Risk or selection effect?

Kaiser Fung at Numbers Rule Your World, on the European E. coli outbreak:

One other point: the level of risk is not the same for everyone. Most E-coli fatalities in past outbreaks have been elderly women or children with already compromised immune systems. In this case, 13 of 19 deaths were adult women, a little unusual but still a concentration of risk among a subset of the population. (link)

Just like a lot of situations, the "average" risk is not useful here. It's important to know if you are in the high-risk subgroup or not.

Are women more susceptible to the infection, or do they just eat more sprouts? My anecdotal experience (also, admittedly, on a different continent) suggests the latter.