[Impact of ambient air pollution on hospital visits for mental and behavioral disorders among residents in an industrial area in Henan Province from 2016 to 2021]

Abstract

Objective: To explore the impact of air pollution on hospital visits for mental and behavioral disorders among residents in an industrial area in Henan Province from 2016 to 2021. Methods: Daily outpatient visits data for mental and behavioral disorders, as well as air pollutants and meteorological data during the same period, were collected from Angang General Hospital in Angang Industrial Zone at Anyang City between January 2016 and December 2021. A generalized additive model was used for time-series analysis to examine the relationship between daily average concentrations of nitrogen dioxide (NO₂), sulfur dioxide (SO₂), fine particulate matter (PM_2.5), inhalable particulate matter (PM₁₀), carbon monoxide (CO), and ozone (O₃) with a lag of 0 to 7 days on the number of visits for mental and behavioral disorders among residents. The single-day lag effect (lag0-lag7 d) and cumulative lag effect (lag01-lag07 d) were analyzed. The smooth cubic spline function was used to fit the exposure-response relationship, and subgroup analysis was performed according to different genders, seasons and ages. Results: A total of 26 268 hospital visits for mental and behavioral disorders were collected from the industrial area between 2016 and 2021. The daily average concentrations of SO₂, NO₂, PM_2.5, PM₁₀, and CO were (27.50±27.33), (43.11±18.33), (73.87±60.30), (134.01±83.81) μg/m³, and (1.72±1.03) mg/m³, respectively. The daily maximum 8-hour average concentration of O₃ was (82.18±53.70) μg/m³. After controlling for long-term trends, temperature, relative humidity, day of the week effect, and holiday effects, the generalized additive model analysis showed that NO₂ had a statistically significant impact on the hospital visits for mental and behavioral disorders at lag0 d, lag2 d and lag01-lag05 d and CO had a statistically significant impact at lag0-lag3 d and lag01-lag06 d (all P<0.05). NO₂ at lag02-lag04 d and CO at lag0-lag2 d and lag01-lag04 d had statistically significant effects on the visits for neurasthenia (both P<0.05). The impacts of NO₂ at lag03-lag04 d, PM_2.5 at day lag3 d and lag03-lag04 d, PM₁₀ at lag3 d and lag03 d, and CO at lag3 d and lag01-lag05 d on visits for generalized anxiety disorder were also statistically significant (all P<0.05). After false discovery rate (FDR) correction, it was shown that for every 10 μg/m³ increase in NO₂ and every 0.1 mg/m³ increase in CO, the percentage increase in visits for mental and behavioral disorders and its 95% confidence interval (95%CI) were 3.38% (0.95%-5.87%) and 0.78% (0.38%-1.17%), respectively. For every 0.1 mg/m³ increase in CO, the visits for neurasthenia increased by 0.78% (0.27%-1.29%). For every 10 μg/m³ increase in PM_2.5 and every 0.1 mg/m³ increase in CO, the visits for generalized anxiety disorder increased by 1.07% (0.46%-1.68%) and 1.17% (0.37%-1.97%), respectively (adjusted P<0.05). There was a linear exposure-response relationship between NO₂ and CO and the hospital visits for mental and behavioral disorders, CO and the hospital visits for neurasthenia, and CO and PM_2.5 and the hospital visits for generalized anxiety disorder (P<0.05 for the overall association test and P>0.05 for the non-linearity test). Stratified analysis showed that air pollutants had an impact on male patients with neurasthenia, female patients with generalized anxiety disorder, individuals aged<45 years with mental and behavioral disorders, and individuals aged≥65 years with generalized anxiety disorder. The impact of air pollutants was greater during the cold season or winter. Conclusion: Exposure to air pollution can increase hospital visits for mental and behavioral disorders among residents in industrial areas, with a higher risk among those aged<45 years old and during the cold season.