Categories Of Vitamin Research Articles

Vitamin D deficiency and thyroid cancer: is there a true association? A prospective observational study.

Literature data indicate a correlation between vitamin D deficiency and thyroid cancer (TC). We conducted this observational study to test this hypothesis. We studied 327 consecutive thyroidectomy cases, and compared patients with TC and those who had benign thyroid disease (BTD). In total, 183 cases with well-differentiated TC (group B) were compared with 144 cases of BTD (group A). We defined 25-hydroxyvitamin D (25(OH)VitD) values <10ng/ml as severe vitamin D deficiency (15.4%), 10-30ng/ml as inadequacy (70.4%) and >30ng/ml as adequate (14.2%). We further used a cut-off point of 30ng/ml (used in a recent meta-analysis) to classify patients as vitamin D deficient or not. There was no statistically significant difference in the following: age, size of the thyroid gland, preoperative calcium levels, preoperative parathormone and vitamin D levels, body mass index and anti-thyroid antibodies. Only thyroid-stimulating hormone and weight of the thyroid gland were found to differ. There was no significant difference in mean vitamin D levels (group A = 19.82ng/ml [sd 9.59] vs group B = 19.69ng/ml [sd 11.34]; p = 0.917). The same was found when we compared the two groups according to the three categories of vitamin D values (deficiency, inadequacy, adequacy; p = 0.485) and when we performed the analysis based on all threshold levels (10, 20 and 30ng/ml; p = 0.328). Using various statistical methods, no correlation was found between vitamin D deficiency and differentiated TC (overall, microcarcinomas, macrocarcinomas). Based on our results, no correlation between vitamin D deficiency and TC was confirmed, contradicting and questioning the results of two recent meta-analyses.

Vitamin D as a biomarker in predicting sepsis outcome at a tertiary care hospital

Background: Vitamin D has proven immunomodulatory effects. As per the literature, there is a vitamin D deficiency observed in critically ill sepsis patients. Aims and Objectives: The present study was conducted to study the association of vitamin D levels at the time of admission to the intensive care unit (ICU) with mortality and various indices of sepsis assessment like the simplified acute physiology score (SAPS II) along with the age-unadjusted Charlson Comorbidity Index (CCI) and procalcitonin. Materials and Methods: A single centric, observational-longitudinal study was conducted in the ICU with patients of sepsis (n=96). Vitamin D was measured at the time of admission to the ICU. Controls were taken from age- and gender-matched patients without sepsis and with no premorbid illnesses. The objectives of the current study were to assess SAPS II and CCI scores and their predicted mortality amongst various categories of vitamin D levels at the time of admission, to correlate various categories of vitamin D levels with hospital stay and complications or hazards and to assess the sensitivity of vitamin D for prediction of sepsis outcome. Results: The case cohort and controls had average vitamin D levels of 15.33 ng/dL and 41.11 ng/dL, respectively. Patients with vitamin D deficiency had longer hospital and ICU stays and greater rates of morbidity. Observations showed no correlation between vitamin D and serum albumin, WBC count, total cholesterol, triglycerides, LDL, or HDL. The level of vitamin D at the time of admission to the ICU was observed to be highly sensitive (90.6%) to predicting the mortality rates in the ICU due to sepsis. Conclusion: Measurement of vitamin D at the time of admission may be a possible indicator for prediction of sepsis mortality and hospital and ICU length of stay for ICU-admitted patients with sepsis.

Serum vitamin D levels can be predictive of psoriasis flares up after COVID-19 vaccination: a retrospective case control study.

Many patients with chronic inflammatory dermatosis such as psoriasis usually ask about the safety of COVID-19 vaccination and if it would affect the course of their disease. Indeed, many case reports, case series and clinical studies, reporting psoriasis exacerbation following vaccination against COVID-19, were published during the pandemic. Also, many questions arise regarding the existence of exacerbating factors of these flare ups, including environmental triggers such as the insufficiency of vitamin D levels. This is a retrospective study that measures alterations in psoriasis activity and severity index (PASI) not exceeding 2 weeks after the first and second dose of COVID-19 vaccinations in the reported cases and assesses whether such changes have any association with patients' vitamin D levels. We retrospectively reviewed the case records of all patients with a documented flare up after COVID-19 vaccination in our department as well as those who did not, during a year. Among them, we found 40 psoriasis patients that had reported vitamin D levels in the form of 25-hydroxy-vitamin D within 3 weeks after vaccination, including 23 with exacerbation and 17 without exacerbation. Performing χ2 and t-test controls for psoriasis patients with and without flare-ups, a statistically significant dependence emerged in the seasons of summer [χ2(1) = 5.507, p = 0.019], spring [χ2(1) = 11.429, p = 0.001] and in the categories of vitamin D [χ2(2) = 7.932, p = 0.019], while the mean value of vitamin D for psoriasis patients who did not have exacerbation (31.14 ± 6.67 ng/mL) is statistically higher [t(38) = 3.655, p = 0.001] than the corresponding value of psoriasis patients who had an exacerbation (23.43 ± 6.49 ng/mL). This study indicates that psoriasis patients with insufficient (21-29 ng/mL) or inadequate (<20 ng/mL) levels of vitamin D are more prone to postvaccination aggravation of the disease while vaccination in summer, a period with the most extent photo-exposition, can be a protective factor.

Association of Serum Vitamin D level and COVID-19 infection: A Case-control Study.

Vitamin D is considered a potent modulator of the immune system, albeit its role in COVID-19 infection is a matter of debate. The present study aimed to estimate the association between serum vitamin D levels and COVID-19 among people in Qatar. This case-control study, approved by the Institutional Review Board of Primary Health Care Corporation (PHCC) Qatar, retrospectively evaluated the principal public healthcare sector population data repository retrieved from the cloud-based Electronic Health Record (EHR) software-Cerner, during April 2020-2021. The health records of all adult patients aged >18 years who had undergone the reverse transcription-polymerase chain reaction (RT-PCR) test and whose medical records had documented serum 25-hydroxyvitamin D [25 (OH)D] levels were analyzed. A total of 924,173 EHRs were extracted, of which 62,451 EHR comprised of 16,446 (26.3%) COVID-19 patients and 46,005 (73.7%) negative-control group patients met the inclusion criteria. The odds ratio (OR) among different categories of vitamin D deficiency (VDD) revealed that people with mild/moderate VDD were 1.18 times (95% CI 1.126-1.258) and those with severe VDD were 1.90 times (95% CI 1.116-1.251) more likely to have COVID-19 infection when compared to the people with optimal serum vitamin D level. On applying multiple logistic regression, the odds of having COVID-19 infection were found to be 1.27 times (95% CI 1.184-1.371) higher among those with mild/moderate VDD and 1.32 times (95% CI 1.206-1.405) higher among those with severe VDD when compared to people with optimal vitamin D level (p<0.001). Our findings demonstrated a significant association between the suboptimal serum vitamin D level and COVID-19 infection. Further studies are required to determine the effects of VDD on the severity and outcomes of COVID-19 infections.

73 PREVALENCE OF SECONDARY HYPERPARATHYROIDISM BY VITAMIN D STATUS IN OLDER IRISH ADULTS

Abstract Background Secondary hyperparathyroidism commonly results from vitamin D deficiency and can lead to accelerated bone turnover and bone loss, especially at cortical sites like the hip. It can also attenuate the response to antiresorptive treatments used for osteoporosis. However, several factors may influence PTH response. We aimed to identify the prevalence of secondary hyperparathyroidism by categories of vitamin D status in older Irish adults attending a bone health clinic. Methods The study population consisted of older adults (aged over 60 years) attending a bone health clinic at a large hospital. Participants with a serum calcium &amp;gt;2.5 mmol/l and eGFR &amp;lt;30 ml/min were excluded to avoid cases of primary hyperparathyroidism or elevated serum PTH due to advanced renal disease. Hyperparathyroidism was defined as a serum PTH &amp;gt; 65 pg/ml. 25 hydroxyvitamin D (25(OH)D) was measured with liquid chromatography mass spectroscopy. Results There were 800 cases identified, mean age 72.9 +/- 7.9 years, and 85.3% were female. The prevalence of secondary hyperparathyroidism by 25(OH)D categories were 28.1% (&amp;lt;30nmol/l), 17.4% (30-49.9 nmol/l) and 8.0% (50-74 nmol/l). Older age (P &amp;lt; 0.03) and lower eGFR (P = 0.01) were associated with hyperparathyroidism independent of vitamin D status. Conclusion Nearly one-third of patients who were vitamin D deficient (&amp;lt;30 nmol/L) and one-sixth who were insufficient (30-49.9 nmol/l) had hyperparathyroidism, similar to the results of other studies. However, hyperparathyroidism was also observed in 8% of those with 25(OH)D levels between 50 -74 nmol/l, suggesting that higher levels i.e. ≥ 75 nmol/l may be preferable in older adults. Lower eGFR and older age were also independently associated with higher PTH, consistent with previous research. Higher dietary and supplemental calcium intake is also known to suppress PTH response, though we were not able to account for this in our study.

Additive effects of obesity and vitamin D insufficiency on all-cause and cause-specific mortality.

Obesity and vitamin D deficiency are both considered risk factors for mortality, but the potential additive effects of vitamin D status and obesity on mortality has not been well-studied. We aimed to examine the possible additive effects of obesity and vitamin D status on all-cause and cause-specific mortality. The data from the NHANES III (1988-1994) and NHANES 2001-2014 surveys were used, and multivariate Cox regression models were performed to assess the additive effects of vitamin D status and overweight/obesity/abdominal obesity on the all-cause, cardiovascular and cancer mortality, by stratifying Cox Hazard Ratios (HRs) across different categories of vitamin D status and body mass index (BMI) and waist circumference (WC) categories. The models were adjusted for age, race/ethnicity, gender, educational level, family income to poverty ratio, leisure-time physical activity, smoking, and drinking. Across all BMI/WC categories, there was an additive effect of the vitamin D both insufficiency and deficiency on all mortality rates, with deficiency having much stronger effect than insufficiency. Interestingly, the effect of vitamin D deficiency overcame the effect of obesity on all mortality rates. The highest HRs for overall and cardiovascular mortality were observed among vitamin D deficient obese/abdominally obese subjects, while for cancer mortality among vitamin D deficient normal weight/non-abdominally obese subjects. In stratified analyses, regarding all-cause mortality, there was an additive effect of the vitamin D both insufficiency and deficiency in all BMI/WC categories. Regarding cardiovascular mortality, there was an additive effect of vitamin D deficiency in all BMI/WC categories, but the additive effect of vitamin D insufficiency reached significance only in normal weight subjects. Regarding cancer mortality, the effect did not reach significance among obese subjects for vitamin D deficiency, while for insufficiency, significance was reached only among non-abdominally obese subjects. Interestingly, vitamin D surplus was associated with increased risk for cancer mortality in obese subjects, but there was an inadequate number of subjects in this category to make proper judgment. In conclusion, vitamin D insufficiency and deficiency gradually increase risk for mortality across all BMI/WC categories. In our analyses, vitamin D deficiency overcame the effect of obesity on mortality rates.

Type II Diabetes and Vitamin D Levels Interdependence Among Working Old Adults

Objective: Due to the increase in the development of chronic Type II Diabetes among old working adults due to the role and levels of Vitamin D. The research was conducted for the exploration of the same research topic. This research aims to investigate the association between type II diabetes and vitamin D levels in the old working adults (above the age of 45 years). Materials and Methods: This cross-sectional research was conducted in the premises of Lahore which included a total of 1821 working employees of various institutes, firms and companies. The study included males (83%) and females (17%). The mean age of the research participants was 52±5.5 years. A self-report was used for the assessment of the sociodemographic data of the individuals included in the research. Fasting Plasma Glucose (FPG) and Glycosylated Hemoglobin (HbA1c) were assessed by blood samples for the determination of diabetes and vitamin D level status. We included four categories of vitamin D including &lt;10, 10-19.9, 20-29.9 and ≥30 with measuring unit as ng/ml. Respective Bivariate associations between the composite indicator and vitamin D categories for diabetes mellitus were either self-reported or FPG ≥ 126 mg/dl / HbA1c ≥ 6.5%. Further associations were also made through multivariate models in order to investigate potential controlling cofounders. Results: Increasing FPG has a direct association with severe vitamin D level deficiency (&lt;10 ng/ml) for the FPG values of β, 95% Confidence Interval and P-Value respectively 3.13; 0.78, 5.47 and ≤0.01 and HbA1c values for β, 95% Confidence Interval and P-Value respectively 0.15; 0.08, 0.23 and ≤0.001) which were adjusted in the linear regression models. Multivariate models show that after controlling potential models diabetes mellitus was also associated with deficiency of vitamin D levels with values of OR, 95% Confidence Interval and P-Value respectively 2.55; 1.16, 5.62 and ≤0.05). Practical implication: Vit-D can be used as an essential dose for older DM patients. Conclusion: The outcomes of the research reflect that there is an association between deficiency of vitamin D and diabetes mellitus among older working adults working in different corporate and commercial sectors. The identification of risk is unique with respect to the location and working environment of the individuals who were screened for diabetes mellitus. Keywords: Cardiovascular disease, 25-hydroxyvitamin D, diabetes mellitus (DM), older adults.

Vitamin D status is favorably associated with the cardiovascular risk factors in adults with obesity.

Previous investigations have been indicated that vitamin D deficiency is an amendable risk for cardiovascular disease (CVD) in the general populations. Limited data is available concerning the relationship of vitamin D status and risk factors of CVD in the individuals with obesity and the existing data are highly controversial. We investigated whether serum vitamin D situation is related to multiple traditional CVD risk factors in Iranian obese subjects. A cross-sectional study was done among 214 Iranian adults with obesity (94 males and 120 females) aged 20-60 years, who attended the specialized outpatient clinics in Zabol city. Participants were categorized as vitamin D sufficient, insufficient, and deficient according to their serum 25(OH)D concentrations. Afterward, the presence of hypercholesterolemia, hypertriglyceridemia, low high-density lipoprotein cholesterol (HDL-C), high low-density lipoprotein cholesterol (LDL-C) as well as diabetes, hypertension, and high serum concentrations of high-sensitivity C-reactive protein (hs-CRP) as CVD risk factors were evaluated in the participants. There was a noticeable regular trend regarding hypercholesterolemia (p=0.008), high LDL-C (p=0.024), hypertension (p=0.021), and high hs-CRP (p<0.0001) across various categories of vitamin D status. In adjusted model, vitamin D-deficient subjects were at higher risk for having hypercholesterolemia (OR: 3.22, p=0.031), high LDL-C (OR: 2.37, p=0.047), hypertension (OR: 2.32, p=0.042), and high hs-CRP (OR: 5.49, p=0.001) than ones with sufficient vitamin D status. Vitamin D deficiency in obese subjects was found to be strongly related to higher risk of unfavorable lipid profile, hypertension, and high hs-CRP.

Serum 25-hydroxyvitamin D measurement: Comparative evaluation of three automated immunoassays

Objectives: the different analytical methods for measurement of serum 25-hydroxyvitamin D (25(OH)D) are not yet fully harmonized and no consensus exists on a threshold of 25(OH)D defining a deficiency status. In this study, we compared the results from the assays of serum 25(OH)D performed with three different methods to evaluate the presence of potential biases and how much these biases can influence the assignment of patients to specific 25(OH)D deficiency/sufficiency categories. Design and Methods: Liaison 25(OH) Vitamin D Total (DiaSorin Liaison XL), Elecsys Vitamin D Total II (Roche Elecsys) and Lumipulse G25(OH) Vitamin D (Fujirebio Lumipulse G1200) were used. Methods comparability was established performing Passing-Bablok regression and Bland-Altman analysis to prove whether the differences found were lower than the preliminarily pre-established maximum acceptable bias. Results: all Passing-Bablok regressions exhibited the presence of a proportional and constant systematic error. Bland-Altman analysis revealed biases well above the maximum acceptable bias, so the 25(OH)D concentrations measured were not comparable. To evaluate whether the three methods had the same ability to classify patients into different categories of vitamin D levels, we categorized results obtained by each method in reference classes. Lumipulse categorized most patients into the class with the lowest 25(OH)D concentrations (<20 ng/mL) whereas Elecsys ranked the lowest number. Conclusions: Liaison XL and Elecsys have shown good accuracy compared to Lumipulse in measuring 25(OH)D levels. Nevertheless, the assays were not interchangeable due to the lack of comparability of results as well as to the disagreement in classification of hormone deficiency or sufficiency.

Relationship between Serum 25(OH)D Levels and Blood Pressure in Children with Nephrotic Syndrome

BACKGROUND: Vitamin D plays an eminent role in the renin-angiotensin system that may interfere with blood pressure regulation. Children with nephrotic syndrome (NS) are often observed with low serum vitamin D levels that may lead to Vitamin D deficiency status. AIM: This study aimed to investigate the correlation between serum vitamin D [25(OH)D] levels and blood pressure in children with NS. METHODS: A cross-sectional, observational analytic study was conducted in 35 children NS with minimal change diseases from February to August 2019 in Haji Adam Malik General Hospital, Medan. Blood pressure was examined and serum Vitamin D levels along with serum creatinine, albumin, and calcium were measured. RESULTS: Of 35 children, 21 children (60%) had proteinuria. Regarding the category of Vitamin D status, there were 40% and 34.3% with deficiency and severe deficiency of Vitamin D, respectively. The median serum Vitamin D levels were not significantly different among the age group. Children with proteinuria showed lower serum Vitamin D levels (P &lt; 0.001). There was an elevation of systolic and diastolic blood pressure in children with proteinuria (P = 0.039 and P = 0.036, respectively). Our study showed a weak negative correlation between serum Vitamin D levels and either systolic or diastolic blood pressure (r-0.114 and r-0.174, respectively). CONCLUSION: Both Vitamin D deficiency and severe deficiency are common in children with NS. In this study, serum Vitamin D levels have been shown to have a weak negative correlation with blood pressure in children with NS.

Vitamin D deficiency is associated with orthostatic hypotension in older men: a cross-sectional analysis from the British Regional Heart Study.

Backgroundorthostatic hypotension (OH) that occurs within, or at, 1 minute of standing is associated with higher risk of falls, myocardial infarction, syncope and mortality, compared to OH that occurs after 1 minute of standing. Whether vitamin D deficiency increases the risk of OH is controversial.Methodsthis was a cross-sectional analysis of 3,620 older, community-dwelling men. Multinomial, multiple logistic regression models were used to calculate the risk of OH across categories of vitamin D status (deficient [<25 nmol/l], insufficient [≥25–<50 nmol/l] and sufficient [≥50 nmol/l]) and parathyroid hormone quintile.Resultsmen with vitamin D deficiency were more likely to have OH that occurred within 1 minute of standing in univariate logistic regression (OR 1.88, 95% CI 1.40–2.53) and multinomial, multiple logistic regression (OR 1.51, 95% CI 1.06–2.15), compared to men with sufficient levels of vitamin D. Vitamin D insufficiency was not associated with the risk of OH. Elevated parathyroid hormone was not associated with risk of OH.Conclusionthe absence of an association between vitamin D insufficiency and risk of OH and the presence of an association between vitamin D deficiency and risk of OH suggest that there may be a threshold effect; it is only below a particular level of vitamin D that risk of OH is increased. In this cohort, the threshold was <25 nmol/l. Future work should investigate whether treating vitamin D deficiency can improve postural blood pressure or if preventing vitamin D deficiency reduces the incidence of OH.

Evaluation of Self-Assessed State of Health and Vitamin D Knowledge in Emirati and International Female Students in United Arab Emirates (UAE).

IntroductionGlobally, vitamin D deficiency is one of the most common deficiencies, affecting nearly half the world’s population. The objective of this survey was to assess and compare the knowledge about vitamin D and the perceived state of health in Emirati and international tourist female students in Dubai, United Arab Emirates (UAE).MethodsThis is a cross-sectional study that took place in universities in Dubai, United Arab Emirates. This survey consisted of 17 multiple choice questions and was adapted from a study recently conducted in Poland. The first part of the survey assessed levels of supplementation, diet and UV exposure. Another section evaluated the participants’ self-assessed state of health in terms of vitamin D testing, symptoms related to vitamin D deficiency and general welbeing. The collected data were statistically analyzed using SPSS statistics for windows version 26.0 (SPSS Inc., Chicago, IL, United States). Statistical significance was set at P < 0.05.Results105 respondents were Emiratis and 65 were international students. The average age was 21, with an average BMI 23.3 kg/m2. Almost one-third of each group reported using Vitamin D supplements once weekly. The vast majority of both groups reported rarely getting tanned. Almost all participants in both groups reported regular consumption of Vitamin D rich foods. In both groups, more than half reported consuming milk and cheese regularly and up to one-third reported consuming fish in a regular manner. Although more than half of the students rated their health as good; more than two-thirds reported experiencing muscle pain; only half reported having their blood Vitamin D levels measured once; half reported experiencing problems with concentration and more than three-quarters reported experiencing bad mood in the past month. The prevalence of these symptoms was almost similar across different categories of vitamin D supplementation, tanning habits, dietary intake, or nationality. No statistically significant differences were noted between the Emirati and International tourist students regarding any of the studied variables.ConclusionNotably, more Emirati students were aware of the association between vitamin D and osteoporosis than International tourist students (40% vs. 21.9%, respectively; p < 0.05). On the other hand, both groups had lower knowledge about the relationship between vitamin D deficiency and depression, Rheumatoid Arthritis and Hypertension, and the optimal vitamin D level; however, no statistically significant differences were noted regarding this knowledge of Emiratis and international students.

Vitamin D and Reproductive Hormones Across the Menstrual Cycle.

How do the calciotropic hormones (25-hydroxyvitamin D, 1,25-dihydroxyvitamin D and intact parathyroid hormone (iPTH)) vary across the menstrual cycle and do cyclic patterns of reproductive hormones (estradiol, progesterone, LH, FSH) differ by vitamin D status? Calciotropic hormones vary minimally across the menstrual cycle; however, women with 25-hydroxyvitamin D below 30ng/ml have lower mean estradiol across the menstrual cycle. Prior human studies suggest that vitamin D status is associated with fecundability, but the mechanism is unknown. Exogenous estrogens and prolonged changes in endogenous estradiol (pregnancy or menopause) influence concentrations of 25-hydroxyvitamin D. In vitro, treatment with 1,25-dihydroxyvitamin D increases steroidogenesis in ovarian granulosa cells. There are little data about changes in calciotropic hormones across the menstrual cycle or cyclic patterns of reproductive hormones by categories of vitamin D status. A prospective cohort study of 89 self-identified white women aged 18-44, across two menstrual cycles. Participants were a subset of the BioCycle Study, a community-based study conducted at the University of Buffalo, 2005-2007. Eligible participants had self-reported regular menstrual cycles between 21 and 35days and were not using hormonal contraception or vitamins. Early morning fasting blood samples were drawn at up to eight study visits per cycle. Visits were timed to capture information in all cycle phases. Serum samples for 89 women (N= 163 menstrual cycles) were analyzed for estradiol, progesterone, LH, FSH and 25-hydroxyvitamin D (25(OH)D). Variability in calciotropic hormones within and across menstrual cycles was assessed using intraclass correlation coefficients and non-linear mixed models. Given the relative stability of the calciotropic hormones across the menstrual cycle, non-linear mixed models were used to examine differences in the cyclic patterns of estradiol, progesterone, LH and FSH by categories of each calciotropic hormone (split at the median). These models were conducted for all ovulatory cycles (N= 142 ovulatory menstrual cycles) and were adjusted for age, BMI (measured in clinic) and self-reported physical activity. Median 25(OH)D concentration was 29.5ng/ml (SD 8.4), and only 6% of women had vitamin D deficiency (<20ng/ml). The mean concentration of 25(OH)D did not differ between the luteal and follicular phase; however, both 1,25(OH)2D and iPTH showed small fluctuations across the menstrual cycle with the highest 1,25(OH)2D (and lowest iPTH) in the luteal phase. Compared with women who had mean 25(OH)D ≥30ng/ml, women with lower 25(OH)D had 13.8% lower mean estradiol (95% confidence interval: -22.0, -4.7) and 10.8% lower free estradiol (95% CI: -0.07, -0.004). Additionally, compared to women with iPTH ≤36pg/ml, women with higher concentrations of iPTH had 12.7% lower mean estradiol (95% CI: -18.7, -6.3) and 7.3% lower progesterone (95% CI: -13.3, -0.9). No differences in the cyclic pattern of any of the reproductive hormones were observed comparing cycles with higher and lower 1,25(OH)2D. Women included in this study had self-reported 'regular' menstrual cycles and very few were found to have 25(OH)D deficiency. This limits our ability to examine cycle characteristics, anovulation and the effects of concentrations of the calciotropic hormones found in deficient individuals. Additionally, the results may not be generalizable to women with irregular cycles, other races, or populations with a higher prevalence of vitamin D deficiency. These findings support current clinical practice that does not time testing for vitamin D deficiency to the menstrual cycle phase. We find that women with lower vitamin D status (lower 25(OH)D or higher iPTH) have lower mean concentrations of estradiol across the menstrual cycle. Although this study cannot identify a mechanism of action, further in vitro work or clinical trials may help elucidate the biologic mechanisms linking calciotropic and reproductive hormones. This work was supported by the Intramural Research Programs of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health (contract numbers: HHSN275200403394C, HHSN275201100002I and Task 1 HHSN27500001) and the National Institute of Environmental Health Sciences. There are no competing interests.

Prevalence of vitamin D deficiency and associated risk factors among adults in Chandigarh

Background: Vitamin D deficiency is a global health concern affecting individuals across all the age groups in both the genders. Aims and Objectives: The present study intends to assess the prevalence of Vitamin D deficiency and associated risk factors in adult males and females of Chandigarh. Materials and Methods: The sample included 332 males and 295 females of the age ranging between 30 and 70 years. Vitamin D level of all the participants was estimated by employing chemiluminescence immunoassay method. All the subjects were divided into three categories of Vitamin D level, i.e., normal range (>30–100 ng/ml), insufficiency (21–29 ng/ml), and deficiency (0–20 ng/ml) as per the Endocrine Society Guidelines (2011). Results: The overall prevalence of Vitamin D deficiency was found to be 28.5% in males and 63.4% in females of Chandigarh. The prevalence of Vitamin D deficiency exhibited an age-associated increment in both the males and females. Conclusion: Lesser physical activity and no intake of calcium, Vitamin D, and multivitamin supplements were possible determinants of Vitamin D deficiency.

Relationship Between Dietary Vitamin D and Deaths From Stroke and Coronary Heart Disease: The Japan Collaborative Cohort Study.

There is growing evidence about the importance of vitamin D for cardiovascular health. Therefore, we examined the relationship between dietary vitamin D intake and risk of mortality from stroke and coronary heart disease in Japanese population. A prospective study encompassing 58 646 healthy Japanese adults (23 099 men and 35 547 women) aged of 40 to 79 years in whom dietary vitamin D intake was determined via a self-administered food frequency questionnaire. The median follow-up period was 19.3 years (1989-2009). The hazard ratios and 95% confidence intervals of mortality were calculated using categories of vitamin D intake. During 965 970 person-years of follow-up, 1514 stroke and 702 coronary heart disease deaths were documented. Vitamin D intake was inversely associated with risk of mortality from total stroke especially intraparenchymal hemorrhage but not from coronary heart disease; the multivariable hazard ratios (95% confidence intervals) for the highest (≥440 IU/d) versus lowest (<110 IU/D) categories of vitamin D intake were 0.70 (0.54-0.91; P for trend=0.04) for total stroke and 0.66 (0.46-0.96; P for trend=0.04) for intraparenchymal hemorrhage. Dietary vitamin D intake seems to be inversely associated with mortality from stroke.

The Association of Vitamin D Status with Disease Activity in a Cohort of Crohn's Disease Patients in Canada.

We determined the association between vitamin D status as 25hydroxyvitamin D [25(OH)D] and disease activity in a cohort of 201 Crohn’s Disease (CD) patients in Saskatoon, Canada over three years. The association between high-sensitivity C-reactive protein (hs-CRP) and 25(OH)D and several disease predictors were evaluated by the generalized estimating equation (GEE) over three time-point measurements. A GEE binary logistic regression test was used to evaluate the association between vitamin D status and the Harvey-Bradshaw Index (HBI). The deficient vitamin D group (≤29 nmol/L) had significantly higher mean hs-CRP levels compared with the three other categories of vitamin D status (p < 0.05). CRP was significantly lower in all of the other groups compared with the vitamin D-deficient group, which had Coef. = 12.8 units lower (95% CI −19.8, −5.8), Coef. 7.85 units (95% CI −14.9, −0.7), Coef. 9.87 units (95% CI −17.6, −2.0) for the vitamin D insufficient, adequate, and optimal groups, respectively. The vitamin D status was associated with the HBI active disease category. However, the difference in the odds ratio compared with the reference category of deficient vitamin D category was only significant in the insufficient category (odds ratio = 3.45, p = 0.03, 95% CI 1.0, 10.8). Vitamin D status was inversely associated with indicators of disease activity in Crohn’s disease, particularly with the objective measures of inflammation.

The seasonal importance of serum 25-hydroxyvitamin D for bone mineral density in older women.

The impact of season when determining a serum 25-hydroxyvitamin D (S-25OHD) cut-off level for optimal bone health is unknown. To investigate the relative importance of S-25OHD for bone mineral density (BMD) by season. A subcohort of 5002 Swedish women (mean age 68 years), randomly selected from a large population-based longitudinal cohort study with repeat dietary and lifestyle information, was enrolled during 2003-2009 for a clinical examination, which included dual-energy X-ray absorptiometry and collection of fasting blood samples. Categories of vitamin D status were determined by S-25OHD (measured by HPLC-MS/MS). In samples collected during summer, we found a gradual increase in BMD of the total hip up to a S-25OHD level of 40 nmol L-1 (6% of the cohort). In women with S-25OHD concentrations below 30 nmol L-1 during summer, adjusted BMD was 11% lower [95% confidence interval (CI) 3-19] and in those with S-25OHD levels of 30-40 nmol L-1 BMD was 6% lower (95% CI 1-11), compared with women with S-25OHD levels above 80 nmol L-1 . Low S-25OHD concentrations during summer (<30 nmol L-1 ) were also associated with higher adjusted relative risk of osteoporosis (4.9; 95% CI 2.9-8.4) compared with concentrations above 80 nmol L-1 . By contrast, no differences in mean BMD values between categories of S-25OHD were found during winter. Summer concentrations of S-25OHD appear to be the most useful to predict BMD, whereas winter levels have limited value. To determine a S-25OHD cut-off level for vitamin D deficiency, it may be necessary to take into account the season of blood collection.

Calibration and seasonal adjustment for matched case-control studies of vitamin D and cancer.

Vitamin D measurements are influenced by seasonal variation and specific assay used. Motivated by multicenter studies of associations of vitamin D with cancer, we formulated an analytic framework for matched case-control data that accounts for seasonal variation and calibrates to a reference assay. Calibration data were obtained from controls sampled within decile strata of the uncalibrated vitamin D values. Seasonal sine-cosine series were fit to control data. Practical findings included the following: (1) failure to adjust for season and calibrate increased variance, bias, and mean square error and (2) analysis of continuous vitamin D requires a variance adjustment for variation in the calibration estimate. An advantage of the continuous linear risk model is that results are independent of the reference date for seasonal adjustment. (3) For categorical risk models, procedures based on categorizing the seasonally adjusted and calibrated vitamin D have near nominal operating characteristics; estimates of log odds ratios are not robust to choice of seasonal reference date, however. Thus, public health recommendations based on categories of vitamin D should also define the time of year to which they refer. This work supports the use of simple methods for calibration and seasonal adjustment and is informing analytic approaches for the multicenter Vitamin D Pooling Project for Breast and Colorectal Cancer. Published 2016. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Does vitamin D status track through adolescence?

Background: To our knowledge, no studies have reported on the long-term variability of vitamin D status in adolescents.Objective: To determine whether tracking of vitamin D status occurs in healthy adolescents, we assessed the variability of 25-hydroxyvitamin D [25(OH)D] every 2 y over a 10-y period in a longitudinal cohort of adolescents living in Johannesburg, South Africa (latitude 26°S).Design: Healthy adolescents who had blood samples available on ≥3 occasions between 11 and 20 y of age were included in the study. Of the cohort of 504 children, 99 met the criteria. The mean 25(OH)D concentration at each time point was measured, and the individual 25(OH)D z scores based on year 11 values were used as the reference. All 25(OH)D concentrations for a subject were measured in a single assay.Results: No significant correlation was found between 25(OH)D in the earlier and later years of adolescence, although significant correlations were found between year 11 and year 13 (r = 0.71, P < 0.0001) and between years 15, 17, and 20 (r ≥ 0.65, P < 0.0001). The percentage of adolescents whose 25(OH)D concentration changed by >20 nmol/L from year 11 was calculated for all age groups: 12% of the cohort had a change of >20 nmol/L at 13 y of age compared with 46% at 20 y of age. Just more than one-half (53%) of the cohort changed their category of vitamin D status between the ages of 11 and 20 y, and one-third of adolescents changed from being replete to insufficient over the same period.Conclusions: The data suggest that the measurement of 25(OH)D at a single time point does not reflect the long-term vitamin D status of an adolescent. These findings may cast doubt on the veracity of those studies that suggest an association of vitamin D status with various disease states in which vitamin D status was measured only once.

Commentary on the medico-legal aspects of prescribing vitamin D.

The medical and legal risks associated with prescribing unlicensed vitamin D products were recently highlighted in the article by Davies et al. 1. This prompted a letter from Rhein who raised the concern that this may dissuade practitioners from prescribing vitamin D 2, and exacerbate the failure to address adequately the widespread problem of vitamin D deficiency and insufficiency 3. Rhein asks whether European licensed preparations could be used in the absence of suitable or affordable UK licensed preparations, with appropriate checks. We address this point with a practical approach to understanding the licensed status of different preparations of vitamin D and the relevance with respect to prescribing and dispensing them, particularly with the recent licensing of vitamin D. We are not setting out to provide guidance on the specific requirements for vitamin D replacement in vitamin D deficiency and insufficiency, or advice on specific dosing regimens, or selection of specific vitamin D preparations, for which we encourage the reader to consult their local or national guidelines. However, when following such guidelines, the prescriber should be reasonably satisfied that the likely benefits of prescribing higher doses of vitamin D products exceed the likely risks of harm. For example, with respect to evidence of benefit in terms of mortality, the Cochrane Review on vitamin D supplementation for prevention of mortality in adults by Bjelakovic et al. 4 which included 32 trials of vitamin D3, found that a dose of vitamin D3 below 800 units a day significantly decreased mortality (RR 0.92, 95% CI 0.87, 0.97, P = 0.005, I2 = 0%). However, a dose of vitamin D3 ≥ 800 units a day had no significant effect on mortality (RR 0.96, 95% CI 0.92, 1.00, P = 0.07, I2 = 0%). No effect on mortality was found with vitamin D2. In this commentary we present the risks of different categories of vitamin D products, with respect to their licensed status, within the context of the medico-legal framework.