Is the Risk of Autism in Younger Siblings of Affected Children Moderated by Sex, Race/Ethnicity, or Gestational Age?

Familial Recurrence of Autism: Updates From the Baby Siblings Research Consortium

OBJECTIVES

Autism spectrum disorder (ASD) is estimated to be ∼10 times higher in children with versus without an autistic sibling in population-based studies. Prospective studies of infant siblings have revealed even higher familial recurrence rates. In the current prospective longitudinal study, we provide updated estimates of familial ASD recurrence using a multinational database of infants with older autistic siblings.

METHODS

Data were collated across 18 sites of the Baby Siblings Research Consortium, an international network studying the earliest manifestations of ASD. A total of 1605 infants with an older autistic sibling were followed from early in life to 3 years, when they were classified as ASD or non-ASD. Hierarchical generalized linear modeling, with site as a random effect, was used to examine predictors of recurrence in families and calculate likelihood ratios.

RESULTS

A total of 20.2% of siblings developed ASD, which is not significantly higher than the previously reported rate of 18.7%. Male infant sex and >1 older affected sibling were significant predictors of familial recurrence. Proband sex also influenced recurrence rates, with siblings of female probands significantly more likely to develop ASD than siblings of male probands. Race and maternal education were also associated with recurrence in families.

CONCLUSIONS

The familial recurrence rate of ASD, as measured in infant sibling studies, has not changed appreciably since previous estimates were made in 2011. Younger siblings of autistic children, particularly those who are male, have an affected female sibling, multiple affected siblings, or are impacted by social inequities, should be closely monitored and promptly referred for diagnostic evaluation.

Knowledge and Attitudes toward Autism Spectrum Disorder in Saudi Arabia

Aims: The diagnosis of autism spectrum disorder (ASD) is not easy as there is no direct test that exists to establish such a diagnosis. Increasing community and healthcare professional knowledge of the ASD spectrum is crucial because it will encourage parents of ASD children to seek screening and diagnosis from a specialist, allowing for better early detection and treatment. This study explored the knowledge of the general population in Saudi Arabia regarding ASD and assessed variables associated with an accurate understanding of ASD. Methods: A total of 769 participants were involved in this cross-sectional study, which was conducted in Saudi Arabia between November 2021 and February 2022 using an online survey tool to explore the knowledge of the general population in Saudi Arabia regarding typical child development and ASD. A binary logistic regression analysis was used to determine factors affecting participants’ knowledge of autism. Results: Overall, the study participants showed a weak level of knowledge about autism with a mean score of 5.9 (SD: 3.1), comprising 34.7% of the total maximum obtainable score. Participants with a middle income category of 5000–7500 SR are less likely to be knowledgeable about autism compared to others (OR: 0.60 (95% CI: 0.39–0.92)) (p-value = 0.020). Conclusion: The participants in our study showed limited knowledge about autism. Government funds should be made available to facilitate educational services for ASD children. More funding and resources should be allocated by the government to provide assistance for children with special needs, and changes in public facilities are required to meet the demands of ASD patients. Through an informed educational effort, various media platforms should assist in improving the community’s understanding of ASD and their attitude toward ASD patients. Educational campaigns should focus on enhancing the public’s knowledge about ASD treatment and etiology.

The Effect of Neonatal Sepsis on Risk of Autism Diagnosis

OBJECTIVE

 The study aimed to examine the association between neonatal sepsis and autism risk among children and whether the risk varied with the timing of exposure, child's sex, and race/ethnicity.

STUDY DESIGN

 We conducted a retrospective cohort study using electronic health records (EHR) extracted from Kaiser Permanente Southern California Health Care System. Mother-child dyads were constructed by linking records of children born to member mothers and continuing to receive care through the system during the follow-up period with those of their biological mothers (n = 469,789). Clinical health records were used to define neonatal sepsis. Diagnosis of autism was made by medical specialists. Potential confounders included maternal sociodemographic factors, obstetrical history, child's age, sex, race/ethnicity, and maternal and child medical history. Incident rates and adjusted hazard ratios (aHR) were used to estimate the associations.

RESULTS

 Compared with children without the diagnosis of autism, children with the condition were more likely to be from Asian/Pacific Islander descent and male sex. Exposed children showed higher rates of autism as compared with unexposed children (3.43 vs. 1.73 per 1,000 person-years, aHR: 1.67-95% confidence interval [CI]: 1.39-2.00). Both preterm (aHR: 1.47; 95% CI: 1.09-1.98) and term (aHR: 1.63; 95% CI: 1.29-2.06) births were associated with increased risk for autism. Although the magnitude of the HRs and incidence ratios for neonatal sepsis to increase autism risk varied between race ethnicities, neonatal sepsis was associated with significantly increased likelihood of autism diagnosis for all race-ethic groups except for Asian/Pacific Islanders. Although neonatal sepsis was associated with significantly increased autism risk for both boys and girls, incident rates and HR point estimates suggested that the effect may be stronger in girls.

CONCLUSION

 Neonatal sepsis is associated with increased risk of autism diagnosis in preterm- and term-born children. The association was significant for both girls and boys and all race ethnicities except for Asian-Pacific Islanders.

KEY POINTS

· Neonatal sepsis is associated with increased risk of autism diagnosis.. · The association was significant in preterm- and term-born children.. · The association was significant for all race/ethnicities except for Asian-Pacific Islanders..

Autism Spectrum Disorders in Children Exposed in Utero to Hyperemesis Gravidarum

OBJECTIVE

This study aimed to determine if hyperemesis gravidarum (HG) is associated with autism spectrum disorder (ASD) risk, and how this association is influenced by race, ethnicity, sex, exposure timing, and medication used to treat it.

STUDY DESIGN

This is a retrospective cohort study using records from 469,789 mother-child pairs who delivered at Kaiser Permanente Southern California (KPSC) hospital (1991-2014). Singleton-born children were followed longitudinally from 2 to 17 years of age. Clinical records were used to determine the diagnosis of HG and specialist-confirmed diagnosis of ASD.

RESULTS

Children exposed to HG in-utero had higher rates of ASD than unexposed children (2.87 vs. 1.71/1,000 person-years; adjusted hazard ratio [adj.HR]: 1.53; 95% confidence interval [CI]: 1.37-1.70). Children exposed at first and second trimester of pregnancies were more likely to develop ASD; 1.58-fold (95% CI: 1.40-1.79), and 1.36-fold (95% CI: 1.05-1.75), respectively, compared with unexposed children. HG was associated with ASD for boys (adj.HR: 1.50; 95% CI: 1.33-1.70) and girls (adj.HR: 1.62; 95% CI: 1.28-2.05). HG was significantly associated with ASD risk in white and Hispanic children. The medications used to treat HG did not contribute to ASD risk.

CONCLUSION

HG diagnosis is associated with ASD risk and may be helpful in identifying at-risk children who could benefit from enhanced surveillance and earlier diagnosis and intervention.

Autism spectrum disorder

Autism spectrum disorder is a construct used to describe individuals with a specific combination of impairments in social communication and repetitive behaviours, highly restricted interests and/or sensory behaviours beginning early in life. The worldwide prevalence of autism is just under 1%, but estimates are higher in high-income countries. Although gross brain pathology is not characteristic of autism, subtle anatomical and functional differences have been observed in post-mortem, neuroimaging and electrophysiological studies. Initially, it was hoped that accurate measurement of behavioural phenotypes would lead to specific genetic subtypes, but genetic findings have mainly applied to heterogeneous groups that are not specific to autism. Psychosocial interventions in children can improve specific behaviours, such as joint attention, language and social engagement, that may affect further development and could reduce symptom severity. However, further research is necessary to identify the long-term needs of people with autism, and treatments and the mechanisms behind them that could result in improved independence and quality of life over time. Families are often the major source of support for people with autism throughout much of life and need to be considered, along with the perspectives of autistic individuals, in both research and practice.

Recurrence Risk of Autism in Siblings and Cousins: A Multinational, Population-Based Study

OBJECTIVE

Familial recurrence risk is an important population-level measure of the combined genetic and shared familial liability of autism spectrum disorder (ASD). Objectives were to estimate ASD recurrence risk among siblings and cousins by varying degree of relatedness and by sex.

METHOD

This is a population-based cohort study of livebirths from 1998 to 2007 in California, Denmark, Finland, Israel, Sweden and Western Australia followed through 2011 to 2015. Subjects were monitored for an ASD diagnosis in their older siblings or cousins (exposure) and for their ASD diagnosis (outcome). The relative recurrence risk was estimated for different sibling and cousin pairs, for each site separately and combined, and by sex.

RESULTS

During follow-up, 29,998 cases of ASD were observed among the 2,551,918 births used to estimate recurrence in ASD and 33,769 cases of childhood autism (CA) were observed among the 6,110,942 births used to estimate CA recurrence. Compared with the risk in unaffected families, there was an 8.4-fold increase in the risk of ASD following an older sibling with ASD and a 17.4-fold increase in the risk of CA following an older sibling with CA. A 2-fold increase in the risk for cousin recurrence was observed for the 2 disorders. There also was a significant difference in sibling ASD recurrence risk by sex.

CONCLUSION

The present estimates of relative recurrence risks for ASD and CA will assist clinicians and families in understanding autism risk in the context of other families in their population. The observed variation by sex underlines the need to deepen the understanding of factors influencing ASD familial risk.

Prenatal Tetanus, Diphtheria, Acellular Pertussis Vaccination and Autism Spectrum Disorder

: media-1vid110.1542/5803567555001PEDS-VA_2018-0120Video Abstract BACKGROUND: Increasing vaccination of pregnant women makes it important to assess safety events potentially linked to prenatal vaccination. This study investigates the association between prenatal tetanus, diphtheria, acellular pertussis (Tdap) vaccination and autism spectrum disorder (ASD) risk in offspring.

METHODS

This is a retrospective cohort study of mother-child pairs with deliveries January 1, 2011 to December 31, 2014 at Kaiser Permanente Southern California hospitals. Maternal Tdap vaccination from pregnancy start to delivery date was obtained from electronic medical records. A diagnosis of ASD was obtained by using International Classification of Diseases, Ninth and Tenth Revision codes. Children were managed from birth to first ASD diagnosis, end of membership, or end of follow-up (June 30, 2017). Cox proportional hazards models estimated the unadjusted and adjusted hazard ratios (HRs) for the association between maternal Tdap vaccination and ASD, with inverse probability of treatment weighting to adjust for confounding.

RESULTS

Women vaccinated were more likely to be Asian American or Pacific Islander, be nulliparous, have a higher education, receive influenza vaccination prenatally, and give birth at term. ASD was diagnosed in 1341 (1.6%) children, and the incidence rate was 3.78 per 1000 person years in the Tdap exposed and 4.05 per 1000 person years in the unexposed group (HR: 0.98, 95% confidence interval: 0.88-1.09). The inverse probability of treatment weighting-adjusted analyses revealed that prenatal Tdap vaccination was not associated with an increased ASD risk (HR: 0.85, 95% confidence interval: 0.77-0.95).

CONCLUSIONS

Prenatal Tdap vaccination was not associated with an increased ASD risk. We support recommendations to vaccinate pregnant women to protect infants, who are at highest risk of death after pertussis infection.

Vaccination Patterns in Children After Autism Spectrum Disorder Diagnosis and in Their Younger Siblings

IMPORTANCE

In recent years, rates of vaccination have been declining. Whether this phenomenon disproportionately affects children with autism spectrum disorder (ASD) or their younger siblings is unknown.

OBJECTIVES

To investigate if children after receiving an ASD diagnosis obtain their remaining scheduled vaccines according to the Advisory Committee on Immunization Practices (ACIP) recommendations and to compare the vaccination patterns of younger siblings of children with ASD with the vaccination patterns of younger siblings of children without ASD.

DESIGN, SETTING, AND PARTICIPANTS

This investigation was a retrospective matched cohort study. The setting was 6 integrated health care delivery systems across the United States within the Vaccine Safety Datalink. Participants were children born between January 1, 1995, and September 30, 2010, and their younger siblings born between January 1, 1997, and September 30, 2014. The end of follow-up was September 30, 2015.

EXPOSURES

Recommended childhood vaccines between ages 1 month and 12 years.

MAIN OUTCOME AND MEASURE

The proportion of children who received all of their vaccine doses according to ACIP recommendations.

RESULTS

The study included 3729 children with ASD (676 [18.1%] female), 592 907 children without ASD, and their respective younger siblings. Among children without ASD, 250 193 (42.2%) were female. For vaccines recommended between ages 4 and 6 years, children with ASD were significantly less likely to be fully vaccinated compared with children without ASD (adjusted rate ratio, 0.87; 95% CI, 0.85-0.88). Within each age category, vaccination rates were significantly lower among younger siblings of children with ASD compared with younger siblings of children without ASD. The adjusted rate ratios varied from 0.86 for siblings younger than 1 year to 0.96 for those 11 to 12 years old. Parents who had a child with ASD were more likely to refuse at least 1 recommended vaccine for that child's younger sibling and to limit the number of vaccines administered during the younger sibling's first year of life.

CONCLUSIONS AND RELEVANCE

Children with ASD and their younger siblings were undervaccinated compared with the general population. The results of this study suggest that children with ASD and their younger siblings are at increased risk of vaccine-preventable diseases.

Association of Sex With Recurrence of Autism Spectrum Disorder Among Siblings

IMPORTANCE

Autism spectrum disorder (ASD) is known to be more prevalent among males than females in the general population. Although overall risk of recurrence of ASD among siblings has been estimated to be between 6.1% and 24.7%, information on sex-specific recurrence patterns is lacking.

OBJECTIVE

To estimate high-confidence sex-specific recurrence rates of ASD among siblings.

DESIGN, SETTING, AND PARTICIPANTS

This observational study used an administrative database to measure the incidence of ASD among children in 1 583 271 families (37 507 with at least 1 diagnosis of ASD) enrolled in commercial health care insurance plans at a large US managed health care company from January 1, 2008, through February 29, 2016. Families in the study had 2 children who were observed for at least 12 months between 4 and 18 years of age.

MAIN OUTCOMES AND MEASURES

The primary measure of ASD recurrence was defined as the diagnosis of ASD in a younger sibling of an older sibling with an ASD diagnosis.

RESULTS

Among the 3 166 542 children (1 547 266 females and 1 619 174 males; mean [SD] age, 11.2 [4.7] years) in the study, the prevalence of ASD was 1.96% (95% CI, 1.94%-1.98%) among males and 0.50% (95% CI, 0.49%-0.51%) among females. When a male was associated with risk in the family, ASD was diagnosed in 4.2% (95% CI, 3.8%-4.7%) of female siblings and 12.9% (95% CI, 12.2%-13.6%) of male siblings. When a female was associated with risk in the family, ASD was diagnosed in 7.6% (95% CI, 6.5%-8.9%) of female siblings and 16.7% (95% CI, 15.2%-18.4%) of male siblings.

CONCLUSIONS AND RELEVANCE

These findings are in agreement with the higher rates of ASD observed among males than among females in the general population. Our study provides more specific guidance for the screening and counseling of families and may help inform future investigations into the environmental and genetic factors that confer risk of ASD.

An Overview of Autism Spectrum Disorder, Heterogeneity and Treatment Options

Since the documented observations of Kanner in 1943, there has been great debate about the diagnoses, the sub-types, and the diagnostic threshold that relates to what is now known as autism spectrum disorder (ASD). Reflecting this complicated history, there has been continual refinement from DSM-III with 'Infantile Autism' to the current DSM-V diagnosis. The disorder is now widely accepted as a complex, pervasive, heterogeneous condition with multiple etiologies, sub-types, and developmental trajectories. Diagnosis remains based on observation of atypical behaviors, with criteria of persistent deficits in social communication and restricted and repetitive patterns of behavior. This review provides a broad overview of the history, prevalence, etiology, clinical presentation, and heterogeneity of ASD. Factors contributing to heterogeneity, including genetic variability, comorbidity, and gender are reviewed. We then explore current evidence-based pharmacological and behavioral treatments for ASD and highlight the complexities of conducting clinical trials that evaluate therapeutic efficacy in ASD populations. Finally, we discuss the potential of a new wave of research examining objective biomarkers to facilitate the evaluation of sub-typing, diagnosis, and treatment response in ASD.