Examination of osteoarthritis (Degenerative joint disease) in Yoncatepe skeletal population

Paleopathological studies provide important insights into lifestyles, biological features, health conditions, and socio-cultural structures of past human populations. Osteoarthritis, being the most common postcranial pathology, is a disease caused by wear and tear on the synovial joints, and characterized by focal cartilage loss and specific reactions on joint surfaces of bones. Osteoarthritis is multi-factorial, yet the most common aetiological factors of the disease are age and physical activity. Intense and repetitive patterns of physical activity cause mechanical stress on the joints, triggering joint degeneration that leads to the formation of osteoarthritis. Given the aetiological characteristics of the disease, osteoarthritis studies provide valuable predictions on physical activity patterns and lifestyles of past human populations. In this study, we examine the prevalence of osteoarthritis on 13 different synovial joint groups of 119 adult specimens that were recovered within the years of 1998-2003 at excavations of Yoncatepe Castle and Necropolis (in modern Van, Eastern Turkey). During our examinations, we discovered the presence of more recent burials (presumably ~100 years old) that were mixed with the Urartu period burials, by the collapse of two of the graves in the necropolis. We included the newer skeletal material in the study, calling them "modern" skeletons, in order to investigate the changes in the joint health of these individuals overtime. The results of the study suggest that the highest prevalence rate of cranial joints of Urartu skeletons is seen in atlanto-occipital joint (30.76%), while in modern skeletons prevalence rate is found higher in temporomandibular joint (22.22%). The joint regions showing the highest disease prevalence in the postcranial body are the vertebrae (13.05%), knees (8.38%), and elbow (7.10%) joints of the Urartu period individuals. On the modern skeletons, the highest prevalence rate is assessed in the elbow (9.09%), knee (6.00%) and vertebral (5.26%) joints, respectively. This indicates that osteoarthritis patterns, and hence, the lifestyles of Yoncatepe skeletal populations are similar in both periods. Additionally, bilateral symmetry of osteoarthritis in extremity joints, and low incidence of severe osteoarthritis imply that primary osteoarthritis is more prevalent in the population, and age is a more important aetiological factor than physical activity. Osteoarthritis prevalence of the skeletal population is assessed as 6.21% in Urartu period individuals, and 3.44% in modern individuals. The decrease in osteoarthritis prevalence in modern period was found statistically significant. Additionally, in terms of osteoathritis prevalence Yoncatepe people in both periods were healthier than their contemporaneous ancient Anatolian populations. This suggests that the Yoncatepe individuals were not affected by the mechanical stress caused by physical activities that led to joint degeneration due to the relatively young population in both periods.