To examine the time-dependent effects of exposure histories on disease, we
estimate a weight function within a generalized linear model. The shape of
the weight function, which is modeled as a cubic B-spline, gives informatio
n about the impact of exposure increments at different times on disease ris
k. The method is evaluated in a simulation study and is applied to data on
smoking histories and lung cancer from a recent case-control study in Germa
ny.