Subsistence strategy changes: The evidence of entheseal changes

Abstract

Changes in subsistence strategy have caused some of the profoundest changes to the structure and health of humans. This study aims to test whether these changes have reduced work-load as assessed by entheseal changes. Entheseal changes, formerly called musculoskeletal stress markers (MSM), are thought to reflect muscle usage throughout life (although it is widely agreed that they have a multifactorial origin). This paper uses a meta-analysis of comparable published data to plot trends in time by muscle, enthesis type and sex. The results show that agriculturalists have the lowest scores for entheseal changes, with hunter-gatherers next highest and those working in industry the highest. These findings are the same for males and females, for most muscles and muscle groups. However, entheseal changes are highly correlated with increased age and the age distributions of the population samples analysed could not be compared. It is, therefore, possible that differences in age distribution of the samples is one of the reasons for this finding. Recommendations are provided to reduce this and other limitations for future meta-analyses.