Low Vitamin D levels associated with Allergic Asthma, finds Study

On comparing the number of eosinophils between asthmatic patients with vitamin D concentrations <20 ng/mL and those with VD ≥20 ng/mL, the researchers found that the former had a noticeably higher concentration of eosinophils in peripheral blood.

"These findings fully justify the analysis of the repercussions of vitamin D deficiency at the eosinophil level, i.e., eosinophil count and the functional level," the researchers suggest.

Vitamin D (VD) deficiency is the most frequent hypovitaminosis worldwide. In the adult population, the prevalence of VD deficiency (<20 ng/mL) is about 40%. Vitamin D is mostly recognized for its impact on phosphorus and calcium metabolism as well as bone metabolism; however, an increasing number of extraosseous effects are increasingly drawing attention.

Dante Daniel Hernández-Colín and colleagues from Mexico aimed to evaluate the role that serum vitamin D concentration in the number of eosinophils in peripheral blood in adults with allergic asthma.

The study included 142 patients with allergic asthma. They were categorized based on different cutoff points for eosinophils: ≥200, ≥300, ≥400, and ≥500 cells/mL. The VD concentration was stratified into <20 and ≥20 ng/mL. Multivariate analysis was used to explore the association between vitamin D (independent variable) and eosinophils (dependent variable).

The study revealed the following findings:

• The average number of eosinophils in the included patients was 418 cells/mL, and 33.8% of the included patients had vitamin D concentrations ≥20 ng/mL.
• Asthmatic patients with vitamin D< 20 ng/mL had a higher mean concentration of eosinophils than did asthmatic patients with vitamin D ≥20 ng/mL (464 ± 377.7 eosinophils/mL versus 327.8 ± 247.2 eosinophils/mL).
• Vitamin D was inversely correlated with eosinophil count (rho = 0.244).
• In the multivariate analysis, vitamin D <20 ng/mL showed a significant inverse association with each cutoff value for eosinophilia (odds ratio >1).

To sum up, Vitamin D levels < 20 ng/mL were associated with a greater number of total eosinophils in peripheral blood in adults with allergic asthma.

"Based on the study results, vitamin D deficiency in allergic asthma patients is not infrequent, as up to 70% had VD concentrations lower than 20 ng/mL," the researchers reported.

"There is a need for studies that analyzed the use of vitamin D supplements as a complementary therapy for asthma treatment," they concluded.

Reference:

Hernández-Colín DD, Bedolla-Barajas M, Morales-Romero J, Robles-Figueroa M, Bedolla-Pulido A, del Rosario Arroyo-Sánchez N. Serum vitamin D is inversely associated with blood eosinophil count among adults with allergic asthma. Thorac Res Pract. 2023;24(4):208-213.