Lumbar spondylolysis in ancient Siberian Eskimo

Abstract

Previous studies have shown that North American and Greenland Arctic groups are characterized by high incidence of spondylolysis. The hypotheses explaining the high predilection to spondylolysis in these populations range from genetic predisposition to lifestyle characteristics. To date, however, no study assessed the presence of spondylolysis in the Siberian Eskimo. Thus, the current study presents new data from the Asian side of the Beringia, the original homeland of the North American and Greenland Inuit groups. The skeletal material originates from the Ekven burial site in Chukchi Peninsula, Russia. Most burials belong to the Old Bering Sea tradition of marine mammal hunters, embracing the period from the beginning of the 1st to the beginning of the 2nd millennium AD. Totally, 71 individuals were studied. Spondylolysis was present in 38% of individuals and in 11% of studied lumbar vertebrae, with higher incidence in juveniles and young adults compared with other ages and in males compared with females. There was an evident increase in the severity of the stress fractures from adolescence to middle adulthood (i.e., more vertebrae affected per individual and higher proportion of bilateral fractures). The reported incidence of spondylolysis in the Ekven is in the range of the values reported for the North American and Greenland Inuit groups and is expectedly high against the values for groups of European and African ancestry. Although the accumulation of gene variants responsible for spondylolysis in Arctic groups is possible, it is more plausible that some adaptive morphological characteristics make them prone to fatigue fractures of the lower spine in the conditions of the specific physical activity.