BODY-MASS INDEX AND FAMILY HISTORIES IN TYPE-II DIABETIC PROPOSITI AND PRELIMINARY-OBSERVATIONS ON THE TRANSMISSION OF DIABETES IN POLYGAMOUS FAMILIES

We studied family histories of diabetes mellitus in the first-degree r elatives of 356 type II diabetic propositi in whose families monogamy is practiced. Positive family histories were noted in 32% of the propo siti: parental 20%, sibling 14%, and offspring 0.6%. In 11 pedigrees w ith conjugal diabetic parents, 33% (18/55) of their offspring were dia betic. Paternal influence was significantly higher than maternal influ ence (43 of 62 vs. 19 of 62, Z=2.86, p <0.01). The presence or absence of sibling history did not depend on the body mass index in the propo siti. We also studied pedigrees of 10 propositi in whose paternal fami lies polygamy is practiced. In these families also a trend toward grea ter paternal influence was noted. We conclude that (1) a family histor y of diabetes is present in one-third of diabetic propositi, (2) pater nal influence is stronger than maternal influence in the transmission of diabetes, (3) sibling history for diabetes has no relation to the b ody mass index of the propositi, (4) prevalence of diabetes is higher in the offspring of conjugal diabetic parents, and (5) studies in poly gamous families are a new approach that may help to quantify the genet ic load transmitted from a parent when there is heterogeneity in the s pouses.