Descriptive analysis and comparison of two French occupational exposure databases: COLCHIC and SCOLA

Several countries have built databases of occupational hygiene measurements. In France, COLCHIC and SCOLA co-exist, started in 1987 and 2007 respectively.
Methods
A descriptive comparison of the content of the two databases was carried out during the period 1987-2012, including variables, workplaces and agents, as well as exposure levels.
Results
COLCHIC and SCOLA contain respectively 841,682 (670 chemicals) and 152,486 records (70). They cover similar industries and occupations, and contain the same ancillary information. Across 17 common agents with >500 samples, the ratio of the median concentration in COLCHIC to the median concentration in SCOLA was 3.45 [1.03-14.3] during 2007-2012. This pattern remained when stratified by industry, task, and occupation, but was attenuated when restricted to similar sampling duration.
Conclusions
COLCHIC and SCOLA represent a considerable source of information, but result from different purposes (prevention, regulatory). Potential differences due to strategies should evaluated when interpreting data from these databases.