Vitamin D deficiency and seasonal variation over the years in São Paulo,Brazil

Summary

Brazil is a tropical/subtropical geographic area with elevated ultraviolet (UV) radiation. We report very high prevalence of vitamin D deficiency in a large database of Brazilian subjects and show seasonal and reciprocal relationship between vitamin D and parathyroid hormone (PTH) over the years in this tropical area.

Introduction

We aim to examine the prevalence of vitamin D deficiency, characterize the temporal relationship between 25-hydroxyvitamin D levels (25(OH)D) and intact PTH (iPTH) according to seasons, and investigate potential associations between 25(OH)D levels and extra-skeletal outcomes in a Brazilian population.

Methods

We retrospectively determined population weekly mean concentrations of unpaired 25(OH)D and iPTH using 39,004 laboratory results of Brazilian individuals of both genders aged 2 to 95 years. The 25(OH)D and iPTH distributions were normalized, and the means fit with a sinusoidal function. Potential associations between 25(OH)D serum levels and inflammatory markers, fasting glucose, HbA1c and Homeostasis Model Assessment index (HOMA) were examined.

Results

Of the samples, 33.9 % had 25(OH)D serum concentrations lower than 20 ng/mL, while the vast majority (70.7 %) were found to be vitamin D deficient or insufficient (<30 ng/mL). Vitamin D deficiency was significantly higher during the winter as compared to the summer (38.4 % <20 ng/mL and 75.5 % <30 ng/mL versus 23.3 % <20 ng/mL and 62.5 % <30 ng/mL, respectively; p?<?0.001). Seasonal variation was observed for both 25(OH)D and iPTH. 25(OH)D peaks occurred in March and troughs in September. iPTH levels showed an inverted pattern of peaks and troughs with a delay of 1?±?5 week. 25(OH)D was significantly associated with inflammatory markers but not with glucose homeostasis.

Conclusions

A sinusoidal interrelationship has been detected between vitamin D and PTH in this tropical population. A large percentage of the individuals showed vitamin D deficiency. Public health strategies are needed to better understand and manage this very high and apparently contradictory prevalence of vitamin D deficiency.

     

Prevalence and correlates of 25-hydroxyvitamin D deficiency in the Chronic Kidney Disease in Children (CKiD) cohort

Background

Vitamin D plays an important role in the mineral and bone disorder seen in chronic kidney disease (CKD). Deficiency of 25-hydroxyvitamin D (25OHD) is highly prevalent in the adult CKD population.

Methods

The prevalence and determinants of 25OHD deficiency (defined as a level <20 ng/ml) were examined longitudinally in 506 children in the CKiD cohort. Predictors of secondary hyperparathyroidism and the determinants of 1,25-dihydroxyvitamin D (1,25(OH)₂D) levels were also evaluated.

Results

Deficiency of 25OHD was observed in 28 % of the cohort at enrollment. Significant predictors of 25OHD deficiency were older age, non-white race, higher body mass index, assessment during winter, less often than daily milk intake, non-use of nutritional vitamin D supplement and proteinuria. Lower values of glomerular filtration rate (GFR), serum 25OHD, calcium and higher levels of FGF23 were significant determinants of secondary hyperparathyroidism. Lower GFR, low serum 25OHD, nephrotic-range proteinuria, and high FGF23 levels were significant determinants of serum 1,25(OH)₂ D levels.

Conclusions

Deficiency of 25OHD is prevalent in children with CKD and is associated with potentially modifiable risk factors such as milk intake, nutritional vitamin D supplement use, and proteinuria. 25OHD deficiency is a risk factor for secondary hyperparathyroidism and decreased serum 1,25(OH)₂D in children with CKD.

     

Serum 25-hydroxyvitamin D level and diabetic nephropathy in patients with type 2 diabetes mellitus

Objective

Patients with chronic kidney disease have a very high prevalence of deficiency of 25-hydroxyvitamin D [25(OH)D]. We evaluate the association between 25(OH)D and diabetic nephropathy (DN) in a Chinese sample with type 2 diabetes mellitus.

Method

The subjects were patients with diabetes mellitus who were hospitalized at our hospital during the period from June 2012 to July 2014. Serum levels of 25(OH)D were tested at admission. DN was defined as a urinary albumin-to-creatinine ratio ≥30 mg/g in a random spot urine sample. Multivariate analyses were performed using logistic regression models.

Results

We found that serum 25(OH)D levels were significantly lower in diabetes with DN as compared to without DN [8.5 (IQR 6.8–11.3) vs. 13.9 (IQR 11.2–18.2) ng/ml, P < 0.0001]. Based on the ROC curve, the optimal cutoff value of serum 25(OH)D levels as an indicator for diagnosis of DN was projected to be 10.5 ng/ml, which yielded a sensitivity of 82.6 % and a specificity of 72.7 %, with the area under the curve at 0.807 [95 % confidence interval (CI) 0.764–0.849]. Multivariate logistic regression analysis adjusted for common risk factors showed that with serum 25(OH)D level ≤10.5 ng/ml was an independent indicator of DN [odds ratio (OR) = 6.559; 95 % CI 2.864–11.368].

Conclusions

Our findings suggested that diabetes with DN had lower serum 25(OH)D levels and that determination of 25(OH)D statuses might be used to identify patients at increased risk of developing nephropathy complications.

     

Serum 25-hydroxyvitamin D,parathyroid hormone,calcium intake,and bone mineral density in Spanish adults

Summary

Vitamin D insufficiency is very common among Spanish community-dwelling adult subjects. A threshold of serum 25(OH)D around 30 ng/ml would be necessary for the prevention of secondary hyperparathyroidism and hip bone loss in our population, regardless of the dairy calcium ingestion.

Introduction

This study aims to assess 25-hydroxyvitamin D—25(OH)D—status in Spanish adult subjects and to analyze its relationships with serum PTH levels, calcium intake, and bone mineral density (BMD).

Methods

A total of 1811 individuals (1154 postmenopausal women and 657 men) aged 44–93 years participated in the study. Serum 25(OH)D, intact parathyroid hormone (PTH), aminoterminal propeptide of type I collagen (P1NP), and C-terminal telopeptide of type I collagen (β-CTX) levels were measured by electrochemiluminescence. BMD was determined by dual x-ray absorptiometry (DXA) at lumbar spine, femoral neck, and total hip.

Results

Serum 25(OH)D levels were below 10, 20, and 30 ng/ml in 5, 40, and 83 % of participants, respectively. There was a significant seasonal difference in mean serum 25(OH)D, with higher levels in summer–autumn. In multivariate analysis, 25(OH)D levels were negatively correlated with age, serum PTH and creatinine, body mass index, smoking, alcohol intake, and a number of chronic diseases, but positively with dairy calcium intake. The magnitude of the difference in serum PTH according to 25(OH)D quartiles was not influenced by calcium intake. A threshold of serum 25(OH)D around 30 ng/ml was observed for serum PTH and hip BMD.

Conclusions

Vitamin D insufficiency is very common among Spanish community-dwelling adult subjects. A threshold of serum 25(OH)D around 30 ng/ml would be necessary for the prevention of secondary hyperparathyroidism and hip bone loss in our population, regardless of the dairy calcium ingestion. Programs to improve vitamin D status may be required in our country.

     

Prevalence and Determinants of Vitamin D Deficiency Among the Overweight and Obese Singaporeans Seeking Weight Management Including Bariatric Surgery: a Relationship with Bone Health

Purpose

Low vitamin D status is prevalent worldwide and has been linked to a variety of pathologies including obesity in adults. The severity of vitamin D deficiency amongst the overweight and obese Singaporeans is not well documented. The purpose of this prospective observational study was to assess the prevalence and determinants of vitamin D deficiency in a multi-ethnic Asian population referred for weight management, including those seeking bariatric surgery.

Materials and Methods

This was a cross-sectional study conducted among 111 consecutive subjects referred to a single institution weight management service in Singapore. The data collected included their anthropometric data, body mass index (BMI), body fat percentage, waist circumference, 25-hydroxyvitamin D [25(OH)D] and other bone turnover markers.

Results

The average BMI among the 111 subjects was 40.1?±?8.2 kg/m² and mean age of 40?±?10 years. Vitamin D deficiency was found in 75.7% of the population. There was a significant negative association of vitamin D with adiposity markers including BMI (r?=???0.31), body fat percentage (r?=???0.34) and waist circumference (r?=???0.26). Predictors of vitamin D deficiency included age?>?50 years, female gender, waist circumference and body fat percentage.

Conclusion

Vitamin D deficiency is prevalent among this target population in Singapore regardless of ethnicity. In particular, the elderly, females, those with larger waist circumference and body fat percentage were significantly associated with lower serum 25(OH)D level. Hence, routine screening for the overweight and obese subjects in multi-ethnic Singapore seeking weight management is indicated.

     

The incidence of the nephrotic syndrome in childhood in Germany

Background

The incidence of childhood nephrotic syndrome (NS) in Germany is not well known.

Methods

An ESPED-based nationwide collection of epidemiological data of children in 2005 and 2006.

Result

The mean age of NS at onset was 5.5 ± 3.7 years. The gender ratio of boys to girls was 1.8:1. The average length of stay was 15.5 ± 11.2 days, with younger children remaining significantly longer in hospital. Steroid-resistance was more common in children ≥8 years (p = 0.023). Focal-segmental glomerulosclerosis (FSGS) was more common in children >10 years (p = 0.029). The ratio of males to females with FSGS was 1:1.9, thus the FSGS risk for girls at onset was 3.3-times greater. Considering the available data, the incidence of NS in Germany is 1.2/100,000 in the population <18 years, of which 1.0/100,000 are steroid-sensitive.

Conclusion

Compared with international data, which primarily focused on regional and small populations, this is the largest study about the incidence of the childhood NS.

     

Maintenance of Multivitamin Supplements After Sleeve Gastrectomy

Introduction

After all bariatric procedures, multivitamin supplements are uniformly prescribed to minimize eventual deficiencies. These supplements are usually maintained long time, even during the whole life after malabsorptive techniques, while these are maintained at least during 1 year after restrictive procedures. Given that sleeve gastrectomy does not alter intestinal absorption, the supplements are possibly unnecessary, once the patient can take an adequate diet.

Patients and Methods

A prospective randomized study of patients undergoing a laparoscopic sleeve gastrectomy was performed. Patients were randomized into two groups: those patients receiving the multivitamin supplement (Multicentrum, Pfizer, 1 tablet/day) during 3 months (group 1) and those receiving the supplement during 12 months (group 2). Laboratory data were recorded: vitamins (D, B12 and folic acid) and oligoelements (calcium, iron, phosphorus, magnesium and zinc) at 3, 6 and 12 months after surgery.

Results

Eighty patients were included, 40 in each group. At 3 months, 7.5 % of the patients presented iron deficiency and 2.5 % ferritin one, similarly in both groups, that was corrected with specific extra iron supplements. At 6 months, one patient (2.5 %) in group 1 presented iron deficiency and one in group 2 vitamin D deficiency (NS). At 12 months, only one patient in group 2 presented vitamin D deficiency, treated with specific supplements.

Conclusion

The maintenance of multivitamin supplements more than 3 months postoperatively seems to be of no benefit. It is preferable monitoring laboratory values and adding specific supplements when necessary.

ClinicalTrials.gov Identifier

NCT02620137

     

Cholecalciferol Injections Are Effective in Hypovitaminosis D After Duodenal Switch: a Randomized Controlled Study

Background

By treating obesity, one of the major epidemics of this past century, through bariatric surgery, we may cause complications due to malnourishment in a growing population. At present, vitamin D deficiency is of interest, especially in patients with inferior absorption of fat-soluble nutrients after biliopancreatic diversion with duodenal switch (BPD/DS).

Methods

Twenty BPD/DS patients, approximately 4 years postoperatively, were randomized to either intramuscular supplementation of vitamin D with a single dose of 600,000 IU cholecalciferol, or a control group. Patients were instructed to limit their supplementation to 1400 IU of vitamin D and to avoid the influence of UV-B radiation; the study was conducted when sunlight is limited (December to May).

Results

Despite oral supplementation, a pronounced deficiency in vitamin D was seen (injection 19.3; control 23.2 nmol/l) in both groups. The cholecalciferol injection resulted in elevated 25[OH]D levels at 1 month (65.4 nmol/l), which was maintained at 6 months (67.4 nmol/l). This resulted in normalization of intact parathyroid hormone (PTH) levels. No changes in vitamin D or PTH occurred in the control group.

Conclusions

In BPD/DS patients, having hypovitaminosis D despite full oral supplementation, a single injection of 600,000 IU of cholecalciferol was effective in elevating vitamin D levels and normalizing levels of intact PTH. The treatment is simple and highly effective and thus recommended, especially in cases of reduced UV-B radiation.

     

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.

     

Prevalence of vitamin D insufficiency among adolescents and its correlation with bone parameters using high-resolution peripheral quantitative computed tomography

Summary

Vitamin D deficiency and insufficiency are highly prevalent among adolescents in Hong Kong, which is a sub-tropical city with ample sunshine. Vitamin D level is significantly correlated with key bone density and bone quality parameters. Further interventional studies are warranted to define the role of vitamin D supplementation for improvement of bone health among adolescents.

Introduction

The relationship between bone quality parameters and vitamin D (Vit-D) status remains undefined among adolescents. The aims of this study were to evaluate Vit-D status and its association with both bone density and bone quality parameters among adolescents.

Methods

Three hundred thirty-three girls and 230 boys (12–16 years old) with normal health were recruited in summer and winter separately from local schools. Serum 25(OH) Vit-D level, bone density and quality parameters by Dual Energy X-ray Absorptiometry (DXA) and High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT), dietary calcium intake, and physical activity level were assessed.

Results

Sixty-four point seven percent and 11.4 % of subjects were insufficient [25?≤?25(OH)Vit-D?≤?50 nmol/L] and deficient [25(OH)Vit-D?<?25 nmol/L] in Vit-D, respectively. The mean level of serum 25(OH)Vit-D in summer was significantly higher than that in winter (44.7?±?13.6 and 35.9?±?12.6 nmol/L, respectively) without obvious gender difference. In girls, areal bone mineral density (aBMD) and bone mineral content (BMC) of bilateral femoral necks, cortical area, cortical thickness, total volumetric bone mineral density (vBMD), and trabecular thickness were significantly correlated with 25(OH)Vit-D levels. In boys, aBMD of bilateral femoral necks, BMC of the dominant femoral neck, cortical area, cortical thickness, total vBMD, trabecular vBMD, BV/TV, and trabecular separation were significantly correlated with 25(OH)Vit-D levels.

Conclusion

Vit-D insufficiency was highly prevalent among adolescents in Hong Kong with significant correlation between Vit-D levels and key bone density and bone quality parameters being detected in this study. Given that this is a cross-sectional study and causality relationship cannot be inferred, further interventional studies investigating the role of Vit-D supplementation on improving bone health among adolescents are warranted.

     

Low serum 25-hydroxyvitamin D is associated with increased risk of stress fracture during Royal Marine recruit training

Summary

The aim of this study was to investigate vitamin D status and stress fracture risk during Royal Marine military training. Poor vitamin D status was associated with an increased risk of stress fracture. Vitamin D supplementation may help to reduce stress fracture risk in male military recruits with low vitamin D status.

Introduction

Stress fracture is a common overuse injury in military recruits, including Royal Marine (RM) training in the UK. RM training is recognised as one of the most arduous basic training programmes in the world. Associations have been reported between serum 25-hydroxyvitamin D (25(OH)D) and risk of stress fracture, but the threshold of 25(OH)D for this effect remains unclear. We aimed to determine if serum 25(OH)D concentrations were associated with stress fracture risk during RM training.

Methods

We prospectively followed 1082 RM recruits (males aged 16–32 years) through the 32-week RM training programme. Troops started training between September and July. Height, body weight and aerobic fitness were assessed at week 1. Venous blood samples were drawn at weeks 1, 15 and 32. Serum samples were analysed for 25(OH)D and parathyroid hormone (PTH).

Results

Seventy-eight recruits (7.2 %) suffered a total of 92 stress fractures. Recruits with a baseline serum 25(OH)D concentration below 50 nmol L^?1 had a higher incidence of stress fracture than recruits with 25(OH)D concentration above this threshold (χ² ₍₁₎?=?3.564, p?=?0.042; odds ratio 1.6 (95 % confidence interval (CI) 1.0–2.6)). Baseline serum 25(OH)D varied from 47.0?±?23.7 nmol L^?1 in February, to 97.3?±?24.6 nmol L^?1 in July (overall mean 69.2?±?29.2 nmol L^?1, n?=?1016). There were weak inverse correlations between serum 25(OH)D and PTH concentrations at week 15 (r?=??0.209, p?<?0.001) and week 32 (r?=??0.214, p?<?0.001), but not at baseline.

Conclusion

Baseline serum 25(OH)D concentration below 50 nmol L^?1 was associated with an increased risk of stress fracture. Further studies into the effects of vitamin D supplementation on stress fracture risk are certainly warranted.

     

Are radiographic indices reliable indicators for quantitative bone mineral density and vitamin D status after femoral neck fractures? A retrospective study in 112 elderly patients

Background

Radiographic parameters and indices obtained from hip x-rays are a potential tool to promptly estimate bone quality in elderly hip fracture patients. Preoperative decision in whether to use cemented or cement augmented implants might be supported by this information and thus improve patient safety. Subsequently, this study was conducted to evaluate radiographic parameters as a prescreening tool for bone quality.

Methods

A retrospective analysis of 112 elderly patients with a femoral neck fracture after low-energy trauma was performed (81 % female, 19 % male). Three radiological indices were calculated on hip x-rays: cortical index antero-posterior CTI (ap), cortical index lateral CTI (lat) and canal to calcar ratio CCR. These indices were analyzed for correlations with DXA T-Scores and serum 25-hydroxyvitamin D (25(OH)D) using the Spearman test.

Results

Median age of patients was 80 (IQR 72–86) years. A linear correlation was found for CTI (lat) and T-Score at the total hip (p?<?0.001, r?=?0.589), femoral neck (p?=?0.005, r?=?0.405) and the lumbar spine (p?=?0.002, r?=?0.299). A significant correlation was also indicated between CTI (lat) and 25(OH)D (p?=?0.002, r?=?0.293). CTI (lat) at a cut-off level of 0.4 showed a sensitivity of 79 % and a specificity of 56 % in predicting a T-score?≤??2.5 at the total hip. Gender specific analysis revealed a higher sensitivity (100 %) and specificity (73 %) of CTI (lat) at a cut-off level of 0.4 for men. For severe vitamin D deficiency (<10 ng/ml) sensitivity and specificity were 75 % and 65 %.

Conclusion

Radiographic indices as the CTI (lat) exhibit a direct correlation to BMD and serum 25OH vitamin D levels. A CTI (lat) cut-off level of 0.4 is recommended for identifying patients at risk of osteoporosis expressed by T-Scores?≤??2.5 and severe vitamin D deficiency.

     

Vitamin D supplementation improves endothelial dysfunction in patients with non-dialysis chronic kidney disease

Purpose

Hypovitaminosis D is common in chronic kidney disease (CKD) and is associated with endothelial dysfunction and cardiovascular events. This study aimed to investigate the effects of vitamin D supplementation on endothelial dysfunction in non-dialysis CKD patients.

Materials and methods

Seventy-one non-dialysis CKD patients with low vitamin D (serum 25(OH)D < 30 ng/mL) were recruited. Patients received oral cholecalciferol 50,000 units once a week for 12 weeks. Changes in endothelial function by brachial artery flow-mediated dilation (FMD), soluble vascular cell adhesion molecule-1 (sVCAM-1), and sE-selectin were studied.

Results

There was a significant increase in serum levels of 25(OH)D after cholecalciferol supplementation (33.7 ± 12.1 vs. 13.2 ± 5.4 ng/mL, P < 0.001). Multivariable regression analysis showed that higher proteinuria (β = ? 0.548, P < 0.001) and lower levels of 25(OH)D (β = 0.360, P < 0.001) at baseline were related to lower 25(OH)D level after supplementation. FMD increased significantly from 4.4 ± 1.3 to 5.1 ± 1.5% (P < 0.001), and soluble endothelial biomarkers decreased: sVCAM-1 from 926.9 ± 158.0 to 867.0 ± 129.0 ng/mL (P < 0.001), and sE-selectin 69.7 ± 15.8 to 63.3 ± 14.7 ng/mL (P < 0.001).

Conclusions

Vitamin D supplementation can improve endothelial dysfunction in pre-dialysis CKD patients.

     

Associations of total and free 25OHD and 1,25(OH)<Subscript>2</Subscript>D with serum markers of inflammation in older men

Summary

Vitamin D is hypothesized to suppress inflammation. We tested total and free vitamin D metabolites and their association with inflammatory markers. Interleukin-6 levels were lower with higher 25-hydroxyvitamin D. 1,25-dihydroxyvitamin D and free 25OHD associations mirrored those of 25OHD. However, associations for the two metabolites diverged for tumor necrosis factor alpha (TNF-α) soluble receptors.

Introduction

Vitamin D is hypothesized to suppress inflammation, and circulating 25-hydroxyvitamin D (25OHD) and inflammatory markers are inversely correlated. However, total serum 25OHD may not be the best indicator of biologically active vitamin D.

Methods

We tested serum total 25OHD, total 1,25(OH)₂D, vitamin D binding protein (DBP), and estimated free 25OHD and free 1,25(OH)₂D associations with inflammatory markers serum interleukin-6 (IL-6), TNF-α and their soluble receptors, interleukin-10 (IL-10), and C-reactive protein (CRP) as continuous outcomes and the presence of ≥2 inflammatory markers in the highest quartile as a dichotomous outcome, in a random subcohort of 679 men in the Osteoporotic Fractures in Men (MrOS) study.

Results

IL-6 was lower in men with higher 25OHD (?0.23 μg/mL per standard deviation (SD) increase in 25OHD, 95 % confidence intervals (CI) ?0.07 to ?0.38 μg/mL) and with higher 1,25(OH)₂D (?0.20 μg/mL, 95 % CI ?0.0004 to ?0.39 μg/mL); free D associations were slightly stronger. 25OHD and DBP, but not 1,25(OH)₂D, were independently associated with IL-6. TNF-α soluble receptors were inversely associated with 1,25(OH)₂D but positively associated with 25OHD, and each had independent effects. The strongest association with ≥2 inflammatory markers in the highest quartile was for free 1,25(OH)₂D (odds ratios (OR) 0.70, 95 % CI 0.54 to 0.89 per SD increase in free 1,25(OH)₂D).

Conclusions

Associations of 1,25(OH)₂D and free 25OHD with IL-6 mirrored those of 25OHD, suggesting that 1,25(OH)₂D and free D do not improve upon 25OHD in population-based IL-6 studies. However, associations for the two metabolites diverged for TNF-α soluble receptor, warranting examination of both metabolites in studies of TNF-α and its antagonists.

     

Serum 25-Hydroxyvitamin D in Obese Spanish Adults: the Camargo Cohort Study

Objectives

To describe the 25(OH)D status in Spanish obese postmenopausal women and men ≥?50 years, to compare their results with those of the overweight or normal weight population, and to determine whether differences are observed between both sexes and with seasonal variation throughout the year.

Patients and Methods

We studied 2597 subjects (1826 postmenopausal women and 771 men ≥?50 years). Serum concentrations of 25(OH)D, intact parathyroid hormone (PTH), aminoterminal propeptide of type I collagen (PINP), and C-terminal telopeptide of type I collagen (CTX) were determined by electrochemiluminiscence (Elecsys 2010, Roche). Bone mineral density (BMD) was measured by DXA. Participants were divided according to body mass index (BMI) groups (normal ≥?20 and <?25 kg/m², overweight ≥?25 and?<?30 kg/m², or obese ≥?30 kg/m²).

Results

Obese people had lower serum 25(OH)D values (20.9?±?8.2 ng/ml) than overweight (23.3?±?8.8 ng/ml; p?<?0.0001) or normal-weight subjects (24.4?±?8.9 ng/ml; p?<?0.0001). They have also lower levels of both PINP and CTX. In contrast, PTH concentrations and BDM values were higher in obese individuals. When stratifying by sex, the difference in serum concentration of 25(OH)D remained significant in women, but not in men, persisted throughout the year, and was inversely correlated with BMI and waist circumference.

Conclusions

Despite lower serum 25(OH)D concentrations and higher PTH levels, obese and overweight women have higher lumbar spine and hip BMD and lower bone remodeling markers than normal weight women, suggesting that low serum 25(OH)D levels do not negatively affect bone health.

     

Association of 25-hydroxyvitamin D with areal and volumetric measures of bone mineral density and parathyroid hormone: impact of vitamin D-binding protein and its assays

Summary

A comparison of the association of different forms of 25-hydroxyvitamin D [25(OH)D] with parathyroid hormone (PTH) and with areal and volumetric bone mineral density (BMD) demonstrated that bioavailable and free 25(OH)D do not provide a better index of vitamin D status in terms of bone health compared to total 25(OH)D.

Introduction

This study aims to compare measures of vitamin D-binding protein (DBP) using a monoclonal versus polyclonal ELISA and assess correlations of total versus estimated free and bioavailable 25(OH)D with BMD and PTH concentrations.

Methods

DXA and peripheral quantitative CT (pQCT) scans were obtained in 304 adults (158 black, 146 white), ages 21–80 years. Free and bioavailable 25(OH)D were calculated from total 25(OH)D, DBP, and albumin concentrations. Multivariable linear regression with standardized beta coefficients was used to evaluate associations of bone measures and PTH with total, free, and bioavailable 25(OH)D.

Results

Measures of DBP obtained using a monoclonal versus polyclonal ELISA were not correlated (r _s?=?0.02, p?=?0.76). Free and bioavailable 25(OH)D based on the polyclonal assay were lower in black versus white participants (p?<?0.0001); this race difference was not evident using the monoclonal assay. Adjusted for age, sex, calcium intake, and race, all forms of 25(OH)D were negatively associated with PTH, but the absolute coefficient was greatest for total 25(OH)D (?0.34, p?<?0.001) versus free/bioavailable 25(OH)D (?0.18/?0.24 depending on DBP assay, p?≤?0.003). In analyses stratified on race, none of the measures of 25(OH)D were associated with BMD across DXA and pQCT sites.

Conclusions

The monoclonal versus polyclonal ELISA yielded highly discrepant measures of DBP, particularly among black individuals, likely related to established race differences in DBP polymorphisms. Contrary to prior studies, our findings indicate that using DBP to estimate bioavailable and free 25(OH)D does not provide a better index of vitamin D status in terms of bone health.

     

Serum vitamin D level may be a novel potential risk factor for premature ejaculation: a comparative study

Purpose

To compare serum level of vitamin D [25(OH)D] in patients with life-long premature ejaculation (LPE) versus healthy controls.

Methods

Healthy married potent males were recruited from February 2017 to January 2018. Group A included 40 patients suffering from LPE who were compared versus 40 healthy controls (Group B). Participants suffering from hormonal disorders, obesity, neurological, psychological, or chronic diseases or taking medications that may affect ejaculatory function, serum level of vitamin D, or the accuracy of intra-vaginal ejaculation latency time (IELT) were excluded. LPE was self-reported by the patients with subsequent feelings of frustration and measured by premature ejaculation diagnostic tool (PEDT) and IELT using stopwatch handled by their partners. 25(OH)D was measured by obtaining 2 ml of venous blood. Statistical analysis was performed using Student t, Mann–Whitney, Chi square tests, logistic regression analysis, and Spearman correlation.

Results

Sixteen (20%) participants had vitamin D insufficiency/deficiency. All of them were in PE group. 25(OH)D correlated significantly with IELT (r²?=?0.349; p?<?0.001) and PEDT (r²?=?0.425; p?<?0.001). There was no statistically significant difference in age (p?=?0.341), BMI (p?=?1) or IIEF-5 (p?=?0.408) in both groups. 25(OH)D was significantly lower in patients than controls (35.75 vs. 58.92 ng/ml, p?<?0.001). ROC analysis revealed that the best cut-off value of 25(OH)D to detect patients suffering from LPE was 50.65 ng/ml with a sensitivity and specificity of 85% for both. 25(OH)D remained a significant risk factor for LPE in the logistic regression analysis (p?<?0.001).

Conclusions

The current study showed that vitamin D has significant association with LPE and correlates significantly with IELT and PEDT.

     

Vitamin D deficiency in adult fracture patients: prevalence and risk factors

Purpose

Although vitamin D levels are not routinely monitored in outpatient fracture patients, identification of fracture patients with a deficient vitamin D status may be clinically relevant because of the potential role of vitamin D in fracture healing. This study aimed to determine the prevalence of and risk factors for vitamin D deficiency in non-operatively treated adult fracture patients.

Patients and methods

Vitamin D levels were determined in a cross-sectional study of adult patients, who were treated non-operatively for a fracture of the upper or lower extremity in the outpatient clinic of a level 1 trauma center, during one calendar year. Potential risk factors for (severe) vitamin D deficiency were analyzed using multivariable logistic regression analysis.

Results

A total of 208 men and 319 women with a mean age of 49.7 years (SD 19.9) were included. In this population, 71 % had a serum calcidiol <75 nmol/L, 40 % were vitamin D deficient (serum calcidiol <50 nmol/L) and 11 % were severely vitamin D deficient (serum calcidiol <25 nmol/L). Smoking and season (winter and spring) were independent risk factors for vitamin D deficiency. An increasing age, a non-Caucasian skin type, winter and smoking were identified as independent risk factors for severe vitamin D deficiency. The use of vitamin D, alcohol consumption and higher average daily sun exposure were independent protective factors against (severe) vitamin D deficiency.

Conclusion

Given the potential role of vitamin D in fracture healing, clinicians treating adult fracture patients should be aware of the frequent presence of vitamin D deficiency during the winter, especially in smoking and non-Caucasian patients. Research on the effect of vitamin D deficiency or supplementation on fracture healing is needed, before suggesting routine monitoring or supplementation.

     

Serum Parathyroid Hormone and 25-Hydroxyvitamin D Concentrations Before and After Biliopancreatic Diversion

Background

Biliopancreatic diversion with duodenal switch (BPD-DS) decreases vitamin D and calcium absorption, which may result in secondary hyperparathyroidism. This study aimed at evaluating the prevalence of vitamin D deficiency and secondary hyperparathyroidism before and after BPD-DS.

Methods

A retrospective analysis of patients who had undergone BPD-DS at a tertiary bariatric center between 2003 and 2010 and for whom simultaneous measurements of serum 25-hydroxyvitamin D and parathyroid hormone were available within 5 years post-op was performed. The prevalence of vitamin D deficiency (<?20 ng/ml) and secondary hyperparathyroidism (>?65 pg/mL) at different time points was calculated.

Results

Included were 1436 patients (mean?±?SD, age 42.7?±?10.4 years; BMI 51.5?±?8.6 kg/m²; 69.8% women). Prevalence of vitamin D deficiency decreased up to 6–12 months after surgery (from 35.8% at baseline down to 6–9%) then rose progressively, plateauing at 15.5% after 36 months. Prevalence of hyperparathyroidism was 28.5% before surgery and rose progressively after surgery, reaching 68.6% at 5 years. Mean serum corrected calcium increased from 0 to 6 months then decreased up to 36 months. Preoperatively, the prevalence of hypocalcemia was 7.3%. It increased after 12 months, attaining 26.9% at 48 months.

Conclusions

Prevalence of vitamin D deficiency and secondary hyperparathyroidism is high before BPD-DS. Despite a low prevalence of vitamin D deficiency after surgery, prevalence of hyperparathyroidism increased steadily 1 year after surgery, preceded by a decrease in serum calcium. Factors explaining the high prevalence of secondary hyperparathyroidism after BPD-DS and its long-term impact on bone health should be addressed.