Consistent Occurrence estimates from the foundationfor determining the resources required for health care and education, as wellas for basic science and public health research. Study of widely extendeddiseases among populations helps us to identify the reasons behind them andalso we can predict public health interventions. The plan of studies toapproximate the incidence of DS must be clearly stated to understand theresults.
Birth incidence or impulsiveand elective abortions can be focused by these studies. The previous would bemore efficient for studying the clinical features of DS, such as heart andgastrointestinal defects, and for estimating healthcare needs, whereas thelatter would be more appropriate for providing information about probableexposures linked with chromosome non disjunction. To approximate the birthincidence of DS in U.S a large study was provided by the report of Canfield etal. 2006. Active –case finding methods were used to obtained data from 11birth inspection systems. All pregnancy outcomes, together with live births,fetal deaths, impulsive and induced abortions and all gestational ages weresuitable.
However, each active inspection system is different in their caseinsertion criteria with respect to pregnancy outcome, gestational age and thecapability to determine parentally diagnosed cases from particular sources.13.65 95% confidence intervals (CI): 13.
22–14.09 per 10,000 live births, or 1/732was the predictable maternal age-adjusted occurrence of DS based on theinspection of 22% of the live births in the U.S. It means that out of 4 millioninfants that born each year in U.S 5,400 have DS.
Canfield et al. furtherinvestigated differences in maternal-age adjusted occurrence rates among thethree major maternal racial/ethnic groups in the U.S.: non-Hispanic white,non-Hispanic black and Hispanic. Compared with non-Hispanic white mothers, theprevalence ratio was 0.77 (95% CI: 0.69–0.
87) for non-Hispanic black mothersand 1.12 (95% CI: 1.03–1.21) for Hispanic mothers. These differences are basedupon important technical issues related to parental records and impulsiveabortions, still birth and live birth. These diseases could also be influencedby the socio economic and educational conditions in these three groups.Khoshnood et al., 2004, 2006; Coory