Sibling similarities in dental caries.

Although dental caries experience clearly follows family line, information on sibling resemblance in the DMFT is surprisingly scarce. The most extensive sibling comparisons involve a limited number of boys and girls analyzed with respect to parental DMFT (RINGELBERG, MATONSKI, and KIMBALL, J Public Health Dent 34: 174180, 1974). In the present study, we have examined DMFT data from the Ten-State Survey of 19681970 (RoWE ET AL, Pediatr 57: 457-461, 1976). These new comparisons involved exactly 16,000 pairs of siblings, 8,674 of them black (American Negro, of largely African ancestry) and 7,326 white (of European derivation) . For each age, DMFT correlations were calculated for boys and girls separately, for blacks and whites separately, and for the three types of sibling correlations (brother-brother, sister-sis4er, and brother-sister) . Tabulations and correlations were arranged according to the midpoint age of the earlier born (older) sibling for each pair. As shown in the table, sibling correlations for the DMFT are systematically positive and statistically significant overall, approximatinig 0.26 for white siblings and 0.40 for black siblings. As might be expected, sibling correlations for the DMFT increase through the earlier