OCCUPATIONAL RESPIRATORY DISEASE SURVEILLANCE

Coal Workers' Health Surveillance Program (CWHSP) Data Query System

 

The CWHSP is a federally mandated worker medical monitoring program for underground coal miners. Its intent is to prevent early coal workers' pneumoconiosis (CWP) from progressing to disabling disease. Eligible miners can obtain periodic chest radiographs. Miners found to have radiographic evidence of CWP are advised of this and are provided, by law, the opportunity to work in a 'low-dust' occupation in the mine. The program is operated by the National Institute for Occupational Safety and Health (NIOSH), which has maintained data from this program since its inception in 1970. The data can be queried to produce tables and maps using the interactive system below. The x-rays included in this system encompass x-rays from the Coal Workers' X-ray Surveillance Program (CWXSP), National Coal Study (also known as the National Study of Coal Workers' Pneumoconiosis), Miners' Choice Health Screening Program, and Enhanced Coal Workers' X-ray Surveillance Program. New data will be added annually, and due to the dynamic nature of data collection, which includes error correction and the addition of missing information, query system data are subject to change. Further information about the program is available on the CWHSP home page.

The query system uses the last x-ray available for an individual within the selected time period. This means that the number of x-rays for any selected time period will generally be less than the sum derived from separate queries undertaken for partial time periods included within the overall selected time period. For example, the total number of x-rays for a query of the 1970 – 79 period is less than the sum of the numbers for queries of 1970 – 74 and 1975 – 79 because, for the 1970 – 79 query, only the most recent x-ray was considered for those miners examined in both 1970 – 74 and 1975 – 79. The reason for this procedure is to ensure that findings for each individual are included only once in any selected time period.

This application generates tables of CWP prevalence (n and %), by severity categories and by cumulative severity categories, for subsets of CWHSP data defined by query-specified demographic and geographical criteria. Severity Categories are determined from an x-ray's final determination (based on multiple radiographic readings using a standardized algorithm) of the International Labour Office (ILO) large opacity category (A, B, or C) and small opacity profusion category (0, 1, 2, or 3). ILO category A, B, or C represents PMF (progressive massive fibrosis), the most severe form of CWP. ILO category 1, 2, and 3 represent CWP of lesser severities.

CWP Severity Categories:

• PMF = evidence of the most severe form of CWP.
• 1, 2, and 3 = evidence of CWP, with severity increasing from ILO category 1 to 3.
• 0 = No clear evidence of CWP

Cumulative CWP Severity Categories:

• PMF = CWP Severity Category PMF
• 3+ = CWP Severity Categories 3 and PMF
• 2+ = CWP Severity Categories 2, 3, and PMF
• 1+ = CWP Severity Categories 1, 2, 3, and PMF

Prevalence (n) with 'ax' (coalescence of small opacities) is presented with the CWP Severity Categories. Further information on how CWP is classified can be found at Chest Radiography.

Two figures are generated for each mapping query:

• A map showing the number of examined miners in the query-specified Cumulative CWP Severity Category and query-specified geographic areas
• A map showing the percentage of examined miners in the query-specified Cumulative CWP Severity Category and query-specified geographic areas

Certain restrictions have been placed on the queries to protect the privacy of individual miners. Data are not listed for any district, state, or county with less than five examined miners. County-level queries are only generated for all ages (15 and older) and all tenures (0 to 40+). Data are reported by 5-year periods (or multiples of 5) because the surveillance program runs in 5-year cycles. Data are reported by 10-year periods (or multiples of 10) when age or tenure subsets are queried at the state or district level.