Surveillance for Silicosis Deaths Among Persons Aged 15–44 Years — United States, 1999–2015

Jacek M. Mazurek, MD, PhD; John M. Wood, MS; Patricia L. Schleiff, MS; David N. Weissman, MD

Disclosures

Morbidity and Mortality Weekly Report. 2017;66(28):747-752. 

In This Article

Abstract and Introduction

Introduction

Silicosis is usually a disease of long latency affecting mostly older workers; therefore, silicosis deaths in young adults (aged 15–44 years) suggests acute or accelerated disease.* To understand the circumstances surrounding silicosis deaths among young persons, CDC analyzed the underlying and contributing causes of death using multiple cause-of-death data (1999–2015) and industry and occupation information abstracted from death certificates (1999–2013). During 1999–2015, among 55 pneumoconiosis deaths of young adults with International Classification of Diseases, Tenth Revision (ICD-10) code J62 (pneumoconiosis due to dust containing silica),§ 38 (69%) had code J62.8 (pneumoconiosis due to other dust containing silica), and 17 (31%) had code J62.0 (pneumoconiosis due to talc dust) listed on their death certificate. Decedents whose cause of death code was J62.8 most frequently worked in the manufacturing and construction industries and production occupations where silica exposure is known to occur. Among the 17 decedents who had death certificates listing code J62.0 as cause of death, 13 had certificates with an underlying or a contributing cause of death code listed that indicated multiple drug use or drug overdose. In addition, 13 of the 17 death certificates listing code J62.0 as cause of death had information on decedent's industry and occupation; among the 13 decedents, none worked in talc exposure–associated jobs, suggesting that their talc exposure was nonoccupational. Examining detailed information on causes of death (including external causes) and industry and occupation of decedents is essential for identifying silicosis deaths associated with occupational exposures and reducing misclassification of silicosis mortality.

Various occupationally associated pulmonary diseases are linked to exposure to silica and silicates, a large class of minerals that includes talc (hydrous magnesium silicate) and other nonfibrous silicate minerals.[1] Silicosis is caused by inhaling respirable crystalline silica. Occupational exposure to airborne respirable silica particles has been associated with work in mining, quarrying, tunneling, construction, sandblasting, masonry, foundry operations, glass manufacture, ceramic and pottery production, and cement and concrete production and with work with certain materials in dental laboratories.[2] Newly emerging occupations and tasks, including fabricating and installing quartz-containing engineered stone products and extracting natural gas by hydraulic fracturing also place workers at risk for silicosis. Approximately 2.3 million workers might be exposed to respirable crystalline silica in the United States.**

Exposure to talc causes talcosis (talco-silicosis or talco-asbestosis if talc is contaminated with silica or asbestos fibers, respectively); inhalation of talc usually results from occupational exposures during talc mining and milling and during production of ceramics, pharmaceuticals, paint, paper, cosmetics, plastics, roofing, rubber, insecticides, and other products.[3] Although only 240 workers were employed in talc mining in the United States during 2015 (the number of workers exposed to talc in milling and secondary industries is unknown), 803,000 metric tons of talc were used in various products that year.†† Nonoccupational exposure to talc dust has been associated with use of cosmetic talcum powder[4] and, importantly, with illicit intravenous or inhalation administration of talc-containing legal or illegal drugs, including marijuana, methamphetamine, methadone, promethazine, cocaine, diazepam, acetaminophen, meperidine, pentazocine, oxymorphone, and heroin.[3,5–7]

To investigate silicosis deaths among young adults, ICD-10 codes for underlying and contributing causes of death from the 1999–2015 National Center for Health Statistics' multiple cause-of-death mortality data were analyzed to provide detailed information on the circumstances surrounding pneumoconiosis deaths among young adults caused by dust containing silica. Time trends were assessed using a linear regression model. Twenty-one states provided copies of actual death certificates§§ from 1999 through 2013; usual industry and occupation entries were abstracted from these certificates and were coded using the National Institute for Occupation Safety and Health's Industry and Occupation Computerized Coding System.¶¶

During 1999–2015, a total of 55 young adult decedents had ICD-10 code J62 assigned as either the underlying or a contributing cause of death, including 38 (69%) with ICD-10 subcategory J62.8 listed as the underlying (27) or a contributing (11) cause of death. The mean age of these 38 decedents was 38.6 years; most were males (95%), white (82%), non-Hispanic (74%), and born in the United States (71%) (Table 1). None of these 38 deaths involved multiple drug use or drug overdose; three (8%) had received subcutaneous silicone injections.***

Seventeen (31%) of the 55 decedents had subcategory J62.0 listed as the underlying (11) or contributing (6) cause of death. The mean age of these decedents was 37.5 years; slightly more than half (9) were male, 13 were white, 15 were non-Hispanic, and all were born in the United States. Thirteen of these 17 deaths involved multiple drug use and drug overdose.††† The number of pneumoconiosis deaths due to other dust containing silica and due to talc dust among young adults remained stable during 1999–2015 (Table 1).

To evaluate industry and occupation of decedents with a diagnosis of silicosis, CDC obtained death certificates for 47 young adult decedents reported during 1999–2013 from 21 states§§§ who had ICD-10 code J62 assigned as the underlying or contributing cause of death. Industry and occupation entries recorded on death certificates were reviewed, including 34 (97%) certificates for 35 deaths with any mention of pneumoconiosis due to other dust containing silica and all certificates for 13 deaths with any mention of pneumoconiosis due to talc dust during 1999–2013. Among the 35 decedents with a diagnosis of pneumoconiosis due to other dust containing silica, the majority were associated with working in the manufacturing (e.g., cut stone and stone product manufacturing industry) (12 [34%]) and construction (7 [20%]) industry sectors; 11 (31%) were working in production (e.g., crushing, grinding, polishing, mixing, and blending workers) occupations; five (14%) in construction and extraction occupations; and three (9%) as brickmasons and blockmasons (Table 2). These industries and occupations have well-established associations with exposure to crystalline silica.[2] Among the 13 decedents whose death certificates included any mention of pneumoconiosis due to dust containing talc, none was employed in an industry or occupation traditionally associated with exposure to talc. Ten of these 13 decedents were assigned codes indicating multiple drug use or drug overdose. Among these 10 decedents, three worked in the health care and social assistance industry (offices of dentists, ambulatory health care services, and general medical and surgical hospitals) (Table 3).

*Chronic silicosis, the most common form of silicosis, occurs after exposure to relatively low silica concentrations for >10 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.
Records included on the entity axis that reflect the placement of each condition on the certificate for each decedent (https://www.cdc.gov/nchs/data/dvs/2b_2016.pdf); each record includes codes for 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. https://webappa.cdc.gov/ords/norms-glossary.html.
§ International Classification of Diseases, Tenth Revision (ICD-10) code J62, pneumoconiosis due to dust containing silica category, is further subdivided into pneumoconiosis due to talc dust (J62.0) and pneumoconiosis due to other dust containing silica (J62.8). http://apps.who.int/classifications/icd10/browse/2016/en#/J62.
https://www.cdc.gov/niosh/topics/silica.
**https://www.osha.gov/silica/.
†† https://minerals.usgs.gov/minerals/pubs/mcs/2017/mcs2017.pdf.
§§CDC requested death certificates from 22 states for 48 young (aged 15–44 years) decedents reported for 1999–2013 who had ICD-10 code J62 (pneumoconiosis due to dust containing silica) assigned as the underlying or contributing cause of death. Among these, 47 (received from 21 states) were available for review. Seven additional deaths with code J62 assigned to cause of death among young adults were identified in the National Center for Health Statistics multiple cause-of-death data for 2014 and 2015 (when the new data became available).
¶¶Industry and occupation entries were coded using North American Industry Classification System and 2010 Standard Occupational Classification codes. https://www.cdc.gov/niosh/topics/coding/overview.html.
***Three (8%) decedents had the underlying cause of death coded as pneumoconiosis due to other dust containing silica (J62.8) and had one or more contributing causes of death coded as the following: T65.8 (toxic effect of other and unspecified substances); T80.9 (complications following infusion, transfusion, and therapeutic injection); Y56.3 (topical agents primarily affecting skin and mucous membrane and ophthalmological, otorhinolaryngological, and dental drugs); X49 (accidental poisoning by and exposure to other and unspecified chemicals and noxious substances). All three decedents received subcutaneous silicone injections.
†††Five (29%) decedents had the underlying cause of death coded as X42 (accidental poisoning by and exposure to narcotics and psychodysleptics [hallucinogens], not elsewhere classified; n = 1) or X44 (accidental poisoning by and exposure to other and unspecified drugs, medicaments and biological substances; n = 4). Eight (47%) decedents had one or more contributing causes of death coded as F19 (multiple drug use and use of other psychoactive substances, including F19.1 [harmful use] or F19.9 [unspecified mental and behavioral disorder]); T39 (poisoning by nonopioid analgesics, antipyretics and antirheumatics, including T39.8 [other nonopioid analgesics and antipyretics, not elsewhere classified]); T40 (poisoning by narcotics and psychodysleptics [hallucinogens], including T40.2 [other opioids], T40.3 [methadone], T40.6 [other and unspecified narcotics]); T42 (poisoning by antiepileptic, sedative-hypnotic and antiparkinsonism drugs), including T42.4 [benzodiazepines], T42.6 [other antiepileptic and sedative-hypnotic drugs]); or X40 (accidental poisoning by and exposure to nonopioid analgesics, antipyretics, and antirheumatics).
§§§Alabama, Arizona, Arkansas, California, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Mississippi, New Jersey, New Mexico, North Carolina, Ohio, Pennsylvania, Tennessee, Texas, and Washington.

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