Background: Insulin resistance (IR) is a common pathology in women with polycystic ovarian syndrome (PCOS) involved in increased rates of cardiometabolic disease such as diabetes and cardiovascular disease. Low serum vitamin D is often associated with insulin resistance but there is no consensus on whether vitamin D supplementation can ameliorate markers of IR in PCOS.
Objectives: We assessed evidence on the effects of vitamin D supplementation (≥ 1000 IU/day), without the use of additional supplements or other pharmacological treatments known to affect IR, on markers of IR and glycemic control in women with PCOS.