Explaining urban-rural variations in health: a review of interactions between individual and environment.

In order to gain insight into the relation between health and people's environment, literature published between 1985 and 1994 was gathered from several international databases. An introduction into existing theory regarding geographic disparities is presented: geographical drift and breeder hypotheses are discussed. This is followed by a critical review focusing on interaction effects of urbanicity and individual characteristics on health. This leads to two major conclusions. First, emphasis in past research has been primarily on urban constraints rather than opportunities. Positive aspects of urban living are often insufficiently appreciated. Second, positive and negative environmental aspects have an effect on health that is often dependent on individual characteristics. The extent to which the environment exerts influence on a person's health is dependent on that person's individual characteristics. These conclusions are relevant only for further developing the breeder hypothesis, however. Large scale individual based longitudinal data should be studied in order to gain more insight into the relative importance of the geographical drift hypothesis.