Cardiovascular effects of intensive lifestyle intervention in type 2 diabetes.

BACKGROUND: Weight loss is recommended for overweight or obese patients with type 2 diabetes on the basis of short-term studies, but long-term effects on cardiovascular disease remain unknown. We examined whether an intensive lifestyle intervention for weight loss would decrease cardiovascular morbidity and mortality among such patients. METHODS: In 16 study centers in the United States, we randomly assigned 5145 overweight or obese patients with type 2 diabetes to participate in an intensive lifestyle intervention that promoted weight loss through decreased caloric intake and increased physical activity (intervention group) or to receive diabetes support and education (control group). The primary outcome was a composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for angina during a maximum follow-up of 13.5 years. RESULTS: The trial was stopped early on the basis of a futility analysis when the median follow-up was 9.6 years. Weight loss was greater in the intervention group than in the control group throughout the study (8.6% vs. 0.7% at 1 year; 6.0% vs. 3.5% at study end). The intensive lifestyle intervention also produced greater reductions in glycated hemoglobin and greater initial improvements in fitness and all cardiovascular risk factors, except for low-density-lipoprotein cholesterol levels. The primary outcome occurred in 403 patients in the intervention group and in 418 in the control group (1.83 and 1.92 events per 100 person-years, respectively; hazard ratio in the intervention group, 0.95; 95% confidence interval, 0.83 to 1.09; P=0.51). CONCLUSIONS: An intensive lifestyle intervention focusing on weight loss did not reduce the rate of cardiovascular events in overweight or obese adults with type 2 diabetes. (Funded by the National Institutes of Health and others; Look AHEAD ClinicalTrials.gov number, NCT00017953.).

P wave indices, obesity, and the metabolic syndrome: the atherosclerosis risk in communities study.

Atrial fibrillation and obesity are increasing in prevalence and are interrelated epidemics. There has been limited assessment of how obesity and the metabolic syndrome impact P wave indices, established electrocardiographic predictors of atrial fibrillation. We conducted a cross-sectional analysis to determine the association of obesity and the components of the metabolic syndrome with P wave indices in the population-based Atherosclerosis Risk in Communities (ARIC) study. Analyses were adjusted for demographic, anthropometric and clinical variables, and cardiovascular diseases and risk factors. Following relevant exclusions, 14,433 subjects were included (55% women and 24.7% black). In multivariable analyses, we identified significant, progressive increases in PR interval, P wave maximum duration, and P wave terminal force with BMI 25-30 kg/m(2) and BMI ≥30 kg/m(2) compared to the reference group <25 kg/m(2) (P < 0.0001 for trend for all P wave indices). These effects were present in both blacks and whites. Presence of metabolic syndrome was also associated with longer P wave indices. When components of the metabolic syndrome were examined separately, hypertension resulted in significant (P < 0.001) augmentation of the three P wave indices. Similarly, waist circumference was associated with greater P wave maximum duration in both races (P < 0.001). We concluded that P wave indices are significantly associated with obesity and particularly with hypertension and waist circumference. P wave indices may comprise intermediate markers, independent of age and cardiovascular risk, of the pathway linking obesity and with the risk of atrial fibrillation (AF).

Long-term prognosis associated with J-point elevation in a large middle-aged biracial cohort: the ARIC study.

AIMS: An association has been described between death from arrhythmia and early repolarization, an electrocardiogram pattern characterized by elevation of the QRS-ST junction (J-point). Little is known about this relationship in non-white populations. This study examines the relationship between J-point elevation (JPE) and sudden cardiac death (SCD) and whether this relationship differs by race or sex. METHODS AND RESULTS: A total of 15 141 middle-aged subjects from the prospective, population-based Atherosclerosis Risk in Communities (ARIC) study were included in this analysis. The primary endpoint was physician-adjudicated SCD occurring from baseline (1987-1989) through December 2002, secondary endpoints were fatal and non-fatal coronary events and all-cause mortality occurring through December 2007. J-point elevation was defined as J-point amplitude ≥ 0.1 mV. Pre-specified subgroup analyses by sex and race were conducted. J-point elevation in any lead was present in 1866 subjects (12.3%). After adjustment for demographic, clinical, lifestyle, and laboratory variables, JPE was not significantly related to SCD in the overall sample [adjusted hazard ratio (HR), 1.23; 95% confidence interval (CI), 0.87-1.75]. However, significant interactions were present between race and JPE (P = 0.006) and between sex and JPE (P = 0.020). J-point elevation was significantly predictive of SCD in whites (adjusted HR, 2.03; 95% CI, 1.28-3.21) and in females (adjusted HR, 2.54; 95% CI, 1.34-4.82). CONCLUSION: Our results suggest that JPE is associated with an increased risk of SCD in whites and in females, but not in blacks or males. Further studies are needed to clarify which subgroups of individuals with JPE are at increased risk for adverse cardiac events.

Longitudinal examination of age-predicted symptom-limited exercise maximum HR.

PURPOSE: To estimate the association of age with maximal HR (MHR). METHODS: Data were obtained from the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants were black and white men and women aged 18-30 yr in 1985-1986 (year 0). A symptom-limited maximal graded exercise test was completed at years 0, 7, and 20 by 4969, 2583, and 2870 participants, respectively. After exclusion, 9622 eligible tests remained. RESULTS: In all 9622 tests, estimated MHR (eMHR, bpm) had a quadratic relation to age in the age range of 18-50 yr, eMHR = 179 + 0.29 x age - 0.011 x age(2). The age-MHR association was approximately linear in the restricted age ranges of consecutive tests. In 2215 people who completed tests of both years 0 and 7 (age range = 18-37 yr), eMHR = 189 - 0.35 x age; and in 1574 people who completed tests of both years 7 and 20 (age range = 25-50 yr), eMHR = 199 - 0.63 x age. In the lowest baseline body mass index (BMI) quartile, the rate of decline was 0.24 bpm*yr(-1) between years 0 and 7 and 0.51 bpm*yr(-1) between years 7 and 20, whereas in the highest baseline BMI quartile, there was a linear rate of decline of approximately 0.7 bpm.yr for the full age range of 18-50 yr. CONCLUSIONS: Clinicians making exercise prescriptions should be aware that the loss of symptom-limited MHR is much slower in young adulthood and more pronounced in later adulthood. In particular, MHR loss is very slow in those with the lowest BMI younger than 40 yr.

Atrial fibrillation at baseline and during follow-up in ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial).

OBJECTIVES: The ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) determined that treatment with amlodipine, lisinopril, or doxazosin was not superior to thiazide-like diuretic (chlorthalidone) in preventing coronary heart disease (CHD) or other cardiovascular events. This subanalysis examines baseline prevalence and in-trial incidence of new-onset atrial fibrillation (AF) or atrial flutter (AFL) and their influence on clinical outcomes. BACKGROUND: Limited information is available on whether atrial fibrillation incidence is affected differentially by different classes of antihypertensive medications or treatment with statins. METHODS: AF/AFL was identified from baseline and follow-up electrocardiograms performed biannually. Analyses were performed to identify characteristics associated with baseline AF/AFL and its subsequent incidence. RESULTS: AF/AFL was present at baseline in 423 participants (1.1%), more frequent in men (odds ratio: 1.72; 95% confidence interval [CI]: 1.37 to 2.17) and nonblacks (odds ratio: 2.09; 95% CI: 1.58 to 2.75). Its prevalence increased with age (p < 0.001) and was associated with CHD, cardiovascular disease, obesity, and high-density lipoprotein cholesterol <35 mg/dl. New-onset AF/AFL was associated with the same baseline risk factors plus electrocardiogram left ventricular hypertrophy. It occurred in 641 participants (2.0%) and, excluding doxazosin, did not differ by antihypertensive treatment group or, in a subset of participants, by pravastatin versus usual care. Baseline AF/AFL was associated with increased mortality (hazard ratio [HR]: 2.82; 95% CI: 2.36 to 3.37; p < 0.001), stroke (HR: 3.63; 95% CI: 2.72 to 4.86; p < 0.001), heart failure (HR: 3.17; 95% CI: 2.38 to 4.25; p < 0.001), and fatal CHD or nonfatal myocardial infarction (HR: 1.64; 95% CI: 1.22 to 2.21; p < 0.01). There was a nearly 2.5-fold increase in mortality risk when AF/AFL was present at baseline or developed during the trial (HR: 2.42; 95% CI: 2.11 to 2.77; p < 0.001). CONCLUSIONS: In this high-risk hypertensive population, pre-existing and new-onset AF/AFL were associated with increased mortality. Excluding doxazosin, treatment assignment to either antihypertensive drugs or pravastatin versus usual care did not affect AF/AFL incidence. (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial [ALLHAT]; NCT00000542).

Clinical correlates and heritability of QT interval duration in blacks: the Jackson Heart Study.

BACKGROUND: Electrocardiographic QT interval prolongation is a risk factor for sudden cardiac death and drug-induced arrhythmia. The clinical correlates and heritability of QT interval duration in blacks have not been well studied despite their higher risk for sudden cardiac death compared with non-Hispanic whites. We sought to investigate potential correlates of the QT interval and estimate its heritability in the Jackson Heart Study. METHODS AND RESULTS: The Jackson Heart Study comprises a sample of blacks residing in Jackson, Miss, of whom 5302 individuals with data at the baseline examination were available for study. Jackson Heart Study participants on QT-altering medications, with bundle-branch block, paced rhythm, atrial fibrillation/flutter, or other arrhythmias were excluded, resulting in a sample of 4660 individuals eligible for analyses. The relation between QT and potential covariates was tested using multivariable stepwise linear regression. Heritability was estimated using Sequential Oligogenic Linkage Analysis Routine in a subset of 1297 Jackson Heart Study participants in 292 families; the remaining sample included unrelated individuals. In stepwise multivariable linear regression analysis, covariates significantly associated with QT interval duration included R-R interval, sex, QRS duration, age, serum potassium, hypertension, body mass index, coronary heart disease, diuretic use, and Sokolow-Lyon voltage (P < or = 0.01 for all). The heritability of QT interval duration in the age-, sex-, and R-R interval-adjusted model and in the fully adjusted model was 0.41 (SE, 0.07) and 0.40 (SE, 0.07; P < 10(-11) for both), respectively. CONCLUSIONS: There is substantial heritability of adjusted QT interval in blacks, supporting the need for further investigation to identify its genetic determinants.

Relation of heart rate parameters during exercise test to sudden death and all-cause mortality in asymptomatic men.

Heart rate (HR) profile during exercise predicts all-cause mortality. However, less is known about its relation to sudden (vs nonsudden) death in asymptomatic people. The relation of exercise HR parameters (HR at rest, target HR achievement, HR increase, and HR recovery) with sudden death, coronary heart disease (CHD) death, myocardial infarction, and all-cause mortality was assessed in 12,555 men who participated in MRFIT. Subjects were 35 to 57 years old without clinical CHD, but with higher than average Framingham risk. Trial follow-up was 7 years, and extended follow-up after the trial for all-cause mortality was 25 years. After adjusting for cardiac risk factors, having to stop exercise before achieving 85% of age-specific maximal HR was associated with increased risk of sudden death (hazard ratio 1.8, 95% confidence interval [CI] 1.3 to 2.5, p = 0.001), CHD death (hazard ratio 1.4, 95% CI 1.2 to 1.5, p <0.001), and all-cause mortality (hazard ratio 1.3, 95% CI 1.2 to 1.4, p <0.001). Increased HR at rest (p = 0.001), attenuated HR increase (p = 0.02), delayed HR recovery (p = 0.04), and exercise duration (p <0.0001) were independent predictors of all-cause death in the overall study population and also in the subgroup that achieved target HR. In conclusion, middle-aged men without clinical CHD who stopped exercise before reaching 85% of maximal HR had a higher risk of sudden death. Other exercise HR parameters and exercise duration predicted all-cause mortality.

Comparison of electrocardiographic findings and associated risk factors between Taiwan Chinese and US White adults.

BACKGROUND: Electrocardiographic (ECG) findings are known to differ by race, however, systematic comparisons of findings between eastern and western countries are rare. OBJECTIVE: To compare the ECG findings and associated coronary heart disease (CHD) risk factors between Taiwan Chinese and US White adults aged >or=40 years. METHODS: We compared the prevalence rate of Minnesota Code criteria based ECG findings and associated CHD risk factors by using data from the third National Health and Nutrition Examination Survey (NHANES III) and the Nutrition and Health Survey in Taiwan (NAHSIT, 1993-1996). RESULTS: Examining all the ECG findings collectively, we observed a higher prevalence of major Minnesota Code findings in Taiwan Chinese women than in US White women (15.0% vs. 10.5%), particularly ST segment depression (5.4% vs. 2.4%) and T wave abnormalities (10.8% vs. 4.8%). The prevalence of major Minnesota Code findings was similar in both Taiwan Chinese and US White men (22.7% vs. 19.6%). Taiwan Chinese men had a higher prevalence of ST segment elevation (13.7% vs. 0.9%). Taiwan Chinese also had a higher prevalence of left ventricular hypertrophy with repolarization change than US Whites in both sexes (2.7% vs. 1.4% for men, 4.3% vs. 1.3% for women). Taiwan Chinese had more favorable CHD risk factor profiles than US Whites, including lipid profile, obesity, central obesity, and smoking status. The prevalence of hypertension was similar between the two groups, however, a lower percentage of Taiwan Chinese received treatment. Taiwan Chinese men had a lower prevalence of diabetes mellitus than US White men, whereas Taiwan Chinese women had a higher prevalence than US White women. CONCLUSION: These results suggest that substantial differences in ECG findings exist between Taiwan Chinese and US Whites which cannot be entirely explained by CHD risk factors alone.

Exercise capacity and cardiovascular/metabolic characteristics of overweight and obese individuals with type 2 diabetes: the Look AHEAD clinical trial.

OBJECTIVE: We examined associations of cardiovascular, metabolic, and body composition measures with exercise capacity using baseline data from 5,145 overweight and/or obese (BMI > or = 25.0 kg/m2) men and women with type 2 diabetes who were randomized participants for the Look AHEAD (Action for Health in Diabetes) clinical trial. RESEARCH DESIGN AND METHODS: Peak exercise capacity expressed as METs and estimated from treadmill speed and grade was measured during a graded exercise test designed to elicit a maximal effort. Other measures included waist circumference, BMI, type 2 diabetes duration, types of medication used, A1C, history of cardiovascular disease, metabolic syndrome, beta-blocker use, and race/ethnicity. RESULTS: Peak exercise capacity was higher for men (8.0 +/- 2.1 METs) than for women (6.7 +/- 1.7 METs) (P < 0.001). Exercise capacity also decreased across each decade of age (P < 0.001) and with increasing BMI and waist circumference levels in both sexes. Older age, increased waist circumference and BMI, a longer duration of diabetes, increased A1C, a history of cardiovascular disease, having metabolic syndrome, beta-blocker use, and being African American compared with being Caucasian were associated with a lower peak exercise capacity for both sexes. Hypertension and use of diabetes medications were associated with lower peak exercise capacity in women. CONCLUSIONS: Individuals with diabetes who are overweight or obese have impaired exercise capacity, which is primarily related to age, female sex, and race, as well as poor metabolic control, BMI, and central obesity.

The effect of intensive diabetes treatment on resting heart rate in type 1 diabetes: the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study.

OBJECTIVE: Cardiovascular disease is a major cause of morbidity and mortality in individuals with type 1 diabetes. Resting heart rate (RHR) is a risk factor for cardiovascular disease in the general population, and case-control studies have reported a higher RHR in individuals with type 1 diabetes. In individuals with type 1 diabetes, there is a positive correlation between A1C and RHR; however, no prospective studies have examined whether a causal relationship exists between A1C and RHR. We hypothesized that intensive diabetes treatment aimed to achieve normal A1C levels has an effect on RHR in individuals with type 1 diabetes. RESEARCH DESIGN AND METHODS: A total of 1,441 individuals with type 1 diabetes who participated in the Diabetes Control and Complications Trial (DCCT) had their RHR measured biennially by an electrocardiogram during the DCCT and annually for 10 years during the Epidemiology of Diabetes Interventions and Complications (EDIC) follow-up study. RESULTS: During the DCCT, intensive treatment was associated with lower mean RHR than conventional treatment, both in adolescents (69.0 vs. 72.0 bpm [95% CI 62.8-75.7 and 65.7-78.9, respectively], P = 0.013) and adults (66.8 vs. 68.2 [65.3-68.4 and 66.6-69.8, respectively], P = 0.0014). During follow-up in the EDIC, the difference in RHR between the treatment groups persisted for at least 10 years (P < 0.0001). CONCLUSIONS: Compared with conventional therapy, intensive diabetes management is associated with lower RHR in type 1 diabetes. The lower RHR with intensive therapy may explain, in part, its effect in reducing cardiovascular disease, recently demonstrated in type 1 diabetes.

Subclinical cardiovascular disease markers applicable to studies of oral health: multiethnic study of atherosclerosis.

Recent findings associate periodontal disease with established coronary heart disease (CHD) and with disorders of the carotid artery. Besides measures of the carotid artery, a number of other noninvasive subclinical markers of cardiovascular disease exist and are summarized here. Included are computed tomography (CT) of the coronary arteries, ultrasound of the carotid arteries, echocardiography, magnetic resonance imaging (MRI), ankle-brachial index, microalbuminuria, and other biochemical measures of kidney dysfunction, flow-mediated dilation in the brachial artery, and pulse wave form analysis. Use of these measures may simplify and add depth to studies of oral health and cardiovascular disease. However, it is noted that the measures are not highly correlated with each other (based on 6,814 persons in the Multiethnic Study of Atherosclerosis, Pearson correlations among the above subclinical measures, range from about 0.1-0.4), do not include propensity for the important atherosclerotic phase of plaque rupture, and do not fully substitute for studies of clinical cardiovascular disease endpoints.

Electrocardiographic findings and incident coronary heart disease among participants in the Atherosclerosis Risk in Communities (ARIC) study.

The associations of many electrocardiographic (ECG) abnormalities at rest with incident coronary heart disease (CHD) are not completely established, and whether individual ECG abnormalities convey similar risk across gender and race is uncertain. We studied the independent association of several ECG findings with incident CHD, testing for effect modification by gender and race, in a large, population-based, prospective cohort study. Findings from the baseline 12-lead electrocardiograms in 1987 to 1989 were classified according to the Minnesota Code in 12,987 black and white men and women, aged 45 to 64 years, who were initially free of CHD and the use of specific cardiac medications. The incidence of CHD was ascertained through 2000. After adjustment for multiple cardiovascular risk factors, the ECG findings that had the highest hazard rate ratios (HRRs) for incident CHD, when considered singly, were left ventricular hypertrophy with ST-T strain pattern in white men (HRR 6.50) and in black women (HRR 2.31) and, in the whole cohort, major (HRR 2.27) and minor (HRR 2.47) ST depression and major T-wave abnormalities (HRR 2.12). Statistically significant associations were also found in the whole cohort for minor Q waves and left ventricular hypertrophy by the Cornell definition, but not for a prolonged QTc interval, major ventricular conduction defects, or ST elevation. In conclusion, several 12-lead ECG findings were independently associated with incident CHD in middle-aged adults. With only a few exceptions, the associations were similar for blacks and whites.

Eliminating diagnostic drift in the validation of acute in-hospital myocardial infarction--implication for documenting trends across 25 years: the Minnesota Heart Survey.

Long-term trends in epidemiologic studies of acute myocardial infarction (AMI) require application of a consistent diagnostic algorithm. Typically an algorithm includes chest pain, cardiac enzymes, electrocardiographic findings, and autopsy results. The Minnesota Heart Survey (MHS) has determined trends for incident AMI and for in-hospital and long-term outcomes over a 25-year period (1970-1995). However, dramatic changes have occurred that seriously challenge the ability of the MHS and other epidemiologic studies to use a consistent diagnostic algorithm. These include newer and more sensitive cardiac biomarkers, introduction of diagnosis-related groups, and change in International Classification of Diseases coding. In the MHS, the electrocardiogram is the only diagnostic element consistently available and consistently classified over this 25-year period. The authors identified eight dichotomous Minnesota Code criteria that provided a consistent diagnostic method from 1970 to 1995 as documented by extensive cross-validation. These criteria were combined into a logistic score and used to define incident, recurrent, and attack AMI rates over this 25-year period. For both men and women, AMI rates determined by electrocardiogram are parallel to rates based on the International Classification of Diseases and parallel over adjacent survey periods to the standard MHS algorithm. The electrocardiogram classified by Minnesota Code provides the only consistent long-term diagnostic tool for AMI trends over this 25-year period.

The association of spatial T wave axis deviation with incident coronary events. The ARIC cohort.

BACKGROUND: Although current evidence suggests that the spatial T wave axis captures important information about ventricular repolarization abnormalities, there are only a few and discordant epidemiologic studies addressing the ability of the spatial T wave axis to predict coronary heart disease (CHD) occurrence. METHODS: This prospective study analyzed data from 12,256 middle-aged African American and white men and women, from the Atherosclerosis Risk in Communities Study (ARIC). Following a standardized protocol, resting standard 12-lead, 10-second electrocardiograms were digitized and analyzed with the Marquette GE program. The median follow-up time was 12.1 years; incident coronary heart disease comprised fatal and non-fatal CHD events. RESULTS: The incidence rate of CHD was 4.26, 4.18, 4.28 and 5.62 per 1000 person-years respectively, across the spatial T wave axis quartiles. Among women for every 10 degrees increase in the spatial T wave axis deviation, there was an estimated increase in the risk of CHD of 1.16 (95% CI 1.04-1.28). After adjustment for age, height, weight, smoking, hypertension, diabetes, QRS axis and minor T wave abnormalities, this hazard rate ratio for women fell to 1.03 (0.92-1.14). The corresponding crude and adjusted hazard ratios for men were 1.05 (95% CI 0.96-1.15) and 0.95 (0.86-1.04) respectively. CONCLUSIONS: In conclusion, this prospective, population-based, bi-ethnic study of men and women free of coronary heart disease at baseline shows that spatial T wave axis deviation is not associated with incident coronary events during long-term follow up. It is doubtful that spatial T wave axis deviation would add benefit in the prediction of CHD events above and beyond the current traditional risk factors.

Heart rate-corrected QT interval prolongation predicts risk of coronary heart disease in black and white middle-aged men and women: the ARIC study.

OBJECTIVES: We aimed to study the predictive value of heart rate-corrected QT interval (QTc) for incident coronary heart disease (CHD) and cardiovascular disease (CVD) mortality in the black and white general population, and to validate various QT measurements. BACKGROUND: QTc prolongation is associated with higher risk of mortality in cardiac patients and in the general population. Little is known about the association with incident CHD. No previous studies included black populations. METHODS: We studied the predictive value of QTc prolongation in a prospective population study of 14,548 black and white men and women, age 45 to 64 year. QT was determined by the NOVACODE program in the digital electrocardiogram recorded at baseline. RESULTS: In quintiles of QTc, cardiovascular risk profile deteriorated with longer QTc, and risk of CHD and CVD mortality increased. The high risk in the upper quintile was mostly explained by the 10% with the longest QTc. The age-, gender-, and race-adjusted hazard ratios for CVD mortality and CHD in subjects with the longest 10% relative to the other 90% of the gender-specific QTc distribution were 5.13 (95% confidence interval 3.80 to 6.94) and 2.14 (95% confidence interval 1.71 to 2.69), respectively. The increased risk was partly, but not completely, attributable to other risk factors or the presence of chronic disease. The association was stronger in black than in white subjects. Manual- and machine-coded QT intervals were highly correlated, and the method of rate correction did not affect the observed associations. CONCLUSIONS: Long QTc is associated with increased risk of CHD and CVD mortality in black and white healthy men and women.

Prognostic significance of corrected QT and corrected JT interval for incident coronary heart disease in a general population sample stratified by presence or absence of wide QRS complex: the ARIC Study with 13 years of follow-up.

BACKGROUND: Heart rate-corrected QT interval (QTc) is the traditional method of assessing the duration of repolarization. Prolonged heart rate-corrected QT interval is associated with higher risk of mortality in patients with coronary heart disease (CHD) and in the general population. However, the QTc is typically not evaluated when QRS duration is > or =120 ms, because increased QRS duration (QRSd) contributes to QT interval prolongation. In these circumstances, the JT interval has been proposed as a more valid way to assess ventricular repolarization. METHODS AND RESULTS: To allow for variation in heart rate, corrected JT interval (JTc) was defined as QTc-QRSd. Using data from the Atherosclerosis Risk in Communities Study, JTc and QTc were compared for their prognostic associations with incident CHD events among 14 696 men and women who were CHD-free at baseline, having either normal conduction or wide QRS complex. Among individuals with normal QRS duration, logistic regression adjusted for age, hypertensive status, diabetes, race, systolic blood pressure, smoking, HDL and LDL cholesterol, R-R interval, and menopausal status in women showed QTc and JTc were nonpredictive of future coronary events in men but significant in women. In individuals with wide QRS complex (QRSd > or =120 ms), similar analyses showed JTc had a significant prognostic advantage compared with QTc in men but not in women, among whom only 11 events occurred. CONCLUSIONS: The JTc is a simple measurement that is a significant independent predictor of incident CHD events in men with wide QRS complex.

Early life factors contribute to the decrease in lung function between ages 18 and 40: the Coronary Artery Risk Development in Young Adults study.

Early life factors may influence pulmonary function. We measured forced expiratory volume in 1 second (FEV(1)) in 1985-1986 and 2, 5, and 10 years later in approximately 4,000 black and white men and women initially aged 18-30 years. We estimated the age pattern of FEV(1) according to family smoking status, early diagnosis of asthma, early smoking initiation, adult asthma, and cigarette smoking. FEV(1) followed a quadratic pattern from age of peak through age 40. The pattern varied by race and sex. Early smoking initiation was associated with a faster decrease in FEV(1). Smoking by family members was related to early life asthma and may have contributed to faster FEV(1) decrease by encouraging behaviors such as heavier smoking or earlier smoking initiation. Prevalence of smoking was 28% when no family member smoked, compared with 59% when four or more members smoked. The FEV(1) decline was 8.5% in never-smokers without asthma; 10.1% in nonsmoking individuals diagnosed with asthma; and 11.1% in baseline smokers who smoked 15 or more cigarettes per day. The combination of asthma and heavier smoking was synergistic (17.8% decline). This study delineates an increased rate of decline in those with asthma or in those who smoke cigarettes and implicates early life exposures as contributing to the faster rate of FEV(1) decline.

Prevalence of premature ventricular contractions in a population of African American and white men and women: the Atherosclerosis Risk in Communities (ARIC) study.

BACKGROUND: The distribution or the causes of premature ventricular contractions (PVCs) in diverse populations are not fully known. We describe the prevalence of PVCs on a 2-minute electrocardiogram (ECG) in adults to determine whether hypertension has an important association with such PVCs. METHODS: A cross-sectional analysis of the 15,792 individuals (aged 45-65 years) from the four US communities participating at visit 1 of the Atherosclerosis Risk In Communities (ARIC) study was performed. Multiple logistic regression was used to determine the association of PVCs with potential causal predictors of PVCs. RESULTS: Based on a 2-minute ECG, PVCs are present in >6% of middle-aged adults. Increasing age, the presence of heart disease, faster sinus rates, African American ethnicity, male sex, lower educational attainment, and lower serum magnesium or potassium levels are directly related to PVC prevalence. Independently of these factors, hypertension is associated with a 23% increase in the prevalence of PVCs. CONCLUSIONS: The prevalence of PVCs on a 2-minute ECG differs by age, ethnicity, and sex and is associated with hypertension, heart disease, faster sinus rates, electrolyte abnormalities, and lower educational attainment. Hypertension is likely to be a major cause of PVCs in adults.