Kohlhoff, GeorgiaKirwan, RichardMushtaq, Sohail2024-09-302024-09-302024-09-142023-12-21Kohlhoff, G., Kirwan, R., & Mushtaq, S. (2024). The effect of vitamin D supplementation on markers of insulin resistance in women with polycystic ovarian syndrome: a systematic review. European Journal of Nutrition, 63, 2859–2869. https://doi.org/10.1007/s00394-024-03489-61436-620710.1007/s00394-024-03489-6http://hdl.handle.net/10034/629052The version of record of this article, first published in [European Journal of Nutrition], is available online at Publisher’s website: http://dx.doi.org/10.1007/s00394-024-03489-6Insulin 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. 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. A systematic search was conducted using PubMed, Medline and Web of Science databases from January 2000 up to November 2023. Randomized controlled trials that assessed the effects of vitamin D supplementation in women with PCOS, on fasting glucose, fasting insulin, glycated haemoglobin (HbA1c) or homeostatic model assessment for insulin resistance (HOMA-IR) were included. 9 studies were identified. Study populations ranged from 28 to 180 participants, with mean ages ranging from 22 to 30 years. Daily vitamin D doses ranged from 1714-12,000 IU. Of the included studies, 3 reported statistically significant reductions in fasting glucose, 2 reported reductions in fasting insulin, 2 reported reductions in HOMA-IR, none reported reductions in HbA1c and 5 reported no differences in any of the relevant outcomes. In conclusion, in RCTs of vitamin D supplementation in women with PCOS, the majority of studies do not report statistically significant improvements in fasting glucose, fasting insulin, HbA1c or HOMA-IR. However, as a minority of studies report some statistically significant results, further investigation may be warranted. PROSPERO ID: CRD42023486144. [Abstract copyright: © 2024. The Author(s).]https://creativecommons.org/licenses/by/4.0/Insulin resistanceVitamin DPolycystic ovary syndromeDiabetesGlycemic controlArticle1436-6215European Journal of Nutrition2024-09-3063