Preconceptional and prenatal exposure to diurnal temperature variation increases the risk of childhood pneumonia.

BACKGROUND: Pneumonia is the leading cause of death and hospitalization among young children worldwide, but its risk factors remain unclear. OBJECTIVE: To evaluate the effect of maternal exposure to diurnal temperature variation (DTV) during preconceptional and prenatal periods on childhood pneumonia. METHODS: A retrospective cohort study by case-control design was conducted for pneumonia (N = 699) and normal (N = 811) children under age of 14 who were enrolled in XiangYa Hospital, Changsha, China from May 2017 to April 2019. Demographic data including gender, age, birth season, gestational age, parity, mode of delivery, and parental atopy were collected from the electronic medical records in the hospital system. We obtained the data of daily DTV in Changsha during 2003-2019 from China Meteorological Administration. Maternal exposure to DTV during preconceptional and prenatal periods was respectively calculated by the average of daily DTV during one year and three months before conception and entire pregnancy as well as the three trimesters. The association between maternal exposure to outdoor DTV and childhood pneumonia was analyzed by multiple logic regression model. RESULTS: We found that childhood pneumonia was significantly associated with exposure to an increase in DTV during one year before conception and entire pregnancy, with ORs (95 % CI) = 2.53 (1.56-4.10) and 1.85 (1.24-2.76). We further identified a significant risk of pneumonia of DTV exposure during the first and second trimester of pregnancy. Sensitivity analysis showed that boys were more susceptible to the effect of prenatal exposure to outdoor DTV during pregnancy particularly in the first two trimesters compared to girls. CONCLUSIONS: Preconceptional and prenatal exposure to DTV plays an important role in development of childhood pneumonia, especially during the first and second trimesters of pregnancy.

Preconceptional and prenatal exposure to air pollution increases incidence of childhood pneumonia: A hypothesis of the (pre-)fetal origin of childhood pneumonia.

BACKGROUND: Increasing evidence has linked childhood pneumonia with early exposure to ambient air pollution. However, the impact of exposure to air pollutants before birth is unclear. OBJECTIVE: To further clarify whether exposure to a particular pollutant during preconceptional and prenatal periods, may pose a higher risk of developing childhood pneumonia. METHODS: This case-control cohort study consisted of 1510 children aged 0-14 years in Changsha, China between 2017 and 2019. Data of children's history of pneumonia and blood biomarkers were obtained from the XiangYa Hospital records. Each child's exposure to air pollutants, including nitrogen dioxide (NO2), sulfur dioxide (SO2), and particulate matter with an aerodynamic diameter ≤ 10 µm (PM10), was calculated using data from ten air pollution monitoring stations. A multivariate logistic regression model was used to quantify the relationship between childhood pneumonia and exposure to ambient air pollution during the preconceptional and prenatal periods. RESULTS: Childhood pneumonia was significantly associated with preconceptional and prenatal exposure to the industrial-related air pollutant, SO2, for 1 year before conception, for 3 months before conception and for the entire pregnancy, with ORs(95% CI)= 4.01(3.17-5.07), 4.06(3.29-5.00) and 6.51(4.82-8.79). Also, children who were sick with pneumonia had higher white blood cell and neutrophil counts, and children with low eosinophil count or hemoglobin are likely to get pneumonia. Sensitivity analysis showed that boys, and children in high temperature area were susceptible to the effect of both preconceptional and prenatal exposure to industrial SO2. CONCLUSION: Preconceptional and prenatal exposure to industrial-related air pollution plays a significant role in the incidence and progression of childhood pneumonia, supporting the hypothesis of "(pre-)fetal origin of childhood pneumonia".