Down syndrome increases among U.S. children

Older average maternal age may have contributed to a 31.1% increase in the number of babies born with Down syndrome from 1979 to 2003, researchers believe.

During this time period, the prevalence of Down syndrome at birth increased from 9.0% to 11.8% per 10,000 live births, data pooled from 10 U.S. regions indicated, with prevalence rates five times higher among babies born to mothers who were aged 35 or older compared with younger mothers (38.6 per 10,000 vs. 7.8 per 10,000).

Increased Down syndrome prevalence at birth coupled with an increased median age among individuals with the birth defect (25 years in 1983 vs. 49 in 1997), may have important implications for resource allocation as these children age, according to the researchers.

“Determination of whether health services are meeting the needs of an increasing number of aging individuals with Down syndrome to ensure a healthy life across the life span is likely to require more extensive data linkages of health databases on individuals with Down syndrome,” the researchers wrote. They added that development and maintenance of long-term longitudinal registries will be integral to these efforts.

After adjusting for age, race/ethnicity and gender the researchers determined the following:

Although prevalence increased with time in each age group, it decreased with age within birth cohorts.
Prevalence was significantly higher among boys compared with girls.
Prevalence was significantly lower among non-Hispanic blacks and decreased more rapidly with age among Hispanics compared with non-Hispanic whites.

Decreasing trends in Down syndrome prevalence as Hispanic children age may be due to lower survival rates after birth, the researchers suggested.

“Because Hispanic immigrant women tend to have higher rates of fertility, late entry to prenatal care and lower levels of insurance coverage, it is important to conduct more research to elucidate the extent to which these factors might be associated with the observed trends in prevalence and survival in states with rapid Hispanic population growth,” the researchers wrote.

This large, population-based study is the first of its kind, accounting for 29% of all Down syndrome births in 2002 and encompassing data from birth defect registries from Arkansas, California, Colorado, Georgia, Iowa, North Carolina, New York, Oklahoma, Texas and Utah.

Shin M. Pediatrics. 2009;124:1565-1571.

This evidence of increasing prevalence of children with Down syndrome should alert pediatricians to the need for development of proper medical home settings for these children with chronic medical and developmental conditions. Those affected and their families need and deserve coordinated care, with special focus from both their primary care provider and their subspecialists, in order to assure good health and optimal long-term well-being. As survival increases, pediatricians can be expected to play an important role in these children's lives.

– Paul H. Lipkin, M.D.

Kennedy Krieger Institute

Johns Hopkins University School of Medicine