Occupational exposure and tuberculosis among medical residents in a high-burden setting: an open-cohort study.

SETTING: Postgraduate (PG) residency programme of a tertiary care teaching hospital in southern India. OBJECTIVE: To estimate the incidence of tuberculosis (TB) among PG residents, determine the frequency of exposure to infectious TB patients and assess whether particular specialties were associated with higher risk of exposure and incident TB. DESIGN: We assembled an open cohort of PG residents who were on the academic rolls for more than 3 months at any time between December 2011 and January 2013. We collected data both retrospectively and prospectively using two surveys-an entry survey at study initiation or entry into the cohort, and an exit survey at residency completion or study closure. RESULTS: Among 398 PG residents enrolled in the study, we identified five cases of incident TB during a cumulative follow-up period of 10 962 person-months. The incidence rate was 547 per 100 000 person-years, which was 3.1 times the incidence in the general population. Nearly two thirds (n = 257, 65%) of the residents were exposed to at least one infectious patient. Across the three specialty-based risk strata, there was an ordered increase in the median number of exposures (P < 0.001) and evaluation for presumptive TB (P = 0.024), as well as a trend towards higher incident TB. CONCLUSION: TB incidence is significantly higher among PG residents than in the general population.