OBJECTIVE In studies of associations between genetic factors and outcomes where change in phenotype is of interest, proper modeling of the data, particularly the treatment of baseline trait values, is required to draw valid conclusions. METHODS The authors compared models of blood pressure response to a cold pressor test with and without inclusion of baseline blood pressure as a regressor and...

Gene-environment interactions are of interest in genetic association studies for several reasons. First, the power to detect genetic effects may be substantially decreased if those effects differ according to environmental exposure and if no account is taken of this interaction with environmental exposure in the analysis. Second, such interactions may indicate a phenomenon of genuine biological...

Recent work shows strong evidence of ancestry-based assortative mating in spouse pairs of the older generation of the Framingham Heart Study. Here, we extend this analysis to two studies of human longevity: the Long Life Family Study (LLFS), and the New England Centenarian Study (NECS). In the LLFS, we identified 890 spouse pairs spanning two generations, while in the NECS we used data from 102...