A cardiovascular risk factor reduction clinic.

OBJECTIVE: To describe a cohort of patients referred to a cardiovascular risk factor reduction unit (CRFRU). DESIGN: Prospective cohort study. SETTING: Out-patients referred to a specialty clinic in a tertiary care hospital. PATIENTS: Seven hundred and four consecutive male and female patients with one or more cardiovascular risk factors, of whom 388 were reassessed after one year. INTERVENTIONS: Standard risk factors were measured in all participants. The probability of coronary artery disease (CAD) was assessed according to the Framingham equation and results were compared with data from the Saskatchewan Heart Health Survey for the general population of Saskatchewan. Patients received dietary and fitness advice, as well as drug therapy when indicated. For follow-up studies, the change in probability of CAD and selected variables after one year were measured. MAIN RESULTS: Patients referred to the CRFRU were at considerably higher risk for CAD than the general population. One hundred and sixty-eight of 235 men and 77 of 153 women seen in follow-up had a reduced risk score. Those who improved had a favourable change in systolic blood pressure and in their lipid profile, as well as greater weight loss. CONCLUSIONS: A CRFRU is feasible and appears to reduce risk in a considerable proportion of patients.

Sociodemographic variation in the prevalence of cardiovascular disease.

OBJECTIVE: To estimate the prevalence and social correlates of cardiovascular disease. DESIGN: Population-based cross-sectional survey. Survey data were obtained through a standardized home interview and a clinic visit by trained nurses. The question sequence of the London School of Hygiene (the Rose Questionnaire) was used to identify the presence of definite angina, possible infarction, definite infarction, intermittent claudication and stroke. SETTING: Eight urban communities and rural areas in Saskatchewan in 1990. PARTICIPANTS: A probability sample of 2167 noninstitutionalized men and women aged 18 to 74 years who participated in the Saskatchewan Heart Health Survey. MAIN OUTCOME MEASURES: Prevalence of cardiovascular diseases. RESULTS: Among men, the prevalence of definite angina increased gradually with age from 1.7% (95% CI 0.6% to 2.7%) in the 18 to 34 year group, 3.8% (1.3% to 6.0%) in the 35 to 54 year group to 4.8% (2.8% to 8.3%) in the 55 to 74 year group, while the prevalence among women ranged from 2.5% (1.2 to 3.7%), 4.0% (1.6% to 6.5%) to 7.1% (5.1% to 11.6%) in these same age groups. The prevalence of possible angina, definite infarction, possible infarction and intermittent claudication increased with age as well, being higher in men than in women. Generally, the conditions were more prevalent among those with less education, lower income and those who were unemployed. CONCLUSIONS: These findings indicate that there is sociodemographic inequality in the prevalence of these manifestations of cardiovascular disease, and there is a need for in-depth qualitative research into causal factors in this relationship and for targeted programs of health promotion.

Selective screening for dyslipidemia in a Canadian population.

The study assesses the clinical features of individuals that best enable an effective selective screening of the adult population for dyslipidemia. The results of the population-based 1990 Saskatchewan Heart Health Survey were examined. Dyslipidemia was defined as a total cholesterol (TC) to high-density lipoprotein cholesterol (HDL) ratio of > or = 5. In total, 805 men and 782 women, 18-74 years of age, had their plasma cholesterol measured. Using TC screening of the entire population as recommended by the Canadian Consensus Conference on Cholesterol would correctly identify 79% of those with dyslipidemia (sensitivity) and 67% of those with a normal profile (specificity). However, if one performs lipoprotein analysis on only those with a high waist-to-hip circumference ratio (WHR), 44% of the population would need to be screened to correctly identify 71% of those with dyslipidemia (sensitivity) and 66% of those with a normal profile (specificity). A high WHR is an especially strong predictor of dyslipidemia in young adults. In conclusion, a high WHR may provide an effective means of selective screening of the adult population for dyslipidemia.

Dyslipidemia and metabolic factors in the genesis of heart attack and stroke.

The relationship of dyslipidemia, particularly hypercholesterolemia to coronary heart disease is now well established. Although ischemic heart disease and stroke share many of the same risk factors, the relationship of cholesterol to stroke remains controversial. The 6-year and 12-year follow-up of the MRFIT study showed that elevated cholesterol significantly increased the risk for fatal nonhemorrhagic stroke. Atkins found no evidence that lowering plasma cholesterol influenced the incidence of fatal or nonfatal stroke and regression analysis showed no statistical association between the magnitude of cholesterol reduction and the risk for fatal stroke. We cannot preclude the possibility that more effective cholesterol lowering over a longer period of time might be effective. Hypertension is the most powerful risk factor for stroke. The San Antonio Heart Study reported a clustering of cardiovascular risk factors in individuals who developed hypertension during an eight-year follow-up period (higher levels of BP, fasting TC and LDLC, TG, glucose and insulin, and BMI, less favourable fat deposition, and lower HDL). Insulin resistance may be the unifying factor that results in those phenomena, the so-called syndrome X. The important factor underlying syndrome X may be central or visceral obesity, suggesting that maintenance or attainment of ideal weight would be a powerful preventive factor against both CHD and nonhemorrhagic stroke. There is evidence from the Treatment of Mild Hypertension Study that nutritional/hygienic measures can reduce the syndrome X risk factors and hence the risk of coronary heart disease and stroke.

Plasma lipids and lipoproteins and the prevalence of risk for coronary heart disease in Canadian adults. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To report population reference values for blood lipids, to determine the prevalence of lipid risk factors and to assess their association with other risk factors. DESIGN: Population-based cross-sectional surveys. Survey participants were interviewed at home and provided a blood sample at a clinic. All blood lipid analyses were done in the Lipid Research Laboratory, University of Toronto. The laboratory is standardized in the National Heart, Lung Blood Institute-Centres for Disease Control Standardization Program. SETTING: Nine Canadian provinces, from 1986 to 1990. PARTICIPANTS: A probability sample of 26,293 men and women aged 18 to 74 was selected from the health insurance registers for each province. Blood samples were obtained from 16,924 participants who had fasted 8 hours or more. OUTCOME MEASURES: Concentration of total plasma cholesterol, triglycerides and high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol in blood samples from fasting participants. MAIN RESULTS: Of the study population, 46% had total plasma cholesterol levels above 5.2 mmol/L, 15% had LDL-cholesterol levels above 4.1 mmol/L, 15% had triglyceride levels above 2.3 mmol/L and 8% had HDL-cholesterol levels below 0.9 mmol/L. Total plasma cholesterol, LDL-cholesterol and triglyceride levels rose with age in men to a maximum in the 45-54 age group; in women there was little change with age up to ages 45 to 54, at which time the level of each of these lipids increased appreciably. The age-standardized prevalence of obesity was positively associated with elevation of total plasma cholesterol. CONCLUSION: The results suggest the need for a multifactorial approach in health promotion efforts to lower blood cholesterol levels and reduce other risk factors in the population. A considerable number of adults were found to be at risk at all ages in both sexes. In the short term, men aged 34 and older and women aged 45 and older might benefit most from prevention programs.

Multiple cardiovascular disease risk factors in Canadian adults. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To estimate the prevalence and distribution of the coexistence of major cardiovascular disease (CVD) risk factors among Canadian adults. DESIGN: Population-based cross-sectional surveys. SETTING: Nine Canadian provinces, from 1986 to 1990. PARTICIPANTS: A probability sample of 26,293 men and women, aged 18 to 74 years, was selected from provincial health insurance registries. For 20,582 of these participants, at least two blood pressure (BP) measurements were taken using a standardized technique. At a subsequent visit to a clinic, two additional BP readings, anthropometric measurements and a blood specimen for plasma lipid analysis were obtained. OUTCOME MEASURES: The percentage distribution of subjects by number of major risk factors (smoking, high BP and elevated blood cholesterol level) and by concomitant factors (body mass index [BMI], ratio of waist to hip circumference [WHR], physical activity, diabetes, awareness of CVD risk factors and education). MAIN RESULTS: Sixty-four percent of men and 63% of women had one or more of the major risk factors. Prevalence increased with age to reach 80% in men and 89% in women aged 65 to 74 years. Prevalence of two or three risk factors was highest among men in the 45-54 age group (34%) and in women in the 65-74 age group (37%). The most common associations were between smoking and high blood cholesterol level (10%) and between high BP and high blood cholesterol level (8%). Prevalence of high BP and elevated blood cholesterol, alone or in combination, increased with BMI and WHR. Smoking, elevated blood cholesterol, BMI and prevalence of one or more risk factors increased with lower level of education. Less than 48% of participants mentioned any single major risk factor as a cause of heart disease. Awareness was lowest in the group with fewest years of education. CONCLUSION: The findings of this study call for an approach to reduce CVD that stresses collaboration of the different health sectors to reach both the population as a whole and the individuals at high risk.

Physician management of hyperlipidemia in Saskatchewan: temporal trends and the effect of a CME program.

OBJECTIVE: To assess current trends in the management of hyperlipidemia by Saskatchewan physicians, and to evaluate the effect of a specific continuing medical education (CME) program. DESIGN: Using a quasi-experimental design, physicians in an intervention area received the CME program while those in a comparison area did not. Management of hyperlipidemia was assessed before and after the program via a self-administered questionnaire. SETTING: All family physicians, general internists and cardiologists practising in the two areas were eligible. SUBJECTS: Of 439 eligible physicians, 308 (70%) completed the first survey, while 268 of 447 (60%) completed the second survey. Analysis was conducted on the 221 physicians who completed both surveys. INTERVENTION: Physicians in the intervention area received printed materials and attended a series of seminars between November 1988 and February 1989. Program content was based upon the recommendations of the Canadian Consensus Conference on Cholesterol (1988). MAIN RESULTS: Over the study period the mean level of serum cholesterol considered 'ideal' for a 40- to 60-year-old male decreased significantly from 5.43 to 5.03 mmol/L (P less than 0.001). The mean level at which diet therapy was begun decreased from 6.60 to 5.78 mmol/L (P less than 0.001) with a significantly greater proportion of physicians in the intervention area (58.0%) than in the comparison area (43.2%) initiating therapy in the 5.2 to 5.6 mmol/L range (P = 0.03). The mean level of serum cholesterol at which drug therapy is begun also decreased from 7.59 to 6.82 mmol/L (P less than 0.001), with a significantly greater proportion of physicians in the intervention (41.6%) than in the comparison area (25.0%) starting therapy in the 6.2 to 6.6 mmol/L range (P = 0.03). CONCLUSIONS: The management of hyperlipidemia reported by physicians in Saskatchewan changed dramatically between July 1988 and March 1989. The effect of the CME program is modest in comparison with this large temporal trend. The study provides further evidence that significant changes in the practice patterns of groups of physicians will only occur when the educational process is highly focused and personalized.

Toward the development of self-help health behaviour change programs: weight loss by correspondence.

The goal of this study was to evaluate a correspondence weight control program, and to assess the impact of three program elements (weekly homework, interim weigh-ins, and participation deposits) individually and in combination. All treated participants received 15 weekly standard lessons by mail. Three program features were varied factorially: a) homework assignments, b) interim weigh-ins and c) a deposit refunded contingent on returning homework and/or attending interim weigh-ins. Participants were assigned randomly to active treatment conditions or a delayed treatment control group. Among treated males (N = 14), initial average weight loss and BMI reduction were 9.6 kg and 3.1 respectively; average net weight loss and BMI reduction at one year follow-up were 5.8 kg and 1.9 respectively. Among treated females (N = 128), initial average weight loss and BMI reduction were 3.1 kg and 1.2 respectively; average net weight loss and BMI reduction at one year were 2.3 kg and .88 respectively. Women in all treated groups, except lessons only, showed a greater BMI reduction than untreated controls at the end of treatment. Women in conditions including both homework and interim weigh-ins had greater initial BMI reductions (M = 1.6) than those who received lessons only (M = .76). At one year, net BMI reductions were comparable across all treated groups. Of the 42 women initially registered in conditions that included both homework and weigh-ins, 12 who denied joining other programs lost at least 4.5 kg (M = 7.1) during treatment, and 7 had a net loss of at least 4.5 kg (M = 8.0) at one year without apparent involvement in any other program.

An unusual case of abdominal arteriovenous fistula.

Arteriovenous fistula between major abdominal vessels is an uncommon occurrence. It most frequently occurs between the aorta and the inferior vena cava; however, when occurring between the other arteries and veins, it is much rarer and has usually been secondary to surgical trauma or penetrating wounds. This is the report of an unusual case of an arteriovenous fistula, secondary to erosion of an atherosclerotic left iliac artery aneurysm into the left iliac vein.

The effects of education and group discussion in the post myocardial infarction patient.

An education and group discussion program administered to a randomly selected group of post myocardial infarction subjects failed to produce any differences in a large number of behavioral and psychological measures. These included smoking behavior, health status, social and recreational status, family and marital life and vocational activities, as well as measures of anxiety, depression, and health locus of control. Treated subjects were slower to return to work than controls and were less likely to have returned to work by the end of the study. More individuals in the treatment group were receiving compensation and this may have been a factor in delaying return to work. Since the majority of our subjects had a very optimistic attitude toward their eventual recovery, there was limited room for improvement. We suggest that cardiac rehabilitation be directed only at those patients with "negative" attitudes, and with more than usual anxiety and depression.

Evaluation of the echocardiogram as an epidemiologic tool in an asymptomatic population.

An asymptomatic adult population of 196 men and women was studied with the echocardiogram to derive age- and sex-specific "normal" values for a number of clinically used echocardiograhic variables. The results are in general agreement with previously published normal values. Body position during the examination, age and sex influence the echocardiographic results; body surface area correction normalized most of these effects. The prevalence of occult abnormalities determined by the echocardiogram is 7%; the most common finding was mitral valve prolapse. Inter- and intraobserver variability was assessed. The interobserver differences found on analysis are statistically, but not clinically , significant. The echocardiogram appears to be a suitable tool to use in epidemiologic studies to detect selected cardiac abnormalities, but is limited for this purpose because some subjects in such a population cannot be adequately examined.

Relaxation therapy for essential hypertension: a Veterans Administration Outpatient study.

Twenty-nine patients who had been treated with antihypertensive medication for at least the preceding 6 months were randomly assigned to (1) therapist-conducted, face-to-face progressive, deep-muscle relaxation training for 10 weekly sessions, or (2) progressive deep-muscle relaxation therapy conducted mainly by home use of audio cassettes, or (3) nonspecific individual psychotherapy for 10 weekly sessions. No differences between the groups were found immediately after therapy; however, the therapist-conducted relaxation therapy group showed the greatest changes: -17.8 mm Hg systolic, -9.7 mm Hg diastolic at 6 months follow-up. Some significant trends in results among the three therapists were also found. No correlation existed between blood pressure changes and changes in dopamine-beta-hydroxylase (DbH) levels.

Absorption of dietary beta-sitosterol in laying hens and its incorporation into the egg.

Studies were undertaken to determine the dietary beta-sitosterol absorption in laying hens and its incorporation into the egg. Hens were divided into four groups and fed a commercial low-fat laying diet. Group 1 served as controls; the diet of group 2 was supplemented with 10% corn oil; group 3 with 4% plant sterols (emulsion in carboxymethylcellulose); group 4 with 10% corn oil and 4% plant sterols. The daily beta-sitosterol intake of hens in groups 1, 2, 3 and 4 was 0.036 g 0.095 g, 2 g and 2.56 g, respectively. After consuming the diets for 30 to 40 days, cholesterol and beta-sitosterol contents of the eggs were estimated by gas liquid chromatographic and mass spectrometric methods. Feeding corn oil with and without plant sterols increased cholesterol content of the eggs, while feeding plant sterols alone had no effect on egg cholesterol levels. The beta-sitosterol content of eggs from groups 1 and 2 was similar (60-66 mug/g yolk) and feeding plant sterols increased the beta-sitosterol content to a very small extent (82-90 mug/g yolk). Studies on the dietary beta-sitosterol and cholesterol absorption indicated that there was very little absorption of beta-sitosterol. In control hens, beta-sitosterol absorption was about 7% compared to 81% cholesterol absorption. Plant sterols feeding did not affect the beta-sitosterol absorption but reduced cholesterol absorption by 40%. Feeding corn oil alone did not affect cholesterol absorption. Failure to detect any significant amount of beta-sitosterol in these hens. At the peak radioactivity deposition in the eggs, only 2% of the absorbed beta-sitosterol radioactivity was found in the eggs of group 4 compared to 5% found in group 1, while cholesterol radiioactivity was nearly 4 to 5 times in both groups. These data suggested that laying hens synthesized specific lipoproteins for deposition in yolk.

Effect of cholestyramine on tissue pools of cholesterol a preliminary report.

Four Type II Hyperlipoproteinemic subjects were investigated before and after treatment with cholestyramine. Plasma cholesterol was significantly reduced (365 plus or minus 23 vs 273 plus or minus 34 mg/100 ml) and triglycerides significantly increased (149 plus or minus 55 vs 181 plus or minus 59 mg/100 ml) on cholestyramine treatment. The daily turnover of cholesterol, as determined by the method of Goodman and Nobel, was nearly doubled by the treatment (0.813 plus or minus 0.11 vs 1.595 plus or minus 0.176 g). Although previous workers have already suggested that cholestyramine does not decrease tissue cholesterol pools, we observed a significant increase in tissue pools in each of the three subjects given cholestyramine alone (10.1 plus or minus 1.4 vs 16.2 plus or minus 6.9 g) for Pool A - EXCLUDING PLASMA; AND 27.2 PLUS OR MINUS 4.6 VS 43.7 PLUS OR MINUS 6.4 G FOR Pool B). Treatment for the fourth subject consisted of a combination of cholestyramine and clofibrate. This combination appeared to prevent increases in the size of Pool B and in the size and production rate of Pool A. These preliminary observations suggest that the hypocholesterolemic effect of cholestyramine may be enhanced and its effects on tissue cholesterol prevented by giving it in combination with other agents such as clofibrate.