Acute effects of ambient temperature on lung function of a panel of school children living in Dhaka, Bangladesh.

Introduction: Short-term exposure to ambient temperature plays a significant role in human health. However, studies examining ambient temperature and lung function are scarce in locations with a tropical environment. To address this research gap, the current study investigated the effects of short-term ambient temperature on lung function in children and seasonal variation in this association in Dhaka, Bangladesh.

Methods: The study was conducted in three schools located in three cities inside and around Dhaka. Repeated lung function measurements were obtained from a panel of 315 school children (including 86 asthmatic children) aged 9-16 years in 2013. Linear mixed-effects models adjusted for potential confounders were used to examine the effect of ambient temperature on lung function.

Results: Short-term exposure to low ambient temperature was associated with a significant decrement in children's lung function. For each 1 °C decrease in daily mean temperature at cumulative lag of the current and previous day, lung function parameter values were -3.02% (95% CI, -1.69 to -4.35) for peak expiratory flow (PEF), and -1.48% (95% CI, -0.75 to -2.22) for forced expiratory volume within 1 s (FEV1). A significant seasonal variation was also observed in these associations, as the estimated adverse effects of decrease in daily mean temperature on lung function measures were primarily evident in winter.

Discussion: This study suggests that short-term ambient exposure to decrease in temperature adversely affect lung function. A significant seasonal modification in the association between temperature and lung function was also observed for these children living in an environment with a tropical climatic condition as the adverse effect of decrease in ambient temperature was primarily observed in winter than in summer.