I have been using my 7D for 4 years now and never really noticed luminance noise but a couple of recent batches off photos with low ISO and nice bright sunlight conditions are yielding more noise in the images than I am used to. My question is, can a camera's noise performance degrade with age?
Definitely sensor can degrade with the age of the camera, but also with the number of shots you made.
Professional equipment has normally a kind of build in shot counter and one of measures how old or how much the camera is used is this one. And exactly the number of exposures somewhat damages sensor.
But I am not sure in what range of shots is your camera. The comments left to your question are very useful.
Finally - you can test if your sensor is damaged or not: How can I easily tell if a sensor or lens is damaged?