Mori Ramulus Suppresses Hydrogen Peroxide-Induced Oxidative Damage in Murine Myoblast C2C12 Cells through Activation of AMPK

Mori Ramulus, the dried twigs of Morus alba L., has been attracting attention for its potent antioxidant activity, but its role in muscle cells has not yet been elucidated. The purpose of this study was to evaluate the protective effect of aqueous extracts of Mori Ramulus (AEMR) against oxidative stress caused by hydrogen peroxide (H₂O₂) in C2C12 mouse myoblasts, and in dexamethasone (DEX)-induced muscle atrophied models. Our results showed that AEMR rescued H₂O₂-induced cell viability loss and the collapse of the mitochondria membrane potential. AEMR was also able to activate AMP-activated protein kinase (AMPK) in H₂O₂-treated C2C12 cells, whereas compound C, a pharmacological inhibitor of AMPK, blocked the protective effects of AEMR. In addition, H₂O₂-triggered DNA damage was markedly attenuated in the presence of AEMR, which was associated with the inhibition of reactive oxygen species (ROS) generation. Further studies showed that AEMR inhibited cytochrome c release from mitochondria into the cytoplasm, and Bcl-2 suppression and Bax activation induced by H₂O₂. Furthermore, AEMR diminished H₂O₂-induced activation of caspase-3, which was associated with the ability of AEMR to block the degradation of poly (ADP-ribose) polymerase, thereby attenuating H₂O₂-induced apoptosis. However, compound C greatly abolished the protective effect of AEMR against H₂O₂-induced C2C12 cell apoptosis, including the restoration of mitochondrial dysfunction. Taken together, these results demonstrate that AEMR could protect C2C12 myoblasts from oxidative damage by maintaining mitochondrial function while eliminating ROS, at least with activation of the AMPK signaling pathway. In addition, oral administration of AEMR alleviated gastrocnemius and soleus muscle loss in DEX-induced muscle atrophied rats. Our findings support that AEMR might be a promising therapeutic candidate for treating oxidative stress-mediated myoblast injury and muscle atrophy.

Serum uric acid does not predict incident metabolic syndrome in a population with high prevalence of obesity

AIM

To evaluate whether uric acid (UA) predicts 4-yr incidence of metabolic syndrome (MetS) in non-diabetic participants of the Strong Heart Study (SHS) cohort.

METHODS AND RESULTS

In this population-based prospective study we analyzed 1499 American Indians (890 women), without diabetes or MetS, controlled during the 4th SHS exam and re-examined 4 years later during the 5th SHS exam. Participants were divided into sex-specific tertiles of UA and the first two tertiles (group N) were compared with the third tertile (group H). Body mass index (BMI = 28.3 ± 7 vs. 31.1 ± 7 kg/m(2)), fat-free mass (FFM = 52.0 ± 14 vs. 54.9 ± 11 kg), waist-to-hip ratio, HOMA-IR (3.66 vs. 4.26), BP and indices of inflammation were significantly higher in group H than in group N (all p < 0.001). Incident MetS at the time of the 5th exam was more frequent in group H than group N (35 vs. 28%, OR 1.44 (95% CI = 1.10-1.91; p < 0.01). This association was still significant (OR = 1.13, p = 0.04) independently of family relatedness, sex, history of hypertension, HOMA-IR, central adiposity and renal function, but disappeared when fat-free mass was included in the model.

CONCLUSIONS

In the SHS, UA levels are associated to parameters of insulin resistance and to indices of inflammation. UA levels, however, do not predict incident MetS independently of the initial obesity-related increased FFM.

Cardiometabolic risk in overweight subjects with or without relative fat-free mass deficiency: the Strong Heart Study

BACKGROUND AND AIM

Sarcopenia is a condition mainly due to loss of fat-free mass (FFM) in elderly individuals. RFFMD, however, is also frequent in obese subjects due to abnormal body composition. Objective of this study was to evaluate the impact of relative fat-free mass deficiency (RFFMD) on cardiometabolic (CM) risk in obese normoglycemic individuals.

METHODS AND RESULTS

Overweight/obese American Indians from the Strong Heart Study population, without diabetes and with FBG ≤ 110 mg/dL and with GFR >60 mg/mL/1.73 m(2) were selected for this analysis (n = 742). RFFMD was defined on the basis of a multivariable equation previously reported. Fasting glucose and 2 h-OGTT were measured together with urine albumin/creatinine excretion, laboratory and anthropometric parameters. In addition to lower FFM and greater adipose mass, participants with RFFMD had higher body mass index, waist circumference, C-reactive protein, fibrinogen, insulin resistance and urinary albumin/creatinine than participants with normal FFM (all p < 0.001); they also had a greater prevalence of hypertension, impaired glucose tolerance (IGT) or OGTT-diabetes than participants with normal FFM (all p < 0.003) and a near 2-fold greater probability of significant proteinuria (p < 0.01). RFFMD was more frequent in women than in men: significant sex-RFFMD interactions were found for BMI and waist circumference (both p < 0.0001).

CONCLUSIONS

RFFMD in overweight/obese normoglycemic individuals is associated with greater probability of hypertension, abnormalities of glucose tolerance and proteinuria. Assessment of RFFRMD might, therefore, help stratifying cardiometabolic risk among normoglycemic individuals with overweight/obesity.

Epidemiology and genetic determinants of progressive deterioration of glycaemia in American Indians: the Strong Heart Family Study

AIMS/HYPOTHESIS

Type 2 diabetes is a chronic, heterogeneous disease and a major risk factor for cardiovascular diseases. The underlying mechanisms leading to progression to type 2 diabetes are not fully understood and genetic tools may help to identify important pathways of glycaemic deterioration.

METHODS

Using prospective data on American Indians from the Strong Heart Family Study, we identified 373 individuals defined as progressors (diabetes incident cases), 566 individuals with transitory impaired fasting glucose (IFG) and 1,011 controls (normal fasting glycaemia at all visits). We estimated the heritability (h(2)) of the traits and the evidence for association with 16 known variants identified in type 2 diabetes genome-wide association studies.

RESULTS

We noted high h(2) for diabetes progression (h(2) = 0.65 ± 0.16, p = 2.7 × 10(-6)) but little contribution of genetic factors to transitory IFG (h(2) = 0.09 ± 0.10, p = 0.19) for models adjusted for multiple risk factors. At least three variants (in WFS1, TSPAN8 and THADA) were nominally associated with diabetes progression in age- and sex-adjusted analyses with estimates showing the same direction of effects as reported in the discovery European ancestry studies.

CONCLUSIONS/INTERPRETATION

Our findings do not exclude these loci for diabetes susceptibility in American Indians and suggest phenotypic heterogeneity of the IFG trait, which may have implications for genetic studies when diagnosis is based on a single time-point measure.

Dietary patterns and their association with cardiovascular risk factors in a population undergoing lifestyle changes: The Strong Heart Study

BACKGROUND AND AIMS

Rates of cardiovascular disease (CVD) are disproportionately high in American Indians (AI), and changes in lifestyle may be responsible. It is not known whether diverse dietary patterns exist in this population and whether the patterns are associated with CVD risk factors. This article describes the relationships between dietary patterns and CVD risk factors in this high-risk population.

METHODS AND RESULTS

Nutrition data were collected via food frequency questionnaire from 3438 Strong Heart Study (SHS) participants, ≥ age 15 y. All participants were members of 94 extended families. The final sample consisted of 3172 men and women. Diet patterns were ascertained using factor analysis with the principal component factoring method. We derived four predominant dietary patterns: Western, traditional AI/Mexican, healthy, and unhealthy. Participants following the Western pattern had higher LDL cholesterol (LDL-C) (p < 0.001), slightly higher systolic blood pressure (BP) (p < 0.001), lower HDL cholesterol (HDL-C) (p < 0.001), and slightly lower homeostasis model assessment estimates of insulin resistance (HOMA-IR) in the lowest vs. highest deciles of adherence to this pattern (p < 0.001). The traditional diet was associated with higher HDL-C (p < 0.001), but higher body mass index (BMI) (p < 0.001) and HOMA-IR (p < 0.001). Followers of the healthy pattern had lower systolic BP, LDL-C, BMI, and HOMA-IR in increasing deciles (p < 0.001). The unhealthy pattern was associated with higher LDL-C.

CONCLUSIONS

Dietary patterns reflect the changing lifestyle of AI and several of the patterns are associated with CVD risk factors. Evolving methods of food preparation have made the traditional pattern less healthy.

Does cardiovascular phenotype explain the association between diabetes and incident heart failure? The Strong Heart Study

BACKGROUND AND AIMS

Diabetes remains a predictor of incident heart failure (HF), independent of intercurrent myocardial infarction (MI) and concomitant risk factors. Initial cardiovascular (CV) characteristics, associated with incident heart failure (HF) might explain the association of diabetes with incident HF.

METHODS AND RESULTS

Participants to the 2nd Strong Heart Study exam, without prevalent HF or coronary heart disease, or glomerular filtration rate <30 mL/min/1.73 m(2), were analyzed (n = 2757, 1777 women, 1278 diabetic). Cox regression of incident HF (follow-up 8.91 ± 2.76 years) included incident MI censored as a competing risk event. Acute MI occurred in 96 diabetic (7%) and 84 non-diabetic participants (6%, p = ns). HF occurred in 156 diabetic (12%) and in 68 non-diabetic participants (5%; OR = 2.89, p < 0.001). After accounting for competing MI and controlling for age, gender, BMI, systolic blood pressure, smoking habit, plasma cholesterol, antihypertensive treatment, heart rate, fibrinogen and C-reactive protein, incident HF was predicted by greater LV mass index, larger left atrium, lower systolic function, greater left atrial systolic force and urinary albumin/creatinine excretion. Risk of HF was reduced with more rapid LV relaxation and anti-hypertensive therapy. Diabetes increases hazard of HF by 66% (0.02 < p < 0.001). The effect of diabetes could be explained by the level of HbA1c.

CONCLUSIONS

Incident HF occurs more frequently in diabetes, independent of intercurrent MI, abnormal LV geometry, subclinical systolic dysfunction and indicators of less rapid LV relaxation, and is influenced by poor metabolic control. Identification of CV phenotype at high-risk for HF in diabetes should be advised.

Coffee consumption and the incidence of type 2 diabetes in men and women with normal glucose tolerance: the Strong Heart Study

BACKGROUND AND AIMS

It was reported that high coffee consumption was related to decreased diabetes risk. The aim of this study is to examine the association between coffee consumption and the incidence of type 2 diabetes in persons with normal glucose tolerance in a population with a high incidence and prevalence of diabetes.

METHODS AND RESULTS

In a prospective cohort study, information about daily coffee consumption was collected at the baseline examination (1989-1992) in a population-based sample of American Indian men and women 45-74 years of age. Participants with normal glucose tolerance (N = 1141) at the baseline examination were followed for an average of 7.6 years. The incidence of diabetes was compared across the categories of daily coffee consumption. The hazard ratios of diabetes related to coffee consumption were calculated using Cox proportional hazards models, adjusted for potential confounders. Levels of coffee consumption were positively related to levels of current smoking and inversely related to body mass index, waist circumference, female gender, and hypertension. Compared to those who did not drink coffee, participants who drank 12 or more cups of coffee daily had 67% less risk of developing diabetes during the follow-up (hazard ratio: 0.33, 95% confidence interval: 0.13, 0.81).

CONCLUSION

In this population, a high level of coffee consumption was associated with a reduced risk of deterioration of glucose metabolism over an average 7.6 years of follow-up. More work is needed to understand whether there is a plausible biological mechanism for this observation.

Genome-wide linkage scan for plasma high density lipoprotein cholesterol, apolipoprotein A-1 and triglyceride variation among American Indian populations: the Strong Heart Family Study

BACKGROUND

Recent studies have identified chromosomal regions linked to variation in high density lipoprotein cholesterol (HDL-C), apolipoprotein A-1 (apo A-1) and triglyceride (TG), although results have been inconsistent and previous studies of American Indian populations are limited.

OBJECTIVE

In an attempt to localise quantitative trait loci (QTLs) influencing HDL-C, apo A-1 and TG, we conducted genome-wide linkage scans of subjects of the Strong Heart Family Study.

METHODS

We implemented analyses in 3484 men and women aged 18 years or older, at three study centres.

RESULTS

With adjustment for age, sex and centre, we detected a QTL influencing both HDL-C (logarithm of odds (LOD) = 4.4, genome-wide p = 0.001) and apo A-1 (LOD = 3.2, genome-wide p = 0.020) nearest marker D6S289 at 6p23 in the Arizona sample. Another QTL influencing apo A-1 was found nearest marker D9S287 at 9q22.2 (LOD = 3.0, genome-wide p = 0.033) in the North and South Dakotas. We detected a QTL influencing TG nearest marker D15S153 at 15q22.31 (LOD = 4.5 in the overall sample and LOD = 3.8 in the Dakotas sample, genome-wide p = 0.0044) and when additionally adjusted for waist, current smoking, current alcohol, current oestrogen, lipid treatment, impaired fasting glucose, and diabetes, nearest marker D10S217 at 10q26.2 (LOD = 3.7, genome-wide p = 0.0058) in the Arizona population.

CONCLUSIONS

The replication of QTLs in regions of the genome that harbour well known candidate genes suggest that chromosomes 6p, 9q and 15q warrant further investigation with fine mapping for causative polymorphisms in American Indians.

Metabolic syndrome and left ventricular hypertrophy in the prediction of cardiovascular events: the Strong Heart Study

BACKGROUND AND AIMS

Metabolic syndrome (MetS) is associated with increased prevalence of echocardiographic LV hypertrophy (LVH), a potent predictor of cardiovascular (CV) outcome. Whether MetS increases risk of CV events independently of presence of LVH has never been investigated. It is also unclear whether LVH predicts CV risk both in the presence and absence of MetS.

METHODS AND RESULTS

Participants in the 2nd Strong Heart Study examination without prevalent coronary heart disease, congestive heart failure or renal insufficiency (plasma creatinine >2.5mg/dL) were studied (n=2758; 1746 women). MetS was defined by WHO criteria. Echocardiographic LV hypertrophy was defined using population-specific cut-point value for LV mass index (>47.3g/m(2.7)). After controlling for age, sex, LDL-cholesterol, smoking, plasma creatinine, diabetes, hypertension and obesity, participants with MetS had greater probability of LVH than those without MetS (OR=1.55 [1.18-2.04], p<0.002). Adjusted hazard of composite fatal and non-fatal CV events was greater when LVH was present, in participants without (HR=2.03 [1.33-3.08]) or with MetS (HR=1.64 [1.31-2.04], both p<0.0001), with similar adjusted population attributable risk (12% and 14%). After adjustment for LVH, risk of incident CV events remained 1.47-fold greater in MetS (p<0.003), an effect, however, that was not confirmed when diabetic participants were excluded.

CONCLUSION

LVH is a strong predictor of composite 8-year fatal and non-fatal CV events either in the presence or in the absence of MetS and accounts for a substantial portion of the high CV risk associated with MetS.

Sex-specific interaction between APOE genotype and carbohydrate intake affects plasma HDL-C levels: the Strong Heart Family Study

Low plasma levels of high-density lipoprotein cholesterol (HDL-C) are identified as a risk factor for cardiovascular disease (CVD). Sexual dimorphism, however, is widely reported in both HDL-C and CVD, with the underlying explanations of these sexual differences not fully understood. HDL-C is a complex trait influenced by both genes and dietary factors. Here we examine evidence for a sex-specific effect of APOE and the macronutrient carbohydrate on HDL-C, triglycerides (TG) and apoprotein A-1 (ApoA-1) in a sample of 326 male and 423 female participants of the Strong Heart Family Study (SHFS). Using general estimating equations in SAS to account for kinship correlations, stratifying by sex, and adjusting for age, body mass index (BMI) and SHS center, we examine the relationship between APOE genotype and carbohydrate intake on circulating levels of HDL-C, TG, and ApoA-1 through a series of carbohydrate-by-sex interactions and stratified analyses. APOE-by-carbohydrate intake shows significant sex-specific effects. All males had similar decreases in HDL-C levels associated with increased carbohydrate intake. However, only those females with APOE-4 alleles showed significantly lower HDL-C levels as their percent of carbohydrate intake increased, while no association was noted between carbohydrate intake and HDL-C in those females without an APOE-4 allele. These findings demonstrate the importance of understanding sex differences in gene-by-nutrient interaction when examining the complex architecture of HDL-C variation.

Allexivirus transmitted by eriophyid mites in garlic plants

Viruses in garlic plants (Allium sativum L.) have accumulated and evolved over generations, resulting in serious consequences for the garlic trade around the world. These viral epidemics are also known to be caused by aphids and eriophyid mites (Aceria tulipae) carrying Potyviruses, Carlaviruses, and Allexiviruses. However, little is known about viral epidemics in garlic plants caused by eriophyid mites. Therefore, this study investigated the infection of garlic plants with Allexiviruses by eriophyid mites. When healthy garlic plants were cocultured with eriophyid mites, the leaves of the garlic plants developed yellow mosaic strips and became distorted. In extracts from the eriophyid mites, Allexiviruses were observed using immunosorbent electron microscopy (ISEM). From an immunoblot analysis, coat proteins against an Allexivirus garlic-virus antiserum were clearly identified in purified extracts from collected viral-infected garlic plants, eriophyid mites, and garlic plants infected by eriophyid mites. A new strain of GarV-B was isolated and named GarV-B Korea isolate 1 (GarV-B1). The ORF1 and ORF2 in GarV-B1 contained a typical viral helicase, RNA-directed RNA polymerase (RdRp), and triple gene block protein (TGBp) for viral movement between cells. The newly identified GarV-B1 was phylogenetically grouped with GarV-C and GarV-X in the Allexivirus genus. All the results in this study demonstrated that eriophyid mites are a transmitter insect species for Allexiviruses.

Linkage analysis of LDL cholesterol in American Indian populations: the Strong Heart Family Study

Previous studies have demonstrated that low density lipoprotein cholesterol (LDL-C) concentration is influenced by both genes and environment. Although rare genetic variants associated with Mendelian causes of increased LDL-C are known, only one common genetic variant has been identified, the apolipoprotein E gene (APOE). In an attempt to localize quantitative trait loci (QTLs) influencing LDL-C, we conducted a genome-wide linkage scan of LDL-C in participants of the Strong Heart Family Study (SHFS). Nine hundred eighty men and women, age 18 years or older, in 32 extended families at three centers (in Arizona, Oklahoma, and North and South Dakota) were phenotyped for LDL-C concentration and other risk factors. Using a variance component approach and the program SOLAR, and after accounting for the effects of covariates, we detected a QTL influencing LDL-C on chromosome 19, nearest marker D19S888 at 19q13.41 [logarithm of odds (LOD) = 4.3] in the sample from the Dakotas. This region on chromosome 19 includes many possible candidate genes, including the APOE/C1/C4/C2 gene cluster. In follow-up association analyses, no significant evidence for an association was detected with the APOE*2 and APOE*4 alleles (P = 0.76 and P = 0.53, respectively). Suggestive evidence of linkage to LDL-C was detected on chromosomes 3q, 4q, 7p, 9q, 10p, 14q, and 17q. These linkage signals overlap positive findings for lipid-related traits and harbor plausible candidate genes for LDL-C.

Catalyzed ozonation process with GAC and metal doped-GAC for removing organic pollutants

The purpose of this study was to investigate the catalytic role of granular activated carbon (GAC), and metal (Mn or Fe) doped-GAC, on the transformation of ozone into more reactive secondary radicals, such as hydroxyl radicals (*OH), for the treatment of wastewater. The GAC doped with Mn showed the highest catalytic performance in terms of ozone decomposition into OH radicals. Likewise, activated carbon alone accelerated the ozone decomposition, resulting in the formation of *OH radicals. In the presence of promoters, the ozone depletion rate was enhanced further by the Mn-GAC catalyst system, even under aqueous acidic pH conditions.

Evidence for joint action of genes on diabetes status and CVD risk factors in American Indians: the strong heart family study

OBJECTIVES

Previous research among American Indians of the strong heart family study (SHFS) has demonstrated significant heritabilities for CVD risk factors and implicated diabetes as an important predictor of several of the phenotypes. Moreover, we recently demonstrated that genetic effects on CVD risk factors differed in diabetic and nondiabetic individuals. In this paper, we investigated whether a significant genetic influence on diabetes status could be identified, and whether there is evidence for joint action of genes on diabetes status and related CVD risk factors.

METHODS AND RESULTS

Approximately 950 men and women, age 18 or older, in 32 extended families, were examined between 1997 and 1999. We estimated the effects of genes and environmental covariates on diabetes status using a threshold model and a maximum likelihood variance component approach. Diabetes status exhibited a residual heritability of 22% (h2=0.22). We also estimated the genetic and environmental correlations between diabetes susceptibility and eight risk factors for CVD. All eight CVD risk factors displayed significant genetic correlations with diabetes status (BMI (rhoG=0.55), fibrinogen (rhoG=0.40), HDL-C (rhoG=-0.37), ln triglycerides (rhoG=0.65), FAT (rhoG=0.38 ), PAI-1 (rhoG=0.67), SBP (rhoG=0.57), and WHR (rhoG=0.58)). Three of eight traits (HDL-C (rhoE=-0.32), ln triglycerides (rhoE=0.33), and fibrinogen (rhoE=0.20)) displayed significant environmental correlations with diabetes status.

CONCLUSIONS

These findings suggest that in the context of a high prevalence of diabetes, still unidentified diabetes genes may play an important role in influencing variation in CVD risk factors.

Recruitment of American Indians in epidemiologic research: the Strong Heart Study

This paper describes the methods used to recruit American Indian (AI) populations for the Strong Heart Study (SHS), a community-based study of cardiovascular disease (CVD) and its risk factors in AI men and women. Recruitment strategies included personal contact by recruiters and drivers/recruiters in remote areas, SHS staff participation in community activities, and mass media. A total of 4,549 participants aged 45-74 years were recruited from 13 American Indian tribes and communities. Overall participation rates were 72&percnt, 55&percnt, and 62&percnt, respectively, for the three study centers (Arizona, the Dakotas, and Oklahoma). Participant feedback and educational material related to risk factor reduction and promoting a healthy lifestyle were emphasized. Participants were likely to be female, young, and nonsmokers. Barriers to recruitment included lack of telephones in a large proportion of households, conflicting beliefs about health/health care/research, fears, taboos, and occasional rumors about study examination procedures. Participants were referred for follow-up of health problems detected by the study. The strong commitment of the participating communities helped to insure the success of the SHS, which can be considered a model for recruitment in future American Indian population-based studies. Success was facilitated by the use of a variety of recruitment techniques.

Prevalence and correlates of mitral valve prolapse in a population-based sample of American Indians: the Strong Heart Study

PURPOSE

Mitral valve prolapse is heritable and occurs frequently in the general population despite associations with mitral regurgitation and infective endocarditis, suggesting that selective advantages might be associated with mitral valve prolapse.

SUBJECTS AND METHODS

Clinical examination and 2-dimensional and color Doppler echocardiography were performed in 3340 American Indian participants in the Strong Heart Study.

RESULTS

Mitral valve prolapse (clear-cut billowing of one or both mitral leaflets across the mitral anular plane in 2-dimensional parasternal long-axis recordings or >2-mm late systolic posterior displacement of mitral leaflets by M mode) occurred in 37 (1.8%) of 2077 women and 20 (1.6%) of 1263 men (P = 0.88); 32 (3.5%) of 907 patients with normal glucose tolerance, 11 (2.3%) of 486 patients with impaired glucose tolerance, and 13 (0.7%) of 1735 patients with diabetes (P <0.0001). Participants with mitral valve prolapse had lower mean (+/- SD) body mass index (28 +/- 5 kg/m(2) vs. 31 +/- 6 kg/m(2), P = 0.001) and blood pressure (124/71 +/- 19/10 mm Hg vs. 130/75 +/- 21/10 mm Hg, P <0.05), as well as lower levels of fasting glucose, triglycerides, serum creatinine, and log urine albumin/creatinine ratio (all P <0.001), than did those without mitral valve prolapse, although all subjects were similar in age (60 +/- 8 years). Participants with mitral valve prolapse had lower ventricular septal (0.87 +/- 0.08 cm vs. 0.93 +/- 0.13 cm) and posterior wall thicknesses (0.82 +/- 0.08 cm vs. 0.87 +/- 0.10 cm), mass (38 +/- 7 g/m(2.7) vs. 42 +/- 11 g/m(2.7)), and relative wall thickness (0.33 +/- 0.04 vs. 0.35 +/- 0.05), and increased stress-corrected midwall shortening (all P <0.01). Mitral valve prolapse was associated with a higher prevalence of mild (16 of 57 [28%] vs. 614 of 3283 [19%]) and more severe mitral regurgitation (5 of 57 [9%] vs. 48 of 3283 [1%], P <0.0001). Regression analyses showed prolapse was associated with low ventricular relative wall thickness, high midwall function, and low urine albumin/creatinine ratio, independent of age, sex, body mass index, and diabetes.

CONCLUSIONS

Mitral valve prolapse is fairly common and is strongly associated with mitral regurgitation in the general population. However, it is also associated with lower body weight, blood pressure, and prevalence of diabetes; a more favorable metabolic profile and ventricular geometry; and better myocardial and renal function.

Fibrinogen and preclinical echocardiographic target organ damage: the strong heart study

Relations of fibrinogen to preclinical target organ damage, such as left ventricular hypertrophy, systolic dysfunction, and increased arterial stiffness while accounting for traditional risk factors, are unknown in a population-based sample free of clinically overt coronary heart disease. Therefore, we studied clinical and echocardiographic characteristics of 2709 American Indians participating in the Strong Heart Study without symptomatic atherosclerosis. The study sample was divided into tertiles of fibrinogen (cut-points, 3.24 and 3.83 g/L). Mean age, body mass index, proportion of women, and prevalences of hypertension and diabetes increased from the first to third tertile of fibrinogen. After adjustment for covariates, systolic and pulse pressures did not significantly differ among tertiles of fibrinogen, whereas diastolic pressure was slightly lower in the third than in lower tertiles of fibrinogen. HDL cholesterol was lower and plasma creatinine and urinary albumin/creatinine ratio was higher in the third tertile of fibrinogen. Left ventricular mass index, pulse pressure/stroke index, an estimate of arterial stiffness, and cardiac index were higher and left ventricular systolic function and total peripheral resistance were lower in the third than in two lower tertiles of fibrinogen independent of major covariates. In multiple regression analyses, left ventricular mass and pulse pressure/stroke index were positively associated with, and stress-corrected midwall shortening negatively associated with fibrinogen, independent of major covariates. Participants with fibrinogen >3.83 g/L were more likely to have at least 1 preclinical cardiovascular abnormality such as left ventricular hypertrophy, elevated arterial stiffness, or systolic myocardial dysfunction independent of covariates including renal dysfunction (adjusted odds ratio, 1.38; P<0.001). Thus, in a population sample of adults without clinically overt coronary heart disease, elevated fibrinogen is an independent correlate of prognostically relevant cardiovascular target organ damage.

The incidence of visual impairment and its determinants in the WHO Multinational Study of Vascular Disease in Diabetes

AIMS/HYPOTHESIS

Incidence of severe visual impairment and the ultimate prevalence of all grades of impairment were estimated in the 10 centres of the WHO Multinational Study of Vascular Disease in Diabetes (WHO MSVDD) participating in the follow-up.

METHODS

Visual function was ascertained at follow-up in 2994 (77.9 %) of the 3845 eligible participating survivors of the 4709 originally recruited for the WHO MSVDD using the same baseline enquiry method. The associations between incident severe visual impairment, follow-up prevalence of all grades of impairment and baseline risk factors were examined by univariate and stepwise multiple logistic regression analysis.

RESULTS

Overall, 8.4 year incidence of severe visual impairment was 1.94 % and showed statistically significant univariate correlations with age at diagnosis, diabetes duration, systolic blood pressure, fasting blood glucose and cholesterol, insulin treatment and strongly with baseline retinopathy. Baseline retinopathy, systolic pressure and cholesterol were statistically significant in multivariable analysis. Differences between centres (0.3% to 3.45%) were not significant. Ultimate prevalence of all grades of impairment differed between centres and within almost all of them was correlated in multivariable analysis with baseline retinopathy and proteinuria.

CONCLUSION/INTERPRETATION

Comparisons of incident severe visual impairment between centres are restricted by selective mortality, low incidence rates and relatively small numbers in each centre but before retinopathy, baseline systolic pressure and cholesterol predicted severe visual impairment. Follow-up prevalence of all degrees of impairment varied among centres and were associated with prior retinopathy and renal disease at baseline.

Vascular disease in younger-onset diabetes: comparison of European, Asian and American Indian cohorts of the WHO Multinational Study of Vascular Disease in Diabetes

AIMS/HYPOTHESIS

This study compared the incidence of vascular disease in subjects with younger-onset diabetes from different ethnic groups.

METHODS

The incidence of vascular disease endpoints has been studied in a sub-group (n = 994) of participants of the World Health Organization Multinational Study of Vascular Disease in Diabetes (WHO MSVDD) who had younger-onset diabetes (diagnosed before the age of 30 years). The study participants have been divided into European (n = 631), Asian (n = 84) and American Indian (n = 91) cohorts.

RESULTS

For Type I (insulin-dependent) and Type II (non-insulin-dependent) diabetes mellitus, American Indian men had a higher incidence of lower-extremity amputation and renal failure than the other cohorts, whereas European women had a higher incidence of angina than other cohorts. American Indians also had a higher incidence of any retinopathy, clinical proteinuria and albuminuria than the European and Asian cohorts.

CONCLUSION/INTERPRETATION

This study confirms the high burden of large and small-vessel disease complications manifest in American Indian people with younger-onset diabetes.

The appearance of retinopathy and progression to proliferative retinopathy: the WHO Multinational Study of Vascular Disease in Diabetes

AIMS/HYPOTHESIS

We aimed to estimate incidences of any retinopathy and proliferative diabetic retinopathy (PDR) by direct ophthalmoscopy and relate them to baseline risk factors in re-examined diabetic survivors from 10 centres of the WHO Multinational Study of Vascular Disease in Diabetes.

METHODS

After a mean follow-up of 8.4years (11.7 years in Oklahoma), 2877 (71.6%) survivors were resubmitted to standardised direct ophthalmoscopy as at baseline. The presence of any retinopathy and PDR were recorded at each centre and their incidence estimated in those without retinopathy and PDR at baseline. The independent associations of these incidences with baseline risk factors are expressed as odds ratios derived from multiple logistic regression analyses, within individual centres (which included fasting plasma glucose in 8 and triglyceride in 5) and in pooled data.

RESULTS

Of the 4662 original patients, 465 (10.4%) of those without and 77 (43.0%) of those with baseline PDR had died (p < 0.001). Any retinopathy was newly reported at follow-up in 47.7 % and PDR in 9.7 % of those free of them at baseline, with reported incidences varying substantially among centres. Incident retinopathy appeared earlier in the known course of diabetes but incidence rates rose more slowly with duration in patients with Type II (non-insulin-dependent) diabetes mellitus than in those with Type I (insulin-dependent) diabetes mellitus. In pooled data and in some individual centres, any retinopathy incidence gave significantly positive odds ratios with age, diabetes duration, systolic pressure, plasma cholesterol, BMI, insulin treatment and proteinuria, and with fasting plasma glucose in the centres where it was measured. Positive odds ratios for PDR were similarly obtained for age, duration, insulin treatment, cholesterol, proteinuria and fasting glycaemia. Smoking status odds ratios were negative for both outcomes.

CONCLUSION/INTERPRETATION

Incidence of ophthalmoscopically ascertained any retinopathy varied about twofold and of PDR about threefold among centres. Although, in part attributable to differences between observers, variation in incidence in all centres and in some cases within centres was associated with a number of baseline risk factors. Such associations are not likely due to observer variation or selection biases and emerged despite the imprecision of clinical ophthalmoscopy. Improved detection and control of these risk factors should reduce the impact of diabetic retinopathy and its consequences.

Risk factors, ethnic differences and mortality associated with lower-extremity gangrene and amputation in diabetes. The WHO Multinational Study of Vascular Disease in Diabetes

AIMS/HYPOTHESIS

We aimed to examine geographic differences, risk factors and mortality associated with amputation.

METHODS

Data from 10 of the original 14 centres of the WHO Multinational Study of Vascular Disease in Diabetes were used. This included 3443 men and women aged 35 to 55 years at baseline.

RESULTS

Incidences of amputation, adjusted for sex and duration in Type I (insulin-dependent) diabetes mellitus, were 31.0, 8.2, 3.5 and 1.0 per 1,000 person years in the American Indian, Cuban, European and East Asian centres respectively. In Type II (non-insulin-dependent) diabetes mellitus, incidences of amputation were 9.7, 2.0, 2.5 and 0.7 per 1000 person years in the American Indian, Cuban, European and East Asian centres respectively. Key risk factors for amputation included glucose, triglyceride, and retinopathy, and were similar for American Indians and Europeans. The age, duration and sex adjusted relative risk for amputation in American Indians compared with Europeans was 11.48 (95% CI 3.56, 36.98) in Type I diabetes and 3.86 (95 % CI 2.36, 6.32) in Type II diabetes. Adjusting for heart disease, retinopathy, proteinuria, glucose, blood pressure and triglyceride attenuated these relative risks to 10.83 (95 % CI 3.20, 36.65) and 3.15 (1.91, 5.20) in Type I and Type II diabetes respectively. Amputation doubled mortality rates in all groups.

CONCLUSION/INTERPRETATION

Vascular complications and their risk factors are themselves risk factors for amputation in both Type I and Type II diabetes and are common to several geographical regions worldwide. However, reasons for differences between geographical regions and the degree to which different health care systems could be responsible is not clear.

Increased urinary albumin excretion and its associations in the WHO Multinational Study of Vascular Disease in Diabetes

AIM/HYPOTHESIS

We aimed to determine variations in the prevalence of increased urinary albumin excretion, associated risk factors and complications in patients with diabetes participating in the WHO Multinational Study of Vascular Disease in Diabetes follow-up.

METHODS

Urinary albumin to urinary creatinine ratios were measured centrally in 2,033 of the 2,550 (79.7%) re-examined patients from eight centres in seven countries and the frequency of microalbuminuria and macroalbuminuria and their associations with risk factors and complications were examined.

RESULTS

Macroalbuminuria prevalence (overall 15.6%) varied tenfold (3-37%) among centres, was higher in American Indian and Asian centres and not clearly related to type of diabetes. Microalbuminuria (overall 19.7 %) varied less (12-31%). Increased albumin excretion was related overall to baseline fasting plasma glucose in the pooled group in whom it was measured and to increased arterial pressure, insulin use, coronary heart disease, lower extremity amputation, retinopathy and stroke in most centres.

CONCLUSION/INTERPRETATION

Centres varied widely in the prevalence of increased albumin excretion but associations with risk factors and vascular complications were generally similar in most centres and in both major types of diabetes with ethnic and genetic differences probably contributing.

Vascular disease prevalence in diabetic patients in China: standardised comparison with the 14 centres in the WHO Multinational Study of Vascular Disease in Diabetes

AIMS/HYPOTHESIS

Rates of vascular complications of diabetes in a cohort of mainland Chinese patients with diabetes, ascertained and examined by similar methodology, are compared with those of the WHO Multinational Study of Vascular Disease in Diabetes (WHO MSVDD).

METHODS

The standardised procedures carried out in the WHO MSVDD were followed in assembling and examining a Chinese cohort of 447 diabetic patients recruited in Beijing and Tianjin [2].

RESULTS

Compared with the WHO MSVDD centres, the Chinese cohort was slightly older, had a shorter duration of known diabetes and had fewer insulin-treated patients. Arterial pressure, total blood cholesterol and body mass index were substantially lower. Large vessel disease rate for age, sex and duration adjusted data (17.9 % ) was about half that of the combined WHO MSVDD centres (33.5 % p < 0.001). However, retinopathy (47.4% vs 35.8% p < 0.001) and proteinuria (57.1 vs 24.9 % p < 0.001) rates were significantly higher.

CONCLUSION/INTERPRETATION

Relatively low arterial pressures and blood cholesterol are likely contributors to the notably low arterial disease rates in this Chinese diabetic cohort; they reflect low rates in the Chinese mainland general population and resemble the Tokyo and Hong Kong centres of the WHO MSVDD. The high rates of retinopathy and proteinuria could relate to later diagnosis, degree of hyperglycaemia and/or increased susceptibiltiy to microangiopathy.

An analysis of serial Minnesota ECG code changes in the London cohort of the WHO Multinational Study of Vascular Disease in Diabetes

AIMS/HYPOTHESIS

Deterioration and improvement in the electrocardiogram are important outcomes in cardiovascular disease progression assessment. We used a sample of serial records from the WHO Multinational Study of Vascular Disease in Diabetes (WHO MSVDD) to assess Minnesota coding variability.

METHODS

A constructed subsample of 118 of the 352 paired (baseline and follow-up) and previously Minnesota-coded ECG records from the London cohort was randomised and re-read independently of the first code (respectively 11 and 0.5 years later) by the same two coders. Detailed Minnesota codes were summary coded into groups 1 (CHD unlikely), 2 and 3 (CHD possible and probable, respectively).

RESULTS

Re-reading of the constructed sample for the baseline records (11 years later) generated 21 Summary code reassignments (2 unlikely to possible or probable; 19 possible or probable to unlikely); re-reading for the follow-up records (0.5 years later) generated only 8 summary code reassignments (21 vs 8p < 0.001) (3 unlikely to possible or probable; 4 possible or probable to unlikely; 1 probable to possible). Re-reading increased the estimated net ECG deterioration in the constructed sample from 11.8 % to 25.4%. Consistency analysis showed most variability in marginal baseline abnormalities.

CONCLUSION/INTERPRETATION

Coding variability is now small though re-reading suggests some time-dependent coding drift. Relative over-reading at baseline suggests that the change reported in the complete WHO MSVDD cohort at follow-up was underestimated and that almost all of the reported ECG deterioration and about half of the reported ECG 'improvement' was real.

Hypertension treatment patterns in American Indians: the strong heart study

Pharmacologic treatment patterns for hypertensive American Indians from 13 communities in Arizona, Oklahoma, South Dakota, and North Dakota were assessed. Participants (2254 women and 1384 men, aged 48 to 79 years) completed a clinical examination between July 1993 and December 1995. The mean of two blood pressure (BP) measurements and detailed medication histories were obtained. The observed prevalence of hypertension was 46.7% (n=1698). In participants taking antihypertensive medications (n=1114), four principal drug classes were evaluated: diuretics, calcium channel blocking agents, beta-blocking agents, and angiotensin-converting enzyme (ACE) inhibitors. Among treated hypertensive participants, 71.4%, 24.6%, and 4.0% received one, two, and three medications, respectively. Among single drug regimens, ACE inhibitors (n=340) were used most often (49.4%), with calcium channel blocking agents and diuretics accounting for 24.2% and 19.9%, respectively. Although multiple drug class therapies varied, the combination of a diuretic and ACE inhibitor (n=120) accounted for 47.4% of dual therapy use. Hypertension control (SBP < 140 mm Hg, DBP < 90 mm Hg) rates were highest for those on dual therapies (65.4%), followed by participants on single (53.8%) and triple (43.6%) therapies. Among monotherapies, diuretics exhibited the best overall hypertension control rate in both diabetics (63.0%) and nondiabetics (68.0%), versus 47% to 61% for other remaining agents. The frequent use of ACE inhibitors, used singly or in combination, reflects the high prevalence of diabetes among American Indians. ACE inhibitors, combined with diuretics, were particularly useful in achieving BP control in this population.

Risk factors for renal failure: the WHO Mulinational Study of Vascular Disease in Diabetes

AIMS/HYPOTHESIS

We aimed to examine risk factors for, and differences in, renal failure in diabetic patients from 10 centres.

METHODS

Risk factors for renal failure were examined in 3,558 diabetic patients who did not have renal disease at baseline in the WHO Multinational Study of Vascular Disease in Diabetes (WHO MSVDD).

RESULTS

In 959 subjects with Type I (insulin-dependent) diabetes mellitus and 2,559 with Type II (non-insulin-dependent) diabetes mellitus, the average follow-up was 8.4 years (+/- 2.7). By the end of the follow-up period 53 patients in the Type I diabetic group and 134 patients in the Type II diabetic group had developed renal failure (incidence rate 6.3:1,000 person years). Increasing age and duration of diabetes were associated with renal failure in Type II and Type I diabetes. In Type II diabetes duration of diabetes was a more important risk factor than age. In both Type I and Type II diabetic retinopathy and proteinuria were strongly associated with renal failure. Systolic blood pressure was associated with renal failure in Type I but not in Type II diabetic patients. ECG abnormalities at baseline, self-reported smoking and cholesterol were not associated with renal failure. Triglycerides were measured in a subset of centres. Among those with Type II, but not Type I diabetes, triglycerides were associated with renal failure independently of systolic blood pressure, proteinuria or retinopathy. In Type II diabetes fasting plasma glucose was associated with renal failure independently of other risk factors.

CONCLUSION/INTERPRETATION

We have confirmed the role of proteinuria and retinopathy as markers of renal failure and the importance of hyperglycaemia in renal failure in Type I and Type II diabetes. Plasma triglycerides seem to be an important predictor of renal failure in Type II diabetes. In Type I diabetes systolic blood pressure is an important predictor of renal failure.

Follow-up of the WHO Multinational Study of Vascular Disease in Diabetes: general description and morbidity

AIMS

The incidence of retinal, renal and cardiovascular complications and their relation to baseline risk factors was documented in this follow-up study of 10 of the 14 original centres of the WHO Multinational Study of Vascular Disease in Diabetes (WHO MSVDD).

METHODS

The incidence of specified items of vascular disease and some associated risk factors was ascertained after 7 to 9 years (11-12 years in Oklahoma, USA) follow-up, re-using baseline examination methodology in 3165 patients (66.9 %) and, through secondary information in 717 (15.2%) of the 4729 original patients, of whom 540 (11.4%) had died and 307 (6.5 %) were untraceable.

RESULTS

During follow-up, approximately one third of the patients developed hypertension and one third started insulin. Coronary heart disease incidence varied 10 to 20-fold among centres as did limb amputation rates. Inter-centre differences in incident retinopathy and severe visual impairment were smaller but incident clinical proteinuria and renal failure varied markedly. Vascular disease incidence of all categories was high in Native Americans though coronary heart disease incidence was relatively low in Pima Indians and absolutely low in Hong Kong and Tokyo patients. Specific vascular events and their relation with baseline risk factors are analysed in accompanying papers, summarised in the Epilogue.

CONCLUSION/INTERPRETATION

These 10 centres reported very different incidence rates of vascular complications. Observer variation, selection biases and competing causes of mortality contributed to these differences but their validity is supported by the more objective outcome indicators. The following papers also suggest that baseline factors such as raised arterial pressure, cholesterol and fasting glucose (in the centres where it was measured) were important and potentially reversible predictors of risk.

Separate and joint effects of systemic hypertension and diabetes mellitus on left ventricular structure and function in American Indians (the Strong Heart Study)

Although the association of systemic hypertension (SH) with diabetes mellitus (DM) is well established, the cardiac features and hemodynamic profile of patients with SH and DM diagnosed by American Diabetes Association criteria have not been elucidated. To address this issue, echocardiograms were analyzed in 1,025 American Indian participants of the Strong Heart Study with neither DM nor SH, 642 with DM alone, 614 with SH alone, and 874 with SH and DM. In analyses that adjusted for age, gender, body mass index, and heart rate, DM and SH were associated with increased left ventricular (LV) wall thicknesses, with the greatest impact of DM on LV relative wall thickness and of the combination of DM and SH on LV mass (both p <0.001). LV fractional shortening was reduced with SH and SH + DM, midwall shortening was reduced with DM, SH, and their combination, and was reduced in both diabetic groups compared with their nondiabetic counterparts (p <0.001). DM alone was associated with lower measures of LV pump performance (stroke volume, cardiac output, and their indexes) than SH alone. Pulse pressure/stroke index, an indirect measure of arterial stiffness, was elevated in participants with DM or SH alone and most in those with both conditions. There were progressive increases from the reference group to DM alone, SH alone, and DM + SH with regard to prevalences of LV hypertrophy (12% to 19%, 29% and 38%) and subnormal LV myocardial function (7% to 10%, 11% and 18%, both p <0.001). In conclusion, DM and SH each have adverse effects on LV geometry and function, and the combination of SH and DM results in the greatest degree of LV hypertrophy, myocardial dysfunction, and arterial stiffness.

Relationship of impaired glucose tolerance to left ventricular structure and function: The Strong Heart Study

BACKGROUND

We have identified increased left ventricular (LV) mass, wall thickness, relative wall thickness, and reduced systolic function in diabetic individuals after adjusting for blood pressure and body mass index. However, the cardiovascular correlates of impaired glucose tolerance (IGT), a precursor of diabetes, are unknown.

METHODS

We compared LV measurements between 457 American Indian participants in the Strong Heart Study with IGT (34% men) by World Health Organization criteria and 888 participants (49% men) with normal glucose tolerance.

RESULTS

Participants with IGT were older (60 vs 59 years, P < .01), more overweight (body mass index, 32 +/- 6 vs 29 +/- 5 g/m(2)), and had higher systolic blood pressure (129 +/- 20 vs 124 +/- 18 mm Hg, P < .001) and heart rate (67 +/- 10 vs 66 +/- 11 beats/min, P = .011). In univariate analyses, women but not men with IGT had higher LV mass (mean, 150 vs 138 g, P < .001) and cardiac index (2.6 vs 2.5 L/min/m(2), P < .05). LV wall thicknesses and relative wall thickness were greater in women and men with IGT. Regression analysis, adjusting for multiple covariates in the entire study population, identified independent associations of IGT with higher LV relative wall thicknesses, LV mass/height(2.7), and cardiac output/height(1.83).

CONCLUSIONS

IGT is associated with increased LV wall thickness, mass, and cardiac output independent of effects of relevant covariates.

Reference values for echocardiographic measurements in urban and rural populations of differing ethnicity: the Strong Heart Study

Discrepancies in reported reference values for left ventricular (LV) dimensions and mass may be due to imaging errors with early echocardiographic methods or effects of subject characteristics and inclusion criteria. To determine whether contemporary echocardiographic methods provide stable normal limits for left ventricular measurements in different populations, M-mode/2-dimensional echocardiography was applied in 176 American Indian participants in the Strong Heart Study and 237 New York City residents who were clinically normal. No consistent difference in any measure of LV size or function existed between populations. Upper normal limits (98th percentile) for LV mass were 96 g/m(2) in women and 116 g/m(2) in men and 3.27 cm/m for LV chamber diameter normalized for height. Thus contemporary M-mode/2D echocardiography provides reference ranges for LV measurements that approximate necropsy measurements and have acceptable stability in apparently normal white, African-American/Caribbean, and American Indian populations.

The impact of diabetes on left ventricular filling pattern in normotensive and hypertensive adults: the Strong Heart Study

OBJECTIVES

We sought to determine the effect of diabetes mellitus (DM) on left ventricular (LV) filling pattern in normotensive (NT) and hypertensive (HTN) individuals.

BACKGROUND

Diastolic abnormalities have been extensively described in HTN but are less well characterized in DM, which frequently coexists with HTN.

METHODS

We analyzed the transmitral inflow velocity profile at the mitral annulus in four groups from the Strong Heart Study: NT-non-DM (n = 730), HTN-non-DM (n = 394), NT-DM (n = 616) and HTN-DM (n = 671). The DM subjects were further divided into those with normal filling pattern (n = 107) and those with abnormal relaxation (AbnREL) (n = 447).

RESULTS

The peak E velocity was lowest in HTN-DM, intermediate in NT-DM and HT-non-DM and highest in the NT-non-DM group (p < 0.001), with a reverse trend seen for peak A velocity (p < 0.001). In multivariate analysis, E/A ratio was lowest in HTN-DM and highest in NT-non-DM, with no difference between NT-DM and HTN-non DM (p < 0.001). Likewise, mean atrial filling fraction and deceleration time were highest in HTN-DM, followed by HTN-non-DM or NT-DM and lowest in NT-non-DM (both p < 0.05). Among DM subjects, those with AbnREL had higher fasting glucose (p = 0.03) and hemoglobin A1C (p = 0.04).

CONCLUSIONS

Diabetes mellitus, especially with worse glycemic control, is independently associated with abnormal LV relaxation. The severity of abnormal LV relaxation is similar to the well-known impaired relaxation associated with HTN. The combination of DM and HTN has more severe abnormal LV relaxation than groups with either condition alone. In addition, AbnREL in DM is associated with worse glycemic control.

Comparison of diagnosis of early retinal lesions of diabetic retinopathy between a computer system and human experts

OBJECTIVE

To investigate whether a computer vision system is comparable with humans in detecting early retinal lesions of diabetic retinopathy using color fundus photographs.

METHODS

A computer system has been developed using image processing and pattern recognition techniques to detect early lesions of diabetic retinopathy (hemorrhages and microaneurysms, hard exudates, and cotton-wool spots). Color fundus photographs obtained from American Indians in Oklahoma were used in developing and testing the system. A set of 369 color fundus slides were used to train the computer system using 3 diagnostic categories: lesions present, questionable, or absent (Y/Q/N). A different set of 428 slides were used to test and evaluate the system, and its diagnostic results were compared with those of 2 human experts-the grader at the University of Wisconsin Fundus Photograph Reading Center (Madison) and a general ophthalmologist. The experiments included comparisons using 3 (Y/Q/N) and 2 diagnostic categories (Y/N) (questionable cases excluded in the latter).

RESULTS

In the training phase, the agreement rates, sensitivity, and specificity in detecting the 3 lesions between the retinal specialist and the computer system were all above 90%. The kappa statistics were high (0.75-0.97), indicating excellent agreement between the specialist and the computer system. In the testing phase, the results obtained between the computer system and human experts were consistent with those of the training phase, and they were comparable with those between the human experts.

CONCLUSIONS

The performance of the computer vision system in diagnosing early retinal lesions was comparable with that of human experts. Therefore, this mobile, electronically easily accessible, and noninvasive computer system, could become a mass screening tool and a clinical aid in diagnosing early lesions of diabetic retinopathy.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prevalence and correlates of mitral regurgitation in a population-based sample (the Strong Heart Study)

Evidence suggesting that mitral regurgitation (MR) may be induced by appetite suppressant medications heightens the importance of understanding the prevalence and correlates of MR, especially its relation to obesity, in population-based samples. MR was assessed by color Doppler echocardiography in 3,486 American Indian participants in the Strong Heart Study. Mild (1+) MR was present in 19.2%, moderate (2+) MR in 1.6%, moderately severe (3+) in 0.3%, and severe (4+) in 0.2% of participants. In univariate analyses, MR was unrelated to gender, diabetes, or lipid levels, but was more frequent in North/South Dakota (28.3%) than in Oklahoma (21.6%) or Arizona (14.3%) (p <0.001). MR was related to lower body mass index (BMI) (p <0.001), older age (p <0.001), higher systolic blood pressure (p = 0.003), higher serum creatinine (p <0.001), and higher urine albumin/creatinine ratio (p <0.001). In multivariate analyses, the presence and severity of MR were independently associated with higher serum creatinine, lower BMI, mitral stenosis, prior myocardial infarction, female gender, mitral valve prolapse and, variably, older age. In conclusion, MR, mostly mild, is detected by color Doppler echocardiography in >20% of middle-aged and older adults. MR is independently associated with female gender, lower BMI, older age, and renal dysfunction, as well as with prior myocardial infarction, mitral stenosis, and mitral valve prolapse. It is not related to dyslipidemia or diabetes.

Sleep-disordered breathing and cardiovascular disease: cross-sectional results of the Sleep Heart Health Study

Disordered breathing during sleep is associated with acute, unfavorable effects on cardiovascular physiology, but few studies have examined its postulated association with cardiovascular disease (CVD). We examined the cross-sectional association between sleep- disordered breathing and self-reported CVD in 6,424 free-living individuals who underwent overnight, unattended polysomnography at home. Sleep-disordered breathing was quantified by the apnea-hypopnea index (AHI)-the average number of apneas and hypopneas per hour of sleep. Mild to moderate disordered breathing during sleep was highly prevalent in the sample (median AHI: 4.4; interquartile range: 1.3 to 11.0). A total of 1,023 participants (16%) reported at least one manifestation of CVD (myocardial infarction, angina, coronary revascularization procedure, heart failure, or stroke). The multivariable-adjusted relative odds (95% CI) of prevalent CVD for the second, third, and fourth quartiles of the AHI (versus the first) were 0.98 (0.77-1.24), 1.28 (1.02-1.61), and 1.42 (1.13-1.78), respectively. Sleep-disordered breathing was associated more strongly with self-reported heart failure and stroke than with self-reported coronary heart disease: the relative odds (95% CI) of heart failure, stroke, and coronary heart disease (upper versus lower AHI quartile) were 2.38 (1.22-4.62), 1.58 (1.02- 2.46), and 1.27 (0.99-1.62), respectively. These findings are compatible with modest to moderate effects of sleep-disordered breathing on heterogeneous manifestations of CVD within a range of AHI values that are considered normal or only mildly elevated.

Congestive heart failure despite normal left ventricular systolic function in a population-based sample: the Strong Heart Study

In selected clinical series, > or = 50% of adults with congestive heart failure (CHF) do not have left ventricular (LV) systolic dysfunction. Little is known of the prevalence of this phenomenon in population samples. Therefore, clinical examination and echocardiography were used in the second examination of the Strong Heart Study (3,184 men and women, 47 to 81 years old) to identify 95 participants with CHF, 50 of whom had normal LV ejection fraction (EF) (> 54%), 19 of whom had mildly reduced EF (40% to 54%), and 26 of whom had EF < or = 40%. Compared with those with no CHF, participants with CHF and no, mild, or severe decrease in EF had higher creatinine levels (2.34 to 2.85 vs 1.01 mg/dl, p < 0.001) and higher prevalences of diabetes (60% to 70% vs 50%) and hypertension (75% to 96% vs 46%, p < 0.05). Compared with those with no CHF, participants with CHF and normal EF had prolonged deceleration time (233 vs 204 ms, p < 0.05) and a reduced E/A, whereas those with CHF and EF < or = 40% had short deceleration time (158 ms, p < 0.05) and high E/A (1.70, p < 0.001); patients with CHF and normal EF had higher LV mass (98 vs 84 g/m2, p < 0.001) and relative wall thickness (0.37 vs 0.35, p < 0.05) than those without CHF. Patients with CHF with normal EF were, compared with those without CHF or with CHF and EF < or = 40%, disproportionately women (mean 84% vs 63% and 42%, p < 0.001), older (mean 64 vs 60 years and 63 years, respectively, p < 0.01), had higher body mass index (mean 33.1 vs 31.0 and 27.7 kg/m2, p < 0.05), and higher systolic blood pressure (mean 137 vs 130 and 128 mm Hg, both p < 0.05). Thus, in a population-based sample, patients with CHF and normal LV EF were older and overweight, more often women, had renal dysfunction, impaired early diastolic LV relaxation, and concentric LV geometry, whereas patients with CHF and severe LV dysfunction were more often men, had lower body mass index, a restrictive pattern of LV filling, and eccentric LV hypertrophy.

A virtual reality system for hand acupuncture

A virtual reality system for the hand acupuncture treatment is proposed. The hand acupuncture, called sujichim, is mostly conducted at home and many people try to learn and apply it to the health care of their family. Using our system, a novice can easily perform the acupuncture by himself to improve his body condition. According to the experiments, our system is proved to be very effective and easy to use.

Effects of obesity and body fat distribution on lipids and lipoproteins in nondiabetic American Indians: The Strong Heart Study

OBJECTIVES

To examine the relationship between obesity and lipoprotein profiles and compare the effects of total obesity and central adiposity on lipids/lipoproteins in American Indians.

RESEARCH METHODS AND PROCEDURES

Participants were 773 nondiabetic American Indian women and 739 men aged 45 to 74 years participating in the Strong Heart Study. Total obesity was estimated using body mass index (BMI). Central obesity was measured as waist circumference. Lipoprotein measures included triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, apolipoprotein AI (apoAI), and apolipoprotein B (apoB). Partial and canonical correlation analyses were used to examine the associations between obesity and lipids/ lipoproteins.

RESULTS

Women were more obese than men in Arizona (median BMI 32.1 vs. 29.2 kg/m2) and South Dakota and North Dakota (28.3 vs. 28.0 kg/m2), but there was no sex difference in waist circumference. Men had higher apoB and lower apoAI levels than did women. In women, when adjusted for center, gender, and age, BMI was significantly related to HDL cholesterol (r = -0.24, p < 0.001). There was a significant but weak relation with apoAI (r = -0.14, p < 0.001). Waist circumference was positively related to triglycerides (r = 0.14, p < 0.001) and negatively related to HDL cholesterol (r = -0.23, p < 0.001) and apoAI (r = -0.13, p < 0.001). In men, BMI was positively correlated with triglycerides (r = 0.30, p < 0.001) and negatively correlated with HDL cholesterol (r = -0.35, p < 0.001) and apoAI (r = -0.23, p < 0.001). Triglycerides increased with waist circumference (r = 0.30, p < 0.001) and HDL cholesterol decreased with waist circumference (r = -0.36, p < 0.001). In both women and men there was an inverted U-shaped relationship between obesity and waist with LDL cholesterol and apoB. In canonical correlation analysis, waist circumference received a greater weight (0.86) than did BMI (0.17) in women. However, the canonical weights were similar for waist (0.46) and BMI (0.56) in men. Only HDL cholesterol (-1.02) carried greater weight in women, whereas in men, triglycerides (0.50), and HDL cholesterol (-0.64) carried a large amount of weight. All the correlation coefficients between BMI, waist circumference, and the first canonical variable of lipids/lipoproteins or between the individual lipid/lipoprotein variables and the first canonical variable of obesity were smaller in women than in men. Triglycerides and HDL cholesterol showed clinically meaningful changes with BMI and waist circumference in men. All lipid/lipoprotein changes in women in relation to BMI and waist circumference were minimal.

DISCUSSION

The main lipoprotein abnormality related to obesity in American Indians was decreased HDL cholesterol, especially in men. Central adiposity was more associated with abnormal lipid/lipoprotein profiles than general obesity in women; both were equally important in men.

Prevalence and correlates of aortic regurgitation in American Indians: the Strong Heart Study

OBJECTIVES

We sought to determine the prevalence and correlates of aortic regurgitation (AR) in a population-based sample group.

BACKGROUND

Concern over induction of AR by weight loss medication highlights the importance of assessing the prevalence and correlates of AR in unselected patient groups.

METHODS

Aortic regurgitation was assessed by color flow Doppler echocardiography in 3,501 American Indian participants age 47 to 81 years during the second Strong Heart Study.

RESULTS

Mild (1+) AR was present in 7.3%, 2+ AR in 2.4% and 3+ to 4+ AR in 0.3% of participants, more frequently in those > or =60 years old than in those <60 years old (14.4% vs. 5.8%, p<0.001); AR was unrelated to gender. Compared with participants without AR, those with mild AR had a lower body mass index (p<0.004) and higher systolic pressure (p<0.003). Participants with AR had larger aortic root diameters (3.6+/-0.4 vs. 3.4+/-0.4 cm, p<0.001), higher creatinine levels (1.3+/-1.3 vs. 1.0+/-1.0 mg/dl, p<0.001) and higher urine albumin/creatinine levels (3.6+/-2.3 vs. 3.3+/-2.0 log, p<0.001), as well as higher prevalences of aortic stenosis (AS) or mitral stenosis (MS) (p<0.001). Regression analysis showed that AR was independently related to older age and larger aortic roots (p<0.0001), AS and absence of diabetes (p = 0.002), MS (p = 0.003) and higher log urine albumin/creatinine (p = 0.005).

CONCLUSIONS

Aortic regurgitation occurred in 10% of a sample group of middle-aged to older adults and was related to older age, larger aortic root diameter, aortic and mitral stenosis and albuminuria. There was no association of AR with being overweight and a negative association of AR with diabetes.

Relation of generalized and central obesity to cardiovascular risk factors and prevalent coronary heart disease in a sample of American Indians: the Strong Heart Study

OBJECTIVE

To examine the hypothesis linking measures of obesity including body mass index (BMI), waist circumference (waist) and percentage body fat to coronary heart disease (CHD) prevalence and its risk factors in American Indians.

DESIGN

The Strong Heart Study assesses the prevalence of CHD and its risk factors in American Indians in Arizona, Oklahoma and South/North Dakota. Participants underwent a physical examination and an electrocardiogram; anthropometric and blood pressure measurements were taken, as were measurements of glucose, lipoproteins, fibrinogen, insulin, hemoglobin A1c and urinary albumin.

PARTICIPANTS

Data were available for 4549 men and women between 45 and 74 y of age.

MEASUREMENTS

Obesity, measured using body mass index, waist circumference and percentage body fat, was correlated with prevalent CHD and its risk factors.

RESULTS

More than 75% of participants were overweight (BMI>25 kg/m2). Measures of obesity were greater in women than in men, in younger than in older participants, and in participants with diabetes than in nondiabetic participants. CHD risk factors were associated with measures of obesity but, except for insulin concentration, changes in metabolic variables with increasing obesity were small. Associations were not stronger with waist than with BMI. The prevalence of CHD in those whose BMI and/or waist measurements lay in the lowest and highest quintiles, by gender and diabetic status, was similar.

CONCLUSIONS

Although CHD risk factors are associated with obesity in American Indians, distribution of obesity (ie waist) is no more closely related to risk factors than is generalized obesity (ie BMI), and changes in CHD risk factors with obesity were small. Thus, the relations among obesity, body fat distribution and CHD risk may differ in this population.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

LDL cholesterol as a strong predictor of coronary heart disease in diabetic individuals with insulin resistance and low LDL: The Strong Heart Study

Diabetes has been shown to increase the risk of coronary heart disease in all populations studied. However, there is a lack of information on the relative importance of diabetes-associated risk factors for cardiovascular disease (CVD), especially the role of lipid levels, because low density lipoprotein (LDL) cholesterol often is not elevated in diabetic individuals. The objective of this analysis was to evaluate CVD risk factors in a large cohort of diabetic individuals and to compare the importance of dyslipidemia (ie, elevated triglycerides and low levels of high density lipoprotein [HDL] cholesterol) and LDL cholesterol in determining CVD risk in diabetic individuals. The Strong Heart Study assesses coronary heart disease and its risk factors in American Indians in Arizona, Oklahoma, and South/North Dakota. The baseline clinical examinations (July 1989 to January 1992) consisted of a personal interview, physical examination, and drawing of blood samples for 4549 study participants (2034 with diabetes), 45 to 74 years of age. Follow-up averaged 4.8 years. Fatal and nonfatal CVD events were confirmed by standardized record review. Participants with diabetes, compared with those with normal glucose tolerance, had lower LDL cholesterol levels but significantly elevated triglyceride levels, lower HDL cholesterol levels, and smaller LDL particle size. Significant independent predictors of CVD in those with diabetes included age, albuminuria, LDL cholesterol, HDL cholesterol (inverse), fibrinogen, and percent body fat (inverse). A 10-mg/dL increase in LDL cholesterol was associated with a 12% increase in CVD risk. Thus, even at concentrations well below the National Cholesterol Education Program target of 130 mg/dL, LDL cholesterol is a strong independent predictor of coronary heart disease in individuals with diabetes, even when components of diabetic dyslipidemia are present. These results support recent recommendations for aggressive control of LDL cholesterol in diabetic individuals, with a target level of <100 mg/dL.

Prevalence of undiagnosed diabetes in three American Indian populations. A comparison of the 1997 American Diabetes Association diagnostic criteria and the 1985 World Health Organization diagnostic criteria: the Strong Heart Study

OBJECTIVE

In 1997, the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus of the American Diabetes Association (ADA) recommended three new sets of criteria for the diagnosis of diabetes that were different from those established by the World Health Organization (WHO) in 1985. One of these three methods was based on a fasting plasma glucose value only. This article compares ADA criteria with WHO criteria by applying them to three subgroups of American Indians in the Strong Heart Study who had no known diabetes.

RESEARCH DESIGN AND METHODS

The Strong Heart Study is a prospective epidemiological study of vascular disease in three American Indian populations aged 45-74 years. During the baseline examination from 1988 to 1991, participants without diagnosed diabetes underwent a fasting glucose test and a 2-h oral glucose tolerance test. These values were used to compare the ADA and WHO diagnostic criteria.

RESULTS

By using fasting and 2-h glucose values, prevalence rates of undiagnosed diabetes were 15.9% according to WHO criteria and 14.4% according to ADA criteria. The overall agreement rate was 65%, and the weighted kappa statistic was 0.474, which indicates moderate agreement. The age-specific analysis showed that, among participants between 45 and 54 years of age, the prevalence rates of undiagnosed diabetes were 13.4% according to WHO criteria and 12.7% according to ADA criteria. Among those aged 55-74 years, the rates were 18.7% according to WHO criteria and 16.3% according to ADA criteria. Thus, the difference in the prevalence rates when using WHO and ADA criteria, although generally small in this population, was three times higher in the older group (2.4%) than the difference in the younger group (0.7%).

CONCLUSIONS

The Strong Heart Study found that prevalence rates of undiagnosed diabetes determined by ADA criteria and WHO criteria were similar in its American Indian population. The data suggest that the difference between the two criteria may increase as age increases. Longitudinal data will be needed to evaluate further the utility of the two criteria.

Assessment of QT interval and QT dispersion for prediction of all-cause and cardiovascular mortality in American Indians: The Strong Heart Study

BACKGROUND

Both a prolonged QT interval and increased QT interval dispersion (QTD) have been proposed as surface ECG markers of vulnerability to ventricular arrhythmias and potential predictors of mortality.

METHODS AND RESULTS

The predictive values of QT prolongation and QTD were assessed in 1839 participants in the Strong Heart Study, a prospective study of cardiovascular disease in American Indians. ECGs were acquired at 250 Hz; QT intervals were measured by computer in all 12 leads and corrected for heart rate (QTc) by use of Bazett's formula. QTD was calculated as the difference between the maximum and minimum QTc. After a mean follow-up of 3.7+/-0.9 years, there were 188 deaths from all causes, including 55 cardiovascular deaths. In univariate Cox analyses, prolonged QTc and increased QTD were significant predictors of all-cause mortality (chi(2)=53.0, P<0.0001; chi(2)=11.3, P=0.0008) and cardiovascular mortality (chi(2)=14.7, P=0.0001; chi(2)=26.5, P<0.0001). In multivariate Cox regression analyses controlling for risk factors, QTc remained a strong predictor of all-cause mortality (chi(2)=16.5, P<0.0001) and a weaker predictor of cardiovascular mortality (chi(2)=5.8, P=0.016); QTD remained a significant predictor of cardiovascular mortality only (chi(2)=12.5, P=0.0004).

CONCLUSIONS

These findings support the value of computerized measurements of QTc and QTD in noninvasive risk stratification and suggest that these surface ECG variables may reflect different underlying abnormalities of ventricular repolarization.

Glycemic control in diabetic American Indians. Longitudinal data from the Strong Heart Study

OBJECTIVE

To describe glycemic control and identify correlates of elevated HbA1c levels in diabetic American Indians participating in the Strong Heart Study, which is a longitudinal study of cardiovascular disease in American Indians in Arizona, Oklahoma, South Dakota, and North Dakota.

RESEARCH DESIGN AND METHODS

This analysis is based on data from the baseline (1989-1992) and first follow-up (1994-1995) examinations of the Strong Heart Study. The 1,581 diabetic participants included in this analysis were aged 45-74 years at baseline, were diagnosed with diabetes before and at baseline, and had their HbA1c levels measured at follow-up. HbA1c was used as the index of glycemic control. Characteristics that may affect glycemic control were evaluated for cross-sectional and longitudinal relationships by analysis of covariance and multiple regression.

RESULTS

There was no significant difference between median HbA1c at baseline (8.4%) and at follow-up (8.5%). Sex, age (inversely), and insulin and oral hypoglycemic agent therapy were significantly related to HbA1c levels in both the cross-sectional and longitudinal analyses. Current smoking, prior use of alcohol, and duration of diabetes were significant only for the cross-sectional data. Baseline HbA1c significantly and positively predicted HbA1c levels at follow-up. Comparison of HbA1c by therapy type shows that insulin therapy produced a significant decrease in HbA1c between the baseline and follow-up examinations.

CONCLUSIONS

Glycemic control was poor among diabetic American Indians participating in the Strong Heart Study. Women, patients taking insulin or oral hypoglycemic agents, and younger individuals had the worst control of all the participants. Baseline HbA1c, and weight loss predicted worsening of control, whereas insulin therapy predicted improvement in control. Additional therapies and/or approaches are needed to improve glycemic control in this population.