Markers Of Calcium Homeostasis Research Articles

Impact of occupational lead exposure on the comprehensive health status of gas cutter workers

BackgroundOccupational exposure to hazardous substances, particularly in involving metal cutting and welding industries, poses critical public health concern. This study assesses the health status of gas cutter workers, focusing on Pb exposure. MethodIn this cross-sectional study, 40 participants with BLL ≥20 μg/dL were recruited from workers engaged in oxy-acetylene metal cutting. These workers were compared to an age-, sex-, and sociodemographic-matched control group (n = 42) from the same workplace. Health assessments including routine clinical and laboratory investigations along with BLL, and markers of calcium homeostasis were carried out. ResultsGas cutters exhibited significantly higher mean systolic BP and elevated SGOT levels, with similar prevalence of respiratory symptoms and musculoskeletal disorders in both groups. No significant differences were found in most hematological, liver, and renal parameters. However, gas cutters had significantly higher PTH levels and lower serum vitamin D levels. Pulmonary function tests indicated significantly reduced FVC, FEV1, FEV1/FVC ratio, FEF25-75 %, and PEFR in gas cutters, as well as markedly higher CRP levels. ConclusionGas cutters experience significant health impacts compared to controls, including elevated systolic BP, impaired pulmonary function, and disturbance in calcium homeostasis due to occupational Pb exposure. Higher CRP levels suggest notable inflammatory responses. These findings highlight the urgent need for targeted interventions and regular monitoring to mitigate health risks associated with Pb exposure among gas cutter workers.

Evaluation of the potential implications of following a vegan diet on bone health

Cow’s milk is the primary source of calcium in the NZ diet(1). The absence of dietary planning in a vegan diet can result in the individual unknowingly obtaining low intakes of calcium. Prolonged low calcium intakes can result in negative implications on bone mineral density by increasing the risk of osteoporosis later in life. The measurement of bone health parameters in NZ vegan adults have not been investigated. Therefore, we measured bone mineral density, markers of calcium homeostasis and assessed intake of essential nutrients for optimal bone health in vegans. This cross-sectional study included adults (>18yrs), who followed a vegan diet for 2 years minimum. Demographic and lifestyle information was obtained from questionnaires including previous history of bone fractures and background of familial osteoporosis. A 4-day food record was completed for analysis of calcium, zinc, protein, magnesium, phosphorus and vitamin C intake and compared to the Estimated Average Requirement (EAR)(2). Weight, height and BMI were obtained, bone mineral density was measured at the hip and spine via dual x-ray absorptiometry (DXA) and reported as Z and T scores. Plasma calcium concentrations were corrected for albumin. All values are presented as mean and standard deviation. The study included 212 participants, aged 39 ± 12.38 years, 71% female. T scores at the lumbar spine and femoral neck were −0.63 ± 1.22 (Z score: −0.29 ± 1.12) and −0.66 ± 1.00 (Z score: −0.24 ± 0.89), respectively. Nine participants had a Z-score of <-2.0 at the lumbar spine, and three at the femoral neck. Corrected calcium concentrations were 2.21 ± 0.33 mmol/L. Calcium intake was 917 ± 347.23 (range 195 to 2,429 mg/day) in all participants, which exceeded the EAR of 840 mg/day for adults aged 19-50 years. Men had higher intakes of calcium than women, 1,051 ± 363.7 mg/day (range 382 to 2,267 mg/day) vs. 867 ± 328.04 mg/day (range 194 to 2,428 mg/day), P-value <0.001. The main source of calcium in the vegan diet was tofu. The intake of protein (77 ± 27.80) g/day, magnesium (569 ± 181.05) mg/day, and vitamin C (145 ± 96.94) mg/day met the EAR, excluding vitamin and mineral supplements. However, the intake of phosphorus (1,472 ± 459.98) mg/day and zinc (10.6 ± 4.01) mg/day were below the EAR. The findings of this study suggest that bone health of vegans are not negatively affected by the exclusion of dairy in the diet, provided that appropriate dietary planning is included to avoid nutrient deficiencies associated with poor bone health. Despite mean intake of calcium exceeding the EAR, very low intakes demonstrated significant variations between participants.

Vitamin D receptor gene polymorphism and serum vitamin D level as risk factors for acquiring Type II diabetes mellitus.

The studies on the relationship between type 2 diabetes mellitus (T2DM) risk and vitamin D receptor (VDR) gene polymorphisms are still inconclusive. Therefore, the objective of the study was to assess possible risks of acquiring T2DM due to polymorphisms in the VDR gene or abnormal serum levels of VD. 362 participants (181 T2DM patients and 181 healthy controls) from the Diabetic Center, Sulaimaniyah/Iraq, from December 2020 to May 2021 were volumtarily enrolled in the study. For each participant, HbA1c, fasting blood sugar (FBS), serum cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglyceride (TG), markers of calcium homeostasis, alkaline phosphatase (ALP), phosphorus, VD and insulin were measured. In addition, FokI, TaqI, ApaI, and BsmI genotypes were also performed using Polymerase Chain Reaction (PCR). The results showed that VD level was significantly lower in T2DM compared to the control group. While, HbA1c was significantly higher in T2DM than in the control group. In contrast to AA (P=0.034) and CC (P=0.011) genotype of ApaI (rs7975232) gene polymorphism, which were dominant among the control group, AC-genotype was significantly (P=0.0001) dominat among T2DM group. Meanwhile, TT-genotype of TaqI (rs731236) was significantly (P=0.05) dominant among control group. While there were not any significant differences between other genotypes among T2DM and control groups. In conclusion, low VD-level is a possible risk factor for developing T2DM, and an association was found, especially betweenApaI genotypes and T2DM.

The Effect of SERCA Activation on Functional Characteristics and Signaling of Rat Soleus Muscle upon 7 Days of Unloading.

Skeletal muscle abnormalities and atrophy during unloading are accompanied by the accumulation of excess calcium in the sarcoplasm. We hypothesized that calcium accumulation may occur, among other mechanisms, due to the inhibition of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) activity. Consequently, the use of the SERCA activator will reduce the level of calcium in the sarcoplasm and prevent the negative consequences of muscle unloading. Wistar rats were randomly assigned into one of three groups (eight rats per group): control rats with placebo (C), 7 days of unloading/hindlimb suspension with placebo (7HS), and 7 days of unloading treated with SERCA activator CDN1163 (7HSC). After seven days of unloading the soleus muscle, the 7HS group displayed increased fatigue in the ex vivo test, a significant increase in the level of calcium-dependent CaMK II phosphorylation and the level of tropomyosin oxidation, as well as a decrease in the content of mitochondrial DNA and protein, slow-type myosin mRNA, and the percentage of slow-type muscle fibers. All of these changes were prevented in the 7HSC group. Moreover, treatment with CDN1163 blocked a decrease in the phosphorylation of p70S6k, an increase in eEF2 phosphorylation, and an increase in MuRF-1 mRNA expression. Nevertheless, there were no differences in the degree of fast and slow muscle fiber atrophy between the 7HS and 7HSC groups. Conclusion: SERCA activation during 7 days of unloading prevented an increase in soleus fatigue, the decrease of slow-type myosin, mitochondrial markers, and markers of calcium homeostasis but had no effect on muscle atrophy.

Down regulation of the inverse relationship between parathyroid hormone and irisin in male vitamin D-sufficient HIV patients.

Infection with the human immunodeficiency virus (HIV) predisposes to endocrine disorders, manifesting as a metabolic phenotype that affects the entire adipose-musculoskeletal unit (AMS). The present cross-sectional study aimed to investigate differences in irisin and adiponectin concentrations between people living with HIV and healthy controls, as well as to explore potential correlations between the levels of the aforementioned adipokines and markers of calcium homeostasis. 46 HIV-infected individuals and 39 healthy controls (all men) were included in the study. Anthropometric data, adipokine levels, 25-hydroxyvitamin D [(25(OH)D)] and parathyroid hormone (PTH) concentrations were evaluated in the two groups. Correlations for the relationship between adiponectin, irisin, and PTH levels were examined. The results were adjusted for several confounders, including 25(OH)D levels, anthropometry, physical activity, bone mineral density, testosterone levels, and exposure to ultraviolet B radiation. Mean adiponectin concentrations were significantly lower in the HIV group compared to the control group: 5868 ± 3668 vs 9068 ± 4277ng/mL, p = 0.011. The same was applicable to irisin concentrations: 8.31 ± 8.17 (HIV) vs 29.27 ± 27.23 (controls) ng/mL, p = 0.013. A statistically significant and negative correlation was observed between irisin and PTH in the control group (r = - 0.591; p = 0.033). In contrast, no significant correlation was observed between PTH and irisin in the HIV group (p = 0.898). Our results are the first to suggest a possible down regulation of the inverse relationship between PTH and irisin in HIV patients and to highlight that AMS dyshomeostasis could be involved in the development of skeletal and adipose HIV-related morbidities.

Association between blood lead levels and markers of calcium homeostasis: a systematic review and meta-analysis

Chronic Pb exposure associated systemic illness are partly posited to involve calcium homeostasis. Present systematic review aims to comprehensively evaluate the association between chronic lead exposure and markers of calcium homeostasis. Observational studies documenting the changes in calcium homeostasis markers (i.e. serum calcium, parathyroid hormone, vitamin D & calcitonin) between occupationally Pb exposed group and control group were systematically searched from pubmed-Medline, Scopus, and Embase digital databases since inception to September 24, 2021. The protocol was earlier registered at PROSPERO (ID: CRD42020199503) and executed adhering to PRISMA 2020 guidelines. Mean differences of calcium homeostasis markers between the groups were analysed using random-effects model. Conventional I2 statistics was employed to assess heterogeneity, while the risk for various biases were assessed using Newcastle Ottawa Scale. Sub-group, sensitivity and meta-regression analyses were performed where data permitted. Eleven studies including 837 Pb exposed and 739 controls were part of the present study. Pb exposed group exhibited higher mean blood lead level [i.e. 36.13 (with 95% CI 25.88–46.38) µg/dl] significantly lower serum calcium (i.e. − 0.72 mg/dl with 95% CI − 0.36 to − 1.07) and trend of higher parathyroid levels and lower vitamin D levels than controls. Heterogeneity was high (I2 > 90%) among the studies. Considering the cardinal role of calcium in multiple biological functions, present observations emphasis the need for periodic evaluation of calcium levels and its markers among those with known cumulative Pb exposure.

Effect of Dipeptidyl Peptidase-4 Inhibitors on Bone Health in Patients with Type 2 Diabetes Mellitus

Patients with type 2 diabetes (T2DM) have a higher risk of bone fracture even when bone mineral density (BMD) values are normal. The trabecular bone score (TBS) was recently developed and used for evaluating bone strength in various diseases. We investigated the effect of DPP-4 inhibitors on bone health using TBS in patients with T2DM. This was a single-center, retrospective case-control study of 200 patients with T2DM. Patients were divided into two groups according to whether they were administered a DPP-4 inhibitor (DPP-4 inhibitor group vs. control group). Parameters related to bone health, including BMD, TBS, and serum markers of calcium homeostasis, were assessed at baseline and after one year of treatment. We found TBS values increased in the DPP-4 group and decreased in the control, indicating a significant difference in delta change between them. The BMD increased in both groups, with no significant differences in delta change between the two groups observed. Serum calcium and 25-hydroxy vitamin D3 increased only in the DPP-4 inhibitor group, while other glycemic parameters did not show significant differences between the two groups. Treatment with DPP-4 inhibitors was associated with favorable effects on bone health evaluated by TBS in patients with T2DM.

Dexmedetomidine Impairs Diaphragm Function and Increases Oxidative Stress but Does Not Aggravate Diaphragmatic Atrophy in Mechanically Ventilated Rats.

Anesthetics in ventilated patients are critical as any cofactor hampering diaphragmatic function may have a negative impact on the weaning progress and therefore on patients' mortality. Dexmedetomidine may display antioxidant and antiproteolytic properties, but it also reduced glucose uptake by the muscle, which may impair diaphragm force production. This study tested the hypothesis that dexmedetomidine could inhibit ventilator-induced diaphragmatic dysfunction. Twenty-four rats were separated into three groups (n = 8/group). Two groups were mechanically ventilated during either dexmedetomidine or pentobarbital exposure for 24 h, referred to as interventional groups. A third group of directly euthanized rats served as control. Force generation, fiber dimensions, proteolysis markers, protein oxidation and lipid peroxidation, calcium homeostasis markers, and glucose transporter-4 (Glut-4) translocation were measured in the diaphragm. Diaphragm force, corrected for cross-sectional area, was significantly decreased in both interventional groups compared to controls and was significantly lower with dexmedetomidine compared to pentobarbital (e.g., 100 Hz: -18%, P < 0.0001). In contrast to pentobarbital, dexmedetomidine did not lead to diaphragmatic atrophy, but it induced more protein oxidation (200% vs. 73% in pentobarbital, P = 0.0015), induced less upregulation of muscle atrophy F-box (149% vs. 374% in pentobarbital, P < 0.001) and impaired Glut-4 translocation (-73%, P < 0.0005). It activated autophagy, the calcium-dependent proteases, and caused lipid peroxidation similarly to pentobarbital. Twenty-four hours of mechanical ventilation during dexmedetomidine sedation led to a worsening of ventilation-induced diaphragm dysfunction, possibly through impaired Glut-4 translocation. Although dexmedetomidine prevented diaphragmatic fiber atrophy, it did not inhibit oxidative stress and activation of the proteolytic pathways.

Vitamin D Status is Associated With Bone Mineral Density and Bone Mineral Content in Preschool-Aged Children

This study examined the associations between vitamin D status, bone mineral content (BMC), areal bone mineral density (aBMD), and markers of calcium homeostasis in preschool-aged children. Children (n = 488; age range: 1.8–6.0 y) were randomly recruited from Montreal. The distal forearm was scanned using a peripheral dual-energy X-ray absorptiometry scanner (Lunar PIXI; GE Healthcare, Fairfield, CT). A subset (n = 81) had clinical dual-energy X-ray absorptiometry (cDXA) scans (Hologic 4500A Discovery Series) of lumbar spine (LS) 1–4, whole body, and ultradistal forearm. All were assessed for plasma 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone concentrations (Liaison; Diasorin), ionized calcium (ABL80 FLEX; Radiometer Medical A/S), and dietary vitamin D and calcium intakes by survey. Age (p < 0.001) and weight-for-age Z-score (p < 0.001) were positively associated with BMC and aBMD in all regression models, whereas male sex contributed positively to forearm BMC and aBMD. Having a 25(OH)D concentration of >75 nmol/L positively associated with forearm and whole body BMC and aBMD (p < 0.036). Sun index related to (p < 0.029) cDXA forearm and LS 1–4 BMC and whole-body aBMD. Nutrient intakes did not relate to BMC or aBMD. In conclusion, higher vitamin D status is linked to higher BMC and aBMD of forearm and whole body in preschool-aged children.

Vitamin D status among patients visiting a tertiary care center in Riyadh, Saudi Arabia: a retrospective review of 3475 cases

BackgroundVitamin D deficiency has been implicated in several chronic, non-communicable diseases independent of its conventional role in bone and calcium homeostasis. In this retrospective study, we determined the prevalence of vitamin D deficiency and its association to several cardiometabolic indices among patients visiting King Abdulaziz Medical City (KAMC), a tertiary hospital in Riyadh, Saudi Arabia.MethodsA total of 3475 charts of out-patient subjects who visited KAMC from September 2009 until December 2010 were reviewed and included. Variables of interest included measurements of vitamin D status, glycemic and renal profile, as well as trace elements (calcium and phosphorous).ResultsThe over-all prevalence of vitamin D deficiency in the cohort studied was 78.1% in females and 72.4% in males. 25(OH) vitamin D was significantly associated with increasing age and weight (p-values < 0.0001 and 0.005, respectively). It was also positively associated with albumin, calcium and phosphorous (p-values < 0.0001, < 0.0001 and 0.0007, respectively) and negatively associated with alkaline phosphatase as well as circulating levels of PTH (p-values 0.0002 and 0.0007, respectively).ConclusionIn conclusion, vitamin D deficiency is overwhelmingly common among patients seen at KAMC regardless of the medical condition, and it is significantly associated with increasing age, weight and markers of calcium homeostasis. Findings of the present study further stress the spotlight on vitamin D deficiency epidemic in the country and region in general.

Vitamin D Binding Protein Genotype Is Associated with Serum 25-Hydroxyvitamin D and PTH Concentrations, as Well as Bone Health in Children and Adolescents in Finland

Vitamin D binding protein (DBP)/group-specific component (Gc), correlates positively with serum vitamin D metabolites, and phenotype influences serum 25-hydroxyvitamin D (S-25(OH)D) concentration. The protein isoform has been associated with decreased bone mineral density (BMD) and increased fracture risk. We examined the role of GC genotypes in S-25(OH)D status and BMD in 231 Finnish children and adolescents aged 7−19 yr. BMD was measured with DXA from lumbar spine (LS), total hip, and whole body, and for 175 subjects, radial volumetric BMD was measured with pQCT. Background characteristic and total dietary intakes of vitamin D and calcium were collected. The concentrations of 25(OH)D, parathyroid hormone (PTH), calcium and other markers of calcium homeostasis were determined from blood and urine. Genotyping was based on single-nucleotide polymorphism (rs4588) in the GC gene. The genotype distribution was: GC 1/1 68%, GC 1/2 26% and GC 2/2 6%. A significant difference emerged in 25(OH)D and PTH concentrations between the genotypes, (p = 0.001 and 0.028 respectively, ANCOVA). There was also a linear trend in: Gc 2/2 had the lowest 25(OH)D and PTH concentrations (p = 0.025 and 0.012, respectively). Total hip bone mineral content was associated with GC genotype (BMC) (p = 0.05, ANCOVA) in boys. In regression analysis, after adjusting for relevant covariates, GC genotype was associated with LS BMC and strength and strain index (SSI) Z-score in both genders, and LS BMD in boys. In conclusion, the present study demonstrates the association between GC genotypes and S-25(OH)D and PTH concentrations. The results show the influence of DBP genetic variation on bone mass accrual in adolescence.

Vitamin D status and its relationship with metabolic markers in persons with obesity and type 2 diabetes in the UAE: a cross-sectional study.

Aim. To report vitamin D status and its impact on metabolic parameters in people in the United Arab Emirates with obesity and type 2 diabetes (T2D). Methodology. This cross-sectional study included 309 individuals with obesity and T2D who were randomly selected based on study criteria. Serum concentrations of 25-hydroxy vitamin D (s-25(OH)D), calcium, phosphorus, parathyroid hormone, alkaline phosphatase, glycemic profile, and cardiometabolic parameters were assessed in fasting blood samples, and anthropometric measurements were recorded. Results. Vitamin D deficiency (s-25(OH)D < 50 nmol/L) was observed in 83.2% of the participants, with a mean s-25(OH)D of 33.8 ± 20.3 nmol/L. Serum 25(OH)D correlated negatively (P < 0.01) with body mass index, fat mass, waist circumference, parathyroid hormone, alkaline phosphatase, triglycerides, LDL-cholesterol, and apolipoprotein B and positively (P < 0.01) with age and calcium concentration. Waist circumference was the main predictor of s-25(OH)D status. There was no significant association between serum 25(OH)D and glycemic profile. Conclusion. There is an overwhelming prevalence of vitamin D deficiency in our sample of the Emirati population with obesity and T2D. Association of s-25(OH)D with body mass index, waist circumference, fat mass, markers of calcium homeostasis and cardiometabolic parameters suggests a role of vitamin D in the development of cardiometabolic disease-related process.

Candesartan cilexetil protects from cardiac myosin induced cardiotoxicity via reduction of endoplasmic reticulum stress and apoptosis in rats: Involvement of ACE2-Ang (1–7)-mas axis

Candesartan cilexetil, an angiotensin (Ang) II receptor 1 blocker was reported to suppress the myocardial damage in various cardiovascular complications but the mode by which it is effective in preventing the progression of dilated cardiomyopathy (DCM) is unknown. Emerging evidences suggest that, at least, part of the benefits observed with the use of AT1 receptor blockers could be attributed to the increased Ang (1–7) levels observed during administration of these agents. Identification of the novel components of the RAS, ACE2 and Ang (1–7) receptor mas, provided essential elements for considering the existence of a vasodilator arm of the RAS, represented by the ACE2-Ang (1–7)-mas axis. In this study, rat model of DCM was prepared by injection with porcine cardiac myosin. Twenty-eight days after immunization, candesartan cilexetil was administered intraperitoneally at 1 or 10mg/kg/day to rats for four weeks. Myocardial expression of Ang receptors and markers of calcium homeostasis, endoplasmic reticulum (ER) stress and apoptosis were measured by Western blotting and histopathological staining techniques. Candesartan improved the functional markers in a dose-dependent manner and also upregulated Ang (1–7), ACE2 and mas1 in the myocardium of DCM rats. Various ER stress and apoptosis markers were attenuated and the number apoptotic cells were significantly lower in the candesartan treated rats compared with those of the vehicle group. These findings suggest that candesartan treatment prevented the progression of DCM by activation of the counter regulatory arm of the RAS and possibly through modulation of ER stress and subsequently, cardiac apoptosis.

Higher osteocalcin levels and cross-links excretion in young men born with low birth weight.

As the result of accelerated growth, the final height of infants born with low birth weight (LBW) is near to the normal. Limited data are available about the bone density and bone turnover just after completion of skeletal development. We have investigated the bone turnover and bone density in 49 apparently healthy young LBW men (age 19-21 years; 21 born small for gestational age (SGA) and 28 appropriate for gestational age (AGA)) and in 16 age-matched controls. Bone mineral density of lumbar spine, femoral neck, and radius midshaft, the markers of calcium homeostasis, biochemical parameters of bone turnover as serum osteocalcin (OC), and urinary pyridinoline (PYD) and deoxypyridinoline (DPD) levels were measured. Bone mineral densities of LBW subjects were not altered. Serum calcium (SGA: 2.44+/-0.15; AGA:2.41+/-0.17, control: 2.25+/-0.09 mmol/liter, P < 0.05), OC (SGA:23.4+/-9.9; AGA:20.8+/-7.6; control:13.3+/-4.6 ng/ml, P < 0.01), total alkaline phosphatase (AP) (SGA:201+/-61; AGA:193+/-81, control: 117+/-34 IU/liter, P < 0.01), and urinary DPD/creat (ln.values: SGA:3.10+/-0.48; AGA:3.17+/-0.46; control:2.58+/-0.57 nmol/mmol, P < 0.05) were higher, whereas fractional excretion of calcium (SGA:0.94+/-0.470; AGA: 1.03+/-0.51, control:1.31+/-0.75%, P < 0.05) was lower in both SGA and AGA groups. PTH and 25OHD were not different. Significant correlation was obtained between seCa, OC, AP, DPD and birth weight of the subjects, but feCa correlated inversely to the birth weight. It was concluded that the bone turnover of LBW men is accelerated, but well balanced in young adulthood. Further investigation is needed to describe the possible link between accelerated bone turnover and hormonal homeostasis of LBW subjects.

Effects of Isotretinoin on Bone Mineralization During Routine Therapy With Isotretinoin for Acne Vulgaris

To examine the effects of isotretinoin on bone mineralization and other markers of calcium homeostasis in individuals receiving isotretinoin for routine therapy for severe acne vulgaris. Cohort study. An academic medical center. Twenty individuals receiving isotretinoin for severe acne vulgaris. None. The primary outcome was the change in bone mineralization as measured by dual-energy x-ray absorptiometry of the lumbar spine and hip before and after isotretinoin therapy. Additional measurements included serum osteocalcin, calcium, 25-dihydroxyvitamin D, 1,25-dihydroxyvitamin D, and intact parathyroid hormone and urine hydroxyproline or calcium. No changes were noted in bone mineralization of the lumbar spine or hip. Furthermore, no alterations were noted in serum measurements of osteocalcin, calcium, 25-dihydroxyvitamin D, intact parathyroid hormone, or urine measurements of hydroxyproline or calcium. A statistically significant change was noted in 1,25-dihydroxyvitamin D when serum from before and after isotretinoin therapy was compared. The use of isotretinoin for 20 weeks for the treatment of severe acne vulgaris does not appear to have any substantial adverse effect on bone mineralization.

Calcium metabolism in Alzheimer's disease. A case-control study.

Aluminium is present in senile plaques and in neurofibrillary tangle-bearing neurones in brains of cases of Alzheimer's disease. Evidence linking aluminium absorption to calcium metabolism prompted a case-control study of physiological markers of calcium homeostasis in patients with Alzheimer's disease. Mean plasma 25-hydroxyvitamin D concentration was lower in cases than in controls but no difference in median parathyroid hormone concentrations or other evidence of altered calcium metabolism was found. The difference in 25-hydroxyvitamin D concentrations may be secondary to differences in exposure to sunlight.