Non-optimum ambient temperature may decrease pulmonary function: A longitudinal study with intensively repeated...

Area of Science:

• Environmental Health
• Pulmonary Medicine
• Epidemiology

Background:

• Ambient temperature is an under-recognized environmental risk factor for asthma.
• The impact of temperature fluctuations on pulmonary function in asthma patients requires further investigation.

Purpose of the Study:

• To investigate the association between non-optimum ambient temperature and pulmonary function in adult asthma patients.
• To explore the duration and characteristics of temperature effects on respiratory health.

Main Methods:

• A longitudinal study involving 4,992 adult asthmatic patients across 25 Chinese cities from 2017-2020.
• Daily morning and evening pulmonary function tests were conducted.
• Linear mixed-effects and distributed lag non-linear models analyzed temperature-pulmonary function relationships.

Main Results:

• An inverse J-shaped relationship was observed between ambient temperature and pulmonary function.
• Extreme cold (-9.4°C) significantly decreased FEV1, PEF, and FVC, with effects lasting up to 72 hours.
• Extreme heat (34.2°C) also reduced pulmonary function, though to a lesser extent than cold.
• Vulnerable populations included males, overweight individuals, and the elderly; cold effects were more pronounced in southern China and areas lacking central heating.

Conclusions:

• Both extreme low and high ambient temperatures adversely affect pulmonary function in adult asthma patients.
• The impact of temperature on lung function can persist for up to three days, with cold temperatures posing a greater risk.