§3.310. Disabilities that are proximately due to, or aggravated by, service-connected disease or injury. — Inbound Citations

(c) For claims for secondary service connection received by VA after June 9, 1998, a disability that is proximately due to or the result of an injury or disease previously service-connected on the basis that it is attributable to the veteran's use of tobacco products during service will not be service-connected under § 3.310(a).

Intellectual disability (intellectual developmental disorder) and personality disorders are not diseases or injuries for compensation purposes, and, except as provided in § 3.310(a) of this chapter, disability resulting from them may not be service-connected. However, disability resulting from a mental disorder that is superimposed upon intellectual disability (intellectual developmental disorder) or a personality disorder may be service-connected.

(3) Secondary service connection is established for ischemic heart disease or other cardiovascular disease under § 3.310(b).