BEAM, Circuit Judge.
On December 5, 1979, Claude Robinson filed a claim for black lung benefits with the Department of Labor under the Black Lung Benefits Act (Act), 30 U.S.C. §§ 901-945 (1988). After a hearing on October 5, 1984, an Administrative Law Judge denied Robinson’s claim. The Benefits Review Board affirmed the AU’s decision on February 28, 1990. Robinson appeals. We affirm.
I. BACKGROUND
A lengthy review of the evidence presented at Robinson’s hearing before the AU is not necessary for our purposes; a short discussion of the AU’s reasoning and the BRB’s affirmance will be sufficient. Applying the standards governing eligibility for black lung benefits contained in 20 C.F.R. § 727.203, the AU initially found that sufficient evidence existed to invoke an interim presumption of Robinson’s total disability due to pneumoconiosis (black lung). Robinson had worked as a miner for thirteen years and ventilatory studies, blood gas studies, and medical opinion raised the interim presumption under section 727.203(a)(2), (3), (4). The AU found that conflicting x-ray evidence failed to raise the interim presumption under section 727.203(a)(1).
Although sufficient evidence existed to raise the interim presumption, the AU ultimately concluded that the evidence as a whole rebutted the presumption under section 727.203(b)(2), (3), (4). The AU found that Robinson was able to do his usual coal mine work or comparable and gainful work, that Robinson’s disability did not arise out of coal mine employment, and that the medical evidence indicated that Robinson did not have pneumoconiosis.
In reaching his final decision, the AU credited the opinion of one examining physician, Dr. Lloyd Hollinger, over that of another, Dr. Max Gutensohn. In Dr. Hol-linger’s view, Robinson was not suffering from pneumoconiosis, but rather from “chronic obstructive pulmonary disease of a very mild degree [that] can be solely related to his smoking history.” Hollinger Report, Sept. 26, 1980, at 2. Dr. Guten-sohn, in contrast, believed that “[i]t would appear, in as much as [Robinson] has not been exposed to any other irritant except for smoking for some periods of time, that he is disabled due to previous coal mine employment.” Gutensohn Report, Sept. 10, 1984, at 2. The AU relied on Dr. Hollinger’s opinion because it was more detailed, less tentative, and included a specific finding that Robinson could return to his work as a caterpillar operator whereas Dr. Gutensohn’s opinion failed to address this issue.
Robinson appealed the AU’s decision pro se and the BRB construed his arguments as an assertion that the AU’s order was not supported by substantial evidence on the record as a whole. The BRB affirmed the AU’s order, concluding that substantial evidence supported the AU’s finding concerning rebuttal of the interim presumption under section 727.203(b)(2). In particular, the BRB held that the AU’s decision to credit Dr. Hollinger’s opinion over Dr. Gutensohn’s on the issue of whether Robinson was able to work as a caterpillar operator was rational. Because rebuttal of the interim presumption under section 727.203(b)(2) was sufficient to uphold the AU’s decision, the BRB declined to review the ALJ’s other findings.
II. DISCUSSION
Our review of the BRB’s order is very limited. The BRB cannot set aside the AU’s factual findings unless the findings are not supported by substantial evidence in the record as a whole. See 30 U.S.C. § 932(a) (1988); 33 U.S.C. § 921(b)(3) (1988). If the AU’s findings satisfy this requirement, the BRB must affirm even though it might have reached a different conclusion than the AU were it the fact-finder. E.g., Brown v. Director, Office of Workers’ Compensation Programs, 914 F.2d 156, 158 (8th Cir.1990). In particular, the decision to credit one of two conflicting medical opinions as better documented and reasoned belongs to the AU as fact-finder. See Phillips v. Director, Office of Workers’ Compensation Programs, 768 F.2d 982, 984 (8th Cir.1985). Our role on appeal is merely to assure that the BRB adhered to the proper standard of review. To fulfill this role, we examine the AU’s findings under the same standard. E.g., Brown, 914 F.2d at 158.
After review of the record before the AU, we agree with the BRB that the AU’s decision to credit Dr. Hollinger’s opinion over Dr. Gutensohn’s is supported by substantial evidence in the record as a whole and is not contrary to law. Robinson asserts that the AU’s reliance on Dr. Hollinger is improper as a matter of law because Dr. Hollinger’s diagnosis was the result of subjective opinions concerning pneumoconiosis hostile to the spirit of the Act. In particular, Robinson contends that Dr. Hollinger testified that he would never diagnose pneumoconiosis absent a positive x-ray. The BRB has held that an AU may discount the opinion of a physician who holds such a view because the view directly contravenes a specific provision of the Act. Nagle v. Barnes & Tucker Co., 1 Black Lung Rep. (MB) 1-961, 1-965 (Ben.Rev.Bd.1978); accord Black Diamond Coal Mining Co. v. Benefits Review Bd., 758 F.2d 1532, 1534 (11th Cir.1985). The present-case, however, is distinguishable. Dr. Hol-linger’s exact testimony was that someone would have to have an abnormal x-ray if they were “totally impaired” due to pneu-moconiosis, and merely agreed that he “would not be inclined” to diagnose pneu-moconiosis absent an abnormal x-ray. Hol-linger Deposition Transcript at 50-51. Furthermore, read in its full context, Dr. Hol-linger’s testimony was that considering Robinson’s smoking history, the absence of a positive x-ray led him to conclude that Robinson’s respiratory problems were the result of smoking and not pneumoconiosis. Id. at 33. On cross-examination, Dr. Hol-linger expressly stated that his conclusion was based on all the medical information available to him (which included the results of ventilatory studies, arterial blood gas tests, an electrocardiogram, as well as two x-rays). Id. at 38. While Dr. Hollinger’s opinion regarding Robinson was certainly based in part on the lack of a positive x-ray, it was not based solely on this. His opinion, therefore, was not based on a medical theory hostile to the Act.
Robinson further argues that the AU should have credited Dr. Gutensohn’s opinion because it was based on more recent information. Dr. Hollinger’s opinion was based on a personal examination and the results of tests performed in 1980, including negative x-rays. Dr. Gutensohn’s opinion was based on a personal examination and the results of tests performed in 1984, including a positive x-ray (which was the only x-ray taken since 1980). As pneu-moconiosis is a progressive disease, the AU certainly should consider the temporal proximity of conflicting test results in determining which of two different medical opinions to credit. See Mullins Coal Co. v. Director, Office of Workers’ Compensation Programs, 484 U.S. 135, 151-52, 108 S.Ct. 427, 436, 98 L.Ed.2d 450 (1987). Temporal proximity, however, is simply a factor to be considered, not a controlling one. Viewing the record as a whole, we conclude that substantial evidence exists to support the AU’s decision to credit Dr. Hollinger’s opinion that Robinson’s respiratory problems were the result of his smoking history and not his exposure to coal dust, despite the comparative age of the information upon which the opinion was based.
Robinson also challenges the AU’s decision to credit the portion of Dr. Hollinger’s opinion concerning Robinson’s ability to return to work as a caterpillar operator. Robinson emphasizes that Dr. Hollinger did not ask Robinson about the specifics of his job, which included cleaning mud from the caterpillar’s tracks at the end of the shift. Robinson introduced evidence that this was the most strenuous part of the job. See Ray Williams Deposition Transcript at 10. Dr. Hollinger, however, did testify that he was familiar with the general operation of heavy machinery, including caterpillars, and Dr. Gutensohn expressed no opinion whatsoever on the issue. Furthermore, statements which Robinson made during an interview with a representative of his former employer implied that he retired mainly because of his age, 65, and not his respiratory problems. Employer’s Exhibit 3, at 4, 8. Given the high degree of deference that we must accord the AU’s findings of fact, we are unable to hold that the AU’s decision to credit this portion of Dr. Hol-linger’s testimony is not supported by substantial evidence.
III. CONCLUSION
We conclude that the AU’s decision to credit Dr. Hollinger’s opinion over Dr. Gu-tensohn’s is supported by substantial evidence in the record as a whole. Because Dr. Hollinger’s opinion that Robinson is able to return to work as a caterpillar operator is sufficient to rebut the interim presumption of pneumoconiosis and to uphold the AU’s denial of Robinson’s claim for black lung benefits, we affirm the BRB’s order.
. The dissent asserts that Dr. Hollinger must have based his conclusion solely on the lack of a positive x-ray, because the other test results available to him raised a presumption of pneu-moconiosis. We do not agree with the dissent’s analysis. The results of the ventilatory studies and arterial blood gas tests merely raised a presumption of pneumoconiosis as a matter of law because of Robinson’s coal mining experience, see 20 C.F.R. § 727.203(a)(2), (3), they did not require a diagnosis of pneumoconiosis as a matter of medical science. Moreover, the blood gas tests revealed a significant amount of car-boxyhemoglobin, which was related to Robinson’s smoking. Hollinger Report, Sept. 26, 1980, at 3. Dr. Hollinger’s conclusion, therefore, was not inherently inconsistent with the other test results.
. The dissent also asserts that the AU's reliance on Dr. Hollinger’s opinion is misplaced because Dr. Hollinger’s report is inaccurate regarding Robinson’s coal mining experience. Under the circumstances, however, we find this argument unconvincing. Both Dr. Gutensohn’s and Dr. Hollinger’s reports contain some inaccurate background information. Dr. Gutensohn, for example, significantly understated the extent of Robinson’s smoking history. Robinson testified that he smoked one can of pipe tobacco every week or week and one half for twelve years, up to one pack of cigarettes per day for eleven years, and up to three to four cigarettes per day for four more years. Hearing Transcript at 29-30. According to Dr. Gutensohn’s report, Robinson smoked about one pack per day for twelve years and for part of that time, had just one cigarette after meals. Gutensohn Report, Sept. 10, 1984, at 1. Thus, in this case, the ALJ had to credit one medical opinion based in part on inaccurate information over another opinion with the same flaw. Viewing the record as a whole, we believe that substantial evidence exists to support the AU’s decision here.