More children have disabilities now than a decade ago, and the greatest increase is among children of higher-income families, according to a Children's Hospital of Pittsburgh of UPMC study presented today at the Pediatric Academic Societies (PAS) annual meeting in Washington, DC.

Results of the study, led by Amy Houtrow, M.D., Ph.D., M.P.H., chief, Division of Pediatric Rehabilitation Medicine at Children's Hospital, also showed that while disabilities due to neurodevelopmental and mental health problems have increased sharply, disabilities related to physical health conditions have decreased. This trend was most noteworthy among children under 6 years of age whose rate of neurodevelopmental disabilities nearly doubled during the study, from 19 cases to 36 cases per 1,000 children.

"A century of health care improvements and social changes have altered the face of childhood chronic disease and disability," said Dr. Houtrow, who also is an associate professor of physical medicine and rehabilitation and of pediatrics at the University of Pittsburgh School of Medicine. "Nearly six million kids were considered disabled in 2009 and 2010--almost one million more than in 2001 and 2002."

Dr. Houtrow said that while previous studies have found an increase in the  prevalence of childhood disability, she and the research team wanted to look more closely at the specific conditions and socio-demographic factors associated with disabilities.

The researchers studied data from the National Health Interview Survey conducted by the U.S. Centers for Disease Control and Prevention from 2001 to 2002 and from 2009 to 2010. Participants included more than 102,000 parents of children up to age 17.

The research team assembled a composite of disability indicators to identify disabled children and their associated underlying chronic conditions. Conditions were categorized into three groups: physical, neurodevelopmental/mental health, and other.

The overall rate of disability for children under age 18 increased 16.3 percent between the 2001 to 2002 study period and the 2009 to 2010 study period.

Children living in poverty represented the largest numbers of overall children with disability in both time periods but not the highest growth rates. The largest increase in growth rates of disabilities was seen among children living in households with incomes at or above 300 percent of the federal poverty level--about $66,000 a year for a family of four in 2010.

"We are worried that children living in lower income families may be having problems accessing diagnostic and treatment services," Dr. Houtrow said.

Since the study could not pinpoint why the disability rate is increasing, more research is needed, the author concluded.

Co-investigators were: Kandyce Larson, Ph.D., American Academy of Pediatrics; Paul Newacheck, Dr.P.H., Professor of Pediatrics and Health Policy, University of California San Francisco; Neal Halfon M.D., M.P.H., Professor of Pediatrics, Health Policy and Management, UCLA.