Epidemiology
The
lifetime prevalence, or the proportion of individuals expected to stutter
at one time in their lives, is about 5%, and overall males are affected
two to five times more often than females. Most stuttering begins in
early childhood and according studies suggest 2.5% of children under
the age of 5 stutter. The sex ratio appears to widen as children grow:
among preschoolers, boys who stutter outnumber girls who stutter about
two to one, or less. but widens to three to one at first grade and five
to one at fifth grade, due to higher recovery rates in girls. Due to
high (approximately 65–75%) rates of early recovery, the overall
prevalence of stuttering is generally considered to be approximately
1%.
Stuttering
occurs in all cultures and races,and at similar rates. A US-based study
indicated that there were no racial or ethnic differences in the incidence
of stuttering in preschool children. Summarizing prevalence studies,
E. Cooper and C. Cooper conclude: “On the basis of the data currently
available, it appears the prevalence of fluency disorders varies among
the cultures of the world, with some indications that the prevalence
of fluency disorders labeled as stuttering is higher among black populations
than white or Asian populations”