EVALUATION OF SERUM TYPE-III PROCOLLAGEN PEPTIDE AS AN EXPOSURE MARKER IN RETIRED COAL-WORKERS

Serum type III procollagen peptide (PIIIP), a degradation product of t he type III collagen precursor, has been put forward as an exposure ma rker for mineral dust. We evaluated PIIIP levels as a marker of exposu re to and effects of coal dust in retired coal miners (n = 104). To th is end: (a) the individual cumulative dust exposure was calculated fro m job-exposure matrices, and (b) in addition to routine chest radiogra phy (CR) of all miners according to the criteria of the International Labour Organisation (ILO), a subgroup (n = 46) was screened by high-re solution computed tomography (HRCT). Profusion score (CR and HRCT) ten ded to increase with cumulative dust exposure, even in the absence of CR evidence for pneumoconiosis (i.e. CR less than or equal to 0/1, n = 35). In contrast to our previous findings in active miners, PIIIP lev els were not increased in miners as compared with non-dust-exposed con trols (n = 29), and no differences were observed between miners withou t (ILO = 0/0) and miners with coalworkers' pneumoconiosis (CWP; ILO gr eater than or equal to 0/1). No trend in PIIIP versus pneumoconiosis s tage was present, either by CR or by the more sensitive HRCT score. PI IIP was also unrelated to any lung function parameter (FEV(1), FVC, im pedance, diffusion capacity). Age, medication, medical history and smo king habits had no significant effect on PIIIP levels. In the miners w ith CWP (i.e. ILO > 0/0, n = 28) a significant negative correlation wa s present between PIIIP values and (log) cumulative dust exposure. Thi s decrease in serum PIIIP levels with increasing cumulative exposure m ay be due to chronic adaptive changes in type III collagen deposition and/or breakdown. Other relations between exposure and PIIIP were not observed. In conclusion, the present findings do not support the use o f serum type III procollagen peptide as a marker of exposure to and (e arly) interstitial or respiratory effects of coal dust.