Decreased Levels of Zinc Associated With Worse SCD Severity in Children, Adolescents

Monitoring levels of zinc in patients with sickle cell disease (SCD) may aid in reducing morbidity of the disease, as well as the prevalence of infections, suggest learnings from a new review. The review of 41 articles also indicated that leveraging zinc supplementation in these patients is a safe and potentially effective approach for these patients.

When at sufficient levels in the body, zinc is able to reduce the risk of vaso-occlusive crisis (VOC) in sickle cell anemia due to its antioxidant effects. As a result, when levels decrease, patients may experience complications, such as growth retardation, delayed wound healing, and increased VOC.

“Decreased blood levels of antioxidant trace elements, such as zinc, may contribute to the pathophysiology of SCD. The most recent studies have shown that only children are evaluated and followed up regarding zinc concentrations in SCD,” wrote the researchers, urging for future research to be carried out in adult populations. “We found in children and adolescents a direct association between zinc insufficiencies/deficiencies with increased disease severity in SCD. Unfortunately, adults do not have the same follow-up, and there is only little/nonsatisfying data available in the literature as far as we can see.”

Across the available studies on zinc levels in young patients with SCD, the researchers found lower levels of zinc in patients compared with controls. For instance, one Iraqi study, serum zinc levels were a mean of 67.2 μg/dl, which was lower than the control group.

The studies should a zinc deficiency can cause increased white blood cell counts and cytokine production, as well as negatively impact weight, height, and body mass index.

Findings from studies suggested that zinc supplementation has positive implications for growth and body composition in children with the disease. Supplementation has also been shown to be effective in reducing VOC and hospitalizations in patients. In one study, researchers showed that prolonged (2 to 3 years) supplementation with zinc acetate (50-75 mg) led to decreased infections, hospitalizations, and VOC. Other studies supported the findings that zinc supplementation decreased the risk of infectioun.

Notably, the researchers found one study that showed oxidative stress may be higher in patients with the HbSS than in patients with the HbSC genotype. Using atomic absorption spectrometry, the study showed levels of 85.0 μg/dl among patients with HbSC compared with levels of 66.5 μg/dl in patients with HbSS. Some research included in the analysis also suggested that zinc levels are reduced in patients with the HbSS genotype, particularly those with VOC.

The authors suggested further research in adults since studies show only children with SCD are evaulated and followed up regarding zinc concentrations. However, the research shows the asociation between zinc decifiencies and increased SCD severity occurs in both children and adults.

"New research must be carried out, especially for adults, to ensure more remarkable survival for this population," the authors concluded. "Thus, monitoring zinc status in SCD children, adolescents, and adults appears essential for reducing disease-associated morbidity and infections. Zinc supplementation is a safe therapeutic modality for treating SCD patients."

Reference

Miranda C, Vermeulen-Serpa K, Pedro A, Brandão-Neto J, Vale S, Figueiredo M. Zinc in sickle cell disease: A narrative review. J Trace Elem Med Biol. Published online April 4, 2022. doi:10.1016/j.jtemb.2022.126980