Protective effects of low temperature on the risk of hospitalization for mental and behavioral disorders: a time series study

The high incidence of mental illness worldwide is a substantial economic burden on society. Temperature and the occurrence of mental and behavioral disorders (MDs) seem to have a relationship, but this has not been widely researched. Therefore, this study aimed to investigate the effect of temperature on the hospitalization rate of patients with MDs in a temperate monsoon climate region of northern China. Patients with MDs hospitalized in the Mental Health Center of Hebei Medical University and Psychology Department in The third Hospital of Shijiazhuang, China, from January 2014 to December 2019 were included in the study. The delayed exposure – response relationship between temperature and the number of hospitalized MDs patients was analyzed using a quasi-Poisson generalized additive model combined with a distributed lag nonlinear model. With the reference of 15.3°C (temperature with the minimum hospitalizations), the single lag effect of low temperature (−2°C, 10th percentile) increased the hospitalization of patients with MDs, while the cumulative effect decreased the risk of hospitalization for some MD subtypes; it was an acute protective effect. The single and cumulative lag effect of high temperature statistically increased the hospitalization rates of patients with MDs. The optimum temperature for each subtype was different, and the males and the younger age group were more susceptible to high temperatures. Low temperature has an acute protective effect on the hospitalization of patients with MDs. In comparison, high temperature increases hospitalization rates. Men and younger people are more affected by temperature, which provides early warning and health intervention measures for patients with corresponding temperature changes.

全球范围内精神疾病的高发病率给社会带来了沉重的经济负担。气温与精神与行为障碍（Mental and Behavioral Disorders, MDs）的发生似乎存在关联，但相关研究尚未得到广泛开展。为此，本研究旨在探究中国北方温带季风气候区域内，气温对精神与行为障碍患者住院率的影响。本研究纳入了2014年1月至2019年12月期间，在中国河北医科大学精神卫生中心及石家庄市第三医院心理科住院的精神与行为障碍患者。本研究采用准泊松广义加性模型（quasi-Poisson generalized additive model）结合分布滞后非线性模型（distributed lag nonlinear model），分析了气温与精神与行为障碍住院患者人数之间的延迟暴露-反应关系。以15.3℃（住院人数最少对应的气温）为参照，低温（-2℃，即温度分布的10分位数）的单滞后效应会提升精神与行为障碍患者的住院率；而其累积效应则可降低部分亚型患者的住院风险，表现为急性保护作用。高温的单滞后效应与累积滞后效应均在统计学上显著提升了精神与行为障碍患者的住院率。不同精神与行为障碍亚型的最佳温度阈值存在差异，男性及年轻群体对高温更为敏感。低温对精神与行为障碍患者的住院风险具有急性保护作用，而高温则会提升其住院率；男性与年轻群体受气温影响更为显著，本研究结果可为对应气温变化下的高危人群提供早期预警及健康干预依据。