Effect of daily 2000 IU versus 800 IU vitamin D on blood pressure among adults age 60 years and older: a randomized clinical trial.

BACKGROUND: Observational studies report higher blood pressure (BP) among individuals with lower 25-hydroxyvitamin D concentration. Whether dosage of vitamin D supplementation has a differential effect on BP control remains unclear. OBJECTIVE: The study aimed to determine if daily vitamin D supplementation with 2000 IU is more effective than 800 IU for BP control among older adults. METHODS: This randomized, double-blind, ancillary trial of the Zurich Multiple Endpoint Vitamin D Trial in Knee Osteoarthritis enrolled adults aged ≥60 y who underwent elective surgery due to severe knee osteoarthritis. Participants were randomly assigned to receive high dose (2000 IU) or standard dose (800 IU) daily vitamin D3 for 24 mo. Outcomes included daytime and 24-h mean systolic BP. BP variability and serum 25-hydroxyvitamin D concentration were examined in a post hoc and observational analysis. RESULTS: Of the 273 participants randomly assigned, 250 participants completed a follow-up 24-h ambulatory BP monitoring (mean age: 70.4 ± 6.4 y; 47.2% men). The difference in daytime mean systolic BP reduction between the 2000 IU (n = 123) and 800 IU (n = 127) groups was not statistically significant (-2.75 mm Hg vs. -3.94 mm Hg; difference: 1.18 mm Hg; 95% CI: -0.68, 3.05; P = 0.21), consistent with 24-h mean systolic BP. However, systolic BP variability was significantly reduced with 2000 IU (average real variability: -0.37 mm Hg) compared to 800 IU vitamin D3 (0.11 mm Hg; difference: -0.48 mm Hg; 95% CI: -0.94, -0.01; P = 0.045). Independent of group allocation, maximal reductions in mean BP were observed at 28.7 ng/mL of achieved serum 25-hydroxyvitamin D concentrations. CONCLUSIONS: While daily 2000 IU and 800 IU vitamin D3 reduced mean systolic BP over 2 y to a small and similar extent, 2000 IU reduced mean systolic BP variability significantly more compared with 800 IU. However, without a placebo control group we cannot ascertain whether vitamin D supplementation effectively reduces BP.This trial was registered at www.clinicaltrials.gov as NCT00599807.

A pooled analysis of vitamin D dose requirements for fracture prevention.

BACKGROUND: The results of meta-analyses examining the relationship between vitamin D supplementation and fracture reduction have been inconsistent. METHODS: We pooled participant-level data from 11 double-blind, randomized, controlled trials of oral vitamin D supplementation (daily, weekly, or every 4 months), with or without calcium, as compared with placebo or calcium alone in persons 65 years of age or older. Primary end points were the incidence of hip and any nonvertebral fractures according to Cox regression analyses, with adjustment for age group, sex, type of dwelling, and study. Our primary aim was to compare data from quartiles of actual intake of vitamin D (including each individual participant's adherence to the treatment and supplement use outside the study protocol) in the treatment groups of all trials with data from the control groups. RESULTS: We included 31,022 persons (mean age, 76 years; 91% women) with 1111 incident hip fractures and 3770 nonvertebral fractures. Participants who were randomly assigned to receive vitamin D, as compared with those assigned to control groups, had a nonsignificant 10% reduction in the risk of hip fracture (hazard ratio, 0.90; 95% confidence interval [CI], 0.80 to 1.01) and a 7% reduction in the risk of nonvertebral fracture (hazard ratio, 0.93; 95% CI, 0.87 to 0.99). By quartiles of actual intake, reduction in the risk of fracture was shown only at the highest intake level (median, 800 IU daily; range, 792 to 2000), with a 30% reduction in the risk of hip fracture (hazard ratio, 0.70; 95% CI, 0.58 to 0.86) and a 14% reduction in the risk of any nonvertebral fracture (hazard ratio, 0.86; 95% CI, 0.76 to 0.96). Benefits at the highest level of vitamin D intake were fairly consistent across subgroups defined by age group, type of dwelling, baseline 25-hydroxyvitamin D level, and additional calcium intake. CONCLUSIONS: High-dose vitamin D supplementation (≥800 IU daily) was somewhat favorable in the prevention of hip fracture and any nonvertebral fracture in persons 65 years of age or older. (Funded by the Swiss National Foundations and others.).

Vitamin D effects on bone and muscle.

Increasing data suggest that higher 25-hydroxyvitamin D [25(OH)D] serum concentrations are advantageous for health. At present, strong evidence for causality is available for fracture and fall prevention, while promising epidemiologic and mechanistic studies suggest a key role of vitamin D in the preservation of cardiovascular health, and the prevention of cancer and other common chronic disease. For lower extremity function, fall prevention, hip bone density, and for fracture prevention optimal benefits are observed with 25(OH)D levels of at least 75 nmol/L to 100 nmol/L [1]. This threshold may be reached in 50 % of adults with 800 to 1000 IU vitamin D per day. This manuscript will discuss the evidence of vitamin D in fall and fracture prevention and how these data transfer to the most recent recommendations by the IOF (International Osteoporosis Foundation) and the IOM (Institute of Medicine).

Effect of high-dosage cholecalciferol and extended physiotherapy on complications after hip fracture: a randomized controlled trial.

BACKGROUND: Care of elderly patients after hip fracture is not well established. METHODS: We enrolled 173 patients with acute hip fracture who were 65 years or older (79.2% women; mean age, 84 years; 77.4% living at home). Using a factorial design, we randomly allocated patients to extended physiotherapy (PT) (supervised 60 min/d during acute care plus an unsupervised home program) vs standard PT (supervised 30 min/d during acute care plus no home program; single-blinded), and to cholecalciferol therapy, 2000 vs 800 IU/d (double-blinded). Primary outcome was rate of falls; secondary outcome was rate of hospital readmissions during the 12-month follow-up. All analyses included 173 individuals and used multivariate Poisson regression analyses. RESULTS: At baseline, 50.9% of participants had 25-hydroxyvitamin D levels of less than 12 ng/mL and 97.7% of less than 30 ng/mL. We documented 212 falls and 74 hospital readmissions. Because this was a factorial design trial, all analyses tested the main effect of each treatment while controlling for the other in 173 participants. Extended vs standard PT reduced the rate of falls by 25% (95% confidence interval [CI], -44% to -1%). Cholecalciferol treatment, 2000 vs 800 IU/d, did not reduce falls (28%; 95% CI, -4% to 68%), but reduced the rate of hospital readmissions by 39% (95% CI, -62% to -1%). CONCLUSIONS: Extended PT was successful in reducing falls but not hospital readmissions, whereas cholecalciferol treatment, 2000 IU/d, was successful in reducing hospital readmission but not falls. Thus, the 2 strategies may be useful together because they address 2 different and important complications after hip fracture.

Alfacalcidol reduces the number of fallers in a community-dwelling elderly population with a minimum calcium intake of more than 500 mg daily.

OBJECTIVES: To study the effect of alfacalcidol (1alpha(OH)D3) on fall risk in community-dwelling elderly men and women. DESIGN: Randomized, double-blind, placebo-controlled intervention trial. SETTING: Basel, Switzerland. PARTICIPANTS: Three hundred seventy-eight community-dwelling elderly (191 women/187 men). INTERVENTION: Participants were randomly assigned to receive 1 microg of alfacalcidol or matched placebo daily for 36 weeks. MEASUREMENTS: Serum 25-hydoxyvitamin D3 (25(OH) D,1,25-dihydroxyvitamin D3 (D-hormone), and intact parathormone (iPTH) levels were measured using radioimmunoassay at baseline and every 12 weeks. Numbers of fallers and falls were assessed using a questionnaire during each study site visit. Dietary calcium intake was assessed at baseline using a food frequency questionnaire. RESULTS: At baseline, participants had, on average, normal vitamin D and D-hormone serum levels. Over 36 weeks, alfacalcidol treatment was associated with fewer fallers (odds ratio (OR)=0.69, 95% confidence interval (CI)=0.41-1.16) than placebo. In a post hoc subgroups analysis by medians of total calcium intake, this reduction reached significance in alfacalcidol-treated subjects with a total calcium intake of more than 512 mg/d (OR=0.45, 95% CI=0.21-0.97, P=.042) but not in those who consumed less than 512 mg/d (OR=1.00, 95% CI= 0.47-2.11, P=.998). Alfacalcidol treatment was also, independent of total calcium intake, associated with a significant 37.9% reduction in iPTH serum levels (P<.0001). No cases of clinically relevant hypercalcemia were observed. CONCLUSION: Provided a minimal calcium intake of more than 512 mg/d, alfacalcidol treatment significantly and safely reduces number of fallers in an elderly community dwelling population.

Effects of vitamin D and calcium supplementation on falls: a randomized controlled trial.

Specific receptors for vitamin D have been identified in human muscle tissue. Cross-sectional studies show that elderly persons with higher vitamin D serum levels have increased muscle strength and a lower number of falls. We hypothesized that vitamin D and calcium supplementation would improve musculoskeletal function and decrease falls. In a double-blind randomized controlled trial, we studied 122 elderly women (mean age, 85.3 years; range, 63-99 years) in long-stay geriatric care. Participants received 1200 mg calcium plus 800 IU cholecalciferol (Cal+D-group; n = 62) or 1200 mg calcium (Cal-group; n = 60) per day over a 12-week treatment period. The number of falls per person (0, 1, 2-5, 6-7, >7 falls) was compared between the treatment groups. In an intention to treat analysis, a Poisson regression model was used to compare falls after controlling for age, number of falls in a 6-week pretreatment period, and baseline 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D serum concentrations. Among fallers in the treatment period, crude excessive fall rate (treatment - pretreatment falls) was compared between treatment groups. Change in musculoskeletal function (summed score of knee flexor and extensor strength, grip strength, and the timed up&go test) was measured as a secondary outcome. Among subjects in the Cal+D-group, there were significant increases in median serum 25-hydroxyvitamin D (+71%) and 1,25-dihydroxyvitamin D (+8%). Before treatment, mean observed number of falls per person per week was 0.059 in the Cal+D-group and 0.056 in the Cal-group. In the 12-week treatment period, mean number of falls per person per week was 0.034 in the Cal+D-group and 0.076 in the Cal-group. After adjustment, Cal+D-treatment accounted for a 49% reduction of falls (95% CI, 14-71%; p < 0.01) based on the fall categories stated above. Among fallers of the treatment period, the crude average number of excessive falls was significantly higher in the Cal-group (p = 0.045). Musculoskeletal function improved significantly in the Cal+D-group (p = 0.0094). A single intervention with vitamin D plus calcium over a 3-month period reduced the risk of falling by 49% compared with calcium alone. Over this short-term intervention, recurrent fallers seem to benefit most by the treatment. The impact of vitamin D on falls might be explained by the observed improvement in musculoskeletal function.