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Biomedical subjects

H A Neil

Publications and source records attributed to H A Neil.

At least 55 records · Page 3Linked to original sources
PubMed1992

Relation between insulinemia, body mass index, and lipoprotein composition in healthy, nondiabetic men and women.

Altered lipoprotein composition may be a better predictor of cardiovascular disease than modestly increased serum lipid concentrations, although possible interactions between lipoprotein composition, obesity, and insulinemia have not been fully elucidated. Therefore, we investigated the association between different measures of insulinemia and lipoproteins in 297 healthy Caucasian men (body mass index [BMI] less than 27 in 233, greater than 27 [obese] in 64) and 295 healthy Caucasian women (BMI less than 25 in 198, greater than 25 [obese] in 97). Associations observed in both obese and nonobese men and women were between increasing tertiles of most insulin measures and serum triglyceride concentrations (p = 0.079-0.004) and the ratio of low density lipoprotein to high density lipoprotein cholesterol (p = 0.094-0.008). Graded reductions in the high density lipoprotein cholesterol to apolipoprotein A-I ratio were also recorded in obese women, with increasing tertiles of fasting (p = 0.014-0.007) and postglucose load (p = 0.001) serum insulin levels, after correcting for BMI and triglyceride concentrations. Less marked graded increases in the triglyceride to apolipoprotein B ratios were recorded in obese women with increasing tertiles of fasting (p = 0.001-0.006) and postglucose challenge (p = 0.081) insulinemic measures. In men with normal or slightly elevated cholesterol levels (fasting serum cholesterol less than 6.5 mmol/l), hyperapobetalipoproteinemia was recorded with increasing tertiles of insulinemia (p = 0.006, correcting for BMI and triglyceride concentrations), as well as in subjects with hypertriglyceridemia (fasting serum triglycerides greater than 1.70 mmol/l) (p = 0.004, correcting for BMI and age). Hyperinsulinemia and insulin resistance are associated with altered lipoprotein composition in obese women, presumably reflecting a complex interplay between sex hormones, body mass, and insulin action. Insulin resistance appears to be more associated with apolipoprotein B concentrations in men. The hyperinsulinemic nondiabetic subject may be at increased risk of cardiovascular disease because of altered concentrations of apolipoprotein concentrations and lipoprotein composition.

Adult↗
PubMed1992

The management of hyperlipidaemia: are specialist lipid clinics needed?

A survey of all general practitioners in Oxfordshire was undertaken to determine what use they wanted to make of a district lipid clinic, and to assess how effectively it met their needs. The response rate was 85% (288/340) but some respondents failed to answer each section of every question. One hundred and eighty-five general practitioners (64%) had previously referred patients to the clinic. Most respondents selectively asked for blood cholesterol measurements in patients with major cardiovascular risk factors (94%, 266/283), and few routinely asked for cholesterol as part of a health check (17%, 43/258). Most thought that referral to a clinic was appropriate for children (65%, 149/229), for patients aged 20 to 39 (85%, 209/247), and for older patients aged up to 60 (77%, 186/243). Ninety-four per cent (260/277) wanted access to specialist advice for patients with a cholesterol concentration exceeding 8.0 mmol l-1, and 73% (197/270) wanted specialist advice before starting treatment with a lipid-lowering drug. Although most respondents rated the service provided by the clinic favourably, more than half would have liked more information on prognosis, drug treatment, long-term follow-up, and screening of family members. We conclude that general practitioners would like access to specialist advice for the management of severe hyperlipidaemias, and that cardiovascular screening programmes in primary care have important resource implications for specialist services.

Adult↗
PubMed1991

Cholesterol screening and life assurance.

OBJECTIVES: To examine how insurance companies assess proposals for life assurance from applicants with raised cholesterol concentrations and to determine the excess mortality rating applied. DESIGN: Survey of 49 companies underwriting term life assurance. SETTING: United Kingdom. SUBJECTS: Four fictional men aged 30 seeking 20 year term policies paying benefit only on death. Two had total cholesterol concentrations of 6.4 and 8.1 mmol/l but no other cardiovascular risk factors; one was overweight, hypertensive, smoked 20 cigarettes daily, and had a total cholesterol concentration of 8.1 mmol/l; and one had possible familial hypercholesterolaemia and a total cholesterol concentration of 10.7 mmol/l after treatment. MAIN OUTCOME MEASURE: Percentage excess mortality rating. RESULTS: All companies used explicit criteria to assess the mortality risk associated with hyperlipidaemias, and 47 companies applied the same criteria to men and women. No excess mortality rating was imposed on an applicant with a total cholesterol concentration of 6.4 mmol/l, but a small excess was applied to an applicant with a concentration of 8.1 mmol/l (median excess 50%, range 0-75%). When multiple cardiovascular risk factors were present the same concentration of 8.1 mmol/l resulted in a substantial excess (median 135%, range 50-200%). A smaller but more variable excess was applied to an applicant with possible familial hypercholesterolaemia (median 75%, range 0-200%). CONCLUSIONS: Despite considerable differences among companies in the excess mortality ratings applied, increases in term life assurance premiums are likely to be restricted to patients with severe hypercholesterolaemia, in particular those with familial hypercholesterolaemia. In the absence of other cardiovascular risk factors milder hypercholesterolaemia is unlikely to result in higher premiums.

Adult↗
PubMed1991

A population-based study of the incidence of complications associated with type 2 diabetes in the elderly.

One hundred and eighty-eight known Type 2 diabetic patients aged over 60 years identified by a geographically based survey of a population of 40,076 were followed for a median of 6 years to determine the incidence of various complications. There were 63 deaths and two patients were lost to follow-up. The presence of complications was determined using a structured questionnaire and clinical examination. Incidence rates of ischaemic heart disease, stroke, and peripheral vascular disease (PVD) were 56 (95% CI 41-75), 22 (13-35), and 146 (117-174) 1000-person-years-1 of follow-up, respectively. Rates of stroke and PVD rose significantly with age. Retinopathy occurred at a rate of 60 (42-83) 1000-person-years-1 and cataract at 29 (17-46) 1000-person-years-1 although visual acuity in survivors did not deteriorate overall, probably reflecting the high mortality associated with cataract. The rate of proteinuria (albumin concentration greater than 300 mg l-1) was 19 (9-34) 1000-person-years-1. Incidence rates were unrelated to sex or duration of diabetes. Diabetes is associated with a continuing incidence of complications into old age. Adequate facilities are required to assess and treat the resulting morbidity in a population with an increasing proportion of elderly people.

Age Factors↗
PubMed1990

Lipid screening: is it enough to measure total cholesterol concentration?

OBJECTIVES: To determine whether measurement of total cholesterol concentration is sufficient to identify most patients at lipoprotein mediated risk of coronary heart disease without measurement of triglyceride and high density lipoprotein (HDL) cholesterol concentrations. DESIGN: Cross sectional screening programme. SETTING: Six general practices in Oxfordshire. PATIENTS: 1901 Men and 2068 women aged 25-59. MAIN OUTCOME MEASURE: Cardiovascular risk as assessed by fasting venous plasma concentrations of total cholesterol, triglyceride, and HDL cholesterol. RESULTS: 2931 Patients (74% of those screened) had a total cholesterol concentration of less than 6.5 mmol/l. If the triglyceride concentration had not been measured in these patients isolated hypertriglyceridaemia (greater than or equal to 2.3 mmol/l) would have remained undetected in 185. Among these 185 patients, however, 123 were overweight or obese and only 18 (0.6% of those screened) had an increased risk associated with both a raised triglyceride concentration (greater than or equal to 2.3 mmol/l) and a low HDL cholesterol concentration (less than 0.9 mmol/l). Conversely, in the 790 patients with predominant hypercholesterolaemia (cholesterol concentration greater than or equal to 6.5 mmol/l and triglyceride concentration less than 2.3 mmol/l) measurement of HDL cholesterol concentration showed that 348 (9% of those screened) had only a moderately increased risk with a ratio of total to HDL cholesterol of less than 4.5 and 104 had a low risk with a ratio of less than 3.5. CONCLUSIONS: Fasting triglyceride and HDL cholesterol concentrations identify few patients at increased risk of coronary heart disease if the total cholesterol concentration is less than 6.5 mmol/l. HDL cholesterol and triglyceride concentrations should, however, be measured in patients with a total cholesterol concentration exceeding this value. Total cholesterol concentration alone may overestimate risk in a considerable number of these patients, and measurement of HDL cholesterol concentration allows a more precise estimate of risk. Measurement of the triglyceride concentration is required to characterise the lipoprotein abnormality. A patient should not be started on a drug that lowers lipid concentrations without having had a full lipoprotein assessment including measurement of HDL cholesterol concentration.

Adult↗
PubMed1990

Lens opacity and mortality in diabetes.

A population-based cohort of 294 diabetic patients were examined for the presence of lens opacities and followed up for a median of 6 years. Only two patients were lost to follow-up but there were 73 deaths, 49 in the 108 patients with opacities and 24 in the 184 patients without (odds ratio 2.4, 95% Cl 1.5-3.9). Lens opacities were a powerful predictor of death and the effect was independent of other prognostic factors. The presence of cataract identifies a high risk sub-group of elderly diabetic patients.

Age Factors↗
PubMed1990

Biometry of the crystalline lens in early-onset diabetes.

Lenticular biometry on non-cataractous lenses has been studied by means of Scheimpflug photography and digital image analysis in 153 patients with early-onset insulin-dependent diabetes and 153 non-diabetic controls. Anteroposterior axial lens thickness, cortical thickness, nuclear thickness, anterior and posterior lenticular curvatures, and anterior chamber depth were assessed. Highly significant differences between the lenses of the diabetic subjects and non-diabetic controls were found. After the effect of age had been accounted for within the diabetic subgroup, diabetic duration was found to be a highly significant determinant of lens dimensions, such that age-related dimensional changes for various biometric parameters were accelerated by between 52% and 121% after the onset of diabetes. Because the diabetic duration of the early-onset diabetic subjects studied in this work was accurately known, this report is the first in which a precise assessment of the effect of 'true' diabetic duration on lens biometry has been possible.

Adolescent↗
PubMed1989

Within-clinic reagent strip lipid measurement.

The agreement between the Reflotron dry chemistry analyser and laboratory methods for measurement of total cholesterol and triglycerides was assessed by studying the between-method variability for individual samples. A paired comparison of replicate measurements from venous blood was made for 105 cholesterol and 90 triglyceride specimens. There was no significant mean difference between the two methods for cholesterol measurement (difference 0.02 mmol l-1, 95% Cl -0.07 to 0.10 mmol l-1) but there were wide limits of agreement (+/- 2SD) of -0.87 to 0.90 mmol l-1. Some of the differences in measurement were large enough to be clinically misleading and would result in inconsistencies in diagnostic assignment between the two methods. Both methods achieved relatively poor repeatability which limited the agreement possible (coefficient of repeatability, defined as 2SD of the differences, 0.59 mmol l-1 for the Reflotron and 0.38 mmol l-1 for the laboratory). The repeatability of triglyceride measurement was similar for the Reflotron and laboratory (coefficient of repeatability 0.24 mmol l-1 and 0.27 mmol l-1, respectively). However, there was a significant systematic difference between methods, with the Reflotron reading 0.30 mmol l-1 less than the laboratory method (95% Cl 0.26 to 0.35 mmol l-1) and the limits of agreement between the methods were -0.09 to 0.70 mmol l-1. It is important that clinicians recognize the limits of agreement between dry chemistry analysers and laboratory methods and take these into account when using them to screen for hyperlipidaemia or to monitor treatment of hyperlipidaemic diabetic patients.

Cholesterol↗
PubMed1988

Diabetes mellitus: attitudes, knowledge and glycaemic control in a cross-sectional population.

A questionnaire to households in Oxfordshire identified 431 diabetic patients living in the area and 272 of them completed a questionnaire about their attitudes to and knowledge of diabetes, and were subsequently interviewed. Most did not regard diabetes as a serious disease and had little knowledge of possible complications. Patients found dietary compliance the most difficult part of their treatment. Among non-insulin treated patients there was a significant association between difficulty with diet and body mass index and glycosylated haemoglobin values. The results suggest that there is a need for more effective advice on diet and for better education of patients about the nature of diabetes and its complications.

Adult↗
PubMed1987

Mortality among male anaesthetists in the United Kingdom, 1957-83.

A cohort of 3769 male anaesthetists resident in the United Kingdom between 1957 and 1983 was followed up for a total of 51,431 person years of observation. All subjects were fellows of the Faculty of Anaesthetists and held full registration with the General Medical Council. With all men in social class I being taken as the standard, the standardised mortality ratio among anaesthetists for all causes of death was 68 (95% confidence interval 59 to 77) and the standardised mortality ratio for all cancers was 50 (95% confidence interval 36 to 67). There was no significant excess mortality from lymphomas or leukaemias, but 16 of the 221 deaths in anaesthetists were due to suicide, giving a standardised mortality ratio of 202 (95% confidence interval 115 to 328). When anaesthetists were compared with all doctors the standardised mortality ratio for suicide was only 114, a nonsignificant excess. These findings confirm that the risk of suicide among anaesthetists is twice as high as among other men in social class I but suggest that the risk does not differ significantly from that among doctors as a whole. There was no evidence of a significant excess risk of cancer, and, in particular, the small excess of cancer of the pancreas reported previously could not be confirmed.

Adult↗
PubMed1987

Cerebral blood flow increases during insulin-induced hypoglycaemia in type 1 (insulin-dependent) diabetic patients and control subjects.

The effect of insulin-induced hypoglycaemia on cerebral blood flow was examined using the intravenous xenon-clearance technique in 9 patients with Type 1 (insulin-dependent) diabetes (aged 20 to 43 years) and 9 age-matched control subjects before, during and after hypoglycaemia. Cerebral blood flow rose in both groups. The mean basal cerebral flood flow values were not significantly different and during hypoglycaemia mean cerebral blood flow increased by 17% (p = 0.008) in the diabetic patients and by 21% (p = 0.0003) in the control subjects. The results suggest that in young diabetic patients without autonomic neuropathy or microangiopathy cerebral vessels dilate normally in response to hypoglycaemia. The physiological importance of an increase in cerebral blood flow during hypoglycaemia is uncertain; but glucose availability is increased.

Adult↗
PubMed1986

Risk of hypothermia in elderly patients with diabetes.

The incidence of admissions of patients with hypothermia was determined to examine whether hypothermia was more common in elderly patients with diabetes than in the general population after diabetic metabolic emergency cases had been excluded. A prospective survey of three accident and emergency departments identified 134 cases of hypothermia admitted from a catchment population of almost 157,000 aged 65 or over during the winters of 1981-2 to 1983-4. The predicted number of patients with diabetes in the population was nearly 5600 (3.5%). Twenty three admissions for hypothermia (17%) occurred in 20 patients with previously diagnosed diabetes. Women made up 87% of the diabetic admissions; the ratio of diabetic to non-diabetic admission rates in women was 7.9 (95% confidence interval 5.3 to 12.0). After excluding diabetic metabolic emergency admissions the ratio was 6.4. The ratio in men was 2.4, but the small number of admissions produced wide confidence intervals. Ten of the admissions with diabetes (43%) had pathological disorders that are associated with an increased risk of hypothermia. The frequency of these conditions is higher in patients with diabetes than in the general population and partly explains the increased risk of hypothermia in these patients.

Aged↗
PubMedDate not supplied

The Oxford Community Diabetes Study: evidence for an increase in the prevalence of known diabetes in Great Britain.

A prevalence survey for known diabetes was conducted in a geographically defined population of nearly 40,100 in Oxford in April 1982. The age-adjusted prevalence rate was 10.4/1000 which did not differ significantly from age-adjusted rates of 9.5/1000 in Poole and 10.5/1000 in Southall. The prevalence increased with age and was higher in men than women over the age of 30 years. Our results confirm that there has been a change in the male to female sex ratio and suggest that there are about 500,000 diagnosed diabetics in England and Wales including about 190,000 insulin-treated patients. These findings are consistent with a secular increase in the prevalence of diagnosed diabetes over the last two decades which has important implications for the planning and provision of resources for care.

Age Factors↗
PubMedDate not supplied

Diabetic autonomic neuropathy: the prevalence of impaired heart rate variability in a geographically defined population.

The prevalence of diabetic autonomic neuropathy and its relationship with other diabetic complications were studied in a geographically defined population. Heart rate variability was measured by a computerized technique at rest and in response to both a single deep breath and a Valsalva manoeuvre. Among 43 Type 1 (insulin-dependent) and 202 Type 2 (non-insulin-dependent) patients results below the 2.5 centile for age-related normal ranges occurred in 9 Type 1 and 32 Type 2 patients (16.7, 95% Cl 12.6 to 21.9, %). Symptomatic autonomic neuropathy was uncommon but was significantly more frequent in Type 1 than Type 2 patients (5 Type 1, 1 Type 2, p less than 0.001 Fisher's exact test). In Type 1 diabetes, cardiovascular autonomic dysfunction was significantly associated with impaired vibration perception and a higher logarithmic urinary albumin concentration and, in Type 2 diabetes, it was associated with a significantly higher body mass index, systolic blood pressure, and logarithm of the urinary albumin and fasting insulin concentrations. The aggregation of these factors with cardiovascular autonomic dysfunction suggests that mortality might be increased in Type 2 patients with asymptomatic autonomic neuropathy.

Adult↗
PubMedDate not supplied

Diabetes in the elderly: the Oxford Community Diabetes Study.

Most diabetic patients are elderly but their clinical characteristics remain poorly defined. A population survey identified 259 known diabetic patients aged 60 years or more giving a prevalence of 3% in this age group. A total of 193 patients (75%) were interviewed and examined, 155 (80%) of whom had been diagnosed at under 70 years of age. Forty-two patients (22%) were insulin-treated but clinical characteristics suggested that at least 95% of all elderly patients had Type 2 diabetes. Blood glucose control was poor with median HbA1 9.7% (range 4.9-17.1%, normal reference range 5.0-7.5%), and 55% were either overweight or obese. There was a high morbidity from diabetes and other conditions: the prevalence of hypertension (untreated blood pressure of 160/95 mmHg or more or antihypertensive medication) was 52%, of stroke 5%, of nephropathy (urinary albumin concentration greater than or equal to 300 mg l-1) 3%, of lower limb amputations 4%, and of foot ulcers 7%. The prevalence of symmetrically impaired distal vibration perception was 23%, and 54% of patients either needed or were receiving chiropody. The prevalence of a corrected distant visual acuity of 6/12 or worse was 32% and of retinopathy of any degree was 26%. There was extensive co-morbidity which was not confined to a single subgroup of patients.

Adult↗