Seasonality of suicide: a multi-country multi-community observational study

• Type of Material: Article
• Authors: J. Yu, Korea Advanced Institute of Science & Technology; D. Yang, Korea Advanced Institute of Science & Technology; Y. Kim, University of Tokyo; M. Hashizume, University of Tokyo; A. Gasparrini, London School of Hygiene & Tropical Medicine; B. Armstrong, London School of Hygiene & Tropical Medicine; Y. Honda, University of Tsukuba; A. Tobias, Spanish Council of Science Research; F. Sera, London School of Hygiene & Tropical Medicine; A.M. Vicedo-Cabrera, University of Bern; H. Kim, Seoul National University; C. Iniguez, University of Valencia; E. Lavigne, University of Ottawa; M.S. Ragettli, Swiss Tropical and Public Health Institute; Noah Scovronick, Emory University; F. Acquaotta, University of Torino; B. Chen, National Health Research Institutes; Y.L. Guo, National Health Research Institutes; M. de Sousa Zanotti Stagliori Coelho, University of Sao Paulo; P. Saldiva, University of Sao Paulo; A. Zanobetti, Harvard TH Chan School of Public Health; J. Schwartz, Harvard TH Chan School of Public Health; M.L. Bell, Yale University; M. Diaz, National Institute of Public Health; C. de la Cruz Valencia, National Institute of Public Health; I. Holobaca, Babes Bolay University; S. Fratianni, University of Torino; Yeonseung Chung, Korea Advanced Institute of Science & Technology
• Language: English
• Date: 2020-01-01
• Publisher: CAMBRIDGE UNIV PRESS
• Publication Version: Final Published Version
• Copyright Statement: © The Author(s) 2020
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1017/S2045796020000748
• Title of Journal or Parent Work: EPIDEMIOLOGY AND PSYCHIATRIC SCIENCES
• Volume: 29
• Start Page: e163
• End Page: e163
• Grant/Funding Information: JY, DY and YC were supported by a Senior Research grant (2019R1A2C1086194) from the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT (Information and Communication Technologies) and Government-wide R&D Fund project for Infectious Disease (HG18C0025). YK was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Number JP19K17104 in Japan. AG and FS were supported by the Medical Research Council UK (Grant ID: MR/R013349/1) and Natural Environment Research Council (Grant ID: NE/R009384/1). NS was supported by the NIEHS-funded HERCULES Center (P30ES019776).
• Keywords: Psychiatry; seasonality; heterogeneity; suicide; GENDER; SUNSHINE; VIOLENT SUICIDE; Life Sciences & Biomedicine; SEX; ASSOCIATION; Climate; AGE; TIME; TEMPERATURE; socioeconomic; Science & Technology; FINLAND
• Research Categories: Psychology, Clinical; Psychology, Social; Sociology, Public and Social Welfare

Abstract

AimsWe aimed to investigate the heterogeneity of seasonal suicide patterns among multiple geographically, demographically and socioeconomically diverse populations.MethodsWeekly time-series data of suicide counts for 354 communities in 12 countries during 1986-2016 were analysed. Two-stage analysis was performed. In the first stage, a generalised linear model, including cyclic splines, was used to estimate seasonal patterns of suicide for each community. In the second stage, the community-specific seasonal patterns were combined for each country using meta-regression. In addition, the community-specific seasonal patterns were regressed onto community-level socioeconomic, demographic and environmental indicators using meta-regression.ResultsWe observed seasonal patterns in suicide, with the counts peaking in spring and declining to a trough in winter in most of the countries. However, the shape of seasonal patterns varied among countries from bimodal to unimodal seasonality. The amplitude of seasonal patterns (i.e. the peak/trough relative risk) also varied from 1.47 (95% confidence interval [CI]: 1.33-1.62) to 1.05 (95% CI: 1.01-1.1) among 12 countries. The subgroup difference in the seasonal pattern also varied over countries. In some countries, larger amplitude was shown for females and for the elderly population (≥65 years of age) than for males and for younger people, respectively. The subperiod difference also varied; some countries showed increasing seasonality while others showed a decrease or little change. Finally, the amplitude was larger for communities with colder climates, higher proportions of elderly people and lower unemployment rates (p-values < 0.05).ConclusionsDespite the common features of a spring peak and a winter trough, seasonal suicide patterns were largely heterogeneous in shape, amplitude, subgroup differences and temporal changes among different populations, as influenced by climate, demographic and socioeconomic conditions. Our findings may help elucidate the underlying mechanisms of seasonal suicide patterns and aid in improving the design of population-specific suicide prevention programmes based on these patterns.