Vitamin D and Nonskeletal Complications among Egyptian Sickle Cell Disease Patients

Abstract

Lower levels of vitamin D have been documented in many patients with sickle cell disease (SCD), but data are still inconclusive regarding the association between vitamin D deficiency (VDD) and the occurrence or the severity of various SCD complications. Our study aimed to detect the prevalence of vitamin D deficiency among Egyptian patients with SCD and to associate it with the clinical course of the disease. We measured the level of 25-hydroxy vitamin D in 140 children (age from 4.3 to 15.5years), 80 patients with SCD and 60 controls using enzyme-linked immunosorbent assay. Vitamin D was deficient in 60% of SCD compared to 26.7% of controls. Severe VDD was significantly higher in SCD patients than controls. Patients were divided into 2 groups; Normal group (32 patients) and Deficient group (48 patients). There were statistically significant differences between the 2 groups regarding their age, height percentile, the presence of clinical jaundice, and osseous changes (P values 0.043, 0.024, 0.001, and 0.015, respectively). Hemoglobin and hematocrit values were significantly lower in Deficient group (P values 0.022 and 0.004, respectively) while the levels of aspartate aminotransferase, lactate dehydrogenase, and total and indirect bilirubin were significantly higher in the same group (P values 0.006, 0.001, 0.038, and 0.016, respectively). The frequency of blood transfusions, hospitalization, and vasoocclusive crisis previous year as well as the history of bone fracture and recurrent infections proved to be significantly higher in Deficient group. These findings suggest that VDD may play a role in the pathogenesis of hemolysis and other complication of SCD. Vitamin D monitoring and supplementation in patients with SCD should be implemented as a standard of care to potentially improve health outcomes in these affected patients.

A Meta-analysis on Vitamin D Deficiency in Patients with Sickle Cell Disease

“…Several peculiar characteristics of SCD could explain the high prevalence and increased risk of VDD among patients with SCD, such as: impaired absorption by the damaged intestinal mucosa as a complication of SCD; decreased level of vitamin D binding protein due to the inflammatory condition in SCD; increased physiological demands due to the fast turnover in the process of erythrocytosis in SCD; and reduced levels of nutritional status, physical activity, and exercise in patients with SCD [12,28,30,40,44,46,49].…”

“…A few of the reviewed studies assessed the correlation between vitamin D status and SCD-related health complications. Hamdy et al [49] showed a significant correlation between serum vitamin D level and the biomarkers of hemolysis (lower level of hemoglobin and a higher level of aspartate aminotransferase, lactate dehydrogenase, and bilirubin), and the clinical course and complications of SCD (frequency of blood transfusions and hospitalization, occurrence of vaso-occlusive crises, and recurrent infections). Similarly, Mandese et al [44] demonstrated the significant negative correlation between levels of vitamin D and clinical indicators of the SCD severity (hospitalization and number of days of hospital admissions).…”

“…Full texts of 40 studies were screened, and 15 studies were subsequently excluded because of insufficient data to estimate the outcomes of interest (Figure 1). A total of 25 studies published from 1993 to 2019 that met the eligibility for data were used for qualitative and quantitative syntheses: 10 studies from the Americas [12,[28][29][30][31][32][33][34][35][36]; six studies from Asia [37][38][39][40][41][42]; five studies from Europe [43][44][45][46][47]; two studies from Africa [48,49], one study that used samples from both Jamaica and West Africa [50], and one study that used samples from both Brazil and Nigeria [51].…”

Comparison of two vitamin D supplementation strategies in children with sickle cell disease: a randomized controlled trial

“…1 Compared with healthy ethnicity-matched children, children with SCD have more profound vitamin D depletion. [2][3][4][5][6][7] The exact reason for this observation is unknown, but impaired vitamin D metabolism due to sickle cell nephropathy is among the proposed aetiologies. 8 Children with SCD suffer from multiple complications, including vaso-occlusive events, which result in frequent emergency department (ED) visits and hospitalizations.…”

“…Prevalence of vitamin D deficiency is high in children with sickle cell disease (SCD) with rates ranging from 56% to 96% 1 . Compared with healthy ethnicity‐matched children, children with SCD have more profound vitamin D depletion 2‐7 . The exact reason for this observation is unknown, but impaired vitamin D metabolism due to sickle cell nephropathy is among the proposed aetiologies 8 …”