Vitamin D deficiency

High prevalence of hypovitaminosis D and secondary hyperparathyroidism in elders living in nonprofit homes in South Brazil

OBJECTIVES

Hypovitaminosis D (HD) and secondary hyperparathyroidism (SHP) are common in elders, and many factors could contribute to them. The objectives of this study were to estimate the prevalence of HD, SHP, and its associated factors, in individuals living in nonprofit homes for elders in south Brazil. Design Cross-sectional study.

METHODS

Serum 25-hydroxyvitamin D 25(OH)D, intact parathyroid hormone (PTH), total calcium, phosphorus, alkaline phosphatase, magnesium, creatinine, and albumin levels were measured in late spring, November, 2005. The presence of factors potentially related with HD and SHP-age, sex, weight, height, skin phototype, sun exposure, exercise, smoking, use of < or = 5 medications or diuretics or alcohol, and daily calcium ingestion.

RESULTS

102 subjects age 77.8 +/- 9.0 were included in the study. HD was found in 85.7% and SHP in 53% of the subjects. The estimated daily calcium ingestion was 720 mg. There was no association between serum 25(OH)D levels and any of the risk factors evaluated. Serum 25(OH)D levels were correlated with serum PTH (r = -0.358, P = 0.000), calcium (r = 0.306, P = 0.002), and albumin (r = 0.253, P = 0.011) levels. In univariate analysis, SHP was positively associated with age (P = 0.006), and female sex (0.007); and negatively associated with sunlight exposure (P = 0.020), GFR (P = 0.000), Ln25(OH)D (P = 0.002), and total serum calcium (P = 0.024). After multivariate model adjustment, age [OR 1.09 (CI 1.01-1.18); P = 0.024], Ln25(OH)D [OR 0.92 (CI 0.08-0.74); P = 0.013], GFR [OR 0.96 (CI 0.92-0.99); P = 0.013], and hydrochlorothiazide treatment [OR 7.63 (CI 1.67-34.9); P = 0.008] were independently associated with SHP.

CONCLUSIONS

HD and SHP are highly prevalent in elders living in old-age homes. No associations were established between common risk factors and low serum levels of 25(OH)D levels; however, SHP was independently related with age, 25(OH)D, GFR, and hydrochlorothiazide use.

Vitamin D deficiency and risk of cardiovascular disease

BACKGROUND

Vitamin D receptors have a broad tissue distribution that includes vascular smooth muscle, endothelium, and cardiomyocytes. A growing body of evidence suggests that vitamin D deficiency may adversely affect the cardiovascular system, but data from longitudinal studies are lacking.

METHODS AND RESULTS

We studied 1739 Framingham Offspring Study participants (mean age 59 years; 55% women; all white) without prior cardiovascular disease. Vitamin D status was assessed by measuring 25-dihydroxyvitamin D (25-OH D) levels. Prespecified thresholds were used to characterize varying degrees of 25-OH D deficiency (< 15 ng/mL, < 10 ng/mL). Multivariable Cox regression models were adjusted for conventional risk factors. Overall, 28% of individuals had levels < 15 ng/mL, and 9% had levels < 10 ng/mL. During a mean follow-up of 5.4 years, 120 individuals developed a first cardiovascular event. Individuals with 25-OH D < 15 ng/mL had a multivariable-adjusted hazard ratio of 1.62 (95% confidence interval 1.11 to 2.36, P=0.01) for incident cardiovascular events compared with those with 25-OH D > or = 15 ng/mL. This effect was evident in participants with hypertension (hazard ratio 2.13, 95% confidence interval 1.30 to 3.48) but not in those without hypertension (hazard ratio 1.04, 95% confidence interval 0.55 to 1.96). There was a graded increase in cardiovascular risk across categories of 25-OH D, with multivariable-adjusted hazard ratios of 1.53 (95% confidence interval 1.00 to 2.36) for levels 10 to < 15 ng/mL and 1.80 (95% confidence interval 1.05 to 3.08) for levels < 10 ng/mL (P for linear trend=0.01). Further adjustment for C-reactive protein, physical activity, or vitamin use did not affect the findings.

CONCLUSIONS

Vitamin D deficiency is associated with incident cardiovascular disease. Further clinical and experimental studies may be warranted to determine whether correction of vitamin D deficiency could contribute to the prevention of cardiovascular disease.

Relationships of low serum vitamin D3 with anthropometry and markers of the metabolic syndrome and diabetes in overweight and obesity

Low serum 25 hydroxyvitamin D₃ (vitamin D₃) is known to perturb cellular function in many tissues, including the endocrine pancreas, which are involved in obesity and type II diabetes mellitus (TIIDM). Vitamin D₃ insufficiency has been linked to obesity, whether obesity is assessed by body mass index (BMI) or waist circumference (waist). Central obesity, using waist as the surrogate, is associated with the metabolic syndrome (MetSyn), insulin resistance, TIIDM and atherosclerotic cardiovascular disease (CVD). We tested how vitamin D₃ was related to measures of fat mass, MetSyn markers, haemoglobin A_1c (HbA_1c) and MetSyn in a cross-sectional sample of 250 overweight and obese adults of different ethnicities. There were modest inverse associations of vitamin D₃ with body weight (weight) (r = -0.21, p = 0.0009), BMI (r = -0.18, p = 0.005), waist (r = -0.14, p = 0.03), [but not body fat % (r = -0.08, p = 0.24)], and HbA_1c (r = -0.16, p = 0.01). Multivariable regression carried out separately for BMI and waist showed a decrease of 0.74 nmol/L (p = 0.002) in vitamin D₃ per 1 kg/m² increase in BMI and a decrease of 0.29 nmol/L (p = 0.01) per 1 cm increase in waist, with each explaining approximately 3% of the variation in vitamin D₃ over and above gender, age, ethnicity and season.

The similar relationships of BMI and waist with vitamin D₃ may have been due to associations between BMI and waist, or coincidental, where different mechanisms relating hypovitaminosis D₃ to obesity occur concurrently. Previously reviewed mechanisms include that 1) low vitamin D₃, may impair insulin action, glucose metabolism and various other metabolic processes in adipose and lean tissue 2) fat soluble-vitamin D₃ is sequestered in the large adipose compartment, and low in serum, 3) obese people may be sensitive about their body shape, minimising their skin exposure to view and sunlight (not tested). We showed evidence for the first theory but no evidence to support the second.

In the current study, serum vitamin D₃ was inversely related to weight, BMI and markers of TIIDM (large waist, raised HbA_1c) but not to adipose mass nor to MetSyn per se.

Vitamin D insufficiency among African-Americans in the southeastern United States: implications for cancer disparities (United States)

OBJECTIVE

To determine the prevalence and predictors of vitamin D insufficiency among black and white adult residents of the southern US.

METHODS

A cross-sectional analysis of serum 25(OH)D levels using baseline blood samples from 395 Southern Community Cohort Study (SCCS) participants. Participants were African-American and white adults aged 40-79 who enrolled in the study from 2002-2004. We defined hypovitaminosis D as serum 25(OH)D levels < or = 15 ng/ml.

RESULTS

Hypovitaminosis D prevalence was 45% among blacks and 11% among whites. Vitamin D intake from diet and supplements was associated with modest increases in circulating 25(OH)D (0.5-0.7 ng/ml per 100 IU increment), but hypovitaminosis D was found for 32% of blacks with intake > or = 400 IU/day. Body mass index (BMI) was a strong predictor of risk for hypovitaminosis D among black women (OR = 6.5, 95% CI 1.7-25.1 for BMI > or = 30 kg/m(2) vs. 18-24.9 kg/m(2)). UVR exposure estimated by residential location was positively associated with 25(OH)D levels among all groups except white women.

CONCLUSIONS

Hypovitaminosis D was present in a substantial proportion of the African-American population studied, even in the South and among those meeting recommended dietary guidelines. Vitamin D should continue to be a studied target for ameliorating racial cancer disparities in the US.

Measurement of 25-hydroxyvitamin D3 (25OHD3) and 25-hydroxyvitamin D2 (25OHD2) in human serum using liquid chromatography-tandem mass spectrometry and its comparison to a radioimmunoassay method

BACKGROUND

Measurement of vitamin D molecules are important in the management of patients with bone disease. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to measure 25OHD(3) and 25OHD(2) in human serum and compared it to the traditionally used DiaSorin radioimmunoassay (RIA).

METHODS

Serum samples (200 microl) were treated with acetonitrile and centrifuged to remove protein. An online solid-phase extraction procedure was used. Calibration solutions (5-100 ng/ml) of 25OHD(2) and 25OHD(3) were prepared using 4% albumin in phosphate-buffered saline. Chromatography: C18 column, isocratic ethanol/water (83/17, v/v). Mass spectrometry system: atmospheric pressure chemical ionization in the positive ion mode. Transitions: 25OHD(3), m/z 401.4-->383.4; 25OHD(2), m/z 413.4-->395.4; and the internal standard hexadeuterated-25OHD(3), m/z 407.7-->389.7.

RESULTS

Detection limits were 0.49 ng/ml (25OHD(3)) and 1.86 ng/ml (25OHD(2)). Intra- and inter-assay coefficients of variation (CV) were <7% and <11%, respectively, for 25OHD(3) and <9% and <16%, respectively, for 25OHD(2). Recovery averaged (SD) 99% (2%) for 25OHD(3) and 95% (0.8%) for 25OHD(2). In a method comparison of 551 specimens from the National Health and Nutrition Examination Survey, the LC-MS/MS method gave values that were on average 13% higher (95%CI: 11-15%) than RIA results.

CONCLUSIONS

This high throughput candidate reference method requires minimal sample preparation and is suitable for routine use for analysis of vitamin D status.

Approach to the prostate cancer patient with bone disease

Prostate cancer is the most common visceral malignancy in men. Androgen deprivation therapy (ADT) is commonly used in patients with nonmetastatic prostate cancer and is associated with significant bone loss and fractures. The greatest bone loss occurs during initiation of ADT. Men should have assessment of skeletal integrity with bone mineral density examination by dual x-ray absorptiometry of the hip and spine. Men with fragility fractures or osteoporosis by bone density should be considered for bisphosphonate therapy. Men with low bone mass may need antiresorptive therapy, depending on other risk factors. Men with a normal bone mineral density should be followed up closely with bone densitometry while on ADT. All men should receive preventive measures with calcium (1200 mg daily in divided doses), vitamin D (800-1000 IU/d), and weight-bearing exercise. Men should be evaluated for additional secondary causes of bone loss including vitamin D insufficiency. Guidelines are needed for androgen-induced bone loss screening and treatment.

Renal cell carcinoma in a child presented as bilateral femur neck fractures caused by severe vitamin D deficiency

An Ethiopian girl 14 years and 11 months of age presented with bilateral transcervical hip fractures. Workup revealed severe vitamins D and C deficiencies with secondary hyperparathyroidism. Imaging studies showed bilateral radiolucent metaphyseal bands with multiple lytic lesions in long bones. A mass in the right flank was found to be renal cell carcinoma (RCC). Currently, 9 months postsurgery and supplemental therapy, the patient is fully ambulatory and free of pain. This first report of asymptomatic RCC in severely vitamin D deficient child highlights the relation of RCC to vitamin D deficiency and emphasizes the importance of careful evaluation of these children.

Zoledronic acid and clinical fractures and mortality after hip fracture

BACKGROUND

Mortality is increased after a hip fracture, and strategies that improve outcomes are needed.

METHODS

In this randomized, double-blind, placebo-controlled trial, 1065 patients were assigned to receive yearly intravenous zoledronic acid (at a dose of 5 mg), and 1062 patients were assigned to receive placebo. The infusions were first administered within 90 days after surgical repair of a hip fracture. All patients (mean age, 74.5 years) received supplemental vitamin D and calcium. The median follow-up was 1.9 years. The primary end point was a new clinical fracture.

RESULTS

The rates of any new clinical fracture were 8.6% in the zoledronic acid group and 13.9% in the placebo group, a 35% risk reduction with zoledronic acid (P=0.001); the respective rates of a new clinical vertebral fracture were 1.7% and 3.8% (P=0.02), and the respective rates of new nonvertebral fractures were 7.6% and 10.7% (P=0.03). In the safety analysis, 101 of 1054 patients in the zoledronic acid group (9.6%) and 141 of 1057 patients in the placebo group (13.3%) died, a reduction of 28% in deaths from any cause in the zoledronic acid group (P=0.01). The most frequent adverse events in patients receiving zoledronic acid were pyrexia, myalgia, and bone and musculoskeletal pain. No cases of osteonecrosis of the jaw were reported, and no adverse effects on the healing of fractures were noted. The rates of renal and cardiovascular adverse events, including atrial fibrillation and stroke, were similar in the two groups.

CONCLUSIONS

An annual infusion of zoledronic acid within 90 days after repair of a low-trauma hip fracture was associated with a reduction in the rate of new clinical fractures and with improved survival. (ClinicalTrials.gov number, NCT00046254 [ClinicalTrials.gov].).

Is vitamin D deficiency to blame for the asthma epidemic?

In the 1960s, the prevalence of asthma and allergic diseases began to increase worldwide. Currently, the burden of the disease is more than 300 million people affected. We hypothesize that as populations grow more prosperous, more time is spent indoors, and there is less exposure to sunlight, leading to decreased cutaneous vitamin D production. Coupled with inadequate intake from foods and supplements, this then leads to vitamin D deficiency, particularly in pregnant women, resulting in more asthma and allergy in their offspring. Vitamin D has been linked to immune system and lung development in utero, and our epidemiologic studies show that higher vitamin D intake by pregnant mothers reduces asthma risk by as much as 40% in children 3 to 5 years old. Vitamin D deficiency has been associated with obesity, African American race (particularly in urban, inner-city settings), and recent immigrants to westernized countries, thus reflecting the epidemiologic patterns observed in the asthma epidemic. Providing adequate vitamin D supplementation in pregnancy may lead to significant decreases in asthma incidence in young children.

Autism and vitamin D

Any theory of autism's etiology must take into account its strong genetic basis while explaining its striking epidemiology. The apparent increase in the prevalence of autism over the last 20 years corresponds with increasing medical advice to avoid the sun, advice that has probably lowered vitamin D levels and would theoretically greatly lower activated vitamin D (calcitriol) levels in developing brains. Animal data has repeatedly shown that severe vitamin D deficiency during gestation dysregulates dozens of proteins involved in brain development and leads to rat pups with increased brain size and enlarged ventricles, abnormalities similar to those found in autistic children. Children with the Williams Syndrome, who can have greatly elevated calcitriol levels in early infancy, usually have phenotypes that are the opposite of autism. Children with vitamin D deficient rickets have several autistic markers that apparently disappear with high-dose vitamin D treatment. Estrogen and testosterone have very different effects on calcitriol's metabolism, differences that may explain the striking male/female sex ratios in autism. Calcitriol down-regulates production of inflammatory cytokines in the brain, cytokines that have been associated with autism. Consumption of vitamin D containing fish during pregnancy reduces autistic symptoms in offspring. Autism is more common in areas of impaired UVB penetration such as poleward latitudes, urban areas, areas with high air pollution, and areas of high precipitation. Autism is more common in dark-skinned persons and severe maternal vitamin D deficiency is exceptionally common the dark-skinned.

CONCLUSION

simple Gaussian distributions of the enzyme that activates neural calcitriol combined with widespread gestational and/or early childhood vitamin D deficiency may explain both the genetics and epidemiology of autism. If so, much of the disease is iatrogenic, brought on by medical advice to avoid the sun. Several types of studies could easily test the theory.

Activated vitamin D attenuates left ventricular abnormalities induced by dietary sodium in Dahl salt-sensitive animals

Observations in hemodialysis patients suggest a survival advantage associated with activated vitamin D therapy. Left ventricular (LV) structural and functional abnormalities are strongly linked with hemodialysis mortality. Here, we investigated whether paricalcitol (PC, 19-nor-1,25(OH)(2)D(2)), an activated vitamin D compound, attenuates the development of LV abnormalities in the Dahl salt-sensitive (DSS) rat and whether humans demonstrate comparable findings. Compared with DSS rats fed a high-salt (HS) diet (6% NaCl for 6 weeks), HS+PC was associated with lower heart and lung weights, reduced LV mass, posterior wall thickness and end diastolic pressures, and increased fractional shortening. Blood pressures did not significantly differ between the HS groups. Plasma brain natriuretic peptide levels, and cardiac mRNA expression of brain natriuretic peptide, atrial natriuretic factor, and renin were significantly reduced in the HS+PC animals. Microarray analyses revealed 45 specific HS genes modified by PC. In a retrospective pilot study of hemodialysis patients, PC-treated subjects demonstrated improved diastolic function and a reduction in LV septal and posterior wall thickness by echocardiography compared with untreated patients. In summary, PC attenuates the development of LV alterations in DSS rats, and these effects should be examined in human clinical trials.

Colon cancer: prognosis for different latitudes, age groups and seasons in Norway

The survival of colon cancer patients in Norway, as determined three years after diagnosis, is dependent on the season of diagnosis. This has been attributed to seasonal variations of the vitamin D status. Since solar radiation and food are the human sources of vitamin D, we divided Norway in three regions: The southeast region with a high annual dose of ultraviolet (UV) to the population, as evidenced by a high incidence rate of squamous cell carcinoma of the skin (SCC), the midwest region and the north region with low annual UV doses. The latter region is characterized by a high consumption of vitamin D, mainly through fish intake. Vacations to southern latitudes were equally frequent for all the three geographical regions. Two age groups were analyzed separately (< or =65 years and >65 years), since the photosynthesis of vitamin D(3) in skin decreases with age. In all three regions, and in both age groups, the survival was highest for summer and autumn diagnosis. The seasonal effect was slightly, but not significantly, better for the younger than for the older age group. The effect was similar for all three geographical regions, irrespective of SCC incidence.