Effects of age and gender on the frequencies of spondylolysis and spina bifida occulta in a skeletal collection from Golovin Bay, Alaska

Scott S. Legge, Macalester College

Abstract

It has been suggested that the occurrence of spondylolysis is dependent on both gender and age. This study determined the frequency of spondylolysis in a skeletal population from Golovin Bay, AK in relation to gender and age differences. Spondylolysis was characterized only in individuals with complete lumbar regions (n=52). The overall frequency for this population is 46.9%. No statistical differences were found between males and females, and the frequency was independent of age.

Possible causes for spondylolysis include a genetic predisposition for lysis or microfractures from repetitive stresses on the lower back (see review Newell, 1995). The occurrence of spondylolysis in the Golovin Bay skeletal collection was compared with published findings for circumpolar and non-circumpolar groups with the assumption that populations relying on similar subsistence bases may encounter similar low-back stresses. The values for this population resemble those of the Eskimos of Greenland or northern Alaska more than Eskimos of southern Alaska or non-Eskimo populations. This suggests an etiology for spondylolysis based on similar lifestyles rather than genetics.

The frequency of spina bifida occulta was also examined because of suggestions that it is related to spondylolysis (Frederickson et al., 1984). The frequency of spina bifida occulta is 12.8% in the Golovin Bay skeletal collection, and statistical analysis indicates that it is independent of spondylolysis. American Journal of Physical Anthropology, Vol. 111, Supplement 30: 208 (Abstract).