title: Maternal intake of supplemental iron and risk of autism spectrum disorder.
abstract: Iron deficiency affects 40%-50% of pregnancies. Iron is critical for early neurodevelopmental processes that are dysregulated in autism spectrum disorder (ASD). We examined maternal iron intake in relation to ASD risk in California-born children enrolled in a population-based case-control study (the Childhood Autism Risks from Genetics and the Environment (CHARGE) Study) from 2003 to 2009 with a diagnosis of ASD (n = 520) or typical development (n = 346) that was clinically confirmed using standardized assessments. Mean maternal daily iron intake was quantified on the basis of frequency, dose, and brands of supplements and cereals consumed each month from 3 months before pregnancy through the end of pregnancy and during breastfeeding (the index period), as reported in parental interviews. Mothers of cases were less likely to report taking iron-specific supplements during the index period (adjusted odds ratio = 0.63, 95% confidence interval: 0.44, 0.91), and they had a lower mean daily iron intake (51.7 (standard deviation, 34.0) mg/day) than mothers of controls (57.1 (standard deviation, 36.6) mg/day; P = 0.03). The highest quintile of iron intake during the index period was associated with reduced ASD risk compared with the lowest (adjusted odds ratio = 0.49, 95% confidence interval: 0.29, 0.82), especially during breastfeeding. Low iron intake significantly interacted with advanced maternal age and metabolic conditions; combined exposures were associated with a 5-fold increased ASD risk. Further studies of this link between maternal supplemental iron and ASD are needed to inform ASD prevention strategies.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Schmidt
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Tancredi
authors.forename: Paula
authors.initials: P
authors.lastname: Krakowiak
authors.forename: Robin L
authors.initials: RL
authors.lastname: Hansen
authors.forename: Sally
authors.initials: S
authors.lastname: Ozonoff
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000517:prevention & control*; D002675:Child, Preschool; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D007501:Iron / Q000008:administration & dosage*; D016015:Logistic Models; D008297:Male; D009035:Mothers; D016017:Odds Ratio; D011247:Pregnancy
chemical_list: D007501:Iron
keywords: autism; case-control studies; child development; dietary supplements; iron; pregnancy; primary prevention; risk factors