Short-term ozone exposure and schizophrenia hospitalization risk: temperature modifying effect and greenspace...

Few studies have examined the association between rising ozone (O₃) pollution and schizophrenia (SCZ) hospitalizations, or whether temperature and greenness influence this relationship. We conducted a time-stratified case-crossover study utilizing the 160,551 SCZ hospitalizations data across Anhui Province, China, from 2017 to 2020. Maximum daily 8-h average O₃ concentrations and mean temperature of each patient were estimated by residential addresses. Conditional logistic regression model was used to investigate the association between O₃ and SCZ hospitalization and to assess the relationship across different temperature levels. Restricted cubic spline was used to assess the mitigating effect of residential greenspace. SCZ hospitalization risk increased by 3.9 % (OR = 1.039, 95 % CI: 1.030-1.046), every 10 μg/m³ increases in O₃ under high temperature level, although not found association between O₃ exposure and SCZ hospitalizations overall. Furthermore, subgroup analyses found that the adverse effect was greater in patients aged ≥45 years than <45 years (P = 0.025). Encouragingly, greenspace could mitigate the adverse effect (P-trend = 0.014), specifically in the North Anhui Plain (P-trend = 0.004). These findings highlight the harmful effect of O₃ pollution on SCZ hospitalizations under climate warming scenarios and imply greenspace could be an effective protective measure.