The Canadian Forces Cancer and Mortality Study II: a longitudinal record-linkage study protocol

Military service exposes personnel to unusual situations with unclear health-related implications, and to identify both immediate and delayed risks, part of health surveillance includes examination of mortality and cancer rates that extends beyond periods of military service. The main aim of the Canadian Forces Cancer and Mortality Study II (CFCAMS II) is to describe the mortality and cancer experience of Canadian Armed Forces personnel (serving and released; about 230 000 people), with the further aim of informing health promotion and prevention programs for serving personnel and services for veterans after they leave the military.

This protocol is for a retrospective cohort study of serving and released Canadian Armed Forces personnel who enrolled on or after Jan. 1, 1976 in the Regular Force or Class C of the Reserve Force. To create our cohort, we identified record-linkage methods as the most appropriate mechanism to study mortality and cancer in those with a history of Canadian military service. Statistics Canada will link the CFCAMS II cohort file to the Canadian Vital Statistics (Mortality) and Canadian Cancer Registry databases for outcomes up to Dec. 31, 2014. The linkage will be stored in their highly secure linkage environment. Statistical analyses will be broadly divided into mortality and cancer incidence.

We will quantify mortality and cancer morbidity incidence and survival using multiple established methods, as well as age-period-cohort regression models to describe the relation between military service and mortality and cancer outcomes.

The findings will represent novel and sound evidence on the risks and protective factors of military life.