Sibling Groups Research Articles

Lower percentages of natural killer cells in children with type 1 diabetes and their siblings.

One of the most common children's endocrine and autoimmune diseases in the world is type 1 diabetes mellitus (T1DM). The incidence of type 1 diabetes is constantly increasing, and according to current estimates, the number of children with T1DM in the world has exceeded 542,000. There are 3 main components emphasized in the pathogenesis: genetic and environmental factors, and the patient's immune system. Many publications have confirmed the role of natural killer cells (NK) in the pathogenesis of type 1 diabetes and other autoimmune diseases. The aim of the study was to evaluate the population of NK cells and pancreatic β cell autoantibodies in a group of children with T1DM and their healthy siblings in comparison with children from families with no history of autoimmune diseases. The research included 76 children with T1DM, 101 children from the sibling group, and 30 children from the control group. Peripheral blood was analysed on a FACSCalibur flow cytometer (Becton Dickinson) to evaluate the NK cell population. The results were presented as the percentage of NK cells among lymphocytes. Statistical analysis was performed using STATIS-TICA 10 PL software. The mean percentage of NK cells in children with T1D (10.59 ±5.37) and in the sibling group (11.93 ±5.62) was statistically reduced in comparison to the control group (14.89 ±7.78) in sequence (Student's t -test: t = -3.24; df = 103; p = 0.002) (Stu-dent's t -test: t = -2.30; df = 128; p = 0.02). There was no statistically significant difference in the percentage of NK cells be-tween the group of children with T1DM and their siblings (Student's t -test: t = -1.59; df = 173; p = 0.11). In the group of sib-lings, the younger the child, the lower the reported percentage of NK cells. This relationship was statistically significant (test for the Pearson correlation coefficient t = 3.41; p = 0.0009; r = 0.33). In the group of children with type 1 diabetes, a similar relationship was not found. The concentration of anti-IA2 and anti-Znt8 antibodies was statistically significantly higher in the sibling group compared to the control group (anti-IA2 p = 0.0000001; anti-ZnT8 p = 0.00001), and the concentration of anti-GAD antibodies was comparable in both groups. In the group of children with type 1 diabetes, a positive correlation was demonstrated between the reduced percentage of NK cells and the coexistence of anti-GAD and anti-ZnT8 antibodies (Mann-Whitney U test Z = -2.02; p = 0.04). There was no similar relationship in the group of siblings. The reduced percentage of NK cells in children with T1DM and in their siblings compared to the control group suggests the role of NK cells in the pathogenesis of T1DM. Genetic predisposition and dysfunction of NK cells probably underlie the pathogenesis of T1DM.

Mother’s warmth from maternal genes: genomic imprinting of brown adipose tissue

Abstract Background and objectives Brown adipose tissue (BAT) plays key roles in mammalian physiology, most notably with regard to thermoregulation in infants and juveniles. Previous studies have suggested that intragenomic conflict, in the form of genomic imprinting, mediates BAT thermogenesis, because it represents a public good for groups of siblings, or a mother with her offspring, who huddle together to conserve warmth. By this hypothesis, maternally expressed imprinted genes should promote BAT, while paternally expressed genes should repress it. Methodology We systematically searched the literature using two curated lists of genes imprinted in humans and/or mice, in association with evidence regarding effects of perturbation to imprinted gene expression on BAT development or activity. Results Overall, enhanced BAT was associated with relatively higher expression of maternally expressed imprinted genes, and relatively lower expression of paternally expressed imprinted genes; this pattern was found for 16 of the 19 genes with sufficient information for robust ascertainment (Binomial test, P < 0.005, 2-tailed). Conclusions and implications These results support the kinship theory of imprinting and indicate that future studies of BAT, and its roles in human health and disease, may usefully focus on effects of imprinted genes and associated genomic conflicts.

Childhood trauma and neurocognitive functions in individuals with bipolar disorder and unaffected siblings of individuals with bipolar disorder

Previous studies have suggested a possible connection between childhood trauma, the course of illness, and neurocognitive impairment in individuals with bipolar disorder (BD). This cross-sectional study aimed to investigate the relationship between childhood trauma and neurocognitive functioning in a sample consisting of 41 euthymic individuals with BD, 37 individuals who have at least one sibling with BD, and 48 healthy controls (HCs). We assessed childhood trauma history using the Childhood Trauma Questionnaire (CTQ). Both the BD and Sibling groups showed higher rates of emotional abuse, neglect, and higher total trauma scores compared to the HCs. A principal component analysis of the neurocognitive test battery revealed a global cognition factor responsible for 49.40% of the variance and five subsequent neurocognitive components: working memory & response inhibition, verbal memory, visual copying, verbal fluency, and processing speed. Individuals with BD had lower scores in verbal memory, visual copying, processing speed, and global cognitive factor domains than the Siblings and HCs. The Siblings' performance was similar to that of the HC group. Correlation analyses showed significant correlations between physical neglect, sexual abuse, and neurocognitive domains like processing speed, verbal fluency, working memory, and the global cognitive factor. However, the linear regression analyses didn’t reveal a significant influence of childhood trauma on neurocognitive domains. Our findings indicate that both individuals with BD and their unaffected siblings have a high occurrence of childhood trauma, but presence of bipolar disorder itself appears to influence neurocognitive functioning independently of childhood traumatic experiences or familial predisposition to bipolar disorder.

Functional and Taxonomic Traits of the Gut Microbiota in Type 1 Diabetes Children at the Onset: A Metaproteomic Study.

Type 1 diabetes (T1D) is a chronic autoimmune metabolic disorder with onset in pediatric/adolescent age, characterized by insufficient insulin production, due to a progressive destruction of pancreatic β-cells. Evidence on the correlation between the human gut microbiota (GM) composition and T1D insurgence has been recently reported. In particular, 16S rRNA-based metagenomics has been intensively employed in the last decade in a number of investigations focused on GM representation in relation to a pre-disease state or to a response to clinical treatments. On the other hand, few works have been published using alternative functional omics, which is more suitable to provide a different interpretation of such a relationship. In this work, we pursued a comprehensive metaproteomic investigation on T1D children compared with a group of siblings (SIBL) and a reference control group (CTRL) composed of aged matched healthy subjects, with the aim of finding features in the T1D patients' GM to be related with the onset of the disease. Modulated metaproteins were found either by comparing T1D with CTRL and SIBL or by stratifying T1D by insulin need (IN), as a proxy of β-cells damage, showing some functional and taxonomic traits of the GM, possibly related to the disease onset at different stages of severity.

Educational pathways of childhood cancer survivors—a parental cohort

PurposeUsing the International Standard Classification of Education (ISCED), we examined the educational and vocational pathways of two comparable, parental cohorts: childhood cancer survivors (CCS) and their siblings. Both cohorts had previously entered parenthood. The aim of the study was to elucidate whether childhood cancer and treatment affect the educational pathways chosen by parents who are former patients.MethodsWe analysed data that was collected from childhood cancer survivors and their siblings regarding their offspring’s health within the FeCt Multicentre Offspring Study (conducted 2013–2016). We evaluated and compared the professional pathways of (i) all participating survivors and all participating siblings and those of (ii) survivors and their biological siblings.ResultsOverall information on parental gender, age, and education were available from 1077 survivors and 246 siblings (group (i)). The majority of participants were female with a mean age of 35.2 (survivor) and 37.9 (sibling) years at time of survey. For subgroup (ii), analysis information was available on 191 survivors and 210 siblings. Fathers achieved university degrees significantly more often than mothers (p = 0.003 (i), p < 0.001 (ii)). The distribution of professional education was not significantly different between cancer survivors and siblings in either cohort (i) or (ii).ConclusionsRegarding our research on the educational and vocational trajectory of CCS, patients can be reassured that family planning and vocational education are well compatible. Inequalities regarding gender-specific educational pathways remain to be addressed.Implications for Cancer SurvivorsCCS should monitor their fertility status regularly and, if necessary, cryopreserve germ cells or tissue in order to optimize their family planning. Educational opportunities should be pursued as desired and with confidence. Local as well as European aftercare programs can assist with family planning and education.

Longitudinal Relations Between Early Sensory Responsiveness and Later Communication in Infants with Autistic and Non-autistic Siblings.

Early differences in sensory responsiveness may contribute to difficulties with communication among autistic children; however, this theory has not been longitudinally assessed in infants at increased familial versus general population-level likelihood for autism (Sibs-autism vs. Sibs-NA) using a comprehensive battery of sensory responsiveness and communication. In a sample of 40 infants (20 Sibs-autism, of whom six were later diagnosed with autism; 20 Sibs-NA), we tested (a) associations between sensory responsiveness at 12-18months and communication 9months later and (b) evaluated whether such associations were moderated by sibling group, autism diagnosis, or age. We found negative zero-order correlations between sensory responsiveness (i.e., caregiver reported hyperresponsiveness and hyporesponsiveness; an observational measure of hyperresponsiveness) and later communication. Additionally, caregiver reported sensory seeking was negatively associated with later expressive communication only in Sibs-NA. Limitations include our relatively small sample size of infants diagnosed with autism. Implications for future research are discussed.

An observational investigation of the faecal microbiota and metabonome of gastrostomy fed children, on blended and formula diets

ABSTRACT Gastrostomy fed children traditionally have a Formulae diet (FD), which fulfills nutritional requirements; however, many families are adopting Blended diets (BD), which are what the whole family would eat. We undertook an observational investigation of the colonic microbiota and metabonome in a small group of gastrostomy fed children, who were either on an FD or BD, and compared, where possible to their siblings (17 FD, 28 BD, 19 HS). There was no increase in complications in tube blockage or infection rates, but a significant improvement in the prevalence of bowel problems, a reduction in medication and an increase in quality of life. Metataxonomic analysis showed that the FD group was significantly different to the Sibling group, and that families did not cluster together. Whole sample metabonomics showed no differences between groups; however, univariate analysis of biologically important metabolites did differ. Changing to a BD resulted in no increase in complications or risks, but improved the overall quality of life for the children and families.

Young Bereaved Siblings of Security Personnel in Israel: The Role of Parents and Professional Helpers in Satisfying Their Needs.

This paper addresses bereavement of young siblings of security personnel in Israel. It focuses on their needs and their satisfaction. It examines interactions between the siblings, their parents, and professional helpers in this respect. This paper is based on a qualitative study utilizing focus groups of adult bereaved siblings, bereaved parents, and professional helpers. The cross-referencing analysis of the findings revealed distinct patterns of behavior, family dynamics, and interactions with professional helpers, often causing the needs of young bereaved siblings to remain unmet. Professional intervention with young bereaved siblings is recommended through all stages of bereavement, in order to better meet their needs.

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

Abstract Background In working ages, sickness absence is strongly related to persons’ health condition. We studied how birth order was associated with receipt of sickness absence, distinguishing 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. Stratified Cox regressions were estimated using Stata 16. Results Each increase in birth order was associated with a higher risk of sickness absence. For mental disorders, the hazard ratio as compared to first borns was 1.03 (95% CI: 0.98, 1.08) of second borns, 1.10 (95% CI: 0.99, 1.22) of third borns, and 1.52 (95% CI: 1.25, 1.85) of fourth or higher borns. Corresponding numbers for musculoskeletal disorders were 1.12 (95% CI: 1.07, 1.17), 1.19 (95% CI: 1.09, 1.30) and 1.15 (95% CI: 0.96, 1.38), and for injuries 1.06 (95% CI: 1.01, 1.12), 1.09 (95% CI: 1.21, 1.14) and 0.96 (95% CI: 0.77, 1.20), respectively. These associations were notably stronger for women than men, but modestly influenced by mother’s age at birth, educational level, occupation, income and family composition. Conclusions The study was the first to provide evidence about an interrelation between birth order and sickness absence, utilising diagnose information and family fixed effects methods. A clear birth order pattern was observed for these main causes, but not for a residual group that consisted of other miscellaneous causes. Higher birth order was found associated with a higher risk of sickness absence, and particularly so for mental disorders and muscoloskeletal disorders in women. The underlying mechanisms behind these associations constitute an avenue for future research. Key messages • Using sibling fixed effects, the study was the first to analyse if sickness absence by main cause is associated with birth order in working ages. • First-born siblings were the least likely to be sick because of mental or musculoskeletal disorders, and the associations were notably more accentuated for women than men.

Inbreeding affects juvenile shoaling behaviour in sibling groups of a cichlid fish

Whilst the effects of inbreeding on growth and survival have been well studied, knowledge on the impact of inbreeding on the social behaviour is scarce. Animal groups are often composed of relatives, which can facilitate cooperation (due to kin selection) and improve group performance accordingly. Therefore, increased genetic relatedness in inbred kin groups could increase group performance, whilst the reduced genetic diversity could have negative effects (inbreeding depression). We compared the juvenile shoaling behaviour of inbred and outbred sibling groups in Pelvicachromis taeniatus (Boulenger 1901), a West-African cichlid fish with kin mating preferences. Activity (travelled distance), shoal density (inter-individual distance) and recovery from a disturbance (freezing time) in a novel environment were analysed using tracking software. Inbred individuals travelled shorter distances compared to outbred individuals, which may decrease conspicuousness and thus predation risk. Furthermore, inbred sibling groups recovered faster after the disturbance compared to outbred sibling groups suggesting improved coordination. In conclusion, our study revealed differences in shoaling between inbred and outbred sibling groups. The higher relatedness in inbred groups may have positive effects in the form of a reduced conspicuousness. The reduced activity may impair foraging success under natural conditions which might, however, be compensated by faster recovery from disturbances.

The Role of Internal and External Factors for Code-Switching: A Study of Early Multilingualism in Germany with Special Reference to Catalan as a Heritage Language

In heritage language acquisition studies, it has been observed that heritage speakers may experience a shift of language dominance from the heritage language to the majority language due to input quantity and quality factors. The appearance of code-switching in the productions of multilingual speakers has been well attested and has been mostly linked to age and language dominance as well as family language policies and consistence of input, among other factors. For the appearance of code-switching, our cross-sectional study analyses language dominance (MLU) and fluency (w/minute) along with child-external factors, such as family language policies, family language and siblings’ interaction, in sixteen multilingual children (mean age 5;7) being raised in Germany with German and Catalan (and another L1) simultaneously. In a nutshell, children who are dominant in the majority language ultimately code-switch more frequently than the other groups. Interestingly, balanced and heritage-language-dominant children present instances of intrasentential code-switching (particularly insertions and alternations), while intersentential code-switching is frequent across all groups. When families have chosen the ‘one person-one language’ strategy and do not have a family language, code-switching is almost absent. Finally, sibling groups using both the heritage and the majority languages in their interactions show low code-switching rates.

Lifestyle risk factors and metabolic markers of cardiovascular diseases in Bangladeshi rural-to-urban male migrants compared with their non-migrant siblings: A sibling-pair comparative study.

The increasing prevalence of cardiovascular diseases (CVDs) in developing countries like Bangladesh has been linked to progressive urbanisation. Comparisons of rural and urban populations often find a higher prevalence of CVD risk factors in the urban population, but rural-to-urban migrants might have different CVD risk profiles than either rural or urban residents. This study aimed to describe differences in CVD risk factors between migrants and non-migrants siblings and to determine whether acculturation factors were associated with CVD risk factors among migrants. Using a sibling-pair comparative study, 164 male migrant who migrated from Pirganj rural areas to Dhaka City and their rural siblings (total N = 328) were assessed by interview, anthropometric measurement, blood pressure and blood samples. Comparisons were made using linear or logistic mixed effects models. Physical inactivity, inadequate intake of fruit and vegetables and possible existence of a mental health disorder had 3.3 (1.73; 6.16), 4.3 (2.32; 7.92) and 2.9 (1.37; 6.27) times higher odds among migrants than their rural siblings, respectively. Migrants watched television on average 20 minutes (95% CI 6.17-35.08 min/day) more per day than the rural sibling group whereas PUFA intake, fruit and vegetable and fish intake of the migrants were -5.3 gm/day (-6.91; -3.70), -21.6 serving/week (-28.20; -15.09), -14.1 serving/week (-18.32; -9.87), respectively, lower than that of the rural siblings. No significant difference was observed for other variables. After adjusting, the risk of physical inactivity, inadequate fruit and vegetable intake, a mental health disorder and low HDL were significantly higher in migrants than in rural siblings and tended to be higher for each increasing tertile of urban life exposure. The findings suggest that migration from rural-to-urban environment increases CVD risk which exacerbate with time spent in urban area due to acculturation. This study gives new insights into the increased CVD risk related with migration and urbanization in Bangladesh.

Sibling group size and BMI over the life course: Evidence from four British cohort studies.

Only children, here defined as individuals growing up without siblings, are a small but growing demographic subgroup. Existing research has consistently shown that, on average, only children have higher body mass index (BMI) than individuals who grow up with siblings. How this difference develops with age is unclear and existing evidence is inconclusive regarding the underlying mechanisms. We investigate BMI trajectories for only children and those with siblings up to late adolescence for four British birth cohorts and across adulthood for three cohorts. We use data on BMI from ages 2-63 years (cohort born 1946); 7-55 years (born 1958); 10-46 (born 1970) and 3-17 years (born 2000-2002). Using mixed effects regression separately for each cohort, we estimate the change in BMI by age comparing only children and those with siblings. The results show higher average BMI among only children in each cohort, yet the difference is substantively small and limited to school age and adolescence. The association between sibling status and BMI at age 10/11 is not explained by differential health behaviours (physical activity, inactivity and diet) or individual or family background characteristics in any of the cohorts. Although persistent across cohorts, and despite the underlying mechanism remaining unexplained, the substantively small magnitude of the observed difference and the convergence of the trajectories by early adulthood in all cohorts raises doubts about whether the difference in BMI between only children and siblings in the UK context should be of research or clinical concern. Future research could usefully be directed more at whether only children experience elevated rates of disease, for which high BMI is a risk factor, at different stages of the life course and across contexts.

The family stress model and parents' differential treatment of siblings: A multilevel meta-analysis.

The family stress model (FSM) suggests that stress, particularly economic stress, hinders effective parenting. Expanding on the FSM, the present study examined not only the economic stress but also the general stress and several contexts that may promote stress-namely, physical health, mental health, socioeconomic status, employment status, and marital status. The present study also expanded the FSM to examine parenting of sibling groups. Ineffective parenting of sibling groups was conceptualized as greater parental differential treatment (PDT). A number of moderating variables were also considered. Multilevel meta-analysis models were used to test hypotheses. Across models, data came from 6,003 effect sizes, nested within 59 sources, nested within 16 unique samples (all coming from 8 published studies and 11 raw data sets). Results showed main effects for only parents' general stress and parents' mental health. More stress and poorer mental health were linked with greater amounts of PDT. Additionally, poorer physical health was linked to greater PDT but only when PDT involved positive parent-child interactions. As a whole, findings suggested that actual feelings of stress and psychological distress may show stronger links with PDT than contexts that merely have the potential to cause stress. Caution is warranted, however, as effect sizes were generally small and some models were based on predominantly Caucasian samples. Future research on the FSM and PDT should focus on actual experiences of stress and further consider the moderating role of domains of parenting. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Birth order and pediatric traumatic brain injury

Pediatric traumatic brain injury (TBI) is a significant problem of public health importance worldwide. Large population-based studies on the effect of birth order on health phenomena are exceedingly rare. This study examines the relationship between birth order and risk for pediatric TBI among sibling groups. We performed a retrospective cohort study following 59,469 Finnish newborns from 1987 until age 18 years. Data on first diagnosis of TBI was recorded within the 1987 Finnish Birth Cohort (FBC). Compared with first born siblings, later born siblings had an increased risk of TBI during the follow-up period (hazard ratio [HR] 1.02; 95% confidence interval [CI] 0.91–1.14 for second born, HR 1.09; 95% CI 0.95 1.26 for third born, HR 1.28; 95% CI 1.08–1.53 for fourth or higher). When adjusted for sex and maternal age at child’s birth, HRs (95% CIs) for TBI during the follow-up period were 1.12 (0.99–1.26) for second born, 1.31 (1.12–1.53) for third born and 1.61 (1.33–1.95) for fourth born or higher children, respectively. Within this large register-based population-wide study, order of birth modified risk for pediatric TBI among sibling groups. Taken together, these study findings may serve to stimulate further inquiry into genetic, psychological, or psychosocial factors which underlie differences in risk and depth of effect within and between sibling groups.

Arguments among siblings: Format tying as a resource in conflict talk and conflict resolution

Sibling interaction is a key socializing arena for language practices due to the variety of age and position of the siblings; the ever-looming possibility of conflict also equip children with abilities for conflict management and resolution. Using Conversation Analysis, this study examines data from videorecordings of a family including two parents and four children under the age of twelve during mealtimes and play. The analysis focuses on format tying, i.e. a way to produce new turns-at-talk by incorporating parts of a previous turn, within conflict talk among the siblings. We illustrate two functions of format tying: the first is in lending structure to argumentative moves, where format tying reveals affordances for escalating conflict. The second is the transformation of an initial conflict into verbal play, with the repetition triggering language reflexivity. Finally, we discuss format tying as a readily available resource for engagement within the siblings group, and its contribution to family politics.

Frequency of Fetal Hemoglobin Level in Siblings of Betathalassemia Major patients

Aim: To see the frequency of fetal haemoglobin level in siblings of beta thalassemia major (BTM) patients. Study population: A total of 400 subjects were included. Grouping: Group A includes normal siblings of BTM cases, B includes beta thalassemia trait (BTT) siblings of BTM cases and group C were healthy controls. Selection criteria: Asymptomatic siblings of diagnosed cases of beta thalassemia major were included. Patients with history or diagnosis of any acute or chronic illnesses were excluded from the study. 5 ml of blood was taken in EDTA vial and used for haemoglobin electrophoresis. Results: In 200 cases, 78% (156) were beta thalassemia trait (BTT) siblings and fetal Hb was also more in BTT siblings i.e. Group B. Conclusion: Fetal haemoglobin (HbF) was increased in BTT siblings (group B) of BTM cases. Keywords: Hb electrophoresis, fetal Hb, beta thalassemia major

Cortical thickness and surface area in patients with obsessive compulsive disorder and their unaffected siblings.

Little is known about the underlying neurobiological mechanisms in patients with obsessive-compulsive disorder (OCD). We aimed to examine cortical thickness and surface area in individuals with OCD and their unaffected siblings, comparing them to healthy controls. 30 patients with OCD, 21 unaffected siblings (SIB) and 30 controls underwent structural magnetic resonance imaging. Structural images were analyzed using the FreeSurfer software package (version 6.0). Compared to healthy controls, both OCD and SIB groups showed significantly lower cortical thickness in the right anterior insula. Surface areas of the superior frontal gyrus, paracentral gyrus and precuneus of the right hemisphere were also reduced in OCD patients compared to controls. There were no significant differences in cortical thickness and surface area between the OCD and SIB groups. We did not detect any significant differences in subcortical volumes between groups. Lower cortical thickness in the right anterior insula in both OCD patients and unaffected siblings may represent a potential structural endophenotype for OCD.

Vaccination Behavior Among Children With Developmental Delay and Their Siblings: A Cross-Sectional Study From India.

Objective: Despite scientific evidence to the contrary, parental concerns with respect to the association between vaccination and development of autism spectrum disorder persist. The objective of this study was to assess the vaccination uptake and its associated factors in siblings of children with developmental delay.Methods: This cross-sectional study was conducted from December 2017 to February 2018. The families of children with developmental delay, according to evaluation by a psychiatrist per ICD-10 criteria, were recruited from 3 child development centers. The data were collected using a semistructured questionnaire.Results: 189 families with children with developmental delay were recruited into the study. In total, these children had 114 typically developing elder siblings and 50 typically developing younger siblings. The proportions of overall complete vaccination among the children with developmental delay group and the younger sibling group were significantly lower than the older sibling group (P < .01). The proportions of MMR (mumps, measles, and rubella) vaccination among the children with developmental delay group and the younger sibling group were significantly lower than the older sibling group (P < .001).Conclusions: Findings from this study suggest that reduced vaccination uptake is a general trend in families of children with developmental delay. Such a significant decline in the vaccination rate in this group of children will make them vulnerable if outbreaks occur. Therefore, public health strategies targeted to improve vaccination rates in families of children with developmental delay are needed.

The effect of birth order on length of hospitalization for pediatric traumatic brain injury: an analysis of the 1987 Finnish birth cohort

PurposeThis study examines the relationship between birth order and length of hospitalization due to pediatric traumatic brain injury (TBI).MethodsWe prospectively followed 59,469 Finnish newborns from 1987 until age 18 years. Data on first diagnosis of TBI was recorded within the 1987 Finnish Birth Cohort (FBC). Hospitalization period was divided into two categories: 2 days or less and more than 2 days. The latter was considered in this study as longer hospitalization.ResultsCompared with first born siblings, later born siblings had an increased risk of a longer hospitalization for TBI (12.7% of fourth or higher born birth children diagnosed with TBI were hospitalized for 2 or more days, 11.3% of first born, 10.4% of third born and 9.0% of second born). Fourth or higher born children were more likely to experience a repeat TBI; 13.4% of fourth or higher born children diagnosed with TBI had 2–3 TBIs during the study period compared to 9% of third born, 7.8% of second born and 8.8% of the first born. Injuries in the traffic environment and falls were the most common contributors to pediatric TBI and occurred most frequently in the fourth or higher birth category; 29.3% of TBIs among fourth or higher birth order were due to transport accidents and 21% were due to falls.ConclusionsThis study revealed a significant increase in risk for longer hospitalization due to TBI among later born children within the same sibling group. The study provides epidemiological evidence on birth order as it relates to TBI, and its potential to help to explain some of the statistical variability in pediatric TBI hospitalization over time in this population.