The simple answer is: not in the near-infrared region.
In the low energy, near-infrared wavelength range used by NIR-Online process analyzers only mechanical aging of optical fibers owing to e.g. bending needs to be taken into account. Overall life time is in the order of decades in case of proper treatment. Additionally, any negative effects on the optical fiber are included in the white reference measurement as well as the sample measurement and therefore cancel when determining I/I0 (see FAQ 1).
Tremendous aging of glass fiber bundles (signal damping within a fiber) is commonly observed for high frequency irradiation such as ultra-violet (UV) or X-ray leading to glass defects. These lower the degree of total reflection, the fundamental operating principle of an optical fiber. Above described irradiation induced glass defects do not occur in the near-infrared spectral range for mere reasons of physics.