Pulmonary tuberculosis and associated factors in areas of high levels of poverty in Chiapas, Mexico

Objectives. To estimate the prevalence of pulmonary tuberculosis (PTB) and factors associated with PTB in areas of high levels of poverty in Chiapas, Mexico. Methods. In 1998 active case-finding was carried out among those aged over 14 years who had a cough of ≥ 15 days duration, in a convenience sample of 1894 households in 32 communities selected at random based on the level of poverty and on the level of access to health services, measured by travelling time (<1 hour, ≥ 1 hour) from the community to the nearest health care unit. Of the 277 identified with a productive cough, we obtained sputum samples from 228 for the purposes of detecting PTB through acid-fast smears and cultures. Mycobacteria characterization was carried out using the BACTEC method. The identification of factors associated with PTB was performed using bivariate analysis and via logistic regression models. Results. A PTB rate of 276.9 per 100 000 persons aged ≥ 15 years was found (95% CI : 161-443). Blood in sputum was the only factor associated with PTB (none of the demographic or socioeconomic characteristics were). Of 16 positive cultures, 14 became contaminated. The two cultures characterized were Mycobacterium tuberculosis (one being multiresistant). Conclusion. The high prevalence of PTB detected indicates the need, both in the area studied and in others with similar conditions, to develop PTB control programmes which give priority to early diagnosis and to the provision of adequate treatment.