PCOS: oral vitamin D can reduce the risk of diabetes

Insulin sensitivity is improved in terms of decreasing fasting glucose concentration and Insulin Resistance Index by Homeostatic Model Assessment (HOMA-IR) value. Additionally, HOMA-IR value also decreased with daily dose and low doses (<4000 IU, daily) of vitamin D alone, but not with weekly dose.

Karolina Łagowska, Institute of Human Nutrition and Dietetics, Poznań University of Life Sciences, Poland, and colleagues conducted systematic review and meta-analysis of data available in randomized controlled trials to assess the effect of vitamin D supplementation (alone or in co-supplementation) on insulin resistance in women with PCOS.

• There was no significant overall effect of vitamin D supplementation on fasting glucose concentrations (SMD: 1.54, 95% CI: -5.17, 0.85, P= .16) or when different doses of vitamin D or when supplementation manner was considered.


• There was significant decrease in fasting glucose concentration with type of supplementation (vitamin D alone: SMD: 2.18; 95% CI: −5.70, 0.28; P =.51; co-supplement: SMD: 1.54; 95% CI:−6.77, −0.74; P = .0146).


• There was a significant decline in HOMA-IR value when vitamin D was supplemented with a dose <4000 IU/day compared with high dose (high dose, SMD, 0.18; P=.9914, vs low dose, SMD,−0.31; P=.0016; overall effects, Z=1.1770; P=.2392).