Commentary for JOEM Forum-Silicosis: Then and Now

Global and national burden and trends of mortality and disability-adjusted life years for silicosis, from 1990 to 2019: results from the Global Burden of Disease study 2019

Background

Silicosis, as an important type of pneumoconiosis, leads to progressive and irreversible conditions from the beginning of inflammation and fibrosis. However, the data on the global burden of silicosis and long-term trends were limited.

Methods

Derived from the Global Burden of Disease study 2019 (online publicly available: Global Health Data Exchange), data on both crude and age-standardized rates (ASR) per 100,00 people of mortality and disability-adjusted life years (DALYs) due to silicosis was collected and analyzed. The burden and trends of mortality and DALYs due to silicosis was assessed by 204 countries and territories, by 5-year interval of age group and by sex from 1990 to 2019. And all the regions were divided into 5 categories according to Sociodemographic Index (SDI). Temporal trends in mortality and DALY were evaluated only to ASR by the Joinpoint regression model.

Results

More than 12.9 thousand [95% Uncertainty Intervals (UI): 10.9, 16.2] death cases occurred due to silicosis worldwide, and 655.7 thousand (95% UI: 519.3, 828.0) DALYs were attributed to silicosis in 2019. From 1990 to 2019, global number of mortality and DALYs in countries with high SDI quintile decreased by 0.35% (95% UI: − 0.45, − 0.17) and 0.32% (95% UI: − 0.45, − 0.01), respectively. There was a greater burden in low- and middle-income countries were estimated in 2019 according to ASRs. The global number of mortality and DALYs among males accounted for over 95% of all in 2019. Both age-sex-specific mortality and DALY rate were increasing with aging and reached their peak at 85–89 age group. During the past 30 years, ASR of mortality and DALYs showed a decreasing trend with average annual percentage change at -3.0% [95% Confidence Intervals (CI): − 3.2, − 2.9] and − 2.0 (95% CI: − 1.7, − 2.2), respectively.

Conclusions

Silicosis remains an important health issue and causes a potentially serious burden worldwide. Attention should be paid to making preventable, affordable and effective measures in lower SDI regions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02040-9.

Immunity to the Dual Threat of Silica Exposure and Mycobacterium tuberculosis

Exposure to silica and the consequent development of silicosis are well-known health problems in countries with mining and other dust producing industries. Apart from its direct fibrotic effect on lung tissue, chronic and immunomodulatory character of silica causes susceptibility to tuberculosis (TB) leading to a significantly higher TB incidence in silica-exposed populations. The presence of silica particles in the lung and silicosis may facilitate initiation of tuberculous infection and progression to active TB, and exacerbate the course and outcome of TB, including prognosis and survival. However, the exact mechanisms of the involvement of silica in the pathological processes during mycobacterial infection are not yet fully understood. In this review, we focus on the host's immunological response to both silica and Mycobacterium tuberculosis, on agents of innate and adaptive immunity, and particularly on silica-induced immunological modifications in co-exposure that influence disease pathogenesis. We review what is known about the impact of silica and Mycobacterium tuberculosis or their co-exposure on the host's immune system, especially an impact that goes beyond an exclusive focus on macrophages as the first line of the defense. In both silicosis and TB, acquired immunity plays a major role in the restriction and/or elimination of pathogenic agents. Further research is needed to determine the effects of silica in adaptive immunity and in the pathogenesis of TB.