Vitamin D deficiency is implicated in reduced serum albumin concentrations in patients with end-stage renal disease

Albumin and multiple sclerosis: a prospective study from UK Biobank

Background

Multiple sclerosis (MS) is a chronic inflammatory disease affecting the central nervous system. While previous studies have indicated that albumin, the primary protein in human plasma, may exert influence on the inflammatory process and confer beneficial effects in neurodegenerative disorders, its role in the context of MS has been underexplored. Here, we aimed to explore the link between albumin and the risk of MS.

Methods

Employing data from the UK Biobank, we investigated the association between baseline levels of serum and urine albumin and the risk of MS using Cox proportional hazards regression analysis.

Results

A higher baseline level of serum albumin was associated with a lower risk of incident MS (HR=0.94, 95% CI: 0.91-0.98, P=7.66E-04). Subgroup analysis revealed a more pronounced effect in females, as well as participants with younger ages, less smoking and deficient levels of vitamin D. Conversely, no association was identified between baseline microalbuminuria level and risk of incident MS.

Conclusion

Higher serum albumin level at baseline is linked to a reduced risk of MS. These results contribute to an enhanced understanding of albumin's role in MS, propose the potential use of albumin as a biomarker for MS, and have implications for the design of therapeutic interventions targeting albumin in clinical trials.

Significant Interactions between Adipokines and Vitamin D Combined with the Estimated Glomerular Filtration Rate: A Geriatric Case Study

Vitamin D deficiency is an important issue in the worldwide population, especially in older people. According to the World Health Organization data, in 2030, 1 in 6 people in the world will be 60 years old or older. The main storage site for vitamin D is adipose tissue. Further, 25(OH)D regulates the expression of adipogenic genes and apoptosis of adipocytes and directly influences the secretion of the appetite-regulating hormone-leptin. Thus, we investigated the impact of the serum concentrations of leptin, adiponectin, omentin, ghrelin, visfatin, and biochemical parameters on vitamin D and estimated glomerular filtration rate (eGFR) in geriatric females. Our studies indicate that the leptin, visfatin and ghrelin are linked with vitamin D concentration and the eGFR rate in the geriatric females. (1) Background: Vitamin D deficiency is common in older people, and researchers are looking for a link between vitamin D deficiency and the occurrence of diseases in advanced age. The study aimed to evaluate the association between serum 25(OH)D levels and clinical variables in older females. (2) Methods: We investigated the impact of the serum concentrations of leptin, adiponectin, omentin, ghrelin, visfatin, and biochemical parameters on vitamin D and estimated the glomerular filtration rate (eGFR) in 74 geriatric females. (3) Results: We observed a significantly higher concentration of creatinine and visfatin in the G2 stage (eGFR = 60-89 mL/min./1.73 m²). We performed an additional analysis to exclude the effect of vitamin D supplementation and obtained a significantly higher vitamin D concentration in the G2 stage. We found significantly lower vitamin D concentrations in older people. In addition, in a person with low levels of vitamin D, we observed significantly lower levels of albumin and ghrelin. Older patients (80 to 89 years old) had significantly lower levels of vitamin D, albumin, insulin, HOMA-IR, and ghrelin than younger patients (60 to 69 years old). Spearman's correlations performed to examine the relationship between clinical variables seemed to confirm previous results. According to ROC curve analysis, leptin concentration was the strongest predictor of vitamin D fluctuations (the area under the curve, AUC = 0.685; with 79.5% sensitivity and 51.4% specificity; p = 0.0291). However, visfatin reached the most accurate AUC^ROC = 0.651 with 84.2% sensitivity and 49.1% specificity for predicting effects on eGFR. (4) Conclusions: The results suggest that serum levels of leptin, visfatin, and ghrelin are linked with vitamin D concentration and the eGFR rate in the population of geriatric females.

Longitudinal Analysis of 1α,25-dihidroxyvitamin D3 and Homocysteine Changes in Colorectal Cancer

Simple Summary

Vitamin D₃ and homocysteine level abnormalities are both strongly related to colorectal cancer (CRC) etiology. The aim of this retrospective study was to investigate the longitudinal change in these two parameters and the relationships between the two, in addition with other clinicopathological and laboratory parameters. A swoosh-shaped trend was observed for the change in serum homocysteine levels of all of the CRC patients. The circulating vitamin D₃ level was constant or increased in those patients without metastasis. After an initial increase, the disease-worsening effect of metastases cancelled out all of the positive effects of vitamin D₃ in metastatic patients, even despite its continuous supplementation. Right-sided tumors, male sex, and the pathological values of serum lipids, albumin, total protein, and inflammatory markers were associated with lower vitamin D₃ and higher homocysteine level. Based on our results, we recommend a modified vitamin D₃ supplementation regimen for metastatic CRC, which includes laboratory measurement-based titration.

Abstract

Background: 1α,25-dihydroxycholecalciferol (1,25(OH)₂D₃) and homocysteine are known to play a role in the pathophysiology of colorectal cancer (CRC). In health, the two changes are inversely proportional to each other, but little is known about their combined effect in CRC. Methods: The serum 1,25(OH)₂D₃ and the homocysteine levels of eighty-six CRC patients were measured, who were enrolled into four cohorts based on the presence of metastases (Adj vs. Met) and vitamin D₃ supplementation (ND vs. D). Results: 1,25(OH)₂D₃ was constant (Adj-ND), increased significantly (Adj-D, p = 0.0261), decreased (Met-ND), or returned close to the baseline after an initial increase (Met-D). The longitudinal increase in 1,25(OH)₂D₃ (HR: 0.9130, p = 0.0111) positively affected the overall survival in non-metastatic CRC, however, this effect was cancelled out in those with metastasis (p = 0.0107). The increase in homocysteine negatively affected both the overall (HR: 1.0940, p = 0.0067) and the progression-free survival (HR: 1.0845, p = 0.0073). Lower 1,25(OH)₂D₃ and/or higher homocysteine level was characteristic for patients with higher serum lipids, albumin, total protein, white blood cell and platelet count, male sex, and right-sided tumors. No statistically justifiable connection was found between the target variables. Conclusions: A measurement-based titration of vitamin D₃ supplementation and better management of comorbidities are recommended for CRC.

Vitamin D Supplementation Improves Fasting Insulin Levels and HDL Cholesterol in Infertile Men

CONTEXT

Vitamin D has been linked with glucose and lipid metabolism. Men with impaired gonadal function have a higher risk of metabolic syndrome and mortality, and vitamin D status may be a reversible modulator.

OBJECTIVE

This work aimed to determine the effect of daily vitamin D and calcium supplementation for 150 days on glucose and lipid homeostasis in infertile men.

METHODS

A single-center, double-blinded, randomized clinical trial (NCT01304927) was conducted. A total of 307 infertile men were randomly assigned (1:1) to a single dose of 300 000 IU cholecalciferol followed by 1400 IU cholecalciferol + 500 mg of calcium daily (n = 151) or placebo (n = 156) for 150 days. Reported metabolic parameters including fasting plasma glucose, glycated hemoglobin A1c, fasting serum insulin, homeostatic model assessment of insulin resistance (HOMA-IR), fasting plasma cholesterols, and triglycerides were secondary end points. The primary end point semen quality has previously been reported.

RESULTS

Men receiving vitamin D supplementation improved their vitamin D status, whereas vitamin D status was aggravated in the placebo group characterized by higher serum parathyroid hormone. At the end of the trial, men receiving vitamin D supplementation had 13% lower fasting serum insulin concentrations compared with the placebo-treated group (65 vs 74 pmol/L, P = .018) and 19% lower HOMA-IR (2.2 vs 2.7, P = .025). Moreover, men in the vitamin D group had higher high-density lipoprotein (HDL) cholesterol levels (1.38 vs 1.32 mmol/L, P = .008) compared with the placebo group.

CONCLUSION

High-dose vitamin D supplementation has beneficial effects on glucose homeostasis and HDL cholesterol levels in infertile men.

A Novel Biosensor and Algorithm to Predict Vitamin D Status by Measuring Skin Impedance

The deficiency and excess of vitamin D cause various diseases, necessitating continuous management; but it is not easy to accurately measure the serum vitamin D level in the body using a non-invasive method. The aim of this study is to investigate the correlation between vitamin D levels, body information obtained by an InBody scan, and blood parameters obtained during health checkups, to determine the optimum frequency of vitamin D quantification in the skin and to propose a vitamin D measurement method based on impedance. We assessed body composition, arm impedance, and blood vitamin D concentrations to determine the correlation between each element using multiple machine learning analyses and an algorithm which predicted the concentration of vitamin D in the body using the impedance value developed. Body fat percentage obtained from the InBody device and blood parameters albumin and lactate dehydrogenase correlated with vitamin D level. An impedance measurement frequency of 21.1 Hz was reflected in the blood vitamin D concentration at optimum levels, and a confidence level of about 75% for vitamin D in the body was confirmed. These data demonstrate that the concentration of vitamin D in the body can be predicted using impedance measurement values. This method can be used for predicting and monitoring vitamin D-related diseases and may be incorporated in wearable health measurement devices.

Association between vitamin D metabolites, vitamin D binding protein, and proteinuria in dogs

BACKGROUND

Proteinuria has been associated with progression of renal disease and increased morbidity and mortality in dogs and people. In people, proteinuria also has been associated with hypovitaminosis D. Little is known about the relationship between vitamin D metabolism and proteinuria in dogs.

OBJECTIVES

To further elucidate vitamin D status in dogs with protein-losing nephropathy (PLN) and minimal to no azotemia. We hypothesized that vitamin D metabolites would be lower in dogs with PLN compared to healthy dogs.

ANIMALS

Twenty-three client-owned adult dogs with PLN and 10 healthy control dogs.

METHODS

Serum 25-hydroxyvitamin D (25[OH]D), 1,25-dihydroxyvitamin D (1,25[OH]₂ D), 24,25-dihydroxyvitamin D (24,25[OH]₂ D), serum vitamin D binding protein (VDBP), and urine 25(OH)D concentrations were measured.

RESULTS

Compared to healthy dogs, dogs with PLN had lower concentrations of all vitamin D metabolites (P < .01). Correlations (rho; 95% confidence interval [CI]) in dogs with PLN are reported. Serum 25(OH)D and 24,25(OH)₂ D concentrations were positively correlated with albumin (r = 0.47; 0.07-0.74), and 24,25(OH)₂ D was negatively correlated with urine protein-to-creatinine ratio (UPC; r = -0.54; -0.78 to -0.16). Urine 25(OH)D-to-creatinine ratio was negatively correlated with serum albumin concentration (r = -0.77; -0.91 to -0.50) and positively correlated with UPC (r = 0.79; 0.53-0.91). Serum VDBP concentration was positively correlated with serum albumin concentration (r = 0.53; 0.05-0.81).

CONCLUSIONS AND CLINICAL IMPORTANCE

Dogs with PLN have decreased serum concentrations of vitamin D metabolites. Urine 25(OH)D-to-creatinine ratio and UPC are correlated in PLN dogs. Future studies are needed to assess additional management strategies for dogs with PLN.

25-Hydroxycholecalciferol Concentration Is Associated with Protein Loss and Serum Albumin Level during the Acute Phase of Burn Injury

Background: Burned patients have an increased need for vitamin D supply related to the maintenance of calcium–phosphate homeostasis and the regulation of cell proliferation/differentiation. This study aimed to analyze the concentration of 25-hydroxycholecalciferol and its relationship with severe condition after burn injury. Methods: 126 patients were enrolled in the study. Patients were qualified due to thermal burns—over 10% of total body surface area. On the day of admission, the following parameters were assessed: 25-hydroxycholecalciferol concentration, total protein concentration, albumin concentration, aspartate transaminase activity, alanine transaminase activity, albumin concentration, creatinine concentration, c-reactive protein concentration, procalcitonin concentration, and interleukin-6 concentration. Results: Almost all patients (92%) in the study group had an improper level of vitamin D (<30 ng/mL), with the average of 11.6 ± 10.7 ng/mL; 17.5% of patients had levels of vitamin D below the limit of determination—under 3 ng/mL. The study showed that there are several factors which correlated with vitamin D concentration during the acute phase of burn injury, including: total protein (r = 0.42, p < 0.01), albumin, (r = 0.62, p < 0.01), percentage of body burns (r = 0.36, p < 0.05), aspartate aminotransferase (r = 0.21, p < 0.05), and c-reactive protein (r = 0.22, p < 0.05). We did not find any significant correlation between vitamin D concentration and body mass index. Conclusions: The burn injury has an enormous impact on the metabolism and the risk factors of the deficiency for the general population (BMI) have an effect on burned patients. Our study showed that concentration of 25-hydroxycholecalciferol is strongly correlated with serum albumin level, even more than total burn surface area and burn degrees as expected. We suspect that increased supplementation of vitamin D should be based on albumin level and last until albumin levels are balanced.

Pharmacokinetics of Oral Cholecalciferol in Healthy Subjects with Vitamin D Deficiency: A Randomized Open-Label Study

BACKGROUND

the aim of this study was to investigate the pharmacokinetic (PK) and safety profile of high-dose vitamin D supplementation, comparing different schedules (daily, weekly, or bi-weekly) in an otherwise healthy vitamin D-deficient population. Methods: single-center, open-label study on healthy subjects deficient in vitamin D (25 (OH)D < 20 ng/mL), randomized to receive cholecalciferol (DIBASE^®, Abiogen Pharma, Italy) using three different schedules: Group A: 10,000 IU/day for eight weeks followed by 1000 IU/day for four weeks; Group B: 50,000 IU/week for 12 weeks, Group C: 100,000 IU/every other week for 12 weeks. Total cumulative doses were: 588,000 IU, 600,000 IU, 600,000 IU. The treatment regimens corresponded to the highest doses allowed for cholecalciferol for the correction of vitamin D deficiency in adults in Italy.

RESULTS

mean 25 (OH)D plasma levels significantly increased from baseline 13.5 ± 3.7 ng/mL to peak values of 81.0 ± 15.0 ng/mL in Group A, 63.6 ± 7.9 ng/mL in Group B and 59.4 ± 12 ng/mL in Group C. On day 28, all subjects showed 25 (OH)D levels ≥ 20 ng/mL and 93.1% had 25 (OH)D levels ≥ 30 ng/mL. On day 56 and 84, all subjects had 25 (OH)D levels ≥ 30 ng/mL. No serious adverse events occurred during the study.

CONCLUSIONS

normalization of 25 (OH)D serum levels was quickly attained with all the studied regimens. A more refracted schedule provided a higher systemic 25 (OH)D exposure.

Acute Phase Proteins and Vitamin D Seasonal Variation in End-Stage Renal Disease Patients

End-stage renal disease (ESRD) patients are vulnerable to vitamin D deficiency due to impaired renal hydroxylation, low dietary intake and inadequate sun exposure. Vitamin D plays a role in innate and adaptive immunity and its seasonal variation has been linked to mortality. ESRD is associated with inadequate removal of pro-inflammatory cytokines regulating acute phase protein (APP) synthesis. Our aim was to look for associations between lifestyle factors, diet, and vitamin D seasonal variation and their relationship with selected APPs and calcium-phosphate metabolism. The study included 59 ESRD patients treated with maintenance hemodialysis. A 24-hour dietary recall was conducted in the post-summer (November 2018, PS) and post-winter (February/March 2019, PW) period, and blood was collected for the measurements of serum total vitamin D, α1-acid glycoprotein (AGP), C-reactive protein (CRP), albumin, prealbumin (PRE), parathormone, calcium and phosphate. A self-constructed questionnaire gathered information on vitamin D supplementation, sun exposure and physical activity. Higher caloric intake was observed PW compared PS. Less than 15% of participants met the dietary recommendations for energy, protein, fiber, vitamin D and magnesium intake. Vitamin D supplementation was associated with higher serum vitamin D regardless of season. AGP, PRE, albumin, and vitamin D presented seasonal changes (higher values PS). In patients with serum vitamin D below 25 ng/mL, vitamin D seasonal change correlated with CRP and prealbumin change. Phosphate and Ca × P correlated positively with AGP. A low vitamin D serum level could impact the inflammatory process; however, more studies are needed to confirm the relationship.

Serum Admission 25-Hydroxyvitamin D Levels and Outcomes in Initially Non-Septic Critically Ill Patients

INTRODUCTION

To examine whether very low levels of 25-hydroxyvitamin D {25(OH)D} upon admission to the intensive care unit (ICU) are associated with worse outcomes.

METHODS

Retrospective observational cohort study of critically ill patients treated in a multidisciplinary ICU. Two hundred twenty seven initially non-septic, critically ill patients, in whom 25-hydroxyvitamin D was measured at ICU admission. An additional group of 192 healthy subjects was also used. Patients were categorized according to their vitamin D levels at admission; the two patient groups were those with severely low 25-hydroxyvitamin D levels (<7 ng/mL, N = 101) and those with vitamin D levels ≥7 ng/mL, N = 126.

RESULTS

ICU admission 25-hydroxyvitamin D levels of critically ill patients were much lower than those of healthy subjects (P < 0.0001). The median time to sepsis for the two patient groups did not differ, nor did the length of ICU stay (days). Both groups exhibited similar hospital mortality rates. However, among the fraction of patients who eventually became septic (N = 145), the odds ratio (OR) for developing respiratory infections in patients with admission vitamin levels < 7 ng/mL compared with patients with admission vitamin D levels ≥7 ng/mL was 5.25 {95% confidence interval (CI) 1.5-18.32, P = 0.009}.

CONCLUSIONS

Initially non-septic critically ill patients appear to have very low ICU admission 25-hydroxyvitamin D levels. Among critically ill patients, severely low vitamin D levels (<7 ng/mL) at ICU admission do not predict sepsis development, increased risk of in-hospital mortality, or longer stay in the ICU. However, these severely low admission vitamin D levels in patients who will eventually develop sepsis are associated with development of respiratory tract infections.

Vitamin D and growth hormone in children: a review of the current scientific knowledge

Background

Human growth is a complex mechanism that depends on genetic, environmental, nutritional and hormonal factors. The main hormone involved in growth at each stage of development is growth hormone (GH) and its mediator, insulin-like growth factor 1 (IGF-1). In contrast, vitamin D is involved in the processes of bone growth and mineralization through the regulation of calcium and phosphorus metabolism. Nevertheless, no scientific study has yet elucidated how they interact with one another, especially as a dysfunction in which one influences the other, even if numerous biochemical and clinical studies confirm the presence of a close relationship.

Main body

We reviewed and analyzed the clinical studies that have considered the relationship between vitamin D and the GH/IGF-1 axis in pediatric populations. We found two main areas of interest: the vitamin D deficiency status in patients affected by GH deficit (GHD) and the relationship between serum vitamin D metabolites and IGF-1. Although limited by some bias, from the analysis of the studies presented in the scientific literature, it is possible to hypothesize a greater frequency of hypovitaminosis D in the subjects affected by GHD, a reduced possibility of its correction with only substitution treatment with recombinant growth hormone (rGH) and an improvement of IGF-1 levels after supplementation treatment with vitamin D.

Conclusions

These results could be followed by preventive interventions aimed at reducing the vitamin D deficit in pediatric age. In addition, further research is needed to fully understand how vitamin D and growth are intertwined.

Association between serum levels of bioavailable vitamin D and negative symptoms in first-episode psychosis

Total vitamin D levels had been commonly reported to be lowered in patients with chronic psychotic illnesses in countries from the higher latitudes. However, studies on patients with first episode psychosis (FEP) are limited. In this study we investigated serum concentrations of total and bioavailable vitamin D levels in FEP patients compared to healthy controls and the association between symptom severity and vitamin D components. A total of 31 FEP patients and 31 healthy controls were recruited from Institute of Mental Health, Singapore. FEP patients were identified using Structured Clinical Interview for DSM-IV Axis I disorders (SCID-1) and severity symptoms were assessed using the positive and negative syndrome scale (PANSS). Sera from participants were analyzed for total vitamin D, vitamin D-binding protein (DBP) and bioavailable vitamin D. Linear regressions were performed to examine the associations between serum total and bioavailable vitamin D and the PANSS subscales. Current study noted a significantly lower bioavailable vitamin D was in the FEP group and an association between bioavailable vitamin D and negative symptoms in FEP patients in a population with a consistent supply of sun exposure throughout the year.

Vitamin D deficiency and dyslipidemia in early pregnancy

Background

Vitamin D deficiency is a common nutritional issue and dietary supplementation in the general population, including pregnant women, is generally advised. Appropriately high levels of vitamin D are expected to play a role in containing the glycemic and atherogenic profiles observed in pregnancy. However, the relation between vitamin D status and the lipid metabolic profile in Saudi women, who are known to suffer from chronic vitamin D deficiency and high incidence of obesity and type II DM, during the course of pregnancy is not known.

Methods

In this study, we analyzed the relation between serum vitamin D level and various serum metabolic markers among Saudi women (n = 515) in their first trimester of pregnancy (11.2 ± 3.4 weeks). Coefficients of Pearson correlation and Spearman rank correlation were calculated for Gaussian and non-Gaussian variables, respectively. Serum vitamin D status was defined as (in nmol/L): deficient (<25), insufficient (25–50); sufficient (50–75) and desirable (>75).

Results

Results indicated that vitamin D status was sufficient in only 3.5 % of the study participants and insufficient and deficient in 26.2 % and 68.0 % of participants, respectively. Serum vitamin D values in the overall study population correlated positively with serum levels of total cholesterol (R = 0.172; p < 0.01), triglycerides (R = 0.184; p < 0.01) and corrected calcium (R = 0.141; p < 0.05). In the subgroup of vitamin D deficient subjects (n = 350), log serum vitamin D values correlated with serum triglycerides (R = 0.23; p = 0.002) and cholesterol (R = 0.26; p = 0.001).

Conclusions

The positive correlations between serum vitamin D and the atherogenic factors such as total cholesterol and triglycerides indicate a pro-atherogenic metabolic status in vitamin D deficient expectant mothers. This may represent an adaptation to the high metabolic demands of pregnancy.

Vitamin D deficiency in adolescents

The prevalence of severe vitamin D deficiency (VDD) in adolescents is variable but considerably high in many countries, especially in Middle-east and Southeast Asia. Different factors attribute to this deficiency including lack of sunlight exposure due to cultural dress codes and veiling or due to pigmented skin, and less time spent outdoors, because of hot weather, and lower vitamin D intake. A potent adaptation process significantly modifies the clinical presentation and therefore clinical presentations may be subtle and go unnoticed, thus making true prevalence studies difficult. Adolescents with severe VDD may present with vague manifestations including pain in weight-bearing joints, back, thighs and/or calves, difficulty in walking and/or climbing stairs, or running and muscle cramps. Adaptation includes increased parathormone (PTH) and deceased insulin-like growth factor-I (IGF-I) secretion. PTH enhances the tubular reabsorption of Ca and stimulates the kidneys to produce 1, 25-(OH) 2D3 that increases intestinal calcium absorption and dissolves the mineralized collagen matrix in bone, causing osteopenia and osteoporosis to provide enough Ca to prevent hypocalcaemia. Decreased insulin like growth factor-I (IGF-I) delays bone growth to economize calcium consumption. Radiological changes are not uncommon and include osteoporosis/osteopenia affecting long bones as well as vertebrae and ribs, bone cysts, decalcification of the metaphysis of the long bones and pseudo fractures. In severe cases pathological fractures and deformities may occur. Vitamin D treatment of adolescents with VDD differs considerably in different studies and proved to be effective in treating all clinical, biochemical, and radiological manifestations. Different treatment regiments for VDD have been discussed and presented in this mini-review for practical use. Adequate vitamin D replacement after treating VDD, improving calcium intake (milk and dairy products), encouraging adequate exposure to the sun and possible enrichment of the stable food with vitamin D in areas with high prevalence of VDD are important measures to prevent the harmful consequences of VDD.

Vitamin d status in thalassemia major: an update

The survival of patients with thalassemia major has progressively improved with advances in therapy; however, osteoporosis and cardiac dysfunction remain frequent complications. Adequate circulating levels of vitamin D are essential for optimal skeletal health and reducing fracture risk. Vitamin D deficiency and insufficiency is reported to be high in thalassemic patients in many countries despite the presence of good sunshine and routine prescription of 400-1,000 IU vitamin D per day. The risk of vitamin D deficiency in thalassemia and its relation to bone disease; including osteoporosis, rickets, scoliosis, spinal deformities and fractures as well as to cardiac dysfunction is discussed in this mini-review. Monitoring and maintaining normal serum level of 25-OH vitamin D through oral intake of vitamin D and early correction of VDD by oral or parental use of vitamin D may significantly improve bone mineral accretion and ameliorate cardiac function.

A formula to predict corrected calcium in haemodialysis patients

BACKGROUND

The conventional calcium correction formula (corrected total calcium (mmol/L) = TCa (mmol/L) + 0.02 [40 (g/L) - albumin (g/L)]) is broadly applied for the estimation of serum calcium in haemodialysis (HD) patients, despite the fact that it was not derived or validated in a HD population. A novel formula was derived and validated for corrected serum calcium in HD patients.

METHODS

Total calcium (TCa), ionized calcium (iCa(2+)), magnesium, phosphate, albumin and bicarbonate were collected from 60 HD patients to derive the formula. A validation set of 237 stable HD patients was then examined, and subjects were classified as hyper-, hypo- and normocalcaemic based on the iCa(2+). Agreement of the new formula was calculated with iCa(2+) as the gold standard, using the intraclass correlation coefficient (ICC). This was compared to the agreement between iCa(2+) and the following: uncorrected total serum calcium (TCa), the conventional correction formula, the Orrell formula and the Clase formula.

RESULTS

Using multiple linear regression the following formula was derived: corrected total calcium (mmol/L) = TCa (mmol/L) + 0.01 [30 (g/L) - albumin (g/L)]. The new formula had superior agreement compared to all of the other formulae. There was a statistically significant greater agreement between the new formula and the iCa(2+) as compared to the conventional formula (P < 0.01). However, the new formula did not significantly outperform the Orrell formula, the Clase formula or Total calcium.

CONCLUSIONS

The use of our simple new formula should enable more appropriate decision making compared to the conventional formula in the highly complex HD population.

Linear growth in relation to the circulating concentrations of insulin-like growth factor I, parathyroid hormone, and 25-hydroxy vitamin D in children with nutritional rickets before and after treatment: endocrine adaptation to vitamin D deficiency

The objective of the study was to determine the degree of linear growth retardation of patients with vitamin D deficiency rickets at presentation and the magnitude of catch-up growth in relation to their calcium (Ca) homeostasis and hormones affecting it before and after treatment. This prospective study recorded the anthropometric data and measured the circulating 25-hydroxy vitamin D (25-OH-D), insulin-like growth factor I (IGF-I), parathyroid hormone, Ca, phosphate, and alkaline phosphatase concentrations in 46 infants and children with nutritional (vitamin D deficiency) rickets before and 6 months or more after treatment with one intramuscular injection of vitamin D3 megadose (300000 IU). Forty normal age- and sex-matched children were included as controls for the auxological data. At presentation, patients' mean age = 13.1 +/- 1.1 months, length standard deviation scores (LSDS) = -1.5 +/- 0.2, and body mass index = 16.3 +/- 0.85. They were significantly shorter and had markedly lower growth velocity standard deviation scores (GVSDS) compared with normal controls (LSDS = 0.25 +/- 0.18 and 0.31 +/- 0.22, respectively). Six months after treatment, the LSDS increased significantly in patients to -0.45 +/- 0.13, with a significantly increased GVSDS (2.76 +/- 0.45) and body mass index (16.9 +/- 0.65). They were still shorter but with significantly higher GVSDS compared with normal controls. Serum Ca and phosphate concentrations increased from 2.07 +/- 0.25 and 1.23 +/- 0.24 mmol/L, respectively, before treatment to 2.44 +/- 0.2 and 1.94 +/- 0.2 mmol/L, respectively, after treatment. Serum alkaline phosphatase and parathyroid hormone concentrations decreased from 1183 +/- 219 U/L and 294 +/- 87 pg/mL, respectively, before treatment to 334 +/- 75 U/L and 35.2 +/- 15.2 pg/mL, respectively, after treatment. The 25-OH-D level increased from 4.5 +/- 0.56 ng/mL before treatment to 44.5 +/- 3.7 ng/mL after treatment. Circulating concentrations of IGF-I increased significantly after treatment (52.2 +/- 18.9 ng/mL) vs before treatment (26.6 +/- 12.8 ng/mL). The 25-OH-D concentrations were correlated significantly with the IGF-I levels before and after treatment (r = 0.603 and r = 0.59, respectively; P < .001). The GVSDS after treatment was correlated with the increase of IGF-I and 25-OH-D levels (r = 0.325 and r= 0.314, respectively; P < .01). These data denote that the accelerated linear growth after treatment of nutritional vitamin D deficiency is mediated through activation of the growth hormone/IGF-I system and suggests an important role of vitamin D as a link between the proliferating cartilage cells of the growth plate and growth hormone/IGF-I secretion. Three different sequential stages of vitamin D deficiency can be recognized according to the clinical/radiological, biochemical, and hormonal data of patients at presentation.

Relationship between 1,25-dihydroxycholecalciferol levels and functional outcome after hip fracture in elderly patients

A prospective study was performed in 109 patients with osteoporotic hip fracture to verify the relationship between 1,25-dihydroxycholecalciferol levels at admission and functional recovery in elderly patients with hip fracture. 47.7% of all the patients had 1,25-dihydroxycholecalciferol levels below the reference values of our laboratory. At 1 year of the fracture only 33 patients (30.3%) had recovered the functional level they had before the fracture. In the bivariate analysis, a statistically significant relationship was found between reduced 1,25-dihydroxycholecalciferol levels and a poorer functional recovery 1 year after the fracture was sustained. A multivariate analysis showed a significant relationship between 1,25-dihydroxycholecalciferol levels and absolute dependence of the patient 1 year after the fracture (P = 0.005; OR 6.97: CI- 1.77-27.41).

Trace elements and vitamins in maintenance dialysis patients

Although protein-energy malnutrition occurs commonly in patients with end-stage renal disease undergoing maintenance dialysis treatment, it is not the only form of malnutrition that may exist in these individuals. They may also suffer from deficiencies of micronutrients, particularly trace elements and vitamins. More commonly occurring vitamin deficiencies in maintenance dialysis patients include those for vitamin C (ascorbate), folate, vitamin B6 (pyridoxine), and 1,25-dihydroxycholecalciferol (calcitriol). Among trace elements, deficiencies may occur more commonly for iron, zinc, and possibly selenium, whereas toxicities are more common with aluminum and possibly copper. Evidence suggests that there is an abnormally high prevalence of antioxidant deficiency in maintenance dialysis patients, especially because a low intake of protein and energy may be associated with inadequate ingestion of antioxidant vitamins (ie, vitamins E and C and carotenoids). Thus, some micronutrient deficiencies in maintenance dialysis patients may contribute to the development of atherosclerotic cardiovascular disease. Dietary requirements for vitamins and trace elements in maintenance dialysis patients are reviewed and the recommended daily intakes are discussed.

Protein and energy nutrition among adult patients treated with chronic peritoneal dialysis

Protein-energy malnutrition (PEM) in adult patients treated with chronic peritoneal dialysis (CPD), which is highly prevalent and frequently severe in its manifestation, poses a significant therapeutic dilemma. The causes of PEM include inflammation, low nutrient intake, nutrient losses during dialysis, metabolic acidemia, coexisting illnesses, and possibly the endocrine disorders of uremia. Treatment strategies for PEM in CPD patients include the following: attempt to treat the potentially reversible causes of anorexia, increase nutrient intake (by nutritional counseling, oral food supplements, consideration of appetite stimulants and intraperitonial amino acid solutions), and the correction of metabolic acidosis. Coexisting illnesses engendering PEM should be treated. Experimental evidence suggests that such agents as anabolic steroids, human growth hormone, insulin-like growth factor-I, and L-carnitine may engender positive protein balance in these individuals. Finally, the use of anti-inflammatory agents to improve the nutritional status of malnourished CPD patients remains to be defined. There is a need to carry out clinical trials that examine whether an improvement in the nutritional status of CPD patients is associated with an improvement in their mortality, morbidity and/or quality of life.

Nutritional requirements with aging. Prevention of disease

Early recognition of and intervention for nutritional disorders may help prevent functional disability and mortality in elderly patients. Prevention of nutritional disorders in older adults is often multidimensional and may require multidisciplinary collaboration. Proactive education of the older adult, early recognition of nutritional deficiencies, and rectification of the nutritional disorders are the keys to achieving ideal nutritional status in elders and enabling them to achieve successful aging.

Influence of vitamin D receptor gene polymorphisms on mortality risk in hemodialysis patients

The BsmI polymorphism of the vitamin D receptor (VDR) gene influences mineral metabolism and the course of cancers and infections. The poly-A polymorphism is in linkage disequilibrium with BsmI and could be responsible for clinical associations attributed to BsmI. The objective of this work is to study the influence of VDR polymorphisms on survival of 143 prevalent hemodialysis (HD) patients followed up for 4 years. Chi-square test was used to study the association between survival and these polymorphisms. Cox analysis was performed, adjusting for comorbid conditions in the entire HD population, groups of patients on HD therapy for less than 5 and 3 years before entering 4 years of observation, patients without diabetes, and patients treated with calcitriol. Survival was analyzed by means of Kaplan-Meier according to BsmI genotypes. Results showed a strong influence of the BsmI polymorphism on survival. The bb genotype was overrepresented among survivors (45.7%) compared with nonsurvivors (21.6%), and Cox analysis showed a significant influence of age, diabetes, calcitriol treatment, and BsmI polymorphism in all groups (in the entire population, Exp(B): BB, 3.9; and Bb, 3 with respect to bb), and also of phosphorus in patients without diabetes and calcitriol-treated patients. Survival means by Kaplan-Meier were as follows: BB, 983 days; Bb, 1,152 days; and bb, 1,290 days (log-rank P = 0.01). The BsmI polymorphism influences survival in HD patients, whereas the poly-A and FokI polymorphisms do not.