Potential and Actual Health Hazards in the Dense Urban Operational Environment: Critical Gaps and Solutions for Military Occupational Health

Cancer incidence among Canadian Veterans: A matched cohort study

INTRODUCTION

Occupational exposures related to military service may increase the risk of cancer for military Veterans, while high levels of fitness during service may decrease risk. However, few studies have compared this post-career cancer risk directly to the employed general population.

METHODS

This retrospective cohort study used linked administrative data. Canadian Armed Forces and Royal Canadian Mounted Police Veterans in Ontario, Canada were matched 1:4 on age, sex, geography, and community-level income to a group of non-Veterans most likely to have been employed during a period similar to the Veterans' military service. Cancer diagnoses were identified using the Ontario Cancer Registry.

RESULTS

During the study period, 642 of 30 576 included Veterans (2.1%) and 3408 of the 122 293 matched general population cohort (2.8%) experienced at least one cancer diagnosis. The crude rate of cancer was 153.5 per 100 000 person-years among Veterans vs. 205.9 per 100 000 person-years for the general population cohort. After adjusting for rurality and matching variables, Veterans had an 27% lower risk of developing any cancer than their matched comparators [hazard ratio = 0.73 (95% CI: 0.67-0.80)]. Among specific cancer types, the risk of lung and colorectal cancer was significantly lower for Veterans relative to the general population cohort; the risk of breast and prostate cancer was similar.

DISCUSSION

This study adds to the growing international evidence suggesting that risk of many cancers among Veterans is lower or similar to the general population. Further understanding of the complex relationships among occupational exposures, environmental factors, and lifestyle factors is needed.

Occupational Exposures and Environmental Health Hazards of Military Personnel

BACKGROUND

Military personnel are frequently exposed to environmental pollutants that can cause a variety of diseases.

METHODS

This review analyzed publications regarding epidemiological and biomonitoring studies on occupationally-exposed military personnel.

RESULTS

The exposures include sulfur mustard, organ chlorines, combustion products, fuel vapors, and ionizing and exciting radiations. Important factors to be considered are the lengths and intensities of exposures, its proximity to the sources of environmental pollutants, as well as confounding factors (cigarette smoke, diet, photo-type, healthy warrior effect, etc.). Assessment of environmental and individual exposures to pollutants is crucial, although often omitted, because soldiers have often been evaluated based on reported health problems rather than on excessive exposure to pollutants. Biomarkers of exposures and effects are tools to explore relationships between exposures and diseases in military personnel. Another observation from this review is a major problem from the lack of suitable control groups.

CONCLUSIONS

This review indicates that only studies which analyzed epidemiological and molecular biomarkers in both exposed and control groups would provide evidence-based conclusions on exposure and disease risk in military personnel.