Introduction: Several databases exist in the field of occupational health, and the National Occupational Health Plan has called for a comprehensive overview of them. Four of these databases are analyzed in terms of their complementarity and overlap. Sumer examines occupational risk exposures based on the expertise of occupational physicians. Evrest studies working conditions from the employees’ perspective as well as their health. MCP identifies work-related conditions and exposures suspected of causing them. RNV3P identifies associations between exposures and conditions by assigning a causality rating based on scientific rather than medico-legal criteria. Objective: To demonstrate the complementary nature of these systems using an example involving female home health aides (FAAD). Method: Within each system, FAADs were compared with other women. Then, the results of the four systems were compared with one another. Results: The sample sizes were 425, 10,852, 797, and 463 FAADs and 10,966, 263,384, 26,245, and 11,253 other women, respectively, for Evrest, MCP, RNV3P, and Sumer. Compared to other women, FAADs are significantly older, more likely to work part-time, exposed to physical or biomechanical stressors, and more likely to have musculoskeletal disorders but not more frequent psychological distress. Finally, the RNV3P records skin or respiratory conditions, whereas these are rarely reported in MCP. Discussion: Each database provides information in its own right, but comparing the results across databases—even if they do not strictly examine the same populations—provides additional insights into the differing perspectives on occupational exposures between employees and healthcare professionals, employees’ work-related and non-work-related health issues, and the factors leading to underreporting of occupational diseases...