Very Premature Babies Show Raised Risk for Autism, OLDER FATHERS UP The CHANCE OF VERY PREMATURE BIRTH

Very Premature Babies Show Raised Risk for Autism



By Serena Gordon
HealthDay Reporter
Wednesday, April 2, 2008; 12:00 AM

WEDNESDAY, April 2 (HealthDay News) -- Two new studies shed additional light on two different aspects of autism: One tried to pinpoint a risk factor for development of the disorder, while the other looked at the financial toll that having an autistic child takes on a family.

Both studies were expected to be published in the April issue ofPediatricsand were released early in honor of World Autism Day on April 2.

The first looked for early autistic behaviors, though not specifically for a diagnosis of autism, in premature infants who were born at a very low birth weight -- about 3.3 pounds -- and found that several factors associated with these early births were linked to a positive result on an autism screening test.

"The bottom line is that there appears to be a high prevalence of positive screening for autism in survivors of extreme preterm birth and ongoing follow-up is needed to understand if this initial positive screen is transient or persistent," said study author Catherine Limperopoulos, the Canada Research Chair in Brain and Development and an assistant professor in the department of Neurology and Neurosurgery at McGill University in Montreal.

"There is a suggestion [from this study] that preterm infants may be at risk for developing autism, but this is really a preliminary finding that needs to be replicated in a large, prospective study," said Andy Shih, vice president of scientific affairs for Autism Speaks, in New York City.

Limperopoulos and her colleagues studied 91 babies who weighed less than 3 pounds at birth. MRIs were done on these infants around the time they were born. The researchers collected information on the child's health and demographic information, as well as information on their prenatal environment.

At around 22 months, the researchers conducted an autism screening test, called the Modified Checklist for Autism in Toddlers or M-CHAT, as well as other behavior tests. The M-CHAT test is only used to screen children who might have an elevated risk of autism; it is not a definitive diagnostic tool.

Twenty-five percent of these toddlers tested positive on the M-CHAT, suggesting that they had an increased risk of developing autism. Factors that were significantly associated with a positive M-CHAT screen included lower birth weight, lower gestational age, being male, having an abnormal MRI, being ill when delivered, an infection in the mother before birth, or the mother experienced hemorrhaging during labor and delivery.

Limperopoulos said this study wasn't designed to determine causality, but that some type of prenatal or perinatal insult might increase the likelihood of autism.

"I think it's a great study," said Dr. Sara Hamel, a developmental pediatrician in the Child Development Unit at Children's Hospital of Pittsburgh. "A group of infants born preterm and at a low birth weight underwent screening for autism features, and about 25 percent screened positive. That doesn't mean they have it, but that they're at risk. This study really lends weight to the idea that if you screen children around 18 months old, you'll find a number of kids who test positive and need further diagnostic assessment."
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Paternal Age and Preterm Birth.
Brief Reports Epidemiology. 16(2):259-262, March 2005.Zhu, Jin Liang *; Madsen, Kreesten M. *; Vestergaard, Mogens +; Basso, Olga *; Olsen, Jorn *
Abstract: Background: There is growing evidence that advanced paternal age can be a reproductive hazard.
Methods: We studied couples and their first children using nationwide registers in Denmark between 1980 and 1996. We restricted the analysis to mother's age 20-29 years. We estimated odds ratios (ORs) of preterm (<37 weeks gestation) and very preterm birth (<32 weeks) as a function of paternal age using logistic regression to adjust for potential confounding variables.
Results: The risk of preterm birth increased with paternal age, almost entirely resulting from an association for very preterm birth. Compared with fathers age 20-24 years, ORs for very preterm birth were 1.3 (age 25-29), 1.4 (age 35-39), 1.7 (age 40-44), 1.6 (age 45-49), and 2.1 (age 50+) (test for trend: P = 0.01).
Conclusions: Risk of very preterm birth increases among older fathers, perhaps as a result of a paternal placental effect.
(C) 2005 Lippincott Williams & Wilkins, Inc.
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