Early exposure to sunlight and allergic morbidity: The PARIS birth cohort
Sci Total Environ. 2024 Apr 16:172543. doi: 10.1016/j.scitotenv.2024.172543 PDF is behind a paywall
Léa Lefebvre 1, Hélène Amazouz 2, Fanny Rancière 3, Isabelle Momas 4
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.
Vitamin D Life – Season of Birth category contains:
Season of birth is a good proxy for Vitamin D (for people far from the Equator)
Statistisically significant, but rarely greater than 20% change
Some health problems need Vitamin D in 2 or 3 trimesters, so are not associated with season
Perhaps some people in born in poor season will need more vitamin D all of their lives
Some Season of Birth studies
- Season of birth associated with many health problem (UK Biobank) – Nov 2020
- Preterm birth varies with season: 25 percent more likely if conception in autumn – Feb 2022
- Little sun in first trimester, 2.9 X more likely to have learning disabilities – June 2019
- UV at time of conception associated with Vitamin D Receptor activation 65 years later – Sept 2017
- Autoimmune Addison's Disease – increased risk if born in Dec or Jan – Nov 2016
- Schizophrenia increased 40 percent for Spring births after Danes stopped vitamin D fortification – April 2014
- Season of birth associated with Pneumonia (10 %) and Multiple Sclerosis (30 %) – May 2013
- Majority of Season of Birth health problems should vanish if take Vitamin D
100K monthly, or 50K bi-weekly, or 4K daily