Associations of diet soda and non-caloric artificial sweetener use with markers of glucose and insulin homeostasis and incident diabetes: the Strong Heart Family Study.

BACKGROUND/OBJECTIVES: Non-caloric artificial sweeteners (NAS) are marketed as healthier alternatives to sugar, but the relationship between consumption of NAS and development of diabetes is unclear. This study assessed the associations of diet soda and NAS consumption with (1) early markers of insulin and glucose homeostasis (cross-sectionally) and (2) incident diabetes (over an average of 8 years of follow-up) among American Indians, a population with high rates of obesity. SUBJECTS/METHODS: The study population included Strong Heart Family Study participants without cardiovascular disease or diabetes who participated in the 2007-2009 study exam (n = 1359). Diet soda and NAS consumption were assessed using a Block food frequency questionnaire and supplemental NAS questionnaire at the study exam. Fasting plasma glucose and insulin were measured during the study exam after a 12-h overnight fast. Participants were followed for incident diabetes through December 2017 using a single phone interview and medical record review; diabetes was identified by self-report and confirmed by documentation in medical records. Associations of diet soda and NAS consumption with fasting insulin, glucose, and incident diabetes were assessed using generalized estimating equations (fasting insulin and glucose analyses) and parametric survival models with Weibull distributions (incident diabetes analyses). RESULTS: Just under half of participants reported regularly consuming diet soda (40%) or using NAS to sweeten their beverages (41%). During an average 8 years of follow-up, we identified 98 cases of incident diabetes. After correction for multiple comparisons, there were no statistically significant associations of reported diet soda and NAS consumption with fasting insulin, fasting glucose, or incident diabetes. CONCLUSIONS: Although reported consumption of diet soda and NAS were high, neither were associated with diabetes risk.

Risk Factors and Prediction of Stroke in a Population with High Prevalence of Diabetes: The Strong Heart Study.

BACKGROUND AND OBJECTIVE: American Indians have a high prevalence of diabetes and higher incidence of stroke than that of whites and blacks in the U.S. Stroke risk prediction models based on data from American Indians would be of clinical and public health value. METHODS AND RESULTS: A total of 3483 (2043 women) Strong Heart Study participants free of stroke at baseline were followed from 1989 to 2010 for incident stroke. Overall, 297 stroke cases (179 women) were identified. Cox models with stroke-free time and risk factors recorded at baseline were used to develop stroke risk prediction models. Assessment of the developed stroke risk prediction models regarding discrimination and calibration was performed by an analogous C-statistic (C) and a version of the Hosmer-Lemeshow statistic (HL), respectively, and validated internally through use of Bootstrapping methods. RESULTS: Age, smoking status, alcohol consumption, waist circumference, hypertension status, an-tihypertensive therapy, fasting plasma glucose, diabetes medications, high/low density lipoproteins, urinary albumin/creatinine ratio, history of coronary heart disease/heart failure, atrial fibrillation, or Left ventricular hypertrophy, and parental history of stroke were identified as the significant optimal risk factors for incident stroke. DISCUSSION: The models produced a C = 0.761 and HL = 4.668 (p = 0.792) for women, and a C = 0.765 and HL = 9.171 (p = 0.328) for men, showing good discrimination and calibration. CONCLUSIONS: Our stroke risk prediction models provide a mechanism for stroke risk assessment designed for American Indians. The models may be also useful to other populations with high prevalence of obesity and/or diabetes for screening individuals for risk of incident stroke and designing prevention programs.

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

PURPOSE: The metabolic abnormalities that accompany diabetes mellitus are associated with an increased risk of many cancers. These associations, however, have not been well studied in American Indian populations, which experience a high prevalence of diabetes. The Strong Heart Study is a population-based, prospective cohort study with extensive characterization of diabetes status. METHODS: Among a total cohort of 4,419 participants who were followed for up to 20 years, 430 cancer deaths were identified. RESULTS: After adjusting for sex, age, education, smoking status, drinking status, and body mass index, participants with diabetes at baseline showed an increased risk of gastric (HR 4.09; 95% CI 1.42-11.79), hepatocellular (HR 2.94; 95% CI 1.17-7.40), and prostate cancer mortality (HR 3.10; 95% CI 1.22-7.94). Further adjustment for arsenic exposure showed a significantly increased risk of all-cause cancer mortality with diabetes (HR 1.27; 95% CI 1.03-1.58). Insulin resistance among participants without diabetes at baseline was associated with hepatocellular cancer mortality (HR 4.70; 95% CI 1.55-14.26). CONCLUSIONS: Diabetes mellitus, and/or insulin resistance among those without diabetes, is a risk factor for gastric, hepatocellular, and prostate cancer in these American Indian communities, although relatively small sample size suggests cautious interpretation. Additional research is needed to evaluate the role of diabetes and obesity on cancer incidence in American Indian communities as well as the importance of diabetes prevention and control in reducing the burden of cancer incidence and mortality in the study population.

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

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

Cadmium exposure and cancer mortality in a prospective cohort: the strong heart study.

BACKGROUND: Cadmium (Cd) is a toxic metal classified as a human carcinogen by the International Agency for Research on Cancer. OBJECTIVE: We evaluated the association of long-term Cd exposure, as measured in urine, with cancer mortality in American Indians from Arizona, Oklahoma, and North and South Dakota who participated in the Strong Heart Study during 1989-1991. METHODS: The Strong Heart Study was a prospective cohort study of 3,792 men and women 45-74 years of age who were followed for up to 20 years. Baseline urinary Cd (U-Cd) was measured using inductively coupled plasma mass spectrometry. We assessed cancer events by annual mortality surveillance. RESULTS: The median (interquintile range) U-Cd concentration was 0.93 (0.55, 1.63) µg/g creatinine. After adjusting for sex, age, smoking status, cigarette pack-years, and body mass index, the adjusted hazard ratios (HRs) comparing the 80th versus the 20th percentiles of U-Cd were 1.30 (95% CI: 1.09, 1.55) for total cancer, 2.27 (95% CI: 1.58, 3.27) for lung cancer, and 2.40 (95% CI: 1.39, 4.17) for pancreatic cancer mortality. For all smoking-related cancers combined, the corresponding HR was 1.56 (95% CI: 1.24, 1.96). Cd was not significantly associated with liver, esophagus and stomach, colon and rectum, breast, prostate, kidney, or lymphatic and hematopoietic cancer mortality. On the basis of mediation analysis, we estimated that the percentage of lung cancer deaths due to tobacco smoking that could be attributed to Cd exposure was 9.0% (95% CI: 2.8, 21.8). CONCLUSIONS: Low-to-moderate Cd exposure was prospectively associated with total cancer mortality and with mortality from cancers of the lung and pancreas. The implementation of population-based preventive measures to decrease Cd exposure could contribute to reducing the burden of cancer.

Insulin resistance, incident cardiovascular diseases, and decreased kidney function among nondiabetic American Indians: the Strong Heart Study.

OBJECTIVE: Prevalence of insulin resistance is high in the American Indian population, likely as a result of the high prevalence of obesity. This condition may be influential for clinical outcomes such as cardiovascular disease (CVD) and decreased kidney function. RESEARCH DESIGN AND METHODS: Normal glucose tolerant (NGT) participants free of hypertension and CVD at the baseline examination (1989-1992) (N=964) of the Strong Heart Study were selected to explore the cross-sectional association between insulin resistance quantified by homeostasis model assessment (HOMA-IR) and demographic, behavioral, and cardiometabolic variables. The longitudinal association between baseline HOMA-IR and the development of CVD was also explored. The longitudinal association between baseline HOMA-IR and the development of high urinary albumin-to-creatinine ratio was explored among nondiabetic participants (N=1,401). RESULTS: Cross-sectionally, HOMA-IR was associated with sex, residence location, smoking, and high-risk cardiometabolic profile. Prospectively, insulin resistance is associated with the development of CVD and decreased kidney function in this population. CONCLUSIONS: Insulin resistance may have an important role in the pathogenesis of CVD and chronic kidney disease. Since obesity contributes to the development of insulin resistance, intervention focusing on modifiable factors such as physical activity and weight control may reduce the development of these diseases.

Dietary Intake among American Indians with Metabolic Syndrome - Comparison to Dietary Recommendations: the Balance Study.

BACKGROUND: American Indians have a very high prevalence of metabolic syndrome that increases their risk of developing cardiovascular disease and type 2 diabetes. Dietary habits are of central importance in the prevention and treatment of metabolic syndrome. OBJECTIVE: The main objective of this article was to describe dietary intake among American Indians with metabolic syndrome and compare it to several dietary recommendations. A secondary objective was to identify certain barriers to dietary adherence experienced by this population. METHODS: A total of 213 participants with metabolic syndrome were enrolled in the Balance Study, a randomized controlled trial with two intervention groups: Guided Group and Self-Managed Group. Dietary intake was assessed using the Block Food Frequency questionnaire. Dietary intakes were evaluated against the Dietary Guidelines for Americans. RESULTS: Intakes of saturated fats, cholesterol, and sodium were higher and intakes of dietary fiber, calcium, magnesium, potassium, vitamin A, vitamin D, and vitamin E were lower than recommended. Additionally, intake of many food groups was noticeably low. Economic factors seem to be related to low adherence to dietary recommendations. CONCLUSION: Results showed low adherence by the participants to dietary recommendations for key nutrients and food groups related to risk factors for metabolic syndrome, type 2 diabetes, and cardiovascular disease. Economic factors are related to this low adherence. These findings illustrate a need to develop innovative, focused, and perhaps individualized health promotion strategies that can improve dietary habits of American Indians with metabolic syndrome.

A cardiovascular risk reduction program for American Indians with metabolic syndrome: the Balance Study.

The Balance Study is a randomized controlled trial designed to reduce cardiovascular disease (CVD) risk in 200 American Indian (AI) participants with metabolic syndrome who reside in southwestern Oklahoma. Major risk factors targeted include weight, diet, and physical activity. Participants are assigned randomly to one of two groups, a guided or a self-managed group. The guided group attends intervention meetings that comprise education and experience with the following components: diet, exercise, AI culture, and attention to emotional wellbeing. The self-managed group receives printed CVD prevention materials that are generally available. The duration of the intervention is 24 months. Several outcome variables will be compared between the two groups to assess the effectiveness of the intervention program.

Markers of inflammation, metabolic risk factors, and incident heart failure in American Indians: the Strong Heart Study.

Inflammation may play a role in increased risk of heart failure (HF) that is associated with obesity, metabolic syndrome (MS), and diabetes. This study investigated associations between inflammatory markers, MS, and incident HF in a population with a high prevalence of diabetes, obesity, and MS. The cohort consisted of 3098 American Indians without prevalent cardiovascular disease who had C-reactive protein (CRP) and fibrinogen measured at the Strong Heart Study phase II examination. Independent associations between inflammatory markers, MS, and HF were analyzed by Cox hazard models. During a mean follow-up of 11 years, 218 participants developed HF. After the adjustment for cardiovascular risk factors, fibrinogen, (hazard ratio [HR], 1.36; 95% confidence interval [CI], 1.15-1.59) but not CRP (HR, 1.25; 95% CI, 0.97-1.32) remained a significant HF predictor. In individuals without diabetes, concomitant presence of MS and elevated CRP or fibrinogen increased HF risk (for MS and CRP: HR, 2.02; 95% CI, 0.95-4.31; for CRP and fibrinogen: HR, 1.75; 95% CI, 0.83-3.72). In a population with a high prevalence of obesity, MS, and diabetes, elevated CRP and fibrinogen increased HF risk. These associations are attenuated by the adjustments for conventional risk factors suggesting that inflammation acts in concert with metabolic and clinical risk factors in increasing HF risk.

Acute myocardial infarction quality of care: the Strong Heart Study.

OBJECTIVES: Evaluate the quality of care provided patients with acute myocardial infarction and compare with similar national and regional data. DESIGN: Case series. SETTING: The Strong Heart Study has extensive population-based data related to cardiovascular events among American Indians living in three rural regions of the United States. PARTICIPANTS: Acute myocardial infarction cases (72) occurring between 1/1/2001 and 12/31/2006 were identified from a cohort of 4549 participants. OUTCOME MEASURES: The proportion of cases that were provided standard quality of care therapy, as defined by the Healthcare Financing Administration and other national organizations. RESULTS: The provision of quality services, such as administration of aspirin on admission and at discharge, reperfusion therapy within 24 hours, prescription of beta blocker medication at discharge, and smoking cessation counseling were found to be 94%, 91%, 92%, 86% and 71%, respectively. The unadjusted, 30 day mortality rate was 17%. CONCLUSION: Despite considerable challenges posed by geographic isolation and small facilities, process measures of the quality of acute myocardial infarction care for participants in this American Indian cohort were comparable to that reported for Medicare beneficiaries nationally and within the resident states of this cohort.

Prevalence and risks factors of age-related macular degeneration in Oklahoma Indians: the Vision Keepers Study.

OBJECTIVE: To determine the prevalence of age-related macular degeneration (AMD) and to identify its risk factors in an Oklahoma Indian population. DESIGN: Cross-sectional study design. PARTICIPANTS: Included 1019 Oklahoma Indians who participated in baseline and second examinations of the Strong Heart Study. METHODS: Retinal photographs of at least 1 eye were obtained and graded for AMD by the University of Wisconsin Ocular Epidemiology Reading Center. Retinal photographs of 986 participants were considered gradable and were included in the study. MAIN OUTCOME MEASURES: Age-related macular degeneration (early and late). RESULTS: The overall prevalence of AMD in the study was 35.2%, including a prevalence of 0.81% for late AMD. The prevalence of early AMD increased from 30.6% in those aged 48 to 59 years to 46.1% in those 70 to 82 years of age. When potential risk factors were analyzed individually (univariate analyses), men with hypertension had a significantly higher prevalence of AMD (P = 0.02) than those without hypertension. In women, high-density lipoprotein cholesterol and sun exposure were associated positively with the prevalence of AMD (P = 0.01), whereas a history of using multivitamins was associated with lower AMD prevalence (P = 0.005). When multiple risk factors were analyzed simultaneously using logistic regression, only age showed significant association with AMD in both men (P = 0.02) and women (P<0.0001) and was the only significant risk factor in men. In women, multivitamin use and total cholesterol had a significant inverse association with AMD, whereas sun exposure and high-density lipoprotein cholesterol had a positive association. When men and women were combined, age and high-density lipoprotein cholesterol had significant positive associations, whereas total cholesterol, multivitamin use, and current alcohol use showed a significant inverse association with AMD. CONCLUSIONS: This study was the first to report a detailed prevalence of AMD in Oklahoma Indians and its risk factors. The prevalence seemed to be relatively high compared with that in other ethnic groups. Some of the modifiable risk factors identified confirmed previous findings and can be used to design preventive programs to reduce the burden of AMD, although longitudinal data are still needed.

Physical activity levels in American-Indian adults: the Strong Heart Family Study.

BACKGROUND: A limited body of evidence, mostly based on self-report, is available regarding physical activity levels among American-Indian adults. PURPOSE: This study aims to examine physical activity levels objectively using pedometers among a large cohort of American-Indian adult participants in the Strong Heart Family Study (SHFS). METHODS: Physical activity levels in 2604 American-Indian adults, aged 18-91 years, from 13 American-Indian communities were assessed using Accusplit AE120 pedometers over a period of 7 days during 2001-2003. Anthropometric measurements were also assessed. All data analyses were conducted in 2008. Age-adjusted Pearson correlations were used to examine the relationship between average steps per day and age and anthropometric variables. Subjects were placed in age and BMI categories (according to National Heart, Lung, and Blood Institute cut points) to examine trends in physical activity with increasing age and BMI. RESULTS: Daily pedometer steps ranged from 1001 to 38,755. Mean step counts by age group for men were 5384 (aged 18-29 years); 5120 (aged 30-39 years); 5040 (aged 40-49 years); 4561(aged 50-59 years); 4321 (aged 60-69 years); and 3768 (aged >or=70 years) and for women, 5038 (aged 18-29 years); 5112 (aged 30-39 years); 5054 (aged 40-49 years); 4582 (aged 50-59 years); 3653 (aged 60-69 years); and 3770 (aged >or=70 years). A significant linear trend in physical activity was noted with increasing age (p=0.002 for men, p<0.0001 for women) and with increasing BMI (p=0.05 for men, p=0.04 for women). CONCLUSIONS: Objectively measured data suggest that inactivity is a problem among American-Indian adults and that a majority of American-Indian adults in the SHFS may not be meeting the minimum physical activity public health recommendations. Efforts to increase physical activity levels in this population are warranted.

Incidence and risk factors for stroke in American Indians: the Strong Heart Study.

BACKGROUND: There are few published data on the incidence of fatal and nonfatal stroke in American Indians. The aims of this observational study were to determine the incidence of stroke and to elucidate stroke risk factors among American Indians. METHODS AND RESULTS: This report is based on 4549 participants aged 45 to 74 years at enrollment in the Strong Heart Study, the largest longitudinal, population-based study of cardiovascular disease and its risk factors in a diverse group of American Indians. At baseline examination in 1989 to 1992, 42 participants (age- and sex-adjusted prevalence proportion 1132/100 000, adjusted to the age and sex distribution of the US adult population in 1990) had prevalent stroke. Through December 2004, 306 (6.8%) of 4507 participants without prior stroke suffered a first stroke at a mean age of 66.5 years. The age- and sex-adjusted incidence was 679/100 000 person-years. Nonhemorrhagic cerebral infarction occurred in 86% of participants with incident strokes; 14% had hemorrhagic stroke. The overall age-adjusted 30-day case-fatality rate from first stroke was 18%, with a 1-year case-fatality rate of 32%. Age, diastolic blood pressure, fasting glucose, hemoglobin A(1c,) smoking, albuminuria, hypertension, prehypertension, and diabetes mellitus were risk factors for incident stroke. CONCLUSIONS: Compared with US white and black populations, American Indians have a higher incidence of stroke. The case-fatality rate for first stroke is also higher in American Indians than in the US white or black population in the same age range. Our findings suggest that blood pressure and glucose control and smoking avoidance may be important avenues for stroke prevention in this population.

Subjective and objective sleep quality and aging in the sleep heart health study.

OBJECTIVES: To examine the extent to which subjective and objective sleep quality are related to age independent of chronic health conditions. DESIGN: Cross-sectional study. SETTING: The Sleep Heart Health Study (SHHS) is a multicenter study designed to determine the cardiovascular consequences and the natural history of sleep disordered breathing. PARTICIPANTS: Five thousand four hundred seven community-dwelling adults who participated in the SHHS (mean age 63, range 45-99; 52% women). MEASUREMENTS: Unattended home polysomnography (PSG) and sleep questionnaires. RESULTS: Older age was associated with shorter sleep time, diminished sleep efficiency, and more arousals in men and women. In men, age was independently associated with more Stage 1 and Stage 2 sleep and less slow-wave (Stage 3 to 4) and rapid eye movement sleep. In women, older age was less strongly associated according to linear trend with sleep stage. Conversely, poor subjective sleep quality was not associated with older age in men, but older women had more trouble falling asleep, and there was a trend toward older women having more problems with waking up during the night and waking up too early. Associations between self-report and directly measured sleep time and sleep latency were low to moderate across age groups (correlation coefficient=0.06-0.32). CONCLUSION: Older age was more strongly associated with poorer sleep according to PSG in men than women, yet the subjective report of poor sleep with older age was stronger in women. The higher prevalence of chronic health conditions, including sleep apnea, in older adults did not explain changes of sleep parameters with aging and age-sex differences in these relationships.

A longitudinal study of risk factors for incident albuminuria in diabetic American Indians: the Strong Heart Study.

BACKGROUND: There have been no studies that use longitudinal data with more than 2 measurements and methods of longitudinal data analysis to identify risk factors for incident albuminuria over time more effectively. STUDY DESIGN: Longitudinal study. SETTINGS & PARTICIPANTS: A subgroup of participants in the Strong Heart Study, a population-based sample of American Indians, in central Arizona, Oklahoma, and North and South Dakota. Participants with diabetes without albuminuria were followed up for a mean of 4 years. PREDICTORS: Age, sex, study center, high-density lipoprotein and low-density lipoprotein cholesterol levels, triglyceride level, body mass index, systolic blood pressure, use of antihypertensive medication, smoking, hemoglobin A(1c) level, fasting glucose level, type of diabetes therapy, diabetes duration, plasma creatinine level, and urinary albumin-creatinine ratio (UACR). OUTCOMES & MEASUREMENTS: Albuminuria was defined as UACR of 30 mg/g or greater. Urine creatinine and albumin were measured by using the picric acid method and a sensitive nephelometric technique, respectively. RESULTS: Of 750 and 568 participants with diabetes without albuminuria and with normal plasma creatinine levels at the first and second examinations, 246 and 132 developed albuminuria by the second and third examinations, respectively. Incident albuminuria was predicted by baseline UACR, fasting glucose level, systolic blood pressure, plasma creatinine level, study center, current smoking, and use of angiotensin-converting enzyme inhibitors and antidiabetic medications. UACR of 10 to 30 mg/g increased the odds of developing albuminuria 2.7-fold compared with UACR less than 5 mg/g. LIMITATIONS: Single random morning urine specimen. CONCLUSIONS: Many risk factors identified for incident albuminuria can be modified. Control of blood pressure and glucose level, smoking cessation, and use of angiotensin-converting enzyme inhibitors may reduce the incidence of albuminuria.

Albuminuria within the "normal" range and risk of cardiovascular disease and death in American Indians: the Strong Heart Study.

BACKGROUND: "Normal" albuminuria has been defined as urinary albumin-creatinine ratio (UACR) less than 30 mg/g (3.4 mg/mmol). Whether higher UACR within this range independently predicts cardiovascular disease (CVD) and CVD death is uncertain. METHODS: A total of 3,000 participants aged 45 to 74 years with a UACR less than 30 mg/g and free of CVD at the baseline examination of the Strong Heart Study (SHS) were evaluated. Survival time was calculated from the baseline examination to the first nonfatal CVD, fatal CVD, or December 31, 2002. RESULTS: During follow-up (average, 10.4 years), 383 incident nonfatal CVD and 145 fatal CVD cases were ascertained. After adjustment for conventional CVD risk factors, participants with a UACR in the third (UACR >or= 5.4 to <10.2 mg/g [>or=0.6 to <1.1 mg/mmol] in men, >or=7.6 to <12.9 mg/g [>or=0.9 to <1.4 mg/mmol] in women) and the fourth (UACR >or=10.2 to <30 mg/g in men, >or=12.9 to <30 mg/g in women) quartiles had 41% and 72% greater risks of all CVD events and 118% and 199% greater risks of CVD mortality than those in the lowest quartile (UACR < 2.7 mg/g [<0.3 mg/mmol] in men, <4.3 mg/g [<0.5 mg/mmol] in women), respectively. In subgroup analysis, these associations were more pronounced in persons with diabetes. CONCLUSION: In the SHS cohort of middle-aged to elderly American Indians, albuminuria levels less than the traditional cutoff value predict CVD. Our findings agree with a growing number of studies questioning the concept that UACR less than 30 mg/g is normal.

Prediction of coronary heart disease in a population with high prevalence of diabetes and albuminuria: the Strong Heart Study.

BACKGROUND: The present article presents equations for the prediction of coronary heart disease (CHD) in a population with high rates of diabetes and albuminuria, derived from data collected in the Strong Heart Study, a longitudinal study of cardiovascular disease in 13 American Indian tribes and communities in Arizona, North and South Dakota, and Oklahoma. METHODS AND RESULTS: Participants of the Strong Heart Study were examined initially in 1989-1991 and were monitored with additional examinations and mortality and morbidity surveillance. CHD outcome data through December 2001 showed that age, gender, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein cholesterol, smoking, diabetes, hypertension, and albuminuria were significant CHD risk factors. Hazard ratios for ages 65 to 75 years, hypertension, LDL cholesterol > or = 160 mg/dL, diabetes, and macroalbuminuria were 2.58, 2.01, 2.44, 1.66, and 2.11 in men and 2.03, 1.69, 2.17, 2.26, and 2.69 in women, compared with ages 45 to 54 years, normal blood pressure, LDL cholesterol <100 mg/dL, no diabetes, and no albuminuria. Prediction equations for CHD and a risk calculator were derived by gender with the use of Cox proportional hazards model and the significant risk factors. The equations provided good discrimination ability, as indicated by a c statistic of 0.70 for men and 0.73 for women. Results from bootstrapping methods indicated good internal validation and calibration. CONCLUSIONS: A "risk calculator" has been developed and placed on the Strong Heart Study Web site, which provides predicted risk of CHD in 10 years with input of these risk factors. This may be valuable for diverse populations with high rates of diabetes and albuminuria.

Prehypertension, diabetes, and cardiovascular disease risk in a population-based sample: the Strong Heart Study.

There are few data about the impact of the recently-defined category of prehypertension (systolic blood pressure 120 to 139 mm Hg or diastolic blood pressure 80 to 89 mm Hg) on cardiovascular disease incidence. It is also unknown whether this association differs between individuals with or without diabetes. A total of 2629 Strong Heart Study participants free from hypertension and cardiovascular disease at baseline examination were followed for 12 years to observe incident cardiovascular disease. Approximately 42% of the 2629 participants had diabetes. We assessed the prevalence of prehypertension and the hazard ratios of incident cardiovascular disease associated with prehypertension. Prehypertension was more prevalent in diabetic than nondiabetic participants (59.4% versus 48.2%, P<0.001 adjusted for age). Compared with nondiabetic participants with normal blood pressure, the hazard ratios of cardiovascular disease were 3.70 (95% confidence interval: 2.66, 5.15) for those with both prehypertension and diabetes, 1.80 (1.28, 2.54) for those with prehypertension alone and 2.90 (2.03, 4.16) for those with diabetes alone. Impaired glucose tolerance or impaired fasting glucose also greatly increased the cardiovascular disease risk in prehypertensive people. Clinical investigation of more aggressive interventions, such as drug treatment for blood pressure control for prehypertensive individuals with impaired fasting glucose, impaired glucose tolerance, or diabetes is warranted.

Different factor loadings for SF36: the Strong Heart Study and the National Survey of Functional Health Status.

BACKGROUND: To increase our understanding of the psychometric characteristics and factor structure of the SF36 in older American Indian populations. METHODS: Between 1993 and 1995, SF36 data were collected from 3,488 Phase II participants of the Strong Heart Study (SHS) between the ages of 48 and 81. Comparison data were provided by an age- and gender-matched sample (n = 695) from the National Survey of Functional Health Status (NSFHS) conducted in 1989 and 1990. RESULTS: Generally, the basic psychometric analyses showed that the SF36 performed adequately in these older American Indians. Exploratory factor analyses indicated that a one-factor model best fit the data for both older groups. On the other hand, confirmatory factor analyses showed that a two-factor model with correlated factors provided a superior fit to the data than a one-factor model. An assumption of equivalent factor loadings for the SHS and NSFHS groups was untenable. CONCLUSION: These analyses demonstrate that use of summary scores assuming a differentiated physical/mental functioning structure is likely improper in at least some populations. The SF36 provides an important opportunity to understand cultural differences in the conceptualization and measurement of health-related quality of life.

Cardiovascular disease and risk factors in three Alaskan Eskimo populations: the Alaska-Siberia project.

OBJECTIVES: To determine the prevalence of CVD and to identify and characterize associated risk factors in three distinct Eskimo populations. STUDY DESIGN: Cross-sectional. METHODS: A slightly modified Strong Heart Study protocol was followed to examine 454 participants, aged 25-91, from four villages. RESULTS: Overall, 6% of the participants under 55 years of age and 26% of those > or = 55 years of age showed evidence of CHD by ECG, or in patient records. The prevalence of "definite coronary heart disease" (CHD) in women with glucose intolerance (GI) was 21.0%, compared to 2.4% in those with normal glucose tolerance (NGT). Men had comparable values of 26.7% and 6.3%. In addition, comparable values for "possible CHD" were 29.7% vs 6.0% for women and 21.4% vs 8.0% for men. GI was associated with relatively higher prevalences of CHD in women than in men (prevalence ratio = 8.5 vs 4.3). CHD was significantly related to age, glucose intolerance and insulin. Hypertension and obesity were significantly associated with CHD only in some ethnic groups. The prevalence of current smokers was 56%. CONCLUSIONS: Recent changes in lifestyle and diet of Alaskan Eskimos, leading to obesity, hypertension, insulin resistance and DM, contribute to an increased risk for cardiovascular disease.