PubMed Health⌕ Search

Biomedical subjects

A R Sharrett

Publications and source records attributed to A R Sharrett.

At least 73 records · Page 4Linked to original sources
PubMed1992

The relation of high density lipoprotein cholesterol and its subfractions to apolipoprotein A-I and fasting triglycerides: the role of environmental factors. The Atherosclerosis Risk in Communities (ARIC) Study.

Cross-sectional analysis of four general representative populations of middle-aged adults in the United States in 1986-1989 provides estimates of the close relation of high density lipoprotein cholesterol (HDL cholesterol) to its major structural apolipoprotein (apolipoprotein A-I) and to fasting plasma triglyceride levels. HDL cholesterol differences of approximately 0.4 mg were associated with 1-mg differences in apolipoprotein A-I; differences of 20% in HDL cholesterol (reductions) were associated with triglyceride doublings. Variation in apolipoprotein A-I and triglyceride concentration together accounted for 66% of the population variance in HDL cholesterol. The uniformity of this pattern in the four race-sex groups studied suggests an important role of triglyceride-cholesterol transfer as a determinant of HDL cholesterol. The fundamental relations observed among HDL cholesterol, apolipoprotein A-I, and triglycerides were unaltered by levels of factors under personal volition. The volitional factors appeared to influence HDL cholesterol indirectly: Obesity and physical activity were affected primarily through their associations with triglycerides, and alcohol use and smoking through associations with apolipoprotein A-I. The association of alcohol use with elevated HDL cholesterol was attenuated in persons with greater body mass.

Aged↗
PubMed1992

The Atherosclerosis Risk in Communities (ARIC) Study. Introduction and objectives of the hemostasis component.

The Atherosclerosis Risk in Communities (ARIC) Study is an observational epidemiologic study conducted in four communities. ARIC has two major components: One records the occurrence of myocardial infarction resulting in hospitalization and coronary heart disease death in adults aged 35 to 74 living in the communities; the other is a prospective study of representative cohorts aged 45 to 64. Measurement of hemostatic factors is part of the cohort study, whose major objectives include investigating etiologic factors associated with atherosclerosis and its clinical outcomes. Arterial intimal-medial wall thickness, an index of early atherosclerosis, is measured precisely from ultrasound images of carotid and popliteal arteries. Participants (n = 15,801) completed their first examination, which included measurements of factors associated with coagulation (fibrinogen, factor VII, factor VIII, and von Willebrand factor) and coagulation inhibition (protein C and antithrombin III). Measures of coagulation activation, platelet activation, and fibrinolytic activity will be performed on stored plasma from selected case patients and control subjects.

Adult↗
PubMed1991

Carotid atherosclerosis measured by B-mode ultrasound in populations: associations with cardiovascular risk factors in the ARIC study.

To assess whether carotid atherosclerosis measured by B-mode ultrasound is related to cardiovascular risk factors, 386 cases with carotid artery wall thickening and an equal number of controls free of arterial intima-media thickening were drawn from the cohort of the Atherosclerosis Risk in Communities (ARIC) Study examined in four communities in the United States between 1988 and 1990. Cases and controls were individually matched on sex, race, age group, study center, and date of examination. The mean values of total cholesterol, low density lipoprotein (LDL) cholesterol, total triglyceride, blood pressure, and pack-years of cigarette smoking were higher in cases than controls. Mean high density lipoprotein (HDL) cholesterol was lower in cases than controls. Case-control differences were all statistically significant. Multivariable-adjusted odds ratios point to differences of considerable magnitude in the risk of carotid atherosclerosis between groups defined by clinical and public health-oriented risk factor cut-points.

Arteriosclerosis↗
PubMed1991

Use of sonography to evaluate carotid atherosclerosis in the elderly. The Cardiovascular Health Study. CHS Collaborative Research Group.

Carotid sonography is being performed on more than 5,000 participants in the Cardiovascular Health Study, a prospective, multicenter study of cardiovascular disease in men and women aged 65 years and older. The sonographic methods used to examine and measure the extracranial carotid arteries are described. Initial validation studies were performed on 61 subjects with a mean age of 68.6 years. Analysis of within- and between-sonographer differences and between-reader differences were performed for selected variables. In general, the mean absolute differences for within- and between-sonographer comparisons were small, with even less variability between readers. Variability was less for the common carotid artery than for the internal carotid artery. These data suggest that carotid sonography is a reliable and reproducible method for use in the study of carotid atherosclerosis in population studies.

Age Factors↗
PubMed1990

Effect of blood collection and processing on radioimmunoassay results for apolipoprotein B in plasma.

We studied the effects of different blood collection and processing procedures on quantification of apolipoprotein (apo) B by radioimmunoassay. High-density lipoprotein subfractions HDL3 and HDL2 and isolated apoA-I did not cross-react in the assay. Analytical recovery of apoB at different doses of very-low- and low-density lipoproteins were complete. Inter- and intra-assay coefficients of variation (CVs) averaged 7.4% and 6.0%, respectively. Blood from 20 subjects was collected into tubes containing EDTA alone or EDTA with antiproteolytic and antioxidant agents; one half of each plasma was separated immediately, half after 3 h at 4 degrees C. Regardless of the addition of protective agents or the time difference in separating plasma from other blood elements, freezing plasma at -70 degrees C decreased apoB content a similar amount, an average of 6.8%. This loss of apoB immunoreactivity was not related to apoB content in fresh plasma. Analysis of variance showed no differential effect on apoB content by the various additions to whole blood or plasma. No additional apoB content was lost in once-frozen aliquots of three human plasma pools during storage at -70 degrees C for up to 18 months. We conclude that concentrations of apoB in human plasma can be measured reliably after long-term storage, although the absolute value may decrease slightly as a result of freezing.

Analysis of Variance↗
PubMed1985

Drinking water source and mortality in US cities.

An apparent excess risk of all-cancer mortality among 473 of the largest US cities was found in relation to surface drinking water supplies. The increased risk for 100% surface water versus 100% ground water use was slight, about 2%, but statistically significant. This finding agrees with reports from several earlier studies in smaller geographical regions of the US, Great Britain and Canada. A relationship was further supported by the replication of this association within the larger of the 11 independent regions studied. Our data suggest that the association with surface water may be specific to cancer mortality. The increased risk would be expected to be greater than 2% if analyses were restricted to cancers of sites previously related to the use of surface drinking water.

Carcinogens, Environmental↗
PubMed1984

Trace metals in drinking water: lack of influence on blood pressure.

It has been suggested that certain trace metals may affect human blood pressure. We recently measured trace metals in the tapwater from the homes of 246 male participants of the Normative Aging Study. Participants were free of any disease or medication known to influence blood pressure. No statistically significant relationship was found between lead concentration and systolic blood pressure in an analysis of covariance, controlling for age and body mass index. Diastolic pressure was examined as well and the results were almost identical. Since educational level and town of residence were potential confounders, we stratified on these variables but no association between lead concentration and blood pressure emerged. Similarly, no statistically significant relationships were found between blood pressure and copper or iron. Blood pressure did differ significantly among zinc concentration groups but no uniform trend appeared. In light of evidence from other studies suggesting that blood pressure is influenced by lead or other elements in drinking water, further investigations with more highly exposed subjects or a prospective design appear warranted.

Adult↗
PubMed1978

Clinical healing two to six years after poststreptococcal glomerulonephritis in Trinidad.

To determine the incidence of chronic nephritis after poststreptococcal acute glomerulonephritis in Trinidad, 760 patients (41 adult) were examined two to six years after recovery from the illness, 344 being studied twice (four and six years). Only 1.8 per cent had persistent urine abnormalities on their last follow-up examination, and another 8.0 per cent had abnormalities that were transient or occurred only after the patient had assumed the lordotic position. In 1.4 per cent hypertension was present, whereas only one had azotemia. Both persistent urine abnormalities and hypertension increased in prevalence with age at onset of prior poststreptococcal glomerulonephritis but did not vary between sexes, races or epidemic versus endemic forms. Half the urine abnormalities present four years after recovery were absent two years later. Thus, poststreptococcal acute glomerulonephritis appears to have a low incidence of chronicity in Trinidad, with continuing resolution for more than four years.

Acute Disease↗
PubMed1978

Trends in urban mortality in relation to fluoridation status.

Mortality trends from 1950 to 1970 were studied for 473 cities in the United States with populations of 25,000 or more in 1950, according to fluoridation status of their water supplies. Findings showed no relationship between fluoridation and observed changes in general mortality over the 20-year period. Also, no relationship was found between fluoridation and heart or cancer death rate trends.

Fluoridation↗
PubMed1977

Water hardness and cardiovascular disease. Elements in water and human tissues.

The hypothesis that the hardness of drinking water has a causal role in the development of cardiovascular disease will be strengthened if it can be demonstrated that elements in drinking water find their way into human tissues in significant amounts. For biologically important metals, the evidence is reviewed for a relationship of tissue levels to levels in drinking water. Hard water can contribute significantly to daily magnesium intake. Residents of hard-water areas may have raised levels of magnesium in coronary arteries, bone, and myocardial tissue. Lead levels in bone and in blood have been shown to be elevated in individuals living in homes with lead plumbing and soft water. Cadmium intake from water is probably small compared to that from other sources, and there is no convincing evidence of alteration in human tissue levels via drinking water cadmium. Human zinc and copper tissue levels are of interest but have not been adequately studied in relation to drinking water levels.

Bone and Bones↗