Forum: what is urban health?
It is estimated that by the year 2030, two-thirds of the world population will live in large cities. During the 1990s, the Brazilian population experienced the slowest overall growth rate in the last 40 years, coupled with growing urbanization: in 1991, 75.6% of the population lived in urban areas, increasing to 81.2% in 2000. What is urban health? Clearly it is a concept (and object) under construction. As theoretical and operational references, we can cite the intense urbanization of the population associated with important intra-urban inequalities. The occurrence of health-related events is associated with the attributes of individuals residing in the "urban place", as well as with the properties of these individuals in the aggregate (that is, the urban composition). Urban health incorporates another dimension: the role of the physical and social setting of the "place" (the context) in shaping people's health. The understanding that not all determinants of health-related events can be reduced to attributes limited to the hierarchical level of individual complexity is the focus of recent debate in the field of epidemiology. A new vision and understanding of the methodological complexities and inferences related to studies and variables measured at the group, aggregate, and contextual hierarchical levels has awakened growing interest and reflection on the possible effects, for the health of individuals and populations, of constructs and variables measured at the level of contextual complexity, such as income inequality, social capital, and "neighborhood" characteristics. In this Forum, Monte-Mór discusses the historical evolution of cities according to Henri Lefèbvre: from the political city to the medieval city and finally to the current industrial city and the double process characterized by the city's implosion and explosion. This extensive urbanization is spreading beyond city limits, occupying the entire social space. Could this occupation be determinant for the reemergence (in urban areas of Brazil) of diseases traditionally viewed as "rural", such as human visceral leishmaniasis? Vlahov et al. discuss the concepts "urban health penalty", "urban sprawl", and "urban health advantage". They also pose three questions that will demand huge effort, creativity, and new thinking, and it is reasonable to contend that the answers will only be possible from a trans- and interdisciplinary perspective. Finally, Caiaffa et al. use an ecological methodology to measure the intra-urban geographic variation in various health-related events, such as asthma, dengue, adolescent pregnancy, homicide, and human visceral leishmaniasis, in the context of the municipality of Belo Horizonte, Minas Gerais, Brazil. We hope that the articles will fuel the debate and contribute to the incorporation of the urban health issue into the field of collective health, both in academic institutions and health services.
Fernando Augusto Proietti; Waleska Teixeira Caiaffa
Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil