Prevalence of pulmonary tuberculosis before and after soil dust in Khuzestan, southwest Iran

Background: Soil dust has been debated about its effects on public health and the challenge is brought about tuberculosis (TB). The purpose of this study was to investigate the influence of soil dust on pulmonary tuberculosis (PTB) prevalence and its control indices. Methods: The medical files of patients in Khuzestan Health Center were reviewed. The control group included the PTB patients registered from 2005 to 2006 (before soil dust), and case group consisted of PTB patients who were registered from 2007 to 2010 (after soil dust exposure). The diagnosis of tuberculosis was based on National Tuberculosis Program (NTP). Results: The mean age of control and case group was 42 (18-80) years and 40 (13-99) years, respectively. The prevalence of pulmonary TB in the control and case group was 537 (12.5 per 100000 population) and 465 (11.0 per 100000 population), respectively. Exposure to dust did not increase the prevalence of TB. The prevalence was higher in women than men (298, 41.8% vs. 336, 48.2%), in children than adult group (31, 4.3% vs. 53, 7.3%), in urban than rural inhabitants (448, 63% vs.496, 71.1%) and in family contacts than solitary contamination (60, 8.4% vs. 97, 13.9%). The rate of treatment failure, TB relapse, and MDR-TB in controls and cases were (1.4%, 1.4%, 1%) and (7%, 5.5%, 4.6%), respectively. Dust exposure had significant effect on treatment outcome. Conclusion: Although soil dust exposure had no significant effect on TB prevalence, but significantly affected the prevalence of TB respecting to age, sex, residential area and closed contact. In addition resulted in more treatment failure, development of MDR TB and relapse.