INS and diabetes mellitus: In a study published in 2011, it was stated that low vitamin D levels increased prediabetes risk, and in healthy adolescent males, the insulin levels decreased as the vitamin D level increased.8 Pittas et al, reported that the type 2 diabetes risk was lower for those whose 25(OH)D levels were higher.9 On the other hand, in a study carried out in postmenopausal women, it has been reported that low vitamin D levels were not associated with diabetes risk.20