330 The Association Between Preterm Birth and Autism Could be Explained by Maternal and Neonatal Morbidity

Department of Medical Epidemiology and Biostatistics, Karolinska Institute, PO Box 281, SE-171 77 Stockholm, Sweden.
PEDIATRICS (Impact Factor: 5.47). 10/2009; 124(5):e817-25. DOI: 10.1542/peds.2008-3582
Source: PubMed


We examined whether an association between preterm birth and risk of autistic disorders could be explained by pregnancy complications or neonatal morbidity.
This Swedish, population-based, case-control study included 1216 case subjects with autistic disorders who were born between 1987 and 2002 and 6080 control subjects who were matched with respect to gender, birth year, and birth hospital. We assessed associations between gestational age and autistic disorders and adjusted for maternal, birth, and neonatal characteristics. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).
Compared with infants born at term, the unadjusted ORs for autistic disorders among very and moderately preterm infants were 2.05 [95% CI: 1.26-3.34] and 1.55 [95% CI: 1.22-1.96], respectively. When we controlled for maternal, pregnancy, and birth characteristics, ORs were reduced to 1.48 [95% CI: 0.77-2.84] and 1.33 [95% CI: 0.98-1.81], respectively. When we also controlled for neonatal complications, ORs were 0.98 [95% CI: 0.45-2.16] and 1.25 [95% CI: 0.90-1.75], respectively. Reductions in risks of autistic disorders related to preterm birth were primarily attributable to preeclampsia, small-for-gestational age birth, congenital malformations, low Apgar scores at 5 minutes, and intracranial bleeding, cerebral edema, or seizures in the neonatal period. Neonatal hypoglycemia, respiratory distress, and neonatal jaundice were associated with increased risk of autistic disorders for term but not preterm infants.
The increased risk of autistic disorders related to preterm birth is mediated primarily by prenatal and neonatal complications that occur more commonly among preterm infants.

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    • "However, epidemiological findings have not consistently found evidence of increased ASD risk with infection. For example, a California study of 407 ASD cases reported that hospitalization with infection was associated with increased risk (Zerbo et al., 2013), while a Swedish study of 1216 ASD cases found no such evidence (Buchmayer et al., 2009), In order to build the evidence base concerning prenatal infection and ASD risk, additional epidemiological studies are necessary. "
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    Brain Behavior and Immunity 09/2014; 44. DOI:10.1016/j.bbi.2014.09.001 · 5.89 Impact Factor
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    • "Overall (I-squared = 15.7%, p = 0.302) Diabetes before and during pregnancy Brimacombe et al Diabetes during pregnancy Hultman et al Leonard et al Croen et al Piven et al Elhameed et al Subtotal (I-squared = 0.0%, p = 0.721) Subtotal (I-squared = 43.0%, p = 0.154) Krakowiak et al Juul-Dam et al Buchmayer et al Author 2007 2002 2006 2005 1993 2011 2012 2001 2009 Year 1.73 (1.24, 2.42) 1.61 (0.82, 3.17) 1.20 (0.28, 5.23) 2.95 (1.30, 6.71) 2.60 (0.83, 8.17) 3.08 (0.12, 78.48) 6.33 (0.24, 166.42) 2.23 (1.38, 3.60) 1.47 (0.87, 2.47) 1.52 (0.82, 2.82) 3.28 (1.32, 8.16) 0.90 (0.49, 1.66) RR (95% CI) 1 .1 10 Fig. 4 "
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    ABSTRACT: We performed a systematic literature search regarding maternal diabetes before and during pregnancy and the risk of autism spectrum disorders (ASD) in the offspring. Of the 178 potentially relevant articles, 12 articles including three cohort studies and nine case-control studies were included in the meta-analysis. Both the meta-analyses of cohort studies and case-control studies showed significant associations. The pooled relative risk and 95 % confidence interval (CI) among cohort studies was 1.48 (1.25-1.75, p < 0.001). For case-control studies, the pooled odds ratio and 95 % CI was 1.72 (1.24-2.41, p = 0.001). No indication of significant heterogeneity across studies or publication bias was observed. In conclusion, maternal diabetes was significantly associated with a greater risk of ASD in the offspring.
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    • "These findings point to the presence of non-heritable risk factors for autism. This observation has also been supported by the studies, that revealed the association between autism and prenatal, perinatal and neonatal conditions, like advanced parental age, low birth weight, low Apgar score, low weight for gestational age, gestational age at birth less than 37 weeks, cesarean section, and congenital malformations [4] [5] [6] [7] [8]. Some of them indicate the role of vaccines as risk factors for autism and others for pervasive developmental disorders. "
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