Data elements in the Canadian Forces Cancer and Mortality Study II cohort file
| Variable | Description |
|---|---|
| Demographic information | These data elements will be used by Statistics Canada to link the study cohort file to the Vital Statistics – Death Database and the Canadian Cancer Registry. Once they are linked, only date of birth and sex will be retained; name and social insurance number will be truncated, and a randomly generated unique identifier will be issued for each unique individual. |
| Name | |
| Sex | |
| Date of birth | |
| Social insurance number | |
| Occupational information | |
| Rank(s) | Initial rank and subsequent rank changes, as well as related date(s) of rank changes (promotions and demotions) will be included in the linked cohort file. Each rank change and corresponding date will be captured as their own variables. |
| Command(s) | Initial command (Regular Force or Class C Reserve Force) and subsequent command change(s), as well as related date(s) of command changes will be included in the linked cohort file. Each command change and corresponding date will be captured as their own variables. |
| Element(s) | Initial element (Army, Navy or Air Force) and subsequent element changes, as well as related date(s) of element changes will be included in the linked cohort file. Each element change and corresponding date will be captured as their own variables. |
| Enrolment date(s) | Start of a person’s employment as a military member. The first iteration of this variable will be used to ascertain whether a possible participant’s first enrolment date corresponds with the cohort’s date-related inclusion criteria. As personnel can leave and subsequently reenrol, as well as change between Regular and Reservist service, participants may have > 1 enrolment date. Each enrolment date will be captured as its own variable. |
| Release date(s) | End of person’s employment as a military member. As personnel can leave and subsequently reenrol, as well as change between Regular and Reservist service, participants may have > 1 enrolment date. However, it is possible that a person may have no release date; this means he/she was still in service at the time of study end. Each release date will be captured as its own variable. |
| Reason(s) for release | For each release date captured in the cohort file, there should be a corresponding reason for release (voluntary, involuntary, medical or unknown). In the event of multiple releases, each reason for release and its corresponding date will be captured as their own variables. |
| Occupational history | Information on participants’ military occupation (Military occupation code or Military Occupation Structure Identification code). |
| Foreign posting and deployment history | Start and stop date(s) of any international military operation. The information captured as part of this includes the operation name (if applicable), the start and stop date(s) and the location(s) of the posting/deployment. |
| Derived information | |
| Person-years of service | Variable derived with the use of enrolment and release dates to calculate cumulative person-years of service for all participants. Will also be used in analyses to control for effect of length of service on outcomes of interest. |
| Time since release | Variable derived only for participants with a terminal release date (i.e., no subsequent reenrolment date). Quantifies the time between release and death or censorship. |
| Era of service | Variable derived to control for era effects within the data. Era of service categories used elsewhere, as well as other stratifications based on salient evidence, will be evaluated for suitability and optimal statistical power. |
| Deployment — dichotomous | Dichotomizes participants into “have deployed” v. “never deployed” on international deployment. |
| Deployment — cumulative time | Variable derived by calculating a cumulative amount of time on international deployment until release, death or censorship. |
| Deployment — frequency | Variable derived by counting the number of discrete international deployments a participant will have been on until release, death or censorship. |
| Deployment — specific deployment flag | For specific deployments of interest (e.g., Afghanistan, Gulf War, Rwanda), a flag may be created to identify those who participated in specific foreign military operations. |