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Biomedical subjects

D N Cowan

Publications and source records attributed to D N Cowan.

At least 19 recordsLinked to original sources
PubMed1994

The incidence of HIV infection among men in the United States Army Reserve Components, 1985-1991.

OBJECTIVE: To evaluate the incidence of HIV infection among men in the Army Reserve Components (RC) in the United States. METHODS: A prospective follow-up evaluating HIV seroconversions among men in the RC. Men who were initially seronegative were followed over time and periodically retested. The duration of follow-up was measured for each individual. Date of seroconversion was estimated to be the mid-point between last negative and first positive test. Demographic characteristics were evaluated for association with seroconversion, and incidence density between 1985 and 1991 was examined. RESULTS: We followed 733,622 RC men for 1,988,622 person-years between 1985 and 1991, and identified 534 seroconversions. Demographic correlates of risk included racial/ethnic minorities, age between 20 and 34 years, never having married, residence in an area with a low median income, and residence in metropolitan areas with high incidence of AIDS. Among most of these groups, the incidence density did not change substantially or significantly from the period 1985-1987 to 1991. CONCLUSIONS: The patterns of HIV infection are generally similar to those for reported AIDS cases. The incidence density over time is consistent with projections that AIDS incidence will plateau in the United States in the mid- to late-1990s.

Adolescent↗
PubMed1994

Consistency of visual assessments of arch height among clinicians.

Flat feet and high-arched feet have been cited as risk factors for musculoskeletal injury and functional problems among runners and other active individuals, although there are no established quantitative definitions or measures for assessing either condition. As part of a larger study, four-plane photographs were made of the weight-bearing right foot of 246 young male Army trainees. These photographs were independently evaluated by six clinicians and rated on a scale of clearly flat-footed (category 1) to clearly high arched (category 5). There was much interclinician variability in the assessments, even for extremes of foot type. The probability of a clinician assessing a foot as clearly flat, given that another clinician had rated the foot as clearly flat, ranged from 0.32 to 0.79, with a median probability of 0.57, while for clearly high-arched feet, probabilities ranged from 0.0 to 1.00, with a median of 0.17. These findings demonstrate the need for objective standards and quantitative methods of evaluating foot morphology.

Flatfoot↗
PubMed1994

Exercise, training and injuries.

Although exercise results in a number of well documented physical fitness and health benefits, accruing such benefits entails a risk of exercise-related injuries. Musculoskeletal injuries occur frequently among fitness programme participants, runners, athletes, military recruits and others who engage in routine vigorous exercise. The same parameters of exercise (intensity, duration and frequency) that determine the positive fitness and health effects of physical training also appear to influence the risk of injuries. Studies of runners and other physically active groups have consistently demonstrated that greater duration and frequency of exercise are associated with higher risks of injury. However, the sports medicine literature shows little association between exercise intensity and injuries, a finding which may be misleading. The strongest and most consistent association reported exists between greater total amounts of exercise and higher risks of injury. This is not surprising, since the total amount of exercise is the product of the intensity, duration and frequency of exercise. Recent military research confirms the finding that higher volumes of running are associated with higher rates of injury. Furthermore, the study of army recruits suggests that greater amounts of exercise not only result in greater risks of injury, but in some instances may also impart no additional increase in fitness, a finding consistent with an earlier study of civilian runners. Several military studies also demonstrate that those recruits who have been more physically active in the past are less likely to be injured during basic training. These military studies also document a number of other factors, such as older age, smoking, sedentary jobs and lifestyle, high or low flexibility and high arches of the feet, which may contribute to or modify the risks for exercise-related injuries. In conclusion, the present review suggest that, for activities such as running, specific parameters of exercise may contribute to the overall risk of injuries in rough proportion to their contribution to the total amount of activity performed. Also, better knowledge of the effects of the parameters of training and other factors on the risks of exercise-related injuries is necessary to make more judicious choices about how to best achieve the benefits of exercise and to prevent injuries.

Athletic Injuries↗
PubMed1994

HIV infection among women in the Army Reserve Components.

There is little information regarding the extent of HIV infection among women. Since late 1985, members of the Army Reserve Components have been routinely tested for HIV, providing an opportunity to measure directly the prevalence and incidence density of infection in a military-associated population with limited military contact. We evaluated the prevalence among 122,195 women, and directly measured the incidence density among 96,001 women followed for 247,872 person-years. The overall prevalence was 0.65 (per 1000), and the incidence density was 0.12 (per 1000 person years follow-up). Several demographically defined groups, including minority women, had elevated levels of infection. The incidence densities of infection between early and late in the testing program were compared, and no evidence of acceleration or deceleration was observed.

Adolescent↗
PubMed1993

Foot morphologic characteristics and risk of exercise-related injury.

OBJECTIVE: It is widely accepted that persons with flat or high-arched feet are at increased risk of exercise-associated injury, even though this purported association has not been scientifically evaluated. We evaluate the risk of exercise-associated injury among young men with flat, normal, and high-arched feet. DESIGN: A prospective study of 246 US Army Infantry trainees followed up over a rigorous 12-week training program. All subjects were evaluated prior to onset of training. Evaluation included photographs of the right, weight-bearing foot that were digitized and utilized to make several measures of arch height. SETTING: An army initial entry training center. SUBJECTS: All trainees beginning army training on 2 successive weeks were potential volunteers. There were no criteria for exclusion other than declining to participate (n = 3). The subjects were healthy, active young men with a mean age of 20.3 years. OUTCOME MEASURE: The occurrence of a lower-extremity musculoskeletal injury resulting in a visit to and a diagnosis by an army physician or physician assistant. Treating physicians and physician assistants were blind to participation status and were not study staff members. RESULTS: On univariate analysis, there was an association between arch height and risk of injury using several alternative operational definitions of foot type. The 20% with the flattest feet were at the lowest risk (reference group; odds ratio, 1.0), with adjusted odds ratios for any musculoskeletal injury of 3.0 (P < .05) for the middle 60% group and 6.1 (P < .05) for the highest 20% group. CONCLUSIONS: These findings do not support the hypothesis that low-arched individuals are at increased risk of injury, and they have implications for runners, exercise enthusiasts, and clinicians. It may be possible to prevent substantial morbidity among active populations by identifying individuals at high risk and advising alternate activities.

Adolescent↗
PubMed1993

Epidemiology of injuries associated with physical training among young men in the army.

It is widely acknowledged that musculoskeletal injuries occur as a result of vigorous physical activity and exercise, but little quantitative documentation exists on the incidence of or risk factors for these injuries. This study was conducted to assess the incidence, types, and risk factors for training-related injuries among young men undergoing Army infantry basic training. Prior to training we evaluated 303 men (median age 19 yr), utilizing questionnaires and measurements of physical fitness. Subjects were followed over 12 wk of training. Physical training was documented on a daily basis, and injuries were ascertained by review of medical records for every trainee. We performed univariate and multivariate analyses of the data. Cumulative incidence of subjects with one or more lower extremity training-related injury was 37% (80% of all injuries). The most common injuries were muscle strains, sprains, and overuse knee conditions. A number of risk factors were identified, including: older age, smoking, previous injury (sprained ankles), low levels of previous occupational and physical activity, low frequency of running before entry into the Army, flexibility (both high and low), low physical fitness on entry, and unit training (high running mileage).

Adult↗
PubMed1992

A brief review of the epidemiology of HIV in the U.S. Army.

The Department of Defense has conducted extensive HIV testing for over 5 years. We summarize the epidemiology of the HIV infection in the total Army. While screening of civilian applicants effectively ensures seronegativity of enlistees, there are approximately 220 new HIV infections each year among active duty soldiers. High-risk demographic groups in the Army include single soldiers, males, those age 25-35, blacks, and Hispanics (including black and Hispanic females). While preventive efforts in the Army should reflect the higher risk experienced by these groups, all soldiers should be made aware of their susceptibility as the epidemic evolves to include more women and heterosexual men.

AIDS Serodiagnosis↗
PubMed1991

HIV infection among members of the US Army Reserve Components with medical and health occupations.

Over 58,000 members of the US Army Reserve Components tested for human immunodeficiency virus (HIV) antibody had military or civilian medical occupations. The availability of HIV status and occupational information permits the assessment of prevalence and incidence of infection in this population. Levels of infection were not higher among women or among currently married men with medical occupations compared with those with nonmedical occupations. Prevalence and incidence were elevated among never-married men with either military or civilian medical occupations compared with never-married men with nonmedical occupations. Based on reported civilian occupation, male registered nurses and men with other medical occupations, excluding physicians and dentists, had a significantly higher prevalence of infection than men with nonmedical occupations. The patterns of infection suggest that the higher levels of infection found among never-married men with medical occupations may not be entirely due to occupational exposure. These findings may have applications in the design and interpretation of results of health care worker HIV surveillance programs.

Dentists↗
PubMed1991

Hemangiopericytoma of the central nervous system: a review of 94 cases.

Ninety-four cases of central nervous system hemangiopericytoma (CNS-HPC) are reported. Hemangiopericytoma was found more commonly in men than in women. The mean age at diagnosis was 40.9 years for men and 47 years for women. The tumor was found throughout the entire CNS, usually superficially and closely related to the meninges. Based on multiple histologic variables, the original tumors were divided into differentiated (n = 67) and anaplastic (n = 27). Anaplastic HPC was characterized by the presence of necrosis and/or greater than five mitoses per ten 400x microscopic fields, and at least two of the following microscopic features: hemorrhage, moderate to high nuclear atypia, and moderate to high cellularity. For those patients known to be dead, median survival time was 144 months for differentiated HPC and 62 months for anaplastic HPC. Fifty-seven (60.6%) patients had one or more recurrences and metastasis developed in 22 (23.4%). Thirty-five of 56 patients with differentiated HPC had recurrence, while 22 of 26 patients with anaplastic HPC had recurrence. Bone, liver, lung, central nervous system, and abdominal cavity were the most common sites of metastasis. Postoperative radiotherapy and/or chemotherapy were significantly associated with increased patient survival time.

Adolescent↗
PubMed1991

HIV infection among members of the Army Reserve components residing in New York City.

A total of 10,722 members of the US Army Reserve and Army National Guard residing within the five boroughs of New York City (NYC) were tested for antibody to human immunodeficiency virus (HIV). The crude prevalence in NYC was found to be 10.6 per 1,000, compared with a national prevalence of 1.6 per 1,000. The highest prevalences were found among Blacks and Hispanics, males, and among those aged 30-39 years. Patterns of infection were found to be similar to those found among heterosexual and drug abusing populations. Prevalence was highest in the Bronx and varied by less than twofold over all boroughs. Comparisons with reported cases of acquired immunodeficiency syndrome (AIDS) in New York City indicated differences in the demographic and geographic characteristics of the current epidemic of AIDS and HIV infection among members of the Army Reserve components.

Adult↗
PubMed1990

Human immunodeficiency virus infection among members of the reserve components of the US Army: prevalence, incidence, and demographic characteristics. The Walter Reed Retrovirus Research Group.

Since routine testing began, 677,463 members of the Reserve Components of the US Army have been tested for antibody to human immunodeficiency virus (HIV). Of these, 1063 were positive, for a crude prevalence of 1.57/1000 tested. Prevalence varied greatly among different groups as defined by sex, ethnicity, marital status, age, and geographic location. Multivariate analysis indicated that prevalence was higher among men, blacks, and unmarried men and peaked at ages 30-34. The crude incidence density was 0.20/1000 person-years, and multivariate analysis of incidence revealed patterns similar to those for prevalence. Comparison of prevalence and incidence data provides evidence that an increasing proportion of infection is occurring among women and in nonmetropolitan and small urban areas.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Behavioral risk factors for HIV infection among homosexual men at a Boston community health center.

Social and behavioral factors associated with human immunodeficiency virus (HIV) infection were analyzed using cross-sectional data from homosexual and bisexual male clients of a Boston community health center. Partners from California, and a previous period of greater sexual activity (a "high period"), were independently associated with positive HIV antibody status, as were the frequency of receptive anogenital contact, both during the "high period" and during the last six months.

Acquired Immunodeficiency Syndrome↗