Threshold Of Vitamin Research Articles

Association Between Vitamin D Level and Clinical Outcomes of Assisted Reproductive Treatment: A Systematic Review and Dose-Response Meta-Analysis.

The investigation about association between vitamin D level and clinical outcomes of assisted reproductive treatment showed various outcomes. This study aimed to review the correlation between vitamin D and outcomes of assisted reproductive treatment. The search was registered on the PROSPERO database (CRD42023458040). PubMed, Embase, Medline, ClinicalTrials.gov, and Cochrane databases were searched up to July 2023. Twenty-three observational studies were selected for meta-analysis. Comparing groups with deficient and 'insufficient + sufficient' vitamin D level, meta-analysis showed positive correlation between clinical pregnancy rate and vitamin D (OR 0.81, 95%CI: 0.70, 0.95, P = 0.0001). Comparing groups with 'deficient + insufficient' and sufficient vitamin D level, meta-analysis showed positive correlation between vitamin D and clinical pregnancy rate (OR 0.71, 95%CI: 0.55, 0.91, P = 0.006), vitamin D and live birth rate (OR 0.69, 95%CI: 0.54, 0.89, P = 0.003). Subgroup analysis did not show the source of high heterogeneity. No correlation was found in biochemical pregnancy rate, ongoing pregnancy rate, miscarriage rate and implantation rate. In dose-response meta-analysis, a nonlinear association was found between vitamin D levels and outcomes when levels are below approximately 24 ng/L. The study shows that vitamin D level is associated with clinical pregnancy rate and live birth rate. Low vitamin D level does not influence biochemical pregnancy rate, ongoing pregnancy rate, miscarriage rate and implantation rate. Furthermore, 24 ng/L may be a possible threshold of vitamin D concentration in assisted reproduction therapy.

Threshold of 25(OH)D and consequently adjusted parathyroid hormone reference intervals: data mining for relationship between vitamin D and parathyroid hormone

PurposeBy recruiting reference population, we aimed to (1): estimate the 25(OH)D threshold that maximally inhibits the PTH, which can be defined as the cutoff value for vitamin D sufficiency; (2) establish the PTH reference interval (RI) in population with sufficient vitamin D.MethodsStudy data were retrieved from LIS (Laboratory Information Management System) under literature suggested criteria, and outliers were excluded using Tukey fence method. Locally weighted regression (LOESS) and segmented regression (SR) were conducted to estimate the threshold of 25(OH)D. Multivariate linear regression was performed to evaluate the associations between PTH concentration and variables including 25(OH)D, gender, age, estimated glomerular filtration rate (EGFR), body mass index (BMI), albumin-adjusted serum calcium (aCa), serum phosphate(P), serum magnesium(Mg), and blood collection season. Z test was adopted to evaluate whether the reference interval should be stratified by determinants such as age and gender.ResultsA total of 64,979 apparently healthy subjects were recruited in this study, with median (Q1, Q3) 25(OH)D of 45.33 (36.15, 57.50) nmol/L and median (Q1, Q3) PTH of 42.19 (34.24, 52.20) ng/L. The segmented regression determined the 25(OH)D threshold of 55 nmol/L above which PTH would somewhat plateau and of 22 nmol/L below which PTH would rise steeply. Multivariate linear regression suggested that gender, EGFR, and BMI were independently associated with PTH concentrations. The PTH RI was calculated as 22.17–72.72 ng/L for subjects with 25(OH)D ≥ 55 nmol/L with no necessity of stratification according to gender, age, menopausal status nor season.ConclusionThis study reported 25(OH)D thresholds of vitamin D sufficiency at 55 nmol/L and vitamin D deficiency at 22 nmol/L, and consequently established PTH RIs in subjects with sufficient vitamin D for northern China population for the first time.

Assessment of Vitamin D Status in Slovenian Premenopausal and Postmenopausal Women, Using Total, Free, and Bioavailable 25-Hydroxyvitamin D (25(OH)D).

The objective of our study was to evaluate vitamin D status and its predictors in Slovenian premenopausal and postmenopausal women. A cross-sectional study was carried out between 1 March 2021 and 31 May 2021. A total of 319 healthy women from the Central Slovenian region aged between 44 and 65 were recruited; 176 were included in the final analysis. The vitamin D status was determined by measuring the total 25-Hydroxycholecalciferol (25(OH)D) concentration, vitamin D binding protein (DBP), and albumin and calculating the bioavailable 25(OH)D and free 25(OH)D. For the calculation of bioavailable and free 25(OH)D, we developed a new online calculator. The Endocrine Society's thresholds for vitamin D deficiency and insufficiency were used; 29.0% of premenopausal and 24.4% of postmenopausal subjects were found to be vitamin D deficient (total 25(OH)D < 50 nmol/L); 76.8% of the premenopausal and 61.7% of postmenopausal subjects were found to have insufficient levels (total 25(OH)D < 75 nmol/L). Premenopausal women had 11.8% lower total 25(OH)D, 32.2% lower bioavailable 25(OH)D, and 25.2% higher DBP than postmenopausal women. The most important predictors of vitamin D status were vitamin D supplementation and time spent in the sun. Contrary to similar studies, the vitamin D status in Slovenian postmenopausal women was significantly better than in premenopausal women. In postmenopausal women, the measurement of free or bioavailable 25(OH)D instead of the total 25(OH)D could be advantageous.

Vitamin D and musculoskeletal health: outstanding aspects to be considered in the light of current evidence.

Vitamin D enhances calcium absorption and bone mineralisation, promotes maintenance of muscle function, and is crucial for musculoskeletal health. Low vitamin D status triggers secondary hyperparathyroidism, increases bone loss, and leads to muscle weakness. The primary physiologic function of vitamin D and its metabolites is maintaining calcium homeostasis for metabolic functioning, signal transduction, and neuromuscular activity. A considerable amount of human evidence supports the well-recognised contribution of adequate serum 25-hydroxyvitamin D concentrations for bone homeostasis maintenance and prevention and treatment strategies for osteoporosis when combined with adequate calcium intake. This paper aimed to review the literature published, mainly in the last 20 years, on the effect of vitamin D and its supplementation for musculoskeletal health in order to identify the aspects that remain unclear or controversial and therefore require further investigation and debate. There is a clear need for consistent data to establish realistic and meaningful recommendations of vitamin D status that consider different population groups and locations. Moreover, there is still a lack of consensus on thresholds for vitamin D deficiency and optimal status as well as toxicity, optimal intake of vitamin D, vitamin D supplement alone as a strategy to prevent fractures and falls, recommended sun exposure at different latitudes and for different skin pigmentations, and the extra skeletal effects of vitamin D.

Calcifediol (25OH Vitamin D3) Deficiency: A Risk Factor from Early to Old Age.

Vitamin D deficiency is the main cause of nutritional rickets in children and osteomalacia in adults. There is consensus that nutritional access to vitamin D can be estimated by measuring serum concentrations of 25OHD and vitamin D deficiency can thus be considered as calcifediol deficiency. However, the threshold for vitamin D/calcifediol sufficiency remains a matter of debate. Vitamin D/calcifediol deficiency has been associated with musculoskeletal effects but also multiple adverse extra-skeletal consequences. If these consequences improve or if they can be treated with vitamin D supplementation is still unclear. Observational studies suggest a higher infection risk in people with low calcifediol levels. There is also a consistent association between serum calcifediol and cardiovascular events and deaths, but large-scale, long-term intervention studies did not show any benefit on cardiovascular outcomes from supplementation, at least not in subjects without clear vitamin D deficiency. Cancer risk also did not change with vitamin D treatment, although there are some data that higher serum calcifediol is associated with longer survival in cancer patients. In pregnant women, vitamin D supplementation decreases the risk of pre-eclampsia, gestational diabetes mellitus, and low birth weight. Although preclinical studies showed that the vitamin D endocrine system plays a role in certain neural cells as well as brain structure and function, there is no evidence to support a beneficial effect of vitamin D in neurodegenerative diseases. Vitamin D supplementation may marginally affect overall mortality risk especially in elderly subjects with low serum calcifediol concentrations.

The Rational Use of Hormone Replacement Therapy in Older Adults

Multiple hormone levels are lower in older compared to younger adults, but the clinical implications are controversial. Lower thyroid hormone, testosterone, estrogen and vitamin D are variously associated with metabolic syndrome, sarcopenia, low bone density and cognitive decline, for which treatment has been recommended in the past. However, evidence from the T Trials of testosterone therapy failed to show benefit for endpoints other than sexual function. In the Women’s Health Initiative, a large RCT of estrogen replacement in older women, found evidence of an interaction between estrogen therapy and metabolic risk factors such as diabetes that actually exacerbates risk of cognitive decline. Longitudinal observation of thyroid hormone and thyrotropin patterns in the Baltimore Longitudinal Study of Aging demonstrate heterogeneity that might account for a lack of benefit in studies of treatment for subclinical hypothyroidism in older adults. At the same time, new data suggest the need for a more aggressive threshold for vitamin D in older adults, with a lower threshold associated with a drop in physical function compared to younger adults. Complexity in the regulation of hormonal pathways and the downstream effects on target tissues means multiple individuals with similar hormone levels may have different underlying physiology, with divergent clinical needs. Changes in activity and diet common during aging, and exacerbated by the pandemic, lead to physical and mood changes associated with hormonal dysfunction in popular culture and patient requests for evaluation. The ultimate goal should be personalized treatment decisions based on comprehensive evaluation and pathophysiology.

Статус вітаміну D у населення Буковини і Прикарпаття залежно від місця проживання над рівнем моря

Попри певні відмінності у визначенні порогової величини вітаміну D для діагностування його дефіциту у різних країнах, очевидним є факт, що практично в усіх регіонах світу реєструють субоптимальні рівні 25(ОН)D у широких верств населення. При цьому в проведених дослідженнях детально не аналізувався статус вітаміну D залежно від розташування місця проживання над рівнем моря. Мета дослідження: визначити рівень вітаміну D у сироватці крові серед осіб, які проживають у різних регіонах Прикарпаття і Буковини, залежно від розташування населеного пункту над рівнем моря. Матеріал і методи. В одномоментному дослідженні обстежені 353 особи віком від 18 до 86 років, які постійно проживають у різних регіонах Прикарпаття (Коломийський, Косівський, Верховинський райони) і Буковини (Вижницький район). Результати. Лише у 28 випадках (7,9 %) вміст 25(ОН)D у сироватці крові перебував у межах норми, а в інших випадках (92,1 %) спостерігали дефіцит і недостатність вітаміну D. При цьому тяжка форма дефіциту вітаміну D спостерігалася у 7 (1,9 %) обстежених. При порівнянні показників 25(ОН)D у регіонах обстеження було встановлено, що рівень вітаміну D у сироватці був вірогідно вищим у мешканців Верховинського та Косівського районів (розташовані на висоті більше ніж 450 м над рівнем моря) порівняно з жителями Вижниці та Коломиї. Висновок. Середній рівень вітаміну D у сироватці крові дорослої популяції залежить від місця проживання та підвищується зі збільшенням висоти над рівнем моря.

Controversies in Vitamin D: A Statement From the Third International Conference.

The Third International Conference on Controversies in Vitamin D was held in Gubbio, Italy, September 10–13, 2019. The conference was held as a follow‐up to previous meetings held in 2017 and 2018 to address topics of controversy in vitamin D research. The specific topics were selected by the steering committee of the conference and based upon areas that remain controversial from the preceding conferences. Other topics were selected anew that reflect specific topics that have surfaced since the last international conference. Consensus was achieved after formal presentations and open discussions among experts. As will be detailed in this article, consensus was achieved with regard to the following: the importance and prevalence of nutritional rickets, amounts of vitamin D that are typically generated by sun exposure, worldwide prevalence of vitamin D deficiency, the importance of circulating concentrations of 25OHD as the best index of vitamin D stores, definitions and thresholds of vitamin D deficiency, and efficacy of vitamin D analogues in the treatment of psoriasis. Areas of uncertainly and controversy include the following: daily doses of vitamin D needed to maintain a normal level of 25OHD in the general population, recommendations for supplementation in patients with metabolic bone diseases, cutaneous production of vitamin D by UVB exposure, hepatic regulation of 25OHD metabolites, definition of vitamin D excess, vitamin D deficiency in acute illness, vitamin D requirements during reproduction, potential for a broad spectrum of cellular and organ activities under the influence of the vitamin D receptor, and potential links between vitamin D and major human diseases. With specific regard to the latter area, the proceedings of the conference led to recommendations for areas in need of further investigation through appropriately designed intervention trials. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

The relationship between serum 25-hydroxyvitamin D and parathyroid hormone concentration in assessing vitamin D deficiency in pet rabbits

BackgroundVitamin D deficiency and related metabolic bone diseases in pet rabbits have been intermittently debated. In human research, the parathyroid hormone concentration in relation to the 25-hydroxyvitamin D concentration is used to determine vitamin D deficiency. Thus, this study aimed to identify the breakpoint in the 25-hydroxyvitamin D concentration indicating a significant change in the parathyroid hormone concentration in 139 pet rabbits. An enzyme immunoassay kit was used for 25-hydroxyvitamin D analysis and the intact parathyroid hormone (PTH 1–84) immunoradiometric assay kit for parathyroid hormone analysis. The mid-tibial cortical bone density was measured using peripheral quantitative computed tomography. A segmented linear regression analysis was performed, with the 25-hydroxyvitamin D concentration as the independent variable, and parathyroid hormone, ionised calcium, total calcium, inorganic phosphorus concentrations and the mid-tibial cortical density as the dependent variables.ResultsThe breakpoint for the parathyroid hormone concentration occurred at a 25(OH)D concentration of 17 ng/mL, whereas the cortical bone density breakpoint occurred at a 25-hydroxyvitamin D concentration of 19 ng/mL. No breakpoints were found for ionised calcium, total calcium or phosphorus.ConclusionsThese results suggest that a serum 25-hydroxyvitamin D concentration of 17 ng/mL serves as the threshold for vitamin D deficiency in rabbits. Nearly one-third of the rabbits had a serum 25-hydroxyvitamin D concentration below this threshold. Concerns persist regarding the high prevalence of vitamin D deficiency in pet rabbits and the possible health consequences caused by a chronic vitamin D deficiency, including the risk for metabolic bone diseases.

How vitamin D level influences in vitro fertilization outcomes: results of a systematic review and meta-analysis

To investigate the impact of serum vitamin D level on invitro fertilization (IVF) outcomes. Systematic review and meta-analysis. Not applicable. Infertile women undergoing conventional IVF or intracytoplasmic sperm injection (ICSI). Systematic search of PubMed, MEDLINE, EMBASE, Global Health, The Cochrane Library, Health Technology Assessment Database, and Web of Science from inception until July 2019 with cross-checking of references from relevant articles in English. Vitamin D levels were categorized into three groups: deficient (<20 ng/mL), insufficient (20-30 ng/mL), and replete (>30 ng/mL). Before starting the data extraction, we registered the review protocol in PROSPERO (CRD42019134258). We consider clinical pregnancy rate (CPR), live birth rate (LBR), and/or ongoing pregnancy rate (OPR) as primary outcomes. Likewise, the miscarriage rate was considered as a secondary outcome. Primary analysis showed that women with a replete level of vitamin D had higher CPR and LBR/OPR compared to those with a deficient of insufficient level of vitamin D. However, sensitivity analysis led to non-significant differences between the comparators for CPR (odds ratio 0.71, 95% confidence interval 0.47-1.08, I2 = 61%) and OPR/LBR (odds ratio 0.78, 95% confidence interval 0.56-1.08], I2 = 61%). Also, for miscarriage a statistically different rate was not reached. Serum vitamin D levels do not influence IVF outcomes in terms of CPR, LBR/OPR, and miscarriage rate. Future large cohort studies are warranted to determine whether the threshold of vitamin D affects reproductive outcomes. Currently, there is a lack of consensus between the appropriate vitamin D threshold to predict reproductive outcomes compared to the one established for bone health. CRD42019134258.

Nutrihealth Study: Seasonal Variation in Vitamin D Status Among the Slovenian Adult and Elderly Population.

Several studies conducted around the world showed substantial vitamin D insufficiency and deficiency among different population groups. Sources of vitamin D in the human body include ultraviolet B (UVB)-light-induced biosynthesis and dietary intake, but people’s diets are often poor in vitamin D. Furthermore, in many regions, sun exposure and the intensity of UVB irradiation during wintertime are not sufficient for vitamin D biosynthesis. In Slovenia, epidemiological data about vitamin D status in the population were investigated through a national Nutrihealth study—an extension to the national dietary survey SI.Menu (2017/18). The study was conducted on a representative sample of 125 adult (18–64 years) and 155 elderly (65–74 years old) subjects, enrolled in the study in different seasons. Their vitamin D status was determined by measuring the serum 25-hydroxy-vitamin D (25(OH)D) concentration. Thresholds for vitamin D deficiency and insufficiency were 25(OH)D levels below 30 and 50 nmol/L, respectively. Altogether, 24.9% of the adults and 23.5% of the elderly were found to be vitamin D deficient, while an insufficient status was found in 58.2% and 62.9%, respectively. A particularly concerning situation was observed during extended wintertime (November–April); vitamin D deficiency was found in 40.8% and 34.6%, and insufficient serum 25(OH)D levels were observed in 81.6% and 78.8%, respectively. The results of the study showed high seasonal variation in serum 25(OH)D levels in both the adult and elderly population, with deficiency being especially pronounced during wintertime. The prevalence of this deficiency in Slovenia is among the highest in Europe and poses a possible public health risk that needs to be addressed with appropriate recommendations and/or policy interventions.

Screening for hypovitaminosis D: cost-effective or not?

Few topics have elicited more emotion than the issue of screening for vitamin D status and the discussion on the need for global supplementation with vitamin D metabolites. The importance of the problem is highlighted by the USPSTF posted draft research plan with the aim of making an update recommendations statement, possibly next year. Here, we discuss two different viewpoints on screening for vitamin D status: for and against. In the literature there are scientifically sound opinions supporting pro and cons positions. However, we believe that the best way to definitively elucidate this issue is the implementation of a randomized controlled trial evaluating clinical outcomes or harms in persons screened versus those not screened for vitamin D deficiency. The feasibility of such a trial is probably questionable owing to uncertainties still present concerning threshold for vitamin D sufficiency and end points (that is, for example, improved bone mineral density, reduced risk of falls and so on) to be reached.

Vitamin D deficiency in children: a challenging diagnosis!

The concern about the assessment of vitamin D status is growing. Numerous publications warn about the high prevalence of vitamin D deficiency, as well as the potential role of vitamin D in non-bone health outcomes. The status of vitamin D is usually assessed by measuring serum total 25-hydroxyvitamin D (25OHD) concentration. This is the major circulating form of vitamin D and keeps an inverse correlation with serum parathyroid hormone (PTH) concentration. A value of 25OHD of 20 ng/ml is generally assumed as threshold of vitamin D sufficiency in epidemiologic studies because serum PTH tends to increase when the 25OHD concentration stands below this value. In pediatric population, very few studies have analyzed this issue and the negative relationship between serum 25OHD and serum PTH is not clear, which is the suitable circulating concentration of 25OHD and the threshold of deficiency being matters of controversy. The majority of 25OHD circulates in serum tightly bound to a globulin (DBP). According to the free hormone hypothesis, protein-bound hormones are not biologically available and it is the free form that exerts or facilitates the physiologic actions. If this is true, factors that affect DBP may alter the interpretation of total serum 25OHD measurements.

The effect of serum vitamin D levels in couples on embryo development and clinical outcomes.

Do serum vitamin D levels in men and women undergoing IVF/intracytoplasmic sperm injection (ICSI) affect embryo development and clinical outcomes? A large retrospective observational cohort study conducted between March 2016 and March 2017; plasma 25-OHD levels were measured before ovarian stimulation in couples undergoing IVF/ICSI (including 1883 women and 1720 men). Women were divided into four groups in terms of serum 25-OHD quartiles: <14.8ng/ml (Q1), 14.8-19.6ng/ml (Q2), 19.7-24.7ng/ml (Q3) or >24.7ng/ml (Q4). Statistically significant differences in top-quality embryo rates were found among different groups on Day 3 (P = 0.016) but not on Day 2 or Day 5/6. Specifically, the top-quality embryo rate on Day 3 was highest in Q2, a statistically significant difference compared with Q3 (P = 0.014). The multiple linear regression showed that serum 25-OHD levels in women were not significantly related to top-quality embryo rates on Day 2, Day 3 or Day 5/6. There were no differences in implantation, clinical pregnancy, miscarriage and live birth rates among the groups. Logistic regression revealed that there were no significant differences in the success of clinical pregnancy. In men, no significant association was found between vitamin D status and embryo development or clinical outcomes. In neither men nor women were vitamin D levels associated with embryo development in cleavage (Day 2 and Day 3) and blastocyst (Day 5/6) stage and clinical outcomes. This may be because the threshold of vitamin D affecting the reproductive process is relatively low; a multicentre study in a high-latitude region is needed.

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.

Prospective case series. To assess the effectiveness and safety of two vitamin D3 repletion protocols given to individuals with spinal cord injury (SCI). Publicly-funded intensive inpatient rehabilitation center, Montreal, Canada. 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. 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. 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.

Is there a threshold of Vitamin D sufficiency that can prevent secondary hyperparathyroidism?

Is there a threshold of Vitamin D sufficiency that can prevent secondary hyperparathyroidism?

Relationship of circulating levels of 25(OH) vitamin D with parathyroid hormone in Iranian patients with chronic kidney disease not yet on dialysis; what is the best threshold for 25(OH) vitamin D

Introduction: Mineral and bone disorders are common in patients with chronic kidney disease (CKD). Vitamin D plays an important role in calcium-phosphorus balance. Objectives: The main aim of this investigation is to assess the relation between circulating levels of 25(OH) vitamin D and parathyroid hormone (PTH) and estimating the best threshold of vitamin D which may prevent secondary hyperparathyroidism. Patients and Methods: This cross-sectional study was conducted between January 2014 to September 2015. Adult patients with CKD who were not on routine peritoneal dialysis or hemodialysis and did not receive any kidney transplantation, enrolled to this study. Patients who were pregnant or who were on vitamin D supplementation therapy were excluded. Basic demographic and laboratory information were measured. Results: Around 254 patient enrolled in this study (55.1% men). The prevalence of vitamin D deficiency and insufficiency were significantly high, 12.6% and 53.9%, respectively. Serum PTH level increased significantly as circulating plasma level of 25(OH) vitamin D decreased (P = 0.003). Serum total calcium increased significantly with high levels of plasma 25(OH) vitamin D (P < 0.001) and hypercalcemia was seen in 2.8% of patients. Piecewise linear regression modeling of PTH for 25(OH) vitamin D estimated the best threshold for 25(OH) vitamin D of 13.00 ng/mL (95% CI: 2.55-23.44 ng/mL) (P = 0.015). Conclusion: This study again confirms this fact that sufficient level of serum 25(OH) vitamin D is mandatory in patients with CKD in order to prevent secondary hyperparathyroidism. Although this study recommends level of serum 25(OH) vitamin D to be above 13 ng/mL for this purpose.

Vitamin D deficiency related to physical capacity during cardiac rehabilitation

BackgroundVitamin D deficiency is a frequent pathology associated with cardiovascular diseases and physical performance. ObjectiveTo study the link between 25-hydroxyvitamin D (25OHD) level and physical performance and gain in physical performance after cardiovascular rehabilitation (CVR) with vitamin D deficiency. Methods25OHD level was assessed in a retrospective cohort of patients admitted for CVR. Data were collected on physical fitness [6-min walk test distance (6MWD) in percentage of predicted, maximal power (Pmax)]. The threshold of vitamin D deficiency was 20ng/ml chosen according to the literature. ResultsAmong the 131 patients included, as compared with those with nondeficiency (n=83; 63%), patients with vitamin D deficiency (n=48, 37%) had lower initial 6MWD (82±18 vs 89±12% predicted, P=0.009) and Pmax (100±58 vs 120±39W, P=0.006). After CVR, this difference was maintained. The improvement in 6MWD and Pmax was significantly lower with deficiency than nondeficiency, for an increase of 11±8% versus 14±9% predicted (P=0.048) and 10±30 versus 32±30W (P=0.00001), respectively. ConclusionVitamin D deficiency may be associated with impaired physical fitness before CVR and a smaller gain in physical fitness with CVR, probably related to the action of vitamin D on the muscle.

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

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. Cross-sectional. To explore the association of 25(OH)D concentrations with the frailty phenotype and its criteria. 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. 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]). In our sample, no association was found between 25(OH)D levels and phenotype of frailty or the different frailty criterion except for sedentariness.

Association of Vitamin D Level and Subclinical Coronary Artery Disease

Background: The role of vitamin D level in subclinical atherosclerosis remains controversial. We aimed to investigate the relationship between vitamin D level and coronary artery calcium score (CACS). Patients methods: We investigated 303 consecutive patients referred to an outpatient clinic for CACS. The 25-hydroxy vitamin D [25(OH) D] levels were checked within three months of CACS evaluation. Vitamin D levels of <30 and <20 ng/mL were used as thresholds of vitamin D insufficiency and deficiency, respectively. The correlation between CACS and vitamin D was assessed. Unadjusted and covariate-adjusted logistic regression analyses were used to predict positive CACS. Results: The mean age in this study is 61.8 ± 11.8 years (39.9% female). The majority of patients enrolled were Caucasian (87.4%). Median (interquartile range) serum 25(OH) D concentration was 30.0 (23.0, 39.0) ng/ml. Vitamin D was insufficient ( 0) was prevalent in 206 (68%) participants. In the unadjusted model, the 25 (OH) D levels were not associated with the prevalence of CACS among all cases or among patients with positive CACS. Logistic regression models, after controlling for risk factors, did not change the results. In addition, among the 206 participants with prevalent CACS, 25 (OH) D levels were not associated with CACS severity. Conclusions: Our single centre retrospective study in a population with low prevalence of vitamin D deficiency failed to find a significant relation between 25(OH) D level and CACS even when adjusted for risk factors.