Epidemiologic assessment of the role of blood pressure in stroke: the Framingham Study. 1970.

Control of hypertension, labile or fixed, systolic or diastolic, at any age, in either sex appears to be central to prevention of atherothrombotic brain infarction (ABI). Prospectively, hypertension proved the most common and potent precursor of ABI's. Its contribution was direct and could not be attributed to factors related both to stroke and hypertension. Asymptomatic, causal "hypertension" was associated with a risk of ABI about four times that of normotensives. The probability of occurrence of an ABI was predicted no better with both blood pressure measurements or the mean arterial pressure than with systolic alone. Since there was no diminishing impact of systolic pressure with advancing age, the concept that systolic elevations are, even in the aged, innocuous is premature. Comparing normotensives and hypertensives in each sex, women did not tolerate hypertension better than men.

Monitoring accountability of a clinical nutrition service.

The first step in the effort to establish a stronger link between nutrition care intervention and health status is to identify actual services provided. This study examined the accountability of a clinical dietetic staff by using an explicit procedure that made it possible for performance to be measured. Data were gathered at an urban teaching hospital to determine the nutrition care provided as compared with stated standards. Using the Policy and Procedure Manual as the written standard, the authors analyzed data from medical record audit, time utilization studies, staff interviews, and monthly reports. The level of accountability was very high, with less than 1 discrepancy in 10, for all the data collected. The dietetic staff members at the hospital verified the attainment of established standards by clearly and specifically documenting their services. It would appear that a decision about priorities and responsibilities had been made that was well supported by staff and institution. The establishment of a nutrition care team, in which clinical dietitians assumed a supervisory role that promoted and supported delegation to dietetic technicians and dietetic assistants, also contributed to good performance.

Hearing loss in the elderly: an epidemiologic study of the Framingham Heart Study Cohort.

This study used epidemiologic methods to examine hearing loss in the elderly. The Framingham Heart Study Cohort was the reference population. The participants were 935 men and 1358 women, aged 57 to 89 years. Using a conservative definition of hearing loss as threshold levels greater than 20 dB above audiometric zero for at least one frequency from 0.5 to 4 kHz, the prevalence was estimated to be 83%. The majority of cases displayed a sensorineural hearing loss. There were no statistically significant differences by sex at 1 kHz and below. Women had significantly better hearing than men at 2 kHz and above. A multivariate model was constructed to determine which variables had a significant impact upon hearing loss. Under the model, age, sex, illness, family history of hearing loss, Meniere's disease, and noise exposure were significant population risk factors. Age was by far the most critical risk factor.

Clinical-electrocardiographic correlates of newly acquired left bundle branch block: the Framingham Study.

To determine whether any associated electrocardiographic findings in persons with newly acquired complete left bundle branch block (LBBB) correlate with the prevalence of associated clinically apparent cardiovascular abnormalities, electrocardiograms (ECGs) from all 55 members of the Framingham Study cohort in whom LBBB developed during 18 years of routine prospective biennial examinations were reviewed. A QRS axis left of or equal to 0 degrees, left atrial conduction delay and an inverted T wave in lead V6 on the first ECG with LBBB, and an abnormal ECG in the Framingham examination preceding the appearance of LBBB each correlated with the prevalence of systemic hypertension, cardiomegaly, coronary heart disease and congestive heart failure. However, neither the PR interval nor the duration of the QRS complex on the first ECG with LBBB correlated with the prevalence of any of the associated cardiovascular abnormalities. The 8 patients with neither left atrial conduction delay nor a QRS axis left of or equal to 0 degrees on the first Framingham ECG with LBBB nor an abnormal ECG on the examination preceding the appearance of LBBB were 6 times more likely to remain free of all of the clinical cardiovascular abnormalities than the 47 patients with 1 or more of these 3 electrocardiographic findings (p less than 0.001).

The association between cholesterol cholelithiasis and coronary heart disease in Framingham, Massachusetts.

A relationship between cholesterol gallstone disease and atherosclerosis or its sequellae has long been postulated but has never been adequately proven. Data for this investigation of the relationship of diagnosed cholesterol cholelithiasis to subsequent incident coronary heart disease were obtained from a review of the pre-existing prospectively collected medical records of the 5,209 individuals followed since 1952 as members of the original cohort of the Framingham Heart Study. Preliminary univariate examination of these data, making no correction for time ordering of the conditions or for shared risk factors, indicated a significant modest positive association in men but no relationship in women. Logistic multiple regression analyses, allowing for the effects of time ordering and for eight standard coronary disease risk factors, confirmed these findings. The authors speculate that the presence of cholesterol gallstones in male patients may be indicative of an unfavorable lipoprotein profile. These results have clinical implications in that male gallstone patients are at increased risk for subsequent coronary disease and should be monitored accordingly. This investigation marks the first time that a relationship between these conditions has been established using a longitudinal cohort study approach.

Validity of serum total cholesterol level obtained within 24 hours of acute myocardial infarction.

The relation of a serum cholesterol level obtained during acute myocardial infarction (AMI) to the patient's usual baseline level is unclear. Many physicians tend to ignore cholesterol levels measured during AMI and will wait several months before obtaining a repeat cholesterol measurement; in many instances this delays interventional programs. Using the Framingham study cohort of patients, the records of all persons sustaining AMI were reviewed. Eighty-three patients were identified who had total cholesterol (TC) levels recorded within 2 years of AMI, within 24 hours of hospitalization for AMI and within 2 years after hospital discharge. In these persons, there was no statistically significant difference in the TC values measured at these 3 times. Thus, TC levels drawn within the first 24 hours of AMI accurately reflect a baseline level and can be used in instituting intervention programs.

Subarachnoid and intracerebral hemorrhage: natural history, prognosis, and precursive factors in the Framingham Study.

No uniformly accepted hypothesis explains the genesis and rupture of intracranial aneurysms. We followed 5,184 men and women prospectively for 26 years; 36 cases of aneurysmal subarachnoid hemorrhage (SAH) accounted for 62% of all intracranial hemorrhages. Blood pressure before SAH was higher in these patients than in controls. Definite hypertension (greater than or equal to 160 mm Hg and/or greater than or equal to 95 mm Hg) at entry to the study or at closest exam before SAH was more frequent than in controls. Cigarette smoking, particularly heavy smoking, was also more frequent among cases.

Duration of atrial fibrillation and imminence of stroke: the Framingham study.

The role of Atrial Fibrillation (AF) as a precursor of stroke was examined in the Framingham cohort based on 30 years of follow-up during which time 501 strokes occurred. There were 59 persons who sustained stroke in association with AF excluding those with rheumatic heart disease. AF increased the risk of stroke five-fold and the excess risk was found to be independent of the frequently associated cardiac failure and coronary heart disease. The contribution of AF to stroke risk was also at least as powerful as that of the other cardiovascular precursors. Stroke associated with AF was not only independent and substantial but also imminent. There was a distinct clustering of stroke events at the time of onset of the AF. Thirty day case-fatality rates were no different in those with strokes accompanied by AF than not at 17% versus 19% respectively. Recurrences in those with AF were only slightly more frequent, 25% versus 20%, a difference that was not statistically significant. Stroke recurrence in the first 6 months following initial stroke was more than twice as common (47% versus 20%) in the AF group.

Risk factors for pulmonary embolism. The Framingham Study.

To assess potential long-term risk factors for major pulmonary embolism, 46 subjects from the Framingham Heart Study with autopsy-confirmed and clinically significant pulmonary embolism were identified in whom age, systolic blood pressure, cholesterol level, cigarette use, glucose level, Metropolitan relative weight, and varicose veins were ascertained at entry into the Study. These variables were compared among these 46 subjects, all 3,470 subjects in whom these variables were measured at the inception of the Study, and the 998 of these subjects who died within 26 years of follow-up. In multivariate analysis of subjects with autopsy-confirmed major pulmonary embolism and all subjects who died, only Metropolitan relative weight was significantly and independently associated with pulmonary embolism and only among women (p less than 0.001). These findings indicate that, in this cohort, increased adiposity in women is an important long-term factor for significant pulmonary embolism at autopsy. This raises the possibility that weight reduction in obese women may decrease the chances of pulmonary embolism.

Obesity as an independent risk factor for cardiovascular disease: a 26-year follow-up of participants in the Framingham Heart Study.

The relationship between the degree of obesity and the incidence of cardiovascular disease (CVD) was reexamined in the 5209 men and women of the original Framingham cohort. Recent observations of disease occurrence over 26 years indicate that obesity, measured by Metropolitan Relative Weight, was a significant independent predictor of CVD, particularly among women. Multiple logistic regression analyses showed that Metropolitan Relative Weight, or percentage of desirable weight, on initial examination predicted 26-year incidence of coronary disease (both angina and coronary disease other than angina), coronary death and congestive heart failure in men independent of age, cholesterol, systolic blood pressure, cigarettes, left ventricular hypertrophy and glucose intolerance. Relative weight in women was also positively and independently associated with coronary disease, stroke, congestive failure, and coronary and CVD death. These data further show that weight gain after the young adult years conveyed an increased risk of CVD in both sexes that could not be attributed either to the initial weight or the levels of the risk factors that may have resulted from weight gain. Intervention in obesity, in addition to the well established risk factors, appears to be an advisable goal in the primary prevention of CVD.

Association of hyperestrogenemia and coronary heart disease in men in the Framingham cohort.

The serum levels of estradiol and testosterone as well as established risk factors for coronary heart disease were estimated in 61 men (mean age 70.0 +/- 6.4 [SD] years) with coronary heart disease and in 61 matched control subjects enrolled in the Framingham Heart Study. The mean serum estradiol level was significantly higher in the subjects with coronary disease (p = 0.011). This difference in estradiol level increased with the exclusion of subjects older than 75 years (p less than 0.001). The mean serum testosterone level was not significantly different. None of the established risk factors for coronary heart disease was different between subjects with coronary disease and control subjects except blood glucose level, which was higher in the subjects with coronary disease (p = 0.025). We conclude that hyperestrogenemia is an important correlate of coronary heart disease in men.

Prevalence of submitral (anular) calcium and its correlates in a general population-based sample (the Framingham Study).

To obtain epidemiologic information on submitral calcium, 2,069 subjects in the original Framingham Study cohort (mean age 70 +/- 7 years) and 3,625 of the offspring of the cohort and their spouses (mean age 44 +/- 10 years) with adequate echocardiograms were evaluated. Submitral calcium was detected in 162 (2.8%) of the 5,694 subjects; greater than 90% of the subjects with such calcium came from the 40% of the study group greater than 59 years of age. Women were more than twice as likely to have such calcium as men. Age in both sexes, systolic blood pressure in men, and obesity in women were significantly and independently associated with submitral calcium. There was a 12-fold excess of atrial fibrillation in subjects with (20 of 162, 12%) compared with those without (53 of 5,532, 1%) submitral calcium.

Summary estimates of cholesterol used to predict coronary heart disease.

The relationships of total cholesterol and the proportion of cholesterol in individual lipoprotein classes to coronary heart disease are complex. To help simplify these relationships, cholesterol values are often combined into one summary estimate to form a single risk factor with a relationship to disease that is more easily described. Although summary estimates result in convenient expressions relating cholesterols to coronary heart disease, there is the potential for sacrificing information by ignoring the joint configuration of cholesterols that make up these estimates. We investigated the extent of this possibility for the ratio of total cholesterol to high-density lipoprotein cholesterol and the ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol. The findings suggest that the summary estimates are useful expressions for combining cholesterol information and are strong predictors of coronary heart disease. Clinicians who choose to use a summary estimate for screening purposes should recognize that a single ratio estimate is not always as informative as the joint configuration of the cholesterols that make up the estimate. This possibility is most clearly exhibited for the ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol, and it may become more apparent in future studies as the capabilities of exploring lipoprotein cholesterol relationships improve.

Cigarette smoking as a confounder of the relationship between relative weight and long-term mortality. The Framingham Heart Study.

Cigarette smoking is a potential confounder of the relationship between obesity and mortality, and statistical control for this factor requires careful consideration. Framingham Heart Study subjects were weighed, their stature measured, and cigarette smoking histories obtained at the first biennial examination starting in 1949. Of men under desirable weight (Metropolitan relative weight [MRW], less than 100%), more than 80% were smokers, while only about 55% of the extremely overweight men were cigarette smokers. When age-, smoking-, and MRW-specific mortalities for 26 years of follow-up were calculated in these men, it was found that smokers had higher mortality than nonsmokers but that in the smokers and nonsmokers, minimum mortalities occurred for subjects who were initially in the "desirable weight" group (MRW, 100% to 109%). Among cigarette smokers, lean men (MRW, less than 100%) experienced considerably elevated mortality, often higher than that in all but the most overweight cigarette smokers. These findings suggest that elevated mortality in low-weight American men results from the mortality risks associated with cigarette smoking and demonstrates the need for controlling for cigarette smoking when considering the relationship between relative weight and mortality. Furthermore, the concept of "desirable weight" developed by the Metropolitan Life Insurance Co in 1959 and subsequently distributed in tabular form is validated by this long-term study. Thus, even those men who were near the average weight (about 20% above "desirable weight") showed appreciably elevated mortality. This finding is contrary to the widely held view that moderate overweight carries no increased risk.

Accuracy of death certification of stroke: the Framingham Study.

The validity of death certification of stroke was studied in the general population cohort at Framingham, MA. During the last 30 years, 5106 people aged 30 to 62 and free of CHD and stroke at entry have been followed for the development of cardiovascular disease including stroke. Of the 280 decedents with certified stroke 113 (40% false negative rate) had no mention of stroke on the death certificate. THe false negative rate increased significantly with increasing age at death and increasing interval from last stroke to death. Among the 216 certificates listing stroke there were 46 false positives (21%). Analysis by type of stroke disclosed marked over-reporting of cerebral hemorrhage and under-reporting of cerebral embolus. This comparison of prospectively collected data to death certificates should raise questions about the accuracy of studies dependent on ths source of information.

Lack of association between HLA and age in an aging population.

In a sample of 228 Framingham Study participants aged 58 to 86 who were typed for HLA, neither frequencies of individual antigens nor heterozygosity at the A or B loci appeared to be related to age. Previously found associations could be chance occurrences, or HLA-related effects on longevity in the general population might be small. It is also possible that such effects occur at younger ages than those included in our study or that HLA is related to the aging process in a way that is detectable only at very advanced ages.

Survival and recurrence following stroke. The Framingham study.

Survival and recurrences after stroke were assessed prospectively in a general population sample of 5184 subjects followed biennially for 26 years. Initial strokes occurred in 198 men and 196 women. There were 84 second and 27 third strokes and 223 deaths reported. Thirty day case-fatality rates for initial strokes were: 15% (33/222) for brain infarction, 16% (10/63) for cerebral embolus, 46% (18/39) for subarachnoid hemorrhage, and 82% (14/17) for intracerebral hemorrhage. Cumulative, age-adjusted 5 year survival rates for brain infarction were reduced by pre-stroke cardiac disease (coronary heart disease and/or congestive heart failure) and hypertension prior to initial stroke from .85 to .35 in men and .70 and .56 in women. Hypertension alone reduced survival from .85 to .51 in men, but not in women. Recurrences were primarily of the same type as the initial stroke. Cumulative 5 year recurrence rate for brain infarction was .42 for men, almost double that for women. Rates were reduced by excluding hypertensives and those with combined cardiac comorbidity and hypertension. Thus, risk of death or recurrence after stroke is substantial and profoundly influenced by sex and by cardiac comorbidity and hypertension present prior to the initial event.

Epidemiologic features of chronic atrial fibrillation: the Framingham study.

In the Framingham Study 2325 men and 2866 women 30 to 62 years old at entry were followed biennially over 22 years for the development of chronic atrial fibrillation in relation to antecedent cardiovascular disease and risk factors. During surveillance, atrial fibrillation developed in 49 men and 49 women. The incidence rose sharply with age but did not differ significantly between the sexes. Overall, there was a 2.0 per cent chance that the disorder would develop in two decades. Atrial fibrillation usually followed the development of overt cardiovascular disease. Only 18 men and 12 women (31 per cent) had chronic atrial fibrillation in the absence of cardiovascular disease. Cardiac failure and rheumatic heart disease were the most powerful predictive precursors, with relative risks in excess of sixfold. Hypertensive cardiovascular disease was the most common antecedent disease, largely because of its frequency in the general population. Among the risk factors for cardiovascular disease, diabetes and electrocardiographic evidence of left ventricular hypertrophy were related to the occurrence of atrial fibrillation. The development of chronic atrial fibrillation was associated with a doubling of overall mortality and of mortality from cardiovascular disease.