We examined trends in autism spectrum disorder diagnoses by age 36 months (early diagnoses) and identified characteristics associated with early diagnoses.
Massachusetts birth certificate and early-intervention program data were linked to identify infants born between 2001 and 2005 who were enrolled in early intervention and receiving autism-related services before age 36 months (through December 31, 2008). Trends in early autism spectrum disorders were examined using Cochran-Armitage trend tests. χ2 Statistics were used to compare distributions of selected characteristics for children with and without autism spectrum disorders. Multivariate logistic regression analyses were conducted to identify independent predictors of early diagnoses.
A total of 3013 children (77.5 per 10 000 study population births) were enrolled in early intervention for autism spectrum disorder by age 36 months. Autism spectrum disorder incidence increased from 56 per 10 000 infants among the 2001 birth cohort to 93 per 10 000 infants in 2005. Infants of mothers younger than 24 years of age, whose primary language was not English or who were foreign-born had lower odds of an early autism spectrum disorder diagnosis. Maternal age older than 30 years was associated with increased odds of an early autism spectrum disorder diagnosis. Odds of early autism spectrum disorders were 4.5 (95% confidence interval: 4.1–5.0) times higher for boys than girls.
Early autism spectrum disorder diagnoses are increasing in Massachusetts, reflecting the national trend observed among older children. Linkage of early-intervention program data with population-based vital statistics is valuable for monitoring autism spectrum disorder trends and planning developmental and educational service needs.
Thank you for the interesting article by Manning et al., which indicates that autism continues to increase [1]. The reason for this increase must be sought.
Autism is a neurological disorder. The brain and all factors that can affect brain development should be of greatest importance in epidemiological research. In addition to the selected characteristics reported and discussed by Manning et al., would it be possible to provide information on perinatal factors that might interfere with brain development? In particular: data on medicines taken during pregnancy, prenatal use of alcohol and other drugs, cesarean section and other interventions at birth, time to first breath, Apgar scores, resuscitation, respiratory depression, bilirubin levels, and neonatal interventions such as antibiotics, vitamin K, and hepatitis B vaccination.
Developmental language disorder is the most serious handicap for children with autism. For decades I have been trying to bring attention to seminal research evidence that has too long been ignored [2].
Ranck and Windle (1959) found primary damage of nuclei in the auditory pathway following asphyxiation of monkeys at birth [3]. Lucey et al. (1964) reported that the blood-brain barrier was compromised by asphyxia at birth in nuclei of the auditory pathway and the basal ganglia, and that bilirubin staining of these nuclei only occurred in monkeys subjected to asphyxia [4]. Faro and Windle (1969) observed that brain maturation did not proceed normally in monkeys asphyxiated at birth [5].
Kety (1962) described research that revealed the highest rate of blood flow in nuclei of the auditory pathway [6]. These nuclei then are vulnerable to any abnormal metabolite or substance in the circulation. No medications or other substances should be used during pregnancy or the early neonatal period. Every effort should be made to avoid any lapse in oxygen delivery during transition from placental to pulmonary respiration. Could increasing collections of umbilical cord blood interfere with respiratory transition, thus leaving many newborn infants with impairments of the auditory system?
[1] Manning SE, Davin CA, Barfield WD, Kotelchuck M, Clements K, Diop H, Osbahr T, Smith LA. Early Diagnoses of Autism Spectrum Disorders in Massachusetts Birth Cohorts, 2001-2005. Pediatrics. 2011 Epub May 16.
[2] Simon N. Echolalic speech in childhood autism. Consideration of possible underlying loci of brain damage. Arch Gen Psychiatry. 1975 Nov;32(11):1439-46.
[3] Ranck JB, Windle WF. Brain damage in the monkey, Macaca mulatta, by asphyxia neonatorum. Exp Neurol. 1959 Jun;1(2):130-54.
[4] Lucey JF, Hibbard E, Behrman RE, Esquival FO, Windle WF. Kernicterus in asphyxiated newborn monkeys. Exp Neurol 1964 Jan; 9(1):43- 58.
[5] Faro MD, Windle WF. Transneuronal degeneration in brains of monkeys asphyxiated at birth. Exp Neurol. 1969 May;24(1):38-53.
[6] Kety SS. Regional neurochemistry and its application to brain function. Bull N Y Acad Med. 1962 Dec;38:799-812. Online free at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1804882/?tool=pubmed
Conflict of Interest:
Mother of a son with autism