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.

Unsupervised identification of cardiometabolic profiles among adolescents: findings from the PARIS birth cohort study.

Metabolic syndrome (MetS) is known as a risk factor in cardiometabolic morbidity but there is no consensus on its definition for teenagers. We aimed to identify cardiometabolic health profiles and which parameters best discriminate them. K-means partitioning identified cardiometabolic profiles by sex using data on health measurements of 530 adolescents from the PARIS birth cohort. A discriminant analysis was performed. Cardiometabolic risk score and handgrip strength were also measured. Depending on definitions, MetS prevalence ranged from 0.2% to 1.3%. Two profiles were identified for the entire group and by sex: "healthy" and "at cardiometabolic risk." Weight and waist-to-height ratio or waist circumference explained more than 87% of the variance in the profile differentiation. The "at cardiometabolic risk" profiles included adolescents with overweight, a waist-to-height ratio over 0.5, and prehypertension. They had higher cardiometabolic risk scores and parents who were more likely to be overweight and have cardiometabolic diseases themselves. They also had higher birthweights, earlier adiposity-rebound and puberty ages, and lower relative handgrip strength.  Conclusion: The two profiles identified, based on cardiometabolic health, were associated with early indicators and handgrip strength. Results suggest that the waist-to-height ratio is a useful clinical tool for screening individuals at cardiometabolic risk and who therefore require clinical follow-up. What is Known: • Although there is a need for tools to assess cardiometabolic health during adolescence, there is no consensus on the definition of metabolic syndrome for this age group. What is Knew: • The findings suggest that waist-to-height ratio can serve as a simple and valuable clinical tool for screening individuals at cardiometabolic risk who may require clinical monitoring for early prevention of cardiovascular diseases.