Slower immune system aging in women versus men in the Japanese population.

BACKGROUND: Gender-related differences in humans are commonly observed in behaviour, physical activity, disease, and lifespan. However, the notion that age-related changes in the immune system differ between men and women remains controversial. To elucidate the relationship between immunological changes and lifespan, peripheral blood mononuclear cells from healthy Japanese subjects (age range: 20-90 years; N = 356) were analysed by using three-colour flow cytometry. The proliferative activities and cytokine-producing capacities of T cells in response to anti-CD3 monoclonal antibody stimulation were also assessed. RESULTS: An age-related decline in the number of T cells, certain subpopulations of T cells (including CD8+ T cells, CD4+CDRA+ T cells, and CD8+CD28+ T cells), and B cells, and in the proliferative capacity of T cells was noted. The rate of decline in these immunological parameters, except for the number of CD8+ T cells, was greater in men than in women (p < 0.05). We observed an age-related increase or increasing trend in the number of CD4+ T cells, CD4+CDRO+ T cells, and natural killer (CD56+CD16+) cells, as well as in the CD4+ T cell/CD8+ T cell ratio. The rate of increase of these immunological parameters was greater in women than in men (p < 0.05). T cell proliferation index (TCPI) was calculated from the T cell proliferative activity and the number of T cells; it showed an age-related decline that was greater in men than in women (p < 0.05). T cell immune score, which was calculated using 5 T cell parameters, also showed an age-related decline that was greater in men than in women (p < 0.05). Moreover, a trend of age-related decreases was observed in IFNγ, IL-2, IL-6, and IL-10 production, when lymphocytes were cultured with anti-CD3 monoclonal antibody stimulation. The rate of decline in IL-6 and IL-10 production was greater in men than in women (p < 0.05). CONCLUSION: Age-related changes in various immunological parameters differ between men and women. Our findings indicate that the slower rate of decline in these immunological parameters in women than that in men is consistent with the fact that women live longer than do men.

Host resistance and immune responses in advanced age.

Immunosenescence results in populating immune tissues with less functional T cells, and perhaps B cells dendritic cells, that do not function well and produce more type 2 cytokines and fewer type 1 cytokines. Impaired immunity, distinct from immunosenescence, correlates more with disease burden than chronologic age. Older adults who have chronic diseases or chronic infections are more susceptible to common infections and have poor vaccine responses. Understanding specific mechanisms and targeting interventions are dependent on research to resolve the relationship between frailty-associated impaired immunity and the role of chronic infection versus immunosenescence in developing impaired immunity.

Comorbidity is a better predictor of impaired immunity than chronological age in older adults.

OBJECTIVES: To determine whether high level of comorbidity, measured using a standardized instrument, can predict impaired immunity in older adults. SETTING: Geriatric outpatient Clinic and Nursing Home Care Unit of Veterans Affairs Greater Los Angeles Healthcare System. PARTICIPANTS: Fifteen men aged 51 to 95 with varying levels of chronic illness. MEASUREMENTS: Disease burden was measured using the Cumulative Illness Rating Scale (CIRS) and immunity using proliferation of T cells induced by phytohemagglutinin (PHA) and production of interleukin (IL)-12, a proinflammatory cytokine that promotes T helper cell-dependent immune response, and IL-10, a cytokine that inhibits T helper cell-dependent immune response, in response to mitogenic stimulation of peripheral blood mononuclear cells. RESULTS: With increasing comorbidity (increase in CIRS score) in older adults, there is a proportional decrease in immune response (decrease in T cell proliferation and IL-12 production and increase in IL-10 production in response to PHA stimulation). Neither immune response nor CIRS score was significantly correlated with chronological age in this sample of older adults with varying degrees of chronic illness. CONCLUSION: This study demonstrates that the level of comorbidity correlates with the magnitude of immune response in older adults and suggests that the CIRS could be used to determine the magnitude of impaired immunity in older adults with different specific illnesses and different levels of severity.

The frail elderly: role of dendritic cells in the susceptibility of infection.

The decline in immunity in the elderly has largely been attributed to impairment of T cell mechanisms. This seems reasonable since the thymus involutes with age, so that the number of naïve cells to respond to new foreign antigens also declines. However, little is known about how aging affects antigen-presenting cells (APC) that are responsible for the initiation and outcome of effector T cell immune responses. This review focuses on the age-related alterations of a key APC, the dendritic cell (DC). Recent findings suggest that interleukin-10, a key cytokine that can suppress cell mediated immunity and maturation of DC subsets, is elevated in the very healthy elderly. However, production of IL-12, required for the initiation of T cell immune responses, declines in frail elderly along with DC antigen presenting function. These findings suggest that shifts in IL-10 and IL-12 may not only directly influence immune response but may also alter the balance and maturation of DC subsets. Finally, study of immunologic differences between the very healthy and frail elderly may reveal important changes in DC function and regulation influenced by age and/or environment (disease, nutrition, medications, etc.).

Immune dysfunction in the elderly and its reversal by antihistamines.

The decline in immunity seen in the elderly is a significant contributor to disease burden. This decline has largely been attributed to alterations in T cell immunity and contributes to an overall increased risk and severity of infection in the elderly. A key component of T cell immunity involves antigen presentation, an event where an antigen is processed and presented to specific immune cells for destruction. This event has been found to be crucial to immune function. Recent research has focused on a key antigen presenting cell (APC), the dendritic cell (DC), and changes within its function associated with aging. DCs are considered to be the most professional APCs, and are responsible for the initiation and outcome of effector T cells and their resultant immune response. DCs capture antigens and undergo a maturation process and polarize into either type 1 dendritic cells (DC1) or type 2 dendritic cells (DC2), based upon their ability to favor a T helper1 (Th1) or T helper 2 (Th2) T cell response, respectively. Evidence suggests that in normal healthy adults, a Th1 type response predominates, and in frail elders, a Th2 response predominates. It has been proposed that this change from a predominately Th1 type to a predominate Th2 type response is a possible mechanism for age-associated immune dysfunction. In addition, recent research has focused on how histamine, an inflammatory mediator, promotes a Th2 response. Histamine has also been shown to polarize human DCs into Th2 cell-promoting effector DCs or DC2s. This has been shown to occur via interaction with the H2 receptor. Therefore, we theorize that use of an H2 selective antihistamine will reverse this polarization back to a Th1 type response and therefore improve immune function of the frail elderly.

Community-based strategies for focus group recruitment of minority veterans.

Minority recruitment is crucial to successful clinical research and associated community-based outreach programs. Reaching and retaining a diverse sample is particularly challenging when research targets not only ethnic or racial minorities but also subcultural groups such as veterans of different war periods. We describe various strategies that address the special challenges of minority recruitment through our experience engaging an ethnically diverse sample of 258 veterans as part of an evaluation of ambulatory care services at Department of Veterans Affairs health care facilities. Most veterans were recruited by liaison with the community center, which accounted for 29% of the total sample. Other strategies included on-site recruitment (21%), word of mouth (21%), mailings to veterans' organizations (12%), and newspaper advertisements (7%). Strategies varied in their effectiveness at reaching specific racial or ethnic groups and veterans from different cohorts of war service.

Racial variations in Department of Veterans Affairs ambulatory care use and unmet health care needs.

Our objective was to describe racial/ethnic variations in Department of Veterans Affairs (VA) ambulatory care use and its association with the presence of unmet health care needs. Using the 1992 National Survey of Veterans, we examined race/ethnicity and unmet health care need for ambulatory care users of VA and non-VA facilities. Black and Hispanic veterans were more likely to report any VA use. In unadjusted analyses, American Indian/Eskimo, Hispanic, and black veterans were 4.4, 2.5, and 1.9 times more likely, respectively, than white veterans to report an inability to get needed care. Adjusting for VA ambulatory care use diminished the disparity in inability to get needed care between American Indian/Eskimo or Hispanic veterans and white veterans and eliminated the disparity between black and white veterans. Our findings support the VA's role as a medical safety net provider and suggest that VA ambulatory care use is effective in mitigating health-related racial disparities for some veterans. Additional facilitators for reducing unmet need should be explored.

The influence of military service on outpatient care use among racial/ethnic groups in Department of Veterans Affairs medical centers.

This study examines race-specific military service effects on outpatient care utilization in the Department of Veterans Affairs (VA) using data from the 1992 National Survey of Veterans. The study population consisted of 4,791 male veterans. After controlling for predisposing, enabling, and need variables, black veterans were 3.7 times more likely than white veterans to use VA outpatient care. Veterans discharged from the military for medical release were less likely to use VA outpatient care (odds ratio = 0.76) than veterans discharged at the end of their normal terms. Hispanic veterans discharged for medical release were 5.3 times more likely than white veterans discharged for the same reason to use VA outpatient care. Korean conflict and mixed war period veterans were more likely to use VA outpatient care than World War II veterans. Racial/ethnic differences in military service characteristics influence the use of VA outpatient care and should be understood in delivering outpatient care to veterans.

Application of the Behavioral Model to Health Studies of Asian and Pacific Islander Americans.

PURPOSE. The purpose of this study is to review the literature to synthesize empirical health services research on Asian and Pacific Islander American (APIA) populations. Health studies of APIA are summarized using the Behavioral Model of Health Care Utilization, which has been expanded for racial and ethnic groups. METHODS. The MEDLINE databases from 1980 to 1994 were searched for all studies focusing on APIA populations using selected key words. In addition, we searched for comparative studies of APIA with other ethnic groups. Screened studies were assigned codes based on the expanded Behavioral Model using information contained in the abstracts. PRINCIPAL FINDINGS. Although the _number_ of studies that have been published on APIA populations have increased over the past 15 years, the _proportion_ of studies that focus on specific subgroups of the population has decreased. The populations that are most understudied relative to their size are Koreans and Filipinos. Most of the studies included population characteristics and evaluated/clinical outcomes, while studies of preceived and consumer satisfaction outcomes were relatively infrequent. CONCLUSIONS. Given the rapid growth of the APIA population, this group is underrepresented in the published work. Studies are needed that determine cultural influences on health status and outcomes of the health care system for ethnic subgrups of the APIA population. KEY WORDS. Asian Americans; Pacific Islanders; Behavioral Model; Asian Indian; Cambodian; Chinese; Filipino; Guamanian; Hawaiian; Hmong; Indochinese, Japanese, Koreans, Laos; Laotian; Samoan; Southeast Asian; Thai; and Vietnamese.

Development of a culturally sensitive educational intervention program to reduce the high incidence of tuberculosis among foreign-born Vietnamese.

OBJECTIVE: In Los Angeles County and Orange County, 98% of Asians with tuberculosis (TB) were foreign born; newly arrived Vietnamese immigrants had the highest TB risk: i.e. > 100 times higher than that of the USA. The study objective was to find ways to reduce the high incidence of tuberculosis among the Vietnamese by: (1) identifying and understanding the cultural health beliefs and barriers among the Vietnamese population of Orange County, California; and (2) developing a partnership between UCLA/VA/RAND MEDTEP, key Vietnamese community-based organizations, and community leaders in Orange County to develop and implement a comprehensive, culturally sensitive educational intervention program. DESIGN: Vietnamese residing in Orange County were recruited to obtain qualitative and quantitative data in 1998 and 1999, respectively. The study design included focus groups, in-depth interviews, and community surveys. Data were collected via qualitative reports, computer-assisted random telephone interviews, and self-administered questionnaires. RESULTS: A conceptual schema was identified within the Vietnamese health belief system that recognized two different forms of tuberculosis: non-infectious psychological and infectious physical tuberculosis. It was possible to engage community organizations in developing programs to combat TB in the Vietnamese population. CONCLUSION: The Health beliefs of Vietnamese will be important considerations in developing a culturally sensitive educational intervention program to service this at-risk population.

Does Acculturation Influence Physical Activity in Japanese American Older Adults?

PURPOSE: Despite the health benefits of physical activity, demographic and health factors as well as cultural backgrounds are thought to influence participation in physical activity. The aim of this study is to examine whether acculturation is associated with physical activity in a sample of Japanese American older adults living on the continental United States. METHODS: A survey was mailed to Japanese Americans identified from the mailing list of two community­based organizations. The survey included questions on physical activity, acculturation, demographics, health behaviors, and self­reported health status. Data were analyzed using bivariate and multiple regression techniques. FINDINGS: Acculturation was not a significant predictor of phsical activity in either community sample, or the pooled sample, after conrolling for other sociodemographic andhealth status variables. The models explained 23% to 2% of the variance in physical activity. Statistically significant predictors of physical activity included gender, work status, age, income, and health status. CONCLUSIONS: Our findings differ from studies of Japanese Americans in Hawaii and other racial/ethnic groups, suggesting that accultraion may have differential effects depending on the environment and the racial/ethnic group under study. KEY WORDS: Japanese American, physical activity, acculturation

Profile of Tuberculosis among Foreign-born Asians Residing in Los Angeles County, California, 1985­1994.

PURPOSE. To present a profile of tuberculosis %lpar;TB) among foreign& shy;born Asians residing in Los Angeles County and priorities in eliminating TB. SUMMARY OF METHODS UTILIZED. The demographic and disease­related data were analyzed from a total of 3,364 TB cases among Asians, which were obtained over a 9­year period (1985& shy;1994) by the Los Angeles County Tuberculosis Control Program. Various sources were used to obtain the denominators needed to calculate case rates because no one source had all the information. The data were analyzed using the standard SAS statistical software system. PRINCIPAL FINDINGS. Ninety& shy;eight percent of Asians with TB were foreign& shy;born, and 91 percent of the foreign& shy;born with TB were born in countries with high endemic rates of TB (Vietnam, Philippines, South Korea and the People's Republic of China). The TB case rate of foreign& shy;born Asians increased linearly with increase in percent household income below poverty level. The relative risk of TB among newly arrived Vietnamese, Filipinos, Chinese from People's Republic of China and Koreans was 112.0, 91.0, 36.8 and 28.1 times higher than that of the overall U.S., respectively (risk). CONCLUSIONS. The current screening procedures identify large numbers of TB cases among newly arrived Asians who contribute significantly to the occurrence of TB in Los Angeles County. Better strategies should be developed to effectively reduce morbidity in foreign& shy;born Asians from countries with high endemic rates of TB. They include the development of a comprehensive, ethnic& shy;specific, culturally sensitive educational intervention campaign and readily accessible outreach clinics with culturally sensitive TB preventive therapy program. KEY WORDS. Asians, tuberculosis, immigrants, Filipinos, Koreans, Chiense, Vietnamese.

Veteran identity and race/ethnicity: influences on VA outpatient care utilization.

BACKGROUND: "Veteran identity" is defined as veterans' self-concept that derives from his/her military experience within a sociohistorical context. Veteran identity may vary by race/ethnicity because the sociohistorical context of the military experience varies by race. OBJECTIVES: To explore veteran identity and how it varies by race/ethnicity, and to identify aspects of veteran identity that significantly influence preferences for, and use of, VA outpatient care. RESEARCH DESIGN: Focus groups were conducted at community sites to explore concepts related to veteran identity, race/ethnicity, military experience, and health services use. The focus groups informed the development of a telephone survey, which was administered to veterans of four racial/ethnic groups in Southern California and Southern Nevada. SUBJECTS: One hundred seventy-eight veterans participated in the focus groups, and 3,227 veterans completed the telephone survey. MEASURES: Dependent variables include: (1) preference for VA health services, (2) VA-only outpatient use, (3) Any VA outpatient use, and (4) number of outpatient visits within the previous 12 months. Independent variables include veteran identity, sociodemographic, and health-related characteristics. RESULTS: All veteran identity variables were significantly associated with race/ethnicity. Race/ethnicity, eg, being black or Hispanic, in addition to veteran identity factors, significantly influenced preferences for VA outpatient care. Veteran identity factors, however, had less influence on VA outpatient service utilization than socioeconomic factors. CONCLUSIONS: Minority veterans who highly identify with their veteran status may prefer the VA to other systems of care. Factors associated with veteran identity may be useful for incorporation into interventions to improve access to VA care.