What is "prevalent undiagnosed disease"?

[NewHopeR]

Context:

The inverse association was restricted to current and formersmokers and was stronger after adjustment for smoking. Among smokers, theinverse association persisted even after finely stratifying on smoking status,time since quitting smoking, and number of cigarettes smoked per day.Sensitivity analyses did not support the possibility that the inverseassociation was due to prevalent undiagnosed disease.

[SoothingDave]

Which word's definition is troubling you?

[NewHopeR]

Which word's definition is troubling you?

The logic is troubling.
If a disease is undiagnosed, how can you know whether it is prevalent or not?

[SoothingDave]

They don't have to logically conflict. Disease can exist without the symptoms being overwhelming or so severe that they cause a person to seek out medical help.

Take diabetes, for instance. Obesity can cause diabetes to develop. There are a lot of overweight Americans. There is no doubt that there are a lot of undiagnosed Americans who have diabetes.