title: Association among number, order and type of siblings and adolescent mental health at age 12.
abstract: BACKGROUND
  Although the sibling relationship is a unique one, the effects of the number and type of siblings on mental health among adolescents have not been reported.
  
  
  METHODS
  Japanese children (total, 9276; boys, 4654; girls, 4622), all 12 years old, and from the Japanese Toyama Birth Cohort Study, were followed up until 2002. Subject self-reported mental health was obtained from the Japanese version of the Dartmouth Primary Care Co-operative Project (COOP) charts. The associations between number and type of siblings and self-reported mental health were examined.
  
  
  RESULTS
  There was a significant difference in mental health between different sibling pairs, with brother pairs and brother/sister pairs having a positive effect on adolescent mental health, compared with those in sister pairs. Girls with brothers had better self-reported mental health than those without. The adjusted OR of good mental health was 1.44 (95%CI:1.00-2.08) for those with an older brother and 1.67 (95%CI: 1.17-2.38) for those with a younger brother compared with those without. Boys with a younger sister had a higher OR of good self-reported health than those without (OR, 1.62; 95%CI: 1.08-2.43).
  
  
  CONCLUSIONS
  Children with siblings had better mental health status than those without, which has practical implications for Asian countries and worldwide considering the declining fertility.
authors: Institute of Reproductive and Child Health, Ministry of Health Key Laboratory of Reproductive Health, Department of Epidemiology and Biostatistics, School of Public Health, Peking University.|Department of Epidemiology and Health Policy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
authors: Jufen
authors: J
authors: Liu
authors: Department of Epidemiology and Health Policy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
authors: Michikazu
authors: M
authors: Sekine
authors: Department of Epidemiology and Health Policy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
authors: Takashi
authors: T
authors: Tatsuse
authors: Department of Epidemiology and Health Policy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
authors: Yuko
authors: Y
authors: Fujimura
authors: Department of Epidemiology and Health Policy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
authors: Shimako
authors: S
authors: Hamanishi
authors: Institute of Population Research, Peking University, Beijing, China.
authors: Xiaoying
authors: X
authors: Zheng
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology / Q000523:psychology*; D008603:Mental Health; D012189:Retrospective Studies; D057566:Self Report; D012737:Sex Factors; D012801:Sibling Relations; D035781:Siblings / Q000523:psychology*
keywords: birth cohort; mental health; quality of life; sibling