Cancer mortality in a population-based cohort of American Indians - The strong heart study

BACKGROUND

Cancer mortality among American Indian (AI) people varies widely, but factors associated with cancer mortality are infrequently assessed.

METHODS

Cancer deaths were identified from death certificate data for 3516 participants of the Strong Heart Study, a population-based cohort study of AI adults ages 45-74 years in Arizona, Oklahoma, and North and South Dakota. Cancer mortality was calculated by age, sex and region. Cox proportional hazards model was used to assess independent associations between baseline factors in 1989 and cancer death by 2010.

RESULTS

After a median follow-up of 15.3 years, the cancer death rate per 1000 person-years was 6.33 (95 % CI 5.67-7.04). Cancer mortality was highest among men in North/South Dakota (8.18; 95 % CI 6.46-10.23) and lowest among women in Arizona (4.57; 95 % CI 2.87-6.92). Factors independently associated with increased cancer mortality included age, current or former smoking, waist circumference, albuminuria, urinary cadmium, and prior cancer history. Factors associated with decreased cancer mortality included Oklahoma compared to Dakota residence, higher body mass index and total cholesterol. Sex was not associated with cancer mortality. Lung cancer was the leading cause of cancer mortality overall (1.56/1000 person-years), but no lung cancer deaths occurred among Arizona participants. Mortality from unspecified cancer was relatively high (0.48/100 person-years; 95 % CI 0.32-0.71).

CONCLUSIONS

Regional variation in AI cancer mortality persisted despite adjustment for individual risk factors. Mortality from unspecified cancer was high. Better understanding of regional differences in cancer mortality, and better classification of cancer deaths, will help healthcare programs address cancer in AI communities.

Association of diabetes and cancer mortality in American Indians: the Strong Heart Study

PURPOSE

The metabolic abnormalities that accompany diabetes mellitus are associated with an increased risk of many cancers. These associations, however, have not been well studied in American Indian populations, which experience a high prevalence of diabetes. The Strong Heart Study is a population-based, prospective cohort study with extensive characterization of diabetes status.

METHODS

Among a total cohort of 4,419 participants who were followed for up to 20 years, 430 cancer deaths were identified.

RESULTS

After adjusting for sex, age, education, smoking status, drinking status, and body mass index, participants with diabetes at baseline showed an increased risk of gastric (HR 4.09; 95% CI 1.42-11.79), hepatocellular (HR 2.94; 95% CI 1.17-7.40), and prostate cancer mortality (HR 3.10; 95% CI 1.22-7.94). Further adjustment for arsenic exposure showed a significantly increased risk of all-cause cancer mortality with diabetes (HR 1.27; 95% CI 1.03-1.58). Insulin resistance among participants without diabetes at baseline was associated with hepatocellular cancer mortality (HR 4.70; 95% CI 1.55-14.26).

CONCLUSIONS

Diabetes mellitus, and/or insulin resistance among those without diabetes, is a risk factor for gastric, hepatocellular, and prostate cancer in these American Indian communities, although relatively small sample size suggests cautious interpretation. Additional research is needed to evaluate the role of diabetes and obesity on cancer incidence in American Indian communities as well as the importance of diabetes prevention and control in reducing the burden of cancer incidence and mortality in the study population.

Lung function and heart disease in American Indian adults with high frequency of metabolic abnormalities (from the Strong Heart Study)

The associations of pulmonary function with cardiovascular disease (CVD) independent of diabetes mellitus (DM) and metabolic syndrome have not been examined in a population-based setting. We examined prevalence and incidence CVD in relation to lower pulmonary function in the Strong Heart Study second examination (1993 to 1995) in 352 CVD and 2,873 non-CVD adults free of overt lung disease (mean age 60 years). Lung function was assessed by standard spirometry. Participants with metabolic syndrome or DM with or without CVD had lower pulmonary function than participants without these conditions after adjustment for hypertension, age, gender, abdominal obesity, smoking, physical activity index, and study field center. CVD participants with DM had significantly lower forced vital capacity than participants with CVD alone. Significant associations were observed between reduced pulmonary function, preclinical CVD, and prevalent CVD after adjustment for multiple CVD risk factors. During follow-up (median 13.3 years), pulmonary function did not predict CVD incidence, it predicted CVD mortality. Among 3,225 participants, 412 (298 without baseline CVD) died from CVD by the end of 2008. In models adjusted for multiple CVD risk factors, DM, metabolic syndrome, and baseline CVD, compared with highest quartile of lung function, lower lung function predicted CVD mortality (relative risk up to 1.5, 95% confidence interval 1.1 to 2.0, p<0.05). In conclusion, a population with a high prevalence of DM and metabolic syndrome and lower lung function was independently associated with prevalent clinical and preclinical CVD, and its impairment predicted CVD mortality. Additional research is needed to identify mechanisms linking metabolic abnormalities, low lung function, and CVD.

The public health foundation of health services for American Indians & Alaska Natives

The integration of public health practices with federal health care for American Indians and Alaska Natives (AI/ANs) largely derives from three major factors: the sovereign nature of AI/AN tribes, the sociocultural characteristics exhibited by the tribes, and that AI/ANs are distinct populations residing in defined geographic areas. The earliest services consisted of smallpox vaccination to a few AI/AN groups, a purely public health endeavor. Later, emphasis on public health was codified in the Snyder Act of 1921, which provided for, among other things, conservation of the health of AI/AN persons. Attention to the community was greatly expanded with the 1955 transfer of the Indian Health Service from the US Department of the Interior to the Public Health Service and has continued with the assumption of program operations by many tribes themselves. We trace developments in integration of community and public health practices in the provision of federal health care services for AI/AN persons and discuss recent trends.

Differences in risk factors for coronary heart disease among diabetic and nondiabetic individuals from a population with high rates of diabetes: the Strong Heart Study

CONTEXT

Coronary heart disease (CHD) is the leading cause of death in the United States.

OBJECTIVE

This study compares differences in risk factors for CHD in diabetic vs. nondiabetic Strong Heart Study participants.

DESIGN

This was an observational study.

SETTING

The study was conducted at three centers in Arizona, Oklahoma, and North and South Dakota.

PARTICIPANTS

Data were obtained from 3563 of 4549 American Indians free of cardiovascular disease at baseline.

INTERVENTION(S)

CHD events were ascertained during follow-up.

MAIN OUTCOME MEASURE

CHD events were classified using standardized criteria.

RESULTS

In diabetic and nondiabetic participants, 545 and 216 CHD events, respectively, were ascertained during follow-up (21,194 and 22,990 person-years); age- and sex-adjusted incidence rates of CHD were higher for the diabetic group (27.5 vs. 12.1 per 1,000 person-years). Risk factors for incident CHD common to both groups included older age, male sex, prehypertension or hypertension, and elevated low-density lipoprotein cholesterol. Risk factors specific to the diabetic group were lower high-density lipoprotein cholesterol, current smoking, macroalbuminuria, lower estimated glomerular filtration rate, use of diabetes medication, and longer duration of diabetes. Higher body mass index was a risk factor only for the nondiabetic group. The association of male sex and CHD was greater in those without diabetes than in those with diabetes.

CONCLUSIONS

In addition to higher incidence rates of CHD events in persons with diabetes compared with those without, the two groups differed in CHD risk factors. These differences must be recognized in estimating CHD risk and managing risk factors.

Obesity in adults is associated with reduced lung function in metabolic syndrome and diabetes: the Strong Heart Study

OBJECTIVE

The purposes of this study were to investigate whether reduced lung function is associated with metabolic syndrome (MS) and diabetes (DM) in American Indians (AIs) and to determine whether lower pulmonary function presents before the development of DM or MS.

RESEARCH DESIGN AND METHODS

The Strong Heart Study (SHS) is a multicenter, prospective study of cardiovascular disease (CVD) and its risk factors among AI adults. The present analysis used lung function assessment by standard spirometry at the SHS second examination (1993-1995) in 2,396 adults free of overt lung disease or CVD, with or without DM or MS. Among MS-free/DM-free participants, the development of MS/DM at the SHS third examination (1996-1999) was investigated.

RESULTS

Significantly lower pulmonary function was observed for AIs with MS or DM. Impaired pulmonary function was associated with MS and DM after adjustment for age, sex, abdominal obesity, current smoking status, physical activity index, hypertension, and SHS field center. Both forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were negatively associated with insulin resistance or DM severity and with serum markers of inflammation (P < 0.05). FVC and FEV1-to-FVC ratio both predicted DM in unadjusted analyses but not when adjusted for covariates, including waist circumference. In the adjusted model, abdominal obesity predicted both MS and DM.

CONCLUSIONS

Reduced lung function is independently associated with MS and with DM, and impaired lung function presents before the development of MS or DM; these associations may result from the effects of obesity and inflammation.

Advantages of video questionnaire in estimating asthma prevalence and risk factors for school children: findings from an asthma survey in American Indian youth

OBJECTIVES

The aims of the present study were to estimate the prevalence and risk factors of asthma among a sample of American Indian youth and to evaluate survey instruments used in determining asthma prevalence and risk factors.

METHODS

Three hundred and fifty-two adolescents aged 9 to 21 years enrolled in an Indian boarding school completed an asthma screening. The survey instruments were a written questionnaire and a video-illustrated questionnaire prepared from the International Study of Asthma and Allergies in Childhood (ISAAC), school health records, and a health questionnaire. Participants also underwent spirometry testing.

RESULTS

The prevalence of self-reported asthma varied from 12.7% to 13.4% depending upon the instrument used and the questions asked. A history of hay fever, respiratory infections, and family history of asthma were found to be risk factors for asthma by all instruments. Female gender and living on a reservation were significantly associated with asthma by some, but not all, instruments. Airway obstruction was highly associated with one asthma symptom (wheeze) shown in the video questionnaire. Associations for most risk factors with asthma were strongest for the video questionnaire.

CONCLUSIONS

The prevalence of self-reported asthma among these American Indian youth was similar to rates reported for other ethnic groups. The video-based questionnaire may be the most sensitive tool for identifying individuals at risk for asthma.

Asthma in American Indian adults: the Strong Heart Study

BACKGROUND

Despite growing recognition that asthma is an important cause of morbidity among American Indians, there has been no systematic study of this disease in older adults who are likely to be at high risk of complications related to asthma. Characterization of the impact of asthma among American Indian adults is necessary in order to design appropriate clinical and preventive measures.

METHODS

A sample of participants in the third examination of the Strong Heart Study, a multicenter, population-based, prospective study of cardiovascular disease in American Indians, completed a standardized respiratory questionnaire, performed spirometry, and underwent allergen skin testing. Participants were > or = 50 years old.

RESULTS

Of 3,197 participants in the third examination, 6.3% had physician-diagnosed asthma and 4.3% had probable asthma. Women had a higher prevalence of physician-diagnosed asthma than men (8.2% vs 3.2%). Of the 435 participants reported in the asthma substudy, morbidity related to asthma was high: among those with physician-diagnosed asthma: 97% reported trouble breathing and 52% had severe persistent disease. The mean FEV(1) in those with physician-diagnosed asthma was 61.3% of predicted, and 67.2% reported a history of emergency department visits and/or hospitalizations in the last year, yet only 3% were receiving regular inhaled corticosteroids.

CONCLUSIONS

The prevalence of asthma among older American Indians residing in three separate geographic areas of the United States was similar to rates in other ethnic groups. Asthma was associated with low lung function, significant morbidity and health-care utilization, yet medications for pulmonary disease were underutilized by this population.

Long-term efficacy of BCG vaccine in American Indians and Alaska Natives: A 60-year follow-up study

CONTEXT

The duration of protection from tuberculosis of BCG vaccines is not known.

OBJECTIVE

To determine the long-term duration of protection of a BCG vaccine that was previously found to be efficacious.

DESIGN

Retrospective record review using Indian Health Service records, tuberculosis registries, death certificates, and supplemental interviews with trial participants.

SETTING AND PARTICIPANTS

Follow-up for the period 1948-1998 among American Indians and Alaska Natives who participated in a placebo-controlled BCG vaccine trial during 1935-1938 and who were still at risk of developing tuberculosis. Data from 1483 participants in the BCG vaccine group and 1309 in the placebo group were analyzed.

MAIN OUTCOME MEASURES

Efficacy of BCG vaccine, calculated for each 10-year interval using a Cox regression model with time-dependent variables based on tuberculosis events occurring after December 31, 1947 (end of prospective case finding).

RESULTS

The overall incidence of tuberculosis was 66 and 138 cases per 100 000 person-years in the BCG vaccine and placebo groups, respectively, for an estimate of vaccine efficacy of 52% (95% confidence interval, 27%-69%). Adjustments for age at vaccination, tribe, subsequent BCG vaccination, chronic medical illness, isoniazid use, and bacille Calmette-Guérin strain did not substantially affect vaccine efficacy. There was slight but not statistically significant waning of the efficacy of BCG vaccination over time, greater among men than women.

CONCLUSION

In this trial, BCG vaccine efficacy persisted for 50 to 60 years, suggesting that a single dose of an effective BCG vaccine can have a long duration of protection.

The health status of American Indian and Alaska native males

OBJECTIVES

This study summarizes current health status information relating to American Indian and Alaska Native (AI/AN) males compared with that of AI/AN females.

METHODS

I analyzed published data from the Indian Health Service for 1994 through 1996 to determine sex differences in morbidity and mortality rates and use of health care facilities.

RESULTS

AI/AN males' death rates exceed those of AI/AN females for every age up to 75 years and for 6 of the 8 leading causes of death. Accidents, suicide, and homicide are epidemic among AI/AN males. Paradoxically, AI/AN males contribute only 37.9% of outpatient visits, versus 62.1% for females, and only 47% of hospitalizations excluding childbirth.

CONCLUSIONS

AI/AN males suffer inordinately from a combination of increased burden of illness and lack of utilization of health care services. Programs targeted to anomie, loss of traditional male roles, and violence and alcoholism are among the most urgently needed.

Spirometry reference values for American Indian adults: results from the Strong Heart Study

STUDY OBJECTIVE

To derive spirometry normative values from a large population of American Indian adults and compare them to reference values for white adults.

DESIGN

Pulmonary function was assessed using spirometry in participants of the Strong Heart Study, a multicenter, community-based, prospective study of cardiovascular risk factors and disease in American Indians, utilizing American Thoracic Society guidelines and a vigorous quality assurance program.

SETTING

Central Arizona, southwestern Oklahoma, central South Dakota, and northeastern North Dakota.

PARTICIPANTS

Acceptable spirometry results were obtained from 1,619 women and 1,005 men aged 45 to 74 years.

RESULTS

Internal reference values and normal ranges for FEV(1), FVC, and the FEV(1)/FVC ratio were derived from a healthy subgroup of 253 women and 190 men, identified by excluding participants with factors associated with a lower FEV(1). Ten percent of the entire cohort (269 of 2,624 subjects) had airways obstruction, as defined by an FEV(1)/FVC below the lower limit of the normal (LLN) using the internal reference equations. After allowing for measurement "noise," 31 participants were below the LLN using reference equations for white adults from the large National Health and Nutrition Examination Study (NHANES) III study but were normal using the internal reference equations (1.3% false-positive), while 27 participants were classified as normal using NHANES III equations but had airways obstruction using the internal reference equations (1.2% false-negative). Similarly low misclassification rates were seen for a low FVC (prevalence, 17.6%).

CONCLUSION

For clinical purposes, NHANES III spirometry reference equations for white adults may be used when testing American Indian women and men aged 45 to 74 years.

A population-based assessment of left ventricular systolic dysfunction in middle-aged and older adults: the Strong Heart Study

BACKGROUND

Although clinical congestive heart failure (CHF) is increasingly common, few data document the prevalence and correlates of underlying left ventricular (LV) systolic dysfunction (D) in population-based samples.

METHODS

Echocardiography was used in the second Strong Heart Study (SHS) examination to identify mild and severe LVD (LV ejection fraction [EF] 40%-54% and <40%, respectively) in 3184 American Indians.

RESULTS

Mild and severe LVD were more common in men than women (17.4% vs 7.2% and 4.7% vs 1.8%) and in diabetic than nondiabetic participants (12.7% vs 9.1% and 3.5% vs 1.6%). Stepwise increases were observed from participants with normal EF to those with mild and severe LVD in age (mean 60 vs 61 and 63 years, P <.001), prevalence of overt CHF (2% vs 6% and 28%) and definite coronary heart disease (3% vs 11% and 32%), systolic pressure (129 vs 135 and 136 mm Hg), serum creatinine level (0.98 vs 1.34 and 2.16 mg/dL), and log urinary albumin/creatinine level (3.2 vs 3.7 and 4.7); a negative relation was seen with body mass index (31.1 vs 31.0 and 28.4 kg/m(2)) (all P <.001). In multivariate analyses lower LVEFs were independently associated with clinical CHF and coronary heart disease, lower myocardial contractility, male sex, hypertension, overweight, arterial stiffening (higher pulse pressure/stroke volume) and renal dysfunction (higher serum creatinine level), higher LV mass, and lower relative wall thickness.

CONCLUSIONS

LVD, present in approximately 14% of middle-aged to elderly adults, is independently associated with overt heart failure and coronary heart disease, male sex, hypertension, overweight, arterial stiffening, and renal target organ damage and, less consistently, with older age and diabetes.

How to establish a lasting relationship with your host: lessons learned from Mycobacterium spp

Mycobacterium spp. enjoy an intracellular lifestyle that is fatal to most microorganisms. Bacilli persist and multiply within mononuclear phagocytes in the face of defences ranging from toxic oxygen and nitrogen radicals, acidic proteases and bactericidal peptides. Uptake of Mycobacterium by phagocytes results in the de novo formation of a phagosome, which is manipulated by the pathogen to accommodate its needs for intracellular survival and replication. The present review describes the intracellular compartment occupied by Mycobacterium spp. and presents current ideas on how mycobacteria may establish this niche, placing special emphasis on the involvement of mycobacterial cell wall lipids.

Differences in echocardiographic findings and systemic hemodynamics among non-diabetic American Indians in different regions: The Strong Heart Study

PURPOSE

This study was undertaken to determine whether differences in left ventricular (LV) and systemic hemodynamic findings exist between American Indians in different regions that might contribute to known differences in cardiovascular morbidity rates among American Indians.

METHODS

We compared echocardiography results in 290 non-diabetic Strong Heart Study (SHS) participants in Arizona, 595 in Oklahoma and 572 in North/South Dakota (ND/SD).

RESULTS

Participants in the 3 regions were similar in age and gender but those in Arizona had the highest body mass indices and lowest heart rates while those in ND/SD had the lowest diastolic blood pressures (BP). In analyses that adjusted for significant covariates, ND/SD participants had larger aortic (Ao) anular, Ao root, and LV chamber size as well as higher cardiac output and lower peripheral resistance, whereas Arizona participants had increased LV wall thickness and mass and reduced LV myocardial contractility. These findings may contribute to the known high rates of cardiovascular events in ND/SD Indians and to the proportionately higher rate of cardiovascular death than of non-fatal cardiovascular events that has been recently documented in Arizona Indians.

CONCLUSIONS

Application of echocardiography to non-diabetic SHS participants reveals that LV chamber and arterial size are larger in ND/SD Indians and that LV wall thicknesses and mass are higher and LV myocardial contractility lower in Arizona Indians, possibly contributing to the higher than expected rates of cardiovascular morbidity and mortality among Indians in Arizona.

Impact of diabetes on cardiac structure and function: the strong heart study

BACKGROUND

Whether diabetes mellitus (DM) adversely affects left ventricular (LV) structure and function independently of increases in body mass index (BMI) and blood pressure is controversial.

METHODS AND RESULTS

Echocardiography was used in the Strong Heart Study, a study of cardiovascular disease in American Indians, to compare LV measurements between 1810 participants with DM and 944 with normal glucose tolerance. Participants with DM were older (mean age, 60 versus 59 years), had higher BMI (32.4 versus 28.9 kg/m(2)) and systolic blood pressure (133 versus 124 mm Hg), and were more likely to be female, to be on antihypertensive treatment, and to live in Arizona (all P<0.001). In analyses adjusted for covariates, women and men with DM had higher LV mass and wall thicknesses and lower LV fractional shortening, midwall shortening, and stress-corrected midwall shortening (all P<0.002). Pulse pressure/stroke volume, a measure of arterial stiffness, was higher in participants with DM (P<0.001 independent of confounders).

CONCLUSIONS

Non-insulin-dependent DM has independent adverse cardiac effects, including increased LV mass and wall thicknesses, reduced LV systolic chamber and myocardial function, and increased arterial stiffness. These findings identify adverse cardiovascular effects of DM, independent of associated increases in BMI and arterial pressure, that may contribute to cardiovascular events in diabetic individuals.

Effective preexposure tuberculosis vaccines fail to protect when they are given in an immunotherapeutic mode

Two vaccine formulations previously shown to induce protective immunity in mice and prevention of long-term necrosis in guinea pigs were tested as potential immunotherapeutic vaccines in mice earlier infected by aerosol with Mycobacterium tuberculosis. Neither vaccine had any effect on the course of the infection in the lungs, but both reduced the bacterial load in the spleen. Similarly, inoculation with Mycobacterium bovis BCG had no effect whatsoever and, if given more than once, appeared to induce an increasingly severe pyogranulomatous response in the lungs of these mice.

Trafficking and release of mycobacterial lipids from infected macrophages

Analysis of infected macrophages revealed that lipid-containing moieties of the mycobacterial cell wall are actively trafficked out of the mycobacterial vacuole. To facilitate the analysis of vesicular trafficking from mycobacteria-containing phagosomes, surface-exposed carbohydrates were labeled with hydrazide-tagged markers. The distribution of labeled carbohydrate/lipid moieties and subsequent interaction with cellular compartments were analyzed by immunoelectron microscopy and by fluorescence microscopy of live cells. The released mycobacterial constituents were associated with several intracellular organelles and were enriched strikingly in tubular endocytic compartments. Subcellular fractionation of infected macrophages by density gradient electrophoresis showed temporal movement of labeled bacterial constituents through early and late endosomes. Thin layer chromatography analysis of these subcellular fractions confirmed their lipid nature and revealed five dominant bacteria-derived species. These mycobacterial lipids were also found in extracellular vesicles isolated from the medium and could be observed in un-infected 'bystander' cells. Their transfer to bystander cells could expand the bacteria's sphere of influence beyond the immediate confines of the host cell.

Rising tide of cardiovascular disease in American Indians. The Strong Heart Study

BACKGROUND

Although cardiovascular disease (CVD) used to be rare among American Indians, Indian Health Service data suggest that CVD mortality rates vary greatly among American Indian communities and appear to be increasing. The Strong Heart Study was initiated to investigate CVD and its risk factors in American Indians in 13 communities in Arizona, Oklahoma, and South/North Dakota.

METHODS AND RESULTS

A total of 4549 participants (1846 men and 2703 women 45 to 74 years old) who were seen at the baseline (1989 to 1991) examination were subjected to surveillance (average 4.2 years, 1991 to 1995), and 88% of those remaining alive underwent a second examination (1993 to 1995). The medical records of all participants were exhaustively reviewed to ascertain nonfatal cardiovascular events that occurred since the baseline examination or to definitively determine cause of death. CVD morbidity and mortality rates were higher in men than in women and were similar in the 3 geographic areas. Coronary heart disease (CHD) incidence rates among American Indian men and women were almost 2-fold higher than those in the Atherosclerosis Risk in Communities Study. Significant independent predictors of CVD in women were diabetes, age, obesity (inverse), LDL cholesterol, albuminuria, triglycerides, and hypertension. In men, diabetes, age, LDL cholesterol, albuminuria, and hypertension were independent predictors of CVD.

CONCLUSIONS

At present, CHD rates in American Indians exceed rates in other US populations and may more often be fatal. Unlike other ethnic groups, American Indians appear to have an increasing incidence of CHD, possibly related to the high prevalence of diabetes. In the general US population, the rising prevalence of obesity and diabetes may reverse the decline in CVD death rates. Therefore, aggressive programs to control diabetes and its risk factors are needed.

Similar responses by macrophages from young and old mice infected with Mycobacterium tuberculosis

The growth of four isolates of Mycobacterium tuberculosis was compared in cultures of bone marrow-derived macrophages generated from young (3 months) and old (24 months) female C57BL/6 mice. In all four cases, no differences were seen in the course of the in vitro infection over a 10-day culture period. Macrophages from both young and old mice secreted similar levels of nitric oxide if treated with interferon gamma (IFN) 24 h prior to infection. Expression of mRNA encoding an array of early response genes in the two sets of cultures was also generally similar. These data indicate that the capacity of macrophages to respond to infection with a virulent intracellular bacterial infection does not seem to be influenced by the increasing age of the host.

Progression of chronic pulmonary tuberculosis in mice aerogenically infected with virulent Mycobacterium tuberculosis

There are several critical differences in the pulmonary granulomatous response to Mycobacterium tuberculosis between the mouse and other animal models such as the guinea pig or rabbit. One key difference is a conspicuous lack of central caseating necrosis in pulmonary lesions of immunologically intact mice. To determine whether normal mice could develop such pathology in response to highly virulent clinical isolates of M. tuberculosis, C57BL/6 mice were infected aerogenically with varying doses of three different strains, and the development of a granulomatous response was followed for as long as a year. Whereas such conditions failed to induce caseating necrosis in the lungs of these mice, all of the infections induced a granulomatous response which progressed similarly. We present here a descriptive report of the gross pathological progression of tuberculosis in the lungs of the mice. In each case, the disease progressed in five discrete stages, which were delineated on the basis of several criteria including the extent of granulomatous involvement, the cell types present, the degree of lymphocyte organization, and the presence of destructive sequelae such as airway epithelium erosion and airway debris. Quicker progression of disease along these five stages was induced by increasing the size of the inoculum or by the more virulent mycobacterial strains. The infections with the virulent strains were not resolved, and the later stages of the granulomatous response coincided with an increasing bacillary load and a loss of organized lymphocytes in the infected lungs which ultimately resulted in the death of the host. These results indicate that although C57BL/6 mice do not manifest a caseating form of pulmonary tuberculosis, they manifest an equally pathogenic granulomatous response which appears as a chronic interstitial fibrosing response that fails to contain the infection at a time that organized lymphocyte involvement wanes in the lung.

All-cause mortality and cardiovascular disease mortality in three American Indian populations, aged 45-74 years, 1984-1988. The Strong Heart Study

Community mortality surveillance for 1984-1988 was conducted by researchers of the Strong Heart Study, which examined the incidence, prevalence, and risk factors of cardiovascular disease in three American Indian populations, aged 45-74 years, in Arizona, Oklahoma, and South/North Dakota. All-cause and cardiovascular disease mortality rates were determined through the use of death certificate data. Cardiovascular disease deaths were confirmed by independent systematic review of medical records. In all three populations, men had higher all-cause and cardiovascular disease mortality rates than did women. Oklahoma exhibited slightly lower 5-year, age-adjusted, all-cause mortality (96/1,000) than did Arizona (107/1,000) and South/North Dakota (114/1,000). The leading cause of death among both sexes in Oklahoma and in South/North Dakota was cardiovascular disease. Diabetes mellitus led among Arizona women. The other major causes of death were cancer, liver disease including cirrhosis, and injury. When compared with the rates in each state, average annual all-cause mortality rates were higher for the American Indian populations in almost every age group. The all-cause annual mortality rates in the three Indian populations were close to rates in the US black population and higher than the rates of the entire US population and of US whites. This trend was amplified in the 45- to 64-year age group. Only in the 65- to 74-year age group did mortality rates in the Indian population approach those of the US population. Cardiovascular disease mortality rates were close to the US averages in Arizona and Oklahoma, but they were more than two times higher in South/North Dakota among those between 45 and 64 years of age. Thus, American Indians in Arizona, Oklahoma, and South/North Dakota exhibit high all-cause mortality rates. In particular, the South/North Dakota population cardiovascular disease death rate appears to present a potential target for community-based programs to intervene on known risk factors to promote healthy lifestyles.

Disruption of the cellular inflammatory response to Listeria monocytogenes infection in mice with disruptions in targeted genes

The results of this study to dissect the nature of the acquired immune response to infection with Listeria monocytogenes in mice with targetted gene disruptions show that successful resolution of disease requires the essential presence of alphabeta T cells and the capacity to elaborate gamma interferon. In the absence of either of these entities, mice experience increasingly severe hepatitis and tissue necrosis and die within a few days. The data from this study support the hypothesis that the protective process is the efficient replacement of neutrophils in lesions by longer-lived mononuclear phagocytes; alphabeta-T-cell-knockout mice died from progressive infection before neutrophil replacement could occur, whereas in gammadelta-T-cell-knockout mice this replacement process in the liver has previously been shown to be much slower. In the present study we attribute this delay to reduced production of the macrophage-attracting chemokine MCP-1 in the gammadelta-T-cell-knockout animals. These data further support the hypothesis that gammadelta T cells are important in controlling the inflammatory process rather than being essential to the expression of protection.

The changing requirements for health manpower and the University of Oklahoma College of Medicine

Sweeping national changes in health care financing and delivery are forcing major modifications in the numbers, types, and distribution of physician manpower thought to be appropriate for the new paradigms. Not surprisingly, these changes are exerting great pressure on medical education institutions to also adapt to the changing requirements. In Oklahoma, these financial and policy changes are accompanied by demands upon the colleges of medicine to increase the numbers of physicians who locate their practices in rural locations. The maintenance of a comprehensive and well balanced basic and advanced medical education effort within these complex and shifting requirements continues to tax the abilities of all faculties, including the Oklahoma University College of Medicine (OUCOM).

Susceptibility of a panel of virulent strains of Mycobacterium tuberculosis to reactive nitrogen intermediates

Murine bone marrow-derived macrophages were infected with a panel of virulent isolates of Mycobacterium tuberculosis including laboratory strains Erdman and H37Rv and various clinical isolates in order to determine the sensitivity of each of these strains to the antimycobacterial activities of macrophage-generated reactive nitrogen intermediates (RNI). All of the M. tuberculosis strains grew in murine bone marrow-derived macrophages; however, gamma interferon-primed macrophages limited the initial growth of intracellular bacilli. Some of the mycobacterial strains, including Erdman, were killed over the first 4 days of infection, as evidenced by significant decreases in the number of viable intracellular bacilli determined by a CFU assay. Other mycobacterial strains were not killed during this same period, and some isolates, including CSU 24 and CSU 31, grew steadily in activated macrophages. The accumulation of nitrite on infected monolayers was measured, and it was found that inhibitory levels of RNI did not vary among infections with the different strains. Nitrite tolerance was determined in a cell-free system for each of the strains in order to compare susceptibilities of the strains to RNI. All of the strains tested were killed by levels of RNI generated by the acidification of 10 mM NaNO2 to pH 6.5 or 5.5, and the strains exhibited a range of tolerance to lower concentrations of RNI. No correlations were observed between such cell-free RNI tolerances and the capacity of bacilli to resist macrophage RNI-mediated killing. These results indicate that under stringent conditions, RNI can kill M. tuberculosis, but that under less harsh, more physiological conditions, the effects of RNI range from partial to negligible inhibition.

Health care of Oklahoma Indians

The many unique aspects of Indian life extend into the health care arena, of special interest in Oklahoma, the "home of the red man." The long historical relationship of certain Indian tribes with the federal government has resulted in one of the most complicated social, administrative, and governmental arrangements anywhere. A consequence of this relationship was, in effect, a business transaction resulting in the ceding of virtually all Indian lands of the U.S. and an assumption by the latter to provide certain services, including health care, to affected tribes. With the 33 different tribes in Oklahoma; the dual entitlement possessed by Indian people; the contributions of the Indian Health Service to the economy of Oklahoma; and the growing revolution in health care, knowledge of the special circumstances of Indian life and health care is important even for practitioners who do not regularly encounter Indian people in their own practices.

Rheumatoid arthritis in a United States Public Health Service Hospital in Oklahoma: serologic manifestations in rheumatoid arthritis vary among tribal groups

OBJECTIVE

To study the serologic manifestations of rheumatoid arthritis (RA) at a United States Public Health Service Hospital that serves numerous tribes in Oklahoma.

METHODS

Forty-five patients with RA were identified, and serologic studies for antinuclear antibody (ANA), rheumatoid factor, and antibodies to extractable nuclear antigens were performed. Extraarticular manifestations of RA were also evaluated.

RESULTS

Twelve of the 45 patients with RA were Kiowa. These patients were significantly more likely to have a positive ANA (75%) than the other patients with RA (28%). In addition, anti-Ro was significantly more common among Kiowa (33%) than among members of other tribes (3%). There was no difference in the extraarticular manifestations of the Kiowa compared with the other Native American tribes.

CONCLUSION

RA can be distinctly characterized by serology among groups of American Indians living in the same geographic area.

American Indians and Alaska Natives--overview of the population

THE ESTIMATED TWO MILLION American Indians and Alaska Natives, while sharing certain genetic traits, belong to groups with distinct social, cultural, political, and biomedical attributes. They share with certain other ethnic minorities high poverty rates, low educational attainment, increased susceptibility to certain diseases, and elevated mortality rates. Hypertension has been reported less frequently among American Indians compared to other U.S. groups, but is increasing in frequency, is strongly associated with obesity and diabetes, and is synergistically associated with diabetes in the etiology of end-stage renal disease. The first priority for dealing with hypertension among American Indians is to maximize efforts toward control. The Indian Health Service (IHS) provides such an opportunity, which is not as readily available to other minorities. In addition to controlling hypertension, areas of fruitful investigation include studies relating hypertension to acculturation, physiology of peripheral adrenergic vasoreceptors, salt and water metabolism, and prevention or amelioration of end-stage renal disease. Understanding some of these basic processes will prove valuable for American Indians and Alaska Natives as well as the entire population.

The University of Oklahoma College of Medicine Rural Health Educational Program

Training of physicians to meet the health care needs of rural residents has long been a priority of the University of Oklahoma College of Medicine. With establishment of the much imitated Rural Preceptorship Program in 1948, the college launched an ongoing series of efforts all directed toward increasing the number of graduates choosing to practice in rural locations. In addition to the required senior Preceptorship Program, a series of educational programs is available in each year of medical school, actually beginning prior to freshman enrollment. As a result, the college now offers a comprehensive series of educational experiences involving not only four years of medical school, but graduate training in the primary care specialties as well. This report summarizes the various activities of the college that now make up the rural emphasis program, all of which are designed to help ensure an adequate supply of physicians for rural Oklahoma.

Chemokine response in mice infected with Mycobacterium tuberculosis

We show here that infection of murine macrophages with various strains of Mycobacterium tuberculosis induces the rapid in vitro expression of genes encoding chemokines macrophage inflammatory protein 1 alpha and macrophage inflammatory protein 2, which recruit neutrophils to sites of infection, and macrophage-recruiting chemokines 10-kDa, interferon-inducible protein (IP-10) and macrophage chemotactic protein 1. Three strains of M. tuberculosis, Erdman and the clinical isolates CSU 22 and CSU 46, induced similar levels of secretion of macrophage chemotactic protein 1 from infected macrophage monolayers; however, the Erdman strain failed to induce levels of secretion of tumor necrosis factor alpha similar to those induced by either CSU 22 or CSU 46. Using a low-dose aerosol infection model, we also found that while the Erdman strain induced negligible increases in chemokine mRNA levels in the lungs, infection with either CSU 22 or CSU 46 resulted in greater levels of mRNA production for all four chemokines tested. The growth of these strains in the lungs was, however, equally well contained by acquired host immunity. These data allow us to hypothesize that the chemokine response in the lungs probably does not control the protective granulomatous response and that perhaps other T-cell- or macrophage-associated cytokines such as tumor necrosis factor alpha or interleukin 12 may be involved in this process.

The role of interleukin-12 in acquired immunity to Mycobacterium tuberculosis infection

The early phase of acquired cellular immunity to Mycobacterium tuberculosis infection is mediated by the emergence of protective CD4 T lymphocytes that secrete cytokines including interferon-gamma (IFN-gamma), a molecule which is pivotal in the expression of resistance to tuberculosis. Recent evidence demonstrates that infection with M. tuberculosis induces peripheral blood mononuclear cells to release the cytokine interleukin-12 (IL-12), a molecule that promotes the emergence of T-helper type-1 (Th1), IFN-gamma-producing T cells. We demonstrate here that IL-12 mRNA expression was induced by M. tuberculosis infection both in vivo and in vitro and that exogenous administration of IL-12 to mice transiently resulted in increased resistance to the infection. IL-12 also increased the production of IFN-gamma by both splenocytes derived from infected animals treated in vivo and by antigen-stimulated CD4 cells from untreated infected animals, with maximal effects at times associated with the expansion of antigen-specific CD4 T cells in vivo. In the absence of a T-cell response, as seen in SCID mice or nude mice, IL-12 only slightly augmented the moderate bacteriostatic capacity of these immunocompromised mice. Neutralization of IL-12 by specific monoclonal antibodies resulted in a reduction in granuloma integrity and slowing of the capacity of the animal to control bacterial growth.

Mortality of American Indian and Alaska native infants

Accurate determination of infant mortality rates among Indians in seriously hampered by variations in the identification of Indian persons and use of different subsets of the Indian population for various purposes. Lack of consistency in the reporting of racial origin on birth and death records is a source of substantial error. Because of these factors, more than the usual care must attend comparisons and inferences drawn from data in which these differences are present. At present, it would seem prudent to regard all data about American Indians as provisional. Even though Indian infant mortality remains higher than that for US all races, regardless of techniques used for estimates, the decline of Indian infant mortality by more than 80% since the establishment of the IHS is a truly remarkable achievement. This success has been ascribed to a combination of activities, including the provision of safe drinking water, especially as an integral part of the IHS program; the nearly universal immunization of Indian children; and emphasis upon comprehensive, community-oriented programs focused on maternal and child care. These successes have contributed to changes in the distribution of the leading causes of Indian infant mortality, so that the most prominent causes now are SIDS, congenital anomalies, injuries, and various infections. Because of these changes and advances in knowledge, the IHS has recently revised its five-year plan for dealing with infant mortality to provide greater attention to injuries and infections and has embarked upon a series of discussions with the American Academy of Pediatrics to address postneonatal deaths and the difficult problem of SIDS. Low socioeconomic conditions, so important in influencing mortality rates (7, 14, 29), have thus far proved to be intractable. In the meantime, success will depend upon ensuring optimal prenatal care, reducing those risk factors amenable to correction, and solving the problem of SIDS.

The University of Oklahoma College of Public Health and the American Indian

This article illustrates how the relationship between the University of Oklahoma College of Public Health, the American Indians, and the Indian Health Service is especially appropriate to the state of Oklahoma. It reviews the development of the College of Public Health as an important component of the university and the state of Oklahoma. Included are observations about the special contributions made by American Indians to both the nation and to the state, as well as reflections upon the development of public health in the young nation and in the newly forming state of Oklahoma.

The major respiratory diseases of American Indians

The most prominent respiratory diseases of American Indian adults are pneumonia, cancer of the lung, chronic obstructive pulmonary disease (COPD), and tuberculosis. Mortality and hospitalization rates of these diseases were compared with those for the rest of the U.S. population and between Indian groups in the various Indian Health Service Areas. Pneumonia and influenza constitute the sixth leading cause of death among Indians and the fifth leading cause of death among the U.S. All Races population. Chronic obstructive pulmonary disease is the fourth leading cause of death among U.S. All Races, but only the tenth leading cause of death among Indians. Pneumonia and tuberculosis are more significant causes of death and disability for Indians than are COPD and cancer of the lung. The explanation for these differences in mortality rates between Indians and the general population are not known. Respiratory system diseases are responsible for 10.6% of Indian hospitalizations. The most frequent is pneumonia, which accounts for approximately 4% of all Indian hospitalizations. Differences in respiratory diseases between Indian groups are sometimes striking, with a sharp increase in mortality and hospitalization in the Areas across the northern border of the lower 48 states. There is also a much higher prevalence of cigarette smoking in those same Areas.

The Indian Health Service approach to alcoholism among American Indians and Alaska Natives

The transfer to the Indian Health Service (IHS) of 158 alcohol treatment programs that had been administered by the National Institute on Alcohol Abuse and Alcoholism began in 1978. Today, approximately 300 alcohol and substance abuse treatment programs offer services to American Indians, among them primary residential treatment, halfway houses, outreach, and aftercare. This system provides a national network upon which additional activities may be established. Along with increasing its attention to health promotion and disease prevention, the IHS has moved toward the prevention of alcoholism. A variety of preventive programs are in place that emphasize improved self-image, value and attitude clarification, decision-making, and physical and emotional effects of alcohol and substance abuse. Many begin as Head Start programs and continue through adulthood. In 1986, after consulting with both academic and tribal experts, the IHS devised a strategic plan for alcoholism control that stresses comprehensive care and prevention activities; it serves as a guide for further program development. The Secretary of Health and Human Services created a Task Force on Indian Alcoholism in 1986 to serve as a coordinating body for activities carried out by the IHS and other agencies and units of the Department. Passage of the Anti-Drug Abuse Act in 1986 added resources for the development of adolescent treatment centers and, more importantly, for community-based pre- and post-residential care for youths and their families. Concomitant with these initiatives have been several instances of increased attention by various tribes to the problem of alcoholism. The IHS strategic plan, together with the Secretary's initiative, the Anti-Drug Act, and tribal actions, has added substantial momentum to efforts directed at controlling alcoholism among American Indians. Although the mortality rate from alcoholism is about four times greater for the American Indian population than for the entire U.S. population, it decreased from 54.5 per 100,000 population to 26.1 between 1978 and 1985-a reduction of 52 percent.The philosophy of the IHS in emphasizing prevention of disease and promotion of wellness provides an opportunity for continuing the considerable progress already made. The critical and decisive role played by the Indian communities themselves will determine whether ultimate success can be achieved.

A comprehensive programme to reduce the incidence of hepatitis B virus infection and its sequelae in Alaskan natives

In 1983, a comprehensive programme was introduced to halt the spread of hepatitis B virus (HBV) infection and to reduce mortality from hepatocellular carcinoma (HCC) in Alaskan Natives, in whom the incidence of HBV infection was high. This programme includes: serological screening of all Alaskan Natives; immunisation of susceptible persons, including all newborn babies, with hepatitis B vaccine; and testing HBsAg-positive carriers twice a year for alpha-fetoprotein (AFP) to detect HCC at an early stage. By October, 1986, over 53,000 Alaskan Natives (84% of the total Native population) had been tested for HBV serological markers and 80% of the identified susceptibles had been or were being vaccinated against HBV. After complete immunisation of 90% of the susceptibles in the area with the highest infection rates in Alaska, the annual incidence of acute symptomatic HBV infection decreased from 215 to 14 cases per 100,000 population. After the introduction of AFP screening, the 1-year-case-fatality rate for HCC fell, from 100%, to 50%.

The Indian burden of illness and future health interventions

This article describes the burden of illness of Indians eligible for services from the Indian Health Service (IHS) and discusses strategies for reducing morbidity and mortality related to those conditions. To improve health to an extent that parallels the IHS's past achievements, the illnesses that now are prevelant among Indians require changes in personal and community behavior rather than intensified medical services. Analysis of these conditions leads to the conclusion that much of the existing burden of illness can be reduced or eliminated. IHS is responding to this challenge by continuing to ensure Indians' access to comprehensive health care services, by increasing educational efforts aimed at prevention, and by enlisting the support of other government and private organizations in activities that have as their purpose treating diseases if intervention will lessen morbidity and mortality (such as diabetes and hypertension) and encouraging of dietary changes, cessation of smoking, exercise, reduction in alcohol consumption, and other healthy behavior.

The organization of health services for Indian people

The Indian Health Service (IHS) is a bureau of the Health Resources and Services Administration, an agency of the Public Health Service. It was formed in 1955 by a transfer of health services from the Bureau of Indian Affairs, Department of the Interior. Since that time, IHS has grown larger and more complicated and has become a truly complex national organization that is responsible for direct and contract health care services to approximately 1 million Indian people. The historical background of the Service, its present organization, and the services that it provides through a variety of organizational structures are outlined in this report.

The Indian Health Service record of achievement

The Indian Health Service (IHS) was transferred from the Department of Interior to the Public Health Service in the Department of Health, Education, and Welfare in 1955. At that time, the general health of Indian people substantially lagged behind the rest of the U.S. population. This gap was reflected in mortality rates which were several-fold higher for Indians, or reflected in time; there were decades between the dates when the U.S. population achieved certain lower death rates compared with the dates when similar reductions were achieved by Indians. As a result of preventive health programs, improvements in sanitation, and the development of a number of medical advances, substantial progress has been achieved in improving the health of American Indians and Alaska Natives. Life expectancy of Indians has increased 20 years between 1940 and 1980. From 1955 through 1982, the death rate for Indian infants dropped by 82 percent. Also, the age-adjusted death rate for tuberculosis decreased from 57.9 per 100,000 population in 1955 to 3.3 in 1983. These and other improvements are summarized in this paper.