Risk of adolescent offspring's completed suicide increases with prior history of their same-sex parents' death by suicide.

BACKGROUND: To investigate the risk of completed suicide in offspring during adolescence in relation to prior history of the same-sex parent's death by suicide and other causes. METHOD: A total of 500 adolescents who died by suicide at age 15-19 years between 1997 and 2007 were identified from the Taiwan Mortality Registration (TMR). For each case, 30 age- and time-matched controls were selected randomly from all adolescents registered in the Taiwan Birth Registry (TBR). A multivariate conditional logistic regression model was used to assess the risk of adolescent completed suicide in relation to their same-sex parent. RESULTS: Adolescent suicide risk was positively associated with both paternal [odds ratio (OR) 5.38, 95% confidence interval (CI) 2.17-13.33] and maternal suicide (OR 6.59, 95% CI 1.82-23.91). The corresponding risk estimates associated with paternal and maternal deaths from non-suicidal causes were much lower, at 1.88 and 1.94 respectively. The risk of suicide in male adolescents was significantly associated with prior history of paternal death by suicide (OR 8.23, 95% CI 2.96-22.90) but not of maternal death by suicide (OR 3.50, 95% CI 0.41-30.13). On the other contrary, the risk of suicidal death in female adolescents was significantly associated with prior history of maternal suicide (OR 9.71, 95% CI 1.89-49.94) but not of paternal suicide (OR 2.42, 95% CI 0.30-19.57). However, these differences did not reach statistical significance. CONCLUSIONS: Although limited by sample size, our study indicates that adolescent offspring suicidal death is associated with prior history of their same-sex parent's death by suicide.

Effect modification by parental education on the associations of birth order and gender with learning achievement in adolescents.

BACKGROUND: A child's gender and ordinal position within a family have varied implications on his or her personality and cognitive development. However, little is known about whether or not parental educational level may moderate the effects of birth order and gender. METHODS: Basic Competence Test (BCT) scores of 290,588 young adolescents aged 15-16 years in Taiwan were analysed. Parental educational level was calculated as the highest educational attainment of the subjects' parents. The multiple linear regression model was used to assess the modification effects of parental educational levels on the associations of interest. RESULTS: After controlling for covariates, we noted a clear inverse relationship between birth order and BCT scores in Mandarin, Mathematics and Science. Additionally, boys had significantly lower mean scores in Mandarin, but had significantly higher mean scores in both Mathematics and Science. We also found the significant interactive effects of birth order, gender and parental educational attainment on BCT scores, in which the birth order and gender effects were more evident in higher-educated families than in lower-educated ones. CONCLUSIONS: This large cohort study confirmed that both birth order and gender may pose independent influences on BCT scores; moreover, such influences are significantly modified by parental educational attainment.