Increased Risk Of Autism Spectrum Disorder Research Articles

Environmental Risk Factors in Autism Spectrum Disorder: A Narrative Review.

Existing evidence indicates that environmental factors might contribute up to 50% of the variance in autism spectrum disorder (ASD) risk. This structured narrative review offers a comprehensive synthesis of current knowledge on environmental risk factors in ASD, including evaluation of conflicting evidence, exploration of underlying mechanisms, and suggestions for future research directions. Analysis of diverse epidemiological investigations indicates that certain environmental factors, including advanced parental age, preterm birth, delivery complications, and exposure to toxic metals, drugs, air pollutants, and endocrine-disrupting chemicals, are linked to an increased ASD risk through various mechanisms such as oxidative stress, inflammation, hypoxia, and its consequences, changes in neurotransmitters, disruption of signaling pathways and some others. On the other hand, pregnancy-related factors such as maternal diabetes, maternal obesity, and caesarian section show a weaker association with ASD risk. At the same time, other environmental factors, such as vaccination, maternal smoking, or alcohol consumption, are not linked to the risk of ASD. Regarding nutritional elements data are inconclusive. These findings highlight the significance of environmental factors in ASD etiology and emphasize that more focused research is needed to target the risk factors of ASD. Environmental interventions targeting modifiable risk factors might offer promising avenues for ASD prevention and treatment.

عوامل الخطر قبل الولادة وأثناء الولادة و بعد الولادة المرتبطة باضطراب طيف التوحد في فلسطين: دراسة الحالات و الشواهد

Background: Autism spectrum disorder (ASD) is a multifactorial neurodevelopment disorder. Several prenatal, perinatal, and postnatal factors are suggested as risk factors for ASD. This study aimed to correlate prenatal, perinatal, and postnatal factors in a limited number of cases in Palestine. Methods: A case-control study involved 120 children (60 typically diagnosed with ASD and 60 healthy matched with the ASD group). The parents of the children in both groups were asked to fill out the questionnaire. Results: The study showed a higher male-to-female ratio in the ASD group. A family history of ASD was reported in 38.3% of the ASD group and 11.7% in the healthy group. Three prenatal risk factors, including maternal passive smoking, preserving follow-up prenatal visits, and experiencing psychological stress by mothers, were significantly associated with ASD. Most of the postnatal factors were significantly associated with increased ASD risk. The studied perinatal factors were not significantly associated with ASD. The parental factors, such as paternal age greater than 30 years and lower levels of education, displayed significant risk factors associated with ASD. Conclusion: This study found significant associations between several prenatal, postnatal, and parental factors and ASD in a sample of Palestinian children. المقدمة: اضطراب طيف التوحد هو اضطراب نمائي عصبي متعدد العوامل. تم تحديد العديد من العوامل قبل الولادة و أثناء الولادة و بعد الولادة كعوامل قد تكون مرتبطة بالاصابة باضطراب طيف التوحد. هدفت هذه الدراسة لفحص ارتباط عدة عوامل قبل الولادة و أثناء الولادة و بعد الولادة في عدد محدود من حالات التوحد في فلسطين. المنهجية: تمت الدراسة من خلال جمع معلومات من عينة ضمت 120 طفل (60 تم تشخيصهم بطيف التوحد و 60 طفل سليم و متطابقين مع مجموعة التوحد). تمت الاجابة على الاستبيان من قبل أولياء الأمور في المجموعتين. النتائج: أظهرت الدراسة أن نسبة الذكور الى الاناث في مجموعة طيف التوحد كانت أعلى. تم تحديد نسبة وجود تاريخ عائلي في 38.3% من مجموعة طيف التوحد و 11.7% من مجموعة الاطفال السليمين. تم تحديد ثلاثة عوامل خطورة قبل الولادة مرتبطة بشكل وثيق مع اضطراب طيف التوحد و تشمل التدخين السلبي للأم، متابعة زيارات الرعاية قبل الولادة، و التعرص للاجهاد النفسي من قبل الأمهات. معظم عوامل الخطر بعد الولادة كانت مرتبطة بشكل وثيق بزيادة خطر الاصابة بطيف التوحد. عوامل الخطر أثناء الولادة التي تمت دراستها لم ترتبط بشكل وثيق باضطراب طيف التوحد. العوامل المتعلقة بالوالدين مثل عمر الأب أكثر من 30 عام و مستويات التعليم المتدنية أظهرت ارتباطا وثيقا بالإصابة بطيف التوحد. الاستنتاج: وجدت الدراسة ارتباطات وثيقة بين عدة عوامل قبل الولادة و أثناء الولادة و بعد الولادة مع طيف التوحد في عينة من الأطفال الفلسطينيين.

Associations between brake and tire wear-related PM2.5 metal components, particulate oxidative stress potential, and autism spectrum disorder in Southern California

BackgroundAir pollution is a global health concern, with fine particulate matter (PM2.5) constituents posing potential risks to human health, including children's neurodevelopment. Here we investigated associations between exposure during pregnancy and infancy to specific traffic-related PM2.5 components with Autism Spectrum Disorder (ASD) diagnosis. MethodsFor exposure assessment, we estimated PM2.5 components related to traffic exposure (Barium [Ba] as a marker of brake dust and Zinc [Zn] as a tire wear marker, Black Carbon [BC]) and oxidative stress potential (OSP) markers (Hydroxyl Radical [OPOH] formation, Dithiothreitol activity [OPDTT], reactive oxygen species [ROS]) modeled with land use regression with co-kriging based on an intensive air monitoring campaign. We assigned exposures to a cohort of 444,651 children born in Southern California between 2016 and 2019, among whom 11,466 ASD cases were diagnosed between 2018 and 2022, Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained with logistic regression for single pollutant and PM2.5 mass co-adjusted models, also adjusting for sociodemographic characteristics. ResultsAmong PM2.5 components, we found the strongest positive association with ASD for our brake wear marker Ba (ORper IQR = 1.29, 95 % CI: 1.24, 1.34). This was followed by an increased risk for all PM2.5 oxidative stress potential markers; the strongest association was with ROS formation (ORper IQR = 1.22, 95 % CI: 1.18, 1.25). PM2.5 mass was linked to ASD in Hispanic and Black children, but not White children, while traffic-related PM2.5 and OSP markers increased ASD risk across all groups. In neighborhoods with the lowest socioeconomic status (SES), associations with ASD were stronger for all examined pollutants compared to higher SES areas. ConclusionsOur findings suggest that brake wear-related PM2.5 and PM2.5 OSP are associated with ASD diagnosis in Southern California. These results suggest that strategies aimed at reducing the public health impacts of PM2.5 need to consider specific sources.

Association Between Estimated Geocoded Residential Maternal Exposure to Lithium in Drinking Water and Risk for Autism Spectrum Disorder in Offspring in Denmark

Lithium is a naturally occurring and trace element that has mood-stabilizing effects. Maternal therapeutic use of lithium has been associated with adverse birth outcomes. In animal models, lithium modulates Wnt/β-catenin signaling that is important for neurodevelopment. It is unknown whether exposure to lithium in drinking water affects brain health in early life. To evaluate whether autism spectrum disorder (ASD) in offspring is associated with maternal exposure to lithium in drinking water during pregnancy. This nationwide population-based case-control study in Denmark identified 8842 children diagnosed with ASD born from 2000 through 2013 and 43 864 control participants matched by birth year and sex from the Danish Medical Birth Registry. These data were analyzed from March 2021 through November 2022. Geocoded maternal residential addresses during pregnancy were linked to lithium level (range, 0.6 to 30.7 μg/L) in drinking water estimated using kriging interpolation based on 151 waterworks measurements of lithium across all regions in Denmark. ASD diagnoses were ascertained using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes recorded in the Danish Psychiatric Central Register. The study team estimated odds ratios (ORs) and 95% CIs for ASD according to estimated geocoded maternal exposure to natural source of lithium in drinking water as a continuous (per IQR) or a categorical (quartile) variable, adjusting for sociodemographic factors and ambient air pollutants levels. The study team also conducted stratified analyses by birth years, child's sex, and urbanicity. A total of 8842 participants with ASD (male, 7009 [79.3%]) and 43 864 control participants (male, 34 749 [79.2%]) were studied. Every IQR increase in estimated geocoded maternal exposure to natural source of lithium in drinking water was associated with higher odds for ASD in offspring (OR, 1.23; 95% CI, 1.17-1.29). Elevated odds among offspring for ASD were estimated starting from the second quartile (7.36 to 12.67 μg/L) of estimated maternal exposure to drinking water with lithium and the OR for the highest quartile (more than 16.78 μg/L) compared with the reference group (less than 7.39 μg/L) was 1.46 (95% CI, 1.35-1.59). The associations were unchanged when adjusting for air pollution exposures and no differences were apparent in stratified analyses. Estimated maternal prenatal exposure to lithium from naturally occurring drinking water sources in Denmark was associated with an increased ASD risk in the offspring. This study suggests that naturally occurring lithium in drinking water may be a novel environmental risk factor for ASD development that requires further scrutiny.

Preeclampsia Onset, Days to Delivery, and Autism Spectrum Disorders in Offspring: Clinical Birth Cohort Study.

Maternal preeclampsia is associated with a risk of autism spectrum disorders (ASD) in offspring. However, it is unknown whether the increased ASD risk associated with preeclampsia is due to preeclampsia onset or clinical management of preeclampsia after onset, as clinical expectant management of preeclampsia allows pregnant women with this complication to remain pregnant for potentially weeks depending on the onset and severity. Identifying the risk associated with preeclampsia onset and exposure provides evidence to support the care of high-risk pregnancies and reduce adverse effects on offspring. This study aimed to fill the knowledge gap by assessing the ASD risk in children associated with the gestational age of preeclampsia onset and the number of days from preeclampsia onset to delivery. This retrospective population-based clinical cohort study included 364,588 mother-child pairs of singleton births between 2001 and 2014 in a large integrated health care system in Southern California. Maternal social demographic and pregnancy health data, as well as ASD diagnosis in children by the age of 5 years, were extracted from electronic medical records. Cox regression models were used to assess hazard ratios (HRs) of ASD risk in children associated with gestational age of the first occurrence of preeclampsia and the number of days from first occurrence to delivery. Preeclampsia occurred in 16,205 (4.4%) out of 364,588 pregnancies; among the 16,205 pregnancies, 2727 (16.8%) first occurred at <34 weeks gestation, 4466 (27.6%) first occurred between 34 and 37 weeks, and 9012 (55.6%) first occurred at ≥37 weeks. Median days from preeclampsia onset to delivery were 4 (IQR 2,16) days, 1 (IQR 1,3) day, and 1 (IQR 0,1) day for those first occurring at <34, 34-37, and ≥37 weeks, respectively. Early preeclampsia onset was associated with greater ASD risk (P=.003); HRs were 1.62 (95% CI 1.33-1.98), 1.43 (95% CI 1.20-1.69), and 1.23 (95% CI 1.08-1.41), respectively, for onset at <34, 34-37, and ≥37 weeks, relative to the unexposed group. Within the preeclampsia group, the number of days from preeclampsia onset to delivery was not associated with ASD risk in children; the HR was 0.995 (95% CI 0.986-1.004) after adjusting for gestational age of preeclampsia onset. Preeclampsia during pregnancy was associated with ASD risk in children, and the risk was greater with earlier onset. However, the number of days from first preeclampsia onset to delivery was not associated with ASD risk in children. Our study suggests that ASD risk in children associated with preeclampsia is not increased by expectant management of preeclampsia in standard clinical practice. Our results emphasize the need to identify effective approaches to preventing the onset of preeclampsia, especially during early pregnancy. Further research is needed to confirm if this finding applies across different populations and clinical settings.

Prenatal exposure to tailpipe and non-tailpipe tracers of particulate matter pollution and autism spectrum disorders

BackgroundTraffic-related air pollution exposure is associated with increased risk of autism spectrum disorder (ASD). It is unknown whether carbonaceous material from vehicular tailpipe emissions or redox-active non-tailpipe metals, eg. from tire and brake wear, are responsible. We assessed ASD associations with fine particulate matter (PM2.5) tracers of tailpipe (elemental carbon [EC] and organic carbon [OC]) and non-tailpipe (copper [Cu]; iron [Fe] and manganese [Mn]) sources during pregnancy in a large cohort. MethodsThis retrospective cohort study included 318,750 children born in Kaiser Permanente Southern California (KPSC) hospitals during 2001–2014, followed until age 5. ASD cases were identified by ICD codes. Monthly estimates of PM2.5 and PM2.5 constituents EC, OC, Cu, Fe, and Mn with 4 km spatial resolution were obtained from a source-oriented chemical transport model. These exposures and NO2 were assigned to each maternal address during pregnancy, and associations with ASD were assessed using Cox regression models adjusted for covariates. PM constituent effect estimates were adjusted for PM2.5 and NO2 to assess independent effects. To distinguish ASD risk associated with non-tailpipe from tailpipe sources, the associations with Cu, Fe, and Mn were adjusted for EC and OC, and vice versa. ResultsThere were 4559 children diagnosed with ASD. In single-pollutant models, increased ASD risk was associated with gestational exposures to tracers of both tailpipe and non-tailpipe emissions. The ASD hazard ratios (HRs) per inter-quartile increment of exposure) for EC, OC, Cu, Fe, and Mn were 1.11 (95% CI: 1.06–1.16), 1.09 (95% CI: 1.04–1.15), 1.09 (95% CI: 1.04–1.13), 1.14 (95% CI: 1.09–1.20), and 1.17 (95% CI: 1.12–1.22), respectively. Estimated effects of Cu, Fe, and Mn (reflecting non-tailpipe sources) were largely unchanged in two-pollutant models adjusting for PM2.5, NO2, EC or OC. In contrast, ASD associations with EC and OC were markedly attenuated by adjustment for non-tailpipe sources. ConclusionResults suggest that non-tailpipe emissions may contribute to ASD. Implications are that reducing tailpipe emissions, especially from vehicles with internal combustion engines, may not eliminate ASD associations with traffic-related air pollution.

BENIGN ENLARGEMENT OF SUBARACHNOID SPACES IN INFANTS

Benign enlargement of subarachnoid spaces (BESS) constitutes is one of the most frequent neurosonographic findings in infancy and is considered to regress spontaneously by the age of 2 years. Although the majority of children with BESS demonstrate normal developmental milestones, some patients may experience a transient psychomotor delay under the age of 2 year. Besides clinical andneuroimaging findings, the long-term impact of BESS is of great interest (learning difficulties at school, language delay, impairmentsin social-cognitive abilities, reduced quality of life, decreased attention skills and poor visual-motor performance, increased risk ofautism spectrum disorders as well as a higher incidence of epilepsy). It is considered that the risk of long-term consequences may be associated with pathogenetic features of dilation of extra-axial cerebrospinal fluid spaces. In this review, we describe potentialpathogenetic mechanisms of dilatation of the subarachnoid space and its pathological sequelae in children. Generally, numerous pathogenetic hypotheses about developing BESS have been proposed as follows: remarkable physiological imbalance between the skull and brain growth in infants aged from three months to one year; manifestation of cerebral trophy; communicating hydrocephalus due to a distal block with a valve mechanism; a delay in maturation of arachnoid villi/granulations until two years of age; the result of abusive head trauma in infants. However, the hypothesis about pathological consequences of BESS in the long run due to abnormalvenous hemodynamics has emerged in recent years. Impaired venous outflow is the main driving factor of subarachnomegaly and the more severe pathological changes the more significant symptoms of subarachnomegaly. We also highlight the role of impaired cerebralvenous circulation in the development of subarachnomegaly. Further studies are needed to investigate the clinical relevance of chronic increased intracranial pressure due to venous outflow disturbance in infants with enlarged subarachnoid spaces.Тhe subject for future research should be to determine a diagnostic algorithm to help distinguish patients with BESS from those who are at risk of impairedneurological development and require additional diagnostic and therapeutic interventions.

Migration modulates the prevalence of ASD and ADHD: a systematic review and meta-analysis

BackgroundMigration has been implicated as a risk factor for autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), but evidence is still limited and inconsistent. We aim to investigate the relationship between migration status and risk of ASD and ADHD.MethodsElectronic databases including PubMed, EMBASE, Web of Science, and PsychINFO were searched to identify observational studies on this topic, from inception to February 2021. Random-effects meta-analysis models were used to pool the summary odds ratio (OR) and 95% confidence interval (95% CI), and subgroup analyses were conducted to detect possible discrepancies in associations. Certainty of evidence was assessed as per the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) guidelines.ResultsA total of 13 studies (6,532,546 participants) for ASD, five studies (2,875,070 participants) for ADHD, and six studies (31,158 participants) for hyperactivity were included. Overall, the pooled results indicated that migration was associated with increased risk of ASD (pooled OR: 1.32; 95% CI: 1.07–1.63; P for Z test = 0.010), but no association was found between migration and ADHD (pooled OR: 0.84; 95% CI: 0.53–1.32; P for Z test = 0.452) or hyperactivity (pooled standardized mean difference: -0.073; 95% CIs: − 0.383–0.236; P for Z test = 0.642). Subgroup analyses further demonstrated that maternal migration was ASD risk factor (pooled OR: 1.49; 95% CI: 1.19–1.87), and migrant children were more likely to develop ASD with comorbid intellectual disability (ID) (pooled OR: 1.21, P for interaction = 0.006) than ASD without ID. After standardized the origin of migrants, European migrant children from Americas were at higher risk of ASD and ADHD (pooled OR were 4.13 and 1.26), and increased ASD risk was also observed in African children (pooled OR: 2.72). The GRADE of evidence was very low.ConclusionsMaternal migration is a risk factor for ASD, and migrant ASD children are more likely comorbid ID. The role of migration on ADHD remains controversial, more studies are needed to assess the association between migration status and ADHD. Health care practitioners should consider screening and providing extra resources for migrant children.

Maternal type1 diabetes, pre-term birth and risk of autism spectrum disorder-a prospective cohort study.

It has been suggested that maternal type 1 diabetes (T1D) increases the risk of autism spectrum disorder (ASD) in the offspring. However, it is unclear whether this risk is mediated by pre-term birth, affecting around one-third of pregnancies with T1D, and whether maternal levels of glycated haemoglobin (HbA1c) impact the risk. A cohort of 1.4 million Swedish children born between 1998 and 2015, and their parents. Maternal T1D and HbA1c before or in early pregnancy, gestational and ASD diagnoses were obtained from Swedish national registers. Relative risk (RR) and 95% CIs of ASD were estimated by hazard ratios (HRs) from Cox regression or RR from log-binomial regression. Of 1 406 650 children, 8003 (0.6%) were born to mothers with T1D, 24941 (1.8%) were diagnosed with ASD and 81915 (5.8%) were born pre-term. The risk of ASD was increased in offspring of mothers with T1D was HR = 1.40 (1.21-1.61). The RR for each +5-mmol/mol excess HbA1c was estimated at HR = 1.03 (0.97-1.10). The T1D effect on ASD mediated through pre-term birth was estimated at RR = 1.06 (1.05 to 1.08), corresponding to 22% (16% to 41%) of the total effect. T1D in pregnancy was associated with increased ASD risk in the offspring. Twenty percent of the total effect was accounted for by pre-term birth. HbA1c was not associated with ASD risk, beyond the risk associated by the T1D diagnosis itself. Awareness of ASD in the offspring of mothers with T1D may be warranted, especially considering the additional effect of pre-term birth.

Prenatal Exposure to Air Pollution and Autism Spectrum Disorder: Sensitive Windows of Exposure and Sex Differences.

Background:Studies have shown that air pollution exposures during pregnancy are associated with an increased risk of autism spectrum disorder (ASD) in children, and the risk appears to be greater for boys. However, studies assessing gestational windows of susceptibility have been mostly limited by trimesters.Objective:We identified sensitive windows of exposure to regional air pollution and risk of ASD and examined sex differences in a large birth cohort.Methods:This population-based retrospective cohort study included 294,937 mother–child pairs with singleton deliveries in Kaiser Permanente Southern California (KPSC) hospitals from 2001 to 2014. Children were followed using electronic medical records until clinical ASD diagnosis, non-KPSC membership, death, or 31 December 2019, whichever came first. Weekly mean fine particulate matter [PM with an aerodynamic diameter of ()], nitrogen dioxide (), and ozone () pregnancy exposures were estimated using spatiotemporal prediction models. Cox proportional hazard models with distributed lags were used to estimate weekly pollutant exposure associations with ASD risk for the entire cohort, and separately for boys and for girls. Models were adjusted for child sex (for full cohort), maternal race/ethnicity, maternal age at delivery, parity, maternal education, maternal comorbidities, medical center, census tract median household income, birth year, and season.Results:There were 5,694 ASD diagnoses (4,636 boys, 1,058 girls). Sensitive exposure windows associated with ASD were found early in pregnancy, statistically significant throughout the first two trimesters [1–27 wk of gestation, cumulative [95% confidence interval (CI): 1.06, 1.23] per interquartile range (IQR) () increase]. exposure during 34–37 wk of gestation was associated with increased risk [ (95% CI: 1.01, 1.11) per IQR () increase] but with reduced risk during 20–28 wk of gestation [ (95% CI: 0.89, 0.98)]. No associations were observed with . Sex-stratified early gestational associations were stronger among boys [boys (95% CI: 1.08, 1.26); girls (95% CI: 0.89, 1.26)]. associations in later gestation were observed only in boys [boys (95% CI: 1.04, 1.16); girls (95% CI: 0.84, 1.05)].Conclusions:Exposures to in the first two gestational trimesters were associated with increased ASD risk in children, with stronger associations observed for boys. The role of exposure on ASD risk merits further investigation. https://doi.org/10.1289/EHP9509

Prediction of Autism Risk From Family Medical History Data Using Machine Learning: A National Cohort Study From Denmark

BackgroundA family history of specific disorders (e.g., autism, depression, epilepsy) has been linked to risk for autism spectrum disorder (ASD). This study examines whether family history data could be used for ASD risk prediction. MethodsWe followed all Danish live births, from 1980 to 2012, of Denmark-born parents for an ASD diagnosis through April 10, 2017 (N = 1,697,231 births; 26,840 ASD cases). Linking each birth to three-generation family members, we identified 438 morbidity indicators, comprising 73 disorders reported prospectively for each family member. We tested various models using a machine learning approach. From the best-performing model, we calculated a family history risk score and estimated odds ratios and 95% confidence intervals for the risk of ASD. ResultsThe best-performing model comprised 41 indicators: eight mental conditions (e.g., ASD, attention-deficit/hyperactivity disorder, neurotic/stress disorders) and nine nonmental conditions (e.g., obesity, hypertension, asthma) across six family member types; model performance was similar in training and test subsamples. The highest risk score group had 17.0% ASD prevalence and a 15.3-fold (95% confidence interval, 14.0–17.1) increased ASD risk compared with the lowest score group, which had 0.6% ASD prevalence. In contrast, individuals with a full sibling with ASD had 9.5% ASD prevalence and a 6.1-fold (95% confidence interval, 5.9–6.4) higher risk than individuals without an affected sibling. ConclusionsFamily history of multiple mental and nonmental conditions can identify more individuals at highest risk for ASD than only considering the immediate family history of ASD. A comprehensive family history may be critical for a clinically relevant ASD risk prediction framework in the future.

Autism risk in neonatal intensive care unit patients associated with novel heart rate patterns.

Background:Neonatal Intensive Care Unit (NICU) patients are at increased risk for autism spectrum disorder (ASD). Autonomic nervous system aberrancy has been described in children with ASD, and we aimed to identify heart rate (HR) patterns in NICU patients associated with eventual ASD diagnosis.Methods:This retrospective cohort study included NICU patients from 2009-2016 with archived HR data and follow-up beyond age 3 years. Medical records provided clinical variables and ASD diagnosis. HR data were compared in infants with and without ASD.Results:Of 2371 patients, 88 had ASD, and 689,016 hours of data were analyzed. HR skewness (HRskw) was significantly different between ASD and control infants. Preterm infants at early postmenstrual ages (PMA) had negative HRskw reflecting decelerations, which increased with maturation. From 34-42 weeks PMA, positive HRskw toward accelerations was higher in males with ASD. In 931 males with at least 4 days of HR data, overall ASD prevalence was 5%, whereas 11% in the top 5th HRskw percentile had ASD.Conclusion:High HRskw in NICU males, perhaps representing autonomic imbalance, was associated with increased ASD risk. Further study is needed to determine whether HR analysis identifies highest risk infants who might benefit from earlier screening and therapies.

859 Sex hormone-binding globulin is decreased in hypertensive pregnancies with offspring affected by autism spectrum disorder

To determine whether sex hormone-binding globulin (SHBG) steroid dysregulation is associated with autism spectrum disorder (ASD) in hypertensive pregnancies. SHBG concentrations were measured in second trimester serum of women enrolled in Utah’s First and Second Trimester Evaluation of Risk (FASTER) study, a multi-center cohort study for aneuploidy screening. ASD case status was determined by linking offspring to an ASD master case list within the Utah Population Database. Obstetric variables (e.g., gestational age, maternal age, pregnancy weight gain, pre-pregnancy BMI, gestational/pre-existing diabetes, and hypertension) were abstracted from birth certificate data. The relationship between SHBG levels and offspring ASD case status was analyzed using multivariate logistic regression for pregnancies complicated by hypertension. Covariates include the remaining obstetric variables listed above. SHBG levels were significantly lower in hypertensive pregnancies associated with ASD among offspring (mean=137.11 nmol/L, 95% CI 117.56 - 156.66 vs. mean=220.45 nmol/L, 95% CI 168.56 - 272.34, ASD vs. without ASD, respectively). Previous studies have demonstrated the association between prenatal metabolic syndrome (PNMS) and increased ASD risk, while other investigations have linked decreased serum SHBG levels to insulin resistance and ASD co-occurrence. It is unclear which component medical condition of PNMS – hypertension, diabetes, or obesity – is the primary variable driving the association between ASD and PNMS as these variables are frequently comorbid. This study concludes that lower SHBG levels are associated with ASD in offspring of hypertensive pregnancies after controlling for confounding variables. SHBG should be included in future serum biomarker studies investigating the link between ASD and PNMS.

Prenatal exposure to per- and polyfluoroalkyl substances in association with autism spectrum disorder in the MARBLES study

BackgroundPrenatal exposure to per- and polyfluoroalkyl substances (PFAS) has shown potential to adversely affect child brain development, but epidemiologic evidence remains inconsistent. We examined whether prenatal exposure to PFAS was associated with increased risk of autism spectrum disorder (ASD). MethodsParticipants were 173 mother–child pairs from MARBLES (Markers of Autism Risk in Babies – Learning Early Signs), a high-risk ASD cohort. At 3 years old, children were clinically confirmed for ASD and classified into ASD (n = 57) and typical development (TD, n = 116). We quantified nine PFAS in maternal serum collected during pregnancy. We examined associations of ASD with individual PFAS as well as the combined effect of PFAS on ASD using scores of the first principal component (PC-1) accounting for the largest variance. ResultsPrenatal perfluorooctanoate (PFOA) and perfluorononanoate (PFNA) showed positive associations (per 2-fold relative increase in concentration: relative risk (RR) = 1.20, 95% CI: 0.90, 1.61 [PFOA]; RR = 1.24, 95% CI: 0.91, 1.69 [PFNA]), while perfluorohexane sulfonate (PFHxS) showed a negative association (RR = 0.88, 95% CI: 0.77, 1.01) with ASD risk. When examining associations of ASD with untransformed PFAS concentrations, PFOA, PFNA, and PC-1 were associated with increased ASD risk (per nanogram per milliliter increase: RR = 1.31, 95% CI: 1.04, 1.65; RR = 1.79, 95% CI: 1.13, 2.85; RR = 1.10, 95% CI: 0.97, 1.25, respectively), while the RR of PFHxS moved toward the null. ConclusionsFrom this high-risk ASD cohort, we observed increased risk of ASD in children exposed to PFOA and PFNA. Further studies should be conducted in the general population because this population may have a larger fraction of cases resulting from genetic sources.

Associations between preterm birth and low birth weight in parents and autism spectrum disorder (ASD) risk in their offspring: A population-based multigenerational cohort study in Denmark

Background: Fetal exposure risk factors are associated with increased ASD risk. New hypotheses regarding transgenerational risk for ASD have been proposed, but epidemiological evidence is still lacking. We evaluated whether parental preterm birth or low birth weight was associated with ASD risk in offspring.Methods: We conducted a nationwide register-based cohort study that included 230,174 mother-child and 157,926 father-child pairs in Denmark. Logistic regression models were used to estimate Odds Ratios (OR) and 95% confidence intervals (CI) for offspring ASD according to the parental preterm (&lt;37 weeks) and low birth weight (&lt;2500 grams) status, with or without adjustment for grandmaternal sociodemographic factors. Mediation analyses were performed for selected parental and offspring health-related factors.Results: Offspring of mothers or fathers with adverse birth outcomes had about 31-43% higher risk for ASD (maternal preterm birth, OR=1.31, 95% CI= 1.12,1.55; maternal low birth weight, OR=1.35, 95% CI: 1.17,1.57; paternal preterm birth, OR=1.43, 95% CI=1.18, 1.73; paternal low birth weight, OR=1.38, 95% CI= 1.13, 1.70). Parents born very preterm (&lt;32 weeks) marked a nearly 2-fold increase in ASD risk in their children. These associations were slightly attenuated upon adjustment for grandmaternal sociodemographic factors. Mediation analyses suggested a small magnitude of indirect effect of parental social-mental and offspring perinatal risk factors on the child, especially for maternal birth outcome associations.Conclusions: Offspring of parents born with adverse outcomes had an elevated risk for ASD. Transgenerational risk for ASD through maternal and paternal factors should be considered in future research on ASD etiology.

Association Between Epidural Analgesia During Labor and Risk of Autism Spectrum Disorders in Offspring

Although the safety of labor epidural analgesia (LEA) for neonates has been well documented, the long-term health effects of LEA on offspring remain to be investigated. To assess the association between maternal LEA exposure and risk of autism spectrum disorders (ASDs) in offspring. Data for this retrospective longitudinal birth cohort study were derived from electronic medical records from a population-based clinical birth cohort. A total of 147 895 singleton children delivered vaginally between January 1, 2008, and December 31, 2015, in a single integrated health care system were included. Children were followed up from the age of 1 year until the first date of the following occurrences: clinical diagnosis of ASD, last date of health plan enrollment, death, or the study end date of December 31, 2018. Use and duration of LEA. The main outcome was clinical diagnosis of ASD. Cox proportional hazards regression analysis was used to estimate the hazard ratio (HR) of ASD associated with LEA exposure. Among the cohort of 147 895 singleton children (74 425 boys [50.3%]; mean [SD] gestational age at delivery, 38.9 [1.5] weeks), 109 719 (74.2%) were exposed to maternal LEA. Fever during labor was observed in 13 055 mothers (11.9%) in the LEA group and 510 of 38 176 mothers (1.3%) in the non-LEA group. Autism spectrum disorders were diagnosed in 2039 children (1.9%) in the LEA group and 485 children (1.3%) in the non-LEA group. After adjusting for potential confounders, including birth year, medical center, maternal age at delivery, parity, race/ethnicity, educational level, household income, history of comorbidity, diabetes during pregnancy, smoking during pregnancy, preeclampsia or eclampsia, prepregnancy body mass index, gestational weight gain, gestational age at delivery, and birth weight, the HR associated with LEA vs non-LEA exposure was 1.37 (95% CI, 1.23-1.53). Relative to the unexposed group, the adjusted HR associated with LEA exposure of less than 4 hours was 1.33 (95% CI, 1.17-1.53), with LEA exposure of 4 to 8 hours was 1.35 (95% CI, 1.20-1.53), and with LEA exposure of more than 8 hours was 1.46 (95% CI, 1.27-1.69). Within the LEA group, there was a significant trend of ASD risk associated with increasing duration of LEA exposure after adjusting for covariates (HR for linear trend, 1.05 [95% CI, 1.01-1.09] per 4 hours). Adding fever to the model did not change the HR estimate associated with LEA exposure (adjusted HR for LEA vs non-LEA, 1.37 [95% CI, 1.22-1.53]). This study suggests that maternal LEA may be associated with increased ASD risk in children. The risk appears to not be directly associated with epidural-related maternal fever.

Childhood vaccination as a protective factor for developmental psychopathology

BackgroundsDespite multiple studies demonstrating no relationship between childhood vaccination and increasing Autism Spectrum Disorder (ASD) prevalence, parental fear for vaccination and subsequent refusal to vaccinate their children continue, resulting in recent outbreaks of childhood infections such as measles in the US. We examine the relationship between the completion of 6 recommended vaccinations in childhood and the likelihood for having developmental psychopathology. MethodsTwo large-scale South Korean epidemiologic samples were used to examine whether completion of childhood vaccinations decrease likelihood of having ASD as assessed by Autism Spectrum Screening Questionnaire (ASSQ) and behavioral problems scores. Parental reports on vaccination completion were categorized in groups: <3, 4−5, & 6. The primary outcome is the likelihood of having ASD and/or, internalizing, and externalizing behavioral symptoms. Likelihood of having ASD was categorized as: low (ASSQ < 10), intermediate (ASSQ = 10–14), and high (ASSQ ≥ 15). The risk for externalizing/internalizing symptoms was assessed with the Behavior Assessment System for Children-Parent Rating Scale. We examined the hypothesis in a Discovery Sample (DS) (N = 10,006) and verified findings in a Replication Sample (RS) (N = 29,381). Results84.3 % of DS and 80.1 % of RS participants were fully vaccinated. In the DS, after adjusting for demographics and confounders, children with incomplete-vaccinations were at greater risk for ASD when compared to those fully vaccinated (adjusted odds ratio [aOR] = 1.42, 95 % Confidence Interval [CI] 1.17−1.73 with 4−5 vaccinations; aOR = 2.33, CI 1.53−3.56 with vaccination <3). The DS finding was confirmed in the RS (aOR = 1.44, CI 1.32−1.58 with 4−5 vaccinations and aOR = 2.19, CI 1.80−2.67 with < 3 vaccinations). In the DS, those with incomplete-vaccinations were at a greater risk for internalizing and externalizing symptoms. ConclusionsWe replicate our own and prior findings that vaccination does not increase ASD risk. Further, completing recommended vaccinations may offer protection against the risk of having ASD and other developmental psychopathology.

Maternal Thyroid Disorders and Risk of Autism Spectrum Disorder in Progeny.

Maternal thyroid dysfunction is suspected of causing adverse neurodevelopmental effects, but current evidence is inconclusive. Epidemiologic investigations generally suggest an association between maternal thyroid dysfunction and neurodevelopment impairments in progeny, but clinical trials of thyroid treatment during pregnancy reported null effects. To better understand these discrepant findings, we evaluated the association between maternal thyroid conditions and autism spectrum disorder (ASD), including examining the role of gestational thyroid-related hormone concentrations and thyroid medications use. Analyses considered 437,222 singleton live births occurring in a large Israeli health fund in 1999-2013, followed through 2016. Thyroid conditions and ASD cases were identified through International Classification of Diseases-9 codes with subsequent validation through review of medical records. Laboratory gestational thyroid hormone measurements were also considered. Children of mothers who ever experienced hypothyroidism had a higher risk of ASD compared with children of mothers without hypothyroidism (adjusted odds ratio [aOR] = 1.26, 95% confidence interval [CI] = 1.12, 1.42). The association with hyperthyroidism was less consistent, but elevated in main analyses (aOR = 1.42, 95% CI = 1.04, 1.94). These associations were not explained by maternal gestational thyroid hormones levels nor mitigated by gestational use of thyroid medications. Results indicate that maternal thyroid conditions are associated with increased ASD risk in progeny, but suggestively not due to direct effects of thyroid hormones. Instead, factors that influence maternal thyroid function could have etiologic roles in ASD through pathways independent of maternal gestational thyroid hormones and thus be unaffected by medication treatment. Factors known to disrupt thyroid function should be examined for possible involvement in ASD etiology.

Association of Grandparental and Parental Age at Childbirth With Autism Spectrum Disorder in Children

Advanced parental age has been associated with autism spectrum disorders (ASDs) in children. However, little is known about the association between grandparental age at the time of birth of the parent and the risk of ASD in the grandchildren. To estimate the associations between parental and grandparental age and ASD risk in children. This population-based, multigenerational cohort study used data from Danish national health registries. A parental age cohort was constructed to evaluate the association between parental age and ASD in 1 476 783 singleton children born from 1990 to 2013, and a multigenerational cohort was also constructed including 362 438 fathers and 458 234 mothers born from 1973 to 1990 for whom information on grandparental age was available. Data analyses were conducted from November 1, 2018, through February 7, 2020. Parental age at childbirth and grandparental age at the time of the birth of the parent. Diagnoses of ASD in children were obtained from the Danish Psychiatric Central Register (1994-2017). Logistic regression analysis was used to estimate the associations between parental or grandparental age and ASD in children. Of the 1 476 783 children born from 1990 to 2013, 758 066 (51.3%) were male, and 27 616 (1.9%) had ASD (20 467 [74.1%] were male). Advanced paternal or maternal age over 30 years was monotonically associated with increased ASD risk, with odds ratios (ORs) of 1.56 (95% CI, 1.45-1.68) for maternal age 40 years and older and 1.57 (95% CI, 1.39-1.78) for paternal age 50 years and older, compared with parents aged 25 to 29 years. In the multigenerational cohort, 9364 grandchildren (1.7%) had ASD. This study found U-shaped associations, in that ASD risk was higher among grandchildren of younger (≤19 years) maternal grandmothers (OR, 1.68; 95% CI, 1.52-1.85), younger maternal grandfathers (OR, 1.50; 95% CI, 1.26-1.78), and younger paternal grandmothers (OR, 1.18; 95% CI, 1.04-1.34), and older (≥40 years) paternal grandmothers (OR, 1.40; 95% CI, 1.03-1.90) compared with the grandchildren of grandparents who were aged 25 to 29 years at the time of giving birth to the parents. These findings corroborate previous studies suggesting that advanced parental age is independently associated with increased ASD risk in children. This study also found that children with young maternal grandparents and children with young and old paternal grandparents had elevated ASD risk. Possible transmission of ASD risk across generations should be considered in etiological research on ASD.

Gestational diabetes mellitus, prenatal air pollution exposure, and autism spectrum disorder

BackgroundAmbient air pollution and maternal diabetes may affect common biological pathways underlying adverse neurodevelopmental effects. However, joint effects of maternal diabetes and air pollution on autism spectrum disorder (ASD) have not been studied. ObjectiveWe evaluated whether prenatal and early-life air pollution exposure interacts with maternal diabetes status to affect ASD risk. MethodsThis retrospective cohort study included 246,420 singleton children born in Kaiser Permanente Southern California hospitals in 1999–2009. Children were followed from birth until age 5, during which 2471 ASD cases were diagnosed. Ozone (O3), particulate matter < 2.5 μm (PM2.5) and <10 μm in aerodynamic diameter, and nitrogen dioxide measured at regulatory air monitoring stations were interpolated to estimate exposures during preconception and each pregnancy trimester, and first year of life at each child's birth address. Hazard ratios (HRs) for ASD were estimated adjusting for birth year, KPSC service areas, and relevant maternal and child characteristics. For each exposure window, interactions were tested between pollutants and a 4-category maternal diabetes variable (none, GDM ≥ 24 and <24 weeks' gestation, and pre-existing type 2 diabetes). For an exposure window with statistically significant global interaction between pollutant and diabetes (p < 0.05), pollutant-associated HRs were estimated separately for each category of maternal diabetes. ResultsThere were associations of ASD with preconception, first and third trimesters, and first year of life PM2.5, but not with other pollutants. There were, however, interactions of maternal diabetes with first trimester and first year of life O3. Increased ASD risk was associated with first trimester O3 among mothers with GDM < 24 weeks' gestation [adjusted HR 1.50 per 15.7 ppb O3 (95% CI: 1.08–2.09)]. No O3 associations with ASD were observed in other categories of maternal diabetes. ConclusionsGDM onset early in pregnancy may increase children's susceptibility to prenatal O3-associated ASD risk. These novel findings merit further investigation.