**9. Diabetes**

A meta‐analysis of 11 prospective studies involving 3612 cases and 55,713 non‐case partici‐ pants suggested a strong inverse association between serum 25(OH)D concentration and incidence of type 2 diabetes. Results suggested that optimal levels may reduce the risk of future diabetes by 41% [66].

Other contrasting meta‐analysis of 15 trials did not find sufficient evidence to recommend vitamin D supplementation for improving glycemia or insulin resistance in obese patients with diabetes, normal fasting glucose levels, or impaired glucose tolerance [67].
