The protocol has been modified by adding the following specific aim: To compare vascular function in healthy age and BMI similar matched women to PCOS women pre-treatment. Our hypothesis is that PCOS women will have greater attenuations in retinal vascular reactivity compared to healthy control women, demonstrating poorer endothelial function. We are currently recruiting healthy women who are age and BMI similar to the PCOS women and measure their retinal vascular reactivity for comparisons to the PCOS women's pre-treatment vascular reactivity. These healthy women will only have a baseline visit in which retinal vascular reactivity will be measured. They will not be enrolled in the placebo or Vitamin D randomization process as described above.