The multiple risk factor intervention trial (MRFIT) II. The development of the protocol

Association of risk factors with type 2 diabetes: A systematic review

Diabetes is the leading cause of severe health complications and one of the top 10 causes of death worldwide. To date, diabetes has no cure, and therefore, it is necessary to take precautionary measures to avoid its occurrence. The main aim of this systematic review is to identify the majority of the risk factors for the incidence/prevalence of type 2 diabetes mellitus on one hand, and to give a critical analysis of the cohort/cross-sectional studies which examine the impact of the association of risk factors on diabetes. Consequently, we provide insights on risk factors whose interactions are major players in developing diabetes. We conclude with recommendations to allied health professionals, individuals and government institutions to support better diagnosis and prognosis of the disease.

Weight loss for overweight and obese individuals with gout: a systematic review of longitudinal studies

OBJECTIVES

Weight loss is commonly recommended for gout, but the magnitude of the effect has not been evaluated in a systematic review. The aim of this systematic review was to determine benefits and harms associated with weight loss in overweight and obese patients with gout.

METHODS

We searched six databases for longitudinal studies, reporting the effect of weight loss in overweight/obese gout patients. Risk of bias was assessed using the tool Risk of Bias in Non-Randomised Studies of Interventions. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation.

RESULTS

From 3991 potentially eligible studies, 10 were included (including one randomised trial). Interventions included diet with/without physical activity, bariatric surgery, diuretics, metformin or no intervention. Mean weight losses ranged from 3 kg to 34 kg. Clinical heterogeneity in study characteristics precluded meta-analysis. The effect on serum uric acid (sUA) ranged from -168 to 30 μmol/L, and 0%-60% patients achieving sUA target (<360 μmol/L). Six out of eight studies (75%) showed beneficial effects on gout attacks. Two studies indicated dose-response relationship for sUA, achieving sUA target and gout attacks. At short term, temporary increased sUA and gout attacks tended to occur after bariatric surgery.

CONCLUSIONS

The available evidence is in favour of weight loss for overweight/obese gout patients, with low, moderate and low quality of evidence for effects on sUA, achieving sUA target and gout attacks, respectively. At short term, unfavourable effects may occur. Since the current evidence consists of a few studies (mostly observational) of low methodological quality, there is an urgent need to initiate rigorous prospective studies (preferably randomised controlled trials).

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42016037937.

Obesity Paradox in Recurrent Attacks of Gout in Observational Studies: Clarification and Remedy

OBJECTIVE

Obesity is strongly associated with incident gout risk, but its association with the risk of recurrent gout attacks has been null or weak, constituting an obesity paradox. We sought to demonstrate and overcome the methodologic issues associated with the obesity paradox for risk of recurrent gout attacks.

METHODS

Using the Multiple Risk Factor Intervention Trial database, we decomposed the total effect of obesity into its direct and indirect (i.e., mediated) effects using marginal structural models. We also estimated the total effect of body mass index (BMI) change from baseline among incident gout patients.

RESULTS

Of 11,816 gout-free subjects at baseline, we documented 408 incident gout cases, with 132 developing recurrent gout attacks over a 7-year followup period. The adjusted odds ratio (OR) for incident gout among obese individuals was 2.6, whereas that for recurrent gout attacks among gout patients was 0.98 (i.e., the obesity paradox). These ORs correlated well with the ORs for the indirect and direct effects of obesity on the risk of recurrent gout attacks (2.83 and 0.98, respectively). Compared with no BMI change, the OR of increasing versus decreasing >5% of baseline BMI was 0.61 and 1.60 for recurrent gout attacks, respectively (P for trend < 0.01), suggesting a dose-response association.

CONCLUSION

The obesity paradox for the risk of recurrent gout attacks is explained by the absence of the direct effect, which is often measured in conventional analyses and misinterpreted as the intended total effect of interest. In contrast, the BMI change analysis correctly estimated the intended total effect of BMI, and revealed a dose-response relationship.

Multiple-stage screening and mortality in the Multiple Risk Factor Intervention Trial

Background During the design phase of a clinical trial, sample size estimates should take into account medical screening criteria, the ‘healthy volunteer’ effect, consequences of run-in phases, and secular trends in the event rate of interest. All of these have been shown to relate to subsequent event rates, and hence trial power to detect intervention effects. The Multiple Risk Factor Intervention Trial (MRFIT) used three successive screenings of 361 662 men to enroll 12 866; observed coronary heart disease (CHD) mortality after a mean of 6.9 years was substantially lower than projected during design. We explore factors which may have contributed to these mortality differences and whether they persisted throughout follow-up.

Methods Proportional hazards models were used to compare 25-year mortality according to trial eligibility, self-exclusions, medical exclusions, and participation.

Results After adjustment for baseline risk factors and age, there was higher mortality among men excluded for presence of disease [hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.43–1.61, for total; HR 1.92, CI 1.75–2.11, for CHD] compared to those not excluded which persisted throughout follow-up. Volunteers had lower total (HR 0.82, CI 0.76–0.87) and CHD (HR 0.79, CI 0.70–0.88) mortality than those discontinuing participation. Men excluded with characteristics deemed likely to interfere with adherence had higher total (HR 1.19, CI 1.07–1.33) and noncardiovascular disease (CVD) (HR 1.32, CI 1.14–1.53) mortality but no higher CVD (HR 1.04, CI 0.88–1.23) or CHD (HR 0.98, CI 0.80–1.20) mortality compared to those not excluded. Differences in mortality were stronger during the first five years, but declined only slightly over 25 years.

Conclusions 25-year mortality was significantly higher for non-volunteers and exclusions. Differences between observed and predicted six-year total mortality for trial participants were largely attributable to volunteers and exclusions, but there were additional differences for CHD mortality, which were likely due to downward secular trends. These results emphasize the importance of anticipating these factors during clinical trial design, even for trials of short duration.

Gout in African Americans

PURPOSE

African Americans have a substantially higher prevalence of risk factors for gout than Caucasians. The aim of the present study was to compare the risk for incident gout among African Americans and Caucasians.

METHODS

Incidence rates of physician-diagnosed gout among 11,559 Caucasian men and 931 African American men aged 35 to 57 years and at high cardiovascular risk, observed for 7 years as a part of the Multiple Risk Factor Intervention Trial, were analyzed. Cox regression models were used to account for potential confounding by age, body mass index, diuretic use, hypertension and diabetes status, aspirin and alcohol consumption, and kidney disease.

RESULTS

At baseline, after accounting for risk factors, African Americans had a 14% lower prevalence of hyperuricemia than Caucasians. Incidence of gout increased with increasing prevalence of risk factors in both Caucasians and African Americans. Ethnic disparities in incidence rates were most apparent among those without other risk factors for gout. In separate Cox regression models, after accounting for risk factors, African American ethnicity was associated with a hazard ratio of 0.78 (95% confidence interval [CI], 0.66-0.93) for physician-diagnosed gout and 0.88 (95% CI, 0.85-0.90) for incident hyperuricemia. Significant interactions were observed; the association was the strongest (hazard ratio 0.47; 0.37-0.60). These associations were unaffected by addition of serum urate as a covariate or by using alternate case definitions for gout.

CONCLUSIONS

After accounting for the higher prevalence of risk factors, African American ethnicity is associated with a significantly lower risk for gout and hyperuricemia compared with Caucasian ethnicity.

Chronic kidney disease and the risk of incident gout among middle-aged men: a seven-year prospective observational study

OBJECTIVE

The kidney is the major organ that facilitates excretion of urate in humans. Surprisingly, few studies have assessed whether a reduced glomerular filtration rate (GFR) and/or kidney damage is associated with a higher incidence of gout, and this study was undertaken to address this question.

METHODS

Data from a 7-year followup of patients enrolled in the Multiple Risk Factor Intervention Trial, a primary prevention trial for cardiovascular disease among 12,866 men ages 35-57 years, were used for the present investigation. Presence of gout was determined by the study physicians from the original trial. Chronic kidney disease was defined using criteria similar to those proposed by the National Kidney Foundation. The Cox proportional hazards regression model was used to assess the association between gout and chronic kidney disease, after accounting for the effects of potential confounders.

RESULTS

Overall, there were 722 cases of physician- diagnosed incident gout over 76,602 person-years of followup. The standardized incidence ratio of gout among those with chronic kidney disease was 1,217 (95% confidence interval [95% CI] 1,191-1,244). The adjusted hazard ratio (HR) among those with chronic kidney disease was 1.61 (95% CI 1.60-1.61). Each standard deviation decline in the estimated GFR was associated with an HR of 1.43 (95% CI 1.35-1.51). Including the serum urate level, as well as the urate-chronic kidney disease interaction term, as variables in the second analysis did not attenuate the HR. Proteinuria and hematuria, two markers of kidney damage, were associated with an elevated risk of gout independent of the estimated GFR.

CONCLUSION

Chronic kidney disease manifesting as reduced glomerular function or as presence of blood or protein in the urine increases the risk of incident gout.

Multiple risk factor intervention trial revisited: a new perspective based on nonfatal and fatal composite endpoints, coronary and cardiovascular, during the trial

Background

The Multiple Risk Factor Intervention Trial evaluated a multifactor intervention on coronary heart disease (CHD) in 12 866 men. A priori defined endpoints (CHD death, CHD death or nonfatal myocardial infarction, cardiovascular disease [CVD] death, and all-cause death) did not differ significantly between the special intervention (SI) and usual care (UC) groups over an average follow-up period of 7 years. Event rates were lower than anticipated, reducing power. Other nonfatal CVD outcomes were prespecified but not considered in composite outcomes comparing SI with UC.

Methods and Results

Post-trial CVD mortality risks associated with nonfatal CVD events occurring during the trial were determined with Cox regression. Nonfatal outcomes associated with >2-fold risk of CVD death over the subsequent 20 years were combined with during-trial deaths to create 2 new composite outcomes. SI/UC hazard ratios and 95% confidence intervals were estimated for each composite outcome. Of 10 during-trial nonfatal events, 6 were associated (P<0.001) with >2-fold risk of CVD death. A CHD composite outcome (CHD death, myocardial infarction [clinical or serial ECG change], CHF, or coronary artery surgery) was experienced by 520 SI and 602 UC men (SI/UC hazard ratio = 0.86; 95% confidence interval, 0.76–0.97; P=0.01). A CVD composite outcome (CHD [as above], other CVD deaths, stroke, or renal impairment) was experienced by 581 SI and 652 UC men (hazard ratio = 0.89; 95% confidence interval, 0.79–0.99; P=0.04).

Conclusions

In post hoc analyses, composite fatal/nonfatal CHD and CVD rates over 7 years were significantly lower for SI than for UC. These findings reinforce recommendations for improved dietary/lifestyle practices, with pharmacological therapy as needed, to prevent and control major CVD risk factors.

The independent impact of congestive heart failure status and diuretic use on serum uric acid among men with a high cardiovascular risk profile: a prospective longitudinal study

OBJECTIVE

To evaluate the independent impact of congestive heart failure (CHF) status (compensation or decompensation) on serum uric acid levels among men with high cardiovascular risk profile.

METHOD

We analyzed 11,681 men from the Multiple Risk Factor Interventional Trial, using data prospectively collected at baseline and annually over 6 years (64,644 visits). We evaluated the impact of change in CHF status during study follow-up, as compared with study baseline, on hyperuricemia (serum uric acid ≥7 mg/dL) and serum uric acid levels, using generalized estimating equations, adjusting for age, race, weight, weight change, education, alcohol intake, diuretic use, hypertension, serum creatinine level, and dietary factors. Similarly, we evaluated the independent impact of change in diuretic use (initiation or discontinuation).

RESULTS

At baseline, mean serum uric acid was 6.88 mg/dL. Compared with no change in CHF status, odds ratios of hyperuricemia were 1.67 (95% CI, 1.21 to 2.32) for CHF decompensation and 0.21 (95% CI, 0.08 to 0.55) for compensation. The corresponding uric acid differences were 0.41 (95% CI, 0.20 to 0.62) and -1.00 (95% CI, -1.72 to -0.27), respectively. The odds ratios for initiation and discontinuation of diuretic were 3.32 (95% CI, 3.06 to 3.61) and 0.39 (95% CI, 0.35 to 0.44).

CONCLUSIONS

CHF decompensation and diuretic use are both independently associated with increased odds of hyperuricemia among men with a high cardiovascular risk profile, whereas CHF recovery and diuretic discontinuation are associated with substantially lower odds of hyperuricemia.

The serum urate-lowering impact of weight loss among men with a high cardiovascular risk profile: the Multiple Risk Factor Intervention Trial

OBJECTIVES

To evaluate the person-level impact of weight loss on serum urate levels among men with a high cardiovascular risk profile.

METHODS

We analysed 12,379 men (mean serum urate level=407 μmol/l) from the Multiple Risk Factor Intervention Trial, using data prospectively collected at baseline and annually over a 7-year period (78,881 visits). Our endpoint was normouricaemia, defined by serum urate levels≤360 μmol/l, a widely accepted therapeutic target. Person-level effects were estimated using conditional logistic regression models to adjust for time-varying covariates (age, congestive heart failure, hypertension, diuretic use, renal function, alcohol intake and dietary factors).

RESULTS

There was a graded relation between weight loss and achieving normouricaemia (P-value for trend<0.001). Compared with no weight change (-0.9 to 0.9 kg), the multivariate odds ratios of achieving normouricaemia for a weight loss of 1-4.9, 5-9.9 and ≥10 kg were 1.43 (95% CI: 1.33, 1.54), 2.17 (1.95, 2.40) and 3.90 (3.31, 4.61), respectively. The corresponding serum urate level changes were -7, -19 and -37 μmol/l (-0.12, -0.31 and -0.62 mg/dl). Similar levels of associations persisted among subgroups stratified by demographics, presence of gout, hypertension, diuretic use, renal insufficiency, alcohol intake, trial group assignment and adiposity categories (all P-values for trend<0.001).

CONCLUSIONS

Weight reduction could help achieve a widely accepted therapeutic urate target level (≤360 μmol/l) among men with a high cardiovascular risk profile. Although the urate-lowering effect appeared weaker than that of urate-lowering drugs, other associated health benefits would make weight reduction important, particularly in this population.

Smoking and atherosclerotic cardiovascular disease: part II: role of cigarette smoking in cardiovascular disease development

Potential mechanisms and biomarkers of atherosclerosis related to cigarette smoking - a modifiable risk factor for that disease - are discussed in this article. These include smoking-associated inflammatory markers, such as leukocytes, high-sensitivity C-reactive protein, serum amyloid A, ICAM-1 and IL-6. Other reviewed markers are indicative for smoking-related impairment of arterial endothelial function (transcapillary leakage of albumin, inhibition of endogenous nitric oxide synthase activity and reduced endothelium-dependent vasodilation) or point to oxidative stress caused by various chemicals (cholesterol oxidation, autoantibodies to oxidized low-density lipoprotein, plasma levels of malondialdehyde and F(2)-isoprostanes and reduced antioxidant capacity). Smoking enhances platelet aggregability, increases blood viscosity and shifts the pro- and antithrombotic balance towards increased coagulability (e.g., fibrinogen, von Willebrand factor, ICAM-1 and P-selectin). Insulin resistance is higher in smokers compared with nonsmokers, and hemoglobin A1c is dose-dependently elevated, as is homocysteine. Smoke exposure may influence the kinetics of markers with different response to transient or chronic changes in cigarette smoking behavior.

Gout and the risk of type 2 diabetes among men with a high cardiovascular risk profile

OBJECTIVE

Our objective was to evaluate the independent relation between a history of gout and the future risk of type 2 diabetes among men with a high cardiovascular risk profile.

METHODS

We prospectively examined over a 6-yr period the relation between gout and the risk of incident type 2 diabetes in 11 351 male participants from the Multiple Risk Factor Intervention Trial (MRFIT). Incident diabetes was defined based on the American Diabetes Association (ADA) criteria for epidemiological studies. Cox proportional hazards regression was used to adjust for potential confounders.

RESULTS

We documented 1215 new cases of type 2 diabetes. After adjusting for age, BMI, smoking, family history of type 2 diabetes, alcohol intake, dietary factors and presence of individual components of the metabolic syndrome, the multivariate relative risk (RR) for incident type 2 diabetes among men with gout at baseline, as compared with men without gout, was 1.34 (95% CI 1.09, 1.64). When we further adjusted for serum uric acid levels, the association remained significant (RR 1.26; 95% CI 1.02, 1.54). When we updated the status of gout annually during follow-up as a time-varying covariate, the association remained similar. The association also remained similar in our subgroup analyses by major covariates (P-values for interaction >0.16).

CONCLUSIONS

These findings from men with a high cardiovascular risk profile suggest that men with gout are at a higher future risk of type 2 diabetes independent of other known risk factors. These data expand on well-established, cross-sectional associations between hyperuricaemia, gout and the metabolic syndrome, and extend the link to the future risk of type 2 diabetes.

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.

Clinical significance of minor nonspecific ST-segment and T-wave abnormalities in asymptomatic subjects: a systematic review

The purpose of the study is to examine the prevalence and significance of minor nonspecific ST-segment and T-wave abnormalities (NSSTTA) in the prediction of future cardiovascular disease (CVD) events. Minor NSSTTA are commonly encountered in clinical practice. To date, there have been no systematic reviews focusing on the prevalence and prognostic importance of these findings. Literature searches of MEDLINE (1966-2005) were supplemented with searches of bibliographies from key articles. We focused on isolated minor NSSTTA in healthy middle-aged or elderly populations, including men, women, blacks, and whites, and the association of isolated minor NSSTTA with incident cardiovascular and coronary events. Isolated minor NSSTTA are common in middle-aged white men (ranging from 3.6% to 10.3%), and seem to be even more prevalent in women, blacks, and the elderly. In the 3 studies that examined isolated minor NSSTTA, the multivariable-adjusted hazard ratios for coronary mortality ranged from 1.24 to 1.66. Although gender, race, and age-specific differences in the prognostic significance of minor NSSTTA are not clear because of limited data, minor NSSTTA in asymptomatic patients are an important risk factor for coronary and cardiovascular mortality, independent of traditional risk factors. Minor NSSTTA are prevalent in asymptomatic individuals, and they confer increased risk for CVD and coronary heart disease (CHD), independent of traditional risk factors. Future studies with standardized methodology are needed to elucidate the physiological significance of minor NSSTTA and to further describe gender, race, and age-related differences in the prevalence and prognostic significance of minor NSSTTA.

Hyperuricemia and incidence of hypertension among men without metabolic syndrome

The aim of this project was to study the risk of developing hypertension over a 6-year follow-up in normotensive men with baseline hyperuricemia (serum uric acid >7.0 mg/dL) but without diabetes/glucose intolerance or metabolic syndrome. We analyzed the data on men without metabolic syndrome or hypertension at baseline from the Multiple Risk Factor Intervention Trial. These men (n=3073; age: 35 to 57 years) were followed for an average of 6 years by annual examinations. Follow-up blood pressure among those with baseline was consistently higher than among those with normal serum uric acid concentration. We used Cox regression models for adjustment for the effects of serum creatinine, body mass index, age, blood pressure, proteinuria, serum cholesterol and triglycerides, alcohol and tobacco use, risk factor interventions, and use of diuretics. In these models, normotensive men with baseline hyperuricemia had an 80% excess risk for incident hypertension (hazard ratio: 1.81; 95% CI: 1.59 to 2.07) compared with those who did not. Each unit increase in serum uric acid was associated with a 9% increase in the risk for incident hypertension (hazard ratio: 1.09; 95% CI: 1.02 to 1.17). We conclude that the hyperuricemia-hypertension risk relationship is present among normotensive middle-aged men without diabetes/glucose intolerance or metabolic syndrome.

Association of Single Measurements of Dipstick Proteinuria, Estimated Glomerular Filtration Rate, and Hematocrit with 25-Year Incidence of End-Stage Renal Disease in the Multiple Risk Factor Intervention Trial

The incidence of ESRD is increasing rapidly. Limited information exists regarding early markers for the development of ESRD. This study aimed to determine over 25 yr the risk for ESRD associated with proteinuria, estimated GFR (eGFR), and hematocrit in men who did not have identified kidney disease and were randomly assigned into the Multiple Risk Factor Intervention Study (MRFIT). A total of 12,866 men who were at high risk for heart disease were enrolled (1973 to 1975) and followed through 1999. Renal replacement therapy was ascertained by matching identifiers with the United States Renal Data System's data; vital status was from the National Death Index. Men who initiated renal replacement therapy or died as a result of kidney disease were deemed to have developed ESRD. Dipstick urine for proteinuria, eGFR, and hematocrit were related to development of ESRD. During 25 yr, 213 (1.7%) men developed ESRD. Predictors of ESRD were dipstick proteinuria of 1+ or > or =2+ (hazard ratio [HR] 3.1 [95% confidence interval (CI) 1.8 to 5.4] and 15.7 [95% CI 10.3 to 23.9] respectively) and an eGFR of <60 ml/min per 1.73 m(2) (HR 2.4; 95% CI 1.5 to 3.8). Correlation between eGFR and serum creatinine was 0.9; the risk for ESRD with a 1-SD difference of each was identical (HR 1.21). Bivariate analysis demonstrated a 41-fold increase in ESRD risk in those with an eGFR <60 ml/min per 1.73 m(2) and > or =2+ proteinuria (95% CI 15.2 to 71.1). There was no association between hematocrit and ESRD. Other baseline measures that independently predicted ESRD included age, cigarette smoking, BP, low HDL cholesterol, and fasting glucose. Among middle-aged men who were at high risk for cardiovascular disease but had no clinical evidence of cardiovascular disease or significant kidney disease, dipstick proteinuria and an eGFR value <60 ml/min per 1.73 m(2) were strong predictors of long-term development of ESRD. It remains unknown whether intervention for proteinuria or early identification of those with chronic kidney disease reduces the risk for ESRD.

Exclusion and inclusion of nonwhite ethnic minority groups in 72 North American and European cardiovascular cohort studies

BACKGROUND

Cohort studies are recommended for understanding ethnic disparities in cardiovascular disease. Our objective was to review the process for identifying, including, and excluding ethnic minority populations in published cardiovascular cohort studies in Europe and North America.

METHODS AND FINDINGS

We found the literature using Medline (1966-2005), Embase (1980-2001), Cinahl, Web of Science, and citations from references; consultations with colleagues; Internet searches; and RB's personal files. A total of 72 studies were included, 39 starting after 1975. Decision-making on inclusion and exclusion of racial/ethnic groups, the conceptual basis of race/ethnicity, and methods of classification of racial/ethnic groups were rarely explicit. Few publications provided details on the racial/ethnic composition of the study setting or sample, and 39 gave no description. Several studies were located in small towns or in occupational settings, where ethnic minority populations are underrepresented. Studies on general populations usually had too few participants for analysis by race/ethnicity. Eight studies were explicitly on Caucasians/whites, and two excluded ethnic minority groups from the whole or part of the study on the basis of language or birthplace criteria. Ten studies were designed to compare white and nonwhite populations, while five studies focused on one nonwhite racial/ethnic group; all 15 of these were performed in the US.

CONCLUSIONS

There is a shortage of information from cardiovascular cohort studies on racial/ethnic minority populations, although this has recently changed in the US. There is, particularly in Europe, an inequity resulting from a lack of research data in nonwhite populations. Urgent action is now required in Europe to address this disparity.

Special intervention reduces CVD mortality for adherent participants in the multiple risk factor intervention trial

BACKGROUND

Patient adherence affects treatment efficacy, and surprisingly, adherence is frequently associated with reductions in mortality for those receiving placebo.

METHODS

This study considers the role of trial adherence for men (N = 12,338) in the Multiple Risk Factor Intervention Trial (MRFIT), a prospective study of 9-year follow-up mortality following randomization to Special Intervention (SI) or Usual Care (UC). Annual visit attendance rates were used as a measure of adherence.

RESULTS

A significant Adherence x Group Assignment interaction (p =.002) revealed that SI significantly reduced cardiovascular disease (CVD) mortality for highly adherent participants, RR =.91 (95% confidence interval [CI] =.84-.99) but significantly increased CVD mortality for poorly adherent participants, RR = 1.28 (95% CI = 1.05-1.57) when compared to UC. These associations remained after controlling for baseline characteristics (e.g., income), reported illness, or occurrence of a nonfatal CVD event during the trial. The beneficial effect of SI among the adherent participants was partly due to reduced smoking and diastolic blood pressure levels during the trial.

CONCLUSIONS

SI significantly reduced the risk of CVD mortality for participants adherent with the MRFIT, and this effect was accounted for by positive changes in CVD risk factors. These findings suggest a method for evaluating treatment efficacy in subgroups determined by patient responses (e.g., adherence to annual assessment visits) to the treatment program after randomization.

Independent risk for cardiovascular disease predicted by modified continuous score electrocardiographic criteria for 6-year incidence and regression of left ventricular hypertrophy among clinically disease free men: 16-year follow-up for the multiple risk factor intervention trial

Risk prediction for electrocardiographic (ECG) left ventricular hypertrophy related criteria, used in clinical trials, and epidemiologic studies of clinically healthy people, has depended in the past on dichotomous classification of ECG LVH criteria. Recent analyses have shown that more sensitive methods of LVH ECG classification without loss of specificity are needed to improve on dichotomous classification. This was done by relating six year incident significant change in continuous score criteria of ECG LVH to the 16 year (10 year post trial) coronary heart disease (CHD) and cardiovascular disease (CVD) mortality among 12,866 men, free of clinical disease, aged 35 to 57 years at baseline in the Multiple Risk Factor Intervention Trial. It was found that significant change in continuous ECG LVH criteria was a stronger independent predictor of future CHD and CVD mortality than was use of dichotomous classification of the same criteria. It was also demonstrated that increase in continuous ECG LVH indexes, below previous dichotomous thresholds independently (of standard CVD risk factors, including increase in obesity-indicated by an increase in adult BMI) predicted excess CHD and CVD mortality and that combinations of continuous indices increases the specificity and relative risk in clinically disease-free middle-aged men.

Are vacations good for your health? The 9-year mortality experience after the multiple risk factor intervention trial

OBJECTIVE

The objective of this study was to determine the risk for various causes of posttrial death associated with vacation frequency during the Multiple Risk Factor Intervention Trial (MRFIT).

METHODS

Middle-aged men at high risk for coronary heart disease (CHD) were recruited for the MRFIT. As part of the questionnaires administered during the first five annual visits, men were asked whether they had had a vacation during the past year. For trial survivors (N = 12,338), the frequency of these annual vacations during the trial were used in a prospective analysis of posttrial all-cause and cause-specific mortality during the 9-year follow-up period.

RESULTS

The relative risk (RR) associated with more annual vacations during the trial was 0.83 (95% confidence interval [CI], 0.71-0.97) for all-cause mortality during the 9-year follow-up period. For cause of death, the RRs were 0.71 (95% CI, 0.58-0.89) and 0.98 (95% CI, 0.78-1.23) for cardiovascular and noncardiovascular causes, respectively. The RR was 0.68 (95% CI, 0.53-0.88) for CHD (including acute myocardial infarction). These associations remained when statistical adjustments were made for possible confounding variables, including baseline characteristics (eg, income), MRFIT group assignment, and occurrence of a nonfatal cardiovascular event during the trial.

CONCLUSIONS

The frequency of annual vacations by middle-aged men at high risk for CHD is associated with a reduced risk of all-cause mortality and, more specifically, mortality attributed to CHD. Vacationing may be good for your health.

Mortality after 16 years for participants randomized to the Multiple Risk Factor Intervention Trial

BACKGROUND

A mortality follow-up of 12,866 men was conducted 16 years after randomization to special intervention (SI) or usual care (UC) groups of the Multiple Risk Factor Intervention Trial to assess the long-term effect of cardiovascular risk factor intervention on coronary heart disease (CHD), cardiovascular death (CVD), and total mortality.

METHODS AND RESULTS

During the 7-year active-intervention phase of the trial, 6428 of the men were given dietary recommendations to lower blood cholesterol, antihypertensive drugs to lower blood pressure, and counseling for cigarette smoking cessation. The remaining 6438 men were referred to their usual source of medical care. After 16 years, 370 SI and 417 UC men had died from CHD, which represents an 11.4% lower mortality rate for SI versus UC men (95% CI, -23% to 1.9%). Results for total mortality followed a similar pattern; 991 SI and 1050 UC men had died by the end of follow-up (relative difference, -5.7%; 95% CI, -13% to 2.8%). For acute myocardial infarction, a subcategory of CHD, the relative difference was -20.4% (95% CI, -34.4% to -3.4%). Differences between SI and UC men in mortality rates from acute myocardial infarction, CHD, and all causes were greater during the posttrial follow-up period than during the trial.

CONCLUSIONS

Results of a 7-year multifactor intervention program aimed at lowering blood pressure and serum cholesterol and at cigarette smoking cessation among high-risk men give additional evidence of a long-term, continuing mortality benefit from the program.

Serum fatty acids and blood pressure

To examine the relation between serum fatty acids and blood pressure, we conducted a cross-sectional study of 156 men who were enrolled in the Multiple Risk Factor Intervention Trial. After confirming the stability of the stored serum samples, we measured serum fatty acid levels by gas-liquid chromatography and examined their association with blood pressure. Using stepwise linear regression, we determined that each SD increase (1.9%) in the serum level of cholesterol ester palmitoleic acid (16:1) was associated with a systolic pressure increase of 3.3 mm Hg (95% confidence interval, 0.9 to 5.6 mm Hg) and each SD increase (0.1%) in phospholipid omega 9 eicosatrienoic acid (20:3) was associated with a diastolic pressure increase of 1.7 mm Hg (95% confidence interval, 0.5 to 2.9 mm Hg). Serum level of cholesterol ester steric acid (18:0) was inversely associated with diastolic pressure: each SD increase (0.2%) was associated with a decrease of 1.4 mm Hg (95% confidence interval, -2.5 to -0.2 mm Hg). In multivariate models that included dietary fat intake, cholesterol ester dihomogammalinolenic acid (20:3) was also associated with diastolic pressure: each SD increase (0.16%) was associated with an increase of 1.2 mm Hg (95% confidence interval, 0.1 to 2.4 mm Hg). Our results indicate that three nonessential fatty acids--stearic acid, palmitoleic acid, and omega 9 eicosatrienoic acid, and one essential fatty acid--dihomogammalinolenic acid, are independent correlates of blood pressure among middle-aged American men at high risk of coronary heart disease.

Blood pressure and end-stage renal disease in men

BACKGROUND

End-stage renal disease in the United States creates a large burden for both individuals and society as a whole. Efforts to prevent the condition require an understanding of modifiable risk factors.

METHODS

We assessed the development of end-stage renal disease through 1990 in 332,544 men, 35 to 57 years of age, who were screened between 1973 and 1975 for entry into the Multiple Risk Factor Intervention Trial (MRFIT). We used data from the national registry for treated end-stage renal disease of the Health Care Financing Administration and from records on death from renal disease from the National Death Index and the Social Security Administration.

RESULTS

During an average of 16 years of follow-up, 814 subjects either died of end-stage renal disease or were treated for that condition (15.6 cases per 100,000 person-years of observation). A strong, graded relation between both systolic and diastolic blood pressure and end-stage renal disease was identified, independent of associations between the disease and age, race, income, use of medication for diabetes mellitus, history of myocardial infarction, serum cholesterol concentration, and cigarette smoking. As compared with men with an optimal level of blood pressure (systolic pressure < 120 mm Hg and diastolic pressure < 80 mm Hg), the relative risk of end-stage renal disease for those with stage 4 hypertension (systolic pressure > or = 210 mm Hg or diastolic pressure > or = 120 mm Hg) was 22.1 (P < 0.001). These relations were not due to end-stage renal disease that occurred soon after screening and, in the 12,866 screened men who entered the MRFIT study, were not changed by taking into account the base-line serum creatinine concentration and urinary protein excretion. The estimated risk of end-stage renal disease associated with elevations of systolic pressure was greater than that linked with elevations of diastolic pressure when both variables were considered together.

CONCLUSIONS

Elevations of blood pressure are a strong independent risk factor for end-stage renal disease; interventions to prevent the disease need to emphasize the prevention and control of both high-normal and high blood pressure.

Blood pressure and mortality among men with prior myocardial infarction. Multiple Risk Factor Intervention Trial Research Group

BACKGROUND

The purpose of the present study was to describe the relation between blood pressure (systolic [SBP] and diastolic [DBP]) and death from coronary heart disease (CHD) and all causes for men with a history of myocardial infarction (MI).

METHODS AND RESULTS

The study cohort consisted of men aged 35 to 57 years screened for the Multiple Risk Factor Intervention Trial (MRFIT) in 1973 through 1975 and followed for survival for an average of 16 years through 1990. There were 5362 men who reported prior hospitalization for a heart attack of at least 2 weeks' duration at the initial screening of MRFIT. There was a J-shaped relation between SBP and DBP with both CHD and all-cause mortality during the first 2 years of follow-up in older (age, 45 to 57 years) men only. Risk nadirs for SBP were 152 and 145 mm Hg, respectively, for CHD death and all-cause mortality; corresponding DBP risk nadirs were 94 and 90 mm Hg. After the first 2 years, there was a positive association between SBP and death from CHD and all causes. By 15 years, cumulative CHD mortality percentages for men with screening SBP < 120, 120 to 139, 140 to 159, and > or = 160 mm Hg were 19.7%, 21.3%, 27.5%, and 32.0%, respectively. When deaths only after year 2 were considered, although the linear DBP coefficient was significant, the quadratic term for DBP was no longer significant (P > .05). However, the relation still appeared J-shaped as cumulative mortality for those with DBP < 70, 70 to 79, 80 to 89, 90 to 99, and > or = 100 mm Hg was 24.3%, 20.8%, 21.1%, 25.5%, and 29.7%, respectively. When the joint relation of SBP and DBP was considered, there were no survival differences among the four cohorts (SBP > or = 140 and DBP < 80, SBP > or = 140 and DBP > or = 80, SBP < or = 140 and DBP < 80, and SBP < or = 140 and DBP > or = 80) during the first 2 years. After 2 years, both CHD and all-cause mortality rates were approximately 40% higher for participants with SBP > or = 140 mm Hg versus < 140 mm Hg regardless of DBP level (< 80 or > or = 80 mm Hg).

CONCLUSIONS

In this large cohort of men with prior MI, the association of SBP and DBP with CHD and all-cause mortality varied over the 16-year follow-up period. During early follow-up, in older men only, J- or U-shaped relations were evident. However, after 2 years, these same relations had become positive and graded. Given the substantial excess mortality risk in this cohort associated with high blood pressure, particularly SBP, efforts to gradually lower blood pressure should receive high priority among hypertensive men with prior MI.

Serum fatty acids and the risk of stroke

BACKGROUND AND PURPOSE

To examine the relationship between serum fatty acids, which reflect dietary intake, and stroke, we conducted a nested case-control study of 96 men with incident stroke and 96 control subjects matched by age, clinical center, treatment group, and date of randomization who were enrolled in the Multiple Risk Factor Intervention Trial.

METHODS

After confirming the stability of the stored serum samples, we measured serum cholesterol ester and phospholipid fatty acid levels as the percentage of total fatty acids by gas-liquid chromatography and examined their association with incident stroke. Using stepwise conditional logistic regression that controlled for risk factors for stroke, we determined which fatty acids were independent correlates of stroke.

RESULTS

In univariate models, a standard deviation (SD) increase (1.37%) in phospholipid stearic acid (18:0) was associated with a 37% increase in the risk of stroke, whereas an SD increase (0.06%) in phospholipid omega-3 alpha-linolenic acid (18:3) was associated with a 28% decrease in the risk of stroke (all P < .05). Only alpha-linolenic acid in the cholesterol ester fraction was associated with the risk of stroke in multivariate models: an SD increase (0.13%) in the serum level of alpha-linolenic acid was associated with a 37% decrease in the risk of stroke (P < .05). Systolic blood pressure and cigarette smoking were also independently associated with stroke risk.

CONCLUSIONS

Our findings suggest that higher serum levels of the essential fatty acid alpha-linolenic acid are independently associated with a lower risk of stroke in middle-aged men at high risk for cardiovascular disease.

Analysis of the MRFIT screenees: a methodological study

PURPOSE

To review the methods used in the many publications on the MRFIT screenees.

METHOD

Medline was searched for articles mentioning MRFIT screenees. The articles were collected, abstracted, and the method section and some of the result section were scrutinized in detail. The statements in different articles regarding methods used and the presentation of results were compared.

RESULT

The analyses of the MRFIT screenees seem to be retrospective studies of mortality and risk factors, where the underlying data base has been far from complete. Similar data are presented in slightly different fashions in several papers published in different scientific journals at about the same time. The control of the quality of underlying data has been uneven and is not discussed at all in most of the papers published.

CONCLUSION

The often-repeated statement that the MRFIT screenees constitute the largest and most exact data base regarding the relation of risk factors to mortality in the healthy male US population has no foundation.

A re-analysis of caries rates in a preventive trial using Poisson regression models

The analysis of caries incidence in clinical trials has several challenging features: (1) The distribution of the number of caries onsets per patient is skewed, with the majority of patients having few or no cavities; (2) the number of surfaces at risk varies (i) over time and (ii) between patients, due to eruption and exfoliation patterns, dental diseases, and treatments; (3) surfaces within a patient differ in their caries susceptibility, and (4) caries onsets within a patient are correlated due to shared host factors. Recent statistical developments in the area of correlated data analyses permit incorporation of some of these characteristics into the analyses. With Poisson regression models, the expected number of caries onsets can be related to the number of surfaces at risk, the time they have been at risk, and surface- and subject-specific explanatory variables. The parameter estimated in these models is an epidemiological measure of disease occurrence: the disease incidence rate (caries rate) or the rate of change from healthy (sound) to diseased (carious). Differences and ratios of these rates provide standard epidemiological measures of excess risk. To illustrate, Poisson regression models were used for exploratory analyses of the Ylivieska xylitol study.

Risk factors for death from different types of stroke. Multiple Risk Factor Intervention Trial Research Group

The objective of this study was to investigate risk factors for death from different types of stroke among men screened for the Multiple Risk Factor Intervention Trial (MRFIT). A total of 353,340 men were screened by 20 centers for the MRFIT in 1973 to 1975; vital status has been ascertained over an average of 12 years of follow-up (range: 11 to 13 years). Death certificates were coded using the International Classification of Diseases (ICD), ninth revision. Deaths from stroke were classified as death from subarachnoid hemorrhage (ICD code 430), death from intracranial hemorrhage (ICD codes 431 and 432), death from nonhemorrhagic stroke (ICD codes 433 through 438), and death from any type of stroke (ICD codes 430 through 438).

RESULTS

During an average of approximately 12 years of follow-up, 765 deaths from stroke were identified; 139 of these deaths were attributable to subarachnoid hemorrhage; 227, to intracranial hemorrhage; and 399 were classified as nonhemorrhagic stroke. Blood pressure and cigarette smoking were strongly related to each type of stroke. Systolic blood pressure was a stronger predictor than diastolic blood pressure. With the exception of subarachnoid hemorrhage, death rates from each type of stroke increased with age and were higher for black men. The positive association of age and race with subarachnoid hemorrhage was much weaker than for the other types of stroke and was not significant. Income was inversely associated with risk of death from nonhemorrhagic stroke and was not associated with either subarachnoid or intracranial hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

The leukocyte count and risk of lung cancer

The association between leukocyte count and subsequent risk of lung cancer was evaluated in three large cohorts from the United States and Britain. A total of 309 lung cancer events occurred among 28,181 men whose cases were followed-up for 7 to 12 years. In all three cohorts, there was a marked increase in risk of lung cancer with increasing leukocyte count, after adjustment for age and the number of cigarettes smoked per day. The adjusted relative odds in the three cohorts, for a 2000/microliters difference in leukocyte count, were 1.58 (P = 0.0001), 1.29 (P = 0.003) and 1.20 (P = 0.02). These relative odds persisted when current smokers were considered alone, when serum markers of cigarette smoking exposure were adjusted for, and when men with lung cancer events during the first 5 years of follow-up were excluded. The leukocyte count appears to be linked to the pathogenesis of smoking-related lung cancer.

Diuretic induced long term hemodynamic changes in hypertension. A retrospective study in a MRFIT clinical center

Retrospective analysis of hemodynamic factors was performed on hypertensive participants of our Multiple Risk Factor Intervention Trial (MRFIT) center to determine whether these may have a role in the higher mortality in a subgroup of special intervention (SI) participants with minor baseline electrocardiographic abnormalities. Stroke volume was estimated by a formula [SV = K(LVETxPP)x(1 + LVET/DP) where the K factor was determined using a separate group of individuals undergoing cardiac catheterization. The Pearson correlation between the two methods (dye dilution and above formula) was 0.7744 with a 95% confidence interval of 0.57-0.89 for the true correlation. In 222 SI and 186 usual care (UC) participants with no differences in stroke volume index (SVI) and cardiac output index (CI) at baseline, SVI and CI were systematically lower during the entire period of treatment in SI receiving higher average doses of thiazide diuretics. There was a moderate increase of SVI and CI in SI participants toward baseline after hydrochlorothiazide was replaced by other antihypertensive medication in the fourth year of the trial. We conclude that the lower SVI and CI could have been a contributing factor in the higher mortality in the SI group with ECG abnormalities resulting in decreased coronary flow reserve under stress conditions in these participants with probably pre-existing asymptomatic coronary artery disease.

Cigarette smoking and mortality. MRFIT Research Group

METHODS

The relationship of cigarette smoking and smoking cessation to mortality was investigated among men screened for and also among those randomized to the Multiple Risk Factor Intervention Trial (MRFIT).

RESULTS

Among the 361,662 men screened for the MRFIT, cigarette smoking was an important risk factor for all-cause, coronary heart disease (CHD), stroke, and cancer mortality. These risks, on the log relative scale, were strongest for cancers of the lung, mouth, and larynx. The excess risk associated with cigarette smoking was greatest for death from CHD. Overall, approximately one-half of all deaths were associated with cigarette smoking. Among the 12,866 randomized participants, weak positive associations with duration of cigarette smoking habit and tar and nicotine levels were found with all-cause mortality. For both SI and UC men, substantial differences in subsequent CHD (34-49%) and all-cause (35-47%) mortality were evident for men who reported cigarette smoking cessation by the end of the trial compared with those continuing to smoke. There was no evidence that lung cancer death rates were lower among cigarette smokers who quite compared with those who continued to smoke in this 10-year follow-up period.

CONCLUSION

The data are consistent with results of previous epidemiologic studies indicating that the benefits of smoking cessation on CHD are rapid, while for lung cancer, the benefit is not evident in a 10-year follow-up period.

Association between baseline risk factors, cigarette smoking, and CHD mortality after 10.5 years. MRFIT Research Group

METHODS

The association between baseline risk factors and death from coronary heart disease (CHD) after 10.5 years was investigated for cigarette smokers and nonsmokers who entered the Multiple Risk Factor Intervention Trial (MRFIT).

RESULTS

Rates per thousand person-years of CHD mortality were higher for smokers than for nonsmokers at every level of baseline risk factors examined. There were significant associations between CHD mortality and plasma low-density lipoprotein and high-density lipoprotein cholesterol for smokers and nonsmokers. The inverse association between CHD mortality and high-density lipoprotein cholesterol was significantly stronger among nonsmokers compared with that among smokers and was attributable to a very strong association for former smokers. An inverse relationship between CHD and body mass index was evident for smokers and nonsmokers. Rates of CHD death rose sharply when levels of fasting glucose exceeded 140 mg/dl, and there was a significant association between CHD mortality and blood sugar levels for nonsmokers but not for smokers. For both smokers and nonsmokers, an inverse univariate association between alcohol consumption and CHD mortality was evident. This association, however, did not persist after adjustment for plasma high-density lipoprotein cholesterol.

CONCLUSION

Intervention on blood pressure and blood lipids is particularly important among cigarette smokers because of their increased risk of CHD death. The different associations between high-density lipoprotein cholesterol, fasting serum glucose, and CHD mortality for smokers and nonsmokers requires further investigation.

Program on the Surgical Control of the Hyperlipidemias (POSCH): patient entry characteristics. The POSCH Group

The entry characteristics of patients in the Program on the Surgical Control of the Hyperlipidemias (POSCH), a randomized, controlled, clinical trial, are described in this article. The primary objective addressed by POSCH was whether lowering total plasma cholesterol by partial ileal bypass surgery results in a reduction in mortality and morbidity in post-myocardial infarction patients. Between 1975 and 1983, 838 patients between the ages of 30 and 64 years were randomized into POSCH. The mean age at entry was 51 years, and 91% of the patients were men. The mean time between myocardial infarction and entry was 2.2 years. The mean baseline total plasma cholesterol was 251 mg/dl, with a mean LDL-cholesterol of 179 mg/dl and a mean HDL-cholesterol of 40 mg/dl. Significant disease (greater than or equal to 50% occlusion) of one or more major coronary arteries was found in 91% of the patients. In addition to a description of the POSCH patient population at entry, comparisons of the POSCH patient population to populations of participants in other lipid-lowering trials are presented to provide a perspective on how POSCH relates to these trials.

Relationships between weight and caloric intake of men who stop smoking: the Multiple Risk Factor Intervention Trial

Data from 6,569 middle-aged men in the Multiple Risk Factor Intervention Trial were analyzed to determine whether the weight change associated with smoking cessation resulted primarily from appetite or metabolic alterations. The appetite hypothesis attributes weight gain to an enhanced appetite and subsequent increase in caloric intake. The metabolic change hypothesis attributes weight gain to a metabolic alteration and subsequent decrease in basic caloric needs. Caloric intake and weight changes were tabulated for men who quit smoking and were compared to similar changes in men who continued smoking over 12 months. The difference between caloric intake changes in men quitting smoking versus men continuing smoking, controlled for weight change, was attributed to the metabolic change hypothesis. Men who quit smoking consumed 103 calories per day less (95% confidence interval = 29 to 177) than men who continued smoking with similar body weight changes. The decrease in caloric intake attributed to smoking cessation was proportional to the number of cigarettes smoked prior to cessation [corrected].

The relationship of smoking cessation to coronary heart disease and lung cancer in the Multiple Risk Factor Intervention Trial (MRFIT)

The impact of smoking cessation on coronary heart disease (CHD) and lung cancer was assessed after 10.5 years of follow-up in the 12,866 men in the Multiple Risk Factor Intervention Trial (MRFIT). Those men who died of lung cancer (n = 119) were either cigarette smokers at entry or ex-smokers; no lung cancer deaths occurred among the 1,859 men who reported never smoking cigarettes. The risk of lung cancer for smokers, adjusted for selected baseline variables using a Cox proportional hazards model, increased as the number of cigarettes smoked increased (B = 0.0203, SE = 0.0076). There was not the same graded response for CHD among smokers at entry. The risk of CHD death was greater among smokers than nonsmokers (RR = 1.57) (B = -0.0034, S.E. = 0.0048). After one year of cessation, the relative risk of dying of CHD for the quitters as compared to non-quitters (RR = 0.63) was significantly lower even after adjusting for baseline differences and changes in other risk factors. The relative risk for smokers who quit for at least the first three years of the trial was even lower compared to non-quitters (RR = 0.38). However, the relative risk for lung cancer for quitters versus non-quitters was close to 1 both for quitters at 12 months and at three years. These data support the benefits of cessation in relation to CHD and are consistent with other epidemiologic studies which suggest that the lag time for a beneficial effect of smoking cessation on lung cancer may be as long as 20 years.

Stressful life events, Type A behavior, and the prediction of cardiovascular and total mortality over six years. MRFIT Group

The relationship between stressful life events and subsequent mortality and morbidity were determined prospectively over 6 years for 12,866 men participating in the Multiple Risk Factor Intervention Trial (MRFIT). Aslo evaluated was the impact of life events on cardiovascular outcomes for persons exhibiting and not exhibiting coronary prone (Type A) behavior. Subjects completed life events checklists at baseline and each of five annual visits. Participants were also administered the Jenkins Activity Survey measure of Type A behavior at baseline and a subsample of 3110 participants was categorized as to behavior type based on the structured interview assessment method. Cox proportional hazard analyses indicated that number of life events experienced during each of 6 years of follow-up was unrelated to risk in the subsequent year of CHD death or fatal plus nonfatal MI and was inversely related to total mortality. The impact of life events on cardiovascular risk did not differ by behavior type category.

Blood pressure (systolic and diastolic) and risk of fatal coronary heart disease

Among the 356,222 men screened for the Multiple Risk Factor Intervention Trial who had no history of hospitalization for heart attack at entry, more than 2,000 coronary deaths occurred during 6 years of follow-up. With this large data set, detailed cross-tabulations clearly and simply showed the strong graded relation between blood pressure and coronary heart disease death. This risk gradient was evident in each of five age groups ranging from 35 to 57 years and for levels of diastolic blood pressure ranging from less than 75 mm Hg to greater than 115 mm Hg. Systolic blood pressure was more strongly associated with coronary heart disease death than was diastolic blood pressure, and isolated systolic blood pressure elevation was found to be an important risk factor in these middle-aged men. The risk of coronary death was increased among hypertensive men who had elevated serum cholesterol levels or who smoked cigarettes. Because less than 10% of hypertensive men had cholesterol levels in the lowest quintile (below 182 mg/dl) and were nonsmokers, a multi-intervention approach for the large majority of hypertensive persons is clearly indicated. Risks of death were also substantially increased among those hypertensive men who already had end-organ damage, emphasizing the importance of early treatment to prevent such damage. These findings have implications for the design of prevention trials and clinical practice, as it is clear that systolic as well as diastolic blood pressure should be considered in treating hypertensive patients. Additionally, treatment goals should be directed at preventing not only death but many other morbid events, clinical and subclinical, that are associated with elevated blood pressure and that are preventable with appropriate treatment.

Serum cholesterol levels and six-year mortality from stroke in 350,977 men screened for the multiple risk factor intervention trial

We examined the relation between the serum total cholesterol level and the risk of death from stroke during six years of follow-up in 350,977 men, 35 to 57 years of age, who had no history of heart attack and were not currently being treated for diabetes mellitus. The diagnosis of stroke and the type of stroke were obtained from death certificates. Using proportional-hazards regression to control for age, cigarette smoking, diastolic blood pressure, and race or ethnic group, we found that the six-year risk of death from intracranial hemorrhage (International Classification of Diseases, ninth edition [ICD-9], categories 431 and 432) was three times higher in men with serum cholesterol levels under 4.14 mmol per liter (160 mg per deciliter) than in those with higher cholesterol levels (P = 0.05 by omnibus test across five cholesterol levels). On the other hand, a positive association was observed between the serum cholesterol level and death from nonhemorrhagic stroke (P = 0.007). The inverse association of the serum cholesterol level with the risk of death from intracranial hemorrhage was confined to men with diastolic blood pressure greater than or equal to 90 mm Hg, in whom death from intracranial hemorrhage is relatively common. We conclude that there is an inverse relation between the serum cholesterol level and the risk of death from hemorrhagic stroke in middle-aged American men, but that its public health impact is overwhelmed by the positive association of higher serum cholesterol levels with death from nonhemorrhagic stroke and total cardiovascular disease (ICD-9 categories 390 through 459).

Electrocardiographic left ventricular hypertrophy and effects of antihypertensive drug therapy in hypertensive participants in the Multiple Risk Factor Intervention Trial

Data are reported on electrocardiographic left ventricular hypertrophy (ECG LVH) among 8,012 men classified as hypertensive at baseline in the Multiple Risk Factor Intervention Trial. Compared with those allocated to the usual care (UC) control group, men allocated to the special intervention (SI) group experienced a mean reduction of 4 mm Hg in diastolic blood pressure and 7 mm Hg in systolic blood pressure, over 6 years of follow-up. There were 378 new cases of ECG LVH during follow-up; the incidence in the SI group was about 23% less than that in the UC group (4.2 vs 5.4% 2P less than 0.01). Among the 189 men with ECG LVH at baseline, those in the SI group experienced about 24% more annual follow-up visits at which they were free of ECG LVH (4.6 vs 3.7 visits; 2P less than 0.01). This reduced incidence and increased reversal of ECG LVH in the SI group compared with that in the UC group was consistent with significant overall reductions (2P less than 0.001) among SI men in mean wave amplitude in those leads in which voltage is correlated with left ventricular mass (T wave in V1, R wave in aVL and S wave in V3). In SI and UC groups combined, the presence of ECG LVH either at baseline or at follow-up was associated with several-fold increases in death from cardiovascular diseases in general, and death from coronary artery disease in particular.(ABSTRACT TRUNCATED AT 250 WORDS)

Recruitment of participants for the multiple risk factor intervention trial (MRFIT)

The Multiple Risk Factor Intervention Trial (MRFIT) was a randomized primary prevention trial designed to test the effect of multifactor intervention on mortality from coronary heart disease. Before randomization, men were seen at three screening visits to establish eligibility. A total of 361,662 men were screened, and 12,866 men were randomized, 866 more than the goal of 12,000. The total time required for planning and recruitment was 44 months. Eligibility rates and dropout or refusal rates between screening visits varied considerably among the 20 clinics that took part in MRFIT. The variation in eligibility rates resulted largely from subjective interpretation by the staff of the willingness of the men to participate in the study and to make risk factor changes. Cigarette smokers and blacks were more likely to discontinue their participation between screening exams. The ultimate success of the MRFIT recruitment is attributed to (1) the previous experience of investigators in screening large numbers of participants for clinical trials and similar epidemiologic investigations, (2) the identification at each clinic of one or more persons whose specific responsibility was recruitment, (3) the phased entry of clinics into the study, (4) routine monitoring and reporting of recruitment rates by the coordinating center, (5) regular discussion of recruitment successes and problems at the Steering Committee meetings, and (6) site visits to examine in detail recruitment problems.

Usefulness of sex steroid hormone levels in predicting coronary artery disease in men

The relation between sex hormone levels and subsequent risk of a major coronary event was studied in a nested case-control study among 163 men in the Multiple Risk Factor Intervention Trial who later had a major coronary event and in 163 controls. Cases and controls were matched for age, serum cholesterol level, randomization group, randomization date and clinic. Blood samples were collected at baseline before randomization and frozen at -70 degrees C. Follow-up extended over 6 to 8 years. Sixty-one patients had a nonfatal acute myocardial infarction and 102 fatal infarction. Total and free testosterone, total and free estradiol, androstenedione and estrone concentrations were measured. There were no significant differences between cases and controls for any sex hormone level. There was also no difference in the ratio of testosterone to estradiol. Controlling for other cardiovascular risk factors did not change these results. These results do not support previous case-control studies of a relation between sex hormone levels and risk of heart attack among men.

Changing coronary heart disease risk-factor status: the effects of three behavioral programs

Seventy-five persons (57 male and 18 female) with a high risk of coronary heart disease (CHD) were randomly assigned in equal numbers to three 8-week behavioral treatment programs. All three treatments were designed to alter simultaneously a number of risk-elevating behavior patterns, in the expectation that change in any one behavior pattern would reinforce change in others. Weight, blood pressure, and aerobic fitness were regularly assessed in all subjects. Serum lipids were also measured, but less frequently. All three interventions produced significant beneficial changes in the major objective measures, and the changes were well maintained after 12 months. The most improved group exhibited the following mean changes: weight loss of 9.2 kg, reductions in blood pressure of 12.9/8.8 mm Hg, improvement in aerobic capacity of 33%, reduction in serum cholesterol of 0.45 mmol/liter, and reduction in current overall CHD risk of 41%. The effectiveness of the interventions was positively related to the degree to which the programs emphasized training in, and detailed application of, behavioral change principles.

Overall and coronary heart disease mortality rates in relation to major risk factors in 325,348 men screened for the MRFIT. Multiple Risk Factor Intervention Trial

The influence of risk factors on CHD and all-cause mortality rates in 35- to 57-year-old men is examined by means of data on 325,348 white men who were screened for the MRFIT. This large data set permits an unusually detailed analysis of factors associated with the 6968 deaths, including 2426 ascribed to CHD, that were detected in the Social Security Administration data set during 6 years of follow-up. Simple cross classification of the data confirms the independent effect of serum cholesterol concentration, diastolic blood pressure, and cigarette smoking as risk factors for CHD and all-cause mortality rates. A distinct escalation of risk is noted for combinations of these risk factors. The strength of the association of each of the risk factors with CHD and all-cause mortality rates diminished with increasing age, although the number of excess deaths attributable to the risk factors increased because of the higher death rates in older men. Comparison of these findings with those observed in the five populations studied in the Pooling Project revealed an overall similarity in the risk relationships. It is estimated that elimination of these risk factors has the potential for reducing the CHD mortality rate by two thirds in 35- to 45-year old men, and by one half in 46- to 57-year-old men.

Coronary heart disease death, nonfatal acute myocardial infarction and other clinical outcomes in the Multiple Risk Factor Intervention Trial. Multiple Risk Factor Intervention Trial Research Group

The Multiple Risk Factor Intervention Trial was a randomized clinical study to test whether a special-intervention (SI) program aimed at reducing serum cholesterol levels, blood pressure and cigarette smoking would prevent coronary heart disease (CHD) in middle-aged men. The main endpoint reported here is the percentage of participants experiencing first major CHD events (either nonfatal acute myocardial infarction [AMI] or CHD death) during 7 years of follow-up. This outcome was slightly less frequent in the 6,428 SI men than in the 6,438 men assigned to their usual source of care (UC). However, the relative difference--either 1% (95% confidence interval -17% to 16%) or 8% (95% confidence interval -5% to 20%), depending on how AMI was classified--was not statistically significant. Regression analyses within the SI and UC groups suggested that the cholesterol and cigarette smoking interventions reduced the number of first major CHD events: the associations between lowering the levels of these 2 factors and reductions in CHD rates were significant (p less than 0.001) and of the anticipated magnitude. A similar analysis of antihypertensive treatment in the SI group revealed no favorable association between lowering blood pressure and CHD rate, and other subgroup comparisons suggested that a mixture of beneficial and adverse effects may underlie this finding. Thus, the nonsignificant overall UC/SI contrast in CHD rates may reflect a combination of the expected beneficial effects of the cholesterol and smoking interventions with unexpected heterogeneous effects of the antihypertensive intervention. Seven of 8 other prespecified cardiovascular endpoints occurred less frequently among SI than among UC men, the difference being nominally significant (p less than 0.05) for angina pectoris, congestive heart failure and peripheral arterial disease.