گرادیان اجتماعی در امید به زندگی:مورد خلاف اوکیناوا در ژاپن

This paper examines the social gradient theory of health and life expectancy presented by Evans and his colleagues [Evans, R.G., Barer, M.L. and Marmor, T.R. (Eds.), 1994. Why are some People Healthy and others not? The Determinants of Health of Populations. Aldine de Gruyter, New York]. They maintain that social hierarchy is the determining factor in the health of large populations largely because it promotes differences in stress or the ability to cope with stress. For example, as Japan has risen to the top ranks of the economic hierarchy of nations in the late 20th century, Japanese life expectancy improved dramatically. Evans [Evans, R.G., 1994. Introduction. In: Evans, R., Barer, M., Marmor T. (Eds.), Why are some People Healthy and others not? The Determinants of Health of Populations. Aldine de Gruyter, New York, pp. 3–26.] notes that something lies behind this rapid increase in longevity and the major change was the hierarchical position of Japan relative to the rest of the world. However, we reviewed life expectancy data within Japan and found that Okinawans traditionally rank at the top in health and life expectancy and at the bottom in socioeconomic indicators. We find that the social gradient thesis does not apply in Japan and suggest that what is more important for health are health lifestyles, especially diet and social support. More research is needed to assess the validity of the social gradient thesis if it is to be used on a cross-national basis.

Numerous studies show that health status is correlated with social status: The higher a person's socioeconomic status, the longer his or her life expectancy and, conversely, the lower the status, the less longer the life (Ross and Wu, 1995, Marmot et al., 1996 and Wilkinson, 1996). An intriguing aspect of this relationship is the gradient across social strata linked to differences in hierarchy rather than deprivation (Marmot et al., 1984, Marmot et al., 1991 and Marmot et al., 1996). Although health differentials between the upper and lower classes can be explained by wide disparities in material well-being, diet, housing, leisure-time exercise, smoking, alcohol and drug abuse and greater exposure to pollutants, infectious disease, violence and other risks — it is unlikely these factors account for the differences between the upper and the upper middle class. Both strata are relatively affluent, neither is deprived; yet, the highest strata lives longer than the next highest and so on down the social scale until the bottom of the class structure is reached.