Risk and protective factors for urolithiasis. What do they mean?

The occurrence of urolithiasis in companion animals is associated with several risk and protective factors. Case control studies are commonly designed to study the relationship between naturally occurring urolithiasis and risk factors. However, case control studies are subject to limitations, biases, and confounding variables; they do not prove cause and effect relationships. Likewise, just because two events occur in consecutive order does not prove a cause and effect relationship.