High parathyroid hormone,but not low vitamin D concentrations,expose elderly inpatients to hypertension

Aim: Serum parathyroid hormone (PTH) and 25‐hydroxyvitamin D (25OHD) concentrations might contribute to blood pressure (BP) levels. Mixed results in previous literature could be due to the failure to consider both these hormones concurrently, despite their long‐known relationship. Our objective was to examine the association of serum intact PTH and 25OHD concentrations with BP levels amongst older inpatients, while accounting for each other. Methods: The participants were 284 Caucasian older inpatients with no suspicion of primary hyperparathyroidism (mean age 85.87 ± 5.90 years; 65.8% female) admitted to the geriatric acute care unit of Angers University Hospital, France. They were divided into two groups according to the existence of hypertension (i.e. systolic blood pressure [SBP] >140 mmHg, or diastolic blood pressure [DBP] >90 mmHg). Age, sex, numbers of chronic diseases and of drugs taken daily, use of antihypertensive or corticosteroid drugs and of calcium supplements/vitamin D, thyroid‐stimulating hormone and albumin concentrations, creatinine clearance, and season tested were used as covariables. Results: Hypertensive participants (n = 106) had higher intact PTH concentrations than normotensive patients (P = 0.044). There was a positive linear association of BP with intact PTH concentrations (adjusted β = 0.08, P = 0.015 for SBP; adjusted β = 0.05, P = 0.044 for DBP), but not with vitamin D. Serum intact PTH concentration, unlike 25OHD, was associated with hypertension (adjusted OR 1.01, P = 0.038). Conclusions: Irrespective of 25OHD, PTH was associated with hypertension by increasing both SBP and DBP. Geriatr Gerontol 2013; 13: 783–791 .     

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.     

Vitamin D insufficiency and hyperparathyroidism in a low income, multiracial, elderly population

This report examines the wintertime vitamin D and PTH status of 308 participants in the Boston Low Income Elderly Osteoporosis Study of noninstitutionalized low income elderly men and women (age, 64-100 yr) living in subsidized housing in Boston, MA. Twenty-one percent of the 136 black subjects and 11% of the 110 whites had very low plasma 25-hydroxyvitamin D (25OHD) concentrations (<25 nmol/L), and 73% of the blacks and 35% of the whites had 25OHD concentrations less than 50 nmol/L. The mean 25OHD levels of the smaller Hispanic and Asian subsets were generally similar to those of the white subjects. In addition to race, significant predictors of 25OHD included vitamin D intake (positive association) and smoking (inverse association), but not sex or age. Low 25OHD concentrations were associated with increased PTH and reduced serum calcium. The PTH level in the black subjects was substantially higher than that in the white subjects, and this difference was only partially explained by the racial difference in 25OHD. Elderly individuals who live in northern areas, particularly African-Americans, should be strongly encouraged to increase their vitamin D intake, especially in winter.     

Serum parathyroid hormone predicts time to fall independent of vitamin D status in a frail elderly population

Very frail older people constitute an increasing proportion of ageing populations and often have vitamin D deficiency. Falls are frequent in this population and have usually been associated with vitamin D deficiency. In this prospective study we measured serum 25-hydroxyvitamin D (25OHD), serum PTH, and falls in 637 ambulatory subjects living in institutional aged care facilities (intermediate-care hostels or nursing homes). The study sample comprised 121 men (mean age, 82.1 yr) and 516 women (mean age, 86.7 yr). Two hundred and seventy-four subjects fell one or more times over a mean duration of follow-up of 10.2 months. Vitamin D deficiency, defined as a serum 25OHD level below 39 nmol/liter was present in 73.6%. Baseline serum 25OHD and PTH were significantly associated with falls in univariate analyses. In multivariate analyses that also corrected for balance and health status, PTH remained a significant predictor of falls independent of 25OHD. Serum PTH is a predictor of time to first fall in the frail elderly independent of vitamin D status and measures of general health.     

A global study of vitamin D status and parathyroid function in postmenopausal women with osteoporosis: baseline data from the multiple outcomes of raloxifene evaluation clinical trial

Vitamin D deficiency leads to secondary hyperparathyroidism, increased bone turnover, and bone loss and, when severe, to osteomalacia. Vitamin D deficiency is common in elderly people, especially the institutionalized. The definition of vitamin D deficiency is hampered by the fact that large interlaboratory differences exist in assays for serum 25-hydroxyvitamin D (25OHD), the main circulating metabolite. The international Multiple Outcomes of Raloxifene Evaluation study, a large prospective intervention trial in postmenopausal women with osteoporosis, offered the opportunity to compare vitamin D status and parathyroid function throughout many countries over the world. For this study, baseline data were available from 7564 postmenopausal women from 25 countries on 5 continents. All women had osteoporosis, i.e. bone mineral density (BMD) at femoral neck or lumbar spine was lower than t-score -2.5, or they had 2 vertebral fractures. Serum 25OHD was measured by RIA, and serum PTH was measured by immunoradiometric assay. BMD was measured by dual x-ray absorptiometry. The mean (+/-SD) serum 25OHD was 70.8 +/- 30.9 nmol/L. A low serum 25OHD (<25 nmol/L) was observed in 4.1% of all women in the Multiple Outcomes of Raloxifene Evaluation study, ranging from 0% in south east Asia (very few patients) to 8.3% in southern Europe. Serum 25OHD was between 25-50 nmol/L in 24.3% of the women. Serum 25OHD showed a significant seasonal relationship, with lower values in all regions in winter. Serum PTH correlated negatively with serum 25OHD (r = -0.25; P < 0.001). This significant negative correlation was observed in all regions. When serum 25OHD was less than 25, 25-50, or more than 50 nmol/L, respectively, mean serum PTH levels were 4.8, 4.1, and 3.5 pmol/L, respectively (by ANOVA, P < 0.001). Similarly, mean alkaline phosphatase levels were 83.7, 79.1, and 75.7 U/L (P < 0.001), respectively, with increasing serum 25OHD. The effect of serum 25OHD on BMD was only significant for the BMD of the trochanter where a serum 25OHD level less than 25 nmol/L was associated with a 4% lower BMD. After 6 months of treatment with vitamin D(3) (400-600 IU/day) and calcium (500 mg/day), serum 25OHD increased from 70.8 +/- 29.8 to 92.3 +/- 28.6 nmol/L. Serum PTH decreased significantly after 6 months of treatment, and this decrease depended on baseline serum 25OHD. When baseline serum 25OHD was less than 25, 25-50, or more than 50 nmol/L, respectively, serum PTH decreased by 0.8, 0.5, or 0.2 pmol/L, respectively (P < 0.001). In conclusion, serum 25OHD was less than 25 nmol/L in 4% of the women, and this was associated with a 30% higher serum PTH. In 24% of the women serum 25OHD was between 25-50 nmol/L, associated with a 15% higher level of serum PTH compared with women with a serum 25OHD greater than 50 nmol/L. A low serum 25OHD level was also associated with higher serum alkaline phosphatase and lower BMD of the trochanter. Treatment with vitamin D(3) and calcium increased serum 25OHD and decreased serum PTH significantly; the effect was greater for lower baseline serum 25OHD.     

Vitamin D supplementation in postmenopausal black women

Black women have lower levels of serum 25-hydroxyvitamin D (25OHD) with higher serum PTH levels than white women. Correction of these alterations in the vitamin D-endocrine system could lead to less bone loss in postmenopausal women and, consequently, preservation of bone mass. Ten healthy postmenopausal black women were given 20 microg vitamin D3 daily for 3 months. At the end of the study, mean serum 25OHD levels had increased from 24 to 63 nmol/L. Serum intact PTH and nephrogenous cAMP declined significantly, and there was a 21% drop in the fasting urinary N-telopeptide of type I collagen. Vitamin D3 supplementation raises serum 25OHD levels in postmenopausal black women, decreases secondary hyperparathyroidism, and reduces bone turnover. These findings should spur further investigation of the use of vitamin D supplementation in the prevention of osteoporosis in this population.     

Hypovitaminosis D in female patients with chronic low back pain

Chronic low back pain (LBP) is an extremely common problem in practice, where it is often labeled idiopathic. No sufficient studies have been conducted to analyze the contribution of hypovitaminosis D to the etiology of chronic LBP in populations wherein vitamin D deficiency is endemic. The present study was, therefore, carried out to examine hypovitaminosis D and its determinants in female patients with chronic LBP during the childbearing period. Sixty female patients complaining of LBP lasting more than 3 months were clinically studied rheumatologically and neurologically. Questionnaires and indices quantifying risk factors associated with vitamin D deficiency were utilized. Biochemical assays of serum calcium, phosphorus, alkaline phosphatase (ALP), parathormone (PTH), and 25-hydroxyvitamin D (25 OHD) were performed and compared to those of 20 matched healthy controls. The determinants of vitamin D levels in patients were examined by stepwise regression. Patients with LBP had significantly lower 25 OHD levels (p < 0.05) and significantly higher PTH (p < 0.05) and ALP (p < 0.001) than controls, although there were no significant group differences in calcium and phosphorus. Hypovitaminosis D (25 OHD < 40 ng/ml) was found in 49/60 patients (81%) and 12/20 (60%) of controls, with an odds ratio of 2.97. Although many risk factors related to sun exposure, clothing, diet, and pregnancy were significantly correlated with vitamin D levels in patients, only limited duration of sun exposure, contributing 55% to the variance of 25 OHD, limited areas of skin exposed (13%), and increased number of pregnancies (2%), were significant determinants of vitamin D levels in patients. Despite the sunny climate, hypovitaminosis D is prevalent among Egyptian women in the childbearing period, especially those presenting with chronic LBP, where it is associated with hyperphosphatasia and hyperparathyroidism, without alterations in serum calcium. The major determinant of hypovitaminosis D in our patients is limited sun exposure.     

The effect of a combined oral calcium and vitamin D supplement for treating mild to moderate vitamin D deficiency in postmenopausal women

Objective

To evaluate the efficacy of a combined calcium and vitamin D (Ca-D3) supplement for vitamin D deficiency in a small group of postmenopausal women.

Methods

A prospective open label 3 month-study.

Participants

23 postmenopausal women (mean age 61.2 yrs) with vitamin D deficiency were given a combined oral Ca-D3 supplement called “Osteoblast”. The supplement comprises 500 mg elemental calcium and 500 IU of cholecalciferol. The dosing regimen comprised a loading dose of 1000 IU of cholecalciferol per day for one month (two tablets) and thereafter a maintenance dose of 500 IU of cholecalciferol per day for 2 months (one tablet).

Outcome measure

Serum was collected for calcium, 25 hydroxyvitamin D3 (25OHD3), and PTH measurements, as well as early morning 2-hour urine calcium/creatinine excretion index (Uca/creat). Specimens were collected at baseline and after 3 months of therapy. Data are reported as mean ± 1 standard error and 95% confidence intervals.

Results

Data was available for the 21 subjects who completed the study. Two subjects (9%) withdrew because of gastrointestinal intolerance. There were 3 subjects with moderate (12.5–24 nmol/L) and 18 with mild (25–49 nmol/L) vitamin D deficiency. Ten subjects (48%) had secondary hyperparathyroidism. Following the oral Ca-D3 combination, serum 25OHD3 levels normalised in all subjects with 18 (86%) subjects achieving values of greater than 70 nmol/L. Serum 25OHD3 levels increased from 36 (31–41) to 91 (79–102) nmol/L (p = 0.0001), increasing by an average of 152% over the 3-month period. There was a corresponding 38% decrease in serum PTH concentrations at 3 months (5.1 + 0.6 pmol/L), compared with baseline (8.0 + 1 pmol/L) (p = 0.001). No subject developed hypercalcemia, but an elevated Uca/creat excretion index occurred in one subjects.

Conclusions

A combined oral Ca-D3 product (Osteoblast) is effective for treating vitamin D deficiency and is adequately tolerated.     

Vitamin D status and PTH in young men: a cross‐sectional study on associations with bone mineral density,body composition and glucose metabolism

Objective Although vitamin D and bone metabolism are closely related, few studies have addressed the effects of vitamin D status on bone in men at time of peak bone mass. The objectives of this study were to evaluate the prevalence of vitamin D inadequacy in a cross‐sectional study in young men and the effects of vitamin D and parathyroid hormone (PTH) on bone mass, bone markers and metabolic function. Design and Participants The study population consisted of 783 men aged 20–29 years. Measurements Bone mineral density (BMD) of the total hip, femoral neck and lumbar spine was measured. dual‐energy X‐ray absorptiometry was used to evaluate total body fat mass (BFAT). Visceral fat mass and abdominal subcutaneous fat mass (ViFM and ScFM) were assessed using magnetic resonance imaging. A radioimmunoassay was used to measure the level of 25‐hydroxy vitamin D (25OHD). Results The prevalence of vitamin deficiency (serum 25OHD < 50 nm ) was 6·3% during summer and 43·6% during winter. Serum 25OHD was associated with BMD at all sites and inversely associated with bone‐specific alkaline phosphatase and directly with carboxyterminal telopeptide of type‐1‐collagen. 25OHD and PTH were inversely associated with BFAT, whereas 25OHD also was inversely associated with body mass index, waist–hip ratio, ViFM and ScFM after adjustment for confounders. The associations were found only to be present in participants with insufficient levels of 25OHD. 25‐Hydroxy vitamin D and PTH were inversely related to insulin resistance in vitamin‐insufficient participants only. No associations between PTH or 25OHD and blood pressure were noted. Conclusion The study showed a high prevalence of 25OHD deficiency in young, northern European men, which was significantly associated with decreased BMD. PTH and 25OHD were found to be inversely related to the markers of insulin resistance.     

Vitamin D status and redefining serum parathyroid hormone reference range in the elderly.

Subclinical vitamin D insufficiency is characterized by mild secondary hyperparathyroidism and enhanced risk of osteoporotic fracture. However, although low levels of 25-hydroxyvitamin D (25OHD) are common in otherwise normal elderly people, vitamin D status has not generally been taken into account in the previously published reference values for serum PTH. We measured fasting morning serum (obtained from April through June) PTH, total calcium, albumin, phosphate, creatinine, bone markers, and 25OHD in 280 healthy subjects (140 men and 140 women), aged 60-79 yr. Serum PTH was measured by means of 2 immunoradiometric assays, the Allegro intact PTH assay (Nichols Institute Diagnostics) and the new CAP assay (Scantibodies Laboratory, Inc.). We found a high prevalence (167 of 280; 59.6%) of low 25OHD (< or =30 nmol/L) in these otherwise healthy individuals. The PTH concentrations (95% confidence interval) obtained in the whole group of 280 subjects ranged from 13-64 ng/L for the Allegro assay and from 10-44 ng/L for the CAP assay. In the subjects with a serum 25OHD concentration greater than 30 nmol/L, values for both PTH assays were lower, 10-46 and 9-34 ng/L for the Allegro and the CAP assays, respectively. By using these values as a reference range, approximately 25% of the subjects with a serum 25OHD level of 30 nmol/L or less had a high serum PTH level (whatever the assay), reflecting secondary hyperparathyroidism. This might be missed if the reference PTH values are those obtained in the entire group, as is usually done. These results strongly suggest that vitamin D status should be taken into account when establishing reference values for serum PTH in elderly subjects.     

Effects of vitamin D supplementation on strength, physical function, and health perception in older, community-dwelling men

OBJECTIVES: To study the effects of vitamin D supplementation in healthier populations of men. DESIGN: : Randomized, controlled trial. SETTING: General clinical research center. PARTICIPANTS: Sixty-five healthy, community-dwelling men (mean age+/-standard deviation=76+/-4, range 65-87). INTERVENTION: Cholecalciferol (1,000 IU/d) or placebo supplementation for 6 months; all received 500 mg supplemental calcium. MEASUREMENTS: Upper and lower extremity muscle strength and power, physical performance and activity, health perception, calcium and vitamin D intake, and biochemical assessment, including 25-hydroxyvitamin D (25OHD), parathyroid hormone (PTH), and ionized calcium levels. RESULTS: The levels of 25OHD increased and PTH decreased in the cholecalciferol group, whereas there were no significant changes in the control group (P<.001). Baseline 25OHD levels correlated with baseline single-leg stance time and physical activity score. Baseline PTH levels correlated with baseline 8-foot walk time and physical activity score. No significant difference in strength, power, physical performance, or health perception was found between groups. CONCLUSION: The 25OHD or PTH levels correlated with physical activity and physical performance in older, community-dwelling men with normal 25OHD status. Vitamin D supplementation increased 25OHD levels and decreased PTH levels but did not increase muscle strength or improve physical performance or health perception in this group of healthy, older men. Further investigations of the effects of vitamin D supplementation should focus on individuals with low levels of vitamin D.     

血清维生素D水平与骨代谢状态的相关性：附1389例观察

目的探讨上海地区人群血清25羟化维生素D水平与甲状旁腺激素及骨代谢指标的关系。方法应用自动电子发光免疫法检测健康成人血清25羟化维生素D（250HD）、甲状旁腺素（PTH）、骨代谢指标（骨钙素：BGP;I型原胶原N端前肽：PINP;β—I型胶原C端肽：β—CTX）。按血清250HD不同水平将受试者分为维生素D极低组、维生素D严重低下组、维生素D低下组、维生素D中间水平组和维生素D高分位5组,比较血清250HD与甲状旁腺激素及骨代谢的关系。结果接受检测的1389位受试者年龄为22～88岁,平均年龄（65．8±10．9）岁。男性552名,女性837名,按血清250HD水平分为5组：极低组≤4ng/mL,120例（8．6％）;严重低下组4．1—10ng／mL,232例（16．7％）;低下组10．1～20ng／mL,744例（53．5％）;中间水平组20．1～30ng／mL,206例（14．8％）;高分位组≥30．1ng／mL,87例（6．3％）。检测结果显示,血清PTH水平随250HD升高逐渐降低,呈负相关。血清PTH定值（cut—offvalue）的平台期在250HD16～20ng／mL之间出现。BGP和PINP在极低组和严重低下组明显增高,差异行统计学意义。矫正PTH后,250HD与BGP、PINP仍呈负相关。BGP平台期在250HD18～25ng／mL之间出现,PINP平台期在250HD20～25ng／mL之间出现。各组间BcTx差异无统计学意义。结论血清250HD≤10ng／mL时,骨形成标志物发生明显变化,血清250HD是影响骨代谢调节因子之一,但作为单个因子,其影响力度相对较弱。     

Relationships with serum parathyroid hormone in old institutionalized subjects

OBJECTIVE AND BACKGROUND: Old people in residential care are at the highest risk of any group for hip fracture. This may relate to their high prevalence of hyperparathyroidism. There are few data, however, on relationships with serum parathyroid hormone (PTH) in these individuals. This study therefore examined complex associations with serum PTH in nursing home and hostel residents. DESIGN: Cross-sectional analysis. PATIENTS: One hundred and forty-three nursing home and hostel residents of median age 84 years. MEASUREMENTS: Serum PTH, 25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D (1,25-(OH)2D), plasma creatinine, phosphate, calcium, albumin, Bsm-1 vitamin D receptor genotype, age, weight and use of frusemide or thiazide. RESULTS: The statistical models determined accounted for half the interindividual variation in serum PTH. Heavier weight was associated with both the prevalence of secondary hyperparathyroidism and the serum concentration of PTH. Novel interactions with serum PTH were identified between: weight and 25OHD; 25OHD and phosphate; and phosphate and thiazide diuretic use. Plasma phosphate was associated with PTH independently of calcium and 1,25-(OH)2D. There was no independent association between PTH and nuclear vitamin D receptor genotype. CONCLUSIONS: Heavier weight is associated with both the prevalence and severity of secondary hyperparathyroidism and consistent with animal models of secondary hyperparathyroidism, phosphate may relate to serum PTH independently of 1,25-(OH)2D or calcium.     

Relationship between the vitamin D content of maternal milk and the vitamin D status of nursing women and breast-fed infants

This work was designed to study the effect of the vitamin D content of human milk on the vitamin D status of exclusively breast-fed infants, and the relation between milk and maternal serum concentrations of vitamin D during the first month of lactation. Serum levels of calcium (Ca), phosphorus (P), magnesium (Mg) and 25-hydroxyvitamin D (25-OH-D) were determined in a racially heterogeneous population of nursing women, between days 3 and 5 (L3), 15 and 18 (L15) and 30 and 45 (L30) post partum. The same parameters were determined in the serum of 1-month-old breast-fed infants. Maternal milk samples were obtained at L3, L15 and L30 and analysed for Ca, P, Mg, vitamin D and 25-OH-D content. Milk levels of Ca, P and Mg were found to be within the range previously described by other authors. No correlation was found between serum and milk levels of vitamin D and 25-OH-D in nursing mothers. The 25-OH-D concentration in milk was related to its vitamin D content and strongly correlated (P less than 0.001) with the 25-OH-D levels in the serum of exclusively breast-fed infants. No significant changes were observed in maternal serum levels of 1,25-dihydroxyvitamin D (1,25-(OH)2D3) measured at L3 and L30, or between maternal and infant levels of 1,25-(OH)2D3 at L30. This study emphasizes the importance of the 25-OH-D content of maternal milk, in being primarily responsible for the vitamin D concentrations found in the serum of exclusively breast-fed infants.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vitamin D status and related parameters in a healthy population: the effects of age, sex, and season

The effects of age, sex, renal function, and seasonal variation on serum parameters within the vitamin D endocrine system were studied cross-sectionally in a healthy population of 167 men and 114 women, aged 20-94 yr. Serum 25-hydroxy- and 1,25-dihydroxyvitamin D [25OHD and 1,25-(OH)2D] did not decline with age in either sex. Nonlinear regression using a sine function showed a significant seasonal variation in 25OHD and 1,25-(OH)2D in both sexes (P less than 0.005). Serum intact PTH increased significantly by 35% over the age span in both sexes (P less than 0.005). In women, serum phosphorus and total and ionized calcium remained constant with age. In sharp contrast, males had a marked 25% fall in phosphorus across the age span (r = -0.564; P less than 0.0001) and a slight but significant 4% decline in total and ionized calcium. Creatinine clearance declined markedly with age, but was not related to 1,25-(OH)2D in either sex. Only in men was there a significant but modest inverse relationship between creatinine clearance and PTH (r = -0.212; P less than 0.05), which was multicollinear with age. We conclude that in healthy individuals 1) compromised vitamin D status or serum 1,25-(OH)2D levels are not a normal concomitant of aging; 2) declining glomerular filtration does not appear to be the principle cause of the age-related rise in PTH; and 3) there are marked male-female differences in phosphorus metabolism across the age span.     

Influence of vitamin D on parathyroid function in the elderly.

The effect of age and vitamin D status on parathyroid function was studied in 129 healthy subjects between 20 and 89 yr old, with normal serum creatinine (less than 0.11 mmol/L), and living in Cordoba, Spain. Serum calcium and phosphorus as well as 25-hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D [1,25-(OH)2D] decreased, whereas serum alkaline phosphatase increased, with age. Serum PTH also increased significantly with age when measured with either a carboxyl-terminal (cPTH) or an intact [PTH(1-84)] assay. The increase in cPTH, however, exceeded largely the increase in PTH(1-84) (+120% and +30% in subjects above 80 yr vs. young adults, respectively). Serum PTH(1-84) was negatively correlated with serum (ionized) calcium, 25OHD, and insulin-like growth factor I (IGF-I) but not with serum 1,25-(OH)2D. Serum 1,25-(OH)2D decreased with age and was highly correlated with serum 25OHD, cPTH, and IGF-I. In multiple regression analysis 50-60% of the variation of total and free 1,25-(OH)2D could be explained by serum 25OHD, PTH(1-84), and especially IGF-I, suggesting a possible role of decreasing GH and IGF-I concentrations in the mineral homeostasis of the elderly. Calcium infusion (1.5 mg/kg body weight over 10 min) decreased serum PTH(1-84) to below normal concentrations in young adults (nadir 14% of basal concentration), whereas the nadir in elderly subjects with secondary hyperparathyroidism was only 32% of basal concentration. The relative decrease was, however, identical in both age groups when simultaneous changes in ionized calcium were taken into account. Basal serum PTH(1-84) in selected elderly subjects (50 +/- 10 ng/L or 5 +/- 1 pmol/L, n = 10) decreased significantly (2.7 +/- 0.9 pmol/L, P less than 0.01) after 3 iv injections of 1,25-(OH)2D during 1 week without changes in serum (ionized) calcium. The PTH suppressibility after calcium infusion did not further improve. In conclusion: elderly patients with normal serum creatinine had a small (+30%) but significant increase in intact serum PTH concentration but the mean concentration still remained within the normal range. The PTH secretion remained normally suppressible by acute calcium infusion. Treatment with 1,25-(OH)2D decreased basal calcium-PTH setpoint without further additional effects during calcium infusion.     

Serum vitamin D2 and vitamin D3 metabolite concentrations and absorption of vitamin D2 in elderly subjects

The serum vitamin D2 and vitamin D3 metabolite concentrations and intestinal absorption of vitamin D2 were determined in healthy ambulatory and chronically institutionalized elderly subjects with normal renal function. The 25-hydroxyvitamin D (25OHD) concentrations were normal in all subjects (range, 8-43 ng/ml), although institutionalized subjects had a significantly lower mean value [19.2 +/- 2 (+/- SEM) ng/ml; P less than 0.01] compared with ambulatory subjects (25.3 +/- 2 ng/ml). All but one ambulatory subject had 25OHD3 as the major circulating form, whereas 25OHD2 was the major circulating metabolite in one third of the institutionalized subjects. The mean 1,25-dihydroxyvitamin D [1,25-(OH)2D] concentration in both groups was normal, but nine subjects had levels at or below the lower limit of normal despite normal 25OHD concentrations. Separate assay of 1,25-(OH)2D2 and 1,25(OH)2D3 revealed proportional distributions similar to those for 25OHD2 and 25OHD3. To study the effect of age on the intestinal absorption of vitamin D, we compared serum vitamin D2 concentrations after oral administration of 50,000 IU vitamin D2 in both healthy vitamin D-sufficient elderly subjects and young adults. We found no evidence of malabsorption of vitamin D in the elderly subjects. In summary, elderly subjects in New York, whether institutionalized or not, have normal serum 25OHD concentrations. However, while most elderly subjects have normal serum 1,25-(OH)2D levels, a significant proportion fail to produce normal concentrations of 1,25-(OH)2D, possibly due to age-related disturbances in renal synthesis of the hormone.     

Effects of a short-term vitamin D(3) and calcium supplementation on blood pressure and parathyroid hormone levels in elderly women

Calcium supplementation is effective in reducing blood pressure in various states of hypertension, including pregnancy-induced hypertension and preeclampsia. In addition, calcitropic hormones are associated with blood pressure. The hypothesis is that short-term therapy with calcium and vitamin D(3) may improve blood pressure as well as secondary hyperparathyroidism more effectively than calcium monotherapy. The effects of 8 weeks of supplementation with vitamin D(3) (cholecalciferol) and calcium on blood pressure and biochemical measures of bone metabolism were studied. The sample consisted of 148 women (mean +/- SD age, 74 +/- 1 yr) with a 25-hydroxycholecalciferol (25OHD(3)) level below 50 nmol/L. They received either 1200 mg calcium plus 800 IU vitamin D(3) or 1200 mg calcium/day. We measured intact PTH, 25OHD(3), 1,25-dihydroxyvitamin D(3), blood pressure, and heart rate before and after treatment. Compared with calcium, supplementation with vitamin D(3) and calcium resulted in an increase in serum 25OHD(3) of 72% (P < 0.01), a decrease in serum PTH of 17% (P = 0.04), a decrease in systolic blood pressure (SBP) of 9.3% (P = 0.02), and a decrease in heart rate of 5.4% (P = 0.02). Sixty subjects (81%) in the vitamin D(3) and calcium group compared with 35 (47%) subjects in the calcium group showed a decrease in SBP of 5 mm Hg or more (P = 0.04). No statistically significant difference was observed in the diastolic blood pressures of the calcium-treated and calcium- plus vitamin D(3)-treated groups (P = 0.10). Pearson coefficients of correlation between the change in PTH and the change in SBP were 0.49 (P < 0.01) for the vitamin D(3) plus calcium group and 0.23 (P < 0.01) for the calcium group. A short-term supplementation with vitamin D(3) and calcium is more effective in reducing SBP than calcium alone. Inadequate vitamin D(3) and calcium intake could play a contributory role in the pathogenesis and progression of hypertension and cardiovascular disease in elderly women.     

Association between vitamin D status and physical performance: the InCHIANTI study

BACKGROUND: Vitamin D status has been hypothesized to play a role in musculoskeletal function. Using data from the InCHIANTI study, we examined the association between vitamin D status and physical performance. METHODS: A representative sample of 976 persons aged 65 years or older at study baseline were included. Physical performance was assessed using a short physical performance battery (SPPB) and handgrip strength. Multiple linear regression was used to examine the association between vitamin D (serum 25OHD), parathyroid hormone (PTH), and physical performance adjusting for sociodemographic variables, behavioral characteristics, body mass index, season, cognition, health conditions, creatinine, hemoglobin, and albumin. RESULTS: Approximately 28.8% of women and 13.6% of men had vitamin D levels indicative of deficiency (serum 25OHD < 25.0 nmol/L) and 74.9% of women and 51.0% of men had vitamin D levels indicative of vitamin D insufficiency (serum 25OHD < 50.0 nmol/L). Vitamin D levels were significantly associated with SPPB score in men (beta coefficient [standard error (SE)]: 0.38 [0.18], p =.04) and handgrip strength in men (2.44 [0.84], p =.004) and women (1.33 [0.53], p =.01). Men and women with serum 25OHD < 25.0 nmol/L had significantly lower SPPB scores whereas those with serum 25OHD < 50 nmol/L had significantly lower handgrip strength than those with serum 25OHD > or =25 and > or =50 nmol/L, respectively (p <.05). PTH was significantly associated with handgrip strength only (p =.01). CONCLUSIONS: Vitamin D status was inversely associated with poor physical performance. Given the high prevalence of vitamin D deficiency in older populations, additional studies examining the association between vitamin D status and physical function are needed.