Fish consumption and cardiovascular disease in the physicians' health study: a prospective study

The authors examined the association between dietary intake of fish and omega 3 fatty acids from seafood and the risk of cardiovascular disease in a prospective cohort study of 21,185 US male physicians who are participants in the Physicians' Health Study. In 4 years of follow-up, there were 281 incident cases of total (fatal and nonfatal) myocardial infarction, 173 cases of stroke, and 121 cardiovascular deaths. There was no evidence for association between dietary intake of fish and any cardiovascular endpoint, including myocardial infarction, stroke, and cardiovascular death. The relative risks of total myocardial infarction, adjusted for age and randomized treatment assignment, for categories of fish intake were: 1.0 for < 1 meal/week (referent), 1.6 (95% confidence interval (Cl) 1.1-2.3) for 1 fish meal/week; 1.4 (95% Cl 1.0-2.0) for 2-4 fish meals/week; and 1.2 (95% Cl 0.6-2.2) for > or = 5 fish meals/week; chi 2 for trend = 0.9, p = 0.34. The relative risks were similar for omega 3 fatty acid intake and for specific types of fish, and did not change after adjustment for history of hypertension, hypercholesterolemia, diabetes mellitus, or angina pectoris, parental history of myocardial infarction before age 60 years, obesity, exercise, smoking, alcohol use, saturated fat intake, and vitamin supplement use. These data do not support the hypothesis that moderate fish consumption lowers the risk of cardiovascular disease.

A secondary prevention trial of antioxidant vitamins and cardiovascular disease in women. Rationale, design, and methods. The WACS Research Group

The evidence for a potential benefit of antioxidant vitamins in the prevention and therapy of atherosclerotic disease is derived from laboratory, clinical, and observational epidemiologic studies but remains inconclusive. Data from randomized clinical trials are sparse, particularly for women. Therefore, it is both timely and important to conduct large-scale primary and secondary prevention trials of antioxidants and cardiovascular disease (CVD). The Women's Antioxidant and Cardiovascular Study (WACS) is a randomized, double-blind, placebo-controlled secondary prevention trial of the balance of benefits and risks of antioxidant vitamins (vitamins E and C, and beta-carotene) among 8000 women with preexisting CVD. This secondary prevention trial will be conducted as a companion to the recently started Women's Health Study, a primary prevention trial of vitamin E and beta-carotene, as well as aspirin. In the WACS, US female health professionals aged 40 years and older with a history of myocardial infarction, angina pectoris, coronary revascularization, stroke, transient cerebral ischemia, carotid endarterectomy, or peripheral artery surgery will be randomly assigned, utilizing a 2 x 2 x 2 factorial design, to receive vitamin E, vitamin C, beta-carotene, and/or placebo. Cardiovascular end points include nonfatal myocardial infarction, nonfatal stroke, coronary revascularization procedures, and total CVD mortality. The present article describes the rationale, design, and methods of the trial.

Current and future perspectives on antithrombotic therapy of acute myocardial infarction

Randomised trials of coronary artery patency and mortality support the routine use of antithrombotic therapy in all patients with suspected acute myocardial infarction. At present, it is unclear whether antiplatelet therapy with aspirin alone will suffice or the addition of anticoagulation with either heparin or the newer specific thrombin inhibitor, hirudin, will confer a net benefit. The ongoing randomised trials, such as GUSTO-2 and TIMI-9, will provide relevant information on the use of aspirin plus heparin or aspirin plus hirudin in patients treated with thrombolytic therapy. The First American Study of Infarct Survival (ASIS-1) will provide data which are relevant to the large population of patients who, in the United States, do not receive thrombolytic therapy. When these data become available it will be possible for clinicians to make rational individual decisions and policy-makers to formulate guidelines concerning optimal antithrombotic therapy in myocardial infarction.

Discrimination in absorption or transport of beta-carotene isomers after oral supplementation with either all-trans- or 9-cis-beta-carotene

Human subjects (n = 24) were supplemented with 100 mg beta-carotene/d for 6 d, either as synthetic all-trans-beta-carotene or a natural beta-carotene preparation derived from the alga Dunaliella salina, which consists of a 50:50 mixture of all-trans- and 6-cis-beta-carotene. This loading dose was followed by a 23-d maintenance dose consisting of alternate-day supplementation with 50 mg all-trans-beta-carotene or either 66 or 100 mg of the natural 50:50 isomeric mixture. The loading dose resulted in significant increases in plasma concentrations of both isomers, with the all-trans-beta-carotene-supplemented group showing a 7.2- and 5.0-fold increase in the all-trans and 9-cis concentrations in plasma, respectively. The group receiving the 50:50 mixture showed a 4.0- and 3.7-fold increase in the all-trans and 9-cis concentrations in plasma, respectively, without any apparent dose-dependency. However, even with the 50:50 mixture, the 9-cis concentrations were only a small fraction of the total plasma beta-carotene. Results after an additional 23-d period of alternate-day supplementation were not significantly different from those described above for the 6-d supplementation. Increases in low-density-lipoprotein concentrations of total beta-carotene correlated strongly with the increases seen in plasma concentrations. Lipid-soluble antioxidants vitamin E and ubiquinol were unaffected by beta-carotene supplementation. However, the amount of lycopene in the low-density lipoprotein decreased during this supplementation period. A strong discrimination between these two geometric isomers of beta-carotene was demonstrated, although the tissue site of discrimination was not determined.

Antithrombotic therapy for acute myocardial infarction

Antithrombotic therapy is clearly beneficial in the treatment of acute myocardial infarction, but the optimal regimen is controversial. Treatment with aspirin leads to substantial and significant reductions in rates of mortality, reinfarction and stroke in patients with acute myocardial infarction, and the benefits are additive with those of thrombolytic therapy. It is unclear whether heparin confers additional net benefits over aspirin alone. In patients receiving aspirin and thrombolytic therapy, there is no mortality benefit from adding delayed subcutaneous heparin, no consistent patency benefit from adding immediate intravenous heparin and no reduction in mortality from adding immediate intravenous heparin, at least for patients treated with streptokinase. However, heparin is consistently associated with increased rates of intracranial and other serious bleeding events when used with both aspirin and thrombolytic therapy. Existing data support the need for further large-scale trials of current and newer antithrombotic regimens in acute myocardial infarction to assess the balance of benefits and risks of these regimens compared with that for aspirin alone. In patients not receiving thrombolytic therapy, randomized trial data are currently insufficient to adequately compare the benefits and risks of adding heparin to aspirin alone. The First American Study of Infarct Survival (ASIS-1) will directly compare the balance of risks and benefits of aspirin alone, aspirin plus intravenous heparin and aspirin plus intravenous hirudin in patients with acute myocardial infarction not receiving thrombolytic therapy.

Current issues concerning thrombolytic therapy for acute myocardial infarction

Data are now available from three large-scale randomized trials that directly compare the risks and benefits of thrombolytic agents in acute myocardial infarction. In the interpretation of results from the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI-2) trial and its International Extension, the Third International Study of Infarct Survival (ISIS-3), and the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-1) trial, there are areas of both agreement and controversy. It is generally agreed that the agents most commonly used in the United States--tissue-type plasminogen activator (t-PA), streptokinase and anisoylated plasminogen streptokinase activator complex (APSAC)--all reduce mortality when given to patients with acute evolving myocardial infarction. Further, it is clear that thrombolytic therapy given to such patients presenting up to 12 h after onset of symptoms reduces the mortality rate by approximately 20%, that aspirin therapy for patients presenting up to 24 h reduces the mortality rate by approximately 23% and that the benefits of thrombolytic therapy and aspirin are additive. Finally, and of most importance, the earlier administration as well as the more widespread use of thrombolytic therapy and aspirin would save many more lives. The totality of evidence clearly indicates that streptokinase produces significantly fewer strokes and cerebral hemorrhages than either t-PA or APSAC. Whether or not accelerated t-PA has a small advantage for mortality is less conclusive.(ABSTRACT TRUNCATED AT 250 WORDS)

Man-made vitreous fibers and risk of respiratory system cancer: a review of the epidemiologic evidence

Because asbestos has been demonstrated to cause lung cancer, the issue regarding safety of other fibers, including man-made vitreous fibers (MMVF), has been raised. We reviewed the available evidence, in particular the epidemiologic data, on MMVF and the risk of respiratory system cancer. Glass fibers (especially glass wool) have been studied most extensively. Taken together, the data indicate that among those occupationally exposed, glass fibers do not appear to increase risk of respiratory system cancer. Of six studies that specifically examined rock and slag wool workers, three reported excesses in respiratory system cancer among such workers. Two of these three studies, however, did not control for cigarette smoking, a powerful predictor of such cancers. There are no published studies, in humans, of refractory ceramic fibers. Future studies evaluating the potential of MMVF to increase risk of respiratory system cancer will not add to existing knowledge if investigators do not address potential confounding by cigarette smoking and other workplace carcinogens.

Alcohol consumption and mortality among women

BACKGROUND

Studies in men suggest that light-to-moderate alcohol intake is associated with a reduction in overall mortality, due primarily to a reduced risk of coronary heart disease. Among women with similar levels of alcohol consumption, an increased risk of breast cancer has been noted that complicates the balance of risks and benefits.

METHODS

We conducted a prospective study among 85,709 women, 34 to 59 years of age and without a history of myocardial infarction, angina, stroke, or cancer, who completed a dietary questionnaire in 1980. During the 12-year follow-up period, 2658 deaths were documented.

RESULTS

The relative risks of death in drinkers as compared with nondrinkers were 0.83 (95 percent confidence interval, 0.74 to 0.93) for women who consumed 1.5 to 4.9 g of alcohol per day (one to three drinks per week), 0.88 (95 percent confidence interval, 0.80 to 0.98) for those who consumed 5.0 to 29.9 g per day, and 1.19 (95 percent confidence interval, 1.02 to 1.38) for those who consumed 30 g or more per day, after adjustment for other predictors of mortality. Light-to-moderate drinking (1.5 to 29.9 g per day) was associated with a decreased risk of death from cardiovascular disease; heavier drinking was associated with an increased risk of death from other causes, particularly breast cancer and cirrhosis. The benefit associated with light-to-moderate drinking was most apparent among women with risk factors for coronary heart disease and those 50 years of age or older.

CONCLUSIONS

Among women, light-to-moderate alcohol consumption is associated with a reduced mortality rate, but this apparent survival benefit appears largely confined to women at greater risk for coronary heart disease.

Relationship of alcohol intake with blood pressure in young adults

The objective of this study was to examine the relationship of usual current alcohol intake with systolic and diastolic pressures among young adults. Participants were 316 men and women, aged 18 to 26 years, from East Boston, Mass. At each of three weekly visits we obtained three blood pressure measurements on each subject using a random-zero sphygmomanometer. Using an interviewer-administered questionnaire, we obtained information about quantity and frequency of alcohol intake during the previous month. The lowest systolic pressure levels were in subjects consuming 1 to < 2 drinks per day. Adjusted for age, sex, and body mass index, systolic pressure was higher by 4.0 mm Hg (95% confidence interval [CI], 0.5 to 7.6 mm Hg) in abstainers, 3.6 mm Hg (95% CI, 0.5 to 6.6 mm Hg) in those who drank < 1 drink per day, 0.4 mm Hg (95% CI, -4.7 to 5.5 mm Hg) in those who drank 2 to < 3 drinks per day, and 8.1 mm Hg (95% CI, 2.9 to 13.4 mm Hg) in those who drank > or = 3 drinks per day. Levels of diastolic pressure were lowest in those consuming 2 to < 3 drinks per day. Adjustment for pulse rate, smoking, medication use, and family history of hypertension did not alter the results. These results suggest a J-shaped association of alcohol intake with blood pressure level in young adults, with the lowest levels in consumers of 1 to 3 drinks per day.

Plasma concentration of lipoprotein(a) and the risk of future stroke

OBJECTIVE

To assess prospectively the risk of future stroke associated with baseline concentration of lipoprotein(a), abbreviated Lp(a).

DESIGN

Nested case-control study using baseline plasma samples.

SETTING

Men in the Physicians' Health Study.

PARTICIPANTS

A cohort of 14,916 male physicians with no prior history of stroke, transient ischemic attack, or myocardial infarction provided plasma samples at baseline and were followed prospectively for 7.5 years. Samples from 198 physicians who subsequently developed stroke (155 thromboembolic, 35 hemorrhagic, eight indeterminate) were analyzed for Lp(a) concentration together with paired controls, matched for age and smoking habit.

MAIN OUTCOME MEASURE

Fatal and nonfatal stroke.

RESULTS

Median Lp(a) concentration (8.88 mg/dL [0.23 mmol/L] vs 8.55 mg/dL [0.22 mmol/L]), P = .69) and overall distributions of Lp(a) (P = .54) were similar at baseline in men who did and did not develop future stroke. In analyses controlling for age, smoking status, blood pressure, obesity, and the presence of diabetes, the relative risks (RRs) associated with baseline Lp(a) concentration exceeding the 25th, 50th, 75th, 90th, and 95th percentiles of the control distribution were 1.26, 0.99, 1.06, 0.90, and 1.03 (all P values nonsignificant). There was likewise no association in analyses limited to thromboembolic events. For example, among subjects with baseline Lp(a) values exceeding the 95th percentile of the control distribution, the RR of future thromboembolic stroke was 1.01 (P = .9). No evidence of association between Lp(a) and stroke risk was found in analyses limited to individuals with hypercholesterolemia.

CONCLUSIONS

Among nearly 15,000 predominantly white, healthy, middle-aged men followed in the Physicians' Health Study for a period of 7.5 years, we found no evidence of association between baseline plasma concentration of Lp(a) and future risk of total or thromboembolic stroke.

Implications of small reductions in diastolic blood pressure for primary prevention

OBJECTIVES

To estimate the impact of small reductions in the population distribution of diastolic blood pressure (DBP), such as those potentially achievable by population-wide lifestyle modification, on incidence of coronary heart disease (CHD) and stroke.

DESIGN

Published data from the Framingham Heart Study, a longitudinal cohort study, and from the National Health and Nutrition Examination Survey II, a national population survey, were used to examine the impact of a population-wide strategy aimed at reducing DBP by an average of 2 mm Hg in a population including normotensive subjects.

SETTING/PARTICIPANTS

White men and women aged 35 to 64 years in the United States.

MAIN OUTCOME MEASURES

Incidence of CHD and stroke, including transient ischemic attacks (TIAs).

RESULTS

Data from overviews of observational studies and randomized trials suggest that a 2-mm Hg reduction in DBP would result in a 17% decrease in the prevalence of hypertension as well as a 6% reduction in the risk of CHD and a 15% reduction in risk of stroke and TIAs. From an application of these results to US white men and women aged 35 to 64 years, it is estimated that a successful population intervention alone could reduce CHD incidence more than could medical treatment for all those with a DBP of 95 mm Hg or higher. It could prevent 84% of the number prevented by medical treatment for all those with a DBP of 90 mm Hg or higher. For stroke (including TIAs), a population-wide 2-mm Hg reduction could prevent 93% of events prevented by medical treatment for those with a DBP of 95 mm Hg or higher and 69% of events for treatment for those with a DBP of 90 mm Hg or higher. A combination strategy of both a population reduction in DBP and targeted medical intervention is most effective and could double or triple the impact of medical treatment alone. Adding a population-based intervention to existing levels of hypertension treatment could prevent an estimated additional 67,000 CHD events (6%) and 34,000 stroke and TIA events (13%) annually among all those aged 35 to 64 years in the United States.

CONCLUSIONS

A small reduction of 2 mm Hg in DBP in the mean of the population distribution, in addition to medical treatment, could have a great public health impact on the number of CHD and stroke events prevented. Whether such DBP reductions can be achieved in the population through lifestyle interventions, in particular through sodium reduction, depends on the results of ongoing primary prevention trials as well as the cooperation of the food industry, government agencies, and health education professionals.

Mutation in the gene coding for coagulation factor V and the risk of myocardial infarction, stroke, and venous thrombosis in apparently healthy men

BACKGROUND

A specific point mutation in the gene coding for coagulation factor V is associated with resistance to degradation by activated protein C, a recently described abnormality of coagulation that may be associated with an increased risk of venous thrombosis. Whether this mutation also predisposes patients to arterial thrombosis is unknown, as is the value of screening for the mutation in order to define the risk of venous thrombosis among unselected healthy people.

METHODS

Among 14,916 apparently healthy men in the Physicians' Health Study who provided base-line blood samples, 374 had myocardial infarctions, 209 had strokes, and 121 had deep venous thrombosis, pulmonary embolism, or both, during a mean follow-up of 8.6 years. We determined whether a mutation at nucleotide position 1691 of the factor V gene was present or absent in these 704 men and in an equal number of matched participants who remained free of vascular disease.

RESULTS

The prevalence of heterozygosity for the mutation among men who had myocardial infarctions (6.1 percent, P = 0.9) or strokes (4.3 percent, P = 0.4) was similar to that among men who remained free of vascular disease (6.0 percent). However, the prevalence of the mutation was significantly higher among men who had venous thrombosis, pulmonary embolism, or both (11.6 percent, P = 0.02). In adjusted analyses, the relative risk of venous thrombosis among men with the mutation was 2.7 (95 percent confidence interval, 1.3 to 5.6; P = 0.008). This increased risk was seen with primary venous thrombosis (relative risk, 3.5; 95 percent confidence interval, 1.5 to 8.4; P = 0.004) but not with secondary venous thrombosis (relative risk, 1.7; 95 percent confidence interval, 0.6 to 5.3; P = 0.3), and it was most apparent among older men. Specifically, the prevalence of the mutation among men over the age of 60 in whom primary venous thrombosis developed was 25.8 percent (relative risk, 7.0; 95 percent confidence interval, 2.6 to 19.1; P < 0.001).

CONCLUSIONS

In a large cohort of apparently healthy men, the presence of a specific point mutation in the factor V gene was associated with an increased risk of venous thrombosis, particularly primary venous thrombosis. The presence of the mutation was not associated with an increased risk of myocardial infarction or stroke. This mutation appears to be the most common inherited factor thus far recognized that predisposes patients to venous thrombosis.

Evidence for a positive linear relation between blood pressure and mortality in elderly people

Many studies of blood pressure in the elderly have found higher death rates in groups with the lowest blood pressure than in those with intermediate values. In a large community study, we examined whether these findings are real or artifacts of short follow-up, co-morbidity, or low blood pressure in people near death. In 1982-83, we assessed drug use, medical history, disability, physical function, and blood pressure in 3657 residents of East Boston, Massachusetts, aged 65 and older. We identified all deaths (1709) up to 1992 and followed up survivors for an average of 10.5 (range 9.5-11.0) years. After adjustment for confounding variables (including frailty and disorders such as congestive heart failure and myocardial infarction) and exclusion of deaths within the first 3 years of follow-up, higher systolic pressure predicted linear increases in cardiovascular (p < 0.0001) and total (p < 0.0007) mortality. Higher diastolic pressure predicted increases in cardiovascular (p = 0.006) but not total (p = 0.48) mortality. These results differed from those for the first 3 years, during which groups with the lowest systolic and diastolic pressures had the highest death rates. In the long term, lower blood pressure in old age, as in middle age, is associated with better survival. Short-term findings may differ because of associations of co-morbidity and frailty with blood pressure near death. Overall, the findings support recommendations to treat high blood pressure in elderly people.

A prospective evaluation of an angiotensin-converting-enzyme gene polymorphism and the risk of ischemic heart disease

BACKGROUND

In a previous study, men with a history of myocardial infarction were found to have an increased prevalence of homozygosity for the deletional allele (D) of the angiotensin-converting-enzyme (ACE) gene. The D allele is associated with higher levels of ACE, which may predispose a person to ischemic heart disease. We investigated the association between the ACE genotype and the incidence of myocardial infarction, as well as other manifestations of ischemic heart disease, in a large, prospective cohort of U.S. male physicians.

METHODS

In the Physicians' Health Study, ischemic heart disease as defined by angina, coronary revascularization, or myocardial infarction developed in 1250 men by 1992. They were matched with 2340 controls according to age and smoking history. Zygosity for the deletion-insertion (D-I) polymorphism of the ACE gene was determined by an assay based on the polymerase chain reaction. Data were analyzed for both matched pairs and unmatched samples, with adjustment for the effects of known or suspected risk factors by conditional and nonconditional logistic regression, respectively.

RESULTS

The ACE genotype was not associated with the occurrence of either ischemic heart disease or myocardial infarction. The adjusted relative risk associated with the D allele was 1.07 (95 percent confidence interval, 0.96 to 1.19; P = 0.24) for ischemic heart disease and 1.05 (95 percent confidence interval, 0.89 to 1.25; P = 0.56) for myocardial infarction, if an additive mode of inheritance is assumed. Additional analyses assuming dominant and recessive effects of the D allele also failed to show any association, as did the examination of low-risk subgroups.

CONCLUSIONS

In a large, prospectively followed population of U.S. male physicians, the presence of the D allele of the ACE gene conferred no appreciable increase in the risk of ischemic heart disease or myocardial infarction.

Lack of blood pressure effect with calcium and magnesium supplementation in adults with high-normal blood pressure. Results from Phase I of the Trials of Hypertension Prevention (TOHP). Trials of Hypertension Prevention (TOHP) Collaborative Research Group

Phase I of the Trials of Hypertension Prevention (TOHP) was a randomized, multicenter investigation that included double-blind, placebo-controlled testing of calcium and magnesium supplementation among 698 healthy adults (10.5% blacks and 31% women) aged 30 to 54 years with high-normal diastolic blood pressure (DBP) (80 to 89 mm Hg). Very high compliance (94 to 96% by pill counts) with daily doses of 1 g of calcium (carbonate), 360 mg of magnesium (diglycine), or placebos was corroborated for the active supplements by significant net increases in all urine and serum compliance measures in white men and for urine compliance measures in white women. Overall, neither calcium nor magnesium produced significant changes in blood pressure at 3 and 6 months. Analyses stratified by baseline intakes of calcium, magnesium, sodium, or initial blood pressures also showed no effect of supplementation. These analyses suggested that calcium supplementation may have resulted in a DBP decrease in white women and that response modifiers in this subgroup might have included lower initial urinary calcium levels, urinary sodium levels, or lower body mass index. However, overall analyses indicated that calcium and magnesium supplements are unlikely to lower blood pressure in adults with high-normal DBP. The subgroup analyses, useful to formulate hypotheses, raise the possibility of a benefit to white women, which requires testing in future trials.

Weight, weight change, and coronary heart disease in women. Risk within the 'normal' weight range

OBJECTIVE--To assess the validity of the 1990 US weight guidelines for women that support a substantial gain in weight at approximately 35 years of age and recommend a range of body mass index (BMI) (defined as weight in kilograms divided by the square of height in meters) from 21 to 27 kg/m2, in terms of coronary heart disease (CHD) risk in women. DESIGN--Prospective cohort study. SETTING--Female registered nurses in the United States. PARTICIPANTS--A total of 115,818 women aged 30 to 55 years in 1976 and without a history of previous CHD. MAIN OUTCOME MEASURE--Incidence of CHD defined as nonfatal myocardial infarction or fatal CHD. RESULTS--During 14 years of follow-up, 1292 cases of CHD were ascertained. After controlling for age, smoking, menopausal status, postmenopausal hormone use, and parental history of CHD and using as a reference women with a BMI of less than 21 kg/m2, relative risks (RRs) and 95% confidence intervals (CIs) for CHD were 1.19 (0.97 to 1.44) for a BMI of 21 to 22.9 kg/m2, 1.46 (1.20 to 1.77) for a BMI of 23 to 24.9 kg/m2, 2.06 (1.72 to 2.48) for a BMI of 25 to 28.9 kg/m2, and 3.56 (2.96 to 4.29) for a BMI of 29 kg/m2 or more. Women who gained weight from 18 years of age were compared with those with stable weight (+/- 5 kg) in analyses that controlled for the same variables as well as BMI at 18 years of age. The RRs and CIs were 1.25 (1.01 to 1.55) for a 5- to 7.9-kg gain, 1.64 (1.33 to 2.04) for an 8- to 10.9-kg gain, 1.92 (1.61 to 2.29) for an 11- to 19-kg gain, and 2.65 (2.17 to 3.22) for a gain of 20 kg or more. Among women with the BMI range of 18 to 25 kg/m2, weight gain after 18 years of age remained a strong predictor of CHD risk. CONCLUSIONS--Higher levels of body weight within the "normal" range, as well as modest weight gains after 18 years of age, appear to increase risks of CHD in middle-aged women. These data provide evidence that current US weight guidelines may be falsely reassuring to the large proportion of women older than 35 years who are within the current guidelines but have potentially avoidable risks of CHD.

Childhood socioeconomic status and risk of cardiovascular disease in middle aged US women: a prospective study

OBJECTIVE

To examine prospectively the relationship of childhood socioeconomic status and risk of cardiovascular disease in middle aged women.

DESIGN

A prospective cohort of women with 14 years follow up data (1976-90).

SUBJECTS

A total of 117,006 registered female nurses aged 30 to 55 years in 1976 and free of diagnosed coronary heart disease, stroke, and cancer at baseline.

MAIN OUTCOME MEASURES

Incident fatal coronary heart disease, non-fatal myocardial infarction, and stroke (fatal and non-fatal).

RESULTS

Low socioeconomic status in childhood was associated with a modestly increased risk of incident non-fatal myocardial infarction and total cardiovascular disease in adulthood. Compared with middle aged women from white collar childhood backgrounds, the age adjusted risk of total cardiovascular disease for women from blue collar backgrounds was 1.13 (95% CI 1.02, 1.24) and that of non-fatal myocardial infarction was 1.23 (95% CI 1.06, 1.42). No significant increase in risk was observed for stroke or fatal coronary heart disease. Adjustment for differences in family and personal past medical history, medication use, exercise, alcohol intake, diet, birth weight, being breastfed in infancy, and adult socioeconomic circumstance somewhat attenuated the increased risks observed for women from blue collar childhood socioeconomic backgrounds. In multivariate analysis, women whose fathers had been manual labourers had the highest relative risk of total coronary heart disease (RR = 1.53; 95% CI 1.09, 2.16) and non-fatal myocardial infarction (RR = 1.67; 95% CI 1.11, 2.53) when compared with women whose fathers had been employed in the professions.

CONCLUSION

In this group lower childhood socioeconomic status was associated with a small but significant increase in the risk of total coronary heart disease as well as non-fatal myocardial infarction. For women from the most socioeconomically disadvantaged childhood backgrounds, the association is not explained by differences in a large number of cardiovascular risk factors, by differences in adult socioeconomic status, or by differences in indices of nutrition during gestation or infancy.

A prospective study of plasma fish oil levels and incidence of myocardial infarction in U.S. male physicians

OBJECTIVES

This study evaluated whether increased intake of fish oils (eicosapentaenoic and docosahexaenoic acids) might reduce the risk of coronary heart disease.

BACKGROUND

Observational and clinical studies have suggested that increased intake of fish oils, as reflected in plasma levels of fish oils, may reduce the risk of myocardial infarction.

METHODS

A nested case-control study was conducted among the 14,916 participants in the Physicians' Health Study with a sample of plasma before randomization. Each participant with myocardial infarction occurring during the first 5 years of follow-up was matched by smoking status and age with a randomly chosen control participant who had not developed coronary heart disease.

RESULTS

Mean levels of fish oils (with 95% confidence interval [CI] for paired differences and p values) in case and control participants, expressed as percent of total fatty acids, were, for eicosapentaenoic acid, 0.26 versus 0.25 (95% CI -0.03 to 0.05, p = 0.70) in cholesterol esters and 0.56 versus 0.54 (95% CI -0.04 to 0.09, p = 0.44) in phospholipids, and for docosahexaenoic acid, 0.23 versus 0.24 (95% CI -0.07 to 0.04, p = 0.64) in cholesterol esters and 2.22 versus 2.14 (95% CI -0.10 to 0.27, p = 0.36) in phospholipids. Results adjusted for major cardiovascular risk factors showed a very similar lack of association between fish oil levels and the incidence of myocardial infarction.

CONCLUSIONS

These results indicate no beneficial effect of increased fish oil consumption on the incidence of a first myocardial infarction. However, the effect of very high levels of fish oils could not be evaluated.

A prospective evaluation of plasma prostate-specific antigen for detection of prostatic cancer

OBJECTIVE

To evaluate the validity of prostate-specific antigen (PSA) in identifying men who subsequently were or were not clinically diagnosed with prostate cancer, assess optimal test cutoff, measure lead time, and estimate relative risks (RRs) associated with discrete PSA levels.

DESIGNS

Nested case-control study of men providing plasma samples before a 10-year follow-up.

SETTING

The Physicians' Health Study, an ongoing randomized trial that enrolled 22,071 men aged 40 to 84 years in 1982.

PARTICIPANTS

A total of 366 men (cases) diagnosed with prostate cancer and 1098 men (three controls per case), matched by age, randomly selected from all cohort members at risk at the time of case diagnosis.

MAIN OUTCOME MEASURES

Sensitivity and specificity for each year of follow-up and for aggressive and nonaggressive cancers separately.

RESULTS

At a cutoff of 4.0 ng/mL, sensitivity for the entire 10-year follow-up was 46% for total cases. Sensitivities for detection of total, aggressive, and nonaggressive cancers occurring in the first 4 years were 73%, 87%, and 53%. Overall, specificity was 91% and changed little by year of follow-up. Optimal validity was achieved at a cutoff of 3.3 ng/mL. Estimated mean lead time for all cancers was 5.5 years. Only 40% of cancers detected more than 5 years from baseline were nonaggressive. Compared with men with PSA levels less than 1.0 ng/mL, those with PSA levels between 2.0 and 3.0 ng/mL had an RR of 5.5 (95% confidence interval, 3.7 to 9.2).

CONCLUSIONS

A single PSA measurement had a relatively high sensitivity and specificity for detection of prostate cancers that arose within 4 years. Prostate-specific antigen values less than the usual cutoff were associated with substantial increases in risk compared with the lowest levels. Final evaluation of PSA screening must also consider cost and the ability of current treatments to improve the prognosis of screen-detected cases.

Supplementation with beta-carotene in vivo and in vitro does not inhibit low density lipoprotein oxidation

The inhibition of low density lipoprotein (LDL) oxidation has been postulated as one mechanism by which antioxidants may prevent the development of atherosclerosis. Available data on the ability of beta-carotene to inhibit LDL oxidation are conflicting. We examined the role of in vivo and in vitro supplementation with beta-carotene on metal ion-dependent (cupric ions, Cu2+) and metal ion-independent (2,2'-azobis[2-amidinopropane]dihydrochloride, AAPH) oxidation of LDL as measured by the formation of conjugated dienes (absorbance at 234 nm). Sixteen subjects were supplemented with 50-100 mg of beta-carotene on alternate days for 3 weeks following a week-long loading dose of 100 mg/day. Plasma beta-carotene levels rose 5.5-fold, while LDL beta-carotene levels rose 8.5-fold. Oxidation of LDL by Cu2+ or AAPH was not significantly delayed after in vivo supplementation with beta-carotene compared with baseline. For AAPH, the lag phase (in minutes) was 75 +/- 8 at baseline and 83 +/- 14 after supplementation (P = 0.07). For Cu2+, the lag phase was 172 +/- 41 at baseline and decreased to 130 +/- 24 after supplementation (P < 0.01). Similarly, no protective effect against Cu(2+)-induced oxidation was observed when beta-carotene was added to LDL in vitro. Supplementation of plasma with beta-carotene in vitro prior to LDL isolation also did not enhance LDL's resistance to Cu(2+)- or AAPH-induced oxidation, despite a 5-fold increase in LDL beta-carotene levels over vehicle control.(ABSTRACT TRUNCATED AT 250 WORDS)