A Majorly Unique Occupational Cohort
Occupational epidemiology seeks to identify hazardous exposures in the workplace using various methods of research. The gold standard for such research is the occupational cohort study, in which workers are enrolled and followed throughout their career in an industry and beyond, if possible.
Some of the major challenges for any cohort study are selection bias and incomplete follow-up. This is indeed a poignant issue in occupational epidemiology as incomplete record keeping can make cohort enumeration difficult and workers can easily be lost when they leave employment.
An ideal occupational cohort would have several key characteristics:
1. A complete listing of all the workers who ever worked in the industry (at least during a substantially long study period);
2. Complete work-history information for each of these individuals, including hire and separation dates and time spent at various positions;
3. Complete vital-status for all members throughout the study period;
4. Extensive accrued follow-up time spanning a long period;
5. A solid and reliable exposure measure;
6. A low-cost to collect, process, and analyze the data
Seldom does something real come close to an ideal, but for once we have one: Major League Baseball (MLB).