Prenatal exposure to diurnal temperature variation linked to development of childhood pneumonia, Study says

Pneumonia is the leading cause of death and hospitalization among young children worldwide, but its risk factors remain unclear.

Hence, Xiangrong Zheng and associates from the Department of Pediatrics, XiangYa Hospital, Central South University, Changsha, Hunan, China conducted the present study to evaluate the effect of maternal exposure to diurnal temperature variation (DTV) during preconceptional and prenatal periods on childhood pneumonia.

The authors conducted a retrospective cohort study by case-control design for pneumonia (N = 699) and normal (N = 811) children under age of 14 who were enrolled in XiangYa Hospital, Changsha, China. 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.

The investigators obtained the data of daily DTV and the 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.

The results showed that-

a. 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).

b. A significant risk of pneumonia of DTV exposure was found during the first and second trimester of pregnancy.

c. 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.

Therefore, the authors concluded that "preconceptional (one year before conception) and prenatal exposure to DTV was significantly associated with childhood pneumonia."

We identified the first two trimesters of pregnancy as the critical time windows. Our results have a clinical significance in assessing the onset and development of pneumonia. Our study also provide a novel strategy for effective reduction and early prevention of childhood pneumonia, i.e., reducing outdoor activities among women preparing for pregnancy when the temperature changes sharply, and avoiding extra exposure to a large variation in daily temperature during pregnancy especially in the first and second trimesters, explains Zheng.