[Tuberculosis among construction workers in dormitory housing in Chiba City]

Tuberculosis (TB) control in a low socio-economic society is an important program for urban area of industrialized countries. Some construction workers live in Hanba, a kind of dormitory housings that have crowded living conditions, and possibly give rise to Mycobacterium tuberculosis transmission. The pulmonary tuberculosis detection rate by chest X-ray screening in Hanba is higher than the general population, and therefore TB incidence among Hanba construction worker is also estimated to be as high as that of homeless.

To analyze the ratio of the TB patients from Hanba in Chiba City from 1993 through 2006, and analyze the treatment outcome and speculate the factors affecting them, especially the effects of the inpatients DOTS (Directly Observed Treatment Short-course) policy introduction after 2001.

TB registration records in the Public Health Center, Chiba City, Japan, were retrospectively analyzed.

Pulmonary TB patients from Hanba were 121 (male: 121, female: 0), representing 3.8% of the total 3179 TB patients from 1993 through 2006. Restricting to male patients aged 40-59 years-old, TB patients from Hanba were 78, representing 10.7% of 729 male TB patients of the same age groups. All of TB patients from Hanba developed pulmonary TB (PTB) and treatment outcome of chemotherapy was cured or completed: 69 (57%), defaulted or failed: 43 (36%), and died 9 (7%) respectively. When compared with PTB in Chiba and Japan, defaulted or failed was higher. In the multi-variated analysis, extensive lesions more than one lung (Adjusted odds ratio [AOR]: 0.13, 95% confidence interval [CI]: 0.04-0.37, P < 0.001) and smear-positive (AOR: 0.17, 95% CI: 0.04-0.65, P = 0.009) were negative factor for cured and completed. However, hospitalization during initial period of treatment was positive factor (AOR: 7.92, 95% CI: 1.73-36.2, P = 0.008). After inpatients DOTS introduction, the rate of cured or completed increased from 50% to 67%, and the rate of failed or defaulted decreased from 46% to 22% (P < 0.05).

TB patients from Hanba, a kind of dormitory housings for construction workers, occupied 3.8% of total TB patients in Chiba City. Higher rate of defaulted or failed cases leads to poor treatment outcome in TB patients of Hanba construction workers who were possibly associated with an elevated risk of urban tuberculosis. DOTS might improve adherence to treatment and result in a decrease of failed or defaulted cases.