Vitamin D status in the extreme age of life

The aim of the present study was to investigate vitamin D status in the extreme age of life and to assess the ability of elderly people to synthesize vitamin D in skin, in response to artificial ultraviolet irradiation, and to hydroxylate the newly synthesized vitamin in the liver. The authors have determined the serum 25-hydroxyvitamin D concentrations in 43 healthy subjects (17 males and 26 females) aged 84 years or more. The changes induced in 25-OHD serum levels by whole-body artificial ultraviolet irradiation have also been studied in 10 healthy volunteers aged 41-90 years and, as a control, in 8 normal subjects aged 24-40 years. Serum 25-OHD has been determined, after lipid extraction of samples and column chromatography, by competitive protein binding assay using rat serum as the source of binding protein. The mean 25-OHD serum level in the group studied was 5.7 +/- 4.3 ng/ml, much lower than the mean observed in normal subjects aged 20-40 years (21.3 +/- 8.2 ng/ml). Men had higher levels than women. In the age group 84-89 years 25-OHD levels were higher than in subjects aged 90-96. Serum 25-OHD increased remarkably in all our normal subjects in response to artificial ultraviolet irradiation. Age-related differences in 25-OHD response to irradiation were not significant. The results of the present study indicate that vitamin D deficiency is common in the extreme age of life. It is probably a consequence of poor diet and lack of exposure to sunshine rather than of an impairment of cutaneous synthesis or liver hydroxylation of vitamin D.     

Vitamin D deficiency in elderly patients in a general hospital

Serum 25-hydroxyvitamin D (25-OHD) levels were measured in 338 elderly patients admitted to the Geriatric Medicine Departments of a general hospital in Israel in the course of one year. The mean (+/- SD) serum 25-OHD levels were significantly lower (P less than .01) in the elderly patients (13.5 +/- 8.9 ng/mL) than in healthy young controls (24.7 +/- 6.1 ng/mL). One hundred ten patients (35.5%) were either vitamin D deficient (25-OHD less than 5 ng/mL) or had borderline serum levels of 25-OHD (5-9 ng/mL). The mean (+/- SD) serum 25-OHD concentration of patients who were completely mobile before hospitalization was 15.5 +/- 8.8 ng/mL (n = 239). In patients mainly immobilized but able to leave the house occasionally, it was 10.2 +/- 6.3 ng/mL (n = 84) and of bed-ridden patients, it was 5.2 +/- 3.2 ng/mL (n = 15). No correlation was found between serum 25-OHD levels and the patients' age or serum calcium, phosphorus, alkaline phosphatase, and albumin values. Thus, in order to detect vitamin D deficiency in the elderly, it is necessary to measure serum 25-OHD concentration. The results demonstrate that vitamin D deficiency is common among elderly patients even in sunny climates and indicate the need for development of effective programs of prevention and treatment.     

Low Parathyroid Hormone Levels in Bedridden Geriatric Patients with Vitamin D Deficiency

OBJECTIVES: To identify the clinical conditions associated with low parathyroid hormone (PTH) in patients with vitamin D deficiency and to evaluate the stability of the blunted PTH response to vitamin D deficiency over 6 months.
DESIGN: Secondary analysis of a randomized double-blind controlled vitamin D supplementation trial.
SETTING: Four long-term care hospitals in Helsinki, Finland.
PARTICIPANTS: Two hundred eighteen chronically bedridden patients.
MEASUREMENTS: Plasma 25-hydroxyvitamin D (25-OHD), intact PTH, amino-terminal propeptide of type I procollagen (PINP), carboxy-terminal telopeptide of type I collagen (ICTP), activities of daily living (ADLs), and body mass index (BMI) were measured at baseline and at 6 months. Patient records were reviewed for demographic data.
RESULTS: PTH was within reference values (8–73 ng/L) despite low 25-OHD level (<50 nmol/L) in 74.8% (n=163) of patients (mean age 84.5±7.5). Patients in the lowest PTH quartile (<38 ng/L) were characterized by a history of hip fractures (OR=2.9, P =0.01), low BMI (OR=0.9, P =.02), and high ICTP (OR=1.1, P =.03). PTH remained within reference values even after 6 months in 76.2% of the patients with persistent vitamin D deficiency in the placebo group.
CONCLUSION: The absence of secondary hyperparathyroidism seems to be common and persistent in frail chronically bedridden patients with vitamin D deficiency. Attenuated parathyroid function appears to be associated with immobilization that causes accelerated bone resorption. Further studies addressing the possible adverse effects of low PTH are warranted.     

Effect of immobilization on vitamin D status and bone mass in chronically hospitalized disabled stroke patients.

OBJECTIVE: To assess the influence of immobilization upon vitamin D status and bone mass in chronically hospitalized, disabled, elderly patients following stroke. DESIGN: cross-sectional study. SETTING: Department of geriatric neurology in a Japanese hospital. SUBJECTS: 129 chronically hospitalized, disabled, elderly stroke patients and 28 age-matched controls. RESULTS: We observed a deficiency of both 1,25-dihydroxyvitamin D (1,25-[OH]2D; 24.3 pg/ml) and 25-hydroxyvitamin D concentrations (25-OHD; 11.7 ng/ml) in stroke patients compared with controls. A high serum ionized calcium (mean; 2.648 mEq/l) was an independent determinant of the Barthel index (66) and 1,25-[OH]2D. When the patients were categorized into three groups by 25-OHD level (deficient, insufficient and sufficient), there was no difference in the mean 1,25-[OH]2D levels. Parathyroid hormone levels were normal or low and did not correlate with 25-OHD. Serum bone turnover variables and bone mineral density (BMD) of the second metacarpal in patients were significantly decreased compared to control subjects. Independent determinants of BMD included Barthel index, 25-OHD and 1,25-[OH]2D. CONCLUSIONS: 1,25-[OH]2D deficiency in immobilized stroke patients is not caused by substrate (25-OHD) deficiency but by hypercalcaemia. Immobilization-induced hypercalcaemia may inhibit parathyroid hormone secretion and thus 1,25-[OH]2D production, resulting in decreased BMD. Immobilization itself also may be responsible for decreased BMD. Exogenous 1,25-[OH]2D (calcitriol) rather than dietary vitamin D supplementation may be required in disabled elderly stroke patients who have a deficiency of 1,25-[OH]2D in order to prevent hip fractures, which frequently occur in this population.     

Responses of parathyroid hormone to vitamin D supplementation: a systematic review of clinical trials

The beneficial bone effects of vitamin D supplementation have been attributed to suppression of secondary hyperparathyroidism by 25-hydroxyvitamin D (25-OHD) levels at least 50nmol/l. In this systematic review, we have analyzed the results of 52 clinical trials, including 72 intervention groups and 6290 patients, on vitamin D supplementation in order to evaluate the experimental evidence and the effects of age and chronic immobility on responses of parathyroid hormone (PTH). The papers for this systematic review were selected through a search in PubMed and through a review of the reference lists of articles. Negative logarithmic (R(2)=0.318, p<0.001) and linear (R(2)=0.294, p<0.001) correlations were found between 25-OHD and PTH levels, when all pre- and post-trial values were scattered. Negative linear (R(2)=0.385, p<0.001) and logarithmic (R(2)=0.406, p<0.001) correlations were also found between the changes in 25-OHD and PTH levels. Age correlated negatively with changes in PTH (r=-0.476, p<0.001). The vitamin D supplementation of the chronically immobile patients resulted in a smaller decrease in PTH levels (-8.4 vs. -17.4%, p<0.001) despite a larger increase in 25-OHD levels (187.2% vs. 109.8%, p<0.001). According to the multiple regression analysis the changes in PTH were independently predicted by pre-trial PTH, changes in 25-OHD, age and chronic immobility, explaining 53.2% (R(2)=0.532) of the variation. This meta-analysis shows that responses of PTH to vitamin D supplementation are not only determined by the baseline PTH levels and changes in vitamin D status, but also by age and mobility of the patients. Our results also suggest that PTH decreases quite linearly during vitamin D supplementation at any given 25-OHD level. Longitudinal vitamin D supplementation studies on populations with wide range of mobility and age are needed to further elucidate their confounding effects. In determining the sufficient doses of vitamin D supplementation and adequate 25-OHD levels, these confounding effects and the inter-individual variation in responses of PTH to vitamin D supplementation should be taken into account.     

Associations between vitamin D status and pain in older adults: the Invecchiare in Chianti study

OBJECTIVES: To examine cross-sectional associations between vitamin D status and musculoskeletal pain and whether they differ by sex.
DESIGN: Population-based study of persons living in the Chianti geographic area (Tuscany, Italy).
SETTING: Community.
PARTICIPANTS: Nine hundred fifty-eight persons (aged ≥65) selected from city registries of Greve and Bagno a Ripoli.
MEASUREMENTS: Pain was categorized as mild or no pain in the lower extremities and back; moderate to severe back pain, no lower extremity pain; moderate to severe lower extremity pain, no back pain; and moderate to severe lower extremity and back pain (dual region). Vitamin D was measured according to radioimmunoassay, and deficiency was defined as 25-hydroxyvitamin D (25(OH)D) less than 25 nmol/L.
RESULTS: The mean age±standard deviation was 75.1±7.3 for women and 73.9±6.8 for men. Fifty-eight percent of women had at least moderate pain in some location, compared with 27% of men. After adjusting for potential confounders, vitamin D deficiency was not associated with lower extremity pain or dual-region pain, although it was associated with a significantly higher prevalence of at least moderate back pain without lower extremity pain in women (odds ratio=1.96, 95% confidence interval=1.01–3.59) but not in men.
CONCLUSION: Lower concentrations of 25(OH)D are associated with significant back pain in older women but not men. Because vitamin D deficiency and chronic pain are fairly prevalent in older adults, these findings suggest it may be worthwhile to query older adults about their pain and screen older women with significant back pain for vitamin D deficiency.     

Failure of high-dose ergocalciferol to correct vitamin D deficiency in adults with cystic fibrosis

RATIONALE: Treatment guidelines for vitamin D monitoring and supplementation in cystic fibrosis (CF) have recently been developed and published by a consensus committee, but have not been prospectively tested. OBJECTIVES: To use these guidelines to determine the percentage of adults with CF requiring vitamin D repletion therapy and to evaluate the effectiveness of the currently recommended high-dose oral ergocalciferol repletion protocol. METHODS: Prospective study of clinical outcomes after therapy with the recommended vitamin D repletion algorithm. RESULTS: Of 134 adults with CF, 109 (81.3%) were found to have 25-hydroxyvitamin D (25-OHD) levels below the recommended 30 ng/ml. Sixty-six of these adults completed the recommended course of 400,000 IU of oral ergocalciferol over 2 months, and only five (8%) responded with correction of their serum 25-OHD to the goal of 30 ng/ml or greater (mean change, +0.3 ng/ml; from 18.8 to 19.1 ng/ml). In the 33 adults with CF who also completed the recommended second course of 800,000 IU of ergocalciferol over 2 months, none demonstrated correction of their deficiency (mean change, -1.2 ng/ml). CONCLUSION: The results of this study demonstrate that a majority of adults with CF have serum 25-OHD levels below 30 ng/ml, and the currently recommended ergocalciferol repletion regimen often does not fully correct vitamin D deficiency and may need to be revised to include even higher dosing of ergocalciferol. Further work is needed to establish the ideal 25-OHD level for maximizing calcium absorption and bone health in CF.     

Vitamin D deficiency and its correction in children with sickle cell anaemia

Vitamin D deficiency is common in sickle cell anaemia (SCA, HbSS), although its significance and optimal means of correction are unknown. We conducted an audit to assess the clinical significance of 25-hydroxy vitamin D (25-OHD) deficiency in children with SCA and to evaluate two methods of vitamin D supplementation. We audited 25-OHD levels in 81 children with SCA and looked for statistical associations with biochemical, haematological and clinical parameters. In a separate group of regularly transfused children with SCA, we compared changes in 25-OHD blood concentrations following treatment with either high-dose intramuscular ergocalciferol (n?=?15) or 4 days of high-dose oral cholecalciferol (n?=?64). Ninety-one percent of children with SCA had 25-OHD levels <20 μg/L. The 25-OHD levels were negatively correlated with increasing age (P?P?P?相似文献   

Vitamin D status as a determinant of peak bone mass in young Finnish men

Severe vitamin D deficiency causes rickets, but scarce data are available about the extent to which vitamin D status determines the development of the peak bone mass in young adults. Our aim was to evaluate the prevalence of vitamin D deficiency [serum 25-hydroxyvitamin D (25-OHD) less than the lower limit of the reference range of 20-105 nmol/liter] and the relationship between vitamin D status and peak bone mass among young Finnish men. A cross-sectional study of determinants of peak bone mass with data on lifestyle factors collected retrospectively was performed in 220 young men, aged 18.3-20.6 yr. One hundred and seventy men were recruits of the Finnish Army, and 50 were men of similar age who had postponed their military service for reasons not related to health. Bone mineral content, bone mineral density, and scan area were measured in lumbar spine and upper femur by dual energy x-ray absorptiometry. Serum 25-OHD concentrations were followed prospectively for 1 yr. In July 2000, only 0.9% of the men had vitamin D deficiency, but 6 months later, in the winter, the respective percentage was 38.9%. After adjusting for age, height, weight, exercise, smoking, calcium, and alcohol intake, there existed a positive correlation between serum 25-OHD and bone mineral content at lumbar spine (P = 0.057), femoral neck (P = 0.041), trochanter (P = 0.010), and total hip (P = 0.025). The correlation coefficients for the bone mineral densities at the four measurement sites were 0.035, 0.061, 0.056, and 0.068, respectively. No correlation was found to scan area. We conclude that vitamin D deficiency is very common in Finnish young men in the winter, and it may have detrimental effects on the acquisition of maximal peak bone mass. As in Finland vitamin D supplementation to infants is now stopped at the age of 3 yr, it can be asked whether at our latitude it should be continued from that age onward, not for the prevention of rickets, but as prophylaxis for osteoporosis.     

The effect of vitamin D supplementation on vitamin D status and parathyroid function in elderly subjects

Vitamin D deficiency is common in the elderly and may lead to secondary hyperparathyroidism, cortical bone loss, and hip fractures. The effect of vitamin D supplementation for 1 yr was studied in 72 people living in a nursing home and 70 people living in an aged people's home. The subjects were randomized into 3 groups: control, and 400 or 800 IU vitamin D3/day. The initial vitamin D status of each subject was classified as deficient or borderline [serum 25-hydroxyvitamin D (25OHD) less than 30 nmol/L] in 79% and adequate (serum 25OHD greater than or equal to 30 nmol/L) in 21%. Serum 25OHD concentrations increased about 3-fold in both groups receiving vitamin D supplementation. Serum 1,25-dihydroxyvitamin D [1,25-(OH)2D] concentrations increased slightly but significantly, and the increase was inversely related to the initial serum 25OHD concentration. Serum intact PTH-(1-84) concentrations decreased about 15% during supplementation in both nursing home and aged people's home residents, whereas serum osteocalcin significantly decreased in the nursing home residents only. We conclude that a vitamin D3 supplement of 400 IU/day adequately improves vitamin D status in elderly people and increases 1,25-(OH)2D concentrations in those with vitamin D deficiency. Supplementation decreases parathyroid function and may depress bone turnover to some degree.     

Black and white female adolescents lose vitamin D metabolites into urine

BACKGROUND: The black American population has a higher prevalence of salt sensitivity compared with the white American population. Dahl salt-sensitive rats, models of salt-induced hypertension, excrete protein-bound vitamin D metabolites into urine, a process that is accelerated during high salt intake. We tested the hypothesis that urinary vitamin D metabolite content and 25-hydroxyvitamin D (25-OHD) binding activity of black female adolescents would be greater than that of white female adolescents. METHODS: Female adolescents (11-15 years old, 11 black and 10 white) were fed low (1.3 g, 56 mmol/24 hours sodium) and high salt (3.86 g, 168 mmol/24 hours sodium) diets for 3 weeks in a randomized order cross-over study design. RESULTS: White and black adolescents had similar mean urinary vitamin D metabolite content (low salt, black versus white: 50 +/- 10 versus 58 +/- 17 pmol/24 hours; high salt, black versus white: 47 +/- 7 versus 79 +/- 16 pmol/24 hours). Mean urinary 25-OHD binding activities of the black and white adolescents did not significantly differ. Urinary 25-OHD binding activity of 10/11 black adolescents and 7/10 white adolescents was greater at week 3 of high salt intake than at week 3 of low salt intake (r = 0.50, P = 0.002, n = 17). Plasma 24,25-dihydroxyvitamin D concentrations of the white female adolescents were significantly higher than that of the black female adolescents (P < 0.001). CONCLUSION: Urinary loss of vitamin D metabolites may be one cause of low vitamin D status, in addition to low dietary intake and reduced skin synthesis.     

The frequency of vitamin D deficiency in adults with Crohn's disease.

BACKGROUND: Vitamin D deficiency is a putative, pathogenic cofactor in the increase in osteopenia and osteoporosis seen in patients with Crohn's disease. OBJECTIVE: To determine the frequency of low serum 25-hydroxy-vitamin D3 (25-OHD) levels and the associated alterations in bone mineral density in a cohort of adults with Crohn's disease. METHODS: 25-OHD levels were determined in 242 consecutive patients with Crohn's disease seen in two tertiary inflammatory bowel disease referral centres. Bone mineral density was assessed by dual energy x-ray absorptiometry. RESULTS: Nineteen (8%) patients exhibited vitamin D deficiency (25-OHD less than 25 nmol/L) and 52 (22%) patients exhibited vitamin D insufficiency (25-OHD less than 40 nmol/L). Mean T-scores at the lumbar spine, femoral neck, total hip and ultradistal radius in the group with low 25-OHD did not differ from those of the normal 25-OHD group. Serum alkaline phosphatase and parathyroid hormone levels were higher in the low 25-OHD group than in the normal group. Decreased red blood cell (RBC) folate predicted low 25-OHD in male patients, while smoking, RBC folate and serum iron predicted low 25-OHD in female patients. The rate of low 25-OHD deficiency in the winter was significantly higher than that in the summer (11.9% versus 2.8%, respectively). CONCLUSION: Vitamin D-deficient Crohn's disease patients exhibit biochemical evidence of metabolic bone disease, without detectable differences in bone mineral density. Sunlight exposure, nutrition and smoking status were predictors of vitamin D deficiency in this patient cohort.     

Seasonal variation of serum 25 hydroxy D3 in residents of Tehran

BACKGROUND AND AIM: vitamin D is essential for bone health. It has been shown that in many communities serum levels of vitamin D can be subject to seasonal variations but so far no study has been conducted on this variable in natives of Tehran. SUBJECTS AND METHODS: 1172 natives of Tehran, 682 women and 490 men, aged 3-69 yr entered the study. Sampling was performed monthly except during Ramadhan, the holy month of Islamic fasting. Serum 25-hydroxyvitamin D (25-OHD) was measured using protein binding assay and levels below 20 ng/ml were determined as vitamin D deficient. RESULTS: serum 25-OHD concentrations showed monthly variations in both sexes but the magnitude of variations was more pronounced in men. The nadir of serum levels in both sexes were seen in December and February, 12 +/- 13 and 14 +/- 14 ng/ml in women, and 28 +/- 16 and 24 +/- 18 mg/ml in men, respectively with the highest values being seen in October; 29 +/- 29 ng/ml in women and 55 +/- 27 ng/ml in men. During the whole period of study the maximum values for women were either equal or less than the minimum values for men. The values for men during summer and winter (31 +/- 17 and 28 +/- 22 ng/ ml, respectively) were significantly lower than the values for spring and fall (38 +/- 27 and 43 +/- 29 ng/ml respectively). In women there was no significant difference in the values of the first three seasons and only the values pertaining to winter were significantly different from the values of fall. CONCLUSIONS: the absence of expected seasonal variations in women coupled with obvious deficiency of vitamin D can be attributed to patterns of life style and also to the traditional clothing of the women of Tehran. Nationwide strategies to improve the vitamin D status of the community, specially for women and children, are highly recommended.     

Serum vitamin D levels in children with cystic fibrosis

Osteopenia is increasingly recognized in adults with cystic fibrosis (CF), and is potentially related to vitamin D deficiency in both adulthood and childhood. Vitamin D supplements are recommended and prescribed to all pancreatic-insufficient patients. We aimed to ascertain whether vitamin D deficiency in children with CF was prevalent. 25-hydroxyvitamin D (25-OHD) was measured in 290 children attending a specialist pediatric CF clinic for annual assessment. 25-OHD levels were compared with reference values and to other biochemical markers, lung function, and growth. Levels were also analyzed by pancreatic status and by the presence of CF-related liver disease. Median 25-OHD was 65 (range, 9-190) nmol/l. One percent had levels below 15 nmol/l, and 6% had levels less than 25 nmol/l. Levels were lower in adolescents (P < 0.001) and during the "winter" months (P < 0.001). No relationship was found with pancreatic status or liver disease. In conclusion, the majority of children had normal 25-OHD levels. Interpretation is difficult due to a lack of knowledge of optimal levels of 25-OHD required for healthy bone accretion. Lower levels in adolescents may be a precursor to low levels in adulthood, and did not seem to be simply related to poor compliance with supplementation. This may reflect normal physiology.     

Effects of vitamin D supplementation and exercise training on physical performance in Chilean vitamin D deficient elderly subjects

The aim was to assess the effects of resistance training and vitamin D supplementation on physical performance of healthy elderly subjects. Ninety-six subjects, aged 70 years or more with 25 OH vitamin D levels of 16 ng/ml or less, were randomized to a resistance training or control group. Trained and control groups were further randomized to receive in a double blind fashion, vitamin D 400 IU plus 800 mg of calcium per day or calcium alone. Subjects were followed for nine months. Serum 25 OH vitamin D increased from 12.4+/-2.2 to 25.8+/-6.5 ng/ml among subjects supplemented with vitamin D. Trained subjects had significant improvements in quadriceps muscle strength, the short physical performance test and timed up and go. The latter improved more in trained subjects supplemented with vitamin D. At the end of the follow up, gait speed was higher among subjects supplemented with vitamin (whether trained or not) than in non-supplemented subjects (838+/-147 and 768+/-127 m/12 min, respectively, p=0.02). Romberg ratio was lower among supplemented controls than non-supplemented trained subjects (128+/-40% and 144+/-37%, respectively, p=0.05). In conclusion, vitamin D supplementation improved gait speed and body sway, and training improved muscle strength.     

Vitamin D status,determinants and relationship with biochemical profile in women with Type 2 Diabetes Mellitus in Delhi,India

ObjectiveTo determine the burden of vitamin D deficiency and its determinants and to assess the relationship of 25 hydroxycholecalciferol (25-OHD) levels with biochemical parameters linked to health outcomes in women with Type 2 Diabetes Mellitus (T2DM).Material and methodsThis was a hospital based cross-sectional study in the diabetes out-patient department clinic of a major tertiary care hospital in Delhi, India. Adult women with T2DM on treatment for at least 6 months were included in this study. The women who have been given Vitamin D supplementation during the past 6 months were excluded. We assessed Serum 25-OHD, HbA1c, lipid profile and fasting plasma glucose in the patients through standardized laboratory methods.ResultsOne hundred women with T2DM were enrolled of which 22 (22%) had good glycemic control (HbA1c < 7%). Vitamin D deficiency was seen among 77 (77%) and insufficiency among 16 (16%) of the recruited subjects. Younger age group (31–45 years) and illiteracy was significantly associated with vitamin D deficiency (p < 0.05). No association was found between Vitamin D deficiency and HbA1c levels.ConclusionVitamin D deficiency is highly prevalent among women with T2DM. Illiteracy and young age were major determinants of vitamin D deficiency indicating they need special attention and Vitamin D supplementation.     

Effect of vitamin D supplementation versus placebo on essential hypertension in patients with vitamin D deficiency: a double‐blind randomized clinical trial

Findings from randomized trials addressing the effect of vitamin D supplementation and blood pressure are inconsistent and have been the subject of recent debate. This study aimed to assess the effect of vitamin D supplementation on primary hypertension. This double‐blind randomized clinical trial was conducted on patients aged 26‐84 years with essential hypertension from March 2017 to April 2019. Patients with vitamin D insufficiency (serum vitamin D levels 20‐30 ng/ml) or vitamin D deficiency (serum vitamin D levels <20 ng/ml) were enrolled in the study. Patients were randomly assigned to receive vitamin D supplementation or placebo. Systolic and diastolic blood pressure was measured before the intervention and one and two months thereafter. Of 208 patients enrolled, 171 patients remained for analysis. The effect of vitamin D supplementation on systolic blood pressure was statistically significant in the first and second months after the intervention (P=0.004 and P=0.024, respectively). The effect of vitamin D supplementation on diastolic blood pressure was statistically significant in the first month after the intervention (P=0.046), but not in the second month (P=0.885). No evidence of drug side effects was reported in the two groups. The results of this trial are suggestive of the potential benefits of vitamin D supplementation on blood pressure end points. Therefore, the use of vitamin D may be recommended as an adjuvant drug in the treatment of essential hypertension in patients with vitamin D deficiency because it is safe and well‐tolerated by the patients and can significantly reduce the systolic and diastolic blood pressure. Trial registration: Iranian Registry of Clinical Trials registration number: IRCT201703129014N151.     

Low serum levels of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in institutionalized old people: influence of solar exposure and vitamin D supplementation

The vitamin D status was investigated in 94 geriatric patients in a Danish long-stay ward. The influence of mobility and thus possibility of outdoor activity was studied as well as the influence of regular vitamin D intake. Serum levels of 25-hydroxyvitamin D (25-OHD) were significantly reduced in all groups compared with age-matched controls. In 50% of the patients hypocalcaemia and elevated levels of alkaline phosphatase and immunoreactive parathyroid hormone (iPTH) were found in combination with severely reduced serum 25-OHD values (less than 5 ng/ml) indicating the presence of osteomalacia. Supplementation with 400 IU vitamin D daily in the winter months resulted in significantly higher 25-OHD levels and normocalcaemia while slightly elevated levels of alkaline phosphatase and iPTH persisted. The serum concentrations of 25-OHD were highest in the subjects who were not confined to bed. In these patients the biochemical parameters reflecting osteomalacia were normal. Low serum 1,25-dihydroxyvitamin D levels were found in the patients with low 25-OHD while 24,25-dihydroxyvitamin D levels were within the normal range in all groups and correlated with 25-OHD. Daily vitamin D supplementation appears to be indicated for geriatric patients, especially when bedridden, even in countries where the nutritional vitamin D intake is high.     

Influence of dietary vitamin D3 on the circulating concentration of its active metabolites in the chick and rat.

Plasma concentrations of 25-hydroxyvitamin D3 (25-OHD3) and 1 alpha,25-dihydroxyvitamin D3 (1 alpha, 25-(OH)2D3) in growing chicks and weanling rats were measured by a new radioreceptor assay to determine the effects of varying dietary levels of vitamin D3. The plasma concentration of 25-OHD3 fell from 14.1 ng/ml in 1-day-old chicks to undetectable levels after 3 weeks on a rachitogenic diet. Circulating 1 alpha,25-(OH)2D3 hormone also decreased from 8.9 ng/100 ml to undetectable levels at 3 weeks in these chicks. Chicks receiving an optimal supplement of vitamin D3 (1.4 IU/g diet) for three to four weeks had plasma 25-OHD3 and 1 alpha,25-(OH)2D3 levels of 21-35 ng/ml and 5.1-7.5 ng/100 ml, respectively. Nutritional supplementation with a 50-fold excess of vitamin D3 (70 IU/g diet) elicited a substantial increase in plasma 25-OHD3 to 87-130 ng/ml, while plasma 1 alpha,25-(OH)2D3 was not increased. Increasing dietary calcium from 1.4 to 2.8% did not alter the circulating level of vitamin D3 metabolites in chicks fed 1.4 IU of vitamin D3/g diet. Direct measurement of the renal 25-OHD3-1 alpha-hydroxylase in vitro, showed that lowering dietary calcium or exclusion of vitamin D3 stimulated the biosynthesis of 1 alpha,25-(OH)2D3, but raising calcium did not alter the enzyme activity. It is concluded that the circulating concentration of the 1 alpha,25-(OH)2D3 hormone in the chick is unaffected by abnormally high intakes of vitamin D3 or calcium, but the renal production of the hormone increases during vitamin D3 or calcium deprivation. Additional studies in rats fed a diet supplemented with either 2 or 1000 IU of vitamin D3/g verify that the circulating concentration of 25-OHD3 is markedly increased when the dietary intake of vitamin D3 is elevated. Moreover, 1 alpha,25(OH)2D3 is not increased under these conditions, but actually falls significantly when the dietary level of vitamin D3 is raised from 2 to 1000 IU/g. These studies in both the chick and rat indicate that dietary vitamin D3 excess enhances circulating 25-OHD3, probably because the vitamin D3-25-hydroxylase enzyme is not strigently controlled. The fact that the circulating 1 alpha,25-(OH)2D3 is not concomitantly increased may reflect either decreased synthesis or increased utilization of the 1 alpha,25-(OH)2D3 sterol.     

Vitamin D status was associated with sepsis in critically ill children: A PRISMA compliant systematic review and meta-analysis

Background:Sepsis leads to the high mortality in critically ill infants and children. It is still controversial whether vitamin D deficiency was associated with the incidence of sepsis. Thus we designed the systematic review and meta-analysis.Methods:The Ovid Medline, Embase, PubMed, and Cochrane library were systematically searched until April 5, 2020. The 25 hydroxyvitamin D (25-OHD) level was recorded and set 20 ng/mL as cut-off in cohort study to divide the lower and higher 25-OHD group. The odds ratio (OR) and 95% confidence intervals (CIs) were calculated for comparing the impact of vitamin D deficiency on the incidence of sepsis in critically ill children.Results:A total of 27 studies were included with 17 case-control studies and 10 cohort studies. In those case-control studies, the maternal 25-OHD level and neonatal 25-OHD level in sepsis group was significant lower than non-sepsis group (P < .001). The percentage of severe vitamin D deficiency was significant higher in sepsis group comparing to non-sepsis group (odds ratio [OR] = 2.66, 95% CI = 1.13–6.25, P < .001). In those cohort studies, the incidence of sepsis in lower 25-OHD group was 30.4% comparing with 18.2% in higher 25-OHD level group. However, no statistical significant difference in terms of mechanical ventilation rate and 30-day mortality.Conclusion:We demonstrated that critically ill infants and children with sepsis could have a lower 25-OHD level and severe vitamin D deficiency comparing to those without sepsis. Future studies should focus on the association of vitamin D supplement and the occurrence of sepsis in critically ill children.