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PubMed1997

1alpha-hydroxyvitamin D2 partially dissociates between preservation of cancellous bone mass and effects on calcium homeostasis in ovariectomized rats.

Vitamin D metabolites can prevent estrogen depletion-induced bone loss in ovariectomized (OVX) rats. Our aim was to compare the bone-protective effects of 1alpha,25-dihydroxyvitamin D3 (1, 25(OH)2D3), 1alpha,25-dihydroxyvitamin D2 (1,25(OH)2D2), 1alpha-hydroxyvitamin D3 (1alpha(OH)D3), and 1alpha-hydroxyvitamin D2 (1alpha(OH)D2) in OVX rats. 1alpha(OH)D3 and 1alpha(OH)D2 are thought to be activated in the liver to form 1,25(OH)2D3 and 1, 25(OH)2D2, respectively. Forty-four 12-week-old female Fischer-344 rats were either OVX or sham-operated (SHAM). Groups of OVX rats (n = 7 each) received vehicle alone, 1,25(OH)2D3, 1,25(OH)2D2, 1alpha(OH)D3, or 1alpha(OH)D2, starting 2 weeks after surgery. All vitamin D metabolites were administered orally at a dose of 15 ng/day/rat. Urine and blood samples were collected 6, 9, 12, and 16 weeks after surgery. Serum samples were analyzed for total calcium and phosphate. Calcium, phosphate, creatinine, and free collagen cross-links (ELISA) were determined in urine. After tetracycline double labeling, the rats were sacrificed 16 weeks postsurgery, and the proximal tibiae and the first lumbar vertebrae were processed undecalcified for static and dynamic bone histomorphometry. 1,25(OH)2D3 and, to a slightly lesser extent, 1,25(OH)2D2 elevated vertebral cancellous bone mass in OVX rats to a level beyond that observed in SHAM animals, and both compounds increased serum calcium and urinary calcium excretion to similar extents. 1alpha(OH)D3 and 1alpha(OH)D2 resulted in a 64% and 84%, respectively, inhibition of ovariectomy-induced vertebral cancellous bone loss. In the proximal tibial metaphysis, all vitamin D metabolites tested could only partially prevent post-OVX trabecular bone loss, with a tendency for 1alpha(OH)D3 to be the least active compound. The effects of 1alpha(OH)D3 and 1alpha(OH)D2 on calcium homeostasis differed markedly, however. The mean increase in urinary calcium excretion over the whole experiment was fivefold for 1alpha(OH)D3, whereas the corresponding increase for 1alpha(OH)D2 was only twofold. We conclude that, compared with 1alpha(OH)D3, 1alpha(OH)D2 combined at least equal or higher bone-protective activity in OVX rats with distinctly less pronounced effects on calcium homeostasis. This effect was not due to a differential action of the corresponding main activation products, 1,25(OH)2D3 and 1,25(OH)2D2.

Animals↗
PubMed1997

The metabolism of vitamin D3 in response to testosterone.

Sex steroids were suggested as regulators of vitamin D metabolism. While considerable data is available regarding interaction between estradiol and vitamin D, very little is known about interactions between testosterone and vitamin D. A similar gap exists with regard to the involvement of the vitamin D endocrine system in the pathogenesis of the female versus the male osteoporosis syndrome. In the present study we studied the effect of long-term treatment with testosterone on the metabolism of vitamin D in vitamin D3 replete sexually immature male chicks. We were able to show under this treatment, circulating levels of 1,25-dihydroxy vitamin D3 (1,25(OH)2D3) are significantly reduced, but intestine and bone concentrations are significantly increased. The increased concentration of 1,25(OH)2D3 in bone was accompanied by an increase in the ash content of this tissue. The reduction in serum 1,25(OH)2D3 was not dependent on reduced activity of the renal 25-hydroxy vitamin D3 - alpha - hydroxylase. Based on these findings it is proposed that testosterone is involved in the stimulation of the biological response to vitamin D in the classical target-organs, such as intestine and bone, and this observation may provide partial explanation to the pathogenesis of osteoporosis in hypogonadal men.

Animals↗
PubMed1997

Vitamin D receptor genotypes and intestinal calcium absorption in postmenopausal women.

Several studies have shown that bone mass and bone turnover are genetically determined. This genetic component is thought to be mediated in part by polymorphisms at the vitamin D receptor (VDR) locus, even though the underlying molecular mechanisms are still unknown. To evaluate a possible site of differential action of the VDR gene alleles we examined their correlation with intestinal calcium absorption in 120 Caucasian postmenopausal women (aged 61 +/- 0.6 years). VDR gene polymorphisms for Apa I, Bsm I, and Taq I restriction endonucleases were assessed by Southern blotting analysis. The most common genotypes observed in our population were AaBbTt (37%), AABBtt (20%), aabbTT (15%), AabbTT (15%), and AABbTt (9%). Although there was some evidence of 13% higher lumbar BMD values in aabbTT genotype with respect to AABBtt genotype, this difference of approximately 0.1 g/cm2 did not reach statistical significance, possibly because of the limited number of observations. On the contrary, no relationship was found between genotypes and femoral neck BMD values. Intestinal calcium absorption was significantly lower in BB and tt genotypes than, in bb and TT genotypes, respectively, and in AABBtt genotype than in either aabbTT or AaBbTt genotypes (P = 0.0015 ANOVA). No significant differences in intact PTH, alkaline phosphatase, 25OHD3, and 1, 25(OH)2D3 were found among subjects with different VDR genotypes. These results are consistent with a possible role of VDR alleles on intestinal calcium absorption.

Aged↗
PubMed1998

Relationship between disease activity and serum levels of vitamin D metabolites and PTH in rheumatoid arthritis.

In several studies on patients with rheumatoid arthritis, an association of bone loss with a persistently high disease activity has been found. The aim of our study was to investigate the relation between disease activity and serum levels of vitamin D metabolites, parathyroid hormone (PTH), and parameters of bone turnover in patients with rheumatoid arthritis. A total of 96 patients (83 women and 13 men) were divided into three groups according to disease activity measured by serum levels of C-reactive protein (CRP). In the whole group, serum levels of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) (P < 0.001) and PTH (P < 0.05) were negatively correlated to disease activity. The urinary excretion of collagen crosslinks--pyridinoline (Pyd) (P < 0.001) and deoxypyridinoline (Dpd) (P < 0.05)--showed a positive correlation with disease activity. The inverse correlation between serum 1,25(OH)2D3 and disease activity was separately evident in patients with (P < 0.001) and without (P < 0.01) glucocorticoid treatment, in pre- (P < 0.01) and postmenopausal (P < 0.001) women, and in men (P < 0.01). 1,25(OH)2D3 and PTH serum levels were positively correlated to serum bone alkaline phosphatase (ALP) (P < 0.01). The results indicate that high disease activity in patients with rheumatoid arthritis is associated with an alteration in vitamin D metabolism and increased bone resorption. The decrease of 1,25(OH)2D3 levels in these patients may contribute to a negative calcium balance and inhibition of bone formation. Furthermore, low levels of 1,25(OH)2D3 as an endogenous immunomodulator suppressing activated T cells and the proliferation of cells may accelerate the arthritic process in rheumatoid arthritis.

Adolescent↗
PubMed1998

Age-related changes in serum undercarboxylated osteocalcin and its relationships with bone density, bone quality, and hip fracture.

The effect of the degree of carboxylation of osteocalcin (OC) on the properties of bone is unclear. The aim of this study was to relate serum concentrations of total OC (tOC) and undercarboxylated OC (ucOC), measured with a two-site immunoassay, to bone mineral density (BMD) at the femoral neck and ultrasonic transmitted velocity (UTV) at the os calcis in 257 women aged 60-99 years, 22 of whom had sustained a hip fracture. There was an increase in tOC (r = 0.19, P = 0.003) and ucOC (r = 0.20, P = 0.002) with age. No significant difference in tOC or ucOC between subjects with and without hip fracture was found. Serum tOC was negatively correlated with femoral neck BMD (r = -0.23, P = 0.0001) and os calcis UTV (r = -0.29, P = 0.0001) and partial correlations indicated that these relationships were independent of age. Serum ucOC also correlated negatively with os calcis UTV (r = -0.21, P = 0.001) and less strongly with femoral neck BMD (r = -0.13, P = 0.052). After adjusting for age, only the relationship between ucOC and os calcis UTV remained significant (r = -0.16, P = 0.017). It is concluded that in women over 60 years, the increase in tOC reflects an age-related rise in bone remodeling, whereas the increase in ucOC reflects an age-related fall in vitamin K status. The stronger relationship of ucOC with UTV than BMD suggests that the rise in ucOC may perhaps relate more to changes in bone quality than mineral content. Higher serum ucOC concentrations in subjects with a history of hip fracture could not be confirmed.

Age Factors↗
PubMed1999

Calcidiol and PTH levels in women attending an osteoporosis program.

We performed a retrospective study of 237 patients attending a specialty osteoporosis practice. Secondary causes for reduced bone mineral density (BMD) were evaluated in 196 postmenopausal women and 41 premenopausal women; mean age was 56 +/- 13.8 years (mean +/- SD). BMD was measured by dual-energy X-ray absorptiometry (DXA) (QDR 1000W/2000 Hologic). Levels of intact parathyroid hormone (iPTH), calcidiol [25(OH)D], thyroid-stimulating hormone, and 24-hour urinary calcium were measured, and serum and urine protein (SPEP and UPEP) electrophoresis were performed. Overall, 16% of our patients had 25(OH)D levels <15 ng/ml, the lowest acceptable vitamin D level without a concomitant rise in iPTH levels. Among the osteoporotic patients (T score <-2.5 SD), 17% had 25(OH)D levels <15 ng/ml and 7% <10 ng/ml. Among the osteopenic patients (-2.5 < T < -1.0 SD), 11% had 25(OH)D levels <15 ng/ml. Seventeen percent of patients with Z score </=-1.0 SD (low range normal value) had 25(OH)D levels <15 ng/ml. Low 25(OH)D levels were inversely related to high iPTH values (r = 0.30, P < 0.0001). Hypercalciuria was present in 15% of our patients, elevations of PTH levels (>65 pg/ml, upper normal limit of assay) were present in 11.5%, and hyperthyroidism in 4%. A 25(OH)D level of <25 ng/ml in women (n = 86) with no known secondary causes of low BMD was associated with an iPTH level above 49 pg/ml. The measurement of 25(OH)D levels is recommended in the evaluation of secondary causes for reduced BMD. Supplementation with vitamin D appears needed to keep 25(OH)D above 25 ng/ml, the level required to prevent increments in iPTH levels.

Absorptiometry, Photon↗
PubMed1999

Bone density, vitamin D status, and disordered bone remodeling in end-stage chronic liver disease.

Hepatic osteodystrophy occurs in up to 50% of patients with chronic liver disease (CLD). The aim of this study was to determine the relative contribution of increased resorption and decreased formation to hepatic osteodystrophy by measuring biochemical markers. Twenty-seven patients with advanced CLD (14 female, 13 male) were enrolled. Bone mineral density (BMD), measured at the lumbar spine, and femoral neck, were measured by dual energy X-ray absorptiometry (DXA); bone turnover was assessed using biochemical markers of bone formation and resorption. Based on WHO criteria, osteoporosis and osteopenia were present in 41% and 18% of patients, respectively. All three markers of bone resorption (free deoxypyridinoline, pyridinoline, and hydroxyproline) were increased significantly in patients with CLD. There was a less marked change in the markers of bone formation (osteocalcin, procollagen type 1 peptide, and bone alkaline phosphatase), resulting in a negative uncoupling index in 23/27 (85%) of the patients. Only two (7%) patients had biochemical changes consistent with osteomalacia. The results suggest that increased bone resorption is the predominant cause of hepatic osteodystrophy and therapeutic strategies should be designed to suppress bone resorption, especially in preparation for liver transplantation. Bone biomarkers may be useful alternatives to bone biopsy in evaluating hepatic osteodystrophy.

Absorptiometry, Photon↗
PubMed1999

Circulating beta(2) microglobulin in relation to bone metabolism: implications for bone loss with aging.

The aim of this cross-sectional study was to evaluate the relationships between circulating beta(2) microglobulin (beta(2) m) and bone mineral density (BMD), parameters of bone remodeling, vitamin D metabolites, parathyroid hormone (PTH), estradiol levels, and age in a group of 165 clinically healthy or osteoporotic, but otherwise normal untreated women. In this group of women, systemic beta(2) m correlated with BMD (g/cm(2)) levels for total hip and Ward's triangle (r = -0.298, P < 0.0001; and r = -0.299, P < 0.0001, respectively), but only at the borderline level with BMD at the spine (r = -0.145, P = 0.0604). Serum beta(2) microglobulin markedly correlated with age (r = 0.512, P = 0.0001). beta(2) m levels correlated with indices of bone remodeling, as well as with serum creatinine and estradiol levels. However, after stratification of all analyses by age, body mass index, and serum 25OHD(3), 1, 25(OH)(2)D(3), PTH, or estradiol levels (using standard multiple regression and stepwise forward regression models), only 25OHD(3) was found to be an independent predictor of BMD at the hip, including Ward's triangle, as estradiol of BMD at the spine. On the other hand, beta(2) m was not associated with BMD at any of the measured regions. Also, no association was found between serum PTH and BMD values. Therefore, systemic beta(2) m seems to be an indicator of bone remodeling in the course of natural skeletal aging rather than a variable independently predicting bone loss.

Absorptiometry, Photon↗
PubMed2003

Phase 1B study to improve immune responses in head and neck cancer patients using escalating doses of 25-hydroxyvitamin D3.

Patients with head and neck squamous cell carcinoma (HNSCC) have profound immune defects. These defects are associated with a poor prognosis and are mediated, in part, by immune inhibitory CD34(+) progenitor cells, whose numbers are increased in the peripheral blood of HNSCC patients. Immune inhibitory CD34(+) cells are also present within HNSCC tumors. A phase IB clinical trial was conducted with HNSCC patients to determine if treatment with the differentiation-inducer 25-hydroxyvitamin D(3) could diminish CD34(+) cell levels and improve a panel of immune parameters. Here we present the results of treatment with orally administered escalating doses (20, 40, 60 microg) of 25-hydroxyvitamin D(3), with an emphasis on the six patients who received the maximum dosage of 60 microg per day. Peripheral blood was collected at 0, 1, 2, 4, and 6 weeks, and assessed for markers of immune activity. Although no clinical responses were observed, results of this pilot study demonstrated that treatment of HNSCC patients with 25-hydroxyvitamin D(3 )reduces the number of immune suppressive CD34(+) cells, increases HLA-DR expression, increases plasma IL-12 and IFN-gamma levels, and improves T-cell blastogenesis. In contrast, 25-hydroxyvitamin D(3) treatment did not modulate plasma IL-1beta, IL-2, IL-4, IL-6, IL-10, GM-CSF, or TGF-beta levels.

Aged↗
PubMed2006

Hypercalcemia in rheumatoid arthritis: relationship with disease activity and bone metabolism.

To investigate the relationship between ionized calcium and disease activity, parameters of bone metabolism and bone mineral density (BMD) at the lumbar spine (BMD-LS) and the femoral neck (BMD-FN) measured by dual X-ray absorptiometry in rheumatoid arthritis (RA). In 146 patients with RA, the following parameters were investigated: serum levels of ionized calcium, total calcium, vitamin D metabolites 25-hydroxyvitamin D3 (25D3) and 1,25-dihydroxyvitamin D3 (1,25D3), intact parathyroid hormone (iPTH), interleukin-6, osteocalcin, erythrocyte sedimentation rate (ESR) and c-reactive protein (CRP); renal excretion of pyridinolin (PYD)- and desoxypyridinolin (DPD)-crosslinks. A total of 30.1% of the patients were hypercalcemic (ionized calcium >1.30 mmol/l). In comparison with normocalcemic patients, those with hypercalcemia had significantly higher ESR (P<0.01) and CRP values (P<0.05) and significantly lower serum levels of both iPTH (P<0.01) and 1,25D3 (P<0.05) and a significantly lower BMD-LS (P<0.05). The results indicate that a substantial part of RA patients is hypercalcemic. Hypercalcemia is associated with high disease activity and may contribute to suppression of PTH secretion and vitamin D hormone synthesis. High levels of ionized calcium may be a reflection of disease-activity-related systemic bone loss, and could be a predictor of BMD at the lumbar spine in RA.

Absorptiometry, Photon↗
PubMed2003

Dietary P regulates phosphate transporter expression, phosphatase activity, and effluent P partitioning in trout culture.

Phosphate utilization by fish is an important issue because of its critical roles in fish growth and aquatic environmental pollution. High dietary phosphorus (P) levels typically decrease the efficiency of P utilization, thereby increasing the amount of P excreted as metabolic waste in effluents emanating from rainbow trout aquaculture. In mammals, vitamin D3 is a known regulator of P utilization but in fish, its regulatory role is unclear. Moreover, the effects of dietary P and vitamin D3 on expression of enzymatic and transport systems potentially involved in phosphate utilization are little known. We therefore monitored production of effluent P, levels of plasma vitamin D3 metabolites, as well as expression of phosphatases and the sodium phosphate cotransporter (NaPi2) in trout fed semipu diets that varied in dietary P and vitamin D3 levels. Mean soluble P concentrations varied markedly with dietary P but not with vitamin D3, and constituted 40-70% of total effluent P production by trout. Particulate P concentrations accounted for 25-50% of effluent P production, but did not vary with dietary P or vitamin D3. P in settleable wastes accounted for <10% of effluent P. The stronger effect of dietary P on effluent P levels is paralleled by its striking effects on phosphatases and NaPi2. The mRNA abundance of the intestinal and renal sodium phosphate transporters increased in fish fed low dietary P; vitamin D3 had no effect. Low-P diets reduced plasma phosphate concentrations. Intracellular phytase activity increased but brushborder alkaline phosphatase activity decreased in the intestine, pyloric caeca, and gills of trout fed diets containing low dietary P. Vitamin D3 had no effect on enzyme activities. Moreover, plasma concentrations of 25-hydroxyvitamin D3 and of 1,25-dihydroxyvitamin D3 were unaffected by dietary P and vitamin D3 levels. The major regulator of P metabolism, and ultimately of levels of P in the effluent from trout culture, is dietary P.

6-Phytase↗
PubMed2002

Faecal elastase-1 and fat-soluble vitamin profiles in patients with cystic fibrosis in Western Norway.

BACKGROUND: Exocrine pancreatic insufficiency is a major clinical manifestation of cystic fibrosis (CF). Almost nine of ten patients develop signs and symptoms of maldigestion and malabsorption, which often deteriorates nutritional status and therefore worsens the prognosis. Human faecal elastase-1 (FE-1) has shown promising results to assess exocrine pancreatic insufficiency, and this test has been used at Haukeland University Hospital since 1996. AIM OF THE STUDY: To evaluate FE-1 values and fat-soluble vitamin profiles in patients with CF and to correlate exocrine pancreatic function as measured as FE-1 to fat-soluble vitamin profiles. Moreover, we wanted to assess if there are differences between fat-soluble vitamin profiles in patients with impaired versus patent exocrine pancreatic function, and thirdly, if fat-soluble vitamin deficiency at diagnosis is effectively treated by supplementation. METHODS: Consecutive analyses (N = 212) of fat-soluble vitamin profiles and 35 analyses of FE-1 were investigated in 35 patients with CF. In 17 out of 35 patients fat-soluble vitamin profiles were also assessed at diagnosis. Results Mean value of FE-1 for all CF patients was 256.9 microg/g faeces (median 24.1 microg/g faeces). CF patients considered to have maldigestion (N=24) showed a mean value of 19.9 microg/g faeces (median 18.7 microg/g faeces), those without pancreas affection had a mean value of 773.9 microg/g faeces (median 728.9 microg/g faeces, p < 0.01). There was no difference in fat-soluble vitamin profiles among patients with or without exocrine pancreatic insufficiency while on appropriate supplementation. Median value for vitamin E in patients with exocrine pancreatic insufficiency at diagnosis was low (3.6 mg/L). Supplementation of pancreatic enzymes and vitamins normalised profiles in this group at follow-up. There was no significant correlation between exocrine pancreatic function as measured as FE-1 and fat-soluble vitamin profiles, neither in patients with impaired nor in those with patent pancreatic function. CONCLUSIONS: Severe degree of exocrine pancreatic insufficiency is common in patients with cystic fibrosis. There was no correlation of faecal elastase-1 levels to fat-soluble vitamin status. Fat-soluble vitamins (A, D, E) given in appropriate dosages combined with pancreatic enzymes ensured normal profiles in our patients with CF and malabsorption. Officially recommended supplementation of vitamin A and D in Norway during infancy and childhood may explain why so few patients had vitamin deficiencies at diagnosis.

Adolescent↗
PubMed1996

Effect of growth hormone on urine calcium and serum vitamin D metabolites in renal failure.

Growth hormone (GH) causes a modest increase in urine calcium excretion in normal adults, but uremic rats given both GH and calcitriol developed hypercalciuria. Ten short prepubertal children with renal insufficiency treated with recombinant human GH (rhGH) had urine calcium to creatinine (Ca/Cr) ratios and serum vitamin D metabolite concentrations monitored prospectively for up to 24 months. Six were also treated with calcitriol and two with other vitamin D preparations. Mean urine Ca/Cr ratios or mean serum concentrations of 1,25-dihydroxy vitamin D, 24,25-dihydroxy vitamin D, and 25-hydroxy vitamin D did not change significantly during treatment with rhGH. The risk for rhGH-induced hypercalciuria is small in children with renal insufficiency, even when treated concomitantly with a vitamin D preparation.

24,25-Dihydroxyvitamin D 3↗
PubMed1997

Persistent hypercalciuria and elevated 25-hydroxyvitamin D3 in children with infantile hypercalcaemia.

The aim of the study was to characterize abnormalities of calcium-phosphate and vitamin D3 metabolism in children with a past history of "mild" Lightwood-type idiopathic infantile hypercalcaemia. Seventeen seemingly healthy children aged 2-12 years, with long-term idiopathic hypercalcaemic syndrome since infancy were studied. Two reference groups were also included (vitamin D3 intoxication/healthy and Williams groups). Despite a long-term milk-restricted diet and a restricted vitamin D3 intake, urinary calcium excretion in the study group was 0.117 +/- 0.07 mumol/kg per 24 h. Compared with the reference groups (0.047 +/- 0.029 and 0.067 +/- 0.06 mumol/kg per 24 h, P < 0.05), there was significant hypercalciuria in the children with idiopathic hypercalcaemia since infancy. Serum concentrations of 25-hydroxyvitamin D3 in the study group were also elevated compared with the reference groups (57.4 +/- 15.5 vs. 34.6 +/- 9.3 and 22.7 +/- 10.5 ng/ml). 1,25-Dihydroxyvitamin D3 levels were at the upper limit of normal (45.9 +/- 13.1 vs. 35.0 +/- 8.1 and 30.0 +/- 13.7 pg/ml). Non-progressive, clinically silent nephrocalcinosis was visible on ultrasound examinations. The disturbances of vitamin D3 and calcium-phosphate metabolism persistent in the normocalcaemic phase of idiopathic infantile hypercalcaemia may be a primary metabolic defect of the condition. The mechanisms leading to elevation of metabolites of 1,25-dihydroxy- and 25-hydroxyvitamin D3 and the relationship between this and persistent hypercalciuria and nephrocalcinosis need pathophysiological explanation.

Adolescent↗
PubMed2000

Summer/winter differences in the serum 25-hydroxyvitamin D3 and parathyroid hormone levels of Japanese women.

Serum 25-hydroxyvitamin D3 [25(OH)D3] is produced in the skin in response to exposure to ultraviolet radiation, and is a good indicator of vitamin D nutritional status. The aim of this study was to determine summer/winter differences in serum 25(OH)D3 and parathyroid hormone (PTH) in Japanese women and how the summer and winter values are related. The subjects were 122 healthy Japanese women aged 45-81 years (average age: 65.7 years). They were medically examined twice, in September 1997 and February 1999. Serum 25(OH)D3 and intact PTH were determined by high-performance liquid chromatography and a two-site immunoradiometric assay respectively. Lifestyle information was obtained through an interview. The seasonal differences (winter minus summer) in 25(OH)D3 [delta25(OH)D3] and intact PTH concentrations were -18.8 nmol/l (SD 19.2, P<0.0001) and 0.98 pmol/l (SD 1.02, P<0.0001) respectively. The correlation coefficient between summer (x) and winter (y) 25(OH)D3 levels was 0.462 (P<0.0001), with a linearly fitted line of y=0.42x+26.4. This relationship was interpreted as subjects with higher summer 25(OH)D3 values having greater reductions in winter 25(OH)D3 concentrations. There were inter-individual differences in delta25(OH)D3, although the summer and winter 25(OH)D3 concentrations were well-correlated. Since delta25(OH)D3 was not associated with any of the lifestyle factors, seasonal differences in the 25(OH)D3 concentrations of an individual appeared to reflect her ability to produce 25(OH)D3 photochemically in the skin. Sun bathing would be a less effective means of attaining adequate vitamin D nutritional status in a person with a small seasonal difference in 25(OH)D3, i.e., one with a low 25(OH)D3 level.

Aged↗
PubMed2000

Vitamin D in schizophrenia, major depression and alcoholism.

25-Hydroxyvitamin D3, 1,25-dihydroxyvitamin D3, calcium, phosphate and parathyreoidal hormone levels were assessed in 34 patients with schizophrenia (DSM-III-R, 44% female, mean age 38.9 +/- 2.1 years), 30 patients with alcohol addiction (16% female, mean age 48.7 +/- 2.2 years), 25 patients with major depression (56% female, mean age 57.6+/- years) and 31 healthy controls. Only 25-hydroxyvitamin D3 and 1,25-dihydroxvitamin D3 levels were significantly lower in all groups of psychiatric patients than in normal controls, but not phosphate, calcium and parathyreoidal hormone levels. Significant differences in the vitamin D levels could not be found between the three psychiatric groups. These findings do not support the idea that vitamin D is specifically involved in the pathophysiology of depression. The difference in patients as compared to the healthy controls might be related to a different social background resulting in differing habits e.g. of nutrition.

Adult↗