Health risks among submarine personnel in the U.S. Navy, 1974-1979

This study evaluated health risks associated with U.S. Navy submarine duty by comparing hospitalization rates of submariners with surface ship personnel. The groups were compared using age-adjusted hospitalization rates for 16 major diagnostic categories and several specific diagnoses postulated to be submarine associated. Submarine personnel did not have significantly higher hospitalization rates for any diagnostic categories nor for any of the submarine-associated illnesses. Submariner relative risk of hospital admissions was greater for a few selected diagnoses but statistical significance was not attained. Submarine personnel had lower hospitalization rates for nearly all of the diagnostic categories examined. Reasons for these lower rates may be stringent screening of submariners, higher levels of education among submariners, difficulty of evacuation from a submarine, and the healthy-worker effect. The health status of U.S. Navy personnel does not seem to be adversely affected by submarine duty.

Psychiatric disorders among United States Marines wounded in action in Vietnam

Although the posttraumatic stress disorders of Vietnam veterans have been well documented, the psychological and environmental factors that gave rise to these and other psychiatric disorders remain to be clearly identified. The object of this study is to determine if United States Marines who were wounded in action in Vietnam were also at risk for an impatient admission with a psychiatric disorder. We also wish to examine the effect of the practice of returning psychiatric patients to duty upon completion of treatment on the relationship between combat exposure and psychiatric distress. Records of all hospital admissions for active-duty Marines for the period 1965 to 1972 were examined and personnel having a combat-related wound or injury and/or a psychiatric hospitalization were identified. Rates of first hospitalization were calculated and standardized incidence ratios were used to obtain measures of risk. Results indicated that, compared with Marines not wounded in Vietnam, Marines wounded in Vietnam were at significant risk for having a psychiatric hospitalization. Most of the psychiatric first hospitalizations occurred before being wounded in action, however, and psychiatric patients who were treated and then returned to duty had a significantly greater than expected risk of being subsequently wounded. This risk differed with respect to psychiatric diagnosis due to variations in the practice of returning psychiatric patients to duty on the basis of primary diagnosis. Variations in the probability of being returned to duty also accounted for variations in the relative risk of psychiatric first hospitalizations among wounded Marines by diagnostic category. These results cell into question the validity of using ratios of psychiatric casualties to numbers of wounded personnel as measures of the relationship between combat exposure and psychological distress.

Health and performance of Antarctic winter-over personnel: a follow-up study

The medical and service history records of enlisted Navy personnel who applied to the Operation Deep Freeze Program between 1963 and 1973 were examined to determine if incidence rates and performance criteria were significantly different between a group of winter-over personnel and a control group of enlisted personnel who were rated as acceptable by a screening team but who did not winter over. Results indicated that the overall incidence rate for the winter-over group was significantly lower than the rate for the control group. The winter-over group also had significantly fewer first hospitalizations for neoplasms, endocrine, nutritional and metabolic disorders, and diseases of the musculoskeletal system. No differences between the two groups were observed on any of the performance indices. Results suggest that wintering over in an extreme and isolated environment does not adversely affect subsequent health and performance of enlisted personnel.

Health risks among enlisted males in the U.S. Navy: race and ethnicity as correlates of disease incidence

A cross-sectional study of all Black and Caucasian enlisted males in the U.S. Navy between 1974 and 1979 was conducted to determine if there were any significant racial group differences in disease incidence. First hospitalization rates for sixteen ICDA-8 diagnostic categories and selected diagnoses were examined and compared on the basis of race, age, year hospitalized, education and occupation. Results indicated that total disease incidence among Black males has declined in the past decade, with a reduction in total first hospitalizations from 1652 per 10,000 men in 1974 to 1088 per 10,000 men in 1979. Total incidence rates for Caucasian males in the same period declined from 1347 per 10,000 men to 1100 per 10,000 men. However, Blacks were found to be at significant risk for: mental disorders; diseases of the genitourinary system; diseases of the circulatory system; diseases of the digestive system; diseases of the blood and blood-forming organs; symptoms and ill-defined conditions; supplementary classifications; and diseases of the musculoskeletal system. Caucasians had significant higher incidence rates for diseases of the skin and subcutaneous tissue, and accidents, poisonings and violence. Nevertheless, the study results indicated that the populations of Blacks and Caucasians in the Navy are not uniform with respect to disease incidence. There exist numerous subgroups within either racial group, defined on the basis of certain demographic and social characteristics, which are at risk for particular diseases. In addition, the relationship between race and disease is mediated by several factors, including genetic predisposition, socioeconomic status and cultural patterns of belief and behavior. No single factor can account for the excess risk for all diseases among all members of either racial group.