Citation Nr: 21028793 Decision Date: 05/12/21 Archive Date: 05/12/21 DOCKET NO. 12-26 402 DATE: May 12, 2021 ORDER Entitlement to service connection for benign hypertrophy of the prostate (claimed as enlarged prostate) is denied. Entitlement to service connection for hypertension is denied. Entitlement to service connection for sleep apnea is denied. FINDINGS OF FACT 1. The most probative evidence of record does not show benign hypertrophy of the prostate (claimed as enlarged prostate) to be etiologically related to a disease, injury, or event in service or to a service-connected disability. 2. The most probative evidence of record does not show hypertension to be etiologically related to a disease, injury, or event in service or to a service-connected disability. 3. The most probative evidence of record does not show sleep apnea to be etiologically related to a disease, injury, or event in service or to a service-connected disability. CONCLUSIONS OF LAW 1. The criteria for entitlement to service connection for benign hypertrophy of the prostate (claimed as enlarged prostate) have not been satisfied. See 38 U.S.C. §§ 1110, 1116, 5103, 5103A, 5107 (West 2014); 38 C.F.R. §§ 3.102, 3.159, 3.304, 3.307, 3.309, 3.310 (2020). 2. The criteria for entitlement to service connection for hypertension have not been satisfied. See 38 U.S.C. §§ 1110, 1116, 5103, 5103A, 5107 (West 2014); 38 C.F.R. §§ 3.102, 3.159, 3.304, 3.307, 3.309, 3.310 (2020). 3. The criteria for entitlement to service connection for sleep apnea have not been satisfied. See 38 U.S.C. §§ 1110, 1116, 5103, 5103A, 5107 (2012); 38 C.F.R. §§ 3.102, 3.159, 3.304, 3.307, 3.309, 3.310 (2020). REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran served on active duty from November 1967 to June 1969. In July 2018, the Board denied service connection for benign hypertrophy of the prostate (claimed as enlarged prostate) and remanded claims for service connection for sleep apnea and hypertension. The Veteran appealed the denial of his claim for service connection for benign hypertrophy of the prostate (claimed as enlarged prostate) to the United States Court of Appeals for Veterans Claims (Court). In a July 2019 Joint Motion for Partial Remand (JMPR), the Veteran and the Secretary of Veterans Affairs requested to vacate the Board's denial of this claim and to remand the issue for readjudication. The Court granted the JMPR and remanded the matter for action consistent with the JMPR's terms. In December 2019 and October 2020, all issues addressed in the July 2018 determination were remanded by the Board for further development. The issues have now been returned to the Board. The Board must assess the credibility and weight of all evidence, including the medical evidence, to determine its probative value, accounting for evidence which it finds to be persuasive or unpersuasive, and providing reasons for rejecting any evidence favorable to the claimant. Equal weight is not accorded to each piece of evidence contained in the record; every item of evidence does not have the same probative value. When all the evidence is assembled, VA is responsible for determining whether the evidence supports the claims or is in relative equipoise, with the Veteran prevailing in either event, or whether a preponderance of the evidence is against the claims, in which case, the claims are denied. See Gilbert v. Derwinski, 1 Vet. App. 49 (1990). Neither the Veteran nor his representative has raised any issues with the duty to notify or the duty to assist. See Scott v. McDonald, 789 F.3d 1375, 1381 (Fed. Cir. 2015) (holding that "the Board's obligation to read filings in a liberal manner does not require the Board... to search the record and address procedural arguments when the veteran fails to raise them before the Board."); Dickens v. McDonald, 814 F.3d 1359, 1361 (Fed. Cir. 2016) (applying Scott to a duty to assist argument). Thus, the Board need not discuss any potential issues in this regard. In August 2016, the Veteran testified at a video conference hearing before the undersigned Veterans Law Judge (VLJ). In the October 2020 remand, the Board noted that the Veteran had recently been sent a letter that incorrectly advised him that he had a pending request for a Travel Board hearing. As he had already testified at the August 2016 hearing, the Regional Office (RO) sent the Veteran a letter in October 2020 asking that he inform VA if he would like another hearing. The Veteran did not respond requesting a hearing. Moreover, the Veteran has not alleged any deficiency with his hearing testimony as to the duties discussed in Bryant v. Shinseki, 23 Vet. App. 488, 496-97 (2010). In this regard, the Federal Circuit ruled in Dickens v. McDonald, 814 F.3d 1359 (Fed. Cir. 2016) that a Bryant hearing deficiency was subject to the doctrine of issue exhaustion as laid out in Scott v. McDonald, 789 F.3d 1375 (Fed. Cir. 2015). Thus, the Board need not discuss any potential Bryant problem because the Veteran has not raised that issue before the Board. Service Connection Service connection may be established for disability resulting from personal injury suffered or disease contracted in the line of duty in the active military, naval, or air service. 38 U.S.C. §§ 1131; 38 C.F.R. § 3.303. In order to prevail on the issue of service connection there must be (1) competent evidence of a current disability; (2) medical evidence, or in certain circumstances, lay evidence of in-service occurrence or aggravation of a disease or injury; and (3) competent evidence of a nexus between an in-service injury or disease and the current disability. See Shedden v. Principi, 381 F.3d 1163, 1167 (Fed. Cir. 2004); Jandreau v. Nicholson, 492 F.3d 1372, 1376-77 (Fed. Cir. 2007). To establish a right to compensation for a present disability, a Veteran must show: "(1) the existence of a present disability; (2) in-service incurrence or aggravation of a disease or injury; and (3) a causal relationship between the present disability and the disease or injury incurred or aggravated during service"-the so-called "nexus" requirement. Shedden v. Principi, 381 F.3d 1163, 1167 (Fed. Cir. 2004). Secondary service connection may be granted for a disability which is proximately due to, or the result of, a service-connected disorder. 38 C.F.R. § 3.310(a). Secondary service connection may be found in certain instances in which a service-connected disability aggravates another condition. If a Veteran was exposed to an herbicide agent during active military, naval, or air service, certain diseases shall be service connected if the requirements of 38 U.S.C. § 1116 and 38 C.F.R. § 3.307(a)(6)(iii) are met, even though there is no record of such disease during service, provided further that the rebuttable presumption provisions of 38 U.S.C. § 1113; 38 C.F.R. § 3.307(d) are also satisfied. 38 C.F.R. § 3.309(e). Service connection may also be established for those "chronic diseases" listed in 38 C.F.R. § 3.309(a) where the evidence shows a diagnosis manifest to a compensable degree within the presumptive period after service, or a continuity of symptomatology since service. See 38 C.F.R. §§ 3.303(b), 3.307; Walker v. Shinseki, 708 F.3d 1331, 1338-39 (Fed. Cir. 2013). 1. Entitlement to service connection for benign hypertrophy of the prostate (claimed as enlarged prostate) is denied. The Veteran is seeking service connection for benign hypertrophy of the prostate (claimed as enlarged prostate). The Veteran testified at the August 2016 hearing that he believes that the medications that he takes for his service-connected ischemic heart disease/coronary artery disease could be related to benign hypertrophy of the prostate. He also reported that his prostate would swell up and he could not urinate during service. In the September 2020 Written Brief Presentation, the representative suggested a link between the Veteran's prostate condition and in-service exposure to herbicides. Further, the Veteran has suggested throughout the course of this appeal that a doctor told him that stress from service could have caused his prostate disability. A review of his service treatment records reveals no complaints, treatment. or diagnoses related to the prostate. The Veteran was noted as having anxiety in a November 1967 service treatment record. He denied frequent or painful urination on the June 1969 Report of Medical History upon separation from service, and clinical evaluation of the genitourinary system was noted as normal on the June 1969 Report of Medical Examination. The Veteran was diagnosed with benign prostate hypertrophy without obstruction in a May 2013 private medical record from Shoals Urological Associates PC. In November 2017, the Veteran underwent a VA prostate examination, at which a diagnosis of benign prostatic hypertrophy was noted dating back to 2011. Upon review of the claims file and examination of the Veteran, the examiner concluded that the Veteran's claimed enlarged prostate was less likely than not caused by any in-service injury, event, or illness, as there was not documentation of this condition at separation and it was not diagnosed until 2011. The examiner also found that the Veteran's claimed enlarged prostate was less likely than not due to or the result of any service-connected condition. The cause of prostatic hypertrophy "is not clear [and] becomes more common as men age." There is no medical evidence to suggest that his enlarged prostate was caused by or due to any of his other medical problems or their treatments. In the July 2019 JMPR, it was found that the November 2017 VA examiner did not specifically discuss or provide rationale for whether the Veteran's prostate disability was caused by any medication he takes for his service-connected ischemic heart disease/coronary artery disease, nor did the examiner discuss the Veteran's contention that a doctor told him that stress from service could have caused his prostate disability. As such, in November 2020, several additional VA medical opinions were obtained on this matter. None of these VA opinions linked the Veteran's prostate disability to service, to in-service exposure to Agent Orange, or to a service-connected disability of any kind, to include treatment for a service-connected disability. Specifically, the examiner determined that the claimed condition was less likely than not incurred in or caused by the claimed in-service event, injury, or illness. The examiner noted that the Veteran's benign prostatic hypertrophy, unlike prostate cancer, has not been associated with herbicide exposure. The examiner found that the reported statement from the Veteran's doctor that "stress from service could have caused his prostate disability" is simply wrong. There is no medical evidence that "stress from service" has any association with prostate conditions (benign prostatic hypertrophy). The doctor's opinion is his alone and not supported by medical facts. The examiner went on to note that the studies cited in the September 2020 Written Brief Presentation are cohort studies and while an association may be inferred, no causality can be established. The November 2020 VA opinions also found that that the Veteran's condition is less likely than not proximately due to or the result of the Veteran's service-connected scars, tinnitus, hearing loss, neuropathy, diabetes mellitus, coronary artery disease, and posttraumatic disorder (PTSD). The examiner found that review of the current medical research has shown no physiologic, anatomic, or biomechanical associations for coronary artery disease, ischemic heart disease, tinnitus, scars, diabetic peripheral neuropathy of the extremities sensorineural hearing loss, diabetes mellitus, or a mental health condition (PTSD) to cause or permanently aggravate benign prostatic hypertrophy beyond its natural progression. The examiner noted that, while uncontrolled diabetes mellitus can cause urinary frequency, this is an entirely separate mechanism from benign prostatic hypertrophy. Benign prostatic hypertrophy typically causes urinary hesitancy or retention. The examiner further noted that, with regard to prescribed medications, while some medications can cause urinary hesitancy, medical literature does not associate any medications with the development of benign prostatic hypertrophy. Benign prostatic hypertrophy is a condition that affects all males and is age related. Nevertheless, the Veteran is not prescribed any medications that cause significant lower urinary tract symptoms. With regard to granting service connection on a presumptive basis, the Board notes that in-service exposure to herbicides has already been conceded. However, benign prostatic hypertrophy is not a disease listed under 38 C.F.R. § § 3.309(e) as being presumptively associated with Agent Orange or herbicide exposure. As such, the Board finds that service connection cannot be granted for benign prostatic hypertrophy as presumptively associated with Agent Orange exposure. With regard to granting service connection on a direct basis, regulations provide that service connection may be granted for any disease diagnosed after discharge, when all evidence, including that pertinent to service, establishes that the disability was incurred in service. 38 C.F.R. § 3.303(d). Currently, there is no medical evidence of record indicating that the Veteran had benign prostatic hypertrophy or a prostate disability of any kind in service. The Veteran did not report any related symptoms in service, and he specifically denied frequent or painful urination upon separation from service. Moreover, there is no medical evidence of record linking a current prostate disability of any kind to service, to include in-service exposure to Agent Orange or reports of in-service stress. The November 2020 VA medical opinions specifically do not link the Veteran's prostate disability to service, to include in-service herbicide exposure or reports of in-service stress. A rationale was provided for all opinions, so they are persuasive. As such, the Board finds that service connection cannot be granted for benign hypertrophy of the prostate (claimed as enlarged prostate) on a direct basis. With regard to granting service connection on a secondary basis, the Board finds there is no competent medical evidence of record indicating that the Veteran's benign hypertrophy of the prostate was caused or aggravated by a service-connected disability of any kind. Moreover, the November 2020 VA opinions specifically did not link the Veteran's prostate disability to a service-connected disability, to include medications used to treat a service-connected disability. A rationale was provided for all opinions, so they are persuasive. As such, the Board finds that service connection cannot be granted for benign hypertrophy of the prostate (claimed as enlarged prostate) on a secondary basis. The Board has considered the Veteran's assertions that he began experiencing symptoms related to his benign prostate hypertrophy during service, that his prostate disability is related to in-service Agent Orange exposure or in-service stress, and that medications he takes for his service-connected ischemic heart disease/coronary artery disease could be related to his benign hypertrophy of the prostate. Here, the Veteran's complaints as to duration of symptoms are certainly capable of lay observation. However, the Board finds that the cause of a currently diagnosed prostate disability is not capable of lay observation, as the Veteran does not have training in genitourinary diseases. Jandreau v. Nicholson, 492 F.3d 1372, 1377 (Fed. Cir. 2007). As such, the Veteran's opinion is afforded little weight in the analysis of whether a nexus between his current benign prostatic hypertrophy and his service or a service-connected disability exists. As for his assertions he had symptoms during service, there is no corroboration of such in his service records, and his denial of genitourinary symptoms at separation outweigh the allegations he makes now, in connection with a claim for benefits. The Board has considered the medical literature referenced by the Veteran's representative in the September 2020 Written Brief Presentation regarding prostate cancer and herbicide exposure. However, the Board finds that such generic texts, which do not address the facts of this particular Veteran's case, and with a sufficient degree of medical certainty, do not amount to competent medical evidence of causality. Sacks v. West, 11 Vet. App. 314 (1998); Libertine v. Brown, 9 Vet. App. 521 (1996); Beausoleil v. Brown, 8 Vet. App. 459 (1996). Moreover, the Board notes that the claim on appeal is for benign hypertrophy of the prostate (claimed as enlarged prostate), not prostate cancer. Further, as noted above, the November 2020 VA opinions specifically acknowledged these studies cited in the Written Brief Presentation when evaluating the specific circumstances of the Veteran's claim. As such, the Board finds this literature is afforded little weight in comparison to the November 2020 VA medical opinions. The Board notes that, by contrast, the medical professional who provided the November 2020 VA opinions reviewed the Veteran's claims file and offered opinions with supporting explanations as to why, in her medical judgment, the Veteran's benign prostatic hypertrophy is not related to service or to a service-connected disability. As such, the Board places the most significant weight on the November 2020 medical opinion, which finds against service connection. Thus, the Veteran's claim for service connection for benign prostatic hypertrophy must fail. Further, with regard to the Veteran's reports that a doctor told him that stress from service could have caused his prostate disability, the Board notes that a Veteran is competent to report information that a physician relays to him. Jandreau, supra. However, the Board notes that, in this case, these reports are not supported by any medical evidence of record. Further, the Board notes that a Veteran's recalling what a physician told him, i.e., "hearsay medical evidence," cannot constitute actual medical evidence, as "the connection between what a physician said and the layman's account of what he purportedly said, filtered as it was through a layman's sensibilities, is simply too attenuated and inherently unreliable to constitute 'medical' evidence." Robinette v. Brown, 8 Vet. App. 69 (1995). Thus, the Board finds these assertions are not probative. In summary, for the reasons stated above, the Board finds that the preponderance of the evidence is against the claim for service connection for benign hypertrophy of the prostate (claimed as enlarged prostate), and the benefit-of-the-doubt rule is not for application. 2. Entitlement to service connection for hypertension is denied. The Veteran is seeking service connection for hypertension. Specifically, in his September 2012 substantive appeal, the Veteran asserted that he believed that his hypertension began during service and suggested that it could be related in some way to his service-connected diabetes mellitus or his service-connected peripheral neuropathy. The Veteran testified at the August 2016 videoconference hearing that he found out that he had high blood pressure at about 27 or 28 years old and that he believes his hypertension is related to the stress he suffered in service. Moreover, in the September 2020 Written Brief Presentation, the representative suggested that there is a link between the Veteran's hypertension and his in-service exposure to Agent Orange. A review of the Veteran's service treatment records reveals no complaints, treatment, or diagnoses of hypertension or high blood pressure. The Veteran was noted as having anxiety in a November 1967 service treatment record. The Veteran specifically denied high or low blood pressure in a June 1969 Report of Medical History upon separation from service. A November 2017 VA examiner found that the Veteran's claimed hypertension is less likely than not related to any psychiatric disorder, as there is no link between psychiatric illness and the development of hypertension according to the Mayo Clinic. The examiner also noted that the Veteran is service connected for coronary artery disease and diabetes related to Agent Orange exposure, but that hypertension is less likely than not a result of those service-connected diagnoses, as the hypertension was documented prior to coronary artery disease and diabetes. As the November 2017 VA opinion did not address the issue of aggravation, an addendum medical opinion was obtained on this matter. A November 2019 VA opinion found that the Veteran's claimed condition is less likely than not proximately due to or the result of the Veteran's service-connected condition. Specifically, this opinion found that the Veteran's hypertension is less likely than not a result of his service-connected PTSD, diabetes mellitus, peripheral neuropathy of the bilateral upper and lower extremities, and coronary artery disease status post coronary artery bypass (CABG). It was noted that hypertension was documented prior to these conditions, and that the November 2017 VA examination documents hypertension as being diagnosed in 1970 (this is per the Veteran's history). It was further noted that the Veteran's claimed hypertension was less likely than not aggravated beyond its natural progression by the Veteran's service-connected conditions, to include PTSD, diabetes mellitus, peripheral neuropathy of the bilateral upper and lower extremities, and coronary artery disease status post CABG. It was noted that the medical evidence is not sufficient to support a determination of a baseline level of severity. The examiner responded "No" to the question of whether, regardless of an established baseline, the Veteran's hypertension was at least as likely as not aggravated beyond its natural progression by a service-connected disability. As the November 2019 VA opinion failed to provide a sufficient rationale for the determination that, regardless of an established baseline, the Veteran's hypertension was not at least as likely as not aggravated beyond its natural progression by a service-connected disability, this issue was remanded by the Board to obtain another medical opinion on this matter. Specifically, in November 2020, several additional VA medical opinions addressing this claim were obtained. None of these VA opinions linked the Veteran's hypertension to service, in-service exposure to Agent Orange, or a service-connected disability of any kind. Specifically, the examiner determined that the claimed condition was less likely than not incurred in or caused by the claimed in-service event, injury, or illness. The examiner noted that, while recent studies have shown an association with hypertension and veterans assigned to the Chemical Corps who had a high exposure to herbicides, there was no association with veterans with other military occupational specialties. The prospect of tetrachlorodibenzodioxin (TCDD) from Agent Orange in ground troops in Vietnam seems unlikely in light of the environmental dissipation of TCDD, little bioavailability, and the properties of the herbicides and circumstances of application that occurred. Photochemical degradation of TCDD and limited bioavailability of any residual TCDD present in soil or on vegetation suggest that dioxin concentrations in ground troops who served in Vietnam would have been small and indistinguishable from background levels even if they had been in recently treated areas. Laboratory and field data reported in the literature provide compelling evidence on the fate and dislodgeability of herbicide and TCDD in the environment. This evidence of the environmental fate and poor bioavailability of TCDD from Agent Orange is consistent with the observation of little or no exposure in the veterans who served in Vietnam. Appreciable accumulation of TCDD in veterans would have required repeated long-term direct skin contact of the type experienced in the United States Air Force Ranch Hand and Unites States Army Chemical Corps personnel who handled or otherwise had direct contact with liquid herbicide, not from incidental exposure under field conditions where Agent Orange had been sprayed. The Framingham study revealed that 90 percent of people 55 and over will develop hypertension eventually. Therefore, by definition, all Vietnam era veterans have a 90 percent chance of developing hypertension whether they were exposed to Agent Orange or not. The examiner concluded by referencing "NIH 2018". The November 2020 VA opinions also found that no anatomic, physiologic, or biomechanical mechanism has been shown for any of the Veteran's service-connected conditions to cause or permanently aggravate hypertension. Specifically, with regard to the submitted Written Brief, the studies cited in the Brief are cohort studies and, while an association is inferred, no causality can be established. The examiner noted that the Veteran's hypertension is less likely than not proximately due to or the result of the Veteran's service-connected scars, tinnitus, hearing loss, peripheral neuropathy, diabetes mellitus, coronary artery disease, and PTSD. The examiner found that review of the current medical literature has shown no anatomic, biomechanical, or physiologic associations for coronary artery disease, perception of sound (tinnitus), scars, diabetic peripheral neuropathy of the extremities, sensorineural hearing loss, diabetes mellitus, or a mental health condition (PTSD) to cause or permanently aggravate hypertension beyond its natural progression. The examiner did note that, while anxiety can cause a temporary elevation in blood pressure, it does not cause or permanently aggravate primary or secondary hypertension. With regard to granting service connection on a presumptive basis, the Board notes that in-service exposure to herbicides has already been conceded. However, hypertension is not a disease listed under 38 C.F.R. § 3.309(e) as being presumptively associated with Agent Orange or herbicide exposure. As such, the Board finds that service connection cannot be granted for hypertension as presumptively associated with Agent Orange exposure. With regard to granting service connection on a direct basis, there is no medical evidence of record indicating that the Veteran had hypertension or high blood pressure in service. The Veteran specifically denied high or low blood pressure in a June 1969 Report of Medical History upon separation from service. Moreover, there is no medical evidence of record linking current hypertension to service, to include in-service exposure to Agent Orange or reports of in-service stress. The November 2020 VA medical opinions specifically do not link the Veteran's hypertension to service, to include in-service exposure to Agent Orange or reports of in-service stress. A rationale was provided for all opinions, so they are persuasive. As such, the Board finds that service connection cannot be granted for hypertension on a direct basis. With regard to granting service connection on a secondary basis, the Board finds there is no competent medical evidence of record indicating that the Veteran's hypertension was caused or aggravated by a service-connected disability of any kind. Moreover, the November 2020 VA opinions specifically did not link the Veteran's hypertension to a service-connected disability. A rationale was provided for all opinions, so they are persuasive. As such, the Board finds that service connection cannot be granted for hypertension on a secondary basis. Additionally, the record does not show the presence of hypertension within one year of the Veteran's separation from active duty. See 38 C.F.R. § 3.309(a) (cardiovascular-renal diseases, to include hypertension, are chronic diseases subjective to presumptive service connection if shown in active service or to a compensable degree within one year of separation from active service). In the absence of such, continuity of symptomatology has no application. While the Veteran has alleged that he believed his hypertension began during his active service, the Veteran's blood pressure was recorded at 138/80 on his June 1969 Report of Medical Examination, and there is no medical evidence of record within the year following separation from service documenting high blood pressure. Moreover, the Veteran himself indicated on his March 2010 claim that his hypertension began in 1972, a September 2010 VA examination report noted 1972 as the date of hypertension diagnosis, and a VA treatment record problem list noted an onset of hypertensive vascular disease in 1978. This evidence renders his other reports of hypertension beginning while on active service to be inconsistent. Therefore, presumptive service connection under 38 C.F.R. §§ 3.303 (b), 3.307 (a)(3), and 3.309(a) is not warranted. See also Walker v. Shinseki, 708 F.3d 1331, 1338-39 (Fed. Cir. 2013). The Board has considered the Veteran's assertions that his hypertension began during service, that it could be related in some way to his service-connected disabilities, or that it could be related to the stress he suffered in service or in-service exposure to Agent Orange. Here, the Veteran's complaints as to duration of symptoms are certainly capable of lay observation. However, the Board finds that the cause of currently diagnosed hypertension is not capable of lay observation, as the Veteran does not have training in cardiovascular diseases. Jandreau v. Nicholson, 492 F.3d 1372, 1377 (Fed. Cir. 2007). As such, the Veteran's opinion is afforded little weight in the analysis of whether a nexus between his current hypertension and his service or a service-connected disability exists. As for his assertions it began during service, that is not credible, as discussed above. The Board has considered the medical literature referenced by the Veteran's representative in the September 2020 Written Brief Presentation regarding "limited or suggestive evidence" of an association between hypertension and herbicide exposure, as well as studies discussing an association between PTSD and cardiovascular disease. However, the Board finds that such generic texts, which do not address the facts of this particular Veteran's case, and with a sufficient degree of medical certainty, do not amount to competent medical evidence of causality. Sacks, supra.; Libertine, supra.; Beausoleil, supra. Moreover, as noted above, the November 2020 VA opinions specifically acknowledged these studies cited in the Written Brief Presentation when evaluating the specific circumstances of the Veteran's claim. As such, the Board finds this literature is afforded little weight in comparison to the November 2020 VA medical opinions. The Board notes that, by contrast, the medical professional who provided the November 2020 VA opinions reviewed the Veteran's claims file and offered opinions with supporting explanations as to why, in her medical judgment, the Veteran's hypertension is not related to service or to a service-connected disability. As such, the Board places the most significant weight on the November 2020 medical opinion, which finds against service connection. Thus, the Veteran's claim for service connection for hypertension must fail. In summary, for the reasons stated above, the Board finds that the preponderance of the evidence is against the claim for service connection for hypertension, and the benefit-of-the-doubt rule is not for application. 3. Entitlement to service connection for sleep apnea is denied. The Veteran is seeking service connection for sleep apnea. Specifically, the Veteran asserted in his September 2012 substantive appeal that his sleep apnea was caused by breathing Agent Orange in a tropical environment, which facilitated the ease of that chemical getting into his nose and throat. At the August 2016 hearing, the Veteran testified that he noticed his sleep issues about 1 or 2 months after his return from the Republic of Vietnam. Moreover, at a November 2017 VA examination, the Veteran reported that he believes his sleep apnea was caused by his PTSD and the accompanying treatment. Although the Veteran reported frequent trouble sleeping on his May 1967 Report of Medical History upon entrance into service, a review of the Veteran's service treatment records reveals no other complaints, treatment, or diagnoses of sleep apnea. He denied frequent trouble sleeping on the June 1969 Report of Medical Examination upon separation from service. In November 2017, the Veteran underwent a VA examination, and a VA opinion was obtained pertaining to his sleep apnea. At this examination, the Veteran reported that he suffers from PTSD but did not seek treatment until the late 1990s. He was diagnosed with PTSD, then, shortly after that, diagnosed with sleep apnea. The Veteran believes the sleep apnea was caused by the PTSD and the treatment from PTSD. Upon review of the claims file and examination of the Veteran, the examiner found that the Veteran's claimed sleep apnea was less likely than not incurred in or caused by any in-service event or illness. There was no documentation of sleep apnea while he was in service, and it was not diagnosed until the 1990s. In light of the Veteran's assertions regarding a relationship between his sleep apnea and PTSD, an additional medical opinion was obtained on this matter. Specifically, a November 2019 VA opinion found that the Veteran's claimed condition is less likely than not proximately due to or the result of the Veteran's service-connected condition. The opinion went on to note that the Veteran's claimed sleep apnea is less likely than not due to his service-connected PTSD, as there is no definitive medical literature to support correlation between the two disease processes. It was further noted that the Veteran's claimed sleep apnea was less likely than not aggravated beyond its natural progression by the Veteran's service-connected PTSD. Medical evidence is not sufficient to support a determination of a baseline level of severity. As the November 2019 VA opinion did not discuss a potential relationship between the Veteran's sleep apnea and his treatment for PTSD and did not provide a detailed rationale referencing the evidence of record or pertinent medical literature in finding that the Veteran's sleep apnea was not at least as likely as not aggravated beyond its natural progression, an additional medical opinion was obtained on this matter. In November 2020, several additional VA medical opinions were obtained. None of these VA opinions linked the Veteran's sleep apnea to service, to include in-service Agent Orange exposure, or to a service-connected disability of any kind, to include treatment for a service-connected disability. Specifically, the November 2020 VA opinions found that that the Veteran's condition is less likely than not proximately due to or the result of the Veteran's service-connected scars, tinnitus, sensorineural hearing loss, peripheral neuropathy, diabetes mellitus, coronary artery disease, and PTSD. The examiner found that review of the current medical research has shown no physiologic, anatomic, or biomechanical associations for coronary artery disease, ischemic heart disease, a perceived sound (tinnitus), scars, diabetic peripheral neuropathy of the extremities, sensorineural hearing loss, diabetes mellitus, or a mental health condition (PTSD) to cause or permanently aggravate obstructive sleep apnea beyond its natural progression. The examiner noted that medical literature does not support a mental health condition (PTSD) as causative or the potential for aggravation of the physiologic condition obstructive sleep apnea, which is due to upper airway soft tissue abnormalities/obesity. While some studies have suggested an association between obstructive sleep apnea and PTSD, they are cohort studies and do not show causality. The examiner also noted that, while certain medications have been associated with central sleep apnea, they are not associated with obstructive sleep apnea. The Veteran has not been diagnosed with central sleep apnea. Definite risk factors for obstructive sleep apnea include obesity, craniofacial abnormalities, and upper airway soft tissue abnormalities. The examiner went on to note that the studies cited in the September 2020 Written Brief Presentation are cohort studies and while an association may be inferred, no causality can be established. With regard to granting service connection on a presumptive basis, the Board notes that in-service exposure to herbicides has already been conceded. However, sleep apnea is not a disease listed under 38 C.F.R. § § 3.309(e) as being presumptively associated with Agent Orange or herbicide exposure. As such, the Board finds that service connection cannot be granted for sleep apnea as presumptively associated with Agent Orange exposure. With regard to granting service connection on a direct basis, there is no medical evidence of record indicating that the Veteran had sleep apnea in service, and there is no medical evidence of record linking sleep apnea to service, to include in-service exposure to Agent Orange. A lay account of trouble sleeping does not mean sleep apnea was present during service, as there can be many reasons for difficulty sleeping. Moreover, the November 2017 VA medical opinion specifically did not link the Veteran's sleep apnea to service. As such, the Board finds that service connection cannot be granted for sleep apnea on a direct basis. With regard to granting service connection on a secondary basis, the Board finds there is no competent medical evidence of record indicating that the Veteran's sleep apnea was caused or aggravated by a service-connected disability of any kind. Moreover, the November 2020 VA opinions specifically did not link the Veteran's sleep apnea to a service-connected disability, to include medications used to treat a service-connected disability. A rationale was provided for all opinions, so they are persuasive. As such, the Board finds that service connection cannot be granted for sleep apnea on a secondary basis. The Board has considered the Veteran's assertions that he began experiencing symptoms related to his sleep apnea shortly following service, and that his sleep apnea is related to in-service Agent Orange exposure or a service-connected disability. Here, the Veteran's complaints as to duration of symptoms are certainly capable of lay observation. However, the Board finds that the cause of a currently diagnosed sleep apnea is not capable of lay observation, as the Veteran does not have training in respiratory diseases. Jandreau v. Nicholson, 492 F.3d 1372, 1377 (Fed. Cir. 2007). As such, the Veteran's opinion is afforded little weight in the analysis of whether a nexus between his current sleep apnea and his service or a service-connected disability exists. As for his statements about difficulty sleeping during service, first, such was denied at separation, which weighs against the claims he makes now, and second, difficulty sleeping does not necessarily equate to sleep apnea. The Board has considered the medical literature referenced by the Veteran's representative in the September 2020 Written Brief Presentation regarding sleep apnea and cardiovascular disease. However, the Board finds that such generic texts, which do not address the facts of this particular Veteran's case, and with a sufficient degree of medical certainty, do not amount to competent medical evidence of causality. Sacks, supra.; Libertine, supra.; Beausoleil, supra. Moreover, as noted above, the November 2020 VA opinions specifically acknowledged these studies cited in the Written Brief Presentation when evaluating the specific circumstances of the Veteran's claim. As such, the Board finds this literature is afforded little weight in comparison to the November 2020 VA medical opinions. The Board notes that, by contrast, the medical professionals who provided the November 2017 and the November 2020 VA opinions reviewed the Veteran's claims file and offered opinions with supporting explanations as to why, in their medical judgment, the Veteran's sleep apnea is not related to service or to a service-connected disability (respectively). As such, the Board places the most significant weight on the VA medical opinions, which finds against service connection. Thus, the Veteran's claim for service connection for sleep apnea must fail. In summary, for the reasons stated above, the Board finds that the preponderance of the evidence is against the claim for service connection for sleep apnea, and the benefit-of-the-doubt rule is not for application. MICHELLE L. KANE Veterans Law Judge Board of Veterans' Appeals Attorney for the Board L. Durham, 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.