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Biomedical subjects

B V Howard

Publications and source records attributed to B V Howard.

At least 91 records · Page 5Linked to original sources
PubMed1996

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.

Adult↗
PubMed1996

Estimation of left ventricular chamber and stroke volume by limited M-mode echocardiography and validation by two-dimensional and Doppler echocardiography.

This study has been designed to improve estimation of stroke volume from linear left ventricular (LV) dimensions measured by M-mode echocardiography, in symmetrically contracting ventricles. In experimental studies, the ratio of LV epicardial long/short axes "Z" is about 1.3. We measured systolic and diastolic epicardial long and short axes by 2-dimensional echocardiography in 115 adults with widely varying LV short-axis dimensions (LV end-diastolic dimension = 3.95 to 8.3 cm). In a learning series of 23 normotensive and 27 hypertensive subjects, Z(diastole) was 1.3 +/- 0.1 and Z(systole) = 1.2 +/- 0.1, similar to findings in experimental animals. Regression equations were developed by comparing LV volumes by M-mode and 2-dimensional echocardiography. In a test series (65 subjects), LV volumes were calculated using separate regression equations for end-diastolic volume ([LV end-diastolic dimension] 4.765 - 0.288 x posterior wall thickness]) and for end-systolic volume ([LV end-systolic dimension] [4.136 - 0.288 x posterior wall thickness]). Because the term 0.288 x wall thickness was only about 8% of the first term between brackets, the average wall thickness in the learning series was substituted in the Z-volume formulas applied to the test series: end-diastolic volume = (4.5 x [LV end-diastolic dimensions]2) and end-systolic volume = (3.72 x [LV end-diastolic dimension]2). The mean relative error produced with this simplified method was 0.9%. in diastole and 1.4% in systole. Compared with Teichholz' M-mode volume method, Z-derived end-diastolic volume in the test series was equally well related to 2-dimensional volumes (both r = 0.88), with a better intercept (1.5 vs -23 ml, p <0.001) and a slope closer to the identity line (1.1 vs 1.4). Similar results were found for systolic volumes. In a second test series of 1,721 American Indian participants in the Strong Heart Study without mitral regurgitation or segmental LV wall motion abnormalities, Doppler-derived LV stroke volume (70 +/- 14 ml/beat) was similarly predicted by the Z-derived method (r = 0.65, 70 +/- 11 ml/beat) and Teichholz formulas (r = 0.64, 72 +/- 13 ml/beat), but Z-derived volumes had a regression line significantly closer to the identity line (p <0.005). Thus, LV chamber and stroke volumes can be determined from M-mode LV diameters over a wide range of LV sizes and in epidemiologic as well as clinical populations. The performance of this new method appears better than that obtained using the Teichholz formula, with a formula that is easy to handle and makes calculation of LV volumes by pocket calculator possible, even from limited echocardiographic studies.

Adult↗
PubMed1996

Adverse effect of pregnancy on high density lipoprotein (HDL) cholesterol in young adult women. The CARDIA Study. Coronary Artery Risk Development in Young Adults.

The authors analyzed data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study in order to examine associations between parity and lipoproteins. Of 2,787 women recruited in 1985-1986, 2,534 (91%) returned in 1987-1988 and 2,393 (86%) returned in 1990-1991 for repeat evaluations. Two-year change (1987-1988 to 1985-1986) in high density lipoprotein (HDL) cholesterol was significantly different among the parity groups. HDL cholesterol decreased in women who had their first pregnancy of at least 28 weeks duration during follow-up (mean +/- standard error, -3.5 +/- 1.2 mg/dl), and this change was significantly different from the increase in women parous at baseline who had no further pregnancies (2.5 +/- 0.3 mg/dl) and in nullipara (2.4 +/- 0.3 mg/dl). There was a nonsignificant trend for a greater decrease in HDL2 cholesterol fraction in the primipara compared with the other groups. The HDL cholesterol decrease remained significant after controlling for race, age, education, oral contraceptive use, and changes in body mass index, waist-hip ratio, physical activity, smoking status, and alcohol intake. Change in HDL cholesterol was also significantly different among the parity groups in analyses of pregnancies that occurred during the subsequent 3 years of follow-up. There were no differences for change in LDL cholesterol or triglycerides. Potential mechanisms for a detrimental effect of pregnancy on HDL cholesterol include hormonal, body composition, or life-style/behavioral changes.

Adolescent↗
PubMed1996

Risk factors for cardiovascular disease in individuals with diabetes. The Strong Heart Study.

Coronary heart disease (CHD) is the leading cause of death among individuals with diabetes. However, information on CHD and its association with known risk factors in populations with high rates of diabetes 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 who have a high prevalence of diabetes. The study group consisted of 4549 adults between 45 and 74 years of age in 13 Indian communities in Arizona, Oklahoma, and South and North Dakota. Rates of diabetes ranged from 33% to 72% in men and women in the three centers. The 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 higher 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 (PR = 3.8 vs 1.9) and CHD (PR = 4.6 vs 1.8) in women than in men. Logistic regression analysis indicated that prevalent CHD was significantly related to age, diabetes, hypertension, albuminuria, percent body fat, smoking, high concentrations of plasma insulin, and low concentrations of high-density lipoprotein (HDL)-cholesterol. These findings from the baseline Strong Heart Study examination emphasize the relative importance of diabetes-associated variables as risk factors for CHD among populations with high rates of diabetes.

Adult↗
PubMed1996

Role of lipids in development of noninsulin-dependent diabetes mellitus: lessons learned from Pima Indians.

We studied the role of lipids in the pathogenesis of noninsulin-dependent diabetes mellitus (NIDDM) in Pima Indians. High plasma levels of nonesterified fatty acid (NEFA) predicted development of NIDDM, but this effect cannot entirely be explained by the glucose-fatty acid cycle. Dyslipidemia, although often associated with diabetes, did not seem to predict NIDDM and might rather be associated with, or the consequence of insulin resistance. In some individuals, a single amino acid substitution in the intestinal fatty acid binding protein could result in increased rates of intestinal absorption of dietary NEFA and thereby contribute to increased lipid-oxidation rates and insulin resistance.

Arizona↗
PubMed1996

Fatty acid modification of membrane fluidity in Chinese hamster ovary (TR715-19) cells.

Dietary saturated fatty acids, especially lauric (12:0), myristic (14:0) and palmitic (16:0) acids, which are hypercholesterolemic, influence cell membrane fatty acid composition and affect LDL receptor function. When membrane phospholipid fatty acids in Chinese hamster ovary cells, containing the human LDL receptor, were modified (Hannah J. S. et al., 1995 Metabolism 44, 1428-1434), LDL receptor function was affected, but correlations with DPH-determined membrane fluidity were weak. The role of fluidity in various membrane domains with respect to the LDL receptor is examined here. Membrane fluidity was assessed by measuring steady-state fluorescence polarization of diphenylhexatriene (DPH) and its polar propionic acid (DPH-PA) and trimethylammonium (TMA-DPH) derivatives from 38 to 4 degrees C in fatty acid modified Chinese hamster ovary cells. Fatty acid changes modulated mid-bilayer fluidity as determined with DPH, but fluidity in phospholipid headgroup domains, assessed with DPH-PA and TMA-DPH, was independent of fatty acyl composition. The DPH fluidity was related to membrane unsaturation (P < 0.02), oleate contents (P < 0.009) in particular, but inversely related (P < 0.0002) to the longer chain (> or = 20 C atoms) unsaturated fatty acids with from four to six double bonds. The LDL binding was independent of fluidity, but there were weak relations between LDL internalization and DPH-PA anisotropy and between LDL degradation and TMA-DPH anisotropy. It was concluded that LDL binding was not related to mid-bilayer fluidity, but the results with the polar probes suggest a role of fluidity in modulating vertical displacement of the LDL/LDL receptor complex across the plasma membrane.

Animals↗
PubMed1996

Regional differences in albuminuria among American Indians: an epidemic of renal disease.

Albuminuria is a risk factor for renal and cardiovascular disease. We conducted a cross sectional survey of 4549 older American Indians in Arizona, Oklahoma and North and South Dakota of (micro)albuminuria. A range of 20.1 to 48.3% of all participants had either micro- (> or = 30 to < 300 mg albumin/g creatinine) or macroalbuminuria (> or = 300 mg albumin/g creatinine). A total of 53% of the participants were diabetic, and the prevalence in Arizona (65 to 70%) was significantly greater than the other two sites. Prevalence of micro- and macroalbuminuria were significantly higher among those who were older, diabetic or hypertensive, and participants from Arizona. Even normotensive, nondiabetic Arizona Indians had higher prevalence rates than similar participants elsewhere. Higher prevalence rates of micro- and macroalbuminuria were also found among Arizona participants than participants with similar degrees of glucose intolerance from the other two sites. Indians reporting the greatest degree of Indian blood were more likely to have abnormal albuminuria (P < 0.0001). The duration of diabetes, fasting plasma glucose, systolic blood pressure, fibrinogen and Indian heritage were independently associated with micro- or macroalbuminuria. The association of albuminuria with subsequent ESRD, cardiovascular morbidity and overall mortality suggests that these American Indians will face a large disease burden. The correlation with reported Indian blood implies a strong component of genetic susceptibility, possibly independent of diabetes.

Aged↗
PubMed1996

Dietary fish oil decreases low-density-lipoprotein clearance in nonhuman primates.

To assess whether fish oil-induced alterations in low-density-lipoprotein (LDL) composition have distinct and important effects on LDL metabolism, we evaluated LDL kinetic behavior in cynomolgus macaques fed an atherogenic diet supplemented with either fish oil (1.6 g n-3 fatty acids; n = 10) or olive oil (n = 9) for > or = 6 mo. LDL from monkeys supplemented with fish oil or olive oil was isolated, labeled with either 125I or 131I, and simultaneously reinjected so that each monkey received its own (autologous injection) and donor (homologous injection) LDL. For LDL injected autologously (monkeys that received their own LDL), the LDL fractional clearance rate (FCR) was reduced in fish oil-supplemented monkeys compared with the olive oil-supplemented controls (0.42 +/- 0.03 compared with 0.56 +/- 0.05 pools/d, P = 0.04). The cholesteryl ester content of fish oil LDL increased compared with olive oil LDL (43 +/- 2% and 36 +/- 3%, respectively, P = 0.03), and the LDL cholesteryl ester content was strongly correlated with autologous LDL clearance (r = -0.76, P = 0.0001). Compared with olive oil LDL, fish oil LDL had a reduced dissociation constant (KD) for binding to the LDL receptor in vitro (KD for fish oil LDL compared with olive oil LDL: 13.9 +/- 1.8 and 7.4 +/- 1.0 mg LDL protein/L, P = 0.03). When both fish oil LDL and olive oil LDL were simultaneously injected into fish oil-supplemented monkeys, the FCR of fish oil LDL was decreased compared with olive oil LDL (0.42 +/- 0.03 and 0.52 +/- 0.04 pools/d, P = 0.006). These data suggest that dietary supplementation with fish oil decreases LDL clearance, and that this effect is mediated, at least in part, by altering LDL structure and reducing the affinity of LDL for its receptor.

Animals↗
PubMed1996

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.

Adult↗
PubMed1996

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.

Aged↗
PubMed1996

Apolipoprotein E polymorphism and LDL size in a biethnic population.

Polymorphisms in the apolipoprotein E (apoE) phenotype (especially E4) are associated with increased cardiovascular risk and particularly with increased concentrations of LDL cholesterol. Little is known, however, about whether alterations in LDL size are associated with the apoE4 phenotype. LDL size was determined by gradient gel electrophoresis, and apoE phenotype was determined by isoelectric focus in 337 nondiabetic subjects from the San Antonio Heart Study, a population-based study of diabetes and cardiovascular risk factors in Mexican Americans and non-Hispanic whites. ApoE4 was associated not only with increases in LDL cholesterol concentrations but also with decreased LDL size. After adjustment for age, sex, body mass index, waist-to-hip ratio, triglyceride, HDL cholesterol, fasting insulin, and diabetic status, the apoE phenotype remained significantly related to LDL size (A) in both men (apoE23, 260.0; apoE33; 256.3; and apoE34, 252.6; P = .01) and women (apoE23, 261.7; apoE33, 257.9; and apoE34, 256.7, P = .045). Variations in apoE phenotype are associated not only with changes in the absolute concentration of LDL cholesterol but also with changes in its composition. These changes are only partly explained by associations of apoE with insulin, triglyceride, and HDL cholesterol.

Adult↗
PubMed1996

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.

Aged↗
PubMed1996

Does free fatty acid infusion impair insulin action also through an increase in oxidative stress?

In vitro studies have demonstrated that free fatty acids (FFA) may enhance oxidative stress. In contrast, no in vivo studies have addressed such a relationship. This four-part study aims at investigating the association between FFA and oxidative stress in healthy volunteers. The following experimental procedures were carried out: 1) determination and simple correlations among fasting plasma FFA, glucose, insulin, plasma thiobarbituric acid-reactive substance (TBARS), the ratio of reduced glutathione (GSH) to oxidized GSH, and lipid hydroperoxide (n = 30); 2) time-dependent effect of FFA on plasma TBARS concentrations and GSH/oxidized GSH ratio (n = 10); 3) dose-dependent effect of FFA on plasma TBARS concentrations (n = 9); and 4) relationship among plasma FFA concentrations, plasma TBARS concentrations, and insulin action (n = 11). The results demonstrate that fasting plasma FFA concentrations correlated with fasting plasma TBARS concentrations (r = 0.65; P < 0.001) and lipid hydroperoxide (r = 0.79; P < 0.001). The correlation between plasma FFA and TBARS remained significant even after adjustment for age, sex, body mass index, and fasting and 2-h plasma glucose concentrations (r = 0.43; P < 0.01). In the time-dependent study, plasma TBARS concentrations increased with the rise in plasma FFA concentrations. In the dose-response study, a progressive increase in fasting plasma FFA concentrations was achieved by varying the Intralipid infusion rate, which also caused plasma TBARS concentrations to increase progressively until they reached a plateau between the last two infusion rates (0.3 and 0.4 mL/min). A euglycemic hyperinsulinemic glucose clamp (insulin infusion rate, 10.2 pmol/kg min for 360 min) was also performed. Simultaneous 10% Intralipid (0.4 mL/min) infusion significantly enhanced plasma TBARS concentrations and inhibited insulin-stimulated whole body glucose disposal (WBGD). GSH infusion (15 mg/min for 360 min) had opposite effects on plasma TBARS concentrations and WBGD. A combined infusion of 10% Intralipid and GSH was associated with a stimulation of WBGD with a magnitude midway between that of 10% Intralipid and GSH infused separately. In conclusion, fasting plasma FFA seems to enhances oxidative stress, which might contribute to the disruptive effects of plasma FFA on insulin-mediated glucose uptake.

Adult↗
PubMed1996

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.

Adult↗
PubMed1996

Binding affinity and particle size of LDL in subjects with moderate hypercholesterolemia: relationship with in vivo LDL metabolism.

The aim of this study was to examine relationships between low density lipoprotein (LDL) metabolism, in vitro binding, and particle size. Twenty four study subjects, 17 men and 7 women, had elevated plasma total cholesterol (TC), ranging from 174 to 232 mg/dl, and LDL cholesterol (LDLC) ranging from 113 to 195 mg/dl after 12 weeks on a Step I diet. The fractional clearance rate (FCR) for LDL ranged from 0.233 to 0.619 pools/day (0.366 +/- 0.021) and was significantly correlated with plasma triglycerides (TG) (P < 0.05). Although there was no relation between FCR and binding in the study group as a whole, those subjects with an FCR within the normal range (< 0.45, n = 20), showed a significant negative correlation between FCR and the KD for LDL binding, (r = 0.52). A subset of four subjects with an elevated FCR (> 0.45) had higher production rate (PR) (P < 0.005) and a significant positive correlation between the KD for LDL binding and FCR (P < 0.05). LDL size varied from 240.0 to 265.8 A and was significantly inversely correlated with plasma TG (P < 0.001) but there was no relation between LDL size and metabolism or binding affinity. Thus, there appears to be a correlation between binding affinity and clearance for subjects who had normal LDL production and clearance rates. On the other hand, mechanisms other than binding affinity appear to influence clearance in subjects with elevated rates of production and clearance.

Adult↗
PubMed1996

Blood pressure in 13 American Indian communities: the Strong Heart Study.

Using National Heart, Lung, and Blood Institute (NHLBI) protocols, researchers measured blood pressure in 4549 American Indians ages 45 to 74 from 13 communities. The prevalence of hypertension ranged from 27% to 56%. More than 70% were aware of the diagnosis, more than 50% were receiving treatment, and 30% controlled their hypertension with medication. Blood pressure was significantly related to glucose intolerance, age, obesity, and alcohol consumption. There was little relation between blood pressure and plasma insulin.

Alcohol Drinking↗
PubMed1995

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.

Aged↗