Tracking Silicosis in New Jersey, 1979-2012

BACKGROUND:  Silicosis, a disabling and non-reversible occupational lung disease has been a significant public health problem in New Jersey (NJ) due to the many silica-using industries in the state. The NJ Department of Health (NJDOH) has conducted silicosis surveillance since 1979 and confirmed cases using the NIOSH/CDC silicosis surveillance case definition.

METHODS: Data included NJ confirmed silicosis cases identified between 1979 and 2012 from state-required reporting sources as well as death certificates and state workers compensation files. Confirmation of cases was based on a history of occupational exposure to airborne silica dust and either one or both of the following: a) chest radiograph or other imaging study interpreted as consistent with silicosis as defined in International Labour Organization Guidelines; b) pathologic findings consistent with silicosis.  

RESULTS: A total of 561 cases of silicosis were confirmed, 87% (487) through hospital or emergency department discharge data. Silicosis was rarely the primary diagnosis; rather it was concurrent with other health conditions prompting admission. Race and gender of cases overall was similar to the population at risk for exposure. Female cases are overrepresented in the pottery industry; blacks in foundries. Ethnicity data show the system is not capturing the expected number of cases of Hispanic ethnicity. Worker exposure to silica dust in historic NJ industries, such as foundries, potteries and iron mines is linked to half (281, 51.0%) of all silicosis cases. Among ongoing industries associated with exposure, leading subsectors were: stone, glass, abrasives and concrete manufacturing (62, 11%) and nonmetallic minerals mining (62, 11%). In a handful of subgroups, the number of silicosis cases increased over the three decades of surveillance. These include heavy construction and the construction trades, dental laboratory services, manufacturing of glass and concrete products, fabricated metal products, and industrial machinery. Eleven occupations accounted for 81% of cases. Leading occupations included machine operators (121, 23.7%) and laborers (96, 18.8%). Worksite visits and industry-wide interventions were representative of NJ case distribution by industry sector.

CONCLUSIONS: Surveillance of silicosis cases remains challenging due to latency of the disease and stringent case definition. Despite these impediments, NJDOH has been able to conduct interventions at worksites and in industries representative of case distribution.