The role of meteorological parameters on childhood asthma: Identifying critical windows of susceptibility during pregnancy

Background: Despite numerous studies demonstrating a link between asthma and meteorological parameters, the role of maternal exposure in pregnancy on childhood asthma remains unknown.Objective: To investigate the association of meteorological factors during pregnancy with childhood asthma and identify key exposure windows.Methods: In central China's Changsha city, we carried out a retrospective cohort study involving 8,689 preschoolers. We used questionnaires to collect information about childhood health, personal factors, socioeconomic status (SES), and indoor environment. We considered meteorological parameters including temperature (mean, maximum, minimum), diurnal temperature variation (DTV), relative humidity, wind speed (mean, extreme), rainfall, pressure, and sunshine during early life. We investigated the links between childhood asthma and meteorological factors using logistic regression models.Results: Doctor-diagnosed asthma (D-DA) in preschoolers was associated with exposure to increased temperatures (mean, maximum, and minimum) by per IQR increment in the first month with ORs (95% CI) of 2.03 (1.21-3.40), 1.86 (1.15-3.00) and 2.08 (1.23-3.50) as well as in the first trimester with ORs of 2.40 (1.36-4.24), 2.20 (1.26-3.83) and 2.54 (1.43-4.53), respectively. D-DA was inversely related to wind speed in the first month and first two trimesters. Compared to an increased risk of D-DA when exposed to pressure in the third trimester, exposure to DTV during pregnancy, particularly in the third trimester, significantly decreased the risk. Some preschoolers with certain personal factors and high SES were more vulnerable to pre-natal meteorological exposure.Conclusion: Prenatal exposure to meteorological factors, especially high temperatures and low wind speeds in early pregnancy, contributes to childhood asthma.