RACIAL AND ETHNIC VARIATIONS IN THE PREVALENCE OF OROFACIAL CLEFTS INCALIFORNIA, 1983-1992

To investigate variations in the prevalence of oral cleft anomalies ac cording to parenatal race and ethnicity and maternal country of birth, the authors analyzed a cohort of 2,221,755 live births and fetal deat hs delivered between 1983 and 1992 to residents of California. A total of 2,329 cleft lip with or without cleft palate (CL +/- P) cases and 1,475 cleft palate alone (CP) cases were identified by the California Birth Defects Monitoring Program, a population-based registry. Compare d to Whites, the prevalence of CL +/- P was lower among African Americ ans (prevalence ratio (PR) = 0.56, 95% confidence interval (CI) = 0.45 -0.69), higher among Native Americans (PR = 1.81, CI = 1.20-2.69), and the same among the Japanese (PR = 1.07, CI = 0.62-1.82) and Chinese ( PR = 0.96, CI = 0.71-1.29). The risk of CL +/- P was slightly lower am ong the offspring of foreign-born Chinese women relative to U.S.-born Chinese women (PR = 0.71, CI = 0.33-1.57), and slightly higher among f oreign-born Filipinos relative to their U.S.-born counterparts (PR = 1 .37, CI = 0.57-3.53), although confidence intervals around these risk estimates were wide owing to sparse data. For CP, lower prevalences we re observed among African Americans (PR = 0.72, CI = 0.58-0.91) and Hi spanics (PR = 0.77, CI = 0.67-0.87) than among Whites. The risk of CP was higher among foreign-born Filipinos compared to U.S.-born Filipino s (PR = 1.52, CI = 0.58-4.33), although the confidence interval around this estimate included unity. These prevalence variations may reflect differences in both environmental and genetic factors affecting cleft ing risk. (C) 1998 Wiley-Liss, Inc.