Bone joints & Connective Tissue Disease Research Center;
Golestan University of Medical Sciences;
Gorgan;
Iran;
Department of Epidemiology & Biostatistics;
School of Public Health;
Tehran University of Medical Sciences;
Tehran;
Iran;
Department of Internal Medicine;
Golestan University of Medical Sciences;
Gorgan;
Iran;
Department of Internal Medicine;
Tehran University of Medical Sciences;
Tehran;
Iran;