ABSTRACT
IMPORTANCE: Experts debate optimal 25-hydroxyvitamin D (25[OH]D) levels for musculoskeletal health. OBJECTIVE: To compare the effects of placebo, low-dose cholecalciferol, and high-dose cholecalciferol on 1-year changes in total fractional calcium absorption, bone mineral density, Timed Up and Go and five sit-to-stand tests, and muscle mass in postmenopausal women with vitamin D insufficiency. DESIGN, SETTING, AND PARTICIPANTS: This randomized, double-blind, placebo-controlled clinical trial was conducted at a single center in Madison, Wisconsin, from May 1, 2010, through July 31, 2013, and the final visit was completed on August 8, 2014. A total of 230 postmenopausal women 75 years or younger with baseline 25(OH)D levels of 14 through 27 ng/mL and no osteoporosis were studied. INTERVENTIONS: Three arms included daily white and twice monthly yellow placebo (n=76), daily 800 IU vitamin D3 and twice monthly yellow placebo (n=75), and daily white placebo and twice monthly 50,000 IU vitamin D3 (n=79). The high-dose vitamin D regimen achieved and maintained 25(OH)D levels≥30 ng/mL. MAIN OUTCOMES AND MEASURES: Outcome measures were 1-year change in total fractional calcium absorption using 2 stable isotopes, bone mineral density and muscle mass using dual energy x-ray absorptiometry, Timed Up and Go and five sit-to-stand tests, functional status (Health Assessment Questionnaire), and physical activity (Physical Activity Scale for the Elderly), with Benjamini-Hochberg correction of P values to control for the false discovery rate. RESULTS: After baseline absorption was controlled for, calcium absorption increased 1% (10 mg/d) in the high-dose arm but decreased 2% in the low-dose arm (P = .005 vs high-dose arm) and 1.3% in the placebo arm (P = .03 vs high-dose arm). We found no between-arm changes in spine, mean total-hip, mean femoral neck, or total-body bone mineral density, trabecular bone score, muscle mass, and Timed Up and Go or five sit-to-stand test scores. Likewise, we found no between-arm differences for numbers of falls, number of fallers, physical activity, or functional status. CONCLUSIONS AND RELEVANCE: High-dose cholecalciferol therapy increased calcium absorption, but the effect was small and did not translate into beneficial effects on bone mineral density, muscle function, muscle mass, or falls. We found no data to support experts' recommendations to maintain serum 25(OH)D levels of 30 ng/mL or higher in postmenopausal women. Instead, we found that low- and high-dose cholecalciferol were equivalent to placebo in their effects on bone and muscle outcomes in this cohort of postmenopausal women with 25(OH)D levels less than 30 ng/mL. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00933244.
Subject(s)
Cholecalciferol/administration & dosage , Postmenopause/physiology , Vitamin D Deficiency , Absorptiometry, Photon/methods , Aged , Bone Density/drug effects , Bone Density Conservation Agents/administration & dosage , Calcium Radioisotopes/pharmacology , Dose-Response Relationship, Drug , Double-Blind Method , Drug Monitoring , Female , Humans , Middle Aged , Motor Activity/drug effects , Physical Endurance/drug effects , Radiopharmaceuticals/pharmacology , Treatment Outcome , Vitamin D/analogs & derivatives , Vitamin D/blood , Vitamin D Deficiency/blood , Vitamin D Deficiency/diagnosis , Vitamin D Deficiency/drug therapyABSTRACT
OBJECTIVES: To examine changes in health and lifestyle indicators over 6 months in persons with type 2 diabetes mellitus receiving nutrition counseling from a registered dietitian, and to promote dietetics professionals' participation in outcomes monitoring and research. DESIGN: Prospective, noncontrolled descriptive study. SUBJECTS: Two hundred forty-four physician-referred adults with type 2 diabetes mellitus from 31 sites who received usual and customary nutrition counseling, and 83 registered dietitians. MAIN OUTCOME MEASURES: Glycemic control, coronary heart disease risk, self-management behaviors, and quality of life were measured at baseline, 3 months, and 6 months. Dietitians' perceptions of the study were also measured. STATISTICAL ANALYSIS: Repeated-measures analysis of variance, paired t test, Wilcoxon signed rank test, sign test, Spearman correlation, and chi 2 analysis were conducted. RESULTS: Weight and glycemic control, coronary heart disease risk, and self-management behaviors improved significantly between baseline and 3 months and baseline and 6 months. Weight, body mass index, and glycosylated hemoglobin value also improved significantly between 3 months and 6 months. Increased time and/or number of sessions with the registered dietitian were associated with weight loss and reduced glycosylated hemoglobin, fasting plasma glucose, total cholesterol, and triglyceride levels. Self-perceived health status and missed workdays were significantly improved at 6 months. Difficulty obtaining current laboratory values, lack of time, and inability to reach subjects for follow-up presented the greatest obstacles for the dietitians. CONCLUSIONS: Positive outcomes were observed in adults receiving nutrition intervention for type 2 diabetes. Clinical improvements were greatest between baseline and 3 months, with stabilization between 3 months and 6 months, suggesting ongoing intervention is needed to support continued clinical progress. Dietitians found participation in this state affiliate-coordinated research project rewarding.
