ON REMAND
Before: Jansen, P.J., and Corrigan and T. G. Kavanagh,* JJ. T. G. Kavanagh, J.Plaintiff was awarded worker’s compensation benefits by a magistrate who found that plaintiff was totally and permanently disabled because of various physical disabilities that were causally connected to his employment as a truck mechanic. Plaintiff’s employer, Jones Transfer Company (hereinafter defendant) appealed, and the Worker’s Compensation Appellate Commission reversed the magistrate’s decision, ruling that plaintiff’s disabilities were not work-related. Plaintiff’s application for leave to appeal to this Court was originally denied, but our Supreme Court, on reconsideration, in lieu of granting leave to appeal, remanded the case to this Court for consideration as on leave granted. See 444 Mich 977 (1994). We now reverse the wcac’s decision and remand for further proceedings.
Plaintiff was employed by defendant for twenty-*47five years as a truck mechanic. His job duties, which are not disputed, are described in the magistrate’s decision as follows:
As a diesel mechanic, plaintiff described many tasks and various functions performed by him while working in defendant’s garage on tractor trailers; including, but not limited to repairing flat tires, changing tire rims, removing rear axle shafts, straightening bumpers, removing water pumps, springs, transmissions, king pins, taking out drive lines, repairing engines, water pumps, brakes and brake lines, removing and replacing alternators, pulling and repairing heaters, drive lines, heater coils, making electrical repairs and generally performing all mechanical work on defendant’s trucks.
In order to perform his mechanical work, plaintiff used various hand tools, impact tools, vibrating tools, wrenches and some of them were air driven. He further described the tools as being light and small, and others weighed 50 pounds and upwards, and having as much as 900 pounds of torque. For some tasks, he used a sledge hammer weighing 1C pounds or more to break away bolts and rims when repairing tires.
Often plaintiff had to lift truck parts weighing as much as 150 pounds. He indicated that hydraulic devices and chain falls were available to assist him with some tasks.
Further, much of plaintiff’s work required him to lift, bend, stoop, reach, stretch, climb, to lay on his back or stomach, work in awkward positions, stand off balance, walk and carry various equipment as the job required.
On May 1, 1986, plaintiff injured his right hand at work while installing a heater into a truck. Plaintiff received medical treatment and was off work for three weeks because of that injury. On July 10, 1986, plaintiff was injured again at work *48when he fell from a trailer onto a cement floor. Plaintiff complained of pain in his legs, ankles, knees, shoulders, and back. He was examined by a series of doctors and did not return to work because of continuing pain in his back and lower extremities, and also numbness and collapsing of his right leg.
On January 10, 1987, plaintiff fell and broke his left foot while walking in his yard at home. According to plaintiff, he fell because his right leg "gave away” because of numbness. Plaintiff continued to seek treatment for his back and lower extremity conditions and, about the same time, began seeking treatment for problems associated with his right hand and weakness of grips in both hands. The medical diagnoses generally attributed plaintiff’s physical complaints to advanced degenerative arthritis affecting his extremities, neck, and lower back, to carpal tunnel syndrome involving his wrists, and to ulnar nerve root entrapment at the elbow.
On February 17, 1987, plaintiff filed a petition for worker’s compensation benefits, asserting total and permanent disability due to the loss of the industrial use of his hands, arms, and legs. Defendant challenged plaintiff’s entitlement to benefits, in part, on the basis that plaintiff’s numerous physical complaints were not work-related. At a hearing before a worker’s compensation magistrate in June 1987, defendant introduced evidence that plaintiff was sixty-nine-years old and diabetic, that he had operated a twenty-acre farm since 1954, that he was off work for nine months in 1975 after injuring his foot on a farm combine, that he was receiving medication for an irregular heartbeat, and that he had a history of colon cancer. Defendant maintained that plaintiff’s numerous *49physical complaints were attributable to activities and medical conditions unrelated to his work.
After receiving testimony from several doctors concerning the nature, extent, and cause of plaintiffs injuries and physical complaints, the magistrate found that plaintiff’s hand pathology, elbow pathology, and carpal tunnel condition were all causally related to his work as a truck mechanic. Additionally, the magistrate found that plaintiff sustained a compensable injury to his shoulders, back, legs, ankles, and knees arising from his fall at work on July 10, 1986, that plaintiff’s ongoing lower extremity and back pathologies were causally related to the fall at work, and that, plaintiff’s fall at home on January 10, 1987, resulted from his ongoing lower extremity pathology. The magistrate concluded that plaintiff was totally and permanently disabled because of the loss of the industrial use of both lower extremities, but that plaintiff had not lost the industrial use of his upper extremities. The magistrate, however, denied plaintiffs request for nursing care benefits.
Both parties appealed the magistrate’s decision to the wcac, raising several issues. The wcac reversed the magistrate’s decision, finding that the evidence before the magistrate was insufficient to show that plaintiff’s injuries and disabilities were work-related. Although acknowledging that plaintiff had presented medical testimony "asserting work-relatedness,” the wcac ruled that "[t]he record in this case firmly establishes that plaintiff had a history of non-work-related physical exertions and problems . . . [which] easily and directly explains the sources for plaintiffs physical complaints.” The wcac concluded that, "[i]n the context of this strong causal evidence, plaintiff failed to provide substantial evidence by which to attach any contributing relationship to his work, whether *50cumulatively over time or through the two specific injuries plaintiff had in ,1986.” In light of its reversal on the basis, that the injuries were not related to work, the wcac found it unnecessary to address the other claims raised by the parties.
Plaintiff now argues, and we agree, that the wcac erred in reversing the magistrate’s findings of work-relatedness.
In reviewing a magistrate’s decision, the wcac must perform both a qualitative and quantitative review of the record. MCL 418.861a(13); MSA 17.237(861a)(13). The wcac’s review is not de novo, however, and the wcac may not merely substitute its opinion for that of the magistrate. Kovach v Henry Ford Hosp, 207 Mich App 107, 111; 523 NW2d 800 (1994). A magistrate’s findings of fact are to be regarded as conclusive if supported by "competent, material, and substantial evidence on the whole record.” MCL 418.861a(3); MSA 17.237(861a)(3).
On review by this Court, findings of fact by the wcac are conclusive if there is any competent evidence to support them. MCL 418.861a(14); MSA 17.237(861a)(14); Holden v Ford Motor Co, 439 Mich 257, 263; 484 NW2d 227 (1992). However, a decision of the wcac is subject to reversal if the wcac operated within the wrong legal framework or its decision was based on erroneous legal reasoning. O’Connor v Binney Auto Parts, 203 Mich App 522, 527; 513 NW2d 818 (1994). In Holden, supra at 269, our Supreme Court stated:
If it appears on judicial appellate review that the wcac carefully examined the record, was duly cognizant of the deference to be given to the decision of the magistrate, did not "misapprehend or grossly misapply” the substantial evidence standard, and gave an adequate reason grounded in *51the record for reversing the magistrate, the judicial tendency should be to deny leave to appeal or, if it is granted, to affirm. . . .
In this case, we find that reversal of the wcac’s decision is justified because the wcac’s finding that "plaintiff failed to provide substantial evidence by which to attach any contributing relationship to his work” is not supported by competent evidence and because other reasons given by the wcac for reversing the decision of the magistrate are not grounded in the record.
An employee bears the burden of proving the relationship between an injury and the workplace by a preponderance of the evidence. Morris v Soloway, 170 Mich App 312, 315; 428 NW2d 43 (1988). An employee is entitled to compensation where the nexus between the employment and the injury is sufficient to conclude that the injury was a circumstance of the employment. Collier v J A Fredman, Inc, 183 Mich App 156, 161; 454 NW2d 183 (1990). Worker’s compensation benefits are payable not only for a disability caused solely by working conditions, but also for any preexisting illness, disease, or deterioration accelerated or aggravated by the workplace and for any injury that was caused by work coupled with a preexisting condition. Kostamo v Marquette Iron Mining Co, 405 Mich 105, 116; 274 NW2d 411 (1979). Conditions of the aging process are compensable if contributed to, or aggravated or accelerated by, the employment in a significant manner. MCL 418.301(2); MSA 17.237(301)(2) and MCL 418.401(2) (b); MSA 17.237(401)(2)(b).
In the instant case, the wcac stated that reversal was warranted because, with regard to plaintiff’s injuries, plaintiff "failed to provide substantial evidence by which to attach any contributing *52relationship to his work.” The wcac also stated that the medical testimony "pointed strongly” toward plaintiffs diabetes as the "fundamental basis” for his extremity complaints and carpal tunnel problem. Indeed, the wcac stated that Dr. Donald Austin, a defense witness, had "explicitly connected plaintiffs carpal tunnel nerve problems to his diabetes.” A review of the record discloses that these reasons are not grounded in the record.
Dr. Jerry Taylor, who is an osteopathic physician and surgeon, agreed that plaintiff had longstanding degenerative osteoarthritis of both upper extremities and also carpal tunnel syndrome involving both wrists. He opined, however, that plaintiffs job duties as a mechanic led to the development of the carpal tunnel syndrome and also accentuated the development of plaintiffs arthritis in his hands, wrists, and arms. Dr. Taylor also explained the basis of his opinions. Regarding plaintiffs carpal tunnel syndrome, Dr. Taylor stated:
It’s my impression that the carpal tunnel syndrome that he has bilaterally was related to the repetitive and heavy use of his hands. So, in this order of sequence, number one, the use of his hands caused carpal tunnel syndrome. The carpal tunnel syndrome having been present for a long period of time caused the thenar atrophy in both places.
Most people feel that work-related carpal tunnel syndrome results from a microtenosynovitis, a swelling of the tendons, the nine tendons that are in the carpal tunnel, that they swell and they eventually compress the nerve. And the use of vibrating tools, for instance, would, over a period of time, [cause] this tenosynovitis to develop. The same is true when one is flex[ing] and extending *53the wrists and doing a lot of grasping, twisting, pushing and pulling. It eventually cause[s] the tenosynovitis and eventually the carpal tunnel syndrome.
Regarding plaintiffs degenerative arthritis, Dr. Taylor stated:
Degenerative arthritis and osteoarthritis are basically the same conditions. They are not conditions that are due to any disease within the person’s body as rheumatoid arthritis which is something a person develops which is in the bloodstream, for instance.
Osteoarthritis, in layman’s terms, is a wearing out of the joint surfaces. . . . It’s my feeling that the joint surfaces have worn out and deteriorated, partially because of the fact he’s done extremely heavy work for a long period of time, thus, the wearing out of the joint surfaces is another way of saying that the arthritis he has developed is because the joints have degenerated from wear and tear, a portion of which is certainly related to his job.
Dr. Taylor further opined that plaintiffs conditions were related to plaintiffs employment in a significant manner.
Dr. Taylor: Yes, I feel the conditions I diagnosed are related to his employment and the injury of July.
Q: Do you have an opinion, as to whether the relationship of the job duties and his employment is related in a significant manner?
Dr. Taylor: Yes, it is significant.
Dr. Frank Cullis testified that trauma contributes to arthritis, and he likewise opined that plaintiffs work activities and fall at work were "significant factors” in the development of plaintiffs up*54per and lower extremity pathologies, as well as his neck and back conditions.
Dr. Austin agreed that repeated use of power tools and hand tools would be a "definite factor” in the cause of carpal tunnel syndrome and ulnar nerve root entrapment. In response to a hypothetical question describing plaintiffs job duties and medical history,1 Dr. Austin agreed that "the most likely factor involved in his carpal tunnel syndrome would be his job.” During later questioning, Dr. Austin again opined that plaintiffs work as a mechanic "was the significant contributing factor to the development” of plaintiffs ulnar nerve entrapment and carpal tunnel conditions. Dr. Austin also agreed that plaintiffs July 10, 1986, fall at work could have aggravated plaintiffs neck and back conditions.
Defense witness Dr. Fred Lamb also agreed that repetitive activity can contribute to degenerative arthritis and another defense witness, Dr. Herman Remsperger, agreed that repetitive use of power tools can lead to carpal tunnel syndrome.
The foregoing medical testimony constituted substantial evidence under MCL 418.861a(3); MSA 17.237(861a)(3) on which the magistrate could find that plaintiffs disabilities were work-related.
Regarding the role of plaintiffs diabetes, Dr. Austin testified that diabetics are more "prone” to nerve entrapment syndromes and, therefore, opined that "some” of plaintiffs carpal tunnel and ulnar nerve problems could be "at least partly due to that diabetes.” He added, however, that the repetitive use of power tools and wrenches would also be a "definite factor” in those conditions. More significantly, in the context of the hypotheti*55cal question describing plaintiffs job duties, Dr. Austin stated:
I think the diabetes makes him more prone to the involvement of it, but the primary cause would be the repetitive activity itself. [Emphasis added.]
The remainder of the record is devoid of support for the wcac’s characterization of the medical evidence as "pointing] strongly” toward plaintiffs diabetes as the "fundamental basis” for his extremity complaints and carpal tunnel problems. To the contrary, Dr. Taylor specifically negated plaintiffs diabetes as a contributing cause of his conditions, explaining:
[Plaintiff] was diagnosed as having diabetes in the late 1960’s, which would be a rather late onset of diabetes. From a medical point of view, diabetes that begins in later life is not usually as significant as diabetes that develops in a child or young adult. Furthermore, we tend to classify diabetes, the severity of diabetes on the basis of whether or not it ever required insulin to control it. Obviously, the more severe cases of diabetes require the use of insulin . . . where the less severe cases don’t require it.
In this case, this man has never required insulin and based on the fact his diabetes was rather late onset and based upon the fact that it never required the use of insulin, it is my feeling that it was not a significant case of diabetes and the significance in this case is this: That carpal tunnel syndrome and other neuropathies can be related to long-standing cases of diabetes, the type of diabetes being the ones that required insulin. The milder cases of diabetes, as I believe was true in this case, are not involved in neuropathies. So, I don’t feel his carpal tunnel syndrome and/or his ulnar neuropathies in either upper extremity are in any way related to the fact he has had mild diabetes for several years.
*56Dr. Lamb also stated that plaintiffs degenerative arthritis was not related to his diabetes. Dr. Cullis stated, without elaboration, that plaintiffs diabetes "may play some part” in his carpal tunnel condition, but that it was not a factor with regard to plaintiffs lower extremity conditions. On this record, the wcac erred in finding that the evidence "pointed strongly” toward plaintiffs diabetes as the "fundamental basis” for his extremity complaints and carpal tunnel problems.
While it is true, as the wcac recognized, that plaintiff has "a history of non-work-related physical exertions and problems,” there was substantial evidence supporting the magistrate’s finding that plaintiffs present complaints were related to his employment as a truck mechanic. The wcac simply substituted its opinion for that of the magistrate in concluding otherwise. As this Court observed in Kovach, "this is not proper review pursuant to statute and Holden, supra.”
Accordingly, for the reasons stated, we reverse the decision of the wcac and reinstate the decision of the magistrate with regard to the issue of work-relatedness and remand this case to the wcac for consideration of the remaining issues that were raised by the parties but not considered by the wcac.2
Reversed and remanded. We do not retain jurisdiction.
Each of the assumptions employed in the hypothetical were supported by evidence in the record.
In light of our disposition, it is unnecessary to address plaintiffs claim that reversal is required on the alternative ground of "pro-defendant” bias on the part of one of the wcac panel members. Furthermore, we note that plaintiff did not raise this issue below and, therefore, it was not preserved. Benavides v Edward C Levy Co, 117 Mich App 722, 726; 324 NW2d 149 (1982). Cf. Armstrong v Ann Arbor, 58 Mich App 359, 368-369; 227 NW2d 343 (1975).