Epidemiology of cleft lip and cleft palate in Mississippi.

We present an epidemiologic study of the cases of cleft lip and cleft palate in Mississippi from 1980 through 1989. Cases were stratified by race (white and nonwhite) but not by association with a major malformation. During this period, a total of 457 new patients with cleft lip or cleft palate were identified from a population of approximately 439,354 live births. The incidence of total clefts in live-born infants was 1.36/1,000 for whites and 0.54/1,000 for nonwhites. White boys had a higher incidence of cleft lip and palate than white girls; black boys had an extremely low incidence of cleft lip, whereas black girls showed a higher incidence of cleft palate alone. Examination of the rate of cleft malformations for each county in Mississippi revealed no clearly defined pattern, nor were we able to demonstrate that rates were increased in a major agricultural area of the state, in which use of potentially toxic products is high.