Maternal age at child birth, birth order, and suicide at a young age: a sibling comparison

Prenatal Antidepressant Exposure and Risk of Depression and Anxiety Disorders: An Electronic Health Records-Based Cohort Study

OBJECTIVE

To examine the associations of serotonergic antidepressant exposure during pregnancy with the risk of depression and anxiety disorders in offspring.

METHOD

The Mayo Clinic Rochester Epidemiology Project medical records-linkage system was used to study offspring born to mothers who were prescribed a selective serotonin reuptake inhibitor or serotonin-norepinephrine reuptake inhibitor (S/NRI users, n = 837) during pregnancy (1997-2010). Cox regression models were used to calculate hazard ratios to examine associations of S/NRIs with diagnosed depression and anxiety, defined based on a review of medical records by 2 board-certified psychiatrists, vs no maternal antidepressant use during pregnancy (nonusers, n = 863) and maternal antidepressant use in the year prior to pregnancy (former users, n = 399) as control groups.

RESULTS

After all adjustments for covariates, children born to S/NRI users during pregnancy did not differ in onset of depression or anxiety from the children of nonusers (adjusted hazard ratio = 1.00, 95% CI [0.74, 1.85]) or former users (adjusted hazard ratio = 0.94, 95% CI [0.69, 1.27]). These associations were similar when exposure was limited only to selective serotonin reuptake inhibitors.

CONCLUSION

The results suggest that higher rates of childhood and adolescent depression or anxiety conditioned on maternal S/NRI use in pregnancy are more likely to be driven by maternal depression or underlying propensity for depression rather than direct pharmacological effects of in utero S/NRI exposure.

The developmental origins of suicide mortality: a systematic review of longitudinal studies

Suicide prevention efforts generally target acute precipitants of suicide, though accumulating evidence suggests that vulnerability to suicide is partly established early in life before acute precipitants can be identified. The aim of this systematic review was to synthesize evidence on early life vulnerability to suicide beginning in the prenatal period and extending through age 12. We searched PubMed, Embase, PsycNet, Web of Science, Scopus, Social Services Abstracts, and Sociological Abstracts for prospective studies published through January 2021 that investigated early life risk factors for suicide mortality. The search yielded 13,237 studies; 54 of these studies met our inclusion criteria. Evidence consistently supported the link between sociodemographic (e.g., young maternal age at birth, low parental education, and higher birth order), obstetric (e.g., low birth weight), parental (e.g., exposure to parental death by external causes), and child developmental factors (e.g., exposure to emotional adversity) and higher risk of suicide death. Among studies that also examined suicide attempt, there was a similar profile of risk factors. We discuss a range of potential pathways implicated in these associations and suggest that additional research be conducted to better understand how early life factors could interact with acute precipitants and increase vulnerability to suicide.

Birth order and sickness absence: Register-based evidence from Finland

BACKGROUND

In working ages, sickness absence is strongly related to persons' health condition. We studied how birth order was associated with receipt of sickness allowance, distinguishing between mental disorders, musculoskeletal disorders and injuries.

METHODS

A follow-up study based on the entire Finnish population was conducted for sibling groups born 1969-1982, in which each sibling was observed from age 35 years in the period 2004-2018. Focus was on within-family variation in first-time sickness allowance receipt.

RESULTS

Results of stratified Cox regressions revealed that each increase in birth order was associated with a slightly higher risk of sickness absence from any cause. For mental disorders, associations were stronger; the hazard ratio as compared to first borns was 1.03 (95% CI: 0.98-1.08) of second borns, 1.10 (0.99-1.22) of third borns, and 1.52 (1.25-1.85) of fourth or higher borns. Corresponding numbers for musculoskeletal disorders were 1.12 (1.07-1.17), 1.19 (1.09-1.30) and 1.15 (0.96-1.38), and for injuries 1.06 (1.01-1.12), 1.09 (1.21-1.14) and 0.96 (0.77-1.20), respectively.

CONCLUSIONS

Birth order effects were generally stronger for women than men, and to some extent influenced by educational level, occupation, income, and family composition. Possible latent mechanisms behind the associations may relate to within-family dynamics at childhood.

Birth order and health events attributable to alcohol and narcotics in midlife: A 25-year follow-up of a national Swedish birth cohort and their siblings

Higher birth order is associated with increased risks of adverse health outcomes attributable to alcohol or narcotics in adolescence, but it remains unclear whether these observed birth order effects are also present in midlife. Drawing on a national Swedish cohort born in 1953 and their siblings, we estimate associations between birth order and alcohol- or narcotics-attributable hospitalization or death with a 25-year follow-up to assess whether birth order differences are observed during this life course period. Health events attributable to alcohol or narcotics use were identified using the Swedish National Patient and Cause of Death registers, respectively. We apply Cox proportional hazards models to estimate average birth order differences in hazards for alcohol- or narcotics-attributable hospitalization or death between ages 30 and 55. We estimate birth order differences between families, and use two fixed-effects approaches to estimate birth order differences within families and within families of the same type. Bivariate results indicate increased hazards for both outcomes with higher birth order; however, these results are no longer observed after adjustment for familial background characteristics in all models. Our results thereby show limited evidence for birth order differences in midlife. This study highlights that shared factors within the family of origin may be stronger predictors of adverse health outcomes attributable to substance use among siblings during this life course period. Future research should disentangle the contributions of the social environment within the family of origin for adverse health outcomes attributable to alcohol or narcotics among siblings.

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We estimate birth order differences for alcohol or narcotics use outcomes between ages 30-55.

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Birth order differences are not observed for alcohol- or narcotics-attributable events in midlife.

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Family background characteristics may be stronger predictors of these outcomes.

Prenatal origins of suicide mortality: A prospective cohort study in the United States

Most suicide research focuses on acute precipitants and is conducted in high-risk populations. Yet, vulnerability to suicide is likely established years prior to its occurrence. In this study, we aimed to investigate the risk of suicide mortality conferred by prenatal sociodemographic and pregnancy-related factors. Offspring of participants (N = 49,853) of the Collaborative Perinatal Project, a U.S. population-based cohort of pregnancies enrolled between 1959 and 1966, were linked to the U.S. National Death Index to determine their vital status by the end 2016. We examined associations between sociodemographic factors during pregnancy, pregnancy complications, labor and delivery complications, and neonatal complications with suicide death coded according to ICD-9/10 criteria. By the end of 2016, 3,555 participants had died. Of these, 288 (214 males, 74 females) died by suicide (incidence rate = 15.6 per 100,000 person-years, 95% Confidence Interval [CI] = 13.9-17.5). In adjusted models, male sex (Hazard Ratio [HR] = 2.98, CI: 2.26-3.93), White race (HR = 2.14, CI = 1.63-2.83), low parental education (HR = 2.23, CI = 1.38-3.62), manual parental occupation (HR = 1.38, CI = 1.05-1.82), being a younger sibling (HR = 1.52, CI = 1.10-2.11), higher rates of pregnancy complications (HR = 2.36, CI = 1.08-5.16), and smoking during pregnancy (HR = 1,28, CI = 0.99-1.66) were independently associated with suicide risk, whereas birth and neonatal complications were not. Consistent with the developmental origins of psychiatric disorders, vulnerability to suicide mortality is established early in development. Both sociodemographic and pregnancy factors play a role in this risk, which underscores the importance of considering life course approaches to suicide prevention, possibly including provision of high-quality prenatal care, and alleviating the socioeconomic burdens of mothers and families.

A Nation-Wide Swedish Cohort Study on Early Maternal Age at First Childbirth and Risk for Offspring Deaths, Accidents, and Suicide Attempts

In a sample of over one million Swedish first-born offspring, we examined associations between early maternal age at first childbirth (MAFC; i.e., < 20 and 20-24 vs 25-29 years) and offspring non-accidental deaths, accidental deaths, deaths by suicide, non-fatal accidents, and suicide attempts. We included year of birth and several maternal and paternal characteristics as covariates and conducted maternal cousin comparisons to adjust for unmeasured confounding. Early MAFC (e.g., teenage childbearing) was associated with all outcomes, with the most pronounced risk elevation for accidental deaths [Hazard Ratio (HR) < 20 2.50, 95% confidence interval (CI) 2.23, 2.80], suicides (HR < 20 2.08, 95% CI 1.79, 2.41), and suicide attempts (HR < 20 2.85, 95% CI 2.71, 3.00). Adjusting for covariates and comparing cousins greatly attenuated associations (e.g., accidental deaths HR < 20 1.61, 95% CI 1.22, 2.11; suicides HR < 20 1.01, 95% CI 0.69, 1.47; and suicide attempts HR < 20 1.35, 95% CI 1.19, 1.52). A similar pattern emerged for non-accidental deaths and non-fatal accidents. Therefore, results indicated maternal background factors may be largely responsible for observed associations.

Birth order and alcohol-related mortality by ethnic origin and national context: Within-family comparisons for Finland and Sweden

BACKGROUND

Previous studies have found that birth order is an important predictor of later life health, including hospitalisation for alcohol use. We examine the relationship between birth order and alcohol-related mortality in two national contexts, within native families who differ on ethnic origin.

METHODS

We study the association between birth order and alcohol-related mortality after age 17, using Finnish register data for cohorts born 1953-1999 and Swedish register data for cohorts born 1940-1999. We apply Cox proportional hazard models and use sibling fixed effects that eliminate confounding by factors shared by siblings. We separate full-sibling groups by ethnic origin, which for Finland means mother's and father's Finnish or Swedish ethnolinguistic affiliation. For Sweden, we distinguish native-born according to whether one or both parents were born in Sweden or Finland.

RESULTS

We find a positive correlation between birth order and alcohol-related mortality, but only for ethnic Finns in Finland and primarily men. Within these sibling groups, second-borns have an alcohol-related mortality risk that is 9% higher than that of first-borns, third-borns 19 % higher, fourth-borns 22 % higher, and fifth- or higher-borns 47 % higher. No such birth order associations can be found for any of the other ethnic groups analysed in Finland or Sweden.

CONCLUSIONS

Our findings suggest that cultural-related behaviours typical for ethnic groups, and the national context in which they are studied, are relevant for whether any association between birth order and alcohol-related mortality can be observed. Differences in the social interplay within the family may be an important factor.

Suicide among adolescents in Italy: a nationwide cohort study of the role of family characteristics

Suicide is a leading cause of death among adolescents and is recognized as a serious public health problem. This study aimed to investigate the relationship between family characteristics and the risk of suicide among adolescents in Italy using nationwide official data. We carried out a cohort study based on the record linkage between the 15th Italian Population Census, the Italian Population Register, and the National Register of Causes of Death. Suicides in adolescents aged 10-19 years from 2012 to 2016 were analyzed. Hazard ratios of mortality from suicide were estimated through a multivariable Cox regression model using time-on-study as the time scale. We included 8,284,359 children and adolescents (51% males, 49% females). Over the 5-year follow-up, we registered 330 deaths from suicides (74% males), mostly occurred in the age class 15-19 years (86%). The suicide rate was 1.71 per 100,000 person-years among males and 0.65 among females. We found some familial characteristics associated with a higher risk of dying by suicide, including: living in single-parent or reconstructed families (among boys), a 40-year or more age gap between mother and child (among girls), having highly educated parents, an age difference between parents greater than 5 years. Furthermore, the study showed a lower risk for boys living in urban areas and for both boys and girls living in South Italy. Our results could help in identifying adolescents at high risk of suicide who could benefit from the planning of targeted intervention strategies.

Association of Birth Order With Mental Health Problems, Self-Esteem, Resilience, and Happiness Among Children: Results From A-CHILD Study

Objective: This study aimed to investigate the association of birth order with mental health problems, self-esteem, resilience, and happiness among children aged 9-10 years. Methods: This was a cross-sectional study using data from the Adachi Child Health Impact of Living Difficulty (A-CHILD) study, which was a population-based study of children in fourth grade in public schools in Adachi City, Tokyo, Japan in 2018 (N = 3,744). Parent-rated Strengths and Difficulties Questionnaire (SDQ) and self-rated resilience, happiness, and self-esteem score were used to assess child mental health. Multiple regression analysis for continuous outcomes and logistic regression for dichotomous outcomes were used to examine the association of birth order with mental health problems, resilience, happiness, and self-esteem. The analysis was controlled for child sex, mother's age, mother's education, caregiver's depressive symptoms, household income, and living with grandparents. Results: Last-borns showed the lowest total difficulties score in the SDQ, while only children showed the highest (p < 0.001). The highest prosocial behaviors score was found among last-borns (p < 0.001). Resilience score was also highest among last-borns, followed by first-borns, middle-borns, and only children. The lowest happiness score was found among middle-borns. Self-esteem score did not differ by sibling types. These associations were similar in the adjusted model and dichotomized outcomes model. Conclusions: Differential impacts of birth order on child mental health, for both positive and negative sides, were found. Further research is warranted to elucidate the mechanism of the association between birth order and the development of behavior problems and the positive aspects such as resilience, happiness, and self-esteem among children.

Parental age and birth defects: a sibling study

Higher parental age at childbearing has generated much attention as a potential risk factor for birth disorders; however, previous research findings are mixed. Existing studies have exploited variation in parental age across families, which is problematic because families differ not only in parental age but also in genetic and environmental factors. To isolate the effects of parental age, holding many genetic and environmental factors constant, we exploit the variation in parental age within families and compare outcomes for full siblings. The study data were retrieved from the Medical Birth Registry of Norway, which covers the entire population of births in Norway over an extended period (totaling 1.2 million births). Using variation in parental age when siblings were born, we find large and convex effects of increased parental age on the increased risk of birth disorders. To facilitate comparison with the existing literature, we also estimate the effects of parental age using variation in parental age across families and find that the effects are substantially weaker. We conclude that the existing literature may have underestimated the negative effects of parental aging on adverse offspring outcomes.

Prevalence and correlates of non-suicidal self-injury, suicidal ideation, and suicide attempt among children and adolescents: Findings from Uganda and Jamaica

BACKGROUND

Youth non-suicidal self-injury (NSSI) and suicide are major public health concerns, but limited data are available on the prevalence and correlates of these problems in developing countries. The aim of this study is to describe experiences of three suicidal phenomena (NSSI, suicidal ideation [SI], and suicide attempt [SA]) among children and adolescents from two developing countries. We also examine how depression, anxiety, sleep problems, child maltreatment, and other socio-demographic variables associate with the risk of NSSI only, SI only, SA only, and co-occurring NSSI/SI/SA.

METHODS

We conducted a population-based cross-sectional study of school-based Ugandan and Jamaican children and adolescents. Participants were 11,518 (52.4% female) Ugandan and 7,182 (60.8% female) Jamaican youths aged 9-17 years.

RESULTS

The estimated lifetime prevalence of NSSI, SI, and SA was 25.5%, 25.6%, and 12.8% respectively among Ugandan boys and 23.2%, 32.5%, and 15.3% respectively among Ugandan girls. As for the Jamaican sample, the estimated lifetime prevalence of NSSI, SI, and SA was 21%, 27.7%, and 11.9% respectively among boys and 32.6%, 48.6%, and 24.7% respectively among girls. The odds of experiencing SI only, SA only, and co-occurring NSSI/SI/SA were significantly elevated among participants with mild, moderate, and severe depression in both countries.

LIMITATIONS

The current study relied on retrospective data.

CONCLUSIONS

This study found that suicidal phenomena are common among youths from Uganda and Jamaica, with rates substantially higher than among youths from high-income countries. The risk of suicidal phenomena was especially high among youths with severe depression.

Genetic aetiology of self-harm ideation and behaviour

Family studies have identified a heritable component to self-harm that is partially independent from comorbid psychiatric disorders. However, the genetic aetiology of broad sense (non-suicidal and suicidal) self-harm has not been characterised on the molecular level. In addition, controversy exists about the degree to which suicidal and non-suicidal self-harm share a common genetic aetiology. In the present study, we conduct genome-wide association studies (GWAS) on lifetime self-harm ideation and self-harm behaviour (i.e. any lifetime self-harm act regardless of suicidal intent) using data from the UK Biobank (n > 156,000). We also perform genome wide gene-based tests and characterize the SNP heritability and genetic correlations between these traits. Finally, we test whether polygenic risk scores (PRS) for self-harm ideation and self-harm behaviour predict suicide attempt, suicide thoughts and non-suicidal self-harm (NSSH) in an independent target sample of 8,703 Australian adults. Our GWAS results identified one genome-wide significant locus associated with each of the two phenotypes. SNP heritability (hsnp2) estimates were ~10%, and both traits were highly genetically correlated (LDSC rg > 0.8). Gene-based tests identified seven genes associated with self-harm ideation and four with self-harm behaviour. Furthermore, in the target sample, PRS for self-harm ideation were significantly associated with suicide thoughts and NSSH, and PRS for self-harm behaviour predicted suicide thoughts and suicide attempt. Follow up regressions identified a shared genetic aetiology between NSSH and suicide thoughts, and between suicide thoughts and suicide attempt. Evidence for shared genetic aetiology between NSSH and suicide attempt was not statistically significant.

Associations of parental age with offspring all-cause and cause-specific adult mortality

People are having children later in life. The consequences for offspring adult survival have been little studied due to the need for long follow-up linked to parental data and most research has considered offspring survival only in early life. We used Swedish registry data to examine all-cause and cause-specific adult mortality (293,470 deaths among 5,204,433 people, followed up to a maximum of 80 years old) in relation to parental age. For most common causes of death adult survival was improved in the offspring of older parents (HR for all-cause survival was 0.96 (95% CI: 0.96, 0.97) and 0.98 (0.97, 0.98) per five years of maternal and paternal age, respectively). The childhood environment provided by older parents may more than compensate for any physiological disadvantages. Within-family analyses suggested stronger benefits of advanced parental age. This emphasises the importance of secular trends; a parent's later children were born into a wealthier, healthier world. Sibling-comparison analyses can best assess individual family planning choices, but our results suggested a vulnerability to selection bias when there is extensive censoring. We consider the numerous causal and non-causal mechanisms which can link parental age and offspring survival, and the difficulty of separating them with currently available data.

In-utero and perinatal influences on suicide risk: a systematic review and meta-analysis

BACKGROUND

Adverse in-utero and perinatal conditions might contribute to an increased suicide risk throughout the lifespan; however, existing evidence is sparse and contradictory. We aimed to investigate in-utero and perinatal exposures associated with suicide, suicide attempt, and suicidal ideation.

METHODS

We did a systematic review and meta-analysis and searched MEDLINE, Embase, and PsycINFO from inception to Jan 24, 2019, for population-based prospective studies that investigated the association between in-utero and perinatal factors and suicide, suicide attempt, and suicidal ideation. Only papers published in English in peer-reviewed journals were considered. Two researchers independently extracted formal information (eg, country, year, duration of follow-up) and number of cases and non-cases exposed and non-exposed to each risk factor. We calculated pooled odds ratios (ORs) with 95% CIs using random-effects models and used meta-regression to investigate heterogeneity. This study was registered with PROSPERO, number CRD42018091205.

FINDINGS

We identified 42 eligible studies; they had a low risk of bias (median quality score 9/9 [IQR 8-9]). Family or parental characteristics, such as high birth order (eg, for fourth-born or later-born vs first-born, pooled OR 1·51 [95% CIs 1·21-1·88]), teenage mothers (1·80 [1·52-2·14]), single mothers (1·57 [1·31-1·89]); indices of socioeconomic position, such as low maternal (1·36 [1·28-1·46]) and paternal (1·38 [1·27-1·51]) education; and fetal growth (eg, low birthweight 1·30 [1·09-1·55] and small for gestational age 1·18 [1·00-1·40]) were associated with higher suicide risk. Father's age, low gestational age, obstetric characteristics (eg, caesarean section), and condition or exposure during pregnancy (eg, maternal smoking or hypertensive disease) were not associated with higher suicide risk. Similar patterns of associations were observed for suicide attempt and suicidal ideation; however, these results were based on a lower number of studies. In meta-regression, differences in length of follow-up explained most between-study heterogeneity (inital I² ranged from 0 to 79·5).

INTERPRETATION

These findings suggest that prenatal and perinatal characteristics are associated with increased suicide risk during the life course, supporting the developmental origin of health and diseases hypothesis for suicide. The low number of studies for some risk factors, especially for suicide attempt and ideation, leaves gaps in knowledge that need to be addressed. The mechanisms underlying the reported associations and their causal nature still remain unclear.

FUNDING

Horizon 2020 (EU).

Association of birth order with adolescent mental health and suicide attempts: a population-based longitudinal study

Previous cohort studies have observed higher birth order to be associated with increased risk of suicidal behaviour. However, the mechanisms underlying this association are unclear. Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), we used multivariable logistic regression models and mediation analysis to investigate the associations of birth order with adolescent suicide attempts and psychiatric disorder. We investigated whether the number of maternal depressive episodes and father absence mediated the associations found. In fully adjusted models (n = 2571), higher birth order was associated with an increased risk of both suicide attempts (OR = 1.42, CI = 1.10-1.84) and psychiatric disorder (OR = 1.29, CI = 0.99-1.69). Maternal depression and father absence only partially mediated (8%; 12%) these associations. Whilst maternal depression and paternal absence partially mediated the associations between birth order, and suicidal behaviour and psychiatric disorder, other pathways may account for much of these associations. Future studies should investigate alternative mediating pathways.

The androgen model of suicide completion

Suicide is a devastating public health issue that imposes severe psychological, social, and economic burdens not only for the individuals but also for their relatives, friends, clinicians, and the general public. Among the different suicidal behaviors, suicide completion is the worst and the most relevant outcome. The knowledge of biological etiopathological mechanisms involved in suicide completion is limited. Hitherto, no objective markers, either alone or in combination, can reliably predict who will complete a suicide. However, such parameters are strongly needed to establish and optimize prediction and prevention. We introduce here a novel ideation-to-completion framework in suicide research and discuss the problems of studies aiming at identifying and validating clinically useful markers. The male gender is a specific risk factor for suicide, which suggests that androgen effects are implicated in the transition from suicidal ideation to suicide completion. We present multiple lines of direct and indirect evidence showing that both an increased prenatal androgen load (with subsequent permanent neuroadaptations) and increased adult androgen activity are involved in suicide completion. We also review data arguing that modifiable maternal behavioral traits during pregnancy contribute to the offspring's prenatal androgen load and increase the risk for suicide completion later in life. We conclude that in utero androgen exposure and adult androgen levels facilitate suicide completion in an synergistic manner. The androgen model of suicide completion provides the basis for the development of novel predictive and preventive strategies in the future.

Are early-life antecedents of suicide mortality associated with psychiatric disorders and suicidal ideation in midlife?

OBJECTIVE

To establish whether previously identified early-life antecedents of suicide mortality (i.e. low birthweight, younger maternal age, higher birth order, externalizing problems and adversities) are associated with proximal psychiatric disorders and suicidal ideation, which are themselves associated with an increased risk of suicide.

METHODS

Participants were from the 1958 British birth-cohort (N = 8905) with information on prenatal/childhood experiences and the Clinical Interview Schedule-Revised at age 45 years. Outcomes were as follows: any internalizing disorder (anxiety disorder/depressive episode), depressive episode, alcohol use disorder and suicidal ideation.

RESULTS

After adjustment, higher birth order (P_trend = 0.043), younger maternal age (P_trend = 0.017) and increased number of childhood adversities (P_trend = 0.026) were associated with an increased risk of internalizing disorders. For example, the OR (95% CI) in fourth- or later-born children was 1.48 (1.06-2.07) and for young maternal age (<19 years) was 1.31 (0.89-1.91). Effect sizes were similar in magnitude for depressive episode and suicidal ideation, although associations did not reach conventional significance levels. No associations were found for low birthweight and externalizing problems (in males) and investigated outcomes.

CONCLUSION

Associations for younger maternal age, higher birth order and adversities with adult internalizing disorders suggest that psychiatric disorders may be on the pathway linking some early-life factors and suicide.

Suicide in adolescents: findings from the Swiss National cohort

Suicide in adolescents is the second most common cause of death in this age group and an important public health problem. We examined sociodemographic factors associated with suicide in Swiss adolescents and analysed time trends in youth suicide in the Swiss National Cohort (SNC). The SNC is a longitudinal study of the whole Swiss resident population, based on linkage of census and mortality records. We identified suicides in adolescents aged 10-18 years from 1991 to 2013. A total of 2.396 million adolescents were included and 592 suicides were recorded, corresponding to a rate of 3.7 per 100,000 [95% confidence interval (CI) 3.4-4.0]. Rates increased with age from 0.0 per 100,000 at age 10 years to 14.8 per 100,000 (95% CI 12.6-17.5) at 18 years in boys, and from 0.0 to 5.4 per 100,000 (4.1-7.2) in girls. Being a boy, living in a single parent household, being an only or middle-born child, and living in rural regions were factors associated with a higher rate of suicide. Hanging was the most common method in boys, and railway suicides were most frequent in girls. There was no clear evidence for an increase or decrease over calendar time. We conclude that familial and socioeconomic factors including type of household, birth order and urbanity are associated with youth suicide in Switzerland. These factors should be considered when designing prevention programmes for youth suicide.

Influence of exposure to perinatal risk factors and parental mental health related hospital admission on adolescent deliberate self-harm risk

Adolescent deliberate self-harm (DSH) has been found to be associated with a range of bio-psycho-social factors. Simultaneous investigations of these factors enable more robust estimation of the independent effect of a specific risk factor by adjusting for a more complete set of covariates. However, few studies have had the ability to examine all of these factors together. This study used the linkage of population-level de-identified data collections from government agencies to investigate a range of biological, psychological, and social risk factors and their effects on adolescent risk of DSH (with or without suicidal intent). The investigation was undertaken by progressively adjusting for plausible covariates, including fetal growth status and birth order, early familial social factors, parental hospital admissions due to psychiatric disorders or DSH, and parental all-cause death. Conditional logistic regression was used for data analysis. Children's psychiatric history was analysed to examine the extent to which it may account for the link between the risk factors and adolescent DSH risk. This study identified significant biological and perinatal social risk factors for adolescent DSH risk, including overdue birth, high birth order (≥2), single or teen/young motherhood, high neighbourhood socioeconomic disadvantage, and parental psychiatric and/or DSH-related hospital admissions. Further, parental psychiatric and/or DSH-related admissions, and children's psychiatric admissions in particular, largely attenuated the effects of the perinatal social risk factors but not the biological factors on adolescent DSH risk. These results highlight the importance of taking joint actions involving both health and social services in the prevention of adolescent DSH.

Younger or older parental age and risk of suicidality, premature death, psychiatric illness, and criminality in offspring

BACKGROUND

Younger or older parental age has been linked with a range of adverse offspring endpoints. We investigated associations between parental age and nine adverse offspring outcomes in three correlated domains: (i) Premature death: suicide, unnatural death, natural death; (ii) Psychiatric morbidity: any mental illness, suicide attempt, substance misuse; (iii) Criminality: violent offending, imprisonment, driving whilst intoxicated.

METHODS

Persons born in Denmark 1966-1996 were followed from their 15th until 40th birthday or December 2011 (N=1,793,681). Incidence rate ratios were estimated.

RESULTS

Offspring of teenage mothers had the greatest risks for all nine adverse outcomes, especially for imprisonment, violent offending, substance misuse, and attempted suicide. Teenage fatherhood was also associated with elevated risks for offspring adverse psychiatric and criminality outcomes, but not premature mortality (at ages 15-39 years). For the psychiatric and criminality outcomes there was a U-shape trend linked with paternal age, but risks for premature mortality tended to increase with rising paternal age. On the contrary, maternal age 30 years and over was not linked with raised risks for any of the outcomes examined.

LIMITATIONS

Parental links are based on legal and not biological relationships.

CONCLUSIONS

The substantially elevated risks linked with teenage motherhood for a variety of poor offspring outcomes is a concern for clinicians and policymakers. The associations observed across such a wide array of adverse outcomes also suggest that multiple causal mechanisms may be implicated.

Premature Adult Death in Individuals Born Preterm: A Sibling Comparison in a Prospective Nationwide Follow-Up Study

Background

Close to one in ten individuals worldwide is born preterm, and it is important to understand patterns of long-term health and mortality in this group. This study assesses the relationship between gestational age at birth and early adult mortality both in a nationwide population and within sibships. The study adds to existing knowledge by addressing selected causes of death and by assessing the role of genetic and environmental factors shared by siblings.

Methods

Study population was all Norwegian men and women born from 1967 to 1997 followed using nation-wide registry linkage for mortality through 2011 when they were between 15 and 45 years of age. Analyses were performed within maternal sibships to reduce variation in unobserved genetic and environmental factors shared by siblings. Specific outcomes were all-cause mortality and mortality from cardiovascular diseases, cancer and external causes including accidents, suicides and drug abuse/overdoses.

Results

Compared with a sibling born in week 37–41, preterm siblings born before 34 weeks gestation had 50% increased mortality from all causes (adjusted Hazard Ratio (aHR) 1.54, 95% confidence interval (CI) 1.17, 2.03). The corresponding estimate for the entire population was 1.27 (95% CI 1.09, 1.47). The majority of deaths (65%) were from external causes and the corresponding risk estimates for these deaths were 1.52 (95% CI 1.08, 2.14) in the sibships and 1.20 (95% CI 1.01, 1.43) in the population.

Conclusion

Preterm birth before week 34 was associated with increased mortality between 15 and 45 years of age. The results suggest that increased premature adult mortality in this group is related to external causes of death and that the increased risks are unlikely to be explained by factors shared by siblings.

Birth order and hospitalization for alcohol and narcotics use in Sweden

BACKGROUND

Previous studies have shown that birth order is an important predictor of later life health as well as socioeconomic attainment. In this study, we examine the relationship between birth order and hospitalization for alcohol and narcotics use in Sweden.

METHODS

We study the relationship between birth order and hospitalization related to alcohol and narcotics use before and after the age of 20 using Swedish register data for cohorts born 1987-1994. We apply Cox proportional hazard models and use sibling fixed effects, eliminating confounding by factors shared by the siblings.

RESULTS

Before age 20 we find that later born siblings are hospitalized for alcohol use at a higher rate than first-borns, and there is a monotonic increase in the hazard of hospitalization with increasing birth order. Second-borns are hospitalized at a rate 47% higher than first-borns, and third-borns at a rate 65% higher. Similar patterns are observed for hospitalization for narcotics use. After age 20 the pattern is similar, but the association is weaker. These patterns are consistent across various sibling group sizes.

CONCLUSIONS

Later born siblings are more likely to be hospitalized for both alcohol and narcotics use in Sweden. These birth order effects are substantial in size, and larger than the estimated sex differences for the risk of hospitalization related to alcohol and drug use before age 20, and previous estimates for socioeconomic status differences in alcohol and drug abuse.

Child Abuse and Mental Disorders in Iranian Adolescents

Background

Child abuse is a serious social health problem all over the world with important adverse effects.

Objectives

The aim of this study was to extend our understanding of the relation between mental disorders and child abuse.

Materials and Methods

The study was designed as a cross-sectional survey on 700 students in secondary schools using multiple cluster sampling in Yazd, Iran in 2013. We applied 2 self reported questionnaires: DASS (depression anxiety stress scales)-42 for assessing mental disorders (anxiety, stress and depression) and a standard self-reported valid and reliable questionnaire for recording child abuse information in neglect, psychological, physical and sexual domains. The collected data was analyzed using SPSS software. P-values < 0.05 were considered as significant.

Results

There was a statically significant correlation between mental disorder and child abuse score (Spearman rho: 0.2; P-value < 0.001). The highest correlations between mental disorders and child abuse were found in psychological domain, Spearman’s rho coefficients were 0.46, 0.41 and 0.36 for depression, anxiety and stress respectively (P-value < 0.001). Based on the results of logistic regression for mental disorder, females, last born adolescents and subjects with drug or alcohol abuser parents had mental disorder odds of 3, 0.4 and 1.9 times compared to others; and severe psychological abuse, being severely neglected and having sexual abuse had odds 90, 1.6 and 1.5 respectively in another model.

Conclusions

Programming for mandatory reporting of child abuse by physicians and all health care givers e.g. those attending schools or health centers, in order to prevent or reduce its detrimental effects is useful and success in preventing child abuse could lead to reductions in the prevalence of mental disorders.

Birth order and mortality in two ethno-linguistic groups: Register-based evidence from Finland

Previous research has documented an association between birth order and suicide, although no study has examined whether it depends on the cultural context. Our aim was to study the association between birth order and cause-specific mortality in Finland, and whether it varies by ethno-linguistic affiliation. We used data from the Finnish population register, representing a 5% random sample of all Finnish speakers and a 20% random sample of Swedish speakers, who lived in Finland in any year 1987-2011. For each person, there was a link to all children who were alive in 1987. In total, there were 254,059 siblings in 96,387 sibling groups, and 9797 deaths. We used Cox regressions stratified by each siblings group and estimated all-cause and cause-specific mortality risks during the period 1987-2011. In line with previous research from Sweden, deaths from suicide were significantly associated with birth order. As compared to first-born, second-born had a suicide risk of 1.27, third-born of 1.35, and fourth- or higher-born of 1.72, while other causes of death did not display an evident and consistent birth-order pattern. Results for the Finnish-speaking siblings groups were almost identical to those based on both ethno-linguistic groups. In the Swedish-speaking siblings groups, there was no increase in the suicide risk by birth order, but a statistically not significant tendency towards an association with other external causes of death and deaths from cardiovascular diseases. Our findings provided evidence for an association between birth order and suicide among Finnish speakers in Finland, while no such association was found for Swedish speakers, suggesting that the birth order effect might depend on the cultural context.

Late preterm birth, post-term birth, and abnormal fetal growth as risk factors for severe mental disorders from early to late adulthood

BACKGROUND

Late preterm births constitute the majority of preterm births. However, most evidence suggesting that preterm birth predicts the risk of mental disorders comes from studies on earlier preterm births. We examined if late preterm birth predicts the risks of severe mental disorders from early to late adulthood. We also studied whether adulthood mental disorders are associated with post-term birth or with being born small (SGA) or large (LGA) for gestational age, which have been previously associated with psychopathology risk in younger ages.

METHOD

Of 12 597 Helsinki Birth Cohort Study participants, born 1934-1944, 664 were born late preterm, 1221 post-term, 287 SGA, and 301 LGA. The diagnoses of mental disorders were identified from national hospital discharge and cause of death registers from 1969 to 2010. In total, 1660 (13.2%) participants had severe mental disorders.

RESULTS

Individuals born late preterm did not differ from term-born individuals in their risk of any severe mental disorder. However, men born late preterm had a significantly increased risk of suicide. Post-term birth predicted significantly increased risks of any mental disorder in general and particularly of substance use and anxiety disorders. Individuals born SGA had significantly increased risks of any mental and substance use disorders. Women born LGA had an increased risk of psychotic disorders.

CONCLUSIONS

Although men born late preterm had an increased suicide risk, late preterm birth did not exert widespread effects on adult psychopathology. In contrast, the risks of severe mental disorders across adulthood were increased among individuals born SGA and individuals born post-term.

Identifying Chinese Microblog Users With High Suicide Probability Using Internet-Based Profile and Linguistic Features: Classification Model

BACKGROUND

Traditional offline assessment of suicide probability is time consuming and difficult in convincing at-risk individuals to participate. Identifying individuals with high suicide probability through online social media has an advantage in its efficiency and potential to reach out to hidden individuals, yet little research has been focused on this specific field.

OBJECTIVE

The objective of this study was to apply two classification models, Simple Logistic Regression (SLR) and Random Forest (RF), to examine the feasibility and effectiveness of identifying high suicide possibility microblog users in China through profile and linguistic features extracted from Internet-based data.

METHODS

There were nine hundred and nine Chinese microblog users that completed an Internet survey, and those scoring one SD above the mean of the total Suicide Probability Scale (SPS) score, as well as one SD above the mean in each of the four subscale scores in the participant sample were labeled as high-risk individuals, respectively. Profile and linguistic features were fed into two machine learning algorithms (SLR and RF) to train the model that aims to identify high-risk individuals in general suicide probability and in its four dimensions. Models were trained and then tested by 5-fold cross validation; in which both training set and test set were generated under the stratified random sampling rule from the whole sample. There were three classic performance metrics (Precision, Recall, F1 measure) and a specifically defined metric "Screening Efficiency" that were adopted to evaluate model effectiveness.

RESULTS

Classification performance was generally matched between SLR and RF. Given the best performance of the classification models, we were able to retrieve over 70% of the labeled high-risk individuals in overall suicide probability as well as in the four dimensions. Screening Efficiency of most models varied from 1/4 to 1/2. Precision of the models was generally below 30%.

CONCLUSIONS

Individuals in China with high suicide probability are recognizable by profile and text-based information from microblogs. Although there is still much space to improve the performance of classification models in the future, this study may shed light on preliminary screening of risky individuals via machine learning algorithms, which can work side-by-side with expert scrutiny to increase efficiency in large-scale-surveillance of suicide probability from online social media.

Maternal Grand Multiparity and the Risk of Severe Mental Disorders in Adult Offspring

BACKGROUND

Previous studies have shown that maternal grand multiparity may predict an increased risk of mental disorders in young adult offspring, but whether such effects persist throughout adulthood remains unknown. The current study examined if maternal grand multiparity predicts the risks of severe mental disorders, suicides, suicide attempts and dementias throughout adult life.

METHODS

Our study sample comprised 13243 Helsinki Birth Cohort Study 1934-1944 participants (6905 men and 6338 women). According to hospital birth records, 341 offspring were born to grand multiparous mothers. From Finnish national hospital discharge and causes of death registers, we identified 1682 participants diagnosed with mental disorders during 1969-2010.

RESULTS

Maternal grand multiparity predicted significantly increased risks of mood disorders (Hazard Ratio = 1.64, p = 0.03), non-psychotic mood disorders (Hazard Ratio = 2.02, p = 0.002), and suicide attempts (Hazard Ratio = 3.94, p = 0.01) in adult offspring. Furthermore, women born to grand multiparous mothers had significantly increased risks of any severe mental disorder (Hazard Ratio = 1.79, p = 0.01), non-psychotic substance use disorders (Hazard Ratio = 2.77, p = 0.02) schizophrenia, schizotypal and delusional disorders (Hazard Ratio = 2.40, p = 0.02), mood disorders (Hazard Ratio = 2.40, p = 0.002), non-psychotic mood disorders (Hazard Ratio = 2.91, p<0.001), and suicide attempts (Hazard Ratio = 5.05, p = 0.01) in adulthood. The effects of maternal grand multiparity on offspring psychopathology risk were independent of maternal age and body mass index at childbirth, and of year of birth, sex, childhood socioeconomic position, and birth weight of the offspring. In contrast, no significant effects were found among men.

CONCLUSIONS

Women born to grand multiparous mothers are at an increased risk of severe mental disorders and suicide attempts across adulthood. Our findings may inform the development of preventive interventions for mental disorders.

Birth order and physical fitness in early adulthood: evidence from Swedish military conscription data

Physical fitness at young adult ages is an important determinant of physical health, cognitive ability, and mortality. However, few studies have addressed the relationship between early life conditions and physical fitness in adulthood. An important potential factor influencing physical fitness is birth order, which prior studies associate with several early- and later-life outcomes such as height and mortality. This is the first study to analyse the association between birth order and physical fitness in late adolescence. We use military conscription data on 218,873 Swedish males born between 1965 and 1977. Physical fitness is measured by a test of maximal working capacity, a measure of cardiovascular fitness closely related to V02max. We use linear regression with sibling fixed effects, meaning a within-family comparison, to eliminate the confounding influence of unobserved factors that vary between siblings. To understand the mechanism we further analyse whether the association between birth order and physical fitness varies by sibship size, parental socioeconomic status, birth cohort or length of the birth interval. We find a strong, negative and monotonic relationship between birth order and physical fitness. For example, third-born children have a maximal working capacity approximately 0.1 (p < 0.000) standard deviations lower than first-born children. The association exists both in small (3 or less children) and large families (4 or more children), in high and low socioeconomic status families, and amongst cohorts born in the 1960s and the 1970s. While in the whole population the birth order effect does not depend on the length of the birth intervals, in two-child families a longer birth interval strengthens the advantage of the first-born. Our results illustrate the importance of birth order for physical fitness, and suggest that the first-born advantage already arises in late adolescence.

Birth order and suicide in adulthood: evidence from Swedish population data

Each year, almost 1 million people die from suicide, which is among the leading causes of death in young people. We studied how birth order was associated with suicide and other main causes of death. A follow-up study based on the Swedish population register was conducted for sibling groups born from 1932 to 1980 who were observed during the period 1981-2002. Focus was on the within-family variation in suicide risk, meaning that we studied sibling groups that consisted of 2 or more children in which at least 1 died from suicide. These family-fixed effects analyses revealed that each increase in birth order was related to an 18% higher suicide risk (95% confidence interval (CI): 1.14, 1.23, P = 0.000). The association was slightly lower among sibling groups born in 1932-1955 (hazard ratio = 1.13, 95% CI: 1.06, 1.21, P = 0.000) than among those born in 1967-1980 (hazard ratio = 1.24, 95% CI: 0.97, 1.57, P = 0.080). Further analyses suggested that the association between birth order and suicide was only modestly influenced by sex, birth spacing, size of the sibling group, own socioeconomic position, own marital status, and socioeconomic rank within the sibling group. Causes of death other than suicide and other external causes were not associated with birth order.

Invited commentary: birth order and suicide in a broader context

In this issue of the Journal, Bjørngaard et al. give us new insights into the etiology of mental health by studying birth order and suicide risk (Am J Epidemiol. 2013;177(7):638-644). Although the authors provided empirical evidence that each increase in birth order (i.e., from first-born to second-born, second-born to third-born, etc.) is associated with a 46% higher suicide risk, they gave us very little information on the likely explanations. In our commentary, we draw attention to the possible mechanisms underlying a causal relationship between birth order and suicide. Given that Norway is one of the richest countries in the world, the findings of Bjørngaard et al. in a Norwegian cohort also call for a discussion of whether their results are representative of other societies that are similar or dissimilar with respect to economic institutions, social conditions, and political environment. We suggest that there are several plausible mechanisms to explain higher suicide rates among later-born children, but other mechanisms might also operate in the opposite direction, that is, have beneficial outcomes among later-born children. Specifically, there are reasons to expect a different relationship between birth order and psychiatric outcomes in poorer societal contexts.