The analysis of intra-group correlations between LS and BW at representative intervals yields no consistent support for the hypothesis that lower BW is associated with longer LS. Indeed, among male Wistar rats and C57BL/6J and A/J mice followed since weaning on AL diets, the data suggested that relatively higher BW across the adult LS was generally associated with longer life. Even when the diet was restricted by EOD or RES regimens, this pattern of positive correlations between LS and BW persisted for the C57BL/6J and A/J strains when relative ages were analyzed. However, when BW at absolute...

The human race has enormous he terogenei ty, founded on genetic and environmental sources. Variability, therefore, is a vital dimension in any consideration of human risk assessment. In the estimation of risks, current methods of extrapolation based upon converting the response of a median man are inadequate, as they ignore phenotypic variation and there- fore, susceptible subgroups. There is a growing literature defining the extent of human variation in normal populations; thus, the normal young adult population may have 10-20% known hyperreactors. How far can we ignore human variability in...