Serum folate concentrations, asthma, atopy, and asthma control in Peruvian children

Abstract

Background The relationship between folate status and asthma-related outcomes has not been carefully examined in low- and middle-income countries where folate deficiency is common. Methods Ancillary analysis of an unmatched case-control study in which we analyzed serum folate concentrations in 412 children with asthma and 342 controls living in peri-urban communities in Lima, Peru. We examined baseline associations between folate and asthma, atopy, total serum IgE, pulmonary function, and fractional exhaled nitric oxide. We then followed children with asthma longitudinally for 6–9 months and assessed associations between folate and odds of uncontrolled asthma (defined as Asthma Control Test score ≤ 19) and of ≥1 emergency visits during follow-up. Results A 10 ng/mL decrease in serum folate was associated with 45% higher adjusted odds of asthma (OR=1.45, 95% CI 1.05–2.02). The folate-asthma relationship differed by atopic status: a 10 ng/mL decrease in serum folate was associated with a 2.4-fold higher odds of asthma among children without atopy (2.38, 1.20–4.72) and 23% higher odds of asthma in children with atopy (1.23, 0.85–1.80). Among children with asthma, a 10 ng/mL decrease in serum folate was associated with 62% higher odds of uncontrolled asthma (1.62, 1.02–2.56) and 73% higher odds of ≥1 emergency visits during follow-up (1.73, 1.05–2.85). Conclusions Serum folate concentrations were inversely associated with asthma, but this effect was stronger in children without atopy. Among children with asthma, lower serum folate concentrations were associated with higher risk of uncontrolled asthma.

Association between Serum Folic Acid Levels and Asthma in the Korean Population: A Study Based on the 2016–2018 Korea National Health and Nutrition Examination Survey

“…Our findings are consistent with those of previous studies [ 11 , 14 ], which stated that serum folate levels were inversely correlated with the odds of asthma. In Denmark, a study involving 6,784 adult participants aged 30–60 years reported that folate deficiency was significantly associated with self-reported physician-diagnosed asthma (OR, 1.37; 95% CI, 1.05–1.79) [ 11 ].…”

Association Between Serum Folate and Lung Function in People with and without Chronic Obstructive Pulmonary Disease: Results from NHANES 2007–2012.

“…It is known that folate possesses antioxidant activity, which helps to eliminate free radicals and is associated with the inhibition of oxidative stress-induced cell apoptosis 30 . This antioxidant activity may prevent lung function deterioration by reducing in ammation pathways relevant to the pathogenesis of COPD in patients 31 . The sensitivity of folate to oxidative stress may help reduce airway in ammation in COPD patients, as airway in ammation is involved in the pathogenesis of COPD 32 .…”

High serum folate level is positively associated with pulmonary function in elderly Korean men, but not in women

“…Folate is known to have antioxidant activity, removes free radicals, and is associated with oxidative stress-induced apoptosis 20 . This antioxidant activity plays a role in preventing the deterioration of pulmonary function by lowering the pathway inflammation associated with pathogenesis in COPD patients 21 . Furthermore, higher serum folate levels have been reported to play a role in lowering natural killer cell cytotoxicity, which is potentially a biological mechanism 22 .…”