title: Birthdays are associated with an increased risk of suicide in Japan: Evidence from 27,007 deaths in Tokyo in 2001-2010.
abstract: Previous research has produced conflicting findings concerning whether birthdays are associated with an increased risk of suicide. This study examined the association in Tokyo, Japan.
  
  
  
  Suicide data (ICD-10 codes X60-X84) for the period 2001-2010 were obtained from the Japanese Ministry of Health, Labour and Welfare. A time-stratified case-crossover design was used with conditional logistic regression analysis being performed to estimate within-subject 'birthday exposures' while controlling for meteorological conditions and public holidays.
  
  
  
  There were 27,007 suicides in the study period. For males the 5 days before the birthday and the week after the birthday were associated with significantly higher odds for suicide with the odds ratio being highest on the actual birthday (OR =1.677, 95% CI: 1.294, 2.172). For females, significantly higher odds for completed suicide were observed 7-11 days before the birthday. Stratified analyses showed different at risk time patterns among men from different age groups, and that married men had higher odds for suicide on, and for the 4 days before and in the 2 weeks after their birthday.
  
  
  
  We lacked detailed information on suicides which would have enabled a better understanding of the observed associations.
  
  
  
  Birthdays are associated with an increased risk for suicide in Tokyo, Japan. Health professionals who work with individuals at risk of suicide should be made aware that birthdays are associated with an elevated suicide risk. This information should also be communicated in wider suicide prevention campaigns.
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; The Stockholm Centre for Health and Social Change (SCOHOST), Södertörn University, Huddinge 141 89, Sweden. Electronic address: andrew.stickley@sh.se.
authors.forename: Andrew
authors.initials: A
authors.lastname: Stickley
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
authors.forename: Chris Fook
authors.initials: CF
authors.lastname: Sheng Ng
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Inoue
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Aki
authors.initials: A
authors.lastname: Yazawa
authors.affiliation: Parc Sanitari Sant Joan de Déu, Universitat de Barcelona, Fundació Sant Joan de Déu, Dr Antoni Pujadas, 42, Sant Boi de Llobregat, Barcelona 08830, Spain; Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Monforte de Lemos 3-5 Pabellón 11, Madrid 28029, Spain.
authors.forename: Ai
authors.initials: A
authors.lastname: Koyanagi
authors.affiliation: Center for Suicide Prevention, National Institute of Mental Health, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira, Tokyo 187-8553, Japan.
authors.forename: Manami
authors.initials: M
authors.lastname: Kodaka
authors.affiliation: School of Social Work, University of Maryland, Baltimore, 525 W Redwood St, Baltimore, MD 21201, USA.
authors.forename: Jordan E
authors.initials: JE
authors.lastname: DeVylder
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Chiho
authors.initials: C
authors.lastname: Watanabe
mesh_terms: D000328:Adult; D000368:Aged; D018592:Cross-Over Studies; D005260:Female; D006693:Holidays; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D012306:Risk; D012737:Sex Factors; D013405:Suicide / Q000706:statistics & numerical data*; D014041:Tokyo; D000092864:Suicide Prevention
keywords: Birthday; Japan; Suicide; Suicide prevention