Exposure amount and timing of solar irradiation during pregnancy and the risk of sensitization in children

Early exposure to sunlight and allergic morbidity: The PARIS birth cohort

The relationship between sunlight and allergies in children has received limited attention from researchers. We sought to explore how early exposure to solar radiation is associated with allergic morbidity within the PARIS birth cohort study. Our research dealt with children who attended at least one of two health checkups: at 18 months (n = 2012) and at 8-9 years (n = 1080). Early exposure to solar radiation was assessed using meteorological data (e.g., solar radiation, temperature, and relative humidity). Children with similar meteorological exposure trajectories were grouped by a longitudinal and multidimensional cluster analysis. The association between solar radiation exposure and allergic morbidity (i.e., allergic sensitization at 18 months and 8-9 years; current asthma, rhinitis, and eczema at 8-9 years) was quantified by multivariable logistic regression models adjusted for potential confounders. The effect modification of maternal vitamin D supplementation during pregnancy was tested. Four meteorological exposure trajectories were found. The trajectory with the highest exposure to early solar radiation had a reduced risk of sensitization at 8-9 years compared to the trajectory with the lowest exposure (p = 0.06). The association was statistically significant in the vitamin D supplementation group. Solar radiation during prenatal and postnatal periods was significantly associated with a lower risk of sensitization at 8-9 years (for one interquartile range (IQR) increase, adjusted odds ratio (aOR): 0.47; 95 % confidence interval (CI): 0.25-0.87 and 0.84; 0.7-1.00, respectively). Increased prenatal exposure to solar radiation was significantly associated with a lower risk of asthma at 8-9 years (for one IQR increase, aOR: 0.32; 95 % CI: 0.1-0.96). Early sunlight exposure may reduce the risk of sensitization and asthma in school-aged children, especially in those prenatally exposed to vitamin D. These findings highlight the importance of vitamin D in preventing allergic diseases in children, either through supplementation or sunlight exposure.

Shared and unique individual risk factors and clinical biomarkers in children with allergic rhinitis and obstructive sleep apnea syndrome

INTRODUCTION

Rhinitis and obstructive sleep apnea syndrome (OSAS) are different diseases, but have some similar risk factors.

OBJECTIVE

The aims of this study were to compare the risk factors and clinical biomarkers for rhinitis and OSAS in children.

METHODS

We examined 3917 children (age 4-13 years) who were enrolled in a cross-sectional study conducted in Seongnam, Korea. Their parents completed the Pediatric Sleep Questionnaire (PSQ) for evaluation of OSAS and the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire for evaluation of rhinitis. Clinical biomarkers, including total eosinophil count and neutrophil-lymphocyte ratio (NLR), were measured in a subset of these children.

RESULTS

OSAS and rhinitis had prevalences of 4.0% and 43.5%, respectively. Body mass index (P < 0.001) and prematurity (P = 0.016) were significantly associated with OSAS, but not with rhinitis. Higher parental education and income increased the risk for rhinitis, but decreased the risk for OSAS. Having more siblings and birth by Cesarean delivery decreased the risk for rhinitis, but living in a new household increased the risk for rhinitis. A short distance of the residence to a main road during pregnancy significantly increased the risk of OSAS. Males, increased exposure to mould, and firstborns had increased risk of OSAS and rhinitis. The NLR was higher in OSAS patients than in those with allergic rhinitis (P = 0.001).

CONCLUSION

OSAS and rhinitis shared some risk factors, whereas other factors had inverse association with the two disorders. These results imply that different strategies might be used for prevention of rhinitis and OSAS.