Silent epidemic of silicotuberculosis in India and emergence of multidrug-resistant tuberculosis?

Abstract

Objectives

India's projected silica-dust-exposed workers will be 52 million at the end of 2025. The elimination of tuberculosis (TB) is also targeted in India by 2025. Scientists in India have already pointed out that unless silicosis is controlled, the said elimination will be difficult to achieve.

Methods and Results

This study provides evidence of an increasing incidence of tuberculosis (TB) including multidrug-resistant TB (MDR-TB) with mortality owing to treatment failure among the silica dust-exposed workers compared to their unexposed counterpart. It was also observed that TB as well as MDR-TB were directly proportional to the dose and/or duration of silica dust exposure (progression of silica-dust induced lung damage). This means the occurrence of both TB and MDR-TB is lowest in the unexposed group, moderate in the radiologically negative but silica dust-exposed group (subradiological silicosis owing to moderate exposure), and highest in the radiologically confirmed silicotic workers (maximally exposed group). Because India has a huge burden of silicosis cases, the said cases are vulnerable to pulmonary TB, including MDR-TB. The study indicates there will be an emergence of MDR-TB among the silica dust-exposed workers unless appropriate intervention measures are initiated with immediate effect. Failure to do so, it will probably lead to a silent epidemic of silicotuberculosis in India shortly.

Conclusions

It is important to have tools to detect silicosis cases quickly and at an early stage to identify a vulnerable population and adopt an effective intervention measure.