I respectfully draw your attention to reality and the concept of the chain of circumstances leading to an accident, or the "holes in the swiss cheese lining up" model.
It's never just one thing that results in an accident. Nobody can just point the finger and make a direct connection between LCC and safety. There is unlikely to be a direct relationship for which there is discoverable evidence.
However:
- Pressure on crews.
- pressure on maintenance.
- time pressure.
These may well be factors, but the real question is "Are LCC's under more pressure in this regard than other carriers?"