Dietary practices of early life and age at death of rats with tumors.

The association between the age at death of rats that develop spontaneous tumors and their early life dietary practices and growth responses was investigated. The data were obtained from outbred male Charles River CD Crl:COBS CD (SD)BR rats maintained for life on a self-selection dietary regimen that permitted them to regulate their protein intake apart from energy intake. A series of multivariable models was derived, after the rats were grouped by tumor type, that accurately accounted for the age of death of the individuals in each class. The models that explain the variance in death age of rats that develop tumors also differed from the combination of factors for rats that do not develop tumors but succumb to other age-related diseases. Although dietary protein and measures of growth are ubiquitous features in these models, no one set of idealized conditions for longevity can be proposed.