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Biomedical subjects

J W Yarnell

Publications and source records attributed to J W Yarnell.

At least 19 recordsLinked to original sources
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

Height: a risk marker for ischaemic heart disease: prospective results from the Caerphilly and Speedwell Heart Disease Studies.

The predictive power of height for future ischaemic heart disease (IHD) was examined in 4860 men from two communities in South Wales and the West of England. At follow-up, men in the shortest fifth of the height distribution had experienced twice as many incident IHD events (fatal and non-fatal myocardial infarction) as was the case for men from the tallest fifth. Adjustment for age, social class and smoking habit failed to alter these relationships significantly. In the data from South Wales, determinants of height were examined; birth rank and number of siblings showed a trend with height. This trend was found only in men whose fathers were manual workers and may be related to inadequate nutrition in the higher birth ranks and larger families. These results support the suggestion that early childhood factors may be relevant to IHD in middle age and possible mechanisms are discussed.

Birth Order↗
PubMed1992

Plasma triglyceride and high density lipoprotein cholesterol as predictors of ischaemic heart disease in British men. The Caerphilly and Speedwell Collaborative Heart Disease Studies.

OBJECTIVE: To assess the roles of plasma triglyceride and high density lipoprotein (HDL) cholesterol concentrations in predicting ischaemic heart disease. DESIGN: Two prospective cohort studies with common core protocols. SETTING AND PARTICIPANTS: Both cohorts are 100% samples of middle aged men. In Caerphilly the 2512 men were living within a defined area. In Speedwell the 2348 men were registered with local general practitioners. MAIN OUTCOME MEASURES: Fasting blood samples were taken at initial examination and plasma lipid concentrations were measured. Major ischaemic heart disease events were assessed from hospital notes, death certificates, and electrocardiograms. RESULTS: At first follow up, after an average of 5.1 years in Caerphilly and 3.2 years in Speedwell, 251 major ischaemic heart disease events had occurred. Men with triglyceride concentrations in the top 20% of the distribution had a relative odds value for ischaemic heart disease of 2.3 (95% confidence interval (95% CI) 1.3 to 4.1) compared with men in the bottom 20%, after adjusting for both plasma total and HDL cholesterol, and non-lipid risk factors. Men in the lowest 20% of the distribution of HDL cholesterol concentration had a relative odds value of 1.7 (95% CI 1.0 to 2.8) compared with the top 20%, after adjustment was made for total cholesterol and triglyceride concentrations, and non-lipid risk factors. These relations were not caused by beta blockers, which were being taken by 5% of the men. CONCLUSIONS: Plasma triglyceride concentration predicts major ischaemic events after allowance is made for total and HDL cholesterol concentrations and other risk factors. In these populations, triglyceride is a more important predictor than total cholesterol concentration.

Adrenergic beta-Antagonists↗
PubMed1991

Association between infection with Helicobacter pylori and risk of gastric cancer: evidence from a prospective investigation.

OBJECTIVE: To investigate the association between gastric cancer and prior infection with Helicobacter pylori. DESIGN: Case-control comparison of prevalence of IgG antibodies to H pylori in blood samples collected prospectively, before diagnosis of gastric cancer in the cases. Presence of H pylori antibody (greater than 10 micrograms IgG/ml) determined by enzyme linked immunosorbent assay (ELISA). SUBJECTS: 29 men with a subsequent diagnosis of gastric cancer and 116 aged matched controls selected from over 22,000 middle aged men participating in two ongoing cohort studies (the British United Provident Association study and the Caerphilly collaborative heart disease study), who had provided blood samples during 1975-1982. RESULTS: 20 of the 29 cases (69%) and 54 of the 116 controls (47%) were positive for H pylori specific antibody. The median specific IgG concentration was significantly higher in the cases than controls (90 micrograms/ml v 3.6 micrograms/ml, p less than 0.01). The estimated odds ratio for the risk of gastric cancer in those with a history of infection with H pylori was 2.77 (95% confidence interval 1.04 to 7.97, 2p = 0.039). CONCLUSIONS: H pylori infection may be an important cause of gastric cancer; between 35% and 55% of all cases may be associated with such an infection.

Adult↗
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

Helicobacter pylori infection rates in relation to age and social class in a population of Welsh men.

The seroprevalence of IgG antibodies to Helicobacter pylori was determined using a standard enzyme linked immunosorbent assay in a population of 749 randomly selected men, aged 30-75 years, from Caerphilly, South Wales. The overall prevalence of H pylori was 56.9%, increasing sharply in middle age from 29.8% in those aged 30-34 to over 59% in those aged 45 or older (p less than 0.0001). Age standardised seroprevalence rates were lowest in combined social class categories I and II (49.2%), intermediate in categories IIIN and M (57.5%), and highest in categories IV and V (62.2%) (p = 0.01). In those aged 30-34 years, the prevalence rate for those in combined social class categories IV and V was 57.9% - double the rate for social class categories IIIM and N (28.3%) and five times the prevalence rate in those in social class categories I and II (11.1%). These differences in the infection patterns of H pylori by social class are consistent with patterns of peptic ulcer disease and gastric cancer.

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↗
PubMed1991

Fibrinogen, viscosity, and white blood cell count are major risk factors for ischemic heart disease. The Caerphilly and Speedwell collaborative heart disease studies.

BACKGROUND: Recent studies have suggested that hemostatic factors and white blood cell count are predictive of ischemic heart disease (IHD). The relations of fibrinogen, viscosity, and white blood cell count to the incidence of IHD in the Caerphilly and Speedwell prospective studies are described. METHODS AND RESULTS: The two studies have a common core protocol and are based on a combined cohort of 4,860 middle-aged men from the general population. The first follow-up was at a nearly constant interval of 5.1 years in Caerphilly and 3.2 years in Speedwell; 251 major IHD events had occurred. Age-adjusted relative odds of IHD for men in the top 20% of the distribution compared with the bottom 20% were 4.1 (95% confidence interval, 2.6-6.5) for fibrinogen, 4.5 (95% confidence interval, 2.8-7.4) for viscosity, and 3.2 (95% confidence interval, 2.0-4.9) for white blood cell count. Associations with IHD were similar in men who had never smoked, exsmokers, and current smokers, and the results suggest that at least part of the effect of smoking on IHD is mediated through fibrinogen, viscosity, and white blood cell count. Multivariate analysis shows that white blood cell count is an independent risk factor for IHD as is either fibrinogen or viscosity, or possibly both. Jointly, these three variables significantly improve the fit of a logistic regression model containing all the main conventional risk factors. Further, a model including age, smoking habits, fibrinogen, viscosity, and white blood cell count predicts IHD as well as one in which the three hemostatic/rheological variables are replaced by total cholesterol, diastolic pressure, and body mass index. CONCLUSION: Jointly, fibrinogen, viscosity, and white blood cell count are important risk factors for IHD.

Blood Viscosity↗
PubMed1990

The association of platelet and red cell count with platelet impedance changes in whole blood and light-scattering changes in platelet rich plasma: evidence from the Caerphilly Collaborative Heart Disease Study.

This epidemiological study was undertaken to explore possible relationships among various haematological indices, prevalent ischaemic heart disease and platelet "function" as measured by two rather different methods. ADP-induced platelet impedance changes in whole blood were strongly associated with prevalent ischaemic heart disease in a general population of 49-66 year men at increased risk. Adenosine diphosphate (ADP) induced platelet aggregation in platelet rich plasma (PRP) at a constant platelet count and also the whole blood platelet count and red cell (RBC) count were strongly and independently related to ADP-induced platelet impedance changes. Both platelet count and platelet aggregation in PRP assessed by changes in optical density were directly related to increasing platelet "sensitivity" as measured by impedance changes in whole blood but RBC count was inversely related. Positive independent relationships between platelet impedance changes and plasma viscosity and fibrinogen were markedly attenuated when platelet count was taken into account, but this finding does not discount a role for these factors in platelet aggregation. No relationship was noted between white blood cell (WBC) count and platelet impedance changes; however, a significant inverse relationship was noted with platelet aggregation in PRP. These findings indicate that laboratory-based experimental findings can be observed in population based studies, and that these haematological factors may be important indicators of ischaemic disease in the population.

Adenosine Diphosphate↗
PubMed1990

The diets of men in four areas of the UK: the Caerphilly, Northern Ireland, Edinburgh and Speedwell studies.

Nutrient intakes in four areas of the UK were compared, 7-d weighed intake data were obtained for representative community samples of middle-aged men in Caerphilly (South Wales), Northern Ireland, Edinburgh and Bristol (Speedwell). Intakes of energy were higher in Edinburgh than in the other three areas, but following allowance for this, differences in nutrient intakes were very small. The exceptions were P/S ratio and alcohol consumption. The P/S ratio for Northern Ireland (0.38) was considerably higher than that for the other areas (0.30 to 0.32). The proportion of heavy drinkers was higher in Edinburgh (15 per cent) than in other areas (5-9 per cent) and the proportion of abstainers was highest in Northern Ireland (38 per cent). Differences in nutrient intakes did not parallel the differences in ischaemic heart disease (IHD) mortality rates between the areas.

Alcohol Drinking↗
PubMed1990

Body fatness and frame size: the Caerphilly study.

The effect of adjusting height-weight indices for frame size on the prediction of body fatness was investigated in a community sample of 2512 men aged 45-59 years. Body fatness was assessed from skinfold thickness measurements at four sites: triceps, biceps, subscapular and supra-iliac. Body diameters (biacromial, bi-iliocristal, wrist or knee) were used as estimates of frame size. Body diameters were not independent of body fatness, wrist diameter showing the lowest association with skinfold thickness measurements. Adjustment of weight/height2 (W/H2) for frame size had little effect on the prediction of body fatness, the correlation coefficient for body fatness with W/H2 (r = 0.76) being almost identical to that for W/H2 adjusted for wrist diameter (r = 0.74).

Adipose Tissue↗
PubMed1989

Blood viscosity and hearing levels in the Caerphilly Collaborative Heart Disease Study.

Data from 342 men who are participants in the Caerphilly Collaborative Heart Disease Study were used to replicate a previous report of a significant relationship between measures of whole-blood viscosity and hearing levels in persons with sensorineural hearing impairment. In the unselected data, there were significant relationships between measures of whole-blood viscosity at high shear rates and hearing threshold levels at 2000 and 4000 Hz, even after accounting for the effects of age and socioeconomic group. In a subset of the data containing 124 persons selected on the basis of likely sensorineural hearing impairment, there were significant relationships between whole-blood viscosity and hearing level at all frequencies, with stronger effects at the higher frequencies. The data support the contention of a potentially important relationship between whole-blood viscosity and sensorineural hearing impairment.

Audiometry, Pure-Tone↗