Haw. Code R. § 6-22-7
Permanent incapacity that is caused by or results from the natural deterioration, degeneration, or progression of a non-service connected pre-existing condition is not the natural and proximate result of an accident nor is it the cumulative result of some occupational hazard. The medical board or designated entity shall not consider, and the system shall not grant, disability retirement benefits for a permanent incapacity that is caused by or results from the natural deterioration, degeneration, or progression of a non-service connected pre-existing condition. Whenever there is evidence of a non-service connected pre-existing condition, the applicant shall have the burden of proof, including the burden of producing evidence and the burden of persuasion, of proving that the member's permanent incapacity was not caused by and did not result from the natural deterioration, degeneration, or progression of the non-service connected pre-existing condition. The degree or quantum of proof required shall be by a preponderance of the evidence.
Haw. Code R. § 6-22-7