The prevalence of Down syndrome at birth rose by more than thirty percent in 10 U.S. regions from 1979 to 2003, according to new work by researchers at the Centers for Disease Control and Prevention.
The study, published in the journal Pediatrics, found that nearly 12 babies per 10,000 born in 2003 had Down syndrome, as compared with about 9 babies in every 10,000 born in 1979. It found that Down syndrome was more common among Hispanics and whites than among African Americans, and was more often found in boys than in girls.
Dr. Adolfo Correa of the CDC’s National Center on Birth Defects, one of the study’s authors, told Reuters that the increase in prevalence is probably caused by the increasing trend toward later child-bearing. Women over 35 are five times more likely than younger women to have children with Down syndrome, he said.
Correa said the research couldn’t determine what effect widespread prenatal screening and selective abortion have had on the incidence of Down syndrome.
Because the incidence of Down syndrome at birth is increasing and medical advances are lengthening the life expectancies of people with the disorder, the researchers said, the number of people with Down syndrome is likely to increase over time.
The scientists concluded that more research is necessary to determine whether health services are meeting the needs of people with Down syndrome across the lifespan, and suggested the development of registries to track the development and health needs of people with Down syndrome throughout their lives.
The ten regions studied were Georgia (5 metropolitan Atlanta counties), California (11 counties), Colorado, Iowa, North Carolina, Arkansas, New York (excluding New York City), Oklahoma, Texas and Utah. Arkansas reported the smallest prevalence of Down syndrome at birth, at 9.7 per 10,000, while Utah reported the highest, at 13.7.
In Utah, Down syndrome is more prevalent — Salt Lake Tribune A Utah expert on birth defects says the state’s higher incidence of Down syndrome births is likely caused by the ages and attitudes of mothers. Utah women are having children into their late 30s and 40s, he said, and are less likely to have abortions if the condition is diagnosed in utero.
The higher prevalence is “not because there is something wrong with Utah,” he said in an e-mail, “but is basically a function of family choices.”
(Graphic from the Salt Lake Tribune)