Low Birth Weight and Autism: Examining the Risks
Juan Silva/David Joel
Scientists with the CDC examined 565 children in Atlanta born from 1986 to 1993 with autism and compared them with children from a control group.It turns out that this statement is accurate, but a bit misleading. While the risk of autism does rise for preemies, it actually rises less than the risk for many other disorders. In part, here's what the actual study abstract says:The study found that boy's born at a birth weight of lower than 5.5 pounds had a 2.3-fold increased risk for autism. Girls had a three times or even a higher risk for developing autism.
The scientists also found that low-birth weight and early preterm birth affected groups of children differently, depending on whether they had autism alone or autism and other developmental disabilities.
CDC researchers say this is the first study to look at how gender affects the risk for autism. The findings are published in the June issue of the journal Pediatrics.
The prevalence of autism in low birth weight or preterm children was markedly lower than those of other developmental disabilities. In multivariate analyses, birth weight of <2500 g and preterm birth at <33 weeks' gestation were associated with an approximately twofold increased risk for autism, although the magnitude of risk from these factors varied according to gender (higher in girls) and autism subgroup (higher for autism accompanied by other developmental disabilities). For example, a significant fourfold increased risk was observed in low birth weight girls for autism accompanied by mental retardation, whereas there was no significantly increased risk observed in low birth weight boys for autism alone.Digging a bit deeper, I learned that while low birth weight does, in fact, present a risk factor for autism, the risk is much LESS than that of developing cerebral palsy, mental retardation, hearing loss or vision impairment.
In fact, the most significant finding in this study, it seems, is that the risk of autism, specifically, for low-weight baby girls, is far greater than the risk of autism, specifically, for low-weight boys. So far, no one knows why the risk of autism for preemies is LESS than the risk of other problems - nor why the risk of autism for girl preemies is GREATER than that for boy preemies.
A related article in US News and World Reports cites the researchers:
"This gives us more clues [about autism], which we desperately need, but it's not anything clinicians can use right away," said Dr. Cindy Molloy, an autism researcher and clinical assistant professor of pediatrics at the Center for Epidemiology and Biostatistics at Cincinnati Children's Hospital.Was your child with autism premature or low-birth-weight? What are the issues you've seen?The results do reinforce the importance of monitoring children who are born underweight or early for behavioral problems so they can be treated, said study author Diana Schendel, lead health scientist at the CDC's National Center on Birth Defects and Developmental Disabilities.
Comments
It is hard for me to accept some of these studies done on such a small number/segment of the population. According to the doctors both of my boys were premature. My oldest, early by one month (possible miscalculation) my youngest by two months (not a miscalculation). My oldest is autistic and weighed 8.9, my youngest is not and weighed 5.5 (I grow them big, what can I say). In another life, I used to be an analyst. The numbers can say just about anything because they “wash” or “scrub” them. It is difficult to believe any study nowadays; at least for me.