We currently live in an era of rapid globalization, with few societies beyond its reach. In 1950, 30% of the world's population lived in urban areas; today the proportion of urban residents is nearly 50%, and will exceed 60% by 2030 (United Nations,2001). Expansions in international trade, market economies, and formal systems of education provide opportunities for some and social inequality for many, while a global mass media fuels new consumer desires and expectations (Ger and Belk, 1996; Navarro, 1999). Populations that were once relatively isolated – geographically, linguistically, culturally – are becoming increasingly exposed to, or interfacing with, novel environments and lifestyles that may differ considerably from their own. What implications do these processes have for human biology and health? For our understanding of processes related to human adaptation?
These questions have been hotly debated by anthropologists, epidemiologists, and economists for over half a century, and simple answers are not forthcoming. Most research focuses on the health impact of recent transitions related to globalization, but it is important to recognize that human biology has been shaped by dynamic relationships with cultural, economic, and broader ecological factors since the Neolithic Revolution. For example, rises in infectious disease associated with shifts from hunting and gathering to sedentization and agricultural intensification beginning about 10 000 years ago can be considered the first epidemiologic transition (Barrett et al., 1998).