Vitamin D Replacement Effect on Platelet Counts.

Objective: To determine the effect of vitamin D treatment on platelet counts according to age groups in patients with vitamin D deficiency.

Study Design: An observational study.

Place And Duration Of Study: Outpatient Clinics, Department of Internal Medicine, Faculty of Medicine, Lokman Hekim University Hospital, Ankara, Turkey from January 1st to December 31st, 2020.

Methodology: A total of 1,230 participants, who were treated for vitamin D deficiency after admission to hospital for various reasons, were enrolled. Patients under 18 years of age, having chronic diseases, using medicines affecting platelets and who had 25-hydroxyvitamin D levels above 74.88 nmol/L were excluded from study. Participants were divided into three groups according to ages: 18 to 30 (Group 1), 30 to 50 (Group 2), and greater than 50 years (Group 3). Complete blood count parameters and vitamin D level data before and after vitamin D replacement treatment were compared.

Results: Platelet counts and mean platelet volume levels were found to be significantly lower in participants after vitamin D treatment. Changes in hemoglobin and neutrophil counts were insignificant. Although there was no difference between mean platelet counts and age groups before treatment, significant differences were noted after vitamin D treatment (p=0.004). Correlation between vitamin D levels and changes in platelet levels compared to treatment beginning was found to be significant (r=-0.159, p<0.001).

Conclusion: Vitamin D treatment lowered platelet counts. This may be beneficial in medical conditions such as essential thrombocythemia in which platelet counts are higher than normal, and may help decrease platelet counts. Key Words: Complete blood count, Blood platelet count, Vitamin D.