Vitamin D may not be a good marker of disease activity in Korean patients with systemic lupus erythematosus

Vitamin D is a pleiotrophic hormone with immunoregulatory properties. Low levels of vitamin D have been discovered in various autoimmune diseases. Here, we investigated serum vitamin D levels in Koreans with systemic lupus erythematosus (SLE) and examined whether levels correlate with disease activity of SLE. Blood samples were prospectively collected from patients with SLE (n = 104) and normal controls (NC, n = 49) during the spring from March to May 2008. The level of serum 25-hydroxyvitamin D (25(OH)D3) was measured by radioimmunoassay. The serum 25(OH)D3 levels of patients with SLE (42.49 ± 15.08 ng/ml) were significantly lower than NC (52.72 ± 15.19 ng/ml, P < 0.001). Additionally, 17 patients with SLE (16.3%) had vitamin D insufficiency, while two NC had vitamin D insufficiency (4.1%). The risk of vitamin D insufficiency was 4.6-fold increased in SLE (P = 0.032). The serum 25(OH)D3 levels, adjusted with BMI, were positively correlated only with hemoglobin (β = 0.256, P = 0.018) and serum complement 3 (β = 0.365, P = 0.002). Serum vitamin D levels were lower, and vitamin D insufficiency was more common in Korean patients with SLE, however, our study demonstrated that vitamin D levels might not be a good marker of disease activity.     

Serum and dietary vitamin D and cardiovascular disease risk in elderly men: a prospective cohort study

Background and aimRecent research suggests that low vitamin D may be associated with cardiovascular disease (CVD).Methods and resultsWe prospectively evaluated the association of dietary plus supplemental vitamin D intake and serum 25(OH) vitamin D with CVD incidence in the Osteoporotic Fractures in Men (MrOS) Study. Vitamin D intake was measured using a food frequency questionnaire and self-reported supplemental intake in 3094 men (mean age 76.4 years). From a subset of this population, we measured 25(OH) vitamin D in 813 men. Median 25(OH) vitamin D was 25.3 ng/mL. During a median follow-up of 4.4 years, there were 472 CVD cases, including 371 from coronary heart disease (CHD) and 101 from cerebrovascular attack (CVA). In the 25(OH) vitamin D sub-cohort, there were 140 cases of CVD including 115 from CHD and 25 from CVA. We used a Cox proportional hazards regression to calculate hazard ratios (HR) for CVD by vitamin D quartile. After adjusting for age, season, and standard CVD risk factors, the lowest quartile of 25(OH) vitamin D (HR, 1.18; 95% CI, 0.69–2.03) and vitamin D intake (HR, 0.76; 95% CI, 0.56–1.04) were not significantly associated with CVD incidence, compared to the highest vitamin D quartiles. When 25(OH) vitamin D was further analyzed by sufficiency (≥30 ng/mL), insufficiency (≥15–29.9 ng/mL), and deficiency (<15 ng/mL), vitamin D deficiency was not significantly associated with CVD incidence compared to sufficiency (HR 1.34; 95% CI 0.65–2.77).ConclusionVitamin D intake and serum 25(OH) vitamin D were not associated with CVD risk.     

Vitamin D and the elderly

This review summarizes current knowledge on vitamin D status in the elderly with special attention to definition and prevalence of vitamin D insufficiency and deficiency, relationships between vitamin D status and various diseases common in the elderly, and the effects of intervention with vitamin D or vitamin D and calcium. Individual vitamin D status is usually estimated by measuring plasma 25-hydroxyvitamin D (25OHD) levels. However, reference values from normal populations are not applicable for the definition of vitamin D insufficiency or deficiency. Instead vitamin D insufficiency is defined as the lowest threshold value for plasma 25OHD (around 50 nmol/l) that prevents secondary hyperparathyroidism, increased bone turnover, bone mineral loss, or seasonal variations in plasma PTH. Vitamin D deficiency is defined as values below 25 nmol/l. Using these definitions vitamin D deficiency is common among community-dwelling elderly in the developed countries at higher latitudes and very common among institutionalized elderly, geriatric patients and patients with hip fractures. Vitamin D deficiency is an established risk factor for osteoporosis, falls and fractures. Clinical trials have demonstrated that 800 IU (20 microg) per day of vitamin D in combination with 1200 mg calcium effectively reduces the risk of falls and fractures in institutionalized patients. Furthermore, 400 IU (10 microg) per day in combination with 1000 mg calcium or 100 000 IU orally every fourth month without calcium reduces fracture risk in individuals over 65 years of age living at home. Yearly injections of vitamin D seem to have no effect on fracture risk probably because of reduced bioavailability. Simulation studies suggest that fortification of food cannot provide sufficient vitamin D to the elderly without exceeding present conventional safety levels for children. A combination of fortification and individual supplementation is proposed. It is argued that all official programmes should be evaluated scientifically. Epidemiological studies suggest that vitamin D insufficiency is related to a number of other disorders frequently observed among the elderly, such as breast, prostate and colon cancers, type 2 diabetes, and cardiovascular disorders including hypertension. However, apart from hypertension, causality has not been established through randomized intervention studies. It seems that 800 IU (20 microg) vitamin D per day in combination with calcium reduces systolic blood pressure in elderly women.     

Vitamin D deficiency and secondary hyperparathyroidism in the elderly: consequences for bone loss and fractures and therapeutic implications

Vitamin D deficiency is common in the elderly, especially in the housebound and in geriatric patients. The establishment of strict diagnostic criteria is hampered by differences in assay methods for 25-hydroxyvitamin D. The synthesis of vitamin D3 in the skin under influence of UV light decreases with aging due to insufficient sunlight exposure, and a decreased functional capacity of the skin. The diet contains a minor part of the vitamin D requirement. Vitamin D deficiency in the elderly is less common in the United States than elsewhere due to the fortification of milk and use of supplements. Deficiency in vitamin D causes secondary hyperparathyroidism, high bone turnover, bone loss, mineralization defects, and hip and other fractures. Less certain consequences include myopathy and falls. A diet low in calcium may cause an increased turnover of vitamin D metabolites and thereby aggravate vitamin D deficiency. Prevention is feasible by UV light exposure, food fortification, and supplements. Vitamin D3 supplementation causes a decrease of the serum PTH concentration, a decrease of bone turnover, and an increase of bone mineral density. Vitamin D3 and calcium may decrease the incidence of hip and other peripheral fractures in nursing home residents. Vitamin D3 is recommended in housebound elderly, and it may be cost-effective in hip fracture prevention in selected risk groups.     

Hypovitaminosis D: a widespread epidemic

Vitamin D insufficiency is widespread, regardless of geographical location. It is particularly prevalent in the elderly and has far-ranging health consequences including: osteoporosis, falls, increased risk of cancer, and altered glucose and lipid metabolism. Increasing evidence strongly supports the benefits of vitamin D supplementation and also reveals that present recommendations are inadequate, especially for older individuals. Although additional studies are still needed to further optimize diagnostic and therapeutic approaches, physicians should consider prescribing cholecalciferol--at least 2000 international units (IU) per day--to all elderly patients. Oral cholecalciferol supplementation at that level is inexpensive, safe, and effective, and has great potential to improve the quality of life of the elderly.     

Limited availability of nutritional vitamin D causing inappropriate treatment of vitamin D deficiency rickets with a response resembling pseudohypoparathyroidism type II in a Japanese patient

Vitamin D deficiency rickets occasionally resembles pseudohypoparathyroidism type II (PHP type II) with respect to the response to exogenous PTH in the presence of hypocalcemia. We encountered a Japanese patient with stage 2 vitamin D deficiency rickets, who had increased urinary cAMP excretion and no response of urinary phosphate or N-acetyl-beta-D-glucosaminidase excretion to exogenous PTH under normocalcemic and normophosphatemic conditions, after treatment with 1,25(OH)2 vitamin D3. This case shows that it is possible for a response mimicking that of PHP type II to occur when the serum calcidiol level is low due to causes other than hypocalcemia and secondary hyperparathyroidism. When the serum calcidiol level is low, the appropriate treatment should be cholecalciferol or ergocalciferol. However, because neither is commercially available as a useful formulation in Japan, physicians are forced to inappropriately use calcitriol or analogs.     

Association of baseline vitamin D level with genetic determinants and virologic response in patients with chronic hepatitis B

Aim

The role of vitamin D in individuals with chronic hepatitis B (CHB) is unclear. We aimed to explore the association of baseline vitamin D level with genetic determinants and week‐104 treatment outcome in CHB patients.

Methods

Baseline serum 25‐hydroxycholecalciferol (25(OH)D) levels and genetic polymorphism within GC, DHCR7, and CYP2R1 were determined in stored serum of 560 patients who were enrolled into a multicenter, randomized, controlled study and completed 104 weeks of telbivudine monotherapy or telbivudine‐based optimized therapy. Virologic response was defined as hepatitis B virus DNA <300 copies/mL (52 IU/mL) at week 104.

Results

The mean 25(OH)D value was 29.64 ng/mL. The percentage of patients with vitamin D insufficiency (<30 ng/mL) and vitamin D deficiency (<20 ng/mL) were 55.0% and 20.9%, respectively. Gender, season, latitude, and GC rs2282679 polymorphism were independent factors of vitamin D status. Patients with sufficient vitamin D (≥30 ng/mL) achieved a higher virologic response rate than those with vitamin D insufficiency (81.7% vs. 67.2%, P < 0.001). The area under the curve of 25(OH)D to predict virologic response was 0.65 (P < 0.001; 95% confidence interval, 0.62–0.67). On multivariate analysis, 25(OH)D level was an independent predictor of virologic response, but not associated with hepatitis B envelope antigen (HBeAg) seroconversion or alanine aminotransferase (ALT) normalization.

Conclusions

Vitamin D insufficiency was highly prevalent in treatment‐naïve CHB patients in mainland China. Latitude and genetic determinants affect vitamin D status. Baseline vitamin D level can predict week‐104 virologic response, but not HBeAg seroconversion or ALT normalization.     

Calcium metabolism in the frail elderly

Elderly residents of aged care facilities are usually considered at high risk of osteoporosis not only due to their age, but also due to nutritional factors, poor sunlight exposure and renal insufficiency. This study aimed to describe calcium metabolism and related hormones in this high-risk population. A total of 1280 elderly residents of hostels and nursing homes in the northern Sydney area (aged 65 years or over) had serum analysis for clinical chemistry including serum 25-hydroxy vitamin D (25OHD) and parathyroid hormone (PTH). Moderate renal impairment (creatinine clearance 30–60 ml/min) was common (62%), but hypocalcaemia was uncommon (7.0%). Mild hypoalbuminaemia was common (34% below 40 g/l, but only 3.2% below 35 g/l); 77.5% of the cohort had low serum 25OHD levels (<39 nmol/l) and 41.7% had elevated PTH levels (>66 pg/ml). Independent predictors of low serum 25OHD levels included gender, age, serum PTH, season, mobility and creatinine clearance. Use of vitamin D supplementation conferred modestly higher serum 25OHD levels (45.5 vs 27.1 nmol/l in non-supplemented residents, p<0.0001) and lower PTH levels (50.0 vs 78.1 pg/ml, p<0.0001). Despite adequate overall nutrition, vitamin D deficiency is present in the majority of this population. Vitamin D deficiency remains a significant public health problem in the institutionalized frail elderly. Currently available supplements are not adequate or utilized frequently enough to address this problem.     

A randomized controlled trial of the effects of vitamin D on muscle strength and mobility in older women with vitamin D insufficiency

OBJECTIVES: To evaluate the effects of vitamin D treatment on muscle strength and mobility in older women with vitamin D insufficiency. DESIGN: One‐year population‐based, double‐blind, randomized, controlled trial. SETTING: Perth, Australia (latitude 32°S). PARTICIPANTS: Three hundred two community‐dwelling ambulant elderly women aged 70 to 90 with a serum 25‐hydroxyvitamin D (25(OH)D) concentration less than 24 ng/mL. INTERVENTION: Vitamin D₂ 1,000 IU/d or identical placebo; calcium citrate (1 g calcium/d) in both groups. MEASUREMENTS: Lower limb muscle strength and mobility as assessed using the Timed Up and Go Test (TUAG). RESULTS: At baseline, mean±standard deviation serum 25(OH)D was 17.7±4.2 ng/mL; this increased to 24.0±5.6 ng/mL in the vitamin D group after 1 year but remained the same in the placebo group. For hip extensor and adductor strength and TUAG, but not for other muscle groups, a significant interaction between treatment group and baseline values was noted. In those with baseline values in the lowest tertile, vitamin D improved muscle strength and TUAG more than calcium alone (mean (standard error): hip extensors 22.6% (9.5%); hip adductors 13.5% (6.7%), TUAG 17.5% (7.6%), P<.05). Baseline 25(OH)D levels did not influence patient response to supplementation. CONCLUSION: Vitamin D therapy was observed to increase muscle function in those who were the weakest and slowest at baseline. Vitamin D should be given to people with insufficiency or deficiency to improve muscle strength and mobility.     

Bone disease in vitamin D-deficient patients with Crohn's disease

Vitamin D deficiency is frequently observed in patients with Crohn's disease and may be associated with an increased risk of development of metabolic bone disease. To estimate the incidence of metabolic bone disease by noninvasive methods, 31 patients (17–75 years old) with Crohn's disease and low 25-hydroxy vitamin D (25-OHD) levels in winter were investigated in the following summer by measuring the bone mineral content (BMC) of the distal radius by single photon absorptiometry and the cortical area ratio (CAR) calculated from radiographs of the right hand and by x-ray of the lumbar spine. Forty-five percent of the patients showed signs of metabolic bone disease. BMC and CAR correlated with 25-OHD serum levels (P<0.05), especially in men. Furthermore, the amount of sun exposure has an influence not only on 25-OHD serum levels both in summer and in winter (P=0.0006), but also on the BMC (P=0.07). Consequently, vitamin D deficiency is of major importance for the development of metabolic bone disease in patients with Crohn's disease. Vitamin D deficiency can be prevented by increasing sun exposure and long-term vitamin D supplementation.     

Effect of vitamin D on insulin sensitivity in elderly patients with impaired fasting glucose

Aim: Recent data has shown that vitamin D increases insulin sensitivity; however, there is little evidence about the effects of this treatment on elderly people with impaired fasting glucose. The aim of the present study was to investigate the effect of vitamin D treatment on insulin sensitivity and metabolic parameters in elderly people with impaired fasting glucose. Methods: A total of 28 elderly patients were enrolled into the vitamin D treatment group. The control group included 23 age‐, sex‐ and body mass index‐matched elderly participants. The vitamin D treatment group was treated with vitamin D₃ according to serum concentrations of 25(OH)D. Results: With supplementation, 96.0% of patients achieved a mean serum 25(OH)D concentration of 123.2 ± 59.9 nmol/L. After 4.7 ± 2.5 months of treatment, there was a significant decrease in homeostasis model assessment of insulin resistance, insulin and glucose concentrations in the vitamin D treatment group (P = 0.007, P = 0.007, P = 0.037, respectively). Vitamin D treatment significantly increased high‐density lipoprotein cholesterol (P = 0.037), but did not cause statistically significant differences in other lipid parameters. Conclusion: We found that vitamin D treatment might modify insulin sensitivity in the elderly with impaired fasting glucose. Geriatr Gerontol Int 2012; 12: 454–460.     

Calcium and vitamin D: Skeletal and extraskeletal health

Vitamin D is known for its role in calcium homeostasis for optimal skeletal health. It was previously believed that only elderly or hospitalized patients were at risk for vitamin D insufficiency, but many people in the general US population have insufficient levels of 25-hydroxyvitamin D (25[OH]D). According to the Third National Health and Nutrition Examination Survey, 61% of white and 91% of black Americans suffer from vitamin D insufficiency (25[OH]D < 32 ng/mL). Recent studies have demonstrated that a minimum 25(OH)D level of 32 ng/mL is necessary for optimal protection from fracture and intestinal absorption of calcium. Recently, vitamin D has been recognized as important for extraskeletal functions such as immune function, cancer prevention, and hypertension prevention. We review the role of vitamin D in skeletal health and present data on vitamin D in other extraskeletal diseases, with special emphasis on the rheumatology patient.     

Update on vitamin D and evaluation of vitamin D status

Knowledge about vitamin D has greatly improved during the last few years. Vitamin D cannot any more be considered as exclusively necessary to prevent ricket/osteomalacia. Its role in the prevention of some osteoporotic fractures in the elderly (in association with calcium nutrition) is now well demonstrated and many epidemiologic and laboratory data argue for a role in the prevention of several diseases or anomalies (cancer, auto-immune diseases, cardiovascular events, sarcopenia...). A few intervention studies confirming some of these effects also exist. Vitamin D status can easily be assessed by measuring serum 25 hydroxy vitamin D (25OHD) level. However, many experts have claimed that the population-based reference values for 25OHD are too low and that the cut-off value below which vitamin D insufficiency can be present is somewhere between 20 and 40 ng/mL with a clear tendency to target values above 30 ng/mL (75 nmol/L). The main consequences are that vitamin D insufficiency is highly frequent whereas the currently recommended supplementation doses are not sufficient.     

Vitamin D, K and bone mineral density

Both vitamin D and vitamin K are essential nutrients for bone health. It is believed that vitamin D deficiency is responsible for rickets in infants and osteomalacia in adults, and chronic vitamin D insufficiency induces hyperparathyroidism and reduces bone mineral density, resulting in an increased risk of osteoporosis. Vitamin K deficiency is thought to cause impaired activation of bone matrix protein osteocalcin, and reduction of osteoblast function, resulting in impaired bone formation. Recently, we reported that a high prevalence of low vitamin D status (low serum 25-hydroxyvitamin D concentration) . low bone mineral density, and a high prevalence of low vitamin K status (high serum undercarboxylated osteocalcin concentration) . high frequency of bone fracture in elderly women in Japan. However, no correlation between low vitamin K status and low bone mineral density was observed in this subjects.     

Vitamin D,race, and experimental pain sensitivity in older adults with knee osteoarthritis

Objective

Low circulating serum levels of 25‐hydroxyvitamin D (referred to hereafter as vitamin D) have been correlated with many health conditions, including chronic pain. Recent clinical practice guidelines define vitamin D levels <20 ng/ml as deficient and levels of 21–29 ng/ml as insufficient. Vitamin D insufficiency, including the most severe levels of deficiency, is more prevalent in black Americans. Ethnic and race group differences have been reported in both clinical and experimental pain, with black Americans reporting increased pain. The purpose of this study was to examine whether variations in vitamin D levels contribute to race differences in knee osteoarthritis pain.

Methods

The sample consisted of 94 participants (74% women), including 45 blacks and 49 whites with symptomatic knee osteoarthritis. Their average age was 55.8 years (range 45–71 years). Participants completed a questionnaire on knee osteoarthritis symptoms and underwent quantitative sensory testing, including measures of sensitivity to heat‐induced and mechanically induced pain.

Results

Blacks had significantly lower levels of vitamin D compared to whites, demonstrated greater clinical pain, and showed greater sensitivity to heat‐induced and mechanically induced pain. Low levels of vitamin D predicted increased experimental pain sensitivity, but did not predict self‐reported clinical pain. Group differences in vitamin D levels significantly predicted group differences in heat pain and pressure pain thresholds at the index knee and ipsilateral forearm.

Conclusion

These data demonstrate that race differences in experimental pain are mediated by differences in the vitamin D level. Vitamin D deficiency may be a risk factor for increased knee osteoarthritis pain in black Americans.

     

Association of 25‐hydroxyvitamin D with prevalent osteoarthritis of the hip in elderly men: The osteoporotic fractures in men study

Objective

To examine the cross‐sectional association of serum levels of 25‐hydroxyvitamin D, or 25(OH)D, with prevalent radiographic hip osteoarthritis (OA) in elderly men.

Methods

In a cohort of 1,104 elderly men from the Osteoporotic Fractures in Men Study, 25(OH)D serum levels were determined by mass spectrometry, followed by pelvic radiographs ∼4.6 years later. Categories of vitamin D levels were defined as follows: deficiency as ≤15 ng/ml, insufficiency as 15.1–30 ng/ml, and sufficiency as >30 ng/ml. Radiographs were assessed for severity of hip OA using a summary grade of 0–4 for individual features of hip OA. Logistic regression was used to assess associations of serum 25(OH)D levels with prevalent radiographic hip OA; covariates included age, clinic site, season at the time of blood withdrawal, self‐reported hip pain for >30 days, timed 6‐meter walk, presence of at least 1 coexisting condition, and self‐rated health status.

Results

Men with radiographic hip OA had a slower 6‐meter walking time (P < 0.0001), reported more hip pain (P = 0.0001), had a lower vitamin D level (P = 0.0002), and had a higher prevalence of vitamin D insufficiency (P = 0.002) and vitamin D deficiency (P = 0.012) compared with controls. Higher 25(OH)D levels were associated with a lower prevalence of radiographic hip OA (odds ratio [OR] 1.39 per 1 SD decrease in 25[OH]D, 95% confidence interval [95% CI] 1.11–1.74) after adjusting for age, season, and clinic site. Men with vitamin D insufficiency had an increased likelihood of prevalent radiographic hip OA (OR 2.19, 95% CI 1.21–3.97) compared with men with sufficient levels of 25(OH)D, and in men with vitamin D deficiency, there was a tendency toward an increased likelihood of radiographic hip OA (OR 1.99, 95% CI 0.83–4.74).

Conclusion

Men with vitamin D deficiencies are twice as likely to have prevalent radiographic hip OA, and therefore vitamin D therapy to augment skeletal health in the elderly is warranted.

     

Vitamin D Levels,Lung Function and Steroid Response in Adult Asthma

Journal. American Review of Respiratory Critical Care Med 2010 Jan14 epub ahead of print. Rationale. Individuals with asthma have a differential response to inhaled corticosteroids. Vitamin D is postulated to effect the response to gluocorticoids in asthma. The authors’ objective was to determine the effects of vitamin D on the asthma phenotype and response to oral corticosteroids. Methods. Non smoking adults with asthma were enrolled to assess the association between serum 25(OH)(vitamin D) concentrations and pulmonary function, airway hyper responsiveness (AHR) and glucocorticoid response as determined by dexamethasone induced expression of MAP kinase phosphatase-1 (MKP-1) by peripheral blood mononuclear cells. Results. 54 adult asthmatics (FEVI OF 83% ± 16%predicted, serum vitamin D level of 28 ± 10 ng/ml) were enrolled. Elevated vitamin D levels were related to increased pulmonary function, with a 21 ± 9ml increase in FEVI for each ng/ml increase in vitamin D (p = 0.03,r = 0.8). Enrollees with vitamin D insufficiency (<30ng/ml) demonstrated elevated AHR with a PC20 FEVI of 1.03 ± 0.2mg/ml compared with 1.92 ± 0.2 in subjects with vitamin D ≥30ng/ml (p = 0.01). Those participants not on inhaled corticosteroid therapy had a dexamethasone induced MAP kinase phosphatase 1 expression that was enhanced with higher vitamin D levels with a 0.05 ± 0.02 fold enhancement (p = 0.02,r = 0.5) in MKP-1 expression documented with each ng/ml enhancement in vitamin D. There was an inverse correlation between BMI and vitamin D with a decrease of 0.58 ± ng/ml in serum vitamin D for each unit increment in BMI (P = 0.002, R = O.4). This inverse correlation continued to be significant only in asthmatics that were not currently on inhaled corticosteroids (p = 0.009, r = 0.6). These findings were noted in the absence of a significant enhancement of IL-10 expression or mitogenic cell proliferation. Author's conclusions. Decreased vitamin D levels in asthma are related to impairment in pulmonary function, enhancement of airway hyper responsiveness and decline in glucocorticoid response unrelated to IL10. These findings suggest that supplementation with vitamin D in individuals with asthma may ameliorate multiple characteristics of asthma severity and therapeutic responsiveness. Reviewer's conclusions. Further large prospective randomized studies are needed to confirm the findings of the authors that vitamin D levels in asthma are related to pulmonary function parameters and glucocorticoid responsiveness and therefore supplementation with vitamin D may be therapeutic in asthma.     

The necessity and safety of calcium and vitamin D in the elderly

The necessity and safety of an oral calcium (Ca) and vitamin D regimen was evaluated in a population of 66 independently living and 73 institutionalized elderly women over an 11-week winter period. The members of both groups were randomly assigned into trial and control groups. Serum Ca, creatinine, and calcidiol levels were measured before and after the trial. The regimen consisted of 1.558 g of Ca and 45 micrograms (equal to 1,800 IU) of vitamin D administered daily in addition to the normal diet. The controls received no treatment. A majority of the elderly subjects living independently had ensured their Ca, and a quarter of them also their vitamin D intake on their own initiative. The mean serum calcidiol concentration before the trial was 24.1 nmol/L in the institutionalized and 38.5 nmol/L in the elderly subjects living independently (P less than .001). After the trial, serum calcidiol was 10.4 nmol/L in the institutionalized control subjects and had decreased (P less than .001) in both control groups, but increased (P less than .001) in both treatment groups. The safety indicators, serum Ca, creatinine, and calcidiol, did not indicate any group or individual side effect.     

Vitamin D and primary hyperparathyroidism (PHPT)

Vitamin D deficiency and primary hyperparathyroidism (PHPT) are two common conditions, especially in postmenopausal women. Vitamin D deficiency is said to be even more frequent in PHPT patients than in the general population due to an accelerated conversion of 25-hydroxy vitamin D (25OHD) into calcitriol or 24-hydroxylated compounds. Although several studies have reported worsening of PHPT phenotype (larger tumours, higher parathyroid hormone [PTH] levels, more severe bone disease) when vitamin D deficiency coexists whereas vitamin D supplementation in PHPT patients with a serum calcium level less than 3 mmol/L has been shown to be safe (no increase in serum or urinary calcium) and to decrease serum PTH concentration, many physicians are afraid to give vitamin D to already hypercalcemic PHPT patients. It is possible that, in some patients, a persistent vitamin D deficiency induces, in the long-term, an autonomous secretion of PTH (i.e. tertiary hyperparathyroidism). The mechanism by which this could occur is unclear however. Finally, as many, otherwise normal, subjects with vitamin D insufficiency may have an increased serum PTH level we believe that those with vitamin D insufficiency should be excluded from a reference population for serum PTH levels. By doing that, we found that the upper normal limit for serum PTH was 25-30% lower than in the whole population.     

Vitamin D deficiency and adult asthma exacerbations

Objectives: There is growing evidence indicating a connection between vitamin D deficiency and the severity of asthma exacerbations. This study seeks to assess the relationship between vitamin D deficiency and the number and severity of asthma exacerbation in adults. Methods: A retrospective analysis was conducted in 92 patients being treated for asthma at the University of New Mexico Adult Asthma Clinic. Serum 25-hydroxyvitamin D3 levels were analyzed in adults with mild to severe persistent asthma. Using multi-variant modeling, the relationship was examined between serum vitamin D levels and the odds of asthma exacerbations ranging in severity from moderate to severe over the span of five years. Results: This study demonstrates that vitamin D sufficiency was significantly associated with a decreased total number of asthma exacerbations (incidence rate ratio [IRR]: 0.61, 95% confidence interval [CI]: 0.44–0.84, p?=?0.002), decreased total severe asthma exacerbations (IRR: 0.41, 95% CI: 0.24–0.72, p?=?0.002) and decreased emergency room visits (IRR: 0.42, 95% CI: 0.20–0.88, p?=?0.023). Conclusion: Vitamin D deficiency may be linked to the risk of severe asthma exacerbations in adults.