Infant health and neurobehavioral outcomes in childhood

In recent years, the prevalence of mental disabilities amongst the U.S. children has been on the rise. This imposes a large economic burden on the families as well as on the government which provide SSI and SSDI benefits for them. Existing literature indicates that the improved survival of very low birth weight babies contributed to the trend, but the research design of most studies fails to control for genetic as well as family backgrounds. Using a U.S. sample of 2000 siblings from the 1997-2007 PSID-CDS, we investigate the effects of low birth weight on neurobehavioral outcomes, as measured by the Behavior Problems Index and ever-diagnosed developmental disabilities in children. We use panel data methods with mother fixed-effects that allow for correlated unobserved factors including inheritance and family background affecting low birth weight. Strong negative effects of low birth weight on ADHD, developmental delay, and mental retardation are estimated. Low birth weight (less than 2,500 gram) increases the probability of having ADHD over the childhood by 1.5%, Developmental Delay by 10.6%, and Mental Retardation by 2.8%. Very low birth weight (less than 1,500 gram) increases the risk of ADHD by 16.8%, Developmental Delay by 26.2%, and Mental Retardation by 7.9%. The estimated magnitude of birth weight effects are significantly larger than those reported in previous studies. Our results suggest that public policy interventions like WIC that improve birth outcomes will have substantial long-term benefits in terms of improved neurobehavioral outcomes in the childhood and beyond.