Age may not be considered as a factor in evaluating service-connected disability; and unemployability, in service-connected claims, associated with advancing age or intercurrent disability, may not be used as a basis for a total disability rating. Age, as such, is a factor only in evaluations of disability not resulting from service, i.e., for the purposes of pension. [29 FR 6718, May 22, 1964, as amended at 43 FR 45349, Oct. 2, 1978]