Moderators of the Association Between Serum Parathyroid Hormone and Metabolic Syndrome in Participants with Elevated Parathyroid Hormone: NHANES 2003-2006.

This cross-sectional study extracted data of 392 NHANES participants with elevated serum parathyroid hormone (PTH) concentrations from 2 cycles of the US National Health and Nutrition Examination Survey (NHANES) 2003-2006 and evaluated the association between serum (PTH) concentration and metabolic syndrome (MetS) to identify dietary and lifestyle factors that may modify that association. The primary outcome was MetS severity scores. Results of univariate linear regression analyses revealed that serum PTH concentrations correlated positively and significantly with MetS severity scores (ß=0.399, p=0.030). After adjusting for gender, age, race, and alcohol consumption, results of multivariate analysis revealed that increased serum PTH concentration correlated significantly with higher MetS severity scores (ß=0.413, p=0.045) in participants with moderate physical activity over the past 30 days. Serum PTH concentration also correlated significantly with higher MetS severity scores in participants with serum 25-hydroxyvitamin D deficiency (ß=0.456 and p=0.014), those without vitamin D supplementation (ß=0.524, p=0.028) and with higher protein intake (ß=0.586 and p=0.030). In conclusion, increased serum PTH concentration is associated with higher MetS severity scores in participants with elevated serum PTH at baseline. The association between PTH concentration and MetS severity is moderated by participants' physical activity levels, status of serum vitamin D, vitamin D supplementation, and daily protein intake.

Calcium Pyrophosphate Deposition Disease and Associated Medical Comorbidities: A National Cross-Sectional Study of US Veterans.

OBJECTIVE: Calcium pyrophosphate deposition disease (CPDD) is a common cause of acute and chronic arthritis, yet there are few large epidemiologic studies of CPDD. We sought to characterize CPDD in the national Veterans Affairs (VA) population. METHODS: Using data from the Department of VA Corporate Data Warehouse, patients with International Classification of Diseases, Ninth Revision, codes for CPDD seen at any VA medical center from 2010 through 2014 were matched by age and sex with control patients without CPDD. We used multivariate analysis to compare the prevalence and odds ratios (ORs) of various comorbidities, substance use, medication exposures, and arthroplasties among patients with and without CPDD. RESULTS: We identified 25,157 patients with CPDD, yielding a point prevalence of 5.2 per 1,000. The mean ± SD age was 68.1 ± 12.3 years, and 95% were male. The strongest positive associations with CPDD were hyperparathyroidism (OR 3.35 [95% confidence interval (95% CI) 2.96-3.79]), gout (OR 2.82 [95% CI 2.69-2.95]), osteoarthritis (OR 2.26 [95% CI 2.15-2.37]), rheumatoid arthritis (OR 1.88 [95% CI 1.74-2.03]), and hemochromatosis (OR 1.87 [95% CI 1.57-2.24]). Positive associations were also seen with higher odds for osteoporosis (OR 1.26 [95% CI 1.16-1.36]), hypomagnesemia (OR 1.23 [95% CI 1.16-1.30]), chronic kidney disease (OR 1.12 [95% CI 1.07-1.18]), and calcium supplementation (OR 1.15 [95% CI 1.06-1.24). Negative associations were seen with proton-pump inhibitors (OR 0.58 [95% CI 0.55-0.60]) and loop diuretics (OR 0.80 [95% CI 0.76-0.84]). CONCLUSION: Using a large national data set, we confirmed known associations with CPDD, provided support for positive associations with rheumatoid arthritis, hypomagnesemia, and osteoporosis, and suggested potential novel negative associations with commonly used medications.

Serum of 25-Hydroxyvitamin D and Intact Parathyroid Hormone Levels in Postmenopausal Women with Hip and Upper Limb Fractures.

OBJECTIVES: To assess the serum of 25-hydroxyvitamin D (25(OH)D) and intact parathyroid hormone (iPTH) levels in postmenopausal women from northern China with hip and upper limb fractures. DESIGN: Case-control. SETTING: Affiliated Hospital of Qingdao University. PARTICIPANTS: Postmenopausal women diagnosed with hip fracture (n = 335) and matched controls without fracture (n = 335). MEASUREMENTS: Between 2011 and 2013, fasting venous samples were analyzed for 25(OH)D, iPTH, alkaline phosphatase (ALP), calcium, and phosphorus. All women completed a standardized questionnaire designed to document putative risk factors for fractures. RESULTS: Eight percent of participants had vitamin D deficiency, and 66.0% had secondary hyperparathyroidism. Serum 25(OH)D levels were significantly (P < .001) lower in women with hip fracture than in controls. Multivariate logistic regression analysis adjusted for common risk factors showed that serum 25(OH)D of 20 ng/mL or less was an independent indicator of hip fracture (odds ratio (OR) = 2.98, 95% confidence interval (CI) = 2.11-4.20) and concomitant upper limb fracture in those with existing hip fractures (OR = 4.77, 95% CI = 1.60-10.12). The area under the receiver operating characteristic curve of 25(OH)D was 0.77 (95% CI = 0.68-0.84) for hip fracture and 0.80 (95% CI = 0.72-0.89) for hip and upper limb fractures. CONCLUSION: Vitamin D insufficiency and secondary hyperparathyroidism were a common problem in postmenopausal women who presented with concomitant hip and upper limb fractures, suggesting that they might contribute to the pathophysiology of fractures in postmenopausal women.

The Prevalence of Hypovitaminosis D in Patient with Fragility Hip Fracture at a Single Institution in Thailand.

Background: The proportion of people aged 65 years or older continues to increase in Thailand. Consistent with that trend, the number of fragility fracture patients is increasing. Hypovitaminosis D is one of the important factors associated with fragility fracture. Objective: To evaluate serum 25-hydroxyvitamin D (25(OH)D) level and prevalence of hypovitaminosis D in patients with fragility hip fracture in Thailand. Material and Method: This study retrospectively reviewed 25(OH)D level in fragility hip fracture patients treated at Siriraj Hospital between January 2012 and December 2015. Results: Three hundred seventy nine fragility hip fractures were included in this study. Two hundred sixty eight of those patients had serum 25(OH)D level available within one month after fracture. Mean age of patients was 80.8±8.3 years and 74.6% were women. One hundred twenty four patients (46.3%) had vitamin D deficiency (<20 ng/mL) and 86 patients (32.1%) had vitamin D insufficiency (20 to 30 ng/mL). Parathyroid hormone level was available in 159 of 268 patients, and 31.5% of those had hyperparathyroidism (PTH level >65 pg/mL). Conclusion: Orthopedists who treat fragility hip fracture should always include treatment of vitamin D deficiency in their patient management plan. Future studies should establish treatment guidelines regarding dose and duration of vitamin D supplementation in fragility hip fracture patients.

Prevalence of vitamin D deficiency in peritoneal dialysis patients.

Peritoneal dialysis (PD) patients have a high risk of developing vitamin D deficiency as 25(OH) vitamin D, the precursor of active vitamin D, is lost during dialysis. This cross-sectional study was conducted to investigate the prevalence of vitamin D deficiency among adult Saudi patients on regular PD The data was collected in the summer of 2010 from patients who were on PD for more than six months at the King Khalid University Hospital, Riyadh. We recorded the demographic and clinical parameters for all patients. Blood samples were taken for serum vitamin D level (25 OH), serum parathyroid hormone (PTH) levels and other necessary biochemical parameters. There were 27 patients (11 males and 16 females) with a mean age of 46 (15-78 ± 21) years. Five patients were on continuous ambulatory PD and 22 patients were using automated PD. The average time on PD was 27.5 (6-84 ± 18.5) months. The mean serum vitamin D 25 (OH) level was 16.1 (4.9-41.5 ± 8.23) nmol/L. Sixteen (59.2%) of the patients had levels below 15 nmol/L, while another eight patients (29.6%) had vitamin D levels between 15 and 25 nmol/L, indicating a marked deficiency. The mean serum calcium was 2.2 (1.7-2.6 ± 0.2) mmol/L and the mean serum phosphorous was 1.48 (0.64-2.22 ± 0.37) mmol/L. Fifteen patients (55.5%) had significant hyperparathyroidism (serum PTH levels above 30 pmol/L). Majority of the PD patients in our center had vitamin D deficiency. The possible reasons include chronic renal failure, dietary restrictions, loss of vitamin D and decreased exposure to sunlight.

Vitamin D, Parathormone and Associated Minerals among Students in Zagazig District, Sharkia Governorate, Egypt.

AIM: To determine the prevalence of vitamin D deficiency and associated factors among students of age 13-18 years. DESIGN: Community-based cross sectional survey. SETTING: Two schools were selected using multistage sampling techniques. SAMPLING: Cluster sampling of all enrolled students (550 students). OUTCOME MEASURES: Serum levels of 25-hydroxyvitamin D (25 OHD), parathyroid hormone and calcium. Data was collected about nutritional intake, physical activity and lifestyle variables that are potential risk factors for hypovitaminosis D. RESULTS: Hypovitaminosis D prevalence was 23.8%, of which 5.3% was deficiency and 18.5% insufficiency. Serum 25 OHD levels inversely correlated with parathyroid hormone levels (r=-0.206, P= 0.00). Low calcium and ionized calcium levels were 40.6% and 45.9%, respectively, and significantly correlated with vitamin D levels. Female students have significantly higher levels of hypovitaminosis D compared to males (29.3% to 15.0%, respectively) and the level of vitamin D significantly improved with increased age. Exposure to sun had a significant effect on vitamin D levels, and physical activity, soft drink consumption and smoking did not. Multinomial regression analysis revealed that age, sun exposure and Ca level were the only significant independent predictors of hypovitaminosis D among the studied group. CONCLUSION: Our findings revealed that hypovitaminosis D is a prevalent health problem in adolescents, especially girls, who were at higher risk, and increased age and sun exposure improved vitamin D status among the studied group. There is therefore a need to consider vitamin D supplementation for school children together with increased awareness through a health education program.

Relationship between serum intact parathyroid hormone and pruritus in hemodialysis patients.

INTRODUCTION: Pruritus is one of the most common cutaneous complications in hemodialysis patients. There is no consensus on etiologic and pathologic factors. This study is aimed to evaluate the correlation between serum intact parathyroid hormone (PTH) level and the severity of pruritus in hemodialysis patients. MATERIALS AND METHODS: In a cross-sectional study, all of the patients referred to hemodialysis center of two hospitals in Sari, Iran, were primarily examined by a dermatologist and those who had no pathologic findings were included in the study. Serum levels of calcium, phosphorus, albumin, creatinine, and intact PTH were measured and evaluated against the pruritus scores. RESULTS: A total of 153 patients were studied of whom 52.3% (n = 80) were men. The prevalence of pruritus and hyperparathyroidism were 61.4% and 60.7%, respectively, and these were not significantly different between men and women. There was a significant difference in the mean itching score between the patents with and without hyperparathyroidism (5.71 +/- 5.39 and 4.93 +/- 2.93, respectively; P = .005). Serum intact PTH level correlated with itching score in this population (r = 0.294, P < .001), while no correlations were found between itching score and other laboratory parameters. CONCLUSIONS: Our study showed that intact PTH level is correlated to the severity of pruritus in hemodialysis patients. Therefore, control of hyperparathyroidism in hemodialysis patients is very important to overcome pruritus.

Serum 25(OH)D, PTH and correlates of suboptimal 25(OH)D levels in persons with chronic spinal cord injury.

STUDY DESIGN: Cross-sectional cohort study. To describe: (1) the prevalence of suboptimal 25-hydroxyvitamin D status (serum 25(OH)D <75 nmol l(-1)) and to identify correlates of vitamin D deficiency; (2) the prevalence of secondary hyperparathyroidism (serum intact parathyroid hormone (PTH)>7.0 pmol l(-1)); and (3) the relationships between serum PTH and 25(OH)D in adult men and women with chronic spinal cord injury (SCI). SETTING: Outpatient services, including an osteoporosis clinic at a tertiary spinal cord rehabilitation hospital in Ontario. METHODS: Serum levels of 25(OH)D and intact PTH were acquired at enrollment. Clinical correlates of suboptimal vitamin D status were collected via interview and chart abstraction, and identified by univariate logistic regression analysis. Pearson correlations were run to assess the relationships between serum PTH and 25(OH)D. Significance was P<0.05. RESULTS: Thirty-nine percent of the cohort, comprised of 62 adult men and women with chronic SCI, had suboptimal serum 25(OH)D levels. Factors associated with suboptimal vitamin D levels included having vitamin D assessed in the winter months (odds ratio (OR)=7.38, P=0.001), lack of a calcium supplement (OR=7.19, P=0.003), lack of a vitamin D supplement (OR=7.41, P=0.019), younger age (OR=0.932, P=0.010), paraplegia (OR=4.22, P=0.016), and lack of bisphosphonate (OR=3.85, P=0.015). Significant associations were observed between serum PTH and 25(OH)D (r=-0.304, P=0.032) and between PTH and C-telopeptide of type I collagen (CTX-I) (r=0.308, P=0.025). Disruption of the vitamin D-PTH axis may contribute to the bone loss seen in the chronic SCI population. The threshold for optimal serum 25(OH)D levels in the chronic SCI population may be higher than in the non-SCI population. Serum 25(OH)D level are likely important risk factors contributing to declining bone mass and increased fracture risk post-SCI.

Normocalcemic hyperparathyroidism in patients with recurrent kidney stones: a disease entity or vitamin D deficiency?

This retrospective data analysis was undertaken to examine the biochemical differences between renal stone formers with normocalcemic hyperparathyroidism (NHPT) and those with normal parathyroid hormone (PTH) levels. Our goal was to ascertain whether 25-hydroxyvitamin D (25(OH)D) status related to PTH levels in this patient cohort. Our findings among 74 patients with NHPT indicate that stone formers with NHPT had significantly lower 25(OH)D levels compared to 192 controls (p = 0.0001) and that 25(OH)D is positively correlated with 1,25-dihydroxyvitamin D values (R = 0.736, p = 0.015). Sequential measurements (after 3 - 5 years), among 11 patients with NHPT who did not receive vitamin D (VitD) preparations, showed a significant increase in urinary calcium (3.43 ± 1.96 vs. 5.72 ± 3.95, p = 0.0426) without a significant change in PTH levels. VitD supplementation, to 3 patients resulted in significant PTH decrease (11.8 ± 1.8 vs. 9.8 ± 1.3, p = 0.003). Prospective studies are needed to confirm the role of vitamin supplementation in renal stone formers with NHPT.

Hyperparathyroidism and complications associated with vitamin D deficiency in HIV-infected adults in New York City, New York.

Although recent studies report a high prevalence of vitamin D deficiency in HIV-infected adults similar to that in the general population, metabolic complications of vitamin D deficiency may be worsened with HIV infection and remain insufficiently characterized. We conducted a retrospective cross-sectional cohort study to determine prevalence and correlates of vitamin D deficiency and hyperparathyroidism among HIV-infected patients attending an urban clinic. Vitamin D deficiency was defined as 25(OH)-vitamin D <20 ng/ml and insufficiency as 20 to <30 ng/ml, and hyperparathyroidism as parathyroid-hormone >65 pg/ml. We used the X(2) test to compare proportions and logistic regression to assess for associations. Among 463 HIV-infected patients, the prevalence of vitamin D deficiency was 59%. The prevalence of hyperparathyroidism was 30% among patients with vitamin D deficiency, 23% among those with insufficiency, and 12% among those with sufficient vitamin D levels. Vitamin D deficiency was associated with increased odds of hyperparathyroidism. Severe vitamin D deficiency was associated with elevated alkaline phosphatase, a marker for increased bone turnover. Although efavirenz use was associated with vitamin D deficiency, and protease inhibitor use with decreased odds of vitamin D deficiency, there was no statistical difference in rates of hyperparathyroidism stratified by combination antiretroviral therapy (cART) use. Given the increased risk of osteopenia with HIV infection and cART use, vitamin D supplementation for all HIV-infected patients on cART should be prescribed in accordance with the 2011 Endocrine Society guidelines. In HIV-infected patients with severe vitamin D deficiency or hyperparathyroidism, screening for osteomalacia and osteopenia may be warranted.

Vitamin D deficiency before bariatric surgery: should supplement intake be routinely prescribed?

BACKGROUND: Before bariatric surgery, we demonstrate a 96% rate of vitamin D deficiency in morbidly obese French patients: should supplement intake be routinely prescribed? We conducted a prospective observational study to demonstrate the prevalence of vitamin D deficiency in morbidly obese patients awaiting bariatric surgery. METHODS: Clinical and biological data were collected on 50 successive patients. RESULTS: Data showed vitamin D deficiency in 96% (25-OH vitamin D = 31 ± 13 nmol/l), with a cut-point of 50 nmol/l. Secondary hyperparathyroidism was found in 44% of patients with hypovitaminosis D (parathyroid hormone (PTH), 59 ± 24 pg/ml). Impaired PTH level concerned 89% of this group, considering the cut-point at 30 pg/ml. No significant correlation appeared between vitamin D and calcium or phosphate levels. CONCLUSIONS: Before surgery, we demonstrated a higher incidence of vitamin D deficiency in morbidly obese French patients as compared to the general population. The incidence was also higher than previous American studies. Screening for hypovitaminosis D may routinely be considered in morbid obesity. Long-term observation is, however, needed to assess the advantages and potential side effects of systematic vitamin D supplements.

Vitamin D status in relation to obesity, bone mineral density, bone turnover markers and vitamin D receptor genotypes in healthy Saudi pre- and postmenopausal women.

UNLABELLED: The various factors that may contribute to vitamin D deficiency or insufficiency were examined among healthy Saudi pre- and postmenopausal women. Vitamin D deficiency was highly prevalent among studied Saudi women with obesity, poor sunlight exposure, poor dietary vitamin D supplementation and age as the main risk factors. INTRODUCTION: The various factors that may contribute to vitamin D deficiency or insufficiency in relation to bone health among Saudi women are not known. The main objectives of the present study were to determine the factors influencing vitamin D status in relation to serum 25-hydroxyvitamin D (25(OH)D), intact parathyroid hormone (PTH), bone turnover markers (BTMs), bone mineral density (BMD), and vitamin D receptor genotype (VDR) in healthy Saudi pre- and postmenopausal women. METHODS: A total number of 1,172 healthy Saudi women living in the Jeddah area were randomly selected and studied. Anthropometric parameters, socioeconomic status, sun exposure index together with serum levels of 25(OH)D, calcitriol, intact PTH, Ca, PO4, Mg, creatinine, albumin, and biochemical BTMs were measured. BMD was measured by a dual energy X-ray absorptiometry and VDR genotypes were also determined. RESULTS: About 80.0% of Saudi women studied exhibited vitamin D deficiency (serum 25(OH)D<50.0 nmol/L) with only 11.8% of all women were considered with adequate vitamin D status (serum 25(OH)D>75 nmol/L). Secondary hyperparathyroidism was evident in 18.5% and 24.6% in pre- and postmenopausal women with 25(OH)D<50 nmol/L. Serum 25(OH)D was lower (P<0.001) and intact PTH higher (P<0.001) in the upper quintiles of body mass index (BMI) and waist-to-hip ratio (WHR). Multiple linear regression analysis showed that BMI, sun exposure index, poor dietary vitamin D supplementation, WHR, and age were independent positive predictors of serum 25(OH)D values. CONCLUSIONS: Vitamin D deficiency is highly prevalent among healthy Saudi pre-and postmenopausal women and largely attributed to obesity, poor exposure to sunlight, poor dietary vitamin D supplementation, and age.

Vitamin D deficiency and parathyroid hormone levels following renal transplantation in children.

The objectives were to determine the prevalence of vitamin D deficiency [25(OH)D < 10 ng/ml] in pediatric renal transplant (RTx) recipients, compared with controls and identify correlates of changes in 25(OH)D and intact parathyroid hormone (iPTH) levels following transplantation. Serum 25(OH)D, 1,25(OH)(2)D, and iPTH were measured once in 275 healthy controls and at transplantation, and 3 and 12 months posttransplantation in 58 RTx recipients. Multivariate logistic regression models determined the odds ratio (OR) of vitamin D deficiency in RTx recipients vs. controls adjusted for age, sex, race, and season. Generalized estimating equations were used to assess changes following transplantation. At transplantation, 22% of nonblack and 27% of black RTx recipients were vitamin D deficient. The adjusted OR of vitamin D deficiency was greater in RTx recipients (p < 0.001) compared with controls; however, the transplant association was greater in nonblack vs. black individuals (interaction p = 0.02). Overall, 25(OH)D levels did not change significantly following transplantation. Younger age (p < 0.01), nonblack race (p < 0.001), visits in nonwinter months (p < 0.001), and supplementation with ≥400 IU/day ergo/cholecalciferol (p < 0.001) were associated with increases (or lesser declines) in 25(OH)D following transplantation. Increases in 25(OH)D levels (p < 0.001) and vitamin D supplementation (p < 0.01) were associated with greater reductions in iPTH levels following transplantation, independent of 1,25(OH)(2)D levels.

Treatment with calcimimetics in kidney transplantation.

Graft and patient survival in renal transplantation has increased with better immune suppression treatment, leading to the appearance of new complications such as posttransplant bone disease. After renal transplantation and the recovery of renal function, mineral metabolism disorders secondary to renal failure could be expected to normalize. However, both immediately after transplantation and later, and even with good renal graft function, we see bone disorders associated to renal osteodystrophy, a high incidence of osteopenia, persistent hyperparathyroidism, hypercalcemia, hypophosphoremia, and less commonly, aseptic bone necrosis. The causes potentially responsible for these disorders have basically been identified as different degrees of renal insufficiency in the graft, persistent posttransplant secondary hyperparathyroidism, and negative impact of immunosuppression treatment, particularly corticosteroids. The most important factor in the evolution of metabolic and bone disorders after renal transplantation, however, is pretransplant bone status. Special attention should be paid to other osteoarticular complications such as loss of bone mass and fractures, leading to significant morbidity. In the therapeutic approach to these patients, as well as encouraging physical exercise and advice about diet or other habits, the use of drugs such as calcium and vitamin D supplements, bisphosphonates, and more recently, calcimimetics have made significant improvements in the prevention and treatment of bone-mineral metabolism. It has been shown that calcimimetic agents can control the parathyroid hormone, reduce episodes of hypercalcemia, and improve hypophosphatemia. Their properties have to be assessed in broader studies to establish the basis for their widespread use among renal transplant recipients.

Secondary causes of low bone mass in patients with breast cancer: a need for greater vigilance.

PURPOSE: An observational study to assess the prevalence of secondary causes of low bone density in patients with breast cancer. PATIENTS AND METHODS: Female patients within 5 years of breast cancer diagnosis and age older than 50 years at diagnosis were recruited. Consenting patients completed a questionnaire and had blood taken for serum calcium, vitamin D, parathyroid hormone (PTH), and thyroid function testing. Bone mineral density (BMD) was assessed. Abnormalities were additionally investigated and treated. RESULTS: Two hundred patients were recruited. The median age at diagnosis was 62 years. One hundred sixty-nine patients had hormone receptor (HR) -positive cancer. Vitamin D and thyroid function were assessed in 200 patients; PTH was assessed in 197 patients; and BMD was assessed in 187 patients. Eighty-seven patients (46.5%) had osteopenia, and 24 patients (12.8%) had osteoporosis. Vitamin D levels were insufficient (ie, 50 to 75 nmol/L) in 74 patients (37%) and were deficient (ie, < 50 nmol/L) in 54 patients (27%). Only 24 of 65 patients taking vitamin D supplements were replete (ie, > 75 nmol/L). Thirty-nine (21%) of 197 patients had PTH concentrations greater than the normal range. Six had primary hyperparathyroidism (PHPT), and two more had recent surgery for PHPT. Twenty-seven had secondary hyperparathyroidism (HPT) from vitamin D deficiency and six had normocalcemic HPT. Of 90 patients with low BMD and HR-positive cancer, 8% (seven of 90 patients) had new or recent PHPT, and 63% (57 of 90 patients) had insufficient or deficient vitamin D. More patients with HR-positive cancer than with HR-negative cancer had elevated PTH (38 of 167 v three of 30 patients, respectively; P = .10). CONCLUSION: Secondary causes of low BMD are common in postmenopausal women. Identification and management of secondary causes should be included in bone health management algorithms.

Vitamin D deficiency and hyperparathyroidism in relation to ethnicity: a cross-sectional survey in healthy adults.

BACKGROUND: The study of vitamin D status at population level gained relevance since vitamin D deficiency was recently suggested to trigger chronic disease. AIM OF THE STUDY: We aimed to describe vitamin D status, its association with bone and mineral metabolism and risk factors for deficiency in adults over 40 years in Belgium. METHODS: We conducted a cross-sectional survey in a stratified random sample of 401 subjects aged between 40 and 60 years living in Brussels, and drawn from 4 different ethnic backgrounds: autochthonous Belgian, Moroccan, Turkish and Congolese. 25-Hydroxyvitamin D (25OHD), parathyroid hormone (PTH), osteocalcin, C-telopeptide and bone mineral density was measured. RESULTS: Three-hundred and six subjects (77%) showed 25OHD concentrations below 50 nmol/l,135 (34%) below 25 nmol/l and 18 (5%) below 12.5 nmol/l. The proportion of subjects with vitamin D deficiency was four times greater amongst those of Moroccan or Turkish descent compared with those of Congolese or Belgian descent. Moroccan subjects showed a significant higher PTH and bone marker concentrations compared to Belgian. Ethnicity, season and sex were independently associated with vitamin D deficiency in multivariate analysis. CONCLUSION: The prevalence of vitamin D deficiency is very high amongst the adult population of Brussels but immigrants are at greater risk. Given the established link between population health and adequate vitamin D status, a policy of vitamin D supplementation should be considered in these risk groups.

Determinants of parathyroid hormone levels in nursing home residents.

INTRODUCTION: Elevated parathyroid hormone (PTH) levels contribute to age-related bone loss. Practitioners should be aware of iatrogenic and/or correctable determinants of PTH elevation. METHODS: We performed a cross-sectional study including 302 of 609 eligible residents at a state veterans home. Multiple regression analysis was used to determine the effect of 25-OH-D level, glomerular filtration rate (GFR), calcium supplements, diuretics, and mobility status on PTH levels. The dose of calcium carbonate and diuretics was determined as milligram per kilogram of body weight. RESULTS: The multiple regression process identified GFR, 25-OH-D level, as well as the dose of furosemide and calcium per kilogram of body weight as significant contributors to PTH. In a 70-kg resident, a daily dose of 40 mg of furosemide was associated with an increase of 22.8 pg/mL in PTH, while 500 mg of elemental calcium carbonate (in the absence of a proton pump inhibitor) was associated with a decrease of 8.7 pg/mL in PTH. An increase of 10 ng/mL in 25-OH-D was associated with a decrease of 5.7 pg/mL in PTH. DISCUSSION: Clinicians should be aware of the adverse effects of loop diuretics on urinary calcium excretion and PTH levels. Residents who ingest furosemide should be targeted to receive recommended doses of vitamin D and calcium.

Effect of gastric bypass surgery on vitamin D nutritional status.

BACKGROUND: We previously reported a 60% prevalence of vitamin D (VitD) depletion, defined as a 25-hydroxyvitamin D (25-OHD) level of < or =20 ng/mL, in morbidly obese patients preoperatively. We now report the effect of gastric bypass (GB) on the VitD nutritional status in these patients. METHODS: We prospectively studied 108 morbidly obese patients who had undergone GB. Routine postoperative supplementation consisted of 800 IU VitD and 1500 mg calcium daily. Serum calcium, parathyroid hormone, and 25-OHD were measured before and 1 year after GB. RESULTS: The mean patient age was 46 +/- 9 years, 93% were women, and 72% were white. Preoperatively and at 1 year postoperatively, the prevalence of VitD depletion and hyperparathyroidism (HPT) and the mean 25-OHD level was 53% and 44%, 47% and 39%, and 20 and 24 ng/mL, respectively. One year after GB, the percentage of excess weight loss was 67% and demonstrated significant correlations both positively with 25-OHD and inversely with parathyroid hormone. At both intervals, blacks had a greater incidence of VitD depletion than did whites, and, at 1 year after GB, HPT was more common in patients with VitD depletion (55% versus 26%, P = .002). CONCLUSION: With customary supplementation, VitD nutrition is improved after GB, but VitD depletion persists in almost one half of patients, and blacks are at a significantly greater risk than whites. HPT did not improve, and those with VitD depletion had a significantly greater rate of HPT. Additional prospective studies are needed to determine how to optimize VitD nutrition and avoid potential long-term skeletal complications after GB.

Postpartum vitamin D insufficiency and secondary hyperparathyroidism in healthy Danish women.

OBJECTIVE: To examine vitamin D status and parathyroid function in normal Danish women postpartum. DESIGN: Three cross-sectional measures during follow-up of 89 women postpartum. SUBJECTS AND INTERVENTION: We assessed vitamin D status by measuring plasma 25-hydroxyvitamin D (P-25OHD) and the degree of secondary hyperparathyroidism by measuring plasma parathyroid hormone (P-PTH) in 89 Caucasian women at three consecutive visits: (mean (range)) 23 (10-37) days (spring), 117 (95-140) days (late summer) and 274 (254-323) days (winter) postpartum. RESULTS: P-25OHD showed seasonal variations with higher values in late summer than in the other periods (P < 0.001). At the first visit, 65% received vitamin D supplements. At the following visits, almost 50% were supplemented. Vitamin D insufficiency (P-25OHD < 50 nmol/l) occurred more often during winter (28%) than in spring (14%) (Fisher's exact test, P = 0.02) or late summer (7%) (P = 0.0001). Irrespective of season, vitamin D insufficiency occurred most frequent in women who did not take vitamin D supplements (Fisher's exact test, P < 0.02). Frank vitamin D deficiency (P-25OHD < 25 nmol/l) was observed during winter in 6%. At all three periods, P-25OHD correlated inversely with P-PTH indicating secondary hyperparathyroidism at deficient vitamin D status. During spring, late summer and winter three, one and four females, respectively, had elevated plasma PTH. CONCLUSION: Vitamin D insufficiency with secondary hyperparathyroidism is a frequent finding in healthy Danish women postpartum and especially during winter. Vitamin D supplements reduced the risk of vitamin D insufficiency, especially during winter. Our results support the importance of increased alertness regarding information of pregnant and lactating women about vitamin D supplements. Furthermore, it has to be studied whether the present recommendations of an intake of 5-10 microg vitamin D/day are sufficient, especially during winter months.