Relationship of vitamin D deficiency to cardiovascular disease and glycemic control in patients with type 2 diabetes mellitus: The Silesia Diabetes-Heart Project

Abstract

Introduction: Vitamin D (VD) has a pleiotropic effect on many health aspects yet the results of studies regarding vitamin D deficiency (VDD) and both glycemic control and cardiovascular disease (CVD) are conflicting.

Objective: To determine the prevalence of VDD and its associations with CVD and glycemic control among patients with type 2 diabetes (T2DM).

Patients and methods: This was an observational study in T2DM patients recruited in the Diabetology Clinic in Zabrze, Poland (April-September 2019, April-September 2020). The presence of CVD was determined based on medical records. Blood biochemical parameters, densitometry and carotid artery ultrasound examination were performed. Control of diabetes was assessed based on HbA1c. A serum VD level <20 ng/ml was considered as VDD.

Results: The prevalence of VDD in 197 patients was 36%. CVD was evident in 27% patients with VDD and in 33% patients with VD within the normal range (VDS) (P = 0.34). The difference between groups regarding diabetes control was insignificant (P = 0.05) as VDD patients had the median value (first quartile Q1; third quartile Q3) of HbA1c: 7.50% (Q1: 6.93%; Q3: 7.90%); for VDS it was: 7.50% (Q1: 6.56%; Q3: 7.50%). VDD patients were more often treated with sodium-glucose cotransporter-2 inhibitors (SGLT-2i) (44% vs 25%, P = 0.01).

Conclusions: About one-third of subjects were VDD. The groups did not differ in terms of CVD occurrence and the difference in glycemic control was insignificant. Patients with VDD were more often treated with SGLT-2i what needs further investigation.