Statistics show without doubt the dramatic situation of world health, despite the right to health being proclaimed at international level. It has to be acknowledged that all the factors involved in increasing health standards are far from being clear, and that there is therefore no magic "what to do" formula. We still have a lot to learn on how to develop efficient health action. According to different studies, the critical issue could lie in the quality of the social and physical microenvironment.
Efforts to improve the population's health have been mainly channeled into welfare systems, responding to the belief that public health services are the main determining factor in health. Although the availability of health systems-or lack thereof-may be decisive in individual cases, it cannot explain all the health differences among populations.
An effective health policy needs to take into account the relative importance of various health determinants. In this area, what is important now is to reorient and refocus the social debate. This is an invitation to an international debate among professionals active in different disciplines and health professionals of all specialties from different countries with dissimilar socioeconomic realities, with a view to integrate different perspectives, experiences, and proposals on health at the start of the twenty-first century.
Challenges for health in the 21eth century 