CONTEXT: Observational studies show an association between low vitamin D status assessed by circulating 25-hydroxyvitamin D and cardiovascular events and mortality. Data from randomized controlled trials are limited. OBJECTIVE: The aim of this study was to test whether daily doses of vitamin D(3) at 400 or 1000 IU/d for 1 yr affected conventional markers of cardiovascular disease (CVD) risk. DESIGN: We conducted a parallel-group, double-blind, placebo-controlled randomized controlled trial. Randomization was computer generated. Participants and study investigators were blinded to intervention groupings throughout the trial. SETTING: The study was conducted at the Clinical Research Facility, University of Aberdeen, United Kingdom. PARTICIPANTS: A total of 305 healthy postmenopausal women aged 60-70 yr were recruited for the study. INTERVENTION: Each woman received a daily capsule of 400 or 1000 IU vitamin D(3) or placebo randomly allocated. MAIN OUTCOME MEASURES: Primary outcomes were serum lipid profile [total, high-density lipoprotein, and low-density lipoprotein cholesterol; triglycerides; and apolipoproteins A-1 and B100], insulin resistance (homeostatic model assessment), inflammatory biomarkers (high-sensitivity C-reactive protein, IL-6, soluble intracellular adhesion molecule-1), and blood pressure. RESULTS: A total of 265 (87%) participants completed all study visits. Small differences between groups for serum apolipoprotein B100 change [repeated measures ANOVA, P=0.04; mean (sd), -1.0 (10.0) mg/dl (400 IU); -1.0 (10.0) mg/dl (1000 IU); and +0.02 (10.0) mg/dl (placebo)] were not considered clinically significant. Other systemic markers for CVD risk remained unchanged. There was significant seasonal variation in systolic and diastolic blood pressure independent of vitamin D dose (P<0.001, linear mixed model). Mean (sd) reduction in systolic blood pressure from winter to summer was -6.6 (10.8) mm Hg. CONCLUSIONS: Improving vitamin D status through dietary supplementation is unlikely to reduce CVD risk factors. Confounding of seasonality should be recognized and addressed in future studies of vitamin D.
CONTEXT: Observational studies show an association between low vitamin D status assessed by circulating 25-hydroxyvitamin D and cardiovascular events and mortality. Data from randomized controlled trials are limited. OBJECTIVE: The aim of this study was to test whether daily doses of vitamin D(3) at 400 or 1000 IU/d for 1 yr affected conventional markers of cardiovascular disease (CVD) risk. DESIGN: We conducted a parallel-group, double-blind, placebo-controlled randomized controlled trial. Randomization was computer generated. Participants and study investigators were blinded to intervention groupings throughout the trial. SETTING: The study was conducted at the Clinical Research Facility, University of Aberdeen, United Kingdom. PARTICIPANTS: A total of 305 healthy postmenopausal women aged 60-70 yr were recruited for the study. INTERVENTION: Each woman received a daily capsule of 400 or 1000 IU vitamin D(3) or placebo randomly allocated. MAIN OUTCOME MEASURES: Primary outcomes were serum lipid profile [total, high-density lipoprotein, and low-density lipoprotein cholesterol; triglycerides; and apolipoproteins A-1 and B100], insulin resistance (homeostatic model assessment), inflammatory biomarkers (high-sensitivity C-reactive protein, IL-6, soluble intracellular adhesion molecule-1), and blood pressure. RESULTS: A total of 265 (87%) participants completed all study visits. Small differences between groups for serum apolipoprotein B100 change [repeated measures ANOVA, P=0.04; mean (sd), -1.0 (10.0) mg/dl (400 IU); -1.0 (10.0) mg/dl (1000 IU); and +0.02 (10.0) mg/dl (placebo)] were not considered clinically significant. Other systemic markers for CVD risk remained unchanged. There was significant seasonal variation in systolic and diastolic blood pressure independent of vitamin D dose (P<0.001, linear mixed model). Mean (sd) reduction in systolic blood pressure from winter to summer was -6.6 (10.8) mm Hg. CONCLUSIONS: Improving vitamin D status through dietary supplementation is unlikely to reduce CVD risk factors. Confounding of seasonality should be recognized and addressed in future studies of vitamin D.
Authors: Jennifer C Seida; Joanna Mitri; Isabelle N Colmers; Sumit R Majumdar; Mayer B Davidson; Alun L Edwards; David A Hanley; Anastassios G Pittas; Lisa Tjosvold; Jeffrey A Johnson Journal: J Clin Endocrinol Metab Date: 2014-07-25 Impact factor: 5.958
Authors: Paulette D Chandler; Lu Wang; Xi Zhang; Howard D Sesso; Manickavasagar V Moorthy; Obiageli Obi; Joshua Lewis; Richard L Prince; Jacqueline S Danik; JoAnn E Manson; Meryl S LeBoff; Yiqing Song Journal: Nutr Rev Date: 2015-07-14 Impact factor: 7.110
Authors: S Salekzamani; H Mehralizadeh; A Ghezel; Y Salekzamani; M A Jafarabadi; A S Bavil; B P Gargari Journal: J Endocrinol Invest Date: 2016-07-11 Impact factor: 4.256
Authors: Marcella D Walker; Elaine Cong; Anna Kepley; Marco R Di Tullio; Tatjana Rundek; Shunichi Homma; James A Lee; Rui Liu; Polly Young; Chiyuan Zhang; Donald J McMahon; Shonni J Silverberg Journal: J Clin Endocrinol Metab Date: 2013-11-27 Impact factor: 5.958
Authors: John P Forman; Jamil B Scott; Kimmie Ng; Bettina F Drake; Elizabeth Gonzalez Suarez; Douglas L Hayden; Gary G Bennett; Paulette D Chandler; Bruce W Hollis; Karen M Emmons; Edward L Giovannucci; Charles S Fuchs; Andrew T Chan Journal: Hypertension Date: 2013-04 Impact factor: 10.190