Impairment in cognitive and exercise performance during prolonged antarctic residence: effect of thyroxine supplementation in the polar triiodothyronine syndrome.

Humans who work in Antarctica display deficits in cognition, disturbances in mood, increased energy requirements, a decline of thyroid hormone products, and an increase of serum TSH. We compared measurements in 12 subjects, before deployment (baseline), with 11 monthly studies during Antarctic residence (AR). After 4 months of AR (period 1), half of the subjects (T(4) group) received L-thyroxine [64 nmol.day(-)(1) (0.05 mg.day(-)(1))]; and the other half, a placebo (placebo group) for the next 7 months of AR (period 2). During period 1, there was a 12.3 +/- 5.1% (P < 0.03) decline on the matching-to-sample (M-t-S) cognitive task and an increase in depressive symptoms, compared with baseline. During the intervention in period 2, M-t-S scores for the T(4)-treated group returned to baseline values; whereas the placebo group, in contrast, showed a reduced M-t-S score (11.2 +/- 1.3%; P < 0.0003) and serum free T(4) (5.9 +/- 2.4%; P < 0.02), compared with baseline. The change in M-t-S score was correlated with the change in free T(4) (P < 0.0003) during both periods, and increases in serum TSH preceded worsening scores in depression, tension, anger, lack of vigor, and total mood disturbance (P < 0.001) during period 2. Additionally, the submaximal work rate for a fixed O(2) use decreased 22.5 +/- 4.9% in period 1 and remained below baseline in period 2 (25.2 +/- 2.3%; P < 0.005) for both groups. After 4 months of AR, the L-thyroxine supplement was associated with improved cognition, which seems related to circulating T(4). Submaximal exercise performance decrements, observed during AR, were not changed with this L-thyroxine dose.

Community patterns of psychiatric disorders after the Exxon Valdez oil spill.

OBJECTIVE: This study examined the relationship between exposure to the Exxon Valdez oil spill and subsequent cleanup efforts and the prevalence of generalized anxiety disorder, posttraumatic stress disorder (PTSD), and depressive symptoms in 13 Alaska communities. METHOD: A community survey of 599 men and women was conducted approximately 1 year after the spill occurred. Questions from the National Institute of Mental Health Diagnostic Interview Schedule were used to assess symptoms of generalized anxiety disorder and PTSD. The Center for Epidemiologic Studies Depression (CES-D) Scale was used to assess levels of depressive symptoms. RESULTS: The post-spill (i.e., 1-year) prevalence of generalized anxiety disorder and PTSD for the study communities with all degrees of exposure was 20.2% and 9.4%, respectively. The prevalence of respondents with CES-D Scale scores above 16 and 18 was 16.6% and 14.2%, respectively. When compared with the unexposed group, members of the high-exposure group were 3.6 times as likely to have generalized anxiety disorder, 2.9 times as likely to have PTSD, 1.8 times as likely to have a CES-D Scale score of 16 and above, and 2.1 times as likely to have a CES-D Scale score of 18 and above. Women exposed to this event were particularly vulnerable to these conditions, and Alaska Natives were particularly vulnerable to depressive symptoms after the oil spill. CONCLUSIONS: The results suggest that the oil spill's impact on the psychosocial environment was as significant as its impact on the physical environment. The Exxon Valdez experience suggests a number of implications for the mental health needs of disaster victims, particularly in primary care settings.

Increasing incidence of varicella hospitalizations in United States Army and Navy personnel: are today's teenagers more susceptible? Should recruits be vaccinated?

Hospital records for 10,687 United States Army and Navy adult varicella (chickenpox) admissions were reviewed. Annual hospital admission rates for varicella increased more than fourfold in the active-duty army during 1980 to 1988 and more than 18-fold among active-duty navy enlisted personnel during 1975 to 1988. Fifty-seven percent of varicella admissions occurred in the most junior military members, aged 17 to 20. More than half of the total varicella admissions occurred in personnel with less than a year of military service. Multivariate analysis of the navy data confirmed increasing time-related trends of risk, suggesting a national temporal trend of increased varicella susceptibility in US teenagers and young adults. Administering a safe and effective varicella vaccine to army and navy recruits could prevent more than 7260 hospital-bed days during the first year of use.

Circannual pattern of hypothalamic-pituitary-thyroid (HPT) function and mood during extended antarctic residence.

The seasonal variation in thyroid function and mood was examined in 10 men and two women who spent the 1997 or 1998 austral winter at McMurdo Station, Antarctica. Serum samples of TSH, free T3 and free T4 were collected each month over a 10-month period (October-August), along with responses to the Profile of Mood States (POMS) and the Center for Epidemiologic Studies - Depression (CES-D) Scale. Both TSH and mood (a summary score created from the POMS depression, anger, fatigue and confusion subscales) exhibited a circannual pattern with peaks during the months of November and July and a trough during the months of March and April. High levels of tension-anxiety and confusion were preceded by declines in free T3 and T4. However, increases in tension-anxiety and total mood disturbance also preceded a decline in free T3 levels, suggesting a feedback of mood on T3 levels. Levels of free T4 were independently associated with preceding increases in anger scores. These results support the hypothesis that the symptoms characteristic of the winter-over syndrome is a state of relative CNS hypothyroidism. This model of seasonal variation in thyroid function and mood also has implications for an understanding of potential mechanisms underlying the association between latitude and SAD or S-SAD.

Chronic illness and depressive symptoms in the elderly: a population-based study.

A cross-sectional study of the distribution of depressive symptoms and association between depressed mood and chronic illness was conducted in a geographically defined population in southern California of 1617 men and women aged 65 years and older. The prevalence of depressed mood for the total population was 5.2%. Women exhibited a significantly higher mean depressive symptom score and a prevalence rate almost twice that of men. Depressive symptoms were associated with several risk factors in both sexes, including age, self-perception of current health status, number of reported chronic diseases and medications and amount of exercise. However, the relationship between physical illness and depressive symptoms appeared to differ by sex with respect to the nature of the disease or disability and the type of medication currently used. These findings indicate that the risk of depression does not diminish with age among the elderly as other studies have suggested.

Relationship of climate, ethnicity and socioeconomic status to Kawasaki disease in San Diego County, 1994 through 1998.

BACKGROUND: Kawasaki disease (KD) is the most common cause of acquired heart disease in children in the United States. By monitoring trends in patient numbers and demographics during a 5-year period, we were able to explore the relationship between climate, ethnicity, socioeconomic status and susceptibility to KD. METHODS: We conducted active surveillance for all patients hospitalized with KD in San Diego County from 1994 through 1998. Data on seasonal variation in monthly rainfall and temperature were obtained from the US Meteorological Service. Patient sex, age, date of admission and self-reported ethnicity were identified from patient medical records. Socioeconomic status was assessed on the basis of insurance status among patients hospitalized at a single institution. RESULTS: During the 5-year period there were 169 cases of KD in San Diego County. The overall annual incidence of KD in children < 5 years of age ranged from 8.0 to 15.4/100 000. KD incidence was inversely associated with average monthly temperature (r = -0.47, P < 0.001) and positively associated with average monthly precipitation (r = -0.52, P < 0.001). Asian/Pacific Islanders < 5 years of age were 2.7 times as likely and Hispanics were one-third as likely to be hospitalized for KD than children from all other ethnic groups combined. Children with private or military insurance in all ethnic groups were more likely to have a diagnosis of KD than children with government assistance or no insurance. After controlling for insurance status, only Asian/Pacific Islanders remained at increased risk (rate ratio, 2.14) for KD relative to all other ethnic groups combined. CONCLUSION: KD is a common childhood vasculitis of unknown etiology. The skewed ethnic distribution and seasonality are consistent with the hypothesis that KD is an infectious disease that is influenced by environmental and genetic factors.

Estrogen use and depressive symptoms in postmenopausal women.

The potential antidepressant effects of estrogen replacement therapy were examined cross-sectionally in a population of 1190 women 50 years and older living in Rancho Bernardo, California. Of the total, 294 (24.7%) were currently using estrogen. Among women aged 50-59 years, those currently using noncontraceptive estrogen had a significantly higher rate of Beck Depression Inventory scores of 13 or higher than all untreated women of the same age and higher mean depressive symptom scores than women who had never used estrogen. However, after age 60, mean depressive symptom scores and rates of categorical depression increased significantly in the untreated women but not in the treated women. A similar pattern was found when depressive symptom measures of treated and untreated women were stratified by the number of years since last menstrual period. Greater depressive symptoms in currently treated versus untreated women aged 50-59 years may reflect treatment selection bias, as a higher proportion of symptomatic depressed climacteric women seek treatment. The decreased risk of depressive symptoms after age 60 may reflect a long-term benefit of estrogen replacement or the selective discontinuation of estrogen by depressed women. In this cohort, reports of hot flushes, moods, and insomnia as the reason for estrogen use fell in parallel with a decline in depressive symptoms with increasing age, suggesting that hormone replacement therapy provided relief of physical symptoms, ie, possible causes of psychological distress. Clinical trials are needed to confirm these observations and postulated explanations.

Cigarette smoking behavior and beliefs of Hispanics in California.

We examined the association between ethnicity and cigarette smoking beliefs and behavior in a 1990 random-digit dialing telephone survey of 3,164 Hispanic and 17,975 non-Hispanic white adults in California. Ethnic self-identification and native language were associated with the prevalence of current smoking in women but not in men. However, both male and female Hispanics smoked fewer cigarettes per day than their non-Hispanic counterparts. Hispanics who reported smoking in the past 12 months were more likely than non-Hispanics to have reached the action stage of cessation and to report an attempt to quit smoking. Spanish-speaking Hispanics were most likely to believe in the harmful effects of smoking, but also most likely to believe that smoking was not addictive, that they were not addicted to cigarettes, and that smoking is something everyone should try once. Cessation and prevention programs that target Hispanic populations must be especially sensitive to values and gender-specific acculturation processes that create a discrepancy between the desire to adopt the lifestyles of the dominant society and the recognition of the concomitant health-related risks.

A multisite field test of the acceptability of physical activity counseling in primary care: project PACE.

Primary health-care providers have been encouraged to counsel their patients about regular physical activity, but there are significant barriers to effective counseling. In this study a program of training and materials was tested for acceptability to providers, office staff, and patients. Primary care providers and office staff were trained to use the Physician-based Assessment and Counseling for Exercise (PACE) materials in four geographical sites in the United States. The program was tested in a variety of settings and with diverse patient populations. The acceptability of the program during a five-month study period was evaluated through structured interviews. The training was effective in preparing the providers to counsel, and the program was generally acceptable to providers, office staff, and patients. Counseling was provided in less than five minutes by 70% of providers, and most patients reported following the recommendations given. The PACE program assists providers in overcoming barriers to counseling patients about physical activity. The PACE program is potentially an important part of a national effort to enhance the adoption and maintenance of physical activity among adults.

Going to extremes: the cultural context of stress, illness and coping in Antarctica.

The question of whether the concept of adaptation remains useful in medical anthropology is examined in the context of the human experience in Antarctica. This experience is characterized by prolonged isolation, confinement, and exposure to extreme environmental conditions. Men and women who winter-over at scientific research stations often exhibit a complex of psychophysiological symptoms in response to these stressors. However, this experience also appears to provide long-term health benefits. It is argued that the psychological symptoms are themselves part of the process of coping and do not necessarily represent an inability to adapt to the extreme environment. Coping is viewed as a process of negotiation leading to a compromise between individual and group needs. The cultural systems of Antarctic research stations are both a product of this negotiation and a set of normative and pragmatic rules regulating this process. Further, this process fosters the acquisition of new strategies or resources for coping with subsequent stressful experiences.

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.

Acculturation as a risk factor for chronic disease among Cambodian refugees in the United States.

Although the concept of acculturation originated within anthropology, in recent years it has assumed a prominent role within epidemiology as a risk factor for chronic disease. However, these studies often consider acculturation in structural terms, reflected in differences between groups assumed to lie along the same continuum, all moving in the same direction toward greater acculturation to the values and behaviors of the dominant society. This paper addresses how acculturation should be conceptualized when examining it as a potential risk factor for chronic disease and how it should be measured so that it becomes both theoretically and clinically meaningful. Four case studies of Cambodian refugees of San Diego, California are used to illustrate the following: (1) the importance of integrating an acculturation-as-process perspective with an acculturation-as-structure perspective; (2) viewing acculturation as both individual and group experience of conflict and negotiation between two systems of behavior and belief; (3) measuring it longitudinally and as narrative; and (4) understanding that rather than being an inherent health risk, it may also promote health by creating access to certain forms of health care unavailable in the country of origin and by contributing to the abandonment of risky health-related behaviors and the adoption of behaviors that promote good health.

The biocultural context of social networks and depression among the elderly.

The association between the size and structure of social networks and the prevalence of depressive symptoms was examined in a population-based study of 1615 men and women age 65 years and older. Age was significantly associated with marital status, social network index quartile, and the social relationship to the primary source of support. Women and men differed with respect to current marital status, number of close friends and relatives, frequency of face-to-face contact, and participation in voluntary associations and religious institutions. Regardless of their marital status, women were also less likely than men to point to a spouse as their primary source of support. Beck Depression Inventory mean scores and rates of depressive symptoms were inversely associated with social network index and participation in voluntary associations and religious institutions for both men and women. Individuals with no primary source of support or who depended on a relative had significantly higher than expected mean scores and rates of depressive symptoms. Both social network index and social distance to primary source of support were independently associated with depression after controlling for age, sex, and number of chronic conditions. Participation in voluntary associations, social distance from primary source of support, church membership, and number of close friends were also significant independent predictors of depressive symptoms. Results indicate that depressive symptoms are inversely associated with the size of social networks. The structure of these networks, in turn, is influenced by biological factors such as age, physical disability, and mortality of network members, and by culturally-determined rules that define the individuals and institutions available for support. However, these rules appear to differ for men and women.

Depressive symptoms in overweight and obese older adults: a test of the "jolly fat" hypothesis.

The association between body weight and depressive symptoms in older adults was examined in a population-based study of 2,245 noninstitutionalized men and women aged 50 to 89 years living in Rancho Bernardo, California, U.S.A. The prevalence of Beck Depression Inventory scores > or = 13 was inversely associated with body weight in men, but not in women. Overweight and obese 50- to 69-yr-old women were more depressed than women with a body mass index below 25 kg/m2, but the difference was only marginally significant (p = 0.09). When age, health status and medication use were controlled, the odds of being depressed were 0.34 (p = 0.004) in overweight men and 0.28 (p = 0.09) in obese men, compared to men with a body mass index below 25 kg/m2. In this cohort, depression in men was inversely associated with body weight, supporting the "Jolly Fat" hypothesis. The likelihood that more stigma is attached to excessive weight in women than men may account for the lack of an inverse association between weight and depression in women.

Suicides in active-duty enlisted Navy personnel.

Cases of completed suicide among U.S. Navy enlisted personnel occurring from 1974 through 1985 were identified and compared with similar rates in the U.S. general population and in the U.S. Army. Although the Navy suicide rate was the lowest of the three groups, this rate increased between 1976 and 1983. This was in contrast to national and Army trends during the same period. Young white males in the apprentice/recruit and blue-collar occupations had the highest rates of completed suicide in the Navy. Recommendations for prevention and treatment are discussed.

Sociocultural change and health status among the Seri Indians of Sonora, Mexico.

The influence of changes in sociocultural status on obesity, arterial blood pressure, and depression was examined in a cohort of 81 Seri Indians living in two communities in Sonora, Mexico. Residents of the less acculturated and modernized community, Desemboque, exhibited significantly higher waist circumference and prevalence of obesity than did residents of the more acculturated and modernized community of Punta Chueca. The prevalence of obesity was also significantly associated with low levels of acculturation and modernization, while the prevalence of clinically significant depressive symptoms was associated with low levels of modernization and household income. Lifestyle incongruity was a significant independent risk factor for body mass index and depressive symptom scores but not for arterial blood pressure. The results support the notion of a curvilinear relationship between health status and sociocultural change in which health status initially declines with increasing lifestyle incongruity but eventually improves with increasing acculturation, modernization, and income.

Psychosocial issues in long-term space flight: overview.

Anecdotal evidence of the individual and interpersonal problems that occurred during the Shuttle-Mir Space Program (SMSP) and other long-duration Russian/Soviet missions, and studies of personnel in other isolated and confined extreme (ICE) environments suggest that psychosocial elements of behavior and performance are likely to have a significant impact on the outcome of long-duration missions in space. This impact may range from individual decrements in performance, health and well being, to catastrophic mission failure. This paper reviews our current understanding of the psychosocial issues related to long duration space missions according to three different domains of behavior: the individual domain, the interpersonal domain and the organizational domain. Individual issues include: personality characteristics that predict successful performance, stress due to isolation and confinement and its effect on emotions and cognitive performance, adaptive and maladaptive coping styles and strategies, and requirements for the psychological support of astronauts and their families during the mission. Interpersonal issues include: impact of crew diversity and leadership styles on small group dynamics, adaptive and maladaptive features of ground-crew interactions, and processes of crew cohesion, tension and conflict. Organizational issues include: the influence of organizational culture and mission duration on individual and group performance, and managerial requirements for long duration missions. Improved screening and selection of astronaut candidates, leadership, coping and interpersonal skills training of personnel, and organizational change are key elements in the prevention of performance decrements on long-duration missions.

A longitudinal study of disease incidence among Antarctic winter-over personnel.

A longitudinal perspective was employed to test the hypothesis that there is an increased risk of hospitalization among Antarctic winter-over personnel during the first year subsequent to this duty. Subjects were 327 enlisted Navy men who wintered-over between 1963 and 1974 and a control group of 2,396 enlisted men who volunteered and were accepted for winter-over duty but who did not winter-over. A 15-year period from 1965 to 1979 was established for follow-up. Follow-up of subjects subsequent to screening for Operation Deep Freeze was conducted in 6-month intervals for the first 4 years. Results indicated that the total rates of first hospitalization during the 6 months prior to Antarctic duty and the first 6 months in Antarctica among winter-over personnel were significantly lower than the rates for the control group. No significant difference in the rates of the two groups was observed for the 12 months subsequent to winter-over duty.

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.

Summary of research issues in behavior and performance in isolated and confined extreme (ICE) environments.

The papers in this section of the workshop describe behavioral and performance charges in isolated and confined extreme (ICE) environments. These changes include increased disturbances of mood, rates of psychiatric disorder, and interpersonal tension, and a disruption of circadian rhythms. The workshop ended with four specific recommendations for future research.