Daily contact with a patient and poor housing affordability as determinants of pulmonary tuberculosis in urban Pakistan.

OBJECTIVE:This study aimed to evaluate the factors associated with pulmonary tuberculosis (TB) among individuals aged 15years or more in urban Karachi, Pakistan. DESIGN AND SETTING:A case-control design was implemented in three major tertiary-care hospitals to select cases (n=342) with active pulmonary TB (i.e. two sputum smears positive for Mycobacterium tuberculosis with clinical and radiographic evidence of current pulmonary TB and diagnosed between August 2002 and October 2003. Selected controls (n=342) were surgery patients from the same hospitals at time of recruitment of the cases, without clinical and radiographic evidence of pulmonary TB. RESULTS:Multivariable logistic regression model showed that daily contact with a pulmonary TB patient (adjusted odds ratio [ORadj])=5.07; 95% CI: 3.31, 7.78), and poor housing affordability (i.e. rented vs. owned) (ORadj=1.59; 95% CI: 1.13, 2.26) were significantly associated with pulmonary TB status. The overall adjusted summary population attributable risk (%) for both the risk factors together was 38.7. CONCLUSION:Reaching out to underprivileged TB patients for delivery of DOTS and focused education of patients and their contacts about M. tuberculosis transmission mode may substantially minimize pulmonary TB risk in this and similar settings.