Are bed bug attacks a sign of dirty living Conditions or living in older homes/building, or is anybody at risk?

Infestations of common bed bugs, Cimex lectularius L., are not directly related to sanitation levels. The cleanest living area can have a very large infestation, and improving sanitation alone will not eliminate an established bed bug population.  Cluttered conditions can offer the bugs a lot of excellent harborages very near their human blood-meal hosts.  Almost anyone is at risk of having an infestation if bed bugs are brought into their home.

Sources: http://www.nbcnews.com