Talk to your doctor about whether supplementation of vitamin D is appropriate for you. Toxicity with supplementation is always a concern. Every adult should make sure to get 400 IU of vitamin D, and this may increase to 600 IU after the age of 70. In children, these numbers are lower and even 400 IU of vitamin D may be toxic. I would suggest reviewing your diet with your doctor. With your medical history in hand, and a full understanding of your diet and sunlight exposure, your doctor will be able to help you decide if vitamin D supplementation is appropriate or necessary for you.

Bibliography:
1. Felson DT. Niu J. Clancy M. Aliabadi P. Sack B. Guermazi A. Hunter DJ. Amin S. Rogers G. Booth SL. Low levels of vitamin D and worsening of knee osteoarthritis: results of two longitudinal studies. Arthritis & Rheumatism. 56(1):129-36, 2007 Jan.

2. McAlindon TE. 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. Annals of Internal Medicine. 125(5):353-9, 1996 Sep 1.