An attempt was made to determine whether a relationship exists between ankylosing spondylitis (AS) and hyperparathyroidism (HP). Twenty patients with definite AS, studied for biochemical evidence of HP, did not show consistent abnormalities in serum calcium, phosphorus, alkaline phosphatase, or parathyroid hormone levels or in bone-density measurements. Reviewing roentgenograms of 39 patients with HP showed one patient with sacroiliitis, and one of the 28 hyperparathyroid patients tissue-typed as HLA B27-positive. Both AS and HP are independent entities that have no causative or pathological relationship to each other.
(JAMA 240:759-761, 1978)
Goldin R, Brickman AS, Massry SG, Bluestone R. Ankylosing Spondylitis and Hyperparathyroidism. JAMA. 1978;240(8):759–761. doi:10.1001/jama.1978.03290080049025