Down syndrome appears to be more common among boys than girls, the study indicates. The condition is also seen more frequently in Hispanic children at birth, though the number of these children appears to level off with that of white children as they age. Black children appear less likely to have Down syndrome.
Who is most affected by Down syndrome?
Women who are 35 years or older when they become pregnant are more likely to have a pregnancy affected by Down syndrome than women who become pregnant at a younger age. However, the majority of babies with Down syndrome are born to mothers less than 35 years old, because there are many more births among younger women.
Why is Down syndrome more common in males?
The two studies suggested an excess of males in the referred population. The decreasing age of mothers of infants with Down syndrome was also evident. Furthermore, more, more males with Down syndrome were born to young couples (age less than 35 years) while elderly couples had an excess of girls.
What race is Down syndrome most common in?
Results: The odds ratio and population attributable risk of Down syndrome due to maternal age of 35 years or older were highest for Mexican Americans, intermediate for African Americans, and lowest for non-Hispanic Whites.
Why is Down syndrome more common in males than in females?
In a huge literature on the epidemiology of Down syndrome, there are two features undoubtedly established, a strong association of free trisomy 21 frequency with advanced maternal age, and male prevalence among patients with Down syndrome due to regular trisomy 21.
Who does Down syndrome affect?
Down syndrome occurs in people of all races and economic levels, though older women have an increased chance of having a child with Down syndrome. A 35 year old woman has about a one in 350 chance of conceiving a child with Down syndrome, and this chance increases gradually to 1 in 100 by age 40.