Associations of short-term ambient temperature exposure with lung function in middle-aged and elderly people: A longitudinal study in China

The short-term association of ambient temperature exposure with lung function in middle-aged and elderly Chinese remains obscure. The study included 19,128 participants from the Dongfeng-Tongji cohort's first (2013) and second (2018) follow-ups. The lung function for each subject was determined between April and December 2013 and re-assessed in 2018, with three parameters (forced vital capacity [FVC], forced expiratory volume in one second [FEV1], and peak expiratory flow [PEF]) selected. The China Meteorological Data Sharing Service Center provided temperature data during the study period. In the two follow-ups, a total of 25,511 records (average age: first, 64.57; second, 65.80) were evaluated, including 10,604 males (41.35%). The inversely J-shaped associations between moving average temperatures (lag01, lag02, lag04, and lag07) and FVC, FEV1, and PEF were observed, and the optimum temperatures in lag04 were 16.5 °C, 18.7 °C, and 16.2 °C, respectively. In lag04, every 1°C increase in temperature was associated with 14.07 mL, 9.78 mL, and 62.72 mL/s increase in FVC, FEV1, and PEF in the low-temperature zone (< the optimum temperatures), whereas 5.72 mL, 2.01 mL, and 11.64 mL/s decrease in the high-temperature zone (≥ the optimum temperatures), respectively (all P < 0.05). We observed significant effect modifications of gender, age, body mass index, body surface area, smoking status, drinking status, and physical activity on the associations (all P modification < 0.05). Non-optimal temperatures may cause lung function decline. Several individual characters and lifestyles have effect modification on the temperature effects.