Effects Of Heat Waves On Residents’ Mental Health And The Relative Factors In Jinan

[Background]Climate change is likely the biggest global health threat of the21st century. The surface temperature of the earth has significantly warmed in the past few decades and it has been accelerating at a rate far greater than has been projected (Intergovernmental Panel on Climate Change, IPCC,2007). Heat wave, as a global environment problem, is usually characterized by extreme high temperatures and long durations, to which humans are unable to adjust to such extreme conditions. The frequency and intensity of heat waves have been continuously increasing as global temperatures increases.Mental illness has already caused a significant burden on the public health system. In2007, the Fourth Intergovernmental Panel on Climate Change (IPCC) assessment clearly reported a wide range of adverse health effects caused by climate change, which alludes to the fact that many critical effects are psychological. More frequent and insensitive extreme heat events have been projected based on climate change modeling. Given the large and increasing health burden of mental illnesses in both developed and developing countries, it is of significance to have a better understanding of the association between heat waves and mental illnesses. The impacts of heat waves on mortality and morbidity from mental illnesses, the characteristics of the impacts and the potential risk factors have been reviewed. Implications on adaptive measures and further studies have been provided to support evidence-based public health decision-making to reduce future heat-related health burden of mental illnesses.[Objective] To explore the effects of heat waves on daily hospital visits for mental illness (ICD-10:F00-F99) in summer of2010in Jinan, Shandong, China. And the factors affected the morbidity of mental health also to be investigated. The purposes are to analyze the association between heat waves and mental health, and to discuss the potential risk factors that make the subgroups of mental illnesses at higher risk during the heat waves.[Methods]The residents in Jinan are taken as the study’s population. The information of mental illness cases were extracted from the mental health center in Shandong province. And the meteorological factors (including mean daily temperature and daily relative humidity, etc.) during the study’s period were collected from China meteorological data sharing service system.Case-crossover study was used to evaluate the relationship between heat waves from Jun to Aug and daily hospital visits for mental illness in Jinan of2010. In the unidirectional retrospective case-crossover study and bidirectional case-crossover study, based on the theory of the case-control study, we choose the index period and the referent period, and then apply conditional logistic regression to get the odds ratio of heat waves exposure. And the results of the bi-directional case-crossover study were compared with unidirectional retrospective case-crossover study. Case control study was used to analyze the potential risk factors that make the subgroups of mental illnesses at higher risk during the heat waves.[Results]There were four heat waves in the investigation duration (Jun1to Aug30,2010), and the daily hospital visits for mental illness during the heat wave period and non-heat wave period are3573and15996respectively. And the OR values for the four heat waves of the two designs were2.224(95%CI,1.980～2.498) and2.439(95%CI,2.192～2.713);2.940(95%CI,2.444～3.536) and2.940(P5%CI,2.575～3.358);3.165(95%CI,2.657～3.771) and3.436(95%CI,3.013～3.918);3.019(95%CI,2.476～3.681) and3.039(95%C, 2.536～3.642). And the best lag-phase were3,2,3and2days, respectively.The potential risk factors that make the subgroups of mental illnesses at higher risk during the heat waves were:age, occupation, address, marital status. That is the elderly over65, people living in urban areas or divorced increase the risk of mental illness during the heat wave period; and compared to the other occupational population, farmers are at higher risk during on extremely hot weather.[Conclusion]Significant increase was seen for daily hospital visits of mental illness during the heat waves in Jinan of2010, and there was lag-effect usually. Age, occupation, address and marital status are all associated with an increased risk for the mental illnesses during the heat waves in our study.