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Biomedical subjects

D S Sharp

Publications and source records attributed to D S Sharp.

At least 73 records · Page 4Linked to original sources
PubMed1995

Distribution and correlates of insulin in elderly men. The Honolulu Heart Program.

The role of insulin in cardiovascular disease is uncertain, and studies in elderly or minority populations are infrequent. Fasting and 2-hour insulin concentrations and their cross-sectional associations with cardiovascular risk factors were examined in 3562 elderly (aged 71 to 93 years) Japanese American men from the Honolulu Heart Program who were reexamined between 1991 and 1993. Insulin distributions were skewed (mean and median: 16.8 and 12 microU/mL for fasting; 117.2 and 93 microU/mL for 2-hour); fasting but not 2-hour insulin levels declined significantly with age (P < .0001 and P = .54, respectively). Factors most strongly correlated with insulin included measures of obesity, fat distribution, and levels of triglyceride, glucose (r = .38 to r = .50 fasting, r = .21 to r = .27 2-hour), and HDL cholesterol (r = -.41 and r = -.22, respectively). Other correlates included fibrinogen, hematocrit, heart rate, blood pressure, cigarettes per day (all positive), alcohol, physical activity, and forced vital capacity (negative). Associations were also evident across risk factor quintiles. Insulin levels were significantly elevated in men with hypertension and diabetes. In multiple linear regression analyses, log10 fasting insulin was positively and independently associated with body mass index, triglycerides, glucose, fibrinogen, hematocrit, heart rate, diabetes, and hypertension and negatively associated with HDL cholesterol, physical activity, and forced vital capacity. In general, results were similar for log10 2-hour insulin and when subjects who fasted < 12 hours or had diabetes were excluded. Substitution of medication use and blood pressure for hypertension indicated independent associations of medication use but not blood pressure with insulin.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1995

Cigarette smoking sensitizes and desensitizes impedance-measured ADP-induced platelet aggregation in whole blood.

The effect of smoking on platelet aggregation appears to produce conflicting results, with some studies indicating an enhancement and others a decrease of aggregation. This epidemiological study of 120 male smokers, a subset of the Caerphilly Heart Disease Study, examined the relationship of two dimensions of smoking (time proximity of last cigarette before venepuncture and serum nicotine concentration) with threshold dose of adenosine diphosphate (ADP) necessary to induce platelet aggregation in whole blood. Means (range) of ADP threshold dose and nicotine concentration were 1.66 (0.5-2.5, censored) microM and 12.2 (0-35.2) ng/ml. Men smoking within 30 min of venepuncture demonstrated lower ADP threshold doses (-0.48 microM lower [95% C.I.: -0.95, -0.02])--reflecting increased sensitivity. Men with higher nicotine concentration had higher ADP threshold doses (Regression Coefficient: +0.032 microM per ng/ml [95% C.I.: 0.003, 0.062])--reflecting decreased sensitivity. Men smoking 30 min or more before venepuncture who also had high nicotine concentration (25-30 ng/ml) demonstrated the highest ADP threshold doses compared to never smokers and to men smoking the previous day (approximately 2.20 vs 1.86 and 1.81 microM). Relations involving nicotine concentration do not necessarily reflect a pharmacological effect although the potential for a short term nicotine mediated tolerance effect cannot be dismissed. These observations support an hypothesis suggesting a temporal sequence of platelet sensitization and desensitization during smoking.

Adenosine Diphosphate↗
PubMed1995

Associations among baseline physical activity and subsequent cardiovascular risk factors.

To determine stability of cross-sectional associations between physical activity and cardiovascular risk factors and provide information regarding possible independent effects of physical activity on reduced cardiovascular disease, this report examined associations among baseline physical activity and risk factors measured over 15 yr. Subjects were 1,379 Honolulu Heart Program participants who were evaluated at baseline and three subsequent examinations. For men initially 45-54 yr, higher physical activity level was significantly associated cross-sectionally and at 2 yr with lower diastolic blood pressure, body mass index, and skinfold thicknesses, and at 5 yr with higher high density lipoprotein (HDL) cholesterol. By the 15-yr examination, only associations between physical activity level and skinfold thicknesses remained significant. For men 55-68 yr, significant cross-sectional and 2-yr associations were found between higher physical activity level and lower skinfold thicknesses, and higher HDL cholesterol at 5 yr. Higher physical activity continued to be associated with lower skinfold thicknesses and was related to lower systolic blood pressure by the 15-yr examination. Results suggest that most cross-sectional associations between physical activity and risk factors diminish over time, providing support for prospective investigations that find physical activity has a beneficial effect on reduced cardiovascular disease partially independent of traditional risk factors.

Activities of Daily Living↗
PubMed1994

Body mass index and thromboembolic stroke in nonsmoking men in older middle age. The Honolulu Heart Program.

BACKGROUND AND PURPOSE: While evidence suggests that obesity has an independent relation to coronary artery disease, similar findings for stroke have not been established. The purpose of this study was to examine the relation between body mass index and the risk of thromboembolic stroke independently of other risk factors. METHODS: Since 1965, the Honolulu Heart Program has followed a cohort of men in a prospective study of cardiovascular disease. This article examines the relationship between the baseline measurement of body mass index and the risk of thromboembolic stroke in 1163 nonsmoking men in older middle age (55 to 68 years). Men who had an elevated risk of stroke due to hypertension, diabetes, and other risk factors were excluded from the analysis. RESULTS: After 22 years of follow-up, the rate of stroke increased significantly with increasing levels of body mass (P < .01). In the bottom tertile of the body mass index, the rate of thromboembolic stroke was 28.7 per 1000 (11/383). In the middle tertile, the rate was increased by 40% to 40.7 per 1000 (16/393), and in the top tertile, the rate of thromboembolic stroke was 55.4 per 1000 (21/387), a twofold excess compared with the bottom tertile. After adjustment for age and the residual effects of confounding risk factors, including systolic blood pressure and serum glucose, the estimated relative risk of stroke for the average body mass index in the top tertile (26.6 kg/m2) compared with that in the bottom tertile (20.3 kg/m2) was 2.1 (95% confidence interval, 1.1 to 4.1). These findings were not affected by coronary events that occurred in the course of follow-up, nor did they appear to be influenced by deaths from other causes. CONCLUSIONS: We conclude that elevated body mass is associated with an increased risk of thromboembolic stroke in nonsmoking men in older middle age who are free of commonly observed conditions related to cardiovascular disease.

Age Factors↗
PubMed1994

Fish consumption may limit the damage of smoking on the lung.

High fish consumption is characteristic of Japanese-American men of the Honolulu Heart Program (HHP). Analyses of data from the Atherosclerosis Risk in Communities (ARIC) study suggest high fish intake protects the lung against smoking damage. Measurements of forced expiratory volume in 1 s (FEV1) and smoking status in the HHP cohort were done at the first examination in 1965-68. Among 8,006 men, 45 to 68 yr, 6,346 had acceptable spirograms. Within current smokers, 1,545 men consumed fish less than twice a week, and 1,264 ate fish twice a week or more. Controlling for cigarettes/d, age, height, and daily calories, separate regression models indicated an average decrease of -10.1 ml for each additional yr of smoking (95% Confidence Interval [CI]: -13.6, -6.5) at low levels of fish intake, and a decrease of -4.4 ml (95% CI: -8.2, -0.6) at high levels. The coefficients were significantly different (p = 0.03). These differences reflect a predicted FEV1 144 ml (95% CI: 62, 227) higher in the high fish group at > or = 40 yr of smoking, but no difference at < or = 35 yr. Similar analyses were conducted for cigarettes/d. On average, the FEV1 decline for each additional cigarette/d was not significantly different among subjects with low versus high fish intake. However, the predicted FEV1 at < or = 30 cigarettes/d was 52 ml (95% CI: 17, 87) higher in the high fish consumption group. No significant difference in FEV1 was noted between groups at > 30 cigarettes/d. These findings suggest that the protective role of fish is "saturated" at higher "doses" of cigarette smoking.

Aged↗
PubMed1993

Road traffic noise, noise sensitivity and psychological disorder.

The relationship between traffic noise exposure and psychological morbidity was assessed using the population-based Caerphilly Collaborative Survey of 2398 men from Caerphilly, South Wales. The findings showed that traffic noise exposure levels were strongly associated with annoyance to noise. Noise-sensitive men were more likely to be highly annoyed by noise exposure than less noise-sensitive men. There was no direct association between noise exposure level and psychological morbidity but there were provocative interactions with noise sensitivity. The role of noise sensitivity is discussed as an indicator of vulnerability to environmental stressors and a measure of negative affectivity and over-reporting.

Cohort Studies↗
PubMed1992

A population survey of ischaemic heart disease and minor psychiatric disorder in men.

Associations between ischaemic heart disease and psychiatric morbidity in hospital recruited samples may be confounded by differential referral of patients with co-morbidity. Associations of angina, past history of myocardial infarction, blood pressure, and electrocardiographic evidence of ischaemia with psychiatric disorder can best be examined in community samples as reported here in 2204 middle-aged men from the Caerphilly Collaborative Study. There was a strong association between past history of myocardial infarction, non-specific chest pain, Angina Grade II and psychiatric disorder measured by the 30-item General Health Questionnaire. Electrocardiographic evidence of ischaemia alone was not significantly associated with psychiatric disorder. It is suggested that non-specific chest pain is a symptom of psychiatric disorder; conversely in severe angina psychiatric disorder is secondary to the pain, restricted activity and threat to life which angina implies.

Chest Pain↗
PubMed1992

Alcohol and platelet aggregation: the Caerphilly Prospective Heart Disease Study.

Intakes of alcohol and saturated fatty acids were determined through a dietary questionnaire from 1600 men (aged 49-66 y) in the Caerphilly Prospective Heart Disease Study. Platelet aggregation induced by thrombin adenosine disphosphate (ADP), and collagen was studied in subjects who had fasted and had not recently taken drugs affecting platelets. In subjects who drank alcohol, the odds ratio of a high response to aggregation was significantly reduced (primary ADP, P less than 0.05; secondary ADP, P less than 0.001; collagen, P less than 0.02). The significance was enhanced by adjusting for smoking and by including only the subjects with a high intake of saturated fatty acids or a low intake of polyunsaturated fatty acids. By contrast, the responsiveness to thrombin was slightly increased at all levels of alcohol consumption. We therefore suggest that part of the effects of alcohol on coronary heart disease may be mediated by a dose-dependent effect on certain platelet functions, modulated by the intake of dietary fat.

Adenosine Diphosphate↗
PubMed1991

Blood lead and platelet aggregation--evidence for a causal association.

Adenosine diphosphate (ADP) and thrombin are agonists of platelet aggregation in which intracellular calcium plays a significant role as a signal transducer. Lead is a well established toxicological agent affecting intracellular mechanisms controlling free ionized calcium concentration in a number of cell lines. This epidemiological study is the first demonstration of a significant relationship between the extent of primary ADP-induced platelet aggregation measured by optical densitometry in platelet rich plasma (PRP) and blood lead concentration. High blood lead levels are associated with decreased aggregation in this population of 2,150 men aged 49-65 years. This is reflected by a negative regression relationship of -0.19% of maximal extent (PRP vs platelet poor plasma) of aggregation per microgram of Pb/dl (T = -3.82, p less than 0.001). In contrast, no relationship is noted between thrombin-induced aggregation and blood lead concentration. Smoking behaviour represents a potential confounder which may be the explanation for the observed relationship. However, because smoking status is simultaneously related to both ADP- and thrombin-induced aggregation, but is simultaneously related to ADP-induced aggregation and blood lead concentration in a different way, the observed relation is likely to be causal. The mechanisms by which ADP and thrombin effect intracellular calcium transduction signals appear to be distinctively different. The findings in this population-based study are not inconsistent with this difference.

Adenosine Diphosphate↗
PubMed1991

Social factors and minor psychiatric disorder in middle-aged men: a validation study and a population survey.

A cross-sectional survey of minor psychiatric disorder is reported in a representative community sample of 2204 men between the ages of 45 years and 64 years living in Caerphilly, South Wales. Minor psychiatric disorder was measured by the 30-item General Health Questionnaire and validated by the Clinical Interview Schedule in a consecutive sample of 97 men, weighted to provide one-third cases, two-thirds non-cases. A case threshold of 4/5 on the General Health Questionnaire was chosen on the basis of 'ROC' analysis. An overall estimated 'true' prevalence rate for minor psychiatric disorder of 22.0% was found, with 22.3% of men scoring 5 or more on the General Health Questionnaire. Rates of minor psychiatric disorder were higher in widowed and divorced men than in married men but were also, unexpectedly, lower in single as opposed to married men. There was no social-class gradient in minor psychiatric morbidity but a lower rate in Social Class III NM may be largely explained by lower unemployment rates. There were markedly higher rates of minor psychiatric morbidity in unemployed men and those who retired ill. Men with no available social contacts had higher rates of morbidity than men with some or high social contacts.

Cross-Sectional Studies↗
PubMed1991

Design and methods for a survey of lead usage and exposure monitoring in California industry.

A probability sample of California workplaces in 1986 estimated the numbers of workers using lead and their coverage by biological and environmental monitoring. Study steps included (1) identifying 505 stand ard industrial classifications (SICs) with possible lead use; (2) creating an employer lis; (3) identifying for oversampling seven single SICs and a group of 165 SICs with documented high ambient air lead; (4) further stratification by workforce size; (5) prediction from National Institute for Occupational Safety and Health surveys the number of lead-using workers for each employer; (6) drawing facilities into the sample with selection probability proportional to the number of workers predicted to use lead; (7) adjusting the sample selection if an employer listing covered multiple facilities; (8) sending a first-stage telephone/mail questionnaire to identify lead users, who were sent a second questionnaire; (10)follow-up which, aided by statutory authority, resulted in completion rates over 90%; (11) ranking lead-using processes by intensity of exposure; and (12) analysis. Sources of error include random sampling error, misleadingly large standard errors because sampling was with replacement, gaps in the employer list, and inaccurate responses. As a measure for the probability proportional to size sampling, total work force count would have been superior to the predicted number of lead users. Restriction to a single hazard makes a questionnaire-based study feasible, but names of workers, rather than counts, should be requested and a subsample should be visited.

California↗
PubMed1991

Lead use in California industry: its prevalence and health implications.

An estimated 230,000 workers were reported to work in lead-using activities as a result of a 1986 statistical survey of employers in California. However, 68% of these workers worked in activities of relatively low hazard. This included 114,000 workers engaged in electronic soldering. Over 1800 workers were reported to work in battery manufacture, a relatively high-hazard activity, but with consistent monitoring and protection. In contrast, over 4300 workers were involved in radiator repair activities, a high-hazard activity with inconsistent monitoring and protection. Over 8% of construction workers were reported to work in lead-using processes. This sector is exempt from federal Occupational Safety and Health Administration (Fed/OSHA) and California Occupational Safety and Health (Cal/OSHA) lead standards, yet some of the most hazardous activities (welding, grinding, and cutting, etc.) occurred here. Comparison of projections from the National Occupational Hazard Survey of potential lead exposure in California with these survey results suggests consistent and reliable assessment of the major sources of potential occupational exposure to lead.

California↗
PubMed1991

Long-term diet modification and platelet activity.

Platelet activity was assessed in a sub-sample of 56 participants in the MRC Diet and Reinfarction Trial (DART). Men whose diets contained a high ratio of polyunsaturated to saturated fatty acids (a P:S ratio of greater than 0.5) showed reduced secondary platelet aggregation to adenosine diphosphate (ADP) in platelet-rich plasma (PRP), and diminished platelet aggregation to ADP in whole blood. A trend of reduced secondary platelet aggregation to ADP with increasing dietary eicosapentaenoic acid was noted, but this was not statistically significant. The results of this study and the MRC Diet and Reinfarction Trial suggest a mediatory role for platelet activity in the relationship between diet and ischaemic heart disease.

Adult↗
PubMed1991

Ischemic heart disease and platelet aggregation. The Caerphilly Collaborative Heart Disease Study.

The Caerphilly Collaborative Heart Disease Study is based on a large cohort of men (2,398) aged 49-66 years at the time of study. Platelet aggregation induced by collagen, thrombin, and ADP was measured in fasting blood samples and was related to prevalent angina, past myocardial infarction, and electrocardiographic evidence of ischemic heart disease. A number of subjects had taken aspirin, other nonsteroidal anti-inflammatory drugs, or other drugs affecting platelet aggregation 7 days before blood sample collection; after the exclusion of these subjects, data were available for 1,811 men. No relations were demonstrated with angina, but significant relations were shown between past myocardial infarctions and electrocardiographic evidence of ischemia and ADP-induced aggregation (both primary and secondary) and between electrocardiographic evidence of ischemia and thrombin-induced aggregation. The strongest relation indicated more than a twofold increase in the odds of a past myocardial infarction in subjects of the highest fifth of ADP-induced primary platelet aggregation compared with the lowest fifth. No significant relations were detected with collagen-induced aggregation. Accounting for a number of possible confounding factors had a relatively small impact on the relations between platelet aggregation and ischemic heart disease. Other evidence, including the well-established effect of aspirin on reducing the incidence of ischemic heart disease, indicates that the relations we describe are unlikely to be simply an effect of IHD on platelets.

Aged↗