Vitamin D,Parathyroid Hormone,and Heart Failure in A Chinese Elderly Population

ObjectiveHeart failure (HF) is a major cause of morbidity and mortality worldwide. Low vitamin D status has been shown to be associated with increased risk of developing cardiovascular disease. In this study, we examined the association between vitamin D and parathyroid hormone (PTH) levels and HF in and elderly population in China.MethodsA population-based cross-sectional study was conducted in the spring of 2013 among 2,047 community-dwelling healthy individuals, aged 60 to 101 years. 25-Hydroxyvitamin D (25[OH]D) was measured using a chemiluminescence assay. PTH levels were measured with an electrochemiluminescence immunoassay.ResultsA total of 2,047 participants, including 1,121 women (54.7%), were evaluated in 2013. The median concentrations of serum 25(OH)D and PTH for the entire group were 16.1 ng/mL and 41.5 pg/mL, respectively. Serum 25(OH)D and PTH levels were associated with serum N-terminal pro-brain natriuretic peptide levels and left ventricular ejection fraction in a multivariate adjusted linear regression analysis (P < .05). In logistic regression analyses, serum 25(OH)D and PTH levels were associated with a risk of HF in single and multiple regression models (P < .05). Compared with patients with 25(OH)D levels between 30.0 and 44.9 ng/mL, patients with 25(OH)D levels less than 10 ng/mL had a higher mean hazard ratio for HF (2.88; 95% confidence interval, 1.59 to 4.38).ConclusionSerum 25(OH)D and PTH levels are independently associated with risk of HF in a Chinese elderly population. (Endocr Pract. 2014;21:30-40)     

Vitamin D,Parathyroid Hormone,and Serum Lipid Profiles in a Middle-Aged and Elderly Chinese Population

ObjectivesTo explore the associations of serum vitamin D and parathyroid hormone (PTH) levels with serum lipid profiles and the risk of hyperlipidemia in a middle-aged and elderly population.MethodsA population-based cross-sectional study was conducted in the spring of 2012 among 1,203 Chinese participants, aged 52 to 101 years. 25-Hydroxyvitamin D [25(OH)D] was measured by chemiluminescence assay. (PTH) levels were measured with an electrochemilumines-cence immunoassay (ECLIA) method.ResultsA total of 1,203 participants, including 526 women (43.7%), were evaluated in 2012. The median concentrations of serum 25(OH)D and PTH for the entire group were 17.3 ng/mL and 38.3 pg/mL, respectively. Serum 25(OH)D and PTH levels were not independently associated with serum total cholesterol, triglycerides, low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol levels in a multivariate adjusted linear regression analysis of 1,027 participants not receiving antihyperlipidemic treatment (P > .05). In logistic regression analyses, serum 25(OH)D and PTH lev-els were not associated with a risk of hyperlipidemia after adjustment for age, sex, heavy drinking, smoking, diabetes, obesity, family history of hyperlipidemia, body mass index (BMI), physical activity, glomerular filtration rate (GFR), fasting glucose, high-sensitivity Creactive protein (hsCRP), calcium, and hemoglobin.ConclusionsSerum 25(OH)D and PTH levels are not independently associated with serum lipid levels or an increased risk of hyperlipidemia in a middle-aged and elderly Chinese population. (Endocr Pract. 2014;20: 556-565)     

Reduced Parathyroid Hormone-Stimulated 1,25-Dihydroxyvitamin D Production in Vitamin D Sufficient Postmenoposual Women with Low Bone Mass and Idiopathic Secondary Hyperparathyroidism

ObjectiveDistinguishing secondary hyperparathyroidism (sHPT) from eucalcemic primary hyperparathyroidism (EC-pHPT) is important. The objective of this study was to measure parathyroid hormone (PTH)-stimulated production of 1α,25-dihydroxyvitamin D (1,25[OH]₂D) in early postmenopausal patients with idiopathic sHPT, who also fit the criteria for EC-pHPT, compared to age-matched controls.MethodsIn this pilot case-control study, postmenopausal women aged 44 to 55 years with normal serum calcium (Ca), glomerular filtration rate (GFR) ≥65 mL/min, and 25-hydroxyvitamin D (25[OH]D) ≥75 nmol/L (30 ng/mL) were given an 8 hour infusion of PTH(1-34), 12 pmol/kg/h. Patients (n = 5) had elevated PTH, normal 1,25(OH)₂D, and no hypercalciuria. Controls (n = 5) had normal PTH. At baseline, 4, and 8 hours, serum Ca, creatinine (Cr), phosphorus (P), 1,25(OH)₂D, fibroblast growth factor (FGF23), and 24,25(OH)₂D as well as urine Ca, P, Cr, and cAMP/GFR were measured. The fractional excretion of calcium (FeCa) and tubular reabsorption of phosphorus (TMP)/GFR were calculated.ResultsPatients had lower 1,25(OH)₂D levels (± SD) than controls at 4 (39.8 ± 6.9 versus 58.8 ± 6.7; P = .002) and 8 hours (56.4 ± 9.2 versus 105 ± 2.3; P = .003) of PTH infusion, attenuated after adjusting for higher body mass index (BMI) in patients (P = .05, .04), respectively. The 24,25(OH)2D levels were lower in patients than controls (1.9 ± 0.6 versus 3.4 ± 0.6, respectively; P = .007). No differences were seen in serum Ca or P, urine cAMP/GFR, TRP/GFR, FeCa, or PTH suppression at 8 hours (patients 50%, controls 64%).ConclusionVitamin D sufficient patients who fit the criteria for EC-pHPT had reduced PTH-stimulated 1,25(OH)₂D compared to controls, partially attributable to their higher BMI. Other causes of reduced 1,25(OH)₂D production ruled out were excessive catabolism of vitamin D metabolites, elevated FGF23, and CYP27B1 mutation. Elevated BMI and idiopathic reduced PTH-stimulated 1,25(OH)₂D production should be considered in the differential of sHPT. (Endocr Pract. 2013;19:91-99)     

Treatment with 50000 IU Vitamin D2 Every Other Week and Effect on Serum 25-Hydroxyvitamin D2, 25-Hydroxyvitamin D3, and Total 25-Hydroxyvitamin D in Aclinical Setting

ObjectiveTo examine the effect of 50 000 IU-vitamin D₂ supplementation in a clinical setting on serum total 25-hydroxyvitamin D (25[OH]D), 25-hydroxyvitamin D₂ (25[OH]D₂), and 25-hydroxyvitamin D₃ (25[OH]D₃).MethodsThis retrospective cohort study was performed in an urban tertiary referral hospital in Boston, Massachusetts. Patients who had been prescribed 50 000 IU vitamin D₂ repletion and maintenance programs were identified through a search of our electronic medical record. Baseline and follow-up total serum 25(OH)D, 25(OH)D₂, and 25(OH)D₃ levels were compared.ResultsWe examined the medical records of 48 patients who had been prescribed 50 000 IU vitamin D₂ in our clinic. Mean ± standard deviation baseline total 25(OH) D was 31.0 ± 10.6 ng/mL and rose to 48.3 ± 13.4 ng/mL after treatment (P <.001). 25(OH)D₂ increased from 4.2 ± 4.3 ng/mL to 34.6 ± 12.3 ng/mL after treatment (P <.001), for an average of 158 days (range, 35-735 days). Serum 25(OH)D3 decreased from 26.8 ± 10.8 ng/mL to 13.7 ± 7.9 ng/mL (P <.001).ConclusionsFifty thousand IU vitamin D₂ repletion and maintenance therapy substantially increases total 25(OH)D and 25(OH)D2 despite a decrease in serum 25(OH)D3. This treatment program is an appropriate and effective strategy to treat and prevent vitamin D deficiency.(Endocr Pract. 2012;18:399-402)     

Serum 25-Hydroxyvitamin D Deficiency; A Risk Factor for Chronic Kidney Disease in Ambulatory Indigent Patients

ObjectiveTo assess whether 25-hydroxyvitamin D (25[OH]D) deficiency is a risk factor for chronic kidney disease (CKD) in ambulatory indigent patients.MethodsData for all serum 25(OH)D concentrations measured during 2010 in our ambulatory nondialysis-dependent patients were analyzed along with CKD-related parameters. Patients were stratified into groups based on 25(OH)D levels of < 10, 10 to 19, 20 to 29, and ≥ 30 ng/mL. CKD was defined by estimated glomerular filtration rate (eGFR; Chronic Kidney Disease-Epidemiology Collaboration [CKD-EPI] equation) and abnormal urine protein to creatinine ratios. CKD-associated parameters included serum parathyroid hormone (PTH), 1,25-dihydroxyvitamin D (1,25[OH]₂D), alkaline phosphatase, albumin, corrected calcium, and total CO₂ levels.ResultsA total of 2,811 patients had 25(OH)D levels measured. Patients with 25(OH)D levels < 10 ng/mL had significantly increased relative risk (RR) of an eGFR < 15 mL/min/1.73 m² (RR, 4.0), an eGFR of 15 to 29 mL/min/1.73 m² (RR, 2.6), urine protein to creatinine ratio > 3.5 g/g (RR, 5.6), and serum PTH > 100 pg/mL (RR, 2.8) compared to patients with a 25(OH)D level ≥ 30 ng/mL. Patients with 25(OH)D levels of 10 to19 ng/mL had significantly increased RR of a urine protein to creatinine ratio > 3.5 g/g (RR,4.8) and serum PTH > 100 pg/mL (RR, 1.5) compared to patients with 25(OH)D levels ≥ 30 ng/mL.Conclusion25(OH)D deficiency (< 10 ng/mL) was associated with reduced eGFR, nephrotic-range proteinuria, and increased PTH levels in our population of ambulatory urban indigent patients. (Endocr Pract. 2014;20:236-243)     

A Prospective Study of Commonly Utilized Regimens of Vitamin d Replacement and Maintenance Therapy in Adults

Objective: To determine which vitamin D dose, formulation, and schedule most effectively and safely achieves a 25-hydroxyvitamin D (25&lsqb;OH]D) level of >30 ng/mL (75 nmol/L).Methods: In this prospective study, 100 subjects from the NY Harbor HCS Brooklyn Campus, ages 25 to 85 years, with 25(OH)D <30 ng/mL (<75 nmol/L), were randomized into four groups: cholecalciferol (D3) 2,000 international units (IU) daily; D3 3,000 IU daily; ergocalciferol (D2) 50,000 IU weekly; and D2 50,000 IU twice weekly. All were supplemented with 500 mg calcium carbonate daily. 25(OH)D, parathyroid hormone (PTH), urinary calcium, urinary creatinine, and other variables were measured during 7 visits over 12 months.Results: All groups achieved a mean vitamin D level >30 ng/mL (>75 nmol/L) by visit 4 (5 months). Those receiving 50,000 IU D2 twice weekly displayed the most rapid and robust response, with 25(OH)D reaching >30 ng/mL (>75 nmol/L) after only 1 month and plateauing at 60 ng/mL (150 nmol/L) by 7 months. Although no statistically significant difference was seen in mean 25(OH)D levels between groups 1 through 3, subjects on 50,000 IU D2 weekly more consistently showed higher mean levels than either groups 1 or 2. No episodes of significant hypercalcemia occurred. There was a negative correlation in mean PTH levels and mean vitamin D levels in group 4 and all groups combined.Conclusion: All four schedules of vitamin D replacement were effective in safely achieving and maintaining 25(OH)D >30 ng/mL (>75 nmol/L). D2 50,000 IU twice weekly provided the most rapid attainment and highest mean levels of vitamin D.Abbreviations: 25(OH)D = 25-hydroxyvitamin D; BMI = body mass index; BUN = blood urea nitrogen; Ca/Cr = calcium/creatinine; D2 = ergocalciferol; D3 = cholecalciferol; IU = international units; PTH = parathyroid hormone     

Safety of Vitamin D Replacement in Patients with Primary Hyperparathyroidism and Concomitant Vitamin D Deficiency

ObjectiveTo evaluate the safety of vitamin D replacement in patients with vitamin D deficiency and primary hyperparathyroidism.MethodsRetrospective chart review of 35 patients from our endocrine clinic, age 22 to 89 years, diagnosed with primary hyperparathyroidism and vitamin D deficiency, and treated with either 1,000 to 2,000 international units (IU) of vitamin D daily or 50,000 IU of vitamin D weekly for 5 months. Data were collected before and after treatment on serum calcium, 25-hydroxyvitamin D (25-OH D), intact parathyroid hormone (iPTH), phosphorus, alkaline phosphatase, nephrolithiasis, fractures, and osteoporosis.Results25-OH D increased significantly, from a baseline of 14.65 ± 6.57 ng/mL to 42.17 ± 12.98 ng/ mL after weekly treatment with 50,000 IU of vitamin D (P<.0001), and from 22.42 ± 5.47 ng/mL to 33.33 ± 6.39 ng/mL following daily treatment with 1,000 to 2,000 IU of vitamin D (P<.0001). Pre- and posttreatment unadjusted serum calcium remained stable in the high-dose group (10.80 ± 0.43 mg/dL vs. 10.72 ± 0.67 mg/dL; P = .47), but decreased slightly in the low-dose group (10.76 ± 0.58 mg/dL vs. 10.11 ± 0.54 mg/dL; P = .0007). After adjusting for age, sex, vitamin D, and PTH levels, the small calcium difference in the low-dose group became statistically insignificant. Treatment with either high or low doses of vitamin D did not significantly change iPTH levels. Creatinine remained stable in all patients, and no new cases of nephrolithiasis were reported.ConclusionReplacing vitamin D in mild primary hyperparathyroidism is safe, effective, and does not increase calcium to dangerous levels. (Endocr Pract. 2013;19:420-425)     

Vitamin D insufficiency in diabetic retinopathy

ObjectiveTo assess the relationship between vitamin D status and diabetic retinopathy.MethodsA clinic-based, cross-sectional study was conducted at Emory University, Atlanta, Georgia. Overall, 221 patients were classified into 5 groups based on diabetes status and retinopathy findings: no diabetes or ocular disease (n = 47), no diabetes with ocular disease (n = 51), diabetes with no background diabetic retinopathy (n = 41), nonproliferative diabetic retinopathy (n = 40), and proliferative diabetic retinopathy (PDR) (n = 42). Patients with type 1 diabetes and those taking > 1,000 IU of vitamin D daily were excluded from the analyses. Study subjects underwent dilated funduscopic examination and were tested for hemoglobin A_1c, serum creatinine, and 25-hydroxyvitamin D [25(OH)D] levels between December 2009 and March 2010.ResultsAmong the study groups, there was no statistically significant difference in age, race, sex, or multivitamin use. Patients with diabetes had lower 25(OH)D levels than did those without diabetes (22.9 ng/mL versus 30.3 ng/mL, respectively; P < .001). The mean 25(OH)D levels, stratified by group, were as follows: no diabetes or ocular disease = 31.9 ng/mL; no diabetes with ocular disease = 28.8 ng/mL; no background diabetic retinopathy = 24.3 ng/ mL; nonproliferative diabetic retinopathy = 23.6 ng/mL; and PDR = 21.1 ng/mL. Univariate analysis of the 25(OH) D levels demonstrated statistically significant differences on the basis of study groups, race, body mass index, multivitamin use, hemoglobin A_1c, serum creatinine level, and estimated glomerular filtration rate. In a multivariate linear regression model with all potential confounders, only multivitamin use remained significant (P < .001).ConclusionThis study suggests that patients with diabetes, especially those with PDR, have lower 25(OH)D levels than those without diabetes. (Endocr Pract. 2012; 18:185-193)     

High Prevalence of Vitamin D Insufficiency in China: Relationship with the Levels of Parathyroid Hormone and Markers of Bone Turnover

There is a lack of large-scale studies on vitamin D status and its relationship to parathyroid hormone (PTH) and bone turnover markers in adults living in Shanghai. The objectives were to determine the prevalence of vitamin D insufficiency in Shanghai and to investigate the relationship of 25(OH)D with parathyroid function and bone turnover markers. This cross-sectional study involved 649 men and 1939 women aged 20–89 years who were randomly sampled in Shanghai. Serum concentrations of 25(OH)D, PTH, albumin, and bone turnover markers were measured. During the winter season, the prevalence of vitamin D insufficiency (<30 ng/mL) was 84% in males and 89% in females. The prevalence of vitamin D deficiency (<20 ng/mL) was 30% in males and 46% in females. With increasing serum 25(OH)D concentrations categorized as <10, 10–20, 20–30, and ≥30 ng/mL, the mean PTH and bone turnover markers levels gradually decreasd in both sexes (p<0.001). There was an inverse relationship between the serum 25(OH)D and PTH concentrations in both genders, but no threshold of 25(OH)D at which PTH levels plateaued was observed. There were modest but significantly inverse relationships between the levels of 25(OH)D and bone turnover markers, but no plateau was observed for serum 25(OH)D levels up to 40 ng/mL.     

Vitamin D Binding Protein Gene Polymorphism as a Risk Factor for Vitamin D Deficiency in Thais

ObjectiveVitamin D deficiency is related to increased risks for a number of diseases. To date, at least 3 candidate genes, vitamin D binding protein (VDBP) gene (GC), 25-hydroxylase (CYP2R1), and 7-dehydrocholes-terol reductase/NAD synthetase 1 (DHCR7/NADSYN1), have been associated with serum 25-hydroxyvitamin D (25[OH]D) levels, but their influences on the prevalence of vitamin D deficiency in relation to other known risk factors have not been clearly defined.MethodsThe study assessed 4,476 individuals aged 14 to 93 years from the Thailand 4^th National Health Examination Survey (2008-2009) and the Electricity Generating Authority of Thailand (EGAT) (2008) cohorts. The GC rs2282679 polymorphism on chromosome 4q12-q13 was genotyped by real-time polymerase chain reaction (PCR). Serum 25(OH)D was measured by liquid chromatography/tandem mass spectrometry. Vitamin D deficiency was defined as a 25(OH)D concentration < 20 ng/mL.ResultsData were expressed as mean ± SD. There were 2,747 (61.4%) males and 1,729 (38.6%) females in the study, with an average body mass index (BMI) of 23.7 ± 4.2 kg/m² and a mean total 25(OH)D of 28.9 ± 9.0 ng/mL. Serum 25(OH)D levels decreased progressively with the presence of the C allele. Using multiple logistic regression analysis, vitamin D deficiency was significantly associated with the GC rs2282679 genotype (odds ratio [OR] per C allele 1.80, 95% confidence interval CI 1.57-2.01), independent of established risk factors for vitamin D deficiency including age, sex, and BMI.ConclusionA specific GC gene polymorphism is associated with lower 25(OH)D levels independent of age, sex, and adiposity in Thai subjects. (Endocr Pract. 2015;21:221-225)     

Vitamin D levels in asymptomatic adults--a population survey in Karachi, Pakistan

Background

It is well established that low levels of 25(OH) Vitamin D (<30 ng/dL) are a common finding world over, affecting over a billion of the global population. Our primary objective was to determine the prevalence of vitamin D deficiency and insufficiency in the asymptomatic adult population of Karachi, Pakistan and the demographic, nutritional and co-morbidity characteristics associated with serum vitamin D levels.

Methods

A cross-sectional population survey was conducted at two spaced out densely populated areas of the city. Serum levels of 25OHVitamin D were measured and GFR as renal function was assessed by using 4 variable MDRD formula.

Results

Our sample of 300 had a median age of 48(interquartile range 38–55) years. The median level of serum vitamin D was 18.8 (IQ range 12.65–24.62) ng/dL. A total of 253 (84.3%) respondents had low levels (<30 ng/dL) of 25OH vitamin D. Serum PTH and vitamin D were negatively correlated (r = −0.176, p = 0.001). The median PTH in the vitamin D sufficiency group was 38.4(IQ range28.0–48.8)pg/mL compared with 44.4(IQ range34.3–56.8) pg/mL in the deficiency group (p = 0.011).The median serum calcium level in the sample was 9.46(IQ range 9.18–9.68) ng/dL. Low serum levels of vitamin D were not associated with hypertension (p = 0.771) or with an elevated spot blood pressure (p = 0.164).In our sample 75(26%) respondents had an eGFR corresponding to stage 2 and stage 3 CKD. There was no significant correlation between levels of vitamin D and eGFR (r = −0.127, p-value = 0.277).Respondents using daily vitamin D supplements had higher 25 OH vitamin D levels (p-value = 0.021).

Conclusion

We observed a high proportion of the asymptomatic adult population having low levels of vitamin D and subclinical deterioration of eGFR. The specific cause(s) for this observed high prevalence of low 25OH vitamin D levels are not clear and need to be investigated further upon.     

The Vitamin D Dose Response in Obesity

ObjectiveThe prevalence of vitamin D inadequacy is high in obese individuals. Determining the response of serum 25-hydroxyvitamin D (25[OH]D) to vitamin D₃ supplementation in obese and nonobese individuals may lead to concurrent recommendations for optimal vitamin D intake in these populations. The objective of this study was to determine the dose response of vitamin D₃ in subjects with a body mass index ≥ 35 kg/m².MethodsRandomized, double-blind, placebo-controlled study. This study is an extension of our previous study of vitamin D dosing in healthy adults. After an assessment of baseline 25(OH)D levels, participants were randomized to a vitamin D supplementation arm (100 μg daily if baseline 25[OH]D was < 50 nmol/L, or 50 μg daily if baseline 25[OH]D was ≥ 50 nmol/L) or placebo arm. Subjects with baseline 25(OH)D level ≥ 80 nmol/L were excluded from the study. Two months following randomization, a repeat 25(OH)D measurement was done.ResultsFinal analysis included 25 subjects (14 placebo, 11 active). At 2 months, serum 25(OH)D concentration increased to a mean of 75 nmol/L in the active group. Mean slope (i.e., vitamin D₃ response), defined as 25(OH) D change/baseline dose, was 0.398 nmol/L/μg/day.ConclusionThe dose response of vitamin D₃ (slope) in obese subjects was significantly lower (P < .03) at 0.398 nmol/L/μg/day compared to the slope in the previous study of healthy subjects (0.66 nmol/L/μg/day). These results suggest that obese individuals may require 40% higher vitamin D intake than nonobese individuals to attain the same serum 25(OH)D concentration. (Endocr Pract. 2014;20:1258-1264)     

Vitamin D status and response to Vitamin D(3) in obese vs. non-obese African American children

Background: Serum 25‐hydroxyvitamin D (25(OH)D) is low in obese adults. Objective: To examine serum 25(OH)D in obese (BMI >95th percentile for age) vs. non‐obese (BMI = 5th–75th percentile for age) 6–10‐year‐old African American children and compare their differences in therapeutic response to vitamin D supplementation. Methods and Procedures: In an open label non‐randomized pre‐post comparison 21 obese (OB) and 20 non‐obese (non‐OB) subjects matched for age, sex, skin color, and pubertal maturation were treated with 400 IU of vitamin D₃ daily for 1 month. Serum 25(OH)D, 1,25‐dihydroxyvitamin D (1,25(OH)₂D), parathyroid hormone (PTH), leptin, and markers of bone turnover (serum bone‐specific alkaline phosphatase (BSAP), osteocalcin (OC), and urine n ‐telopeptide cross‐links of type 1 collagen (urine NTX)) were measured. Vitamin D deficiency was defined as serum 25(OH)D ≤20 ng/ml and insufficiency as 21–29 ng/ml respectively. Results: Vitamin D deficiency occurred in 12/21 (57%) OB vs. 8/20 (40%) non‐OB at baseline (P = 0.35) and persisted in 5/21 (24%) OB vs. 2/18 (11%) non‐OB (P = 0.42) after treatment. When the cohort was stratified by the baseline levels of 25(OH)D, there were differences in the response to treatment in the obese and non‐obese cohorts. Discussion: Vitamin D deficiency was common among OB and non‐OB preadolescent African American children, and 400 IU of vitamin D₃ (2× the recommended adequate intake) daily for 1 month was inadequate to raise their blood levels of 25(OH)D to ≥30 ng/ml.     

Differencesin-Vitamin-D3-Dosing-Regimens in a Geriatric Community-Dwelling Population

ObjectiveThe adequate dose of vitamin D supple mentation for community-dwelling elderly people has not been thoroughly investigated. This study aims to determine the efficacy of a low-dose and a higher dose of vitamin D₃ in maintaining 25-hydroxyvitamin D [25(OH)D] levels at or above 30 ng/mL.MethodsThis was a single site, double-blind, ran domized exploratory clinical trial that enrolled adults 65 years of age and older. Within strata of baseline 25(OH) D levels (< 30 versus ≥ 30 ng/mL) subjects were random ized in a 1:2 ratio to receive either 400 or 2,000 IU vitamin D₃ daily for 6 months. The main outcome measures were changes in serum 25(OH)D levels according to baseline 25(OH)D levels and dose of vitamin D3.ResultsAt baseline, 41 of 105 participants (39%) had low 25(OH)D levels (< 30 ng/mL). After 6 months of vitamin D₃ supplementation, 21 of 32 participants (66%) receiving 400 IU and 14 of 59 participants (24%) receiving 2,000 IU of vitamin D₃ still had low 25(OH)D levels. Thelargest increases in serum 25(OH)D levels were observed in subjects with baseline levels < 30 ng/mL who received 2,000 IU of vitamin D daily.ConclusionRegardless of baseline 25(OH)D level, in persons 65 years of age and older, 6-month vitamin D₃ supplementation with 400 IU daily resulted in low 25(OH) D in most individuals, while 2,000 IU daily maintained 25(OH)D levels within an acceptable range in most people on this regimen. (Endocr Pract. 2012;18:847-854)     

Association of Vitamin D Status With Hospital Morbidity and Mortality in Adult Hospitalized Patients With COVID-19

ObjectiveTo determine the association between vitamin D status and morbidity and mortality in adult hospitalized coronavirus disease 2019 (COVID-19) patientsMethodsWe performed a retrospective chart review study in COVID-19 patients aged ≥18 year hospitalized at Boston University Medical Center between March 1 and August 4, 2020. All studied patients tested positive for COVID-19 and had serum levels of 25-hydroxyvitamin D (25[OH]D) results measured within 1 year prior to the date of positive tests. Medical information was retrieved from the electronic medical record and was analyzed to determine the association between vitamin D status and hospital morbidity and mortality.ResultsAmong the 287 patients, 100 (36%) were vitamin D sufficient (25[OH]D >30 ng/mL) and 41 (14%) died during hospitalization. Multivariate analysis in patients aged ≥65 years revealed that vitamin D sufficiency (25[OH]D ≥30 ng/mL) was statistically significantly associated with decreased odds of death (adjusted OR 0.33, 95% CI, 0.12-0.94), acute respiratory distress syndrome (adjusted OR 0.22, 95% CI, 0.05-0.96), and severe sepsis/septic shock (adjusted OR 0.26, 95% CI, 0.08-0.88), after adjustment for potential confounders. Among patients with body mass index <30 kg/m², vitamin D sufficiency was statistically significantly associated with a decreased odds of death (adjusted OR 0.18, 95% CI, 0.04-0.84). No significant association was found in the subgroups of patients aged <65 years or with body mass index ≥30 kg/m².ConclusionWe revealed an independent association between vitamin D sufficiency defined by serum 25(OH)D ≥30 ng/mL and decreased risk of mortality from COVID-19 in elderly patients and patients without obesity.     

Abnormalities of Vitamin D and Calcium Metabolism after Surgical Treatment of Morbid Obesity: A Study of 136 Patients

ObjectiveTo assess the effect of bariatric surgical treatment of morbid obesity on bone mineral metabolism.MethodsWe analyzed pertinent vitamin D and calcium metabolic variables in 136 patients who had undergone a malabsorptive bariatric operation. Measurements of bone mineral density (BMD), serum 25-hydroxyvitamin D (25-OHD), 1,25-dihydroxyvitamin D [1,25-(OH)₂D], parathyroid hormone (PTH), calcium, phosphorus, and alkaline phosphatase were performed. Statistical analyses assessed correlations among various factors.ResultsThe mean age (± SD) of the study group was 48.34 ± 10.28 years. Their mean weight loss was 114.55 ± 45.66 lb, and the mean duration since the bariatric surgical procedure was 54.02 ± 51.88 months. Seventeen patients (12.5%) had a T-score of -2.5 or less, and 54 patients (39.7%) had a T-score between –1.0 and –2.5. Of 119 patients in whom serum 25-OHD was measured, 40 (34%) had severe hypovitaminosis D (25-OHD < 8 ng/mL), and 50 patients (42%) had low hypovitaminosis D (serum 25-OHD 8 to 20 ng/mL). The magnitude of weight loss correlated negatively with serum 25-OHD, calcium, phosphorus, and calcium × phosphorus product values and positively with serum alkaline phosphatase level. Serum 25-OHD and calcium concentrations correlated positively with the BMD. PTH, serum 1,25-(OH)₂D, and alkaline phosphatase concentrations correlated negatively with the BMD, a reflection of the presence of secondary hyperparathyroidism, an accelerated conversion of 25-OHD to 1,25-(OH)₂D by the elevated PTH levels, and increased osteoblastic activity. The mean daily vitamin D supplementation was 6,472 ± 9,736 IU.ConclusionHypovitaminosis D and subsequent bone loss are common in patients who have undergone a bariatric surgical procedure for morbid obesity. These patients require rigorous vitamin D supplementation. (Endocr Pract. 2007;13:131-136)     

Vitamin D in adipose tissue and serum 25-hydroxyvitamin D after roux-en-Y gastric bypass

Vitamin D is stored in body fat. The purpose of this study was to determine vitamin D concentration in abdominal fat of obese patients who underwent roux‐en‐Y gastric bypass (RYGB), and to describe changes in serum 25‐hydroxyvitamin D (25(OH)D) levels in relation to loss of body fat. Subjects from a single clinic who were scheduled for RYGB were invited into the study. Abdominal subcutaneous, omental, and mesenteric fat were obtained at time of surgery. Adipose vitamin D₂ and vitamin D₃ concentrations were measured by high‐performance liquid chromatography (HPLC). Weight and serum 25(OH)D were assessed at baseline and every 3 months up to 1 year. Seventeen subjects were included, and fat samples were available from eleven. Total vitamin D content in subcutaneous abdominal fat was 297.2 ± 727.7 ng/g tissue, and a wide range was observed (4–2,470 ng/g). Both vitamin D₂ and vitamin D₃ were detected in some of the fat samples. At baseline, 25(OH)D was 23.1 ± 12.6 ng/ml. Average weight loss was 54.8 kg at 12 months, of which ～40 kg was fat mass. Despite daily vitamin D intake of ≥2,500 IU throughout the study, no significant increase in serum 25(OH)D was observed, with mean serum concentration of 25(OH)D at 1 year of 26.2 ± 5.36 ng/ml (P = 0.58). We conclude that vitamin D in adipose tissue does not significantly contribute to serum 25(OH)D despite dramatic loss of fat mass after RYGB.     

Low Vitamin D Status is Associated with Increased Thyrotropin-Receptor Antibody Titer in Graves Disease

ObjectiveVitamin D deficiency is reportedly linked to a variety of autoimmune diseases. However, the relationship between thyroid autoimmunity in Graves disease (GD) and vitamin D deficiency is unclear. The goal of this study was to determine whether increased thyroid hormone autoantibody titer is associated with vitamin D deficiency in GD patients.MethodsA total of 70 patients with GD and 70 matched control subjects were recruited to our study. The levels of 25-hydroxyvitamin D (25[OH]D), calcium, parathyroid hormone (PTH), free triiodothyronine (FT₃), free thyroxine (FT₄), thyroid-stimulating hormone (TSH), thyrotropin-receptor antibody (TRAb), thyroid-peroxidase antibody (TPOAb), and thyroglobulin antibody (TGAb) in serum collected from these patients and controls were examined.ResultsThe level of 25(OH)D in serum from TRAb-positive GD patients was significantly lower than that in serum of healthy controls or TRAb-negative patients. However, compared with control subjects, the level of PTH in serum was increased in TRAb-positive GD patients. The rate of vitamin D deficiency (defined as serum 25[OH]D < 50 nmol/L) in TRAb-positive GD patients was significantly higher than in healthy controls or TRAb-negative GD patients. The level of 25(OH)D in serum was inversely correlated with TRAb titer in serum of TRAb-positive GD patients. However, our results did not show a correlation between 25(OH)D level and the levels of TPOAb, TGAb, FT₃, FT₄, or TSH.ConclusionLow vitamin D status is associated with increased TRAb titer in GD, suggesting a possible link between vitamin D status and increased thyroid autoim-munity in GD patients. (Endocr Pract. 2015;21:258-263)     

Low Maternal Vitamin D Status during the Second Trimester of Pregnancy: A Cross-Sectional Study in Wuxi,China

BackgroundVitamin D deficiency is common in pregnant women, but an optimal serum vitamin D level during pregnancy has not been determined and remains an area of active research. Vitamin D data from large populations of pregnant Chinese women are still limited.ObjectiveTo evaluate the vitamin D status of women in Eastern China during the second trimester of pregnancy.MethodsA hospital-based, cross-sectional, observational study. Serum 25-hydroxyvitamin D [25(OH)D] concentration was measured in samples from 5823 pregnant women in Wuxi City, China (latitude: 31.5o N), from January 2011 to June 2012.ResultsThe median serum 25(OH)D concentration was 34.0 nmol/L [2.5 nmol/L 25(OH)D = 1 ng/mL 25(OH)D]. Vitamin D deficiency [defined as 25(OH)D < 30 nmol/L according to the Institute of Medicine (National Academy of Sciences, Washington, D.C., USA)] or inadequacy [25(OH)D of 30–49.9 nmol/L] was identified in 40.7% and 38.0% of the women, respectively. Only 0.9% had a 25(OH)D level ≥ 80.0 nmol/L, which is the concentration recommended as adequate by the Endocrine Society (Washington, D.C., USA). Compared with older women, younger women were more likely to be deficient in vitamin D. There were significant differences in the 25(OH)D levels according to season. The 25(OH)D levels reached peak values in September and were correlated with (r = 0.337, P < 0.001), and fluctuated with, average monthly air temperatures.ConclusionsThere is a high prevalence of Vitamin D deficiency among pregnant Chinese women, and 25(OH)D levels varied according to season and air temperature. The results of this study also suggest that currently there is a big gap between the levels of Vitamin D detected in pregnant Chinese women and the levels recommended by the Endocrine Society.     

Correlating Pre-Operative Vitamin D Status with Post-Thyroidectomy Hypocalcemia

Objective: To examine the relationship between pre-operative vitamin D status and post-thyroidectomy hypocalcemia.Methods: Retrospective study examining 264 total and completion thyroidectomies conducted between 2007 and 2011. Subjects included had a recorded 25-hydroxyvitamin D (25[OH]D) level within 21 days prior to or 1 day following surgery, did not have a primary parathyroid gland disorder, and were not taking 1,25-dihydroxyvitamin D₃ (calcitriol) prior to surgery. Some subjects were repleted with vitamin D pre-operatively if a low 25(OH)D level (typically below 20 ng/mL) was identified. Pre-operative 25(OH)D, concurrent neck dissection, integrity of parathyroid glands, final pathology, postoperative parathyroid hormone (PTH), calcium nadir and repletion, and length of stay were examined.Results: The mean pre-operative 25(OH)D for all subjects was 25 ng/mL, and the overall rate of post-operative hypocalcemia was 37.5%. Lower pre-operative 25(OH)D did not predict postoperative hypocalcemia (P =.96); however, it did predict the need for postoperative 1,25-dihydroxyvitamin D₃ administration (P =.01). Lower postoperative PTH levels (P =.001) were associated with postoperative hypocalcemia.Conclusion: Pre-operative 25(OH)D did not predict a postoperative decrease in serum calcium, although it did predict the need for 1,25-dihydroxyvitamin D₃ therapy in hypocalcemic subjects. We recommend that 25(OH)D be assessed and, if indicated, repleted pre-operatively in patients undergoing total thyroidectomy.Abbreviations: 25(OH)D = 25-hydroxyvitamin D PTH = parathyroid hormone