There are no longer enough child safety seats to accommodate the increasing number of obese American children, researchers report.
Reversing the trend of childhood obesity could take years, they say, so the quicker solution is better-designed safety seats.
"The childhood obesity trend is on the rise and has been for decades," said lead researcher Lara Trifiletti, an assistant professor of pediatrics at the Ohio State University and the Center for Injury Research and Policy, part of the Columbus Children's Research Institute at Columbus Children's Hospital.
"It's going to get worse before it gets better, and we can't really wait for reductions in childhood obesity to fix the problems because it's an immediate safety issue. We definitely need to see seats that have been designed and tested and approved at higher weights," Trifiletti said.
The findings appear in the April issue of Pediatrics.
"Children who are either large or obese do have a problem finding the appropriate seat," said Dr. Maja Djordjevic, director of pediatrics at Nyack Hospital in Nyack, N.Y. "It's also a problem with the developmental level because you can't put them in a booster seat because they don't have a five-point harness."
Djordjevic speaks from experience: Her son is tall, though not obese, and she has had trouble finding the appropriate seat for him.
According to information presented in the study, over the past three decades, the rates of obesity have doubled for children aged 2 to 5 and for adolescents aged 12 to 19. The rates have tripled for children 6 to 11 years of age.
One estimate posits that as many as 10 percent of children aged 2 to 5 are obese. And rates may be higher in low-income populations.
While the health consequences of obesity have been amply chronicled, there has been little research into the safety implications.
The authors of this study decided to focus on child seats because technicians at the Children's Safety Center (CSC) were noting the number of obese children who exceeded the upper weight limit for car seats. CSC loans seats and also sells them at low cost to low-income, urban families.
Child seats are required by law. Motor vehicle crashes account for 23 percent of deaths from injury among infants and 30 percent among preschool-aged children. Each year in the United States, more than 1.5 million children are in motor vehicle crashes. Car seats have been shown to substantially reduce the risk of dying.
For this study, Trifiletti and her colleagues assessed child safety seats using the National Highway Traffic Safety Administration's 2005 Child Safety Seat Ease of Use Ratings. They estimated the numbers of children exceeding the maximum weight for these seats using national data from 1999 and 2000.
As it turned out, about 283,000 children aged 1 to 6 would have difficulty finding a safe child safety seat because of their combined age and weight. Most of the "problem kids" (182,661) were 3 years old and weighed more than 40 pounds. For this age group, there are only four child safety seat types available, which cost between $240 and $270 (in contrast, some seats for normal-weight children sell for as low as $14).
More than 8,500 children 2 years of age and almost 92,000 children 4 to 6 years of age would also have a difficult -- if not impossible -- time finding appropriate car seats.
The issue is an especially critical one for low-income families who are not only more at risk for injuries, but also are more likely to be overweight.
"If a child is large or obese, the seats are very expensive, which hits hardest the lower socioeconomic groups and minorities," Djordjevic said. "It's just out of their reach. The parents may also get into trouble legally, as states have child occupant protection laws. If the child is not restrained properly, there's a fine."
The researchers believe their numbers are, if anything, an underestimate, since the data was not completely up to date.
Manufacturers are already reacting to the problem, however.
"Since we did this study, there have been at least two seats that have come on the market that would accommodate these age groups, and they are actually less expensive," Trifiletti said.
For more on child car safety, head to the U.S. National Highway Traffic Safety Administration.