The purpose of this study is to further the understanding of the relationship between age and entheseal changes by using trends in living Americans compared to skeletal remains of modern Americans, and applying the knowledge to the bioarchaeological record. Documentation of age, activity level, body mass index, stature, and body mass was combined with entheseal change scores gathered from the upper extremity to statistically test the relationship between age and entheseal change with and without controls of documented demographic and health factors. An active subsample was constructed using self‐reported repetitive activities and discernment of position within stated career. Fibrocartilaginous entheses reported in the literature to be better suited to estimate occupation were separated from other entheses. A series of Cochran–Mantel–Hanzel and analysis of variance‐based tests were applied to the data. Interobserver reliability was also examined with a linear‐weighted Cohen's kappa. Statistical analysis shows only 1 enthesis has a significant positive relationship with age and 2 with activity. Body mass index and body mass were associated with 9 entheses that were spread across the occupation‐associated fibrocartilaginous entheses and all other entheses. Interobserver reliability ranged from low to substantial agreement. Interobserver error estimates suggest some entheses are more reliable than others. Results provide little support for a relationship between age and entheseal changes and activity and entheseal changes, which partially coincides with previous research. An increase in activity with age in our sample, around the age of retirement, mirrors trends in living Americans and supports our conclusions. For bioarchaeologists, these results suggest interpretations of entheses should be cautiously applied and revolve around body size rather than activity levels.

A number of studies have now shown a markedly higher prevalence of multiple sclerosis (MS) in northern Scotland.' The prevalence rates appear particularly high in the islands, with Orkney having the highest rate reported anywhere in the world.23Our specific task in this paper is to consider the possible effect of differential migration upon prevalence. The hypothesis is that part or all of the difference in prevalence may be the result of differences in migration, and the possibility that persons with MS are less likely to migrate, and that those who do are most likely to return after onset of the disease.Bradford Hill's4 pioneering study of the effect of migration on mortality rates produced the earliest clear evidence for our migration hypothesis. Additional and more recent evidence has come from those studies which have used height as an index of health status; most of these show that migrants are invariably taller than residents.5 The best British data are those collected by Martin,6 the Scottish Council for Research in Education,7 and Illsley, Finlayson, and Thompson.8 The latter are of particular interest because Aberdeen is the main destination for migrants from Orkney and Shetland. The authors demonstrated that migrants into the city were taller and had lower prematurity and perinatal death rates than Aberdeen women, and that the superiority was most marked among the more distant in-migrants.In the absence of studies of MS which provide a direct test of the migration hypothesis, this paper proceeds on the assumption that persons with MS migrate differently from the remaining section of the population. Assuming that those with MS are less likely to migrate, and that those who do are more likely to return, can we account for the observed prevalence rates? Before examining the special situations of Orkney and Shetland, we consider a number of factors which might plausibly affect prevalence rates.(1) FACTORS AFFECTING PREVALENCE RATES For heuristic purposes we postulate that the aetiology of MS is unaffected by geography, by climate, and by other environmental influences, but that rates are affected by geographic mobility and differential identification.Thus, variations in prevalence rates would arise in the following sets of circumstances:(i) Lower out-migration rates for MS cases