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

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 effect of dustsoil on pulmonary tuberculosis (PTB) prevalence and its control indices. 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 the PTB patients who were registered from 2007 to 2010 (after soil dust occurrence) as the case group. The diagnosis of tuberculosis was based on National Tuberculosis Program (NTP). 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 control and case group was 537 (12.5 per 100000 population) and 465 (11.0 per 100000 population), respectively. The dust did not increase the prevalence of TB. More women than men (298, 41.8% vs. 336, 48.2%), more children than any other age group (31, 4.3% vs. 53, 7.3%), more urban habitants than rural settlers (448, 63% vs.496, 71.1%) and more family contacts (60, 8.4% vs. 97, 13.9%) have become ill. 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 had significant effect on treatment outcome. Although soil dust had no significant effect on TB prevalence, but showed a significant effect on age, sex, residential area and closed contact. Dust was associated with more treatment failure, development of MDR TB and relapse.