This meta- analysis concludes that hypovitaminosis D is associated with increased risk of hyperglycemia both in diabetic and non-diabetic subjects .
There is evidence that vitamin D status is associated with type 2 diabetes .
Many observational studies have been performed investigating the relationship of vitamin D status and circulating biomarkers of glycemic regulation .
To find out whether this association holds , we conducted a systematic review and meta- analysis of cross sectional and longitudinal studies .
25-Hydroxyvitamin D [25(OH)D] levels and diabetic foot ulcer: is there any relationship?
AIMS In recent years , there has been an effort to underst and possible roles of 25(OH)D , including its role in the immune system particularly on T cell medicated immunity , pancreatic insulin secretion and insulin action . 25(OH)D stimulates the cell differentiation and reduces cell proliferation , which is essential for cell growth and wound healing . However , data on the association between low level of plasma 25(OH)D and diabetic foot syndrome are scarce . MATERIAL S AND METHODS  Circulating plasma levels of 25(OH)D were  measured in diabetic patients with ulcer ( n=162 ) and without ulcer ( n=162 ) in a prospect i ve cohort hospital based study . RESULTS Of these patients , 85.1 % had type 2 diabetes . Subjects with diabetic foot ulcer showed lower median plasma level of 25(OH)D [ 6.3(4.2 - 11.1 ) vs 28.0(21.4 - 37.0 ) ] ng/ml after adjusting the age and BMI . Regardless of the low levels of 25(OH)D in cases and controls , it was associated with neuropathy , sex ( female ) , duration of ulcer healing , and smoking status and independent of confounding factors , including BMI ( kg/m² ) , A1c ( % ) , hypertension , nephropathy , foot ulcer , retinopathy , CAD , PAD , HDL-C ( mg/dl ) and LDL-C ( mg/dl ) . The factors which predict the risk of developing ulcer independent of 25(OH)D status were A1c ( > 6.9 % ) [ OR 4.37 ; RR 1.77 ] , HDL-C ( < 40mg/dl ) [ OR 1.16 ; RR 1.07 ] , LDL-C ( > 100mg/dl ) [ OR 1.07 ; RR 1.03 ] , triglycerides ( > 200mg/dl ) [ OR 1.40 ; RR 1.19 ] , neuropathy [ OR 6.88 ; RR 3.12 ] , retinopathy [ OR 3.34 ; RR 1.91 ] , hypertension [ OR 1.64 ; RR 1.28 ] , nephropathy [ OR 3.12 ; RR 1.87 ] and smoking [ OR 4.53 ; RR 2.99 ] using odds and risk ratios . CONCLUSION It is not clear whether the suppression of delayed wound healing seen during 25(OH)D deficiency is due to the secondary effect or is a direct action of vitamin D on certain components of the immune system . Long-term r and omized trials are needed to see the impact of vitamin D supplementation on the outcome of diabetic foot patients
This meta- analysis concludes that hypovitaminosis D is associated with increased risk of hyperglycemia both in diabetic and non-diabetic subjects .
There is evidence that vitamin D status is associated with type 2 diabetes .
Many observational studies have been performed investigating the relationship of vitamin D status and circulating biomarkers of glycemic regulation .
To find out whether this association holds , we conducted a systematic review and meta- analysis of cross sectional and longitudinal studies .