I would like to estimate the association between exposure to an environmental contaminant and all-cause mortality. Unfortunately the dataset I can get access to is incomplete - exposure data are only available for approximately 5% of the entire cohort, and these 5% are reasonably random (essentially based on accessibility in a freezer - but not linked to collection date etc).
In an ideal world, I would like to conduct a survival analysis as I could do with other data - but I don't know whether this is really appropriate. Would it be more appropriate to use logistic regression here?
Edit: they are reasonable random as samples were treated after collection and processed in a way that was not linked to collection date/site.