opc,

All cause mortality is exactly what it says - death from any cause during the study interval. Could be cancer, heart attack, trauma, natural causes - anything.

Let's say Exubera does in fact increase primary lung cancer mortality (the fact is that it appears to increase it only minimally). But by being on the inhaled Exubera, the patients actually may be less likely to die of complications of diabetes.

All this study is saying is that whatever factors are in play, they're cancelling each other out so that the risk of dying while on Exubera overall is no higher that the comparitor group.