Entitlement to service connection for hypertension is remanded.

Board reasoning

The Board remands to obtain an opinion addressing whether the Veteran's hypertension is aggravated by his service-connected obstructive sleep apnea, including whether obesity is an intercurrent cause. The secondary service connection theory requires addressing both causation and aggravation, per the case law cited in the decision. The examiner must explain why or why not the aggravation is at least as likely as not.