Citation Nr: 21010672 Decision Date: 02/25/21 Archive Date: 02/25/21 DOCKET NO. 10-41 503 DATE: February 25, 2021 REMANDED Entitlement to service connection for obstructive sleep apnea (OSA), to include as secondary to posttraumatic stress disorder (PTSD) and/or diabetes mellitus, type II, is remanded. REASONS FOR REMAND The Veteran served on active duty in the United States Army from September 1958 until his honorable retirement in June 1981. This case comes before the Board on appeal from a November 2009 rating decision. In a February 2017 decision, the Board denied the Veteran’s claim for service connection for OSA. The Veteran subsequently appealed the Board’s decision to the United States Court of Appeals for Veterans Claims (Court). In May 2018, in pertinent part, the Court set aside the Board’s February 2017 decision to deny service connection for OSA and remanded the matter for further development, if necessary, and readjudication consistent with its Memorandum Decision. In April 2019, the Board remanded the case to the RO for further development consistent with the Court’s decision. Most recently, in September 2020, the Board again remanded the matter for further development. As part of the Board’s September 2020 remand directives, the RO was to obtain an addendum opinion regarding the etiology of the Veteran’s OSA. Specifically, the examiner was to provide an opinion on whether “the Veteran’s obstructive sleep apnea had its onset in, or is otherwise related to, active service; including but not limited to secondary to a service-connected disability (including aggravation) and/or due to combat experiences in service.” The Board further directed the examiner to specifically address the theory that the Veteran’s obstructive sleep apnea was aggravated by his service-connected type II diabetes mellitus and the Veteran’s assertion that VA doctor linked his obstructive sleep apnea to combat experiences in service. The requested opinion was obtained in December 2020. The examiner opined that the Veteran’s OSA was less likely than not caused by his diabetes mellitus or combat experiences because there was no objective evidence of the OSA during service, no objective evidence of a direct or causal relationship between the diabetes or combat experience and development of OSA. The examiner also opined the Veteran’s OSA was less likely than not aggravated by his diabetes for the same reasons. Finally, the examiner indicated the Veteran’s obesity was the primary risk factor for development of OSA. In rendering the opinion that obesity was the primary risk factor for development of OSA, the December 2020 examiner did not address whether the Veteran's obesity was caused by his service-connected disabilities. See Walsh v. Wilkie, 32 Vet. App. 300, 306-07 (2020) (holding that obesity as an “intermediate step” in a causal chain for service connection can be established on either a causal or aggravation basis). Accordingly, a remand is necessary to obtain an addendum opinion regarding whether obesity has served as an intermediate step between the Veteran’s service-connected disabilities and his claimed OSA. Accordingly, the matter is REMANDED for the following actions: 1. Obtain an addendum opinion from an appropriate clinician regarding the etiology of the Veteran’s OSA. The entire claims file must be made available to and be reviewed by the examiner, including a copy of this REMAND order. If the examiner decides an examination is necessary, then one shall be provided. The examiner must opine whether the Veteran’s obesity was an intermediate step between his current OSA and his service-connected diabetes and/or PTSD. In so doing, the examiner should state whether it is at least as likely as not (50 percent probability or greater) the Veteran’s diabetes and/or PTSD caused the Veteran to become obese or aggravated his obesity. If so, the examiner should provide an opinion as to whether the obesity, or the aggravation of obesity, as a result of either the service-connected diabetes or PTSD was a substantial factor in causing OSA and whether OSA would not have occurred but for obesity caused or aggravated by the service-connected diabetes and/or PTSD. A clear and detailed rationale for the opinion(s), including a discussion of the facts and medical principles involved, should be provided as it will be of considerable assistance to the Board. If a requested opinion cannot be provided without resorting to speculation, the examiner should so state and explain why an opinion cannot be provided without resorting to speculation. In so doing, the medical professional shall explain whether the inability to provide a more definitive opinion is the result of a need for additional information, or that he or she has exhausted the limits of current medical knowledge in providing an answer to the particular question(s). (CONTINUED ON NEXT PAGE)   2. If upon completion of the above action the claim remains denied, the matter must be returned to the Board after compliance with appellate procedures. K. L. Wallin Acting Veterans Law Judge Board of Veterans’ Appeals Attorney for the Board J. F. Sawka, Associate Counsel The Board’s decision in this case is binding only with respect to the instant matter decided. This decision is not precedential and does not establish VA policies or interpretations of general applicability. 38 C.F.R. § 20.1303.