Endocrine Abstracts

Introduction: Vitamin D deficiency is associated with higher risk of severe COVID-19, and type 2 diabetic patients are a vulnerable group. We described an alarming rate of vitamin D deficiency (around 80.0% with plasma calcifediol <30 ng/ml) in unsupplemented type 2 diabetes patients during the 2020 spring lockdown and the following winter in Northern Gran Canaria. There is an increasing awareness of this problem, both in family physicians and the general population, and the use of vitamin D supplements is rising.

Objectives: To assess the prevalence of vitamin D deficiency in type 2 diabetic patients from Northern Gran Canaria during the late autumn-early winter period (November 2021 to January 2022), and its relationship with vitamin D supplementation.

Methods: Plasma calcifediol levels were sampled in an unselected type 2 diabetic population, and recorded anonymously along with age, gender and vitamin D supplementation status. All included patients gave their informed consent.

Results: Data were obtained from 217 consecutive patients; only 2 (<1%) were excluded due to lack of consent.129 were female (59.4%), mean age was 58.6±13.9 years. 138 (60.8%) were taking vitamin D supplements. Mean plasma calcifediol was 35.7±14.9 ng/ml; but it was lower than recommended (< 30 ng/ml) in 85 (39.2%) of the patients, deficient (< 20 ng/ml) in 35 (16.1%) and severely deficient (<12 ng/ml) in 8 (3.7%). In vitamin D supplemented patients, mean calcifediol was 43.2±11.6 ng/ml, with 20 patients (14.5%) <30 ng/ml, 6 (4.3%) <20 ng/ml, none < 12 ng/ml and 1 (0.7%) > 80 ng/ml. In unsupplemented patients, mean calcifediol was 22.7±9.3 ng/ml, with 65 (82.2%) < 30 ng/ml, 29 (36.7%) < 20 ng/ml and 8 (10.1%) <12 ng/ml). Plasma calcifediol was significantly higher in supplemented patients (mean difference 20.5±5.9 ng/ml, unpaired t-test, P < 0.0001) and the proportions of low, deficient and severely deficient patients were significantly lower (Fisher’s exact test, P < 0.0001, P < 0.0001 and P=0.0002, respectively).

Conclusions: The prevalence of vitamin D deficiency during the late autumn-early winter months in our unsupplemented type 2 diabetic population remains extremely high. However, the use of supplements is increasing, about 60% of our patients at present (45% in our previous survey 1 year ago). In supplemented patients vitamin D status is satisfactory with 4% deficient, none severely deficient and < 1% above the recommended level.