MIOARA DECUSARA, AURELIA ROMILA, LILIANA PAVEL, LUCIAN LAURENTIU ANDREI, MAGDALENA RUSU NEGRAIA, LUANA ANDREEA MACOVEI CHEMICAL CHANGES CAUSED BY CALCIUM DEPOSITION IN FORESTIER - ROTES - QUERROL’S DISEASE Calcium is involved in many biological processes. Hydroxyapatite provides bone mineralization, maintains cellular signaling, enzyme activity, nerve impulse transmission, muscle contraction and regulates blood clotting and membrane permeability. Calcium depositions may be caused by necrosis following trauma, connective tissue diseases, metabolic diseases, sarcoidosis, myeloma, metastases, chondrocalcinosis or calcium pyrophosphate dihydrate crystal deposition disease, cervical spondylosis, ankylosing spondylitis, ossification of the posterior longitudinal ligament of the spine and Forestier’s disease. Diffuse idiopathic skeletal hyperostosis (DISH) or Forestier-Rotes-Querrol’s disease is characterized by calcification of ligaments and entheses of the anterior vertebrae in the thoracic spine and sacroiliac joint bridging caused by abnormal proliferation of osteoblasts. At least four consecutive thoracic vertebrae are affected and the intervertebral disc space is preserved. Peripheral joints of heels, knees, elbows and pelvis may be also affected. Diagnosis is confirmed by radiographic findings with a candlewax-like appearance down the spine, on C2-C6 vertebrae. A total number of 37 patients with a median age of 63 years, of which 24 were male (64.86%) and 13 female (35.14%), were diagnosed with DISH at the Clinic of Geriatry of Galati County Emergency Clinical Hospital Sf. Apostol Andrei between 2006-2016. Differential diagnosis included ankylosing spondylitis and spondylosis deformans. DISH was found in patients aged over 50 years, with obesity and diabetes, based on radiographic findings. Drug therapy and physical therapy successfully provided pain relief, increased axial and peripheral mobility, improved physical function and optimal quality of life. None of our patients required surgery, as there were no cases with compromised airways and digestive tract involvement. Our study confirms that old age, obesity and type 2 diabetes are risk factors for diffuse idiopathic skeletal hyperostosis.