Differences in detection of alcohol use in a prenatal population (on a Northern Plains Indian Reservation) using various methods of ascertainment

Although Fetal Alcohol Syndrome (FAS) rates have been reported to be higher in American Indian populations, no screening tool has been validated for alcohol use in American Indian women. The objectives of this study were to compare the detection of prenatal alcohol use by a self-administered questionnaire to detection by clinical interview; and to ascertain whether the screening tool would increase detection of pregnant women who are abusing alcohol. The hospital records of the women were reviewed for any history of alcohol-related illnesses or injuries to compare with results obtained from the questionnaire. Seventy women attending their first prenatal clinic visit on a reservation were screened for alcohol use. There was a wide range in detection of prenatal alcohol use (20%-71% of the sample detected) depending on the method used. There was a large variation in sensitivities (7%-93%) of the individual questions in identifying patients detected as "high risk" by the clinicians. The T-ACE screening questions significantly increased detection of alcohol use compared to detection by the clinicians (p = 0.04 Fisher's exact test). Due to the large variation between different methods of detection, it is recommended that screening tools that increase detection of alcohol use should be combined with methods of higher specificity such as using questions about quantity and frequency of alcohol intake, medical chart review and clinical interview. We also found that various interpretations of the screening questions by the patients highlighted the need to tailor the wording of individual questions to the particular patient population.

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.

Physical activity and lipids and lipoproteins in American Indians ages 45-74

PURPOSE

The Strong Heart Study is a study of cardiovascular disease and its risk factors among American Indian men and women aged 45-74 yr representative of 13 communities from Arizona (AZ), Oklahoma (OK), and North/South Dakota (N/SD). This investigation sought to characterize the amount and type of physical activity and to determine the association between activity and lipids in this population.

METHODS

Total physical activity (occupational plus leisure) was assessed with a validated questionnaire.

RESULTS

Men and women from OK (21 +/- 19 and 16 +/- 15 h.wk-1; respectively) and N/SD (23 +/- 21 and 17 +/- 17 h.wk-1; respectively) had activity levels that were similar if not lower than the U.S. population with the AZ communities (17 +/- 21 and 10 +/- 14 h.wk-1; respectively) being substantially lower than the other two communities. Total cholesterol (TC), high density lipoprotein cholesterol (HDL-c), and low density lipoprotein cholesterol (LDL-c) levels were lower than the U.S. population.

CONCLUSIONS

For most of the population (diabetic men and nondiabetic men and women), activity was significantly associated (P < 0.05) with apolipoprotein (apo) AI after controlling for covariates. With levels of activity as low if not lower than the general U.S. population coupled with high prevalence of obesity and diabetes, efforts to increase physical activity in American Indians are warranted. Hopefully these increases in activity will result in favorable lipid changes as well as decreasing the risk of diabetes which is epidemic in these populations.

Relationship of prenatal alcohol use with maternal and prenatal factors in American Indian women

Demographic factors and patterns of substance use among women who did not consume alcohol during pregnancy were compared to women who did consume alcohol during pregnancy. One-hundred seventy-seven Northern Plains Indian women who received prenatal care at an urban clinic in a rural state were screened for substance use as part of the validation study with a self-administered questionnaire. Women who drank during pregnancy were more likely to be single and have less education than women who did not drink. While most of the women in the study had available transportation resources, the women who drank during pregnancy were less likely to have transportation than the women who did not drink. Women who drank during pregnancy consumed more alcohol more frequently before pregnancy than did women who drank before but not during pregnancy. Compared to women who did not drink during pregnancy, women who drank during pregnancy were more likely to smoke cigarettes and use illicit drugs, to have parents who drank, to feel they drank the same or more than other pregnant women, or to have experienced more relationship breakups and physical and emotional abuse. Prenatal patients who drink alcohol during pregnancy need more intensive counseling regarding their multiple risk behaviors.

Relation of LDL size to the insulin resistance syndrome and coronary heart disease in American Indians. The Strong Heart Study

Small, dense LDL has been shown to be associated with the insulin resistance syndrome and coronary heart disease (CHD). We examined the distribution of LDL size and phenotype within a population-based sample of American Indians to determine the relationships with prevalent CHD and to examine associations with hyperinsulinemia and other components of the insulin resistance syndrome. Data were available for 4505 men and women between 45 and 74 years of age who are members of 13 American Indian communities in three geographic areas. Diabetes, CHD, and CHD risk factors were assessed by standardized techniques, and LDL size was measured by gradient gel electrophoresis. LDL size was smaller in men than in women and in individuals with diabetes than in those without diabetes. In multivariate analysis, LDL size was significantly related to several components of the insulin resistance syndrome, including triglycerides (inversely) and HDL cholesterol (positively). Although univariate relations were positive, LDL size was not significantly related to fasting insulin concentrations or body mass index in the multivariate model. LDL size also showed no relationship to apolipoprotein E phenotype. When LDL size was compared in individuals with and without CHD, no significant differences were observed, either in nondiabetic or diabetic individuals. We conclude that LDL size is most strongly related to lipoprotein components of the insulin resistance syndrome, especially plasma triglycerides. However, in this population with low LDL, it is not related to cardiovascular disease.

Parity, postmenopausal estrogen use, and cardiovascular disease risk factors in American Indian women: the Strong Heart Study

Studies have suggested that high parity is related to an increased risk of cardiovascular disease (CVD). Reasons for an increased risk are unclear but may include influences of child-bearing on levels of CVD risk factors. The present study examined the associations of parity and CVD risk factors in American Indian women, among whom large families are common. Estrogen use and CVD risk factors also were assessed. The study included 1982 ever-married, postmenopausal women aged 45 through 74 years who participated in the Strong Heart Study (SHS), a large study of American Indians in three geographic areas of the United States. Information was obtained during a physical examination and interview. Parity ranged from 0 to 18 (median 5). Current estrogen use varied from 5% in Arizona to 21% in Oklahoma. Multivariable analyses found a statistically significant, inverse association between parity and high-density lipoprotein (HDL) cholesterol, although the difference with increasing parity was small (-0.26 mg/dl per additional live birth). Estrogen users had significantly lower levels of low-density lipoprotein cholesterol (-6.4 mg/dl) and fibrinogen (-26.2 mg/dl) and a lower waist/hip ratio (-0.02), and higher values of HDL (5 mg/dl) and logarithm (ln) triglyceride (0.13 mg/dl). Current users were slightly more likely to be hypertensive (prevalence odds ratio, 1.56). Relations between parity and CVD risk factors in American Indian women with high parity suggested only small differences with increasing parity. Associations with estrogen use are much stronger and are similar to those observed in other groups of women.

Intake of nutrients related to cardiovascular disease risk among three groups of American Indians: the Strong Heart Dietary Study

BACKGROUND

Although diet is implicated in the elevated rate of cardiovascular disease among some American Indian tribes, the dietary intakes of these individuals have not been described. The Strong Heart Dietary Study compared diets of 10 tribes in Arizona, Oklahoma, and the Dakotas to examine the possible contribution of diet to cardiovascular and other chronic diseases.

METHODS

During 1988-1991, 892 people responded to a 24 hr diet recall questionnaire. Nutrient intake by study area, sex, and age group were compared by analysis of variance, and intakes were compared with nutrient intakes reported by participants in Phase 1 of the Third National Health and Nutrition Examination Survey and with dietary recommendations of the National Research Council, the American Heart Association, and the Healthy People 2000 objectives.

RESULTS

The intake of energy and nutrients varied significantly by sex and age. Men consumed more energy, macronutrients, and sodium than did women (P < or = 0.001). Women's diets were denser in carbohydrate, beta-carotene, vitamin C, and vitamin E than were men's diets (P < or = 0.001). Younger participants consumed more energy, macronutrients, vitamin E, and sodium than did older participants (P < or = 0.001). Older participants had diets denser in protein and beta-carotene than did younger participants (P < or = 0.001). Energy intake did not differ significantly by study area, but men in Arizona consumed more energy from carbohydrate and less energy from total fat than did men elsewhere (P < or = 0.01). Men and women in Arizona consumed more cholesterol and fiber than did other participants (P < or = 0.01) and less of the antioxidant vitamins (P < or = 0.01). Participants in the Strong Heart Diet Study reported diets higher in fats and cholesterol than did participants in Phase 1 of the Third National Health and Nutrition Examination Survey. Few Strong Heart participants achieved dietary recommendations for the reduction of risk of chronic disease.

CONCLUSIONS

Area differences in nutrient intake were observed, but most participants consumed diets associated with increased risk of heart disease and other chronic diseases. Women and older participants in general reported healthier nutrient intakes. Dietary intervention programs should educate American Indians about dietary modifications to reduce the risk of cardiovascular and other nutrition-related disorders.

Relations of Doppler stroke volume and its components to left ventricular stroke volume in normotensive and hypertensive American Indians: the Strong Heart Study

Doppler echocardiographic measurement of time-velocity integral of blood flow across the aortic annulus ("stroke distance") or of stroke volume (SV) have been proposed as noninvasive measures of cardiac pump performance that could elucidate the hemodynamics of hypertension. To evaluate the performance of these measures of hemodynamic volume load in a population with a wide range of body build and other characteristics, we obtained technically adequate imaging and Doppler echocardiograms in 1,935 of 2,212 (87%) American Indian Strong Heart Study participants, without mitral regurgitation or segmental left ventricular (LV) dysfunction, in Arizona, Oklahoma, and South/North Dakota. The subjects ranged widely in age (48 to 81 years) and body mass index (17.0 to 62.6 kg/m2); 65% were women; 1,161 were normotensive and 774 were hypertensive. As a reference standard, LV and stroke volumes were calculated from LV internal dimensions by the Teichholz method. Doppler SVs were moderately related to LV SVs (r = 0.63), but Doppler SV was slightly lower in both normotensive (mean = 69.8 and 72.9 mL, respectively) and hypertensive subjects (71.1 v 73.6 mL). Aortic stroke distance was less closely related than was aortic annular area to LV SV (r = 0.34 v 0.40, P < .001). Aortic annular area (r = 0.44) but not stroke distance (r = 0.04) was moderately correlated with body surface area. Stroke distance was inversely related to annular area (r = -0.29) and in subjects stratified by aortic annular diameter 1.6 to 1.9, 2.0 to 2.1, and 2.3 to 2.9 cm, mean LV SV increased from 67 to 74 to 80 mL, but average stroke distance fell from 22.8 to 21.6 to 20.1 cm. Stroke distance also failed to identify gender differences in LV SV but did identify that due to obesity. Thus Doppler SV closely parallels independently measured LV SV but slightly underestimates SV in both normotensive and hypertensive adults, whereas aortic stroke distance yields misleading comparisons between genders or individuals of different body sizes.

Epidemiology of alcohol use in a group of older American Indians

PURPOSE

This study describes alcohol use in a group of older American Indians and the associations with demographic and health status characteristics, by gender.

METHODS

Alcohol use was examined in a cross-sectional, population-based study of 161 American Indians, aged 45-76 years (a substudy of the Strong Heart Study). Alcohol use was measured by a questionnaire administered during a personal interview. Information about demographic characteristics and health status was ascertained from interviews and abstraction of medical records.

RESULTS

A higher proportion of men than women had used alcohol heavily (71% vs. 28%). Men were more likely than women to drink currently (46% vs. 18%), to binge (26% vs. 5%), and to screen positive for alcoholism (77% vs. 43%). Among current drinkers, > 30% had diabetes, and the average score on the Short Michigan Alcoholism Screening Test (SMAST) was in the alcoholic range. Heavy drinking was associated with more symptoms of depression in women (P < 0.05) and fewer in men (P < 0.05). Alcoholism was positively associated with a history of heavy drinking in both men (P < 0.05) and women (P < 0.001).

CONCLUSIONS

Alcohol use was common and varied by gender. Alcohol use also varied according to other sociodemographic and health status characteristics. Since many older American Indians with chronic illness are currently drinking, this age group may require enhanced alcohol control programs.

The prevalence of diabetic retinopathy and associated risk factors among Sioux Indians

OBJECTIVE

To estimate the prevalence of and risk factors for diabetic retinopathy among Sioux Indians of South Dakota.

RESEARCH DESIGN AND METHODS

Strong Heart Study (SHS) participants with diabetes who are members of the Cheyenne River Sioux Tribe and the Oglala Sioux Tribe were invited to have ophthalmological examinations in 1991. A total of 417 people had eye examinations out of the 488 diabetic SHS participants of the two tribes (85% participation rate). Fundus photographs were obtained of each eye and graded for severity of retinopathy using the modified Airlie House Classification Scheme. Risk factors for retinopathy were determined from the SHS database.

RESULTS

The prevalence of diabetic retinopathy among participants from these tribes was 45.3%. Risk factors associated with severity of retinopathy include mean fasting glucose, level. HbA1c, systolic blood pressure, urinary albumin-to-creatinine ratio, renal dialysis, and duration of diabetes.

CONCLUSIONS

The prevalence of diabetic retinopathy among diabetic Sioux Indians is similar to or higher than the prevalence in other diabetic Indian and non-Indian populations. Aggressive glycemic and blood pressure control is urgently needed to reduce this high rate, and annual eye examinations to detect and treat diabetic retinopathy should be emphasized.

Psychosocial barriers to health promotion in an American Indian population

Northern Plains Indians (N = 200) completed the Indian Specific Health Risk Appraisal and measures assessing beliefs about risk factors and personal risk. Participants rated personal risk optimistically, judged their risk factor standing as superior to that of their peers, and neglected to consider risk factor standing when appraising personal risk. Moreover, participants were often not improving their standing on risk factors they considered relevant to their health. Such biases in health beliefs may prevent health interventions from being successful.

Major electrocardiographic abnormalities among American Indians aged 45 to 74 years (the Strong Heart Study)

As part of the Strong Heart Study assessment of prevalent cardiovascular disease in middle-aged to elderly American Indians, the prevalence of major Minnesota code electrocardiographic (ECG) abnormalities was assessed in 4,531 participants aged 45 to 74 years (59% women) in selected tribal communities in Arizona, South and North Dakota, and Oklahoma. The overall prevalence of major ECG abnormalities was lowest in Arizona participants, (e.g., definite ECG myocardial infarction in 0.3% vs 1.8% in the other centers), although nearly two thirds of them had diabetes. One or more major ECG abnormality occurred in progressively more women (10.4% to 21.2%) and men (13.3% to 32%) (both p < 0.0001) from 45- to 54- to 55- to 64- and 65- to 74-year age groups, with the latter prevalence rates exceeding those in predominately white age peers in the Cardiovascular Health Study. Diabetes in women, but not in men, and hypertension in both genders showed positive associations with prevalence rates of major ECG abnormalities compatible with coronary artery disease or hypertensive cardiac hypertrophy. Hypercholesterolemia was not associated with ECG abnormalities except for definite myocardial infarction in women. In conclusion, major ECG abnormalities are common in middle-aged to elderly American Indians ,consistent with recent documentation of higher cardiovascular mortality in this population than in similar aged U.S. whites.

Guidelines for prevention and control of hepatitis A in American Indian and Alaska Native communities

The Aberdeen Area Indian Health Service, South Dakota Department of Health, and the Centers for Disease Control and Prevention have collaborated since 1985 to investigate hepatitis A in Indian communities in the Northern Plains and to implement clinical trials of hepatitis A vaccine. After licensure of the hepatitis A vaccine in February 1995, community wide immunization programs have been implemented effectively in several communities experiencing hepatitis A outbreaks. The state health department, tribal health departments, Indian Health Service facilities, Head Start programs and schools have provided hepatitis A immunizations to children aged 2-12 years in each of these communities after obtaining parental consent. Culturally-specific educational materials were developed and extensive health education efforts were provided by IHS and tribal programs. Hepatitis A contacts age 2-12 were offered the hepatitis A vaccine at the same time they were offered passive immunization with immune globulin. To date over 70% of parents contacted by letter or in person have returned consent forms to have their children immunized. Higher response rates were obtained in communities where home visits were made to explain this program in more detail. The outbreaks appear to have stopped after 70% or more of the children aged 2-12 years were immunized. Immunization programs are being implemented in all Northern Plains Indian communities utilizing hepatitis. A vaccine from the Vaccine For Children Program. These efforts will likely eliminate hepatitis A as a health problem for Indian communities.

Apolipoprotein E polymorphism in American Indians and its relation to plasma lipoproteins and diabetes. The Strong Heart Study

Apo E is an important genetic factor in the development of cardiovascular disease, which is the leading cause of death among American Indians. We investigated the occurrence of the apo E alleles and the relation between apo E polymorphism and blood lipoproteins and apoproteins in members of 13 American Indian communities in three geographic areas. The frequencies of the epsilon 2 alleles in American Indians are significantly lower than those in white Americans, with the lowest frequencies of epsilon 2 in American Indians who reside in Arizona. Levels of LDL cholesterol and apo B were highest in those with epsilon 4 and lowest in those with epsilon 2. Concentrations of HDL cholesterol and apo A-I, however, tended to be lowest in epsilon 4 and highest in epsilon 2. Concentrations of total and VLDL triglycerides were lowest in the epsilon 3 group and higher in groups epsilon 2 and epsilon 4. Differences in concentrations of LDL cholesterol, HDL cholesterol, apo B, and apo A-I with apo E polymorphism were greater in women than in men, and differences in total and VLDL triglyceride concentrations by apo E phenotype were greater in men. Relations of total and VLDL triglycerides with apo E phenotype were stronger in women after menopause. In addition, differences in nearly all lipid and apoprotein concentrations between postmenopausal women and premenopausal women were greater if they had epsilon 2. Relations between apo E phenotype and lipoproteins were seen in individuals with diabetes mellitus as well as in nondiabetics. Apo E was significantly related to glucose control in diabetic women; those with epsilon 3 had higher glucose and hemoglobin A1C concentrations. Our findings show that (1) American Indians have low frequencies of apo epsilon 2; (2) apo E phenotype can influence levels of VLDL, LDL, HDL, apo B, and apo A-I; (3) the associations of apo E polymorphisms with lipid parameters differ between men and women; and (4) the associations in women of apo E polymorphisms with lipid parameters are modified by menopausal status.

Plasma lipids and lipoprotein concentrations among American Indians: comparison with the US population

Lipoprotein measurements from the Third National Health and Nutrition Education Survey were used to estimate the need to measure fasting lipid concentrations and offer dietary and drug interventions in the US population. In this review, we compare the distribution of the Third National Health and Nutrition Education Survey population (according to National Cholesterol Education Program guidelines) with a contemporary sample of lipoprotein measurements in 4549 American Indians. Compared with data from the former, relatively fewer American Indians have cholesterol levels greater than 240 mg dl-1 and a much larger proportion have 'desirable' cholesterol levels less than 200 mg dl-1. The above guidelines, dictating measurement of fasting lipoprotein concentrations and dietary or drug intervention, take into account age, presence of cardiovascular risk factors and levels of both HDL- and LDL-cholesterol. The proportion of American Indians requiring these interventions is somewhat at less than the Third National Health and Nutrition Education Survey population, even though the American Indian population in this comparison is generally older (45-74 years of age) than the Survey participants (20 to more than 75 years of age). We review the literature concerning lipoprotein measurements in other American Indian and ethnic population groups that are undergoing rapid changes in lifestyle. In general, cardiovascular risk factors, including lipoprotein concentrations, are accumulating. These factors suggest that the public health impact of coronary heart disease will increase as these populations undergo further lifestyle changes.

Hypertension in adult American Indians. The Strong Heart Study

Hypertension is a primary risk factor for cardiovascular disease in the United States. Although cardiovascular disease is the leading cause of death among American Indians, the prevalence of hypertension, its awareness and control, and its association with other cardiovascular disease risk factors and physiological variables have not been well studied in this population. The Strong Heart Study is a longitudinal study of cardiovascular disease and its risk factors in American Indians. Participants (2703 women and 1846 men) were members of 13 tribes in central Arizona, southwestern Oklahoma, and regions of South and North Dakota. At least 1500 individuals between 45 and 74 years of age participated from each center in a baseline clinical examination conducted between July 1989 and January 1992. The examination consisted of a personal interview and physical examination that included an oral glucose tolerance test and three consecutive blood pressure measurements. This study reports data from the baseline examination on the prevalence of hypertension and correlates of blood pressure. Results indicated that despite the high frequency of diabetes and obesity, prevalence rates of hypertension in Arizona and Oklahoma were similar to those in the US population in the Third National Health and Nutrition Examination Survey (NHANES III), and rates among South/North Dakota participants were significantly lower (P < .0001). Blood pressure was higher in individuals with diabetes (P < .0001) and was significantly correlated with age (P < .0001) and albuminuria (P < .0001) but only weakly related to obesity. There was no independent relation between blood pressure and insulin. Blood pressure seems to be less affected by obesity and hyperinsulinemia in American Indians compared with other populations. Nevertheless, hypertension should be aggressively treated and controlled in American Indians because it is a known precursor to morbidity and mortality associated with diabetes and cardiovascular disease.

Diabetes and coronary heart disease in American Indians: The Strong Heart Study

Coronary heart disease (CHD) is the leading cause of death among American Indians. However, information on the prevalence of CHD and its association with known risk factors is limited. The purpose of the Strong Heart Study is to quantify CHD and its risk factors among three geographically diverse groups of American Indians. The population consists of 4,549 adults between 45 and 74 years of age in 13 Indian communities in Arizona, Oklahoma, and South and North Dakota. The phase I examination (1989-1991) revealed very high prevalence rates of diabetes that ranged from 33 to 72% in men and women in the three centers. Prevalence rates of definite myocardial infarction (MI) and definite CHD were higher in men than in women in all three centers (P < 0.0001) and in those with diabetes (P = 0.002 and P = 0.0003 in women and men respectively). Diabetes was associated with a relatively greater increase in prevalence of MI (prevalence rate = 3.8 vs. 1.9) and CHD (prevalence rate = 4.6 vs. 1.8) in women than in men. Logistic regression analysis indicated that the prevalence of CHD among American Indians was significantly related to age, diabetes, hypertension, albuminuria, percentage of body fat, smoking, high concentrations of plasma insulin, and low concentrations of HDL cholesterol. Lower prevalence rates of CHD were found in Arizona despite higher rates of diabetes, obesity, hypertension, and albuminuria; these lower rates may be in part related to lower smoking frequency and lower concentrations of total and LDL cholesterol. These findings from the baseline Strong Heart Study examination emphasize the relative importance of diabetes and its associated variables as risk factors for CHD among American Indian populations.

Along for the ride: the prevalence of motor vehicle passengers riding with drivers who have been drinking in an American Indian population

American Indians, especially those residing in the Northern Plains, experience considerable preventable morbidity and mortality from alcohol-related motor vehicle events. Research focusing on unintentional injuries associated with drinking drivers has disregarded the epidemiology of their passengers, who are equally at risk. The purpose of this investigation was to define the prevalence of motor vehicle passengers riding with drivers who have been drinking on a Northern Plains Reservation. We surveyed a sample of 151 Northern Plains Indians about their experiences riding with drinking drivers. Associated behavioral and demographic risk factors were also examined to identify possible predictor variables. The majority (54%) of respondents reported riding with a driver who had been drinking at least once during the previous three months. Most often, passengers ride with a friend who has been drinking, on a weekend night. Injury risk may be compounded because few respondents reported regular seat-belt use. The results off our study suggest the need for immediate comprehensive prevention efforts focusing on motor vehicle passengers.

Cardiovascular disease risk factors among American Indians. The Strong Heart Study

The Strong Heart Study, a study of cardiovascular disease among American Indians, was conducted to determine cardiovascular disease rates and the prevalence of risk factors among members of 13 tribal groups in South Dakota/North Dakota (SD/ND), southeastern Oklahoma, and Arizona. From 1989 to 1992, 4,549 tribal members aged 45-74 years (62% of eligible participants) were surveyed and examined for cardiovascular disease and its risk factors. Mean total cholesterol concentrations were over 20 mg/dl lower among the men and 27 mg/dl lower among the women than national mean levels for the same age groups. Cholesterol levels varied by tribal group; Arizona Indians had mean levels more than 20 mg/dl lower than those of SD/ND Indians. The prevalence of hypercholesterolemia was almost twice as high among SD/ND Indians as among Arizona Indians, but the rates for all three groups were much lower than total US rates (all races). Mean levels of high density lipoprotein cholesterol were lower among Indian men and women than in the US population as a whole. The prevalence of hypertension among Arizona and Oklahoma Indians was higher than that for the entire United States. SD/ND Indians had significantly lower mean blood pressures and prevalence rates of hypertension than Oklahoma and Arizona Indians and the United States as a whole. The prevalence of cigarette smoking was higher for all Indian groups except Arizona women in comparison with US rates. Smoking rates were highest in SD/ND and lowest in Arizona. Indian smokers smoked fewer cigarettes per day than the average US smoker. Arizona Indians had the highest prevalence of diabetes mellitus; over 60% of those participants were diabetic. In Oklahoma and SD/ND, one third of the men and over 40% of the women were diabetic. In addition, 13-20% of the participants had impaired glucose tolerance. Proteinuria was also a common problem; almost half of the Arizona Indians had micro- or macroalbuminuria, and 20% of Oklahoma and SD/ND Indians had significant proteinuria. The prevalence of obesity was high in all three groups, with Arizona Indians having the highest rates and the highest mean body mass indices. The prevalence of current alcohol use was lower among Indians than in the nation as a whole, but binge drinking was common among those who used alcohol. These results indicate that cardiovascular disease risk factors vary significantly among tribal groups. Prevention programs tailored toward decreasing the prevalence of risk factors are recommended for long-term reduction of cardiovascular disease rates in American Indian communities.

Coronary heart disease prevalence and its relation to risk factors in American Indians. The Strong Heart Study

Although coronary heart disease (CHD) is currently the leading cause of death among American Indians, information on the prevalence of CHD and its association with known cardiovascular risk factors is limited. The Strong Heart Study was initiated in 1988 to quantify cardiovascular disease and its risk factors among three geographically diverse groups of American Indians. Members of 13 Indian communities in Arizona, Oklahoma, and South and North Dakota between 45 and 74 years of age underwent a physical examination that included medical history; an electrocardiogram; anthropometric and blood pressure measurements; an oral glucose tolerance test; and measurements of fasting plasma lipoproteins, fibrinogen, insulin, hemoglobin A1c, and urinary albumin. Prevalence rates of definite myocardial infarction and definite CHD were higher in men than in women at all three centers (p < 0.0001) and higher in those with diabetes mellitus (p = 0.002 in men and p = 0.0003 in women). Diabetes was associated with relatively higher prevalence rates of myocardial infarction (diabetic:nondiabetic prevalence ratio = 3.8 vs. 1.9) and CHD (prevalence ratio = 4.6 vs. 1.8) in women than in men. Prevalence rates of heart disease were lowest in the communities in Arizona; prevalence rates were similar in Oklahoma and South Dakota/North Dakota and were two- to threefold higher than those in Arizona. By logistic regression, prevalent CHD among American Indians was significantly and independently related to age, diabetes, hypertension, albuminuria, percentage of body fat, smoking, high concentrations of plasma insulin, and low concentrations of high density lipoprotein cholesterol. In contrast to reports from other non-Indian populations, diabetes was the strongest risk factor. The lower prevalence of CHD among Indians in Arizona is distinctive in view of their higher rates of diabetes, obesity, hypertension, and albuminuria, but it may be partly related to their low frequency of smoking and their low concentrations of total and low density lipoprotein cholesterol. These findings from the initial Strong Heart Study examination emphasize the importance of diabetes and its associated variables as risk factors for CHD in Native American populations.

Diabetes and impaired glucose tolerance in three American Indian populations aged 45-74 years. The Strong Heart Study

OBJECTIVE

To estimate prevalence rates of diabetes and impaired glucose tolerance (IGT) in three American Indian populations, using standardized diagnostic criteria, and to assess the association of diabetes with the following selected possible risk factors: age, obesity, family history of diabetes, and amount of Indian ancestry.

RESEARCH DESIGN AND METHODS

This cross-sectional study involved enrolled members, men and women aged 45-74 years, of 13 American Indian tribes or communities in Arizona, Oklahoma, and South and North Dakota. Eligible participants were invited to the clinic for a personal interview and a physical examination. Diabetes and IGT status were defined by the World Health Organization criteria and were based on fasting plasma glucose and oral glucose tolerance test results. Data on age, family history of diabetes, and amount of Indian ancestry were obtained from the personal interview, and measures of obesity included body mass index, percentage body fat, and waist-to-hip ratio.

RESULTS

A total of 4,549 eligible participants were examined, and diabetes status was determined for 4,304 (1,446 in Arizona, 1,449 in Oklahoma, and 1,409 in the Dakotas). In all three centers, diabetes was more prevalent in women than in men. Arizona had the highest age-adjusted rates of diabetes: 65% in men and 72% in women. Diabetes rates in Oklahoma (38% in men and 42% in women) and South and North Dakota (33% in men and 40% in women), although considerably lower than in Arizona, were several times higher than those reported for the U.S. population. Rates of IGT among the three populations (14-17%) were similar to those in the U.S. population. Diabetes rates were positively associated with age, level of obesity, amount of Indian ancestry, and parental diabetes status.

CONCLUSIONS

Diabetes is found in epidemic proportions in Native American populations. Prevention programs and periodic screening should be implemented among American Indians. Standards of care and intervention have been developed by the Indian Health Service for individuals in whom diabetes is diagnosed. These programs should be expanded to include those with IGT to improve glycemic control or to reduce the risk of development of diabetes as well as to reduce the risk of diabetic complications.

Type II diabetes and cognitive function. A population-based study of Native Americans

OBJECTIVE

To explore the relationship between type II diabetes and cognitive function in older Native Americans and to assess the effects of other selected risk factors for cognitive dysfunction on this relationship.

RESEARCH DESIGN AND METHODS

Cognitive function was assessed in 80 diabetic and 81 nondiabetic Native Americans who were 45-76 years of age in a cross-sectional population-based sub-study of the Strong Heart Study. Thirteen cognitive function tests were administered during a personal interview. Information about six other risk factors for cognitive dysfunction, including depressive symptoms, physical function, alcoholism, current alcohol use, hypertension, and myocardial infarction, was ascertained from interviews and from abstraction of medical records.

RESULTS

Diabetes was associated with impairment on only two tests of cognitive function: verbal fluency (P = 0.004) and similarities (P = 0.010). Depressive symptoms were related to verbal fluency (P = 0.004), but did not explain the diabetes-related difference in performance. The effects of hypertension, depressive symptoms, and current alcohol use explained the diabetes-related performance difference on similarities. Cognitive function was not related to metabolic control (HbA1c level).

CONCLUSIONS

We found little evidence that type II diabetes in this population of Native Americans is associated with decrement in cognitive function. Some of the cognitive impairment previously attributed to diabetes may be related, at least in part, to the influence of other risk factors. This should be considered in the design of future studies in other populations.

Cultural factors associated with health-risk behavior among the Cheyenne River Sioux

A field study was conducted to identify cultural factors--values, beliefs, and related characteristics--associated with health-risk behavior among adult members of the Cheyenne River Sioux Tribe. The Cultural Values Survey (CVS), an instrument for measuring cultural values and related characteristics, was developed and pilot tested in the study population. This instrument, along with the Health Risk Appraisal (HRA) (an instrument developed by the Centers for Disease Control to quantify major health-related behaviors), was administered to a random sample of 429 adults in the study community. Significant differences between females and males for both cultural characteristics and health-risk behaviors were found. Females had significantly higher HRA-calculated Health Index values than males, reflecting overall healthier behaviors. Females who scored higher on cultural factors consistent with more traditional Lakota Indian lifestyles (e.g., degree of Indian blood, Lakota language spoken in the home, traditional Lakota beliefs) had higher HRA Health Index values than females scoring lower in these characteristics. Males who scored higher in factors related to self-determination (e.g., hard work, personal control, industriousness, individual action) had higher Health Index values than those who scored lower in these areas. Further testing of the CVS instrument, as well as further research from both epidemiologic and social science perspectives is essential to elucidate the nature of the relationship between cultural factors and health-related behavior.

Cancer risk factors in three Sioux tribes. Use of the Indian-specific health risk appraisal for data collection and analysis

Cancer mortality rates for Aberdeen Area Indians exceed U.S. rates with lung cancer being the leading cause of cancer death. The Sioux Cancer Study, an ancillary study of the Strong Heart Study, investigated cancer and cancer risk factors among tribal members aged 45-74 in three Sioux tribes in North and South Dakota. An Indian-specific health risk appraisal was used to collect data and provide specific recommendations to participants. The high rates of smoking (56% for men and 48% for women) explain the high lung cancer mortality rates. Intensive smoking cessation and prevention programs will likely have the greatest impact in reducing preventable cancer deaths. More accessible cervical and breast cancer screening provided by female health care providers is needed to reduce preventable cancer deaths among Sioux women. Pap smear screening is an especially high priority since cervical cancer mortality is 4.4 times higher than U.S. rates, all races. Programs targeted to reduce obesity and excessive alcohol use will also likely reduce preventable cancer deaths associated with high rates of obesity, diabetes and binge drinking. Community-based cancer prevention and control programs tailored to the cancer risk factor profile of the community are the best strategy to reduce preventable cancer deaths in Indian communities.

Cardiovascular disease among American Indians and Alaska Natives

OBJECTIVE

To compare the regional differences in cardiovascular disease in AI/AN with the U.S. general population and determine the parity gap and preventable proportion of cardiovascular mortality.

RESEARCH DESIGN AND METHODS

Age-adjusted cardiovascular disease mortality rates for 1981-1983 and hospital discharge rates for 1982-1984 reported by the IHS were compared with U.S. data for 1982 and 1983, respectively.

RESULTS

Rates of ischemic heart disease and atherosclerosis were found to be generally low among AI/AN although those in the 25- to 44-yr age-group have higher death rates from cardiovascular disease than in the U.S. population. Although the mortality rate from cardiovascular disease in AI/AN is 19% lower than the rate for the general U.S. population, the parity gap in individual regions of the U.S. ranges from favorable to extremely unfavorable. There were also wide variations in the preventable gap theoretically possible by reduction of the three major risk factors.

CONCLUSIONS

Changing nutrition and exercise patterns and the increasing prevalence of diabetes in many Indian tribes may have adverse effects in the future, possibly increasing the prevalence of heart disease. Regional differences in the prevalence of some major cardiovascular risk factors (smoking, hypertension, hypercholesterolemia, and diabetes) are the probable explanation for these differences in cardiovascular morbidity and mortality rates. Prevention and treatment of these risk factors will have the greatest impact in attempts to reduce cardiovascular disease among AI/AN. In addition, moderation in the use of alcohol, or abstinence, may prevent sudden deaths resulting from acute intoxication.

Risk factors for coronary heart disease in diabetic and nondiabetic Native Americans. The Strong Heart Study

The Strong Heart Study is a study of cardiovascular disease and its risk factors among diabetic and nondiabetic Native Americans. The study includes 12 tribes in Arizona, Oklahoma, and North and South Dakota. Phase I, initiated in October 1988, included a mortality survey to determine CVD death rates in individuals 35-74 yr old between 1984 and 1988, and a medical record review to determine rates of myocardial infarction and stroke for individuals ages 45-74 during the same time. In addition, a physical examination was performed on persons 45-74 yr old to measure the prevalence of cardiovascular and peripheral vascular diseases and known and suspected risk factors. In Phase II, CVD mortality and morbidity rates will be determined in the examined cohort by surveillance. CVD risk factors, changes in risk factors over time, and the relationship between risk factors and CVD incidence will be assessed longitudinally. This study provides data on the relative importance of cardiovascular risk factors in nondiabetic and diabetic Native Americans and will provide insight into possible variations in the quantitative or qualitative importance of CVD risk factors among diverse population groups.

The benefits of isoniazid chemoprophylaxis and risk factors for tuberculosis among Oglala Sioux Indians

In a case-control study of 92 Indian patients, 46 with active tuberculosis (cases) and 46 tuberculin reactors without the disease (control subjects), significantly more control subjects than patients had prior adequate isoniazid chemoprophylaxis. While the Indian Health Service recommends treating all tuberculin reactors with isoniazid prophylaxis, most (75%) of our tuberculosis (TB) cases could have been prevented if the guidelines of the American Thoracic Society had been followed. Diabetes, alcohol abuse, and chronic renal failure were risk factors for active TB. Despite marked reductions in TB morbidity and mortality rates among American Indians and Alaska Natives over the past 30 years, their TB rates are still two to three times higher than overall United States and white rates. Enhanced TB control programs with an emphasis on preventive therapy for patients at risk for developing active disease, especially those with diabetes and chronic renal failure, could decrease the incidence and eventually eliminate TB among American Indians and Alaska Natives.

Health implications of obesity in American Indians and Alaska Natives

American Indians and Alaska Natives (AI/ANs) are experiencing an epidemic of diabetes, increasing rates of coronary artery disease and hypertension, and poor survival rates for breast cancer that are likely partially attributable to the increasing prevalence of obesity over the past generation. Obesity may also contribute to the high rates of gallstones and to adverse outcomes of pregnancy in AI/ANs. Although overall mortality was not associated with obesity in Pima Indians (except in the most obese men), the relationship of obesity to longevity in other AI/AN groups is not known. Further study of the specific health effects of obesity in various groups of AI/ANs are needed. In the meantime, community-based programs to prevent obesity and its sequelae should be implemented in all AI/AN communities.

The Strong Heart Study. A study of cardiovascular disease in American Indians: design and methods

Available data indicate that cardiovascular disease has become the leading cause of death in American Indians. However, limited information is available on cardiovascular disease incidence, prevalence, and risk factors in this population. Reported cardiovascular disease rates vary greatly among groups in different geographic areas. These rates have been obtained from studies of varying sizes and different methodologies. The Strong Heart Study, which uses standardized methodology, is designed to estimate cardiovascular disease mortality and morbidity rates and the prevalence of known and suspected cardiovascular disease risk factors in American Indians. The study population consists of 12 tribes in three geographic areas: an area near Phoenix, Arizona, the southwestern area of Oklahoma, and the Aberdeen area of North and South Dakota. The study includes three components. The first is a mortality survey to estimate cardiovascular disease mortality rates for 1984-1988 among tribal members aged 35-74 years, and the second is a morbidity survey to estimate incidence of both first and first or recurrent hospitalized myocardial infarction and stroke (cerebrovascular disease) among tribal members aged 45-74 years in 1984-1988, and the third is a clinical examination of 4,500 tribal members aged 45-74 years in order to estimate the prevalence of cardiovascular disease and its associations with risk factors. Family history, diet, alcohol and tobacco consumption, physical activity, degree of acculturation, and socioeconomic status are assessed in personal interviews. The physical examination includes measurements of body fat, body circumferences, and blood pressure, an examination of the heart and lungs, an evaluation of peripheral vascular disease, and a 12-lead electrocardiogram. Laboratory measurements include fasting and postload glucose, insulin, fasting lipids, apoproteins, fibrinogen, and glycated hemoglobin. Also measured are serum and urine creatinine and urinary albumin. DNA from lymphocytes is isolated and stored for future genetic studies.

The expected impact of a smoking cessation program for pregnant women on infant mortality among Native Americans

To quantify the expected impact of a smoking cessation program for pregnant women on infant mortality among Native Americans, we estimated the proportional reduction (impact fraction) and the absolute reduction (impact risk) in neonatal and postneonatal mortality as a result of the intervention program. The estimated attributable fraction due to maternal smoking was 16.6% of infant deaths in the Aberdeen Indian Health Service (IHS) Area, 16.2% in the Alaska IHS Area, and 5.2% in the Navajo IHS Area. Under the assumptions that 14% of the smokers participating in a smoking cessation program would quit and that the intervention would have 60% relative efficacy in preventing infant deaths attributable to smoking, the impact fraction was estimated to be 0.9% of all infant deaths in the Aberdeen Area, 1.0% in the Alaska Area, and 0.3% in the Navajo Area. Under the "best" model assumptions (28% cessation rate and 90% relative efficacy), 2.6% of all infant deaths, 3.7% of postneonatal deaths, and 1.2% of neonatal deaths would be prevented by a smoking cessation program in the Aberdeen Area. When applied to 1984-1986 infant mortality data, the impact risk per 100,000 live births under the "best" model assumptions was 10 neonatal deaths and 41 postneonatal deaths in the Aberdeen Area, 10 neonatal and 34 postneonatal deaths in Alaska, and 2 neonatal and 8 postneonatal deaths in the Navajo Area. This report points to the need to develop effective smoking cessation programs for Native Americans, targeted in particular to women of reproductive age.

Hepatitis transmission among the Sioux Indians of South Dakota

Hepatitis A continues to occur in cyclical community-wide epidemics on the Indian reservations of South Dakota. In June 1985 a population-based serosurvey for viral hepatitis involving 120 households was conducted at the Pine Ridge and Rosebud Sioux Indian reservations in South Dakota. The serosurvey was performed shortly after a large hepatitis A epidemic on the Pine Ridge reservation in 1983-84, and immediately before a large hepatitis A epidemic on the Rosebud reservation in 1985-86. The overall seroprevalence for antibodies to hepatitis A virus (anti-HAV) was 76.2 percent (Pine Ridge reservation 80.5 percent, Rosebud reservation 72.0 percent, relative risk = 1.12, 95 percent confidence interval = 1.01, 1.24). For age groups 0 to 4 years, 54.2 percent and 36.1 percent of children were seropositive at Pine Ridge and Rosebud, respectively. Seropositivity rose rapidly with age; by age 40, more than 90 percent of persons at both Pine Ridge and Rosebud were anti-HAV positive. Only 1.1 percent of persons tested were positive for hepatitis B markers. Anti-HAV seroprevalence rates in both communities are similar to rates observed in developing countries. The surprisingly high anti-HAV seroprevalence among young children at Rosebud, where clinical hepatitis A had been virtually absent in the previous seven years, indicates that high-grade silent transmission was taking place during the interepidemic period.

Sudden unexplained infant deaths among American Indians and whites in North and South Dakota

Differences in risk factors for sudden unexplained infant death (SUID) were studied among American Indian and White infants in North and South Dakota. From 1977 to 1984, the incidence of SUID was 3.9 times higher among Indians compared with Whites. Indian SUID cases appeared to die at a slightly younger age than Whites, and the association of male gender and young maternal age with SUID was weak or absent among Indians. Low maternal education and late or no prenatal care were strongly related to SUID in both races. The Indian-White risk ratio was unaltered by adjustment for birthweight and maternal age but declined to 2.5 (95% confidence intervals = 1.9, 3.4) when adjusted for maternal education and trimester prenatal care began.

Determinants of blood pressure in Navajo adolescents

Hypertension is becoming more common among Navajo people, especially among young men. In a group of 580 Navajo adolescents, we looked for factors associated with variations in blood pressure level. Using our criteria, 11.1% of adolescent males and 1.6% of females had an elevated screening blood pressure. In males, blood pressure was a function of age only, and not significantly related either to obesity (body mass index) or measures of acculturation and personal adjustment. In females, blood pressure was not related to age, but was associated with body mass index. Systolic pressure in females was also associated with poor personal adjustment. Level of acculturation (by our index) had no bearing on blood pressure level in this population.

Acute myocardial infarction and sudden death in Sioux Indians

While some Indian tribes have low rates of acute myocardial infarction, Northern Plains Indians, including the Sioux, have rates of morbidity and mortality from acute myocardial infarction higher than those reported for the United States population in general. In a review of diagnosed cases of acute myocardial infarction over a 3-year period in 2 hospitals serving predominantly Sioux Indians, 8% of cases were found misclassified, and 22% failed to meet rigorous diagnostic criteria, although the patients did indeed have ischemic heart disease. Patients had high frequencies of complications and risk factors and a fatality rate of 16% within a month of admission. Sudden deaths likely due to ischemic heart disease but in persons not diagnosed as having acute myocardial infarction by chart review occurred 3 times more frequently than deaths occurring within a month of clinical diagnosis.

Complete culture medium is better than low folate medium for detecting increased chromosome aberrations in smokers in 48-h lymphocyte cultures

We compared chromosome breakage in parallel, 48-h lymphocyte cultures established from smokers and nonsmokers using minimal essential medium (MEM) and MEM without folate (MEM-FA). There was a statistically significant, higher frequency of aberrations for smokers than for nonsmokers in cells cultured in MEM, but not in those cultured in MEM-FA. Thus, these data support the recommendation of the World Health Organization (1985) that population monitoring studies for exposure assessment should not use a low folate medium.

Increased sister chromatid exchange associated with smoking and coffee consumption

Sister chromatid exchange (SCE) is a very sensitive cytogenetic assay for detecting exposure to chemical mutagens and carcinogens. One application of SCE is the monitoring of populations believed to be exposed to such agents. We have, however, relatively little knowledge about common lifestyle factors that may influence SCE and therefore complicate any study designed to examine the effects of exposure to genotoxins. In this study, we assessed the effect of cigarette smoking and coffee consumption on SCE. Smoking was associated with an increase of approximately 2 SCEs per cell and a decrease in cell proliferation. A positive linear relationship between SCE and coffee consumption was also observed. This effect was similar for smokers and nonsmokers. Additionally, the folic acid content of cell culture medium seemed to affect neither SCE nor cell proliferation.

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.

Plague

Successful treatment of plaque depends on early diagnosis, institution of effective antibiotics (streptomycin, chloramphenicol, tetracycline or gentamicin) and adequate supportive care. To reduce mortality, therapy should be started in patients suspected of having plague while diagnostic procedures are under way. If persons with acute febrile illness (especially regional lymphadenitis) have been in plague-endemic areas within the week preceding the onset of illness, the diagnosis of plague should be considered.

Acute myocardial infarction among Navajo Indians, 1976-83

We found that from 1976 through 1983 the incidence of acute myocardial infarction (AMI) diagnosed among Navajo Indians remained low (0.5 per 1,000 persons age 30 years or more), although the incidence in women appears to be climbing. Navajo AMI patients are more likely to be hypertensive and diabetic than age- and sex-matched patients with gallbladder disease. Twenty-four per cent die within one month of AMI.

Effects of exposure to salty drinking water in an Arizona community. Cardiovascular mortality, hypertension prevalence, and relationships between blood pressure and sodium intake

A high level of sodium (440 mg/L) in the water supply of Gila Bend, Ariz, caused concern because of apparently elevated rates of hypertension in Gila Bend Papago Indians. We surveyed 342 Gila Bend Papago Indians and 375 non-Indians from July to September 1983. Participants 25 years of age and older were interviewed for health risk factors, water consumption, and dietary sodium and calcium intake and had height, weight, blood pressure, and urinary sodium and potassium levels measured. No consistent associations were found between any of the sodium values and systolic or diastolic blood pressure. Mean blood pressures for the Gila Bend whites were lower in most age groups than in comparison US white populations. The prevalence rates of hypertension in Gila Bend were not significantly higher than national rates.

Nineteen cases of plague in Arizona. A spectrum including ecthyma gangrenosum due to plague and plague in pregnancy

We review the cases of 19 successfully treated plague patients, with emphasis on the clinical and epidemiologic features of the disease. Proper staining and culturing of bubo aspirates; prompt institution of streptomycin, chloramphenicol or tetracycline therapy in presumptive cases, and supportive care are the crucial factors in the treatment of plague. This disease should be considered in patients in a toxic condition who have lymphadenitis, pneumonia or septic shock and who have been in endemic areas within the past ten days.

Epidemiology of Haemophilus influenzae type B disease among Navajo Indians

During a 7-year period ending June 30, 1980, the annual incidence of all Haemophilus influenzae type b disease among Navajo children less than 5 years old was 214 per 100,000, and that of H. influenzae meningitis was 152 per 100,000. Eighty-one percent of H. influenzae meningitis occurred in children 12 months of age or younger, and 64 percent clustered in children ages 4 through 8 months. Meningitis accounted for 70 percent of all invasive disease. No epiglottitis was observed. The epidemiology is similar to that in Yupik Eskimos, who have an even higher rate of H. influenzae type b disease than Navajos but are a much smaller population. Mortality from H. influenzae meningitis was low (4 percent) among Navajo children, but neurological sequelae were observed in at least 16 percent of the survivors. This high rate of sequelae may be due in part to clustering of cases in infancy. Among normal Navajo neonates, 79 percent had maternal capsular type b antibody titers greater than or equal to 0.15 micrograms per deciliter (microgram per dl), and the whole group had a geometric mean titer of 0.51 micrograms per dl. By age 4 months, when meningitis cases became frequent, only 14 percent of Navajo infants had antibody titers greater than or equal to 0.15 micrograms per dl. Twelve of 67 asymptomatic infants (18 percent), each monitored every 2 months, had H. influenzae type b or a cross-reacting organism isolated from the pharynx on at least one occasion before they were 9 months old. Active immunization would be theoretically indicated in this population with high H.influenzae type b exposure and disease, but a vaccine would have to confer substantial immunity in very young infants.

Immunogenicity of a Haemophilus influenzae type b vaccine in combination with diphtheria-pertussis-tetanus vaccine in infants

Seventy-eight Navajo infants (one to two months of age) were randomly assigned to one of two vaccination groups: one group (40 infants) was scheduled to receive three doses of diphtheria-pertussis-tetanus (DPT) vaccine and the other (38 infants) to receive DPT combined with Haemophilus influenzae type b polyribosyl-ribitol phosphate (DPT + PRP vaccine). In the latter vaccine, pertussis antigen served as an adjuvant for PRP. Sixty-seven infants (37 who received DPT vaccine and 30 who received DPT + PRP vaccine) completed the protocol. Local and systemic reactions were equally frequent in the two groups. Fifty percent of the infants who received DPT + PRP vaccine had definite antibody responses to PRP after three doses, and 13% had possible responses. Of the infants who received DPT vaccine, 14% and 8% had definite and possible responses, respectively; three of five infants with definite responses were infected with H influenzae type b or cross-reacting organisms, as determined by pharyngeal cultures. The immune response did not appear to be suppressed by the presence of maternal antibody.

Gasoline sniffing and lead toxicity in Navajo adolescents

During a 6-year period, 23 Navajo adolescents were hospitalized 47 times for presumed lead intoxication secondary to gasoline sniffing. Most patients were male (87%) and sniffed gasoline as a social activity, more frequently in spring and summer. Sixty-five percent of the patients first presented with toxic encephalopathy. Of total episodes, 31% involved asymptomatic lead overload; 31% involved tremor, ataxia, and other neurologic signs; and 38% involved encephalopathy with disorientation and hallucinations. Free erythrocyte protoporphyrin levels were not consistently high, although blood lead levels were all elevated. One death occurred. Approximately 11% of 537 Navajo adolescents said they inhaled gasoline for enjoyment at least occasionally. Among 147 junior high school students, blood lead levels averaged 18 +/- 6 micrograms/dL with no values greater than 40 micrograms/dL. Three of these students had elevated zinc protoporphyrin levels and all three were anemic. No correlation was found between levels of blood lead or zinc protoporphyrin and whether or not the youth reported sniffing gasoline. However, sniffing gasoline was associated with poor school performance and delinquent behavior. Although apparently many Navajo adolescents experiment with gasoline inhalation, only a few engage in this activity frequently enough to develop either asymptomatic or symptomatic lead overload.

Cost-benefit of a streptococcal surveillance program among Navajo Indians

A school-based streptococcal surveillance program has been in effect among Navajo Indians for more than 4 years. Throat cultures of symptomatic children are obtained when indicated, and routine throat cultures are performed monthly. Children whose cultures are positive for group A beta-hemolytic streptococci are treated. During 4 academic years, between 48 percent and 56 percent of elementary school children attended the schools that had 4 or more monthly surveys in each year, but only 24 percent (7 of 29) of the acute rheumatic fever (ARF) cases occurred in children at those schools. Six of seven children attending covered schools were not cultured before their ARF episodes. Five cases occurred in children attending previously covered schools, during years in which participation lapse. Three or four ARF cases per year appeared to have been prevented, but the program's costs were five times the estimated costs of the prevented cases, even excluding risks of allergic reactions to penicillin. There is little evidence that most asymptomatic carriers are at risk to develop ARF. The authors recommend that streptococcal surveillance efforts be confined largely to culturing throat swabs of children with pharyngitis.

Bacterial meningitis in Navojo Indians

An analysis of 219 confirmed cases of bacterial meningitis among Navajo Indians during a 5-year period, July 1, 1968, through June 30, 1973, revealed that 56 percent were caused by Haemophilus influenzae, 26 percent by Neisseria meningitidis, 6 percent by Mycobacterium tuberculosis, and 6 percent by other organisms. The annual incidence of H. influenzae meningitis (17.7 per 100,000 persons) and that of pneumococcal meningitis (8.0 per 100,000) were much higher than the rates for these diseases reported from other population groups. The annual incidence of meningococcal meningitis (2.0 per 100,000) was similar to that found elsewhere. There was an ususual concentration of cases during the first year of life; 78 percent of H. influenzae, 64 percent of pneumococcal, and 50 percent of meningococcal meningitis occurred during this time. However, bacterial meningitis during the first month of life was not frequent (0.29 per 1,000 live births). Case fatality rates were similar to those reported for other population groups.