Objective
To determine the effects of high-dose vitamin D on insulin sensitivity in Polycystic Ovary Syndrome (PCOS).
Design
Randomized placebo-controlled trial.
Setting
Academic medical center.
Patients
28 PCOS women.
Interventions
Vitamin D3 12,000 International Units or placebo daily for 12 weeks.
Main Outcome Measures
The primary outcome was quantitative insulin sensitivity check index (QUICKI). Secondary outcomes included glucose and insulin levels during a 75-gram oral glucose tolerance test and blood pressure.
Results
Twenty-two women completed the study. Compared to placebo, vitamin D significantly increased 25-hydroxyvitamin D (mean (95% confidence interval) in vitamin D group 20.1 (15.7 to 24.5) ng/ml at baseline and 65.7 (52.3 to 79.2) ng/ml at 12 weeks; placebo 22.5 (18.1 to 26.8) ng/ml at baseline and 23.8 (10.4 to 37.2) ng/ml at 12 weeks). There were no significant differences in QUICKI and other measures of insulin sensitivity, however we observed trends towards lower 2-hour insulin and lower 2-hour glucose. We also observed a protective effect of vitamin D on blood pressure.
Conclusions
In women with PCOS, insulin sensitivity was unchanged with high-dose vitamin D but there was a trend towards decreased 2-hour insulin and a protective effect on blood pressure.
Clinical Trial registration number
ClinicalTrials.gov Identifier: NCT00907153
Six months of heavy resistance ST may reduce resting BP in older persons. According to the latest guidelines from the Joint National Committee for the Detection, Evaluation, and Treatment of Hypertension, the changes in resting BP noted in the present study represent a shift from the high normal to the normal category.
A 6-month RT program tends to improve insulin action in insulin-resistant older adults. These results suggest that RT may be useful in ameliorating insulin resistance that often occurs with physical inactivity, obesity, and loss of muscular strength in older insulin resistant men and women.
We measured brachial and femoral artery flow velocity in eight subjects and peroneal and median muscle sympathetic nerve activity (MSNA) in five subjects during tilt testing to 40 degrees. Tilt caused similar increases in MSNA in the peroneal and median nerves. Tilt caused a fall in femoral artery flow velocity, whereas no changes in flow velocity were seen in the brachial artery. Moreover, with tilt, the increase in the vascular resistance employed (blood pressure/flow velocity) was greater and more sustained in the leg than in the arm. The ratio of the percent increase in vascular resistance in leg to arm was 2.5:1. We suggest that the greater vascular resistance effects in the leg were due to an interaction between sympathetic nerve activity and the myogenic response.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.