Vitamin D Status Modifies the Response to Indoor Particulate Matter in Obese Urban Children with Asthma

Abstract

Background: Indoor fine particulate air pollution (PM2.5) is linked to asthma morbidity; however, whether vitamin D status influences individual susceptibility to airborne exposures is unclear. Objective: We aimed to determine if vitamin D modifies effects of indoor PM2.5 upon asthma symptoms in urban children. Methods: 120 children aged 5–12 years with physician-diagnosed asthma were evaluated at baseline and every 3 months for 9 months. Indoor PM2.5, serum 25-hydroxy vitamin D (25-OH D) levels and asthma symptoms were simultaneously assessed at each time point. Adjusting for confounders, generalized estimating equations assessed 3-way interaction effects of 25-OH D, obesity and PM upon asthma symptoms. Results: Children were of mean (SD) age 9.7 (2.2) years, 36% were obese, and 95% self-reported black race. Mean (SD) PM2.5 indoor exposure was 38.2 (42.9) μg/m3 and 25-OH D was 19.1 (7.5) ng/ml. Three-way interaction models demonstrated significantly greater PM2.5-associated effects on daytime asthma symptoms only among obese children with low 25-OH D levels (ORPM2.5=1.26,p =0.049 at vitamin D=15.5 ng/ml, increasingly stronger PM effects at levels<15.5 ng/ml). In homes with increased PM2.5, higher 25-OH D was associated with decreased symptom odds (e.g., ORVitamin D = 0.87; p=0.049 at PM2.5 = 52.5 μg/m3, increasingly protective effects >52.5 μg/m3) among obese children. Conclusion: Among obese urban children with asthma, low individual 25-OH vitamin D enhanced adverse respiratory effects associated with indoor PM2.5. In high PM2.5 environments, 25-OH D was protective against asthma symptoms. Optimizing vitamin D status in children may help reduce asthma morbidity driven by indoor air pollution.

Structural and Social Determinants of Health in Asthma in Developed Economies: a Scoping Review of Literature Published Between 2014 and 2019

“…Special Considerations: Vitamin D Vitamin D insufficiency, higher in black populations [111], has been associated with asthma prevalence and morbidity; however, a causal mechanism remains controversial. Multiple studies support a role for vitamin D via its anti-oxidant and immunomodulatory effects [112][113][114][115][116]. Two meta-analyses of randomized clinical trials demonstrate that vitamin D supplementation reduced the rate of asthma exacerbations requiring systemic corticosteroids in both children and adults in ethnically diverse populations [117•], [118].…”

The Role and Potential Pathogenic Mechanism of Particulate Matter in Childhood Asthma: A Review and Perspective

“…As numerous studies have focused on the mechanism by which PM promotes the incidence of asthma, authors recently have demonstrated some strategies to improve the impact of PM on asthma. For instance, Bose et al have found that higher serum 25-hydroxy (25-OH) vitamin D levels could reduce the adverse respiratory response associated with indoor PM 2.5 exposures among obese urban children with asthma [82]. Moreover, fatty acid intake, specifically Omega-3 and Omega-6, can modify asthma severity and response to indoor air pollution in children [83].…”

The effect of particulate matter reduction by indoor air filter use on respiratory symptoms and lung function: A systemic review and meta-analysis

“…Vitamin D is also reported to help control asthma. (39) Bose et al demonstrated that a decreased level of vitamin D in obese children with asthma is associated with a higher level of symptoms following a 10 unit increase in PM 2.5 (41).…”