Grethe S. Tell

Recruitment of adults 65 years and older as participants in the cardiovascular health study

Few large-scale epidemiologic studies have enrolled older adults; hence, little is known about the feasibility of recruiting this group for long-term population-based studies. In this article we present the recruitment experience of the Cardiovascular Health Study (CHS), a population-based, longitudinal study of cardiovascular diseases in adults 65 years and older. Participants were sampled from the Health Care Financing Administrations (HCFA) Medicare eligibility lists in four US communities. Letters were mailed to 11,955 sampled individuals. Persons recruited were required to complete an extensive home interview and then a 4-hour in-clinic examination. Excluded were persons who were expected to be able to complete the baseline examination and who were not expected to return for the 3-year follow-up. Some 3654 participants were recruited from those randomly selected from the Medicare sampling frame. In addition, 1547 other age-eligible persons living in the household with the sampled individuals also participated, yielding a total of 5201 participants. Of those who were contacted, 9.6% were ineligible and 34.9% refused participation. Among those eligible, 38.6% refused and 57.3% were enrolled (the remaining did not refuse but were not enrolled before the recruitment ended). Data from a subsample indicate that compared to those who were ineligible or who refused, enrolled participants were younger, more highly educated, more likely to be married, and less likely to report limitations in activity. Compared to those who were eligible but refused, enrolled participants were less likely to have high blood pressure and stroke and more likely to have quit smoking and to perceive their health status as very good or excellent.(ABSTRACT TRUNCATED AT 250 WORDS)

Subclinical Disease as an Independent Risk Factor for Cardiovascular Disease

BACKGROUND The primary aim of the present study was to determine the relation between measures of subclinical cardiovascular disease and the incidence of clinical cardiovascular disease among 5201 adults 65 years of age or older who were participating in the Cardiovascular Health Study. METHODS AND RESULTS A new method of classifying subclinical disease at baseline examination in the Cardiovascular Health Study included measures of ankle-brachial blood pressure, carotid artery stenosis and wall thickness, ECG and echocardiographic abnormalities, and positive response to the Rose Angina and Claudication Questionnaire. Participants were followed for an average of 2.39 years (maximum, 3 years). For participants without evidence of clinical cardiovascular disease at baseline, the presence of subclinical disease compared with no subclinical disease was associated with a significant increased risk of incident total coronary heart disease including CHD deaths and nonfatal MI and angina pectoris for both men and women. For individuals with subclinical disease, the increased risk of total coronary heart disease was 2.0 for men and 2.5 for women, and the increased risk of total mortality was 2.9 for men and 1.7 for women. The increased risk changed little after adjustment for other risk factors, including lipoprotein levels, blood pressure, smoking, and diabetes. CONCLUSIONS The measurement of subclinical disease provides an approach for identifying high-risk older individuals who may be candidates for more active intervention to prevent clinical disease.

Dietary Antioxidants and Carotid Artery Wall Thickness The ARIC Study

BACKGROUND Evidence that dietary antioxidants may prevent atherosclerotic disease is growing. The relationship between the intake of dietary and supplemental vitamin C, alpha-tocopherol, and provitamin A carotenoids and average carotid artery wall thickness was studied in 6318 female and 4989 male participants 45 to 64 years old int he Atherosclerosis Risk in Communities Study. METHODS AND RESULTS Intake was assessed by use of a 66-item semiquantitative food-frequency questionnaire. Carotid artery intima-media wall thickness was measured as an indicator of atherosclerosis at multiple sites with B-mode ultrasound. Among men and women > 55 years old who had not recently begun a special diet, there was a significant inverse relationship between vitamin C intake and average artery wall thickness adjusted for age, body mass index, fasting serum glucose, systolic and diastolic blood pressures, HDL and LDL cholesterol, total caloric intake, cigarette use, race, and education (test for linear trend across quintiles of intake, P = .019 for women and P = .035 for men). An inverse relationship was also seen between wall thickness and alpha-tocopherol intake but was significant only in women (test for linear trend, P = .033 for women and P = .13 for men). There was a significant inverse association between carotene intake and wall thickness in older men (test for linear trend, P = .015), but the association weakened after adjustment for potential confounders. No significant relationships were seen in participants < 55 years old. CONCLUSIONS These data provide limited support for the hypothesis that dietary vitamin C and alpha-tocopherol may protect against atherosclerotic disease, especially in individuals > 55 years old.

Physical fitness, physical activity, and cardiovascular disease risk factors in adolescents: the Oslo Youth Study.

Aerobic fitness, resting pulse rate, and self-reported physical activity were examined along with prevalence of cardiovascular disease risk factors in a population-based study of 413 boys and 372 girls, ages 10 to 14 years. Cardiovascular fitness (VO2 max) was predicted from heart rate measured during submaximal bicycle exercise. For both genders, fitness level was significantly and inversely related to body weight, body mass index [weight in kilos/(height in meters)2], triceps skinfold thickness, systolic and diastolic blood pressure, and pulse rate and positively related to high-density lipoprotein/total cholesterol ratio and physical activity. In addition, fitness level was positively related to high-density lipoprotein cholesterol and negatively related to triglycerides in females; it was also negatively related to height, total cholesterol, and hematocrit in males. Analyses of covariance, controlling for sexual maturity ratings, revealed that students in the lowest quartiles of VO2 max had significantly higher body mass index and triceps skinfold thickness than students in the higher quartiles. After adjustment for body mass index and sexual maturity ratings, blood pressure and pulse rate in both genders were significantly higher among students in the lower quartiles of VO2 max than among the groups who scored higher on the fitness test. Higher levels of VO2 max were also associated with a more favorable lipid profile in females. In gender-specific multiple regression analysis, triceps skinfold thickness was the strongest predictor of VO2 max, followed by pulse rate. Our study provides evidence that higher levels of fitness are associated with more favorable risk profiles in adolescents.

Relation between blood lipids, lipoproteins, and cerebrovascular atherosclerosis. A review.

Although blood lipids and lipoproteins are strongly related to coronary atherosclerosis, their association with cerebrovascular atherosclerosis is less clear. A review of more than 20 publications in which a relation was sought between plasma lipid and lipoprotein concentrations and cerebrovascular atherosclerosis leads to the general conclusion that such a relation exists and that it is stronger in older than in younger individuals. A relation was found between blood lipids and/or lipoproteins and the extent and/or severity of cerebrovascular atherosclerosis in all but three of 26 reviewed studies. However, the specific nature of the relation is obscure because the various studies cannot easily be compared with one another. Interstudy variations in lipoprotein fraction analyzed, methodology for the analysis of lipids and lipoproteins, arterial segment examined, population sampled, control selection in case-control studies, statistical analytic approach taken, and methodology for the assessment of arterial disease preclude pooled analyses. There is a clear need for further evaluation of this relation using standardized and up-to-date methodologies both for analyses of lipids and lipoproteins and for assessment of cerebrovascular disease in symptom-free volunteers as well as in symptomatic patients.

Relation of smoking with carotid artery wall thickness and stenosis in older adults. The Cardiovascular Health Study. The Cardiovascular Health Study (CHS) Collaborative Research Group.

BackgroundCigarette smoking has been associated with increased risk of atherosclerotic diseases in hospital–based studies and in studies of middle-aged populations but not in population-based studies of older adults with and without clinical cardiovascular disease. Methods and ResultsWe investigated the relation of smoking to carotid artery atherosclerotic disease, expressed as intimal-medial wall thickness and arterial lumen narrowing (stenosis) measured by ultrasound. Subjects were 5116 older adults participating in the baseline examination of the Cardiovascular Health Study, a community-based study of cardiovascular diseases in older age. With increased smoking there was significantly greater internal and common carotid wall thickening and internal carotid stenosis: current smokers > former smokers > never-smokers; for instance, the unadjusted percent stenosis was 24%, 20%, and 16%, respectively (P < .0001). A significant dose-response relation was seen with pack-years of smoking. These findings persisted after adjusting for other cardiovascular risk factors and were also confirmed when analyses were restricted to those without prevalent cardiovascular disease. The difference in internal carotid wall thickness between current smokers and nonsmokers was greater than the difference associated with 10 years of age among never-smoking participants (0.39 mm versus 0.31 mm). Among all participants, the prevalence of clinically significant (≥ 50%) internal carotid stenosis increased from 4.4% in never-smokers to 7.3% in former smokers to 9.5% in current smokers (P < .0001). ConclusionsThese findings extend previous reports of a positive relation between smoking and carotid artery disease to a population-based sample of older adults using several different indicators of atherosclerotic disease.

Risk factors for site specific extracranial carotid artery plaque distribution as measured by B-mode ultrasound☆

The effect of age, sex, diabetes, hypertension, pulse rate and cigarette smoking on extracranial carotid artery plaque thickness evaluated by B-mode ultrasonography was investigated in a cross-sectional study of 698 white men, 730 white women, 77 black men and 76 black women as part of a clinical ultrasound registry. Subjects were between 24 and 98 years of age, with a mean age of 63 years. Arterial locations evaluated were: proximal, mid and distal common carotid; the bifurcation; and the proximal and mid internal and external carotids. In a general linear multivariate analysis with plaque thickness at each site as the outcome variable, cigarette smoking and age were the two most consistent risk factors, and affected plaque thickness at all the investigated sites. Hypertension affected more sites than diabetes, men had more plaques than women, and except for the common carotid, whites had more plaques than blacks. Thus, risk factors were not uniformly associated with atherosclerosis at all sites of the extracranial carotid arteries.

Compensatory Increase in Common Carotid Artery Diameter: Relation to Blood Pressure and Artery Intima-Media Thickness in Older Adults

BACKGROUND AND PURPOSE Common carotid artery (CCA) diameter is thought to increase as a consequence of hypertension and may increase as the thickness of the arterial wall increases. The purpose of this study was to determine CCA dimensions and correlate them with clinical features. METHODS We performed a cross-sectional, community-based study of adults 65 years of age and older, measuring inner and outer diameter of the CCA in vivo with carotid sonography. Findings were correlated against risk factors for atherosclerosis, CCA intima-media thickness (IMT), and echocardiographically determined left ventricular (LV) mass. RESULTS Independent variables showing strong positive associations with outer and inner CCA diameter included age, male sex, height, weight, and systolic blood pressure. As an independent variable, LV mass (r = .40 and r = .37, respectively; P < .00001) had a strong positive relation to inner and outer CCA diameters. The relationship between diameter and IMT was different. In a model that controlled for age, sex, and estimated LV mass, an increase of 1 mm in CCA IMT corresponded to a 1.9 mm increase in the outer diameter of the artery (P < .00001) but was not significantly related to the inner diameter (slope = +0.07 mm; P = .26). CONCLUSIONS Increase in the outer diameter of the CCA is associated with subject size, sex, age, echocardiographically estimated LV mass, and CCA IMT. Increases in internal diameter of the CCA have similar relationships but are not related to IMT. This supports the hypothesis that the human CCA dilates as the thickness of the artery wall increases.

Survival of patients undergoing renal replacement therapy in one center with special emphasis on racial differences

This study compared racial differences in end-stage renal disease (ESRD) in 550 patients starting renal replacement therapy at a large academic dialysis center between January 1, 1990, and December 31, 1993, with follow-up through December 31, 1994. Patient groups were compared with respect to cause of ESRD, comorbid factors at the start of dialysis therapy, choice of modality, transplantation rate, and survival. Fifty-eight percent of the patients were white and 42% were African-American. There was a similar distribution of causes of ESRD between races. African-American patients were less likely to choose peritoneal dialysis as initial therapy (11.6% v 29.3%; P < 0.001) and were less likely to change dialysis modality. Transplantation rates were significantly different between African-American and white patients (9.3% v 27.6%; P < 0.001). African-Americans less frequently received living-related, living-nonrelated, and cadaveric renal transplants. Given differences in transplantation rates and in survival of transplanted patients versus patients on dialysis, survival analysis was performed without censoring for transplantation. A multivariate Cox proportional hazards model was formed, and the following were identified as being significant independent predictors of survival: age, race, age-race interaction, serum albumin at the start of dialysis, activity level at the start of dialysis, and presence of congestive heart failure and cancer. Age had little effect on survival among African-American patients, while it was a significant predictor of survival in white patients. In the group of patients starting dialysis before the age of 30 years, African-American patients had a significantly increased mortality risk compared with white patients. However, white patients older than 50 years had a higher mortality risk; this risk difference increased with age. Racial differences in mortality among older white patients could not be explained by differences in comorbid conditions, transplantation rates, or withdrawal from dialysis.

Current estrogen-progestin and estrogen replacement therapy in elderly women: Association with carotid atherosclerosis

The cardioprotective effects of combined estrogen/progestin replacement therapy have been questioned. Therefore, we have compared carotid arterial wall thickening and the prevalence of carotid stenosis in elderly women (> or = 65 years old) currently using replacement estrogen/progestins (E + P) with arterial pathology and its prevalence in women using unopposed estrogens (E). This cross-sectional study used baseline data from all 2962 women participating in the Cardiovascular Health Study, a population-based study of coronary heart disease and stroke in elderly adults. Users of hormone replacement therapy (HRT) were categorized as never (n = 1726), past (n = 787), current E (n = 280), or current E + P (n = 73). Maximal intimal-medial thicknesses of the internal and common carotid arteries and stenosis of the internal carotid arteries were measured by ultrasonography. Current E + P users resembled current E users in most respects, although some lifestyle factors were more favorable among E + P users. Current E + P use and current E use (as compared with no use) were associated with smaller internal carotid wall thicknesses (-0.22 mm; P = 0.003; and -0.09 mm; P = 0.05, respectively) and smaller common carotid wall thicknesses (-0.05 mm; P = 0.03; and -0.02 mm; P = 0.1, respectively) and lower odds ratios (OR) for carotid stenosis (> or = 1% vs. 0%); OR = 0.61; 95% confidence interval [CI]: 0.36 to 1.01; and OR = 0.91, 95% CI: 0.67 to 1.24, respectively), after adjustment for current lifestyle and risk factors. When both groups of current HRT users were compared, there were no significant differences in carotid wall thicknesses or prevalence of carotid stenosis. For this sample of elderly women, both current E + P therapy and current E therapy were associated with decreased measures of carotid atherosclerosis. These measures did not differ significantly between the two groups of HRT users.