[Design and validation of a job-exposure matrix to silica].
OBJECTIVE
To develop a population-based matrix of job-exposure to crystalline silica in Brazil and to estimate its validity.


METHODS
An epidemiologist and an industrial hygienist developed a matrix of job-exposure in four stages: coding of occupation variable; coding of industry variable; consensual exposure classification between researchers; and estimate of registered workforce in 1995 for each level of exposure. The cross-tabulation of the variables industry (25 columns) and occupation (347 lines) resulted in 8,675 cells, classified according to silica exposure in four levels: non-exposed, possibly exposed, probably exposed, and definitively exposed. For validating the job-exposure matrix, five industries (mining and quarrying, construction, foundry, management of technical personal and textiles), were re-coded according to exposure by external experts. Reliability of the study and external experts was evaluated by agreement measured using kappa analysis.


RESULTS
The job-exposure matrix showed high coding agreement, ranging from 64.0% for foundry to 94.0% for mining. Kappa analysis showed good agreement in mining (0.9), and low or average for other sectors (ranging from 0.1 to 0.5). High specificity was found in foundry (86.5%) and mining (100.0%). Construction had 56% specificity.


CONCLUSIONS
The study job-exposure matrix showed good accuracy and seems to be appropriate for estimating silica exposure among Brazilian workers.
Neto Ribeiro
Fátima Sueli
FS
Area de Vigilância do Câncer Ocupacional, Coordenação de Prevenção e Vigilância, Institutuo Nacional do Câncer, Rua dos Invalides 212, 2o andar, 20231-020 Rio de Janeiro, RJ, Brazil. fatsue@inca.gov.br
de Camargo
Esther Archer
EA
Wünsch Filho
Victor
V
D000395:Air Pollutants, Occupational; D001938:Brazil; D006801:Humans; D016273:Occupational Exposure / Q000145:classification*; D015203:Reproducibility of Results; D018570:Risk Assessment; D012822:Silicon Dioxide
D000395:Air Pollutants, Occupational; D012822:Silicon Dioxide