RESUMEN
Background: The accessibility to health centers is a limitation to the use of preventive and curative health centers. Aim: To assess geographic accessibility using a parameter that integrates information about the use ofpreventive services and travelling time froin home to the health center. Material and methods: We analyzed target geographical áreas of10 community centers located at the Northeast of México. A survey was conducted to collect information about the utilization of preventive services for detection of diabetes and hypertension within last year and in women, detection of cervical and breast cáncer. The time required to travel between the health center and the farthest location point at every neighborhood of each geographic área, using public or private transportation, was calculated. Health service use and transportation time were condensed in a single parameter, called geographic accessibility index. Data was normalized using z scores. Resulte: Three geographical areas denominated 7, 8 and 10 had the lowest detection rates of chronic diseases, with valúes rangingfrom 45 percent to 48 percent. By car, área number 3 had the longest travelling time, corresponding to 14 minutes. The longest travelling times by public transportation were detected in áreas 1 and 3, corresponding to 27 and 29 minutes, respectively The geographic accessibility index showed that the least favorable z scores travelling by car corresponded to areas 6 and 10 and, when travelling on public transportation, to áreas 8 and 10. Conclusions: The geographic accessibility index identified areas that required improvements in accessibility.