tuberculosis and living conditions in salvador, brazil: a spatial analysis

OBJECTIVE: To investigate spatial tuberculosis (TB) distribution patterns and the association between living conditions and incidence of the disease in Salvador, Bahia, Brazil. METHODS: An ecological study with neighborhood as the unit of analysis. Data was collected from the Notifiable Diseases Information System (Sistema de Informação de Agravos de Notificação, SINAN) and the Brazilian Institute of Geography and Statistics (Instituto Brasileiro de Geografia e Estatística, IBGE). Rates of TB incidence were transformed and smoothed. Spatial analysis was applied to identify spatial auto-correlation and "hotspot" areas of high and low risk. The relationship between TB and living conditions was confirmed by spatial linear regression. RESULTS: The incidence of TB in Salvador displayed heterogeneous patterns, with higher rates occurring in neighborhoods with poor living conditions in 1995 - 1996. Over the study period, disease occurrence declined, particularly in less-privileged strata. In 2004 - 2005, the association between living conditions and TB was no longer observed. CONCLUSIONS: The heterogeneous spatial distribution of TB in Salvador previously reflected inequalities related to living conditions. Improvements in such conditions and health care for the less privileged may have contributed to observed changes.