Maternal age-specific Down syndrome rates by maternal race/ethnicity, Hawaii, 1986-2000.
BACKGROUND
Published maternal age-specific rates for Down syndrome are based mostly on populations of predominately European origin. Down syndrome rates have been reported to vary by race/ethnicity. The objective of this study was to calculate maternal age-specific Down syndrome rates for various racial/ethnic groups and to compare the rates between the racial/ethnic groups.


METHODS
Data were obtained from a population-based birth defects registry and included all Down syndrome cases delivered in Hawaii during 1986-2000 with maternal race/ethnicity of white, Far East Asian, Pacific Islander, or Filipino. Maternal age-specific Down syndrome rates were calculated for each race/ethnicity, and the rates were compared.


RESULTS
The pattern of maternal age-specific Down syndrome rates among Far East Asians and Filipinos was similar to that among whites--Down syndrome rates increased with maternal age, with the increase in rate being most obvious for maternal age groups of 35 years or greater. However, for maternal age of 35 years or greater, the Down syndrome rate was lower for Pacific Islanders than whites, with the difference between the two racial/ethnic groups being significant for maternal age of 40 years or greater (rate ratio 0.13, 95% confidence interval 0.02-0.48).


CONCLUSIONS
All racial/ethnic groups do not appear to demonstrate the same maternal age pattern of Down syndrome rates as whites. This is important because maternal age-specific Down syndrome rates are used to calculate expected Down syndrome rates in a population and to estimate a woman's risk of having an infant with Down syndrome given her age.
Forrester
Mathias B
MB
Hawaii Birth Defects Program, Honolulu, Hawaii 96817-5157, USA.
Merz
Ruth D
RD
D044466:Asian People / Q000208:ethnology; D016001:Confidence Intervals; D004314:Down Syndrome / Q000453:epidemiology* / Q000208:ethnology; D005202:Asia, Eastern / Q000208:ethnology; D005260:Female; D006254:Hawaii / Q000453:epidemiology; D006801:Humans; D007231:Infant, Newborn; D008423:Maternal Age; D010139:Pacific Islands / Q000208:ethnology; D010679:Philippines / Q000208:ethnology; D011247:Pregnancy; D011256:Pregnancy Outcome; D018566:Pregnancy, High-Risk; D012042:Registries / Q000706:statistics & numerical data; D012189:Retrospective Studies; D044465:White People / Q000208:ethnology