Early exposure to ambient temperature is associated with newborn lung function with sex-specific effects

BACKGROUND AND AIM: Despite recognition of climate change, little is known on how ambient temperature may affect fetal development and child respiratory health. This study investigated the effect of prenatal and early postnatal exposure to ambient temperature on newborn lung function in France. METHODS: Prenatal and early postnatal mean temperature and temperature variability at the mother’s residence were estimated based on a validated spatiotemporally resolved exposure model in 343 mother–child pairs from the SEPAGES cohort. Newborn lung function was assessed at two months during unsedated sleep with tidal breathing and multiple breath washout test. Associations of ambient temperature with newborns lung function were analyzed using adjusted Distributed Lag Non-linear Models (DLNM) for the whole cohort and then stratified by sex. Both chronic (the first 35 gestational weeks and the 4 weeks after birth) and acute (the 7 days before the respiratory tests) exposures were investigated. RESULTS: Among girls, chronic exposure to severe cold (the 5th percentile vs the median temperature) was robustly related to lower Functional Residual Capacity (FRC), lower tidal volume and higher respiratory rate. Chronic exposure to severe heat (the 95th percentile vs the median temperature) in girls was related to lower FRC and higher respiratory rate. Most of the significant windows of vulnerability to ambient temperature occurred between the second trimester of pregnancy and the first weeks of life. CONCLUSIONS: Prenatal and early postnatal exposure to severe cold or heat may alter lung function among infants, especially in girls. Lung volumes appeared more specifically affected than airflows. Considering children and adults respiratory health are closely linked, long-term consequences may be substantial. KEYWORDS: Ambient temperature; Climate change; DLNM; Infants; Lung function; Prenatal/Postnatal exposure; Restrictive lung disease