Interestingly, while having a high bone density affords a greater degree of protection against osteoporosis--the bone disease associated with aging that causes bones to become progressively more porous and brittle--and more likely to fracture--high bone density actually increases the risk of osteoarthritis.1 Thus patients with osteoporosis have a lower incidence of degenerative joint disorders such as finger osteoarthritis.2

At the same time, certain clinical markers for bone resorption can assess both the likelihood of developing osteoporosis as well as the extent of bone damage occurring after osteoarthritis has developed. Specifically, two collagen crosslinks measured in urine, pyridinium and d-pyridinium, provide information both on the pathogenesis of osteoarthritis as well as the rate of bone turnover crucial for osteoporosis (see Osteoporosis links). Because pyridinium is found extensively in bone cartilage, it is excreted in the urine in higher amounts when cartilage breaks down. For this reason, research indicates that it may serve as an important biomarker for assessing joint destruction in osteoarthritis and rheumatoid arthritis.3

Indeed, a study by researchers at the Centre for Rheumatic Diseases in Glasgow, Scotland found that elevated urinary pyridinium crosslinks (pyridinium and deoxypyridinium) correlated with osteoarthritis of the knee. They concluded that these crosslink markers could serve as useful indicators of disease activity in osteoarthritis.4

Other research findings have tied collagen crosslinks to even more specific clinical factors associated with arthritis. For example, investigators from the Royal London Hospital found that levels of crosslinks correlated with X-ray examinations in women with osteoarthritis--even in cases where the disease was as yet mild and asymptomatic.5 Another controlled study examining crosslink levels in patients with rheumatoid arthritis and osteoarthritis found clinical parameters of both diseases associated with high levels of these urinary markers. They concluded that "both pyridinium crosslinks in urine may therefore provide information on the stage, activity, level of bone involvement and efficacy of drug therapy in arthritic
diseases."6

The Bone Resorption Assessment provides practitioners with a convenient
noninvasive method for monitoring the clinical status of osteoarthritis and
other arthritic diseases, by measuring levels of the urinary crosslinks
pyridinium and deoxypyridinium.

References
1 Brandt K, Doherty M, Lohmander L, eds. Osteoarthritis. Oxford University Press, 1998.
2 Verrouil E, Mazieres B. Etiologic factors in finger osteoarthritis. Rev Rhum Engl Ed 1995;62(6 Suppl 1):9S-13S.
3 Robins SP, Stewart P, Astbury C, Bird HA. Measurement of the cross linking compound,
pyridinoline, in urine as an index of collagen degradation in joint disease. Ann Rheum Dis
1986;45(12):969-73.
4 MacDonald Ag, McHenry P, Robins SP, Reid DM. Relationship of urinary pyridinium crosslinks to disease extent and activity in osteoarthritis. Br J Rheumatol 1994;33(1):16-9.
5 Thompson PW, Spector TD, James IT, Henderson E, Hart DJ. Urinary collagen crosslinks reflect the radiographic severity of knee osteoarthritis. Br J Rheumatol 1992;31(11):759-761.
6 Seibel MJ, Duncan A, Robins SP. Urinary hydroxy-pyridinium crosslinks provide indices of
cartilage and bone involvement in arthritic diseases. J Rheumatol 1989;16(7):964-70.

All lab tests can be done through the mail in the privacy of your own home, except blood tests, we send you to a lab to have your blood drawn for these. After you pay for the test we mail you the kit, the results take two weeks, the test results will be mailed to us and we will call you to go over the results, its that easy! All tests include the consultation for the report of findings.

Click on area of interest on the right for more information.

Call our office for details. 800-956-7083 OR 818-707-3126.