0-1y, 2-5y, 6-11y and 12-16y representing infancy, preschool, school age and adolescence stages respectively. The highest mean level of serum 25(OH)D was found in the 0-1y stage (99 nmol/L) and the lowest one was found in 12-16y stage (52 nmol/L). Accordingly, the prevalence of serum 25(OH)D levels of < 75 nmol/L and < 50 nmol/L were at the lowest among infants (33.6% and 5.4% respectively) and rose to the highest among adolescents (89.6% and 46.4% respectively). The mean levels of serum 25(OH)D and the prevalence of vitamin D deficiency changed according to seasons. In winter and spring, more than 50% of school age children and adolescents had a 25(OH)D level at < 50 nmol/L. If the threshold is changed to < 75 nmol/L, all of the adolescents (100%) had low 25(OH)D levels in winter and 93.7% school age children as well.

Conclusions

The prevalence of vitamin D deficiency and insufficiency among children in Hangzhou Zhejiang province is high, especially among children aged 6-16 years. We suggest that the recommendation for vitamin D supplementation in Chinese children should be extended to adolescence.

     

Is the 25-hydroxy-vitamin D serum concentration a good marker of frailty?

Introduction

The phenotype proposed by Fried and colleagues is a widely used operational definition of frailty defining such state of extreme vulnerability of older persons. Low serum 25-hydroxy-vitamin D (25(OH)D) has been suggested as biomarker of frailty in literature.

Study design

Cross-sectional.

Objectives

To explore the association of 25(OH)D concentrations with the frailty phenotype and its criteria.

Methods

321 subjects referred by their general practitioner to a geriatric frailty clinic were assessed between January 1, 2013 and September 23, 2013. Adjusted logistic regression models were performed between serum concentrations of 25(OH)D and the frailty phenotype (global score as well as its specific criteria). Receivers operating curves were established in order to explore the existence of a possible threshold of vitamin D levels highly predictive of frailty.

Results

Two hundred forty-one (75%) participants had 25(OH)D levels lower than 22 ng/ml. No significant association was reported between 25(OH)D levels and frailty. Among the five criteria of frailty, 25(OH)D was only associated with sedentariness (odds ratio 0.97 [95% confidence interval 0.95-0.99]).

Conclusion

In our sample, no association was found between 25(OH)D levels and phenotype of frailty or the different frailty criterion except for sedentariness.

     

Vitamin D status and prevalent early age-related macular degeneration in African Americans and Caucasians: The Atherosclerosis Risk in Communities (ARIC) Study

Objectives

Vitamin D status has been hypothesized to protect against development of early age-related macular degeneration (AMD) via its anti-inflammatory properties and its possible beneficial influence on blood pressure control. We investigated the association between vitamin D status and prevalent early AMD in a community-based cohort.

Design

This was a cross-sectional study.

Setting

This was a secondary data analysis of already existing data from the Atherosclerosis Risk in Communities Study (ARIC) cohort collected from 1990 to 1995.

Participants

There were 9,734 (7,779 Caucasians, 1,955 African American) ARIC participants (aged 46 to 70 at visit 2 [1990-1992]) with 25(OH)D data available at visit 2, AMD assessment at visit 3 (1993-1995), and complete covariate data.

Measurements

Vitamin D status was assessed with serum 25-hydroxyvitamin D (25(OH)D) concentrations from bloods drawn at visit 2. Prevalent, early AMD (n=511) was assessed at visit 3 (1993-95) with nonmydriatic retinal photographs of one randomly chosen eye. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for early AMD by categories of 25(OH)D in nmol/L (deficient <30, inadequate 30-<50, and two categories of adequate status: 50-<75 and ≥75). Linear trend was estimated using continuous 25(OH)D concentrations. ORs were adjusted for age, race, and smoking status. We further adjusted for hypertension status to examine if vitamin D status influenced early AMD via its effects on blood pressure. Exploratory analyses of effect modification by age, sex, race and high risk genotypes [Y402H complement factor H (CFH) rs1061170 and the A69S age-related maculopathy susceptibility 2 (ARMS2) rs10490924 polymorphisms] were conducted.

Results

The prevalence of early AMD was 5%, and 5% of participants were vitamin D deficient. The adjusted OR (95% CIs) for early AMD among those with adequate (=75 nmol/L) compared to deficient (<30 nmol/L) vitamin D status was 0.94 (0.59-1.50), p-trend=0.86. Further adjustment for hypertension status did not influence results (OR [95% CI]=0.95 [0.59-1.52], p-trend=0.84). Results did not vary significantly by age, race, sex, early AMD subtype (soft drusen or retinal pigment epithelium depigmentation), or ARMS2 genotype. Results did not vary significantly by CFH genotype in African Americans. The p for multiplicative interaction between 25(OH)D and CFH genotype was 0.06 in Caucasians, but OR [95% CIs] for AMD by vitamin D status were similar in each CFH genotype and not statistically significant.

Conclusion

Vitamin D status was not associated with early AMD in this cohort sample.

     

Relation among 25(OH)D,aquatic exercises,and multifunctional fitness on functional performance of elderly women from the community

Objectives

The aim of this study was to investigate if there is a relation among 25(OH)D, aquatic training, and multifunctional fitness on functional performance of elderly woman from the community. Design: Cross-sectional study.

Setting

Community.

Participants

We evaluated elderly women aged ≥ 60 years (67±5 years old). One-hundred eighty were engaged in aquatic training (AT), 119 in multifunctional fitness (MF) for at least one year, and sedentary group (SED) with 162 independent elderly women from the community centers who had not practicing any regular physical exercise at least one year before.

Measurements

Timed up-and-go (TUG), 2-minute step test (2MST), 30-second chair stand (CS), arm curl (AC), functional reach test (FRT), unipedal balance test (UB) with visual control, handgrip right (HR) and handgrip left (HL) portable dynamometer for strength hip flexors (Hip strength) and knee extensors (Knee strength), serum 25(OH)D, intact parathyroid hormone (PTH), and creatinine clearance.

Results

Physical and functional tests showed differences among the three groups (ST; TUG, CS, AC, FR and USB = p <0.001). The PTH and the TUG test correlated inversely with 25(OH)D (r = -0.29 - p <0.001/ r = - 0.16 - p <0.001), also between 25(OH)D and BMI for AT and MF groups respectively (r= -0,15; p=0,04/ r= - 0,19; p=0,036). The AC test showed positive correlation (r = 0, 1 - p <0.001). The age and 25(OH)D were controlled and assumed to be a covariates in the statistical analysis that employed ANCOVA. There was difference on the performance of TUG test (p= 0.049).

Conclusion

TUG performance was associated with age, exercise type and serum levels of 25(OH)D. The 25(OH)D insufficiency was common in elderly women from subtropical areas.

     

Effect of Vitamin D Treatment on Glucose Homeostasis and Metabolism in Lebanese Older Adults: A Randomized Controlled Trial

Background

A low serum 25-hydroxyvitamin D [(25(OH) D)] concentration was shown to correlate with higher fasting blood glucose (FBG) and insulin levels. Since age affect insulin sensitivity and the metabolism, we aimed in this randomized controlled trial to investigate the effect of vitamin D supplementation on glucose homeostasis and index of insulin resistance in elderly subjects living in Beirut, Lebanon.

Methods

Participants (n= 115) deficient in vitamin D were randomly divided into two groups, a group receiving 30,000 IU cholecalciferol/week for a period of 6 months, and a placebo group. The index of insulin resistance HOMA (homeostasis model assessment) was the primary outcome. Glucose homeostasis and metabolic markers were also measured at start of treatment and at 6 months.

Results

Vitamin D supplementation led to significant improvements in blood levels of [25(OH) D] (P< 0.0001), and a significant decreased of HOMA, PTH and FBG concentrations (P< 0.0001) in the intervention group compared to placebo. No significant changes were observed in HbA1c levels for both groups. Total cholesterol and LDL cholesterol concentrations have also decreased significantly in the intervention group (P< 0.0001).

Conclusion

Short-term supplementation with cholecalciferol improved vitamin D status, and markers of insulin resistance in healthy elder population. This trial was registered at ClinicalTrials.gov; Identifier number#:NCT03478475

     

Low serum levels of 25-hydroxyvitamin D are associated with stroke recurrence and poor functional outcomes in patients with ischemic stroke

Objective

To evaluate the association between serum 25(OH) D levels and functional outcome and stroke recurrence events in a 6-month follow-up study in a cohort of patients with an acute ischemic stroke (AIS).

Methods

From March 2014 to August 2015, consecutive first-ever AIS patients admitted to the Department of Emergency of our hospital were identified. Serum 25(OH) D levels were measured at admission. Functional outcome was evaluated at 6-month using the modified Rankin scale (m-Rankin). We used logistic regression models to assess the relationship between 25(OH) levels and risk of recurrent stroke or functional outcome.

Results

We recorded 277 stroke patients. There were significantly negative correlation between levels of 25(OH) D and NHISS (P<0.001), and the infarct volume (P< 0.001). Thirty-one patients (11.9%) had a stroke recurrence, while 82 patients (29.6) were with poor functional outcomes. In multivariate logistic regression analyses, serum 25(OH) D level was an independent marker of poor functional outcome and stroke recurrence [odds ratio (OR) 2.55 (1.38-3.96) and 3.03(1.65–4.12), respectively, P<0.001 for both, adjusted for NHISS, other predictors and vascular risk factors] in patients with AIS.

Conclusion

Our results demonstrate that low 25(OH) D levels are associated with stroke recurrence and support the hypothesis that 25(OH) D may serve as a biomarker of poor functional outcome after stroke.

     

Association of Serum 25(OH) D Levels with Infarct Volumes and Stroke Severity in Acute Ischemic Stroke

Background

The aim of this study is to investigate whether 25-hydroxyvitamin D [25(OH) D] is associated with initial stroke severity and infarct volume, using diffusion-weighted imaging (DWI) in patients with acute ischemic stroke.

Methods

We studied a total of 235 patients who were admitted within 24 hours of acute ischemic stroke onset. Initial stroke severity was assessed using the NIH Stroke Scale (NIHSS) score. Infarct volume was measured using DWI. Multivariable linear and logistic regression analyses were used to test whether 25(OH) D represents an independent predictor of infarct volume and stroke severity (NIHSS score of ≥6).

Results

Among 235 study patients, the median age was 64 years (IQR 56-75 years), and 125 (53.2%) were women. In multivariable models adjusted for other significant risk factors, 25(OH) D levels in the lowest and second interquartiles were associated with an increased risk of a NIHSS≥6 (with highest 25 (OH) D quartile as reference) with odd ratios (OR) 3.02(95% confidence interval [CI]:1.59-6.34) and 5.85(2.90-11.54). The median DWI infarct volumes for the serum 25(OH) D level quartiles (lowest to highest) were 12.35, 6.55, 2.44, and 1.59 ml. The median DWI infarct volume in the lowest serum 25(OH) D level quartile was larger than that in the other 3 quartiles (P<0.001). The median adjusted DWI infarct volume in the lowest serum 25(OH) D level quartile was statistically significantly larger than that in the other 3 quartiles (P<0.01).

Conclusion

In conclusion, reduced serum 25(OH) D levels in acute ischemic stroke are an early predictor of larger volumes of ischemic tissue and worse neurological deficit (assessed by the NIHSS).

     

Dietary influence on calcitropic hormones and adiposity in Caucasian and African American postmenopausal women assessed by structural equation modeling (SEM)

Objectives

To examine differences in hydroxycholecalciferol (25(OH)D) and parathyroid hormone (PTH) concentrations between Caucasian and African American (AA) postmenopausal women, as well as the effects of dietary calcium, protein and vitamin D intakes on 25(OH)D, PTH, and body adiposity using structural equation modeling (SEM).

Design

Population-based prospective cohort study.

Setting

Academic research using the baseline data from two longitudinal studies.

Participants

Included n=113 Caucasian and n=40 African American, postmenopausal women who completed the baseline data collection and met inclusion criteria (dietary calcium intake <900 mg/day and being generally healthy) between 2006 and 2010.

Main Outcome

Dietary intake of calcium and vitamin D, assessed by dietary records, were examined in relation to calcitropic hormones concentrations and adiposity markers. Independent t-tests, confirmatory factor analysis, SEM and multi-group analyses were conducted to examine the aforementioned relationships as well as group differences among hormones, dietary intake, anthropometrics, age and other factors.

Results

Dietary calcium and protein intakes were significantly lower in AA women. Years since menopause were significantly higher in AA compared to Caucasian women. PTH and 25(OH)D levels were significantly lower in AA compared to Caucasian women. Dietary calcium and protein intakes did not influence body adiposity in either group of women. Dietary vitamin D had minimal indirect (via 25(OH)D levels) influence on adiposity.

Conclusion

The study confirmed the positive relationship of 25(OH)D with adiposity markers and both AA and Caucasian women. The study provides a unique example of the use of SEM in nutrition research within a clinical context. This model should be further tested in other populations.

     

The effectiveness of a preventive health program and vitamin D status in improving health-related quality of life of older Canadians

Purpose

To assess the effectiveness of a preventive health program and vitamin D status in improving the health-related quality of life (HRQOL) of older residents of Canada.

Design

We analyzed baseline and follow-up data of 2119 volunteers of a community program that promotes healthy lifestyles and encourages vitamin D supplementation. We examined the program effect on each of the five dimensions of the EQ-5D-5L, HRQOL score, and quality-adjusted life years (QALYs) using multivariable regression methods. We further examined the specific contribution of vitamin D status as quantified by serum 25-hydroxyvitamin D (25(OH)D).

Results

Problems with mobility, usual activities, pain/discomfort, and depression/anxiety were reported less during follow-up compared to baseline. On average, participants’ HRQOL had improved by 0.018 units at 6 months and 0.025 units at 1 year of follow-up. Improvements in vitamin D status were independently associated with improvements in HRQOL and in QALYs. As per 25 nmol/L increase in 25(OH)D, there was a 0.002 increase in HRQOL and a 0.001 increase in QALYs.

Conclusions

This study documents the benefits of a real-world preventive health program to HRQOL. It is the first to reveal that improvements in vitamin D status parallel improvements in HRQOL among healthy community dwellers. The study further suggests that the preventive health program and supplementation with vitamin D are cost-effective interventions.