Serum Folate in Asthma: Does it Correlate to Severity? A Single Center Experience

Abstract

Background: Bronchial asthma is the most common chronic childhood illness. It is characterized by airway inflammation and episodic airflow obstruction. Low serum folate has been inconsistently reported as a risk factor for bronchial asthma severity. Other studies reported an increased risk of asthma in children whose mothers received prenatal folic acid supplementation. Aim of the work: To compare serum folate level in asthmatic patients to non-asthmatic healthy controls, and to demonstrate whether folate level correlates to severity &/or frequency of asthma exacerbations and pulmonary function parameters. Methods: Forty-five asthmatic Egyptian children and an equal number of healthy controls were included. Serum folate level was measured in both groups and spirometry was performed for the asthmatic children. Results: Serum folate levels were significantly lower among patients (7.83ng/ml ± 2.47) versus controls (9.84ng/ml ± 3.47), (p value 0.002). Serum folate levels also had an inverse correlation with severity of asthma exacerbations (r = – 0.482), (p = 0.001) and their frequency (r = – 0.418), (p= 0.004). Serum folate levels inversely correlated as well with severity of asthma as a chronic illness (r = – 0.315), (p = 0.035). The cutoff point of serum folate level that was found to increase the severity of asthma exacerbations was calculated at ≤ 8.84ng/ml. Only 7 patients fell below the current normal reference range for serum folate. On the other hand, serum folate level did not significantly correlate with any of the pulmonary function test variables measured. Conclusions: Serum folate levels were lower in asthmatic children when compared to healthy controls, and it negatively correlated with asthma severity and exacerbations, but not to pulmonary function parameters. The cutoff serum folate level for increased severity of asthma exacerbations fell within the normal folate range for children. Further research is recommended to assess any possible beneficial effects for folate supplementation in asthma.