CDC Releases Updated Mortality Data on Silicosis
Silicosis is a potentially fatal but preventable occupational lung disease caused by inhaling respirable crystalline silica. Chronic silicosis, the most common form, occurs after exposure to relatively low silica concentrations for more than10 years. Accelerated silicosis occurs after 5–10 years of exposure to higher silica levels, and acute silicosis can occur after only weeks or months of exposure to extremely high silica concentrations.
New national mortality data for silicosis have become available since a previous report on silicosis surveillance was published earlier this year. CDC reviewed multiple cause-of-death mortality files from the National Center for Health Statistics to analyze deaths from silicosis reported during 1999–2013. Each record lists one underlying cause of death (the disease or injury that initiated the chain of events that led directly and inevitably to death) and up to 20 contributing causes of death (other significant conditions contributing to death but not resulting in underlying cause).
Available death certificates from 35 states were reviewed for the period 2004–2006 to identify occupations associated with silicosis among decedents aged 15–44 years. Results indicate that, despite substantial progress in eliminating silicosis, silicosis deaths continue to occur. Of particular concern are silicosis deaths in young adults (aged 15–44 years). These young deaths likely reflect higher exposures than those causing chronic silicosis mortality in older people, some of sufficient magnitude to cause severe disease and death after relatively short periods of exposure. A total of 12 such deaths occurred during 2011–2013, with nine that had silicosis listed as the underlying cause of death.
During 1999–2013, a total of 2,065 decedents had silicosis listed as the underlying or as a contributing cause of death. The annual number of silicosis deaths declined 40% from 185 in 1999 to 111 in 2013, but the decline appears to have leveled off during 2010–2013. The lowest number of silicosis deaths (88) occurred in 2011. Higher numbers of deaths occurred in 2012 (103) and 2013 (111), but remained within the 95% confidence interval predicted by the first-order autoregressive linear regression model used to evaluate trends for 1999–2013. Among all silicosis deaths, 47 (2.3%) decedents were aged 15–44 years; of these, 34 (72.3%) had silicosis coded as the underlying cause of death. The annual number of silicosis deaths in persons aged 15–44 years varied and was 4, 0, and 8 in 2011, 2012, and 2013, respectively.