[Health indicators in urban areas. Variations in function of social coherence of the geographic areas used].

The detection of health inequalities in the urban environment and their magnitude depends to a great extent on the internal social coherence of the geographical division used. Using an existing social map of Alicante which divides the city into Basic Units for Social Intervention (BUSI), we have compared the distribution of an indicator with wellknown relationship with the socio-economic level such as Low Birth Weight, using both the BUSI and the municipal districts as analysis units. The data of the newborn were obtained from the records of the Hospital of Alicante corresponding to the years 1985, 1986 and 1987, analysing the 177 Low Birth Weights of the 7,728 born within the period. Using the BUSI we found a dose-response relationship between the socio-economic level and the LBW frequency with a range varying from 86.3 to 123.2. Using the municipal districts, the range varied from 62.5 to 159.6. We conclude that, although the geographical divisions with internal social coherence are better to detect health inequalities, municipal districts can be an analysis unit of easy access and useful for describing inequalities in the cities.