Osteoarthritis is also known as wear-and-tear arthritis. Yet, the disease is not common in parts to the world where people work hard with their joints to make a living. Rather, the disease is relatively rare. Thus, we would not consider too much work to be the cause. One would think that all of that work with the joints would lead to more wear and tear, no? Osteoarthritis is characterized by bone and cartilage degeneration in joints. This leads to pain and joint stiffness and can lead to disability. 
Vitamin D research.
Research has shown that those whose blood vitamin D measurements were in the middle and lowest thirds of serum vitamin D levels, had a threefold progression of osteoarthritis of the knee during a one-to-two year period. That is, when compared to those in the highest third. Low blood levels of vitamin D also predicted greater loss of cartilage in the joints.[1]
Other research demonstrates that in patients with arthritis of the knee, those with blood levels of vitamin D lower than 20 ng/ml (very low) have more disability. They also have more pain and more weakness than those with higher levels.[2], [3] Low vitamin D levels also correlate closely to greater knee pain and walking difficulty.[4]
Remember, unless it is stated that 25(OH)D levels are a result of supplementation or dietary sources, those levels are dependent on sun exposure. The research on osteoarthritis, discussed above, therefore, is really research on sun exposure.
Another horrific effect of arthritis.
Arthritic joints carry another devastating side effect. Hip replacement surgery is often prescribed for arthritic conditions: those people who go through total-hip-replacement procedures are 4.7 times as likely to have an ischemic stroke. They are also 4.4 times as likely to have a hemorrhagic stroke in the first two weeks post surgery.[5] Those stroke risks remain elevated for 6-12 weeks. The term “ischemic” means producing a local deficiency of blood supply by obstructing blood flow.
Sun exposure, therefore, has a protective effect against arthritis. Consequently, it has the potential to prevent hip-replacement surgery. In addition, it has the potential to prevent strokes.
Consider an article from the Express,[6] a UK online newspaper. It describes research published in the scientific journal, Annals of the Rheumatic Diseases,[7]stating the following: “Millions of people could protect themselves from crippling arthritis by getting a regular dose of sunshine. Scientists found that women with the highest levels of exposure to the sun – specifically Ultraviolet B (UVB) light – were 21 per cent less likely to develop the disease.”
Safely embrace the sun, help prevent osteoarthritis and safeguard your health.
[1] McAlindonTE, Felson DT, Zhang Y, Hannan MT, Aliabadi P, Weissman B, Rush D, Wilson PW, Jacques P. Relation of dietary intake and serum levels of vitamin D to progression of osteoarthritis of the knee among participants in the Framingham Study. Ann Intern Med 1996;125:353-9.
[2] Baker K, Zhang YQ, Goggins J. Hypovitaminosis D and its association with muscle strength, pain and physical function in knee osteoarthritis (OA): a 30-month longitudinal, observational study; American College of Rheumatology meeting; San Antonio, TX; Oct 16-21, 2004; abstract 17552. Also see http://www.medscape.com/viewarticle/538061
[3] Baker K, Zhang YQ, Goggins J. Hypovitaminosis D and its association with muscle strength, pain and physical function in knee osteoarthritis (OA): a 30-month longitudinal, observational study; American College of Rheumatology meeting; San Antonio, TX; Oct 16-21, 2004; abstract 17552. Also see http://www.medscape.com/viewarticle/538061
[4] Wang, J., Nuite, M., Wheeler, L.M., Badiani, P., Joas, J., Mcadams, E.L., Fletcher, J., Lavalley, M.P., Dawson-Hughes, B., Mcalindon, T.E. 2007. Low Vitamin D levels are associated with greater pain and slow walking speed in patients with knee osteoarthritis (KOA). In: American College of Rheumatology Scientific Meeting, 11/6/07-11/11/07, Boston, MA. 56(9supplement): S124. Accessed May 14, 2010 at http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=211611
[5] Lalmohamed A, Vestergaard P, Cooper C, de Boer A, Leufkens HG, van StaaTP, de Vries F. Hip replacement surgery and stroke. Stroke 2012;43(12):3225-9.
[6] http://www.express.co.uk/life-style/health/375632/Sun-helps-stop-arthritis. (accessed November 27, 2015).
[7] Arkema EV, Hart JE, Bertrand KA, Laden F, Grodstein F, Rosner BA, Karlson EW, Costenbader KH. Exposure to ultraviolet-B and risk of developing rheumatoid arthritis among women in the Nurses’ Health Study. Ann Rheum Dis. 2013 Apr;72(4):506-11