Health Aspects of the Pre-Departure Phase of Migration

The flow of populations within and across international boundaries is an important element in today’s globalized world. Recent estimates of migration patterns place the combined numbers of international migrants and internal migrants at nearly a billion people [1]. Although migrant populations are extremely diverse, the processes of migration include certain characteristics shared by all migrants. All migrants have a place of origin. Experiences and exposures at a place of origin can influence migrants’ health throughout the process of mobility [2], which may include transition, temporary residence, and arrival at a destination. After arrival or settlement, some migrant cohorts may experience ongoing or return migrations that can also have health consequences. [3] As indicated in Table 1, rates of departure from origin countries are markedly different between global areas and countries, with rates in Europe, Latin America, and Oceania more than double those of Africa, Asia, and North America [4]. It is important to note, however, that even low rates of departure from highly populated countries of origin can produce large health impacts at destinations. In general, most migrants move to destination countries in the same region. A recent Organisation for Economic Cooperation and Development (OECD) analysis involving 89 reception countries [4] noted intra-regional emigration flows of 85% in Africa, 75% in Asia, 62% in Latin America, and 60% in Europe. Two other smaller patterns are observed, however, in situations where historical links (e.g., Latin America–Europe) to other regions exist, or where long-standing immigration settlement policies (e.g., Australia, Canada, United States) affect origin and destination dynamics. Global studies of emigration reveal a relative gender balance in aggregate migrant population. However, there are large differences at the continental, regional, and country level (see Figure 1). The same OECD database study indicates that women make up greater proportions of North American and European migrants, while they represent lower proportions of African migrants, especially those from North Africa.