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Biomedical subjects

D Yeates

Publications and source records attributed to D Yeates.

At least 19 recordsLinked to original sources

Trends in mortality after hospital admission for liver cirrhosis in an English population from 1968 to 1999.

BACKGROUND: Population based mortality rates from liver cirrhosis, and alcohol consumption, have increased sharply in Britain in the past 35 years. Little is known about the long term trends over time in mortality rates after hospital admission for liver cirrhosis. AIMS: To analyse time trends in mortality in the year after admission for liver cirrhosis from 1968 to 1999. SUBJECTS: A total of 8192 people who were admitted to hospital in a defined population of Southern England. METHODS: Analysis of hospital discharge statistics linked to death certificate data. The main outcome measures were case fatality rates (CFRs) and standardised mortality ratios (SMRs). RESULTS: At 30 days after admission, CFR was 15.9% and the SMR was 93 (86 in men and 102 in women, compared with 1 in the general population). At one year, the overall CFR was 33.6% and SMR was 16.3. There was no improvement from 1968 to 1999 in mortality rates. SMRs were highest for alcoholic cirrhosis of the liver (27.4 at one year) but lower for biliary cirrhosis (11.4) and chronic hepatitis (10.0). Mortality from most of the main causes of death, including accidents and suicides, was increased. CONCLUSIONS: The high mortality rates after hospital admission, and the fact that they have not fallen in the past 30 years, show that liver cirrhosis remains a disease with a very poor prognosis. Increased mortality from accidents, suicides, and mental disorders, particularly among those with alcoholic cirrhoses, indicates that prognosis is influenced by behavioural as well as by physical pathology.

Adult↗

Cancer after cholecystectomy: record-linkage cohort study.

We investigated whether cholecystectomy is associated with subsequent cancer and, if so, whether the association is likely to be causal, by undertaking a retrospective cohort study using linked medical statistics, comprising a cholecystectomy group (n=39 254) and a reference cohort admitted for a range of other medical and surgical conditions (n=334 813). We found a short-term significant elevation of rates of cancers of the colon, pancreas, liver, and stomach after cholecystectomy, but no long-term elevation. Excluding colon cancers within 2 years of admission to hospital, the rate ratio for colon cancer after cholecystectomy, compared with the reference cohort, was 1.01 (95% confidence interval 0.90-1.12) and after 10 years or more follow-up it was 0.94 (0.79-1.10). It is highly improbable that the short-term associations between cholecystectomy and gastrointestinal cancers are causal, and we conclude that cholecystectomy does not cause cancer.

Adult↗

Cancer following hip and knee arthroplasty: record linkage study.

Concerns have been raised that degradation of implants used in hip and knee arthroplasty may lead to an increased risk of some cancers, particularly those of the haematopoietic, lymphatic and urinary systems. We used linked statistical records of hospital admissions and deaths to compare cancer rates in cohorts of people who had undergone hip or knee arthroplasty with a comparison cohort. We did not find an elevated risk for cancer, overall, in either the hip or knee cohort or in both combined (rate ratio for both combined 0.99; 95% confidence intervals 0.95-1.02), or for haematopoietic, lymphatic or urinary system cancers. There was also no elevation in risk of cancer more than 10 years after arthroplasty. Our findings add to the evidence that arthroplasty is safe in respect of cancer risk.

Adult↗

Trends in mortality and hospital admission rates for abdominal aortic aneurysm in England and Wales, 1979-1999.

BACKGROUND: The aim of this study was to investigate trends in population-based mortality, hospital admission and case fatality rates for abdominal aortic aneurysm (AAA) from 1979 to 1999. METHODS: This was an analysis of routine statistics from 79 495 death certificates in England and Wales and 3217 hospital inpatient admissions in the Oxford Region. RESULTS: Mortality rates for all AAAs increased between 1979 and 1999 from 13 to 25 per million in women and from 80 to 115 per million in men. Admission rates increased in the same time interval from three to 22 admissions per million per year in women, and from 52 to 149 per million per year in men. Case fatality rates for all non-ruptured AAAs that were operated on decreased from 25.8 to 9.0 per cent and for all ruptured AAAs from 69.9 to 54.4 per cent. CONCLUSION: Mortality rates and hospital admission rates for AAA rose in men and even more so in women between 1979 and 1999. Perioperative mortality for ruptured AAA declined a little during the study but nonetheless was still very high at the end. This reinforces the importance of detecting and treating AAA before rupture occurs.

Aortic Aneurysm, Abdominal↗

Cancers and immune related diseases associated with Down's syndrome: a record linkage study.

OBJECTIVE: To determine the risk of cancers and selected immune related diseases in people with Down's syndrome, relative to risk in other people. DESIGN: Cohort analysis of a linked dataset of abstracts of hospital and death records; results expressed as the ratios of rates of disease in people with and without Down's syndrome. SETTING: The former Oxford health region, England, 1963-1999. SUBJECTS: Cohort of 1453 people with Down's syndrome and cohort of 460,000 people with other conditions for comparison. MAIN OUTCOMES: As expected, the rate ratio for leukaemia was substantially elevated in people with Down's syndrome: it was 19-fold higher (95% confidence intervals 10.4 to 31.5) than the rate in the comparison cohort. For other cancers combined, excluding leukaemia, the rate ratio was not significantly elevated (1.2; 0.6 to 2.2). The risk of testicular cancer was increased (12.0; 2.5 to 35.6), although this was based on only three cases in the cohort of subjects with Down's syndrome. Significantly elevated risks were found for coeliac disease (4.7; 1.3 to 12.2), acquired hypothyroidism (9.4; 3.4, 20.5), other thyroid disorders, and type 1 diabetes mellitus (2.8; 1.0 to 6.1). A decreased risk was found for asthma (0.4; 0.2 to 0.6). CONCLUSIONS: Our data add to the body of information on the risks of co-morbidity in people with Down's syndrome. The finding on asthma needs to be confirmed or refuted by other studies.

Adolescent↗

Skin cancer in people with multiple sclerosis: a record linkage study.

OBJECTIVE: The prevalence of multiple sclerosis (MS) varies with latitude: it increases with distance from the equator in both hemispheres. To seek evidence on whether solar radiation is a protective factor for MS, this study investigated whether skin cancer, as an indicator of solar radiation, is less common in people with MS than in others. DESIGN: Analysis of a database of linked hospital records and death certificates. SETTING: The Oxford Region of the National Health Service, England. SUBJECTS: A cohort comprising all people in the database with MS, and comparison cohorts of people with other diseases. RESULTS: Skin cancer was significantly less common in people with MS than in the main comparison cohort (rate ratio 0.49; 95% confidence interval 0.24 to 0.91). There was no general deficit of cancer in the MS cohort, and no deficit of skin cancer in cohorts of people with other autoimmune or neurological diseases. CONCLUSION: The findings support the hypothesis that solar radiation may have a protective influence on the development of MS.

Adult↗

Appendicectomy, tonsillectomy, and inflammatory bowel disease: a case-control record linkage study.

STUDY OBJECTIVE: To determine whether appendicectomy and tonsillectomy are associated with ulcerative colitis (UC) or Crohn's disease (CD); and, if so, whether the associations are related to age at operation. DESIGN: Nested case-control studies using a longitudinal database of linked hospital and death record abstracts. SETTING: Southern England. PATIENTS: Statistical records of people diagnosed with UC, CD, or a control condition admitted to hospitals in a defined area. MAIN RESULTS: Appendicectomy under the age of 20 years was associated with a significantly reduced subsequent risk of UC (relative risk =0.48, 95% confidence interval 0.30 to 0.73). The association appeared strongest for appendicectomy between 10 and 14 years of age (relative risk =0.29, 95% CI 0.09 to 0.68). Appendicectomy at the age of 20 years and over was associated with an increased subsequent risk of CD (relative risk =1.92, 95% CI 1.58 to 2.32), largely confined to those people whose CD was diagnosed within a year of appendicectomy. Appendicectomy under 20 years of age, undertaken five years or more before case or control conditions, was suggestively associated with a reduced risk of CD (relative risk =0.71, 95% CI 0.47 to 1.03). Prior tonsillectomy was not associated with any increase or decrease of risk of either UC or CD. CONCLUSIONS: Appendicectomy is associated with a reduced risk of UC; and the association is specific to young age groups when the population risk of appendicitis is itself highest. The increased risk of CD after appendicectomy, at short time intervals between the two, is probably attributable to the misdiagnosis of CD as appendicitis.

Adolescent↗

Intercurrent drug therapy and perioperative cardiovascular mortality in elective and urgent/emergency surgical patientst.

The Oxford Record Linkage Study (ORLS; an epidemiological database) was used to examine relationships between intercurrent cardiovascular drug therapy and cardiac death within 30 days of elective or emergency/urgent surgery under general anaesthesia. Cases identified from the ORLS were paired with matched control patients. Clinical details were obtained from the patients' medical notes. In elective surgical patients, there was no effect of beta-adrenoceptor or calcium entry channel blockade, diuretics or digoxin on cardiac death after adjusting for confounding variables. Use of nitrates was associated with an odds ratio of 4.79 [95% confidence interval (CI) 1.01-22.72] for cardiac death after adjustment for confounding by a history of angina and residual age difference. In emergency/urgent patients, there were significant univariate associations with cardiac death for intercurrent use of angiotensin converting enzyme (ACE) inhibitors (odds ratio 1.18) and diuretics (odds ratio 4.95; 95% CI 1.82-13.46). However, neither maintained significance after adjustment for the confounding effect of cardiac failure. We conclude that, with the possible exception of the use of nitrates in elective surgical patients, chronic intercurrent drug treatment alone does not significantly affect the odds of cardiac death within 30 days of surgery.

Adrenergic beta-Antagonists↗

Depression and anxiety in people with inflammatory bowel disease.

STUDY OBJECTIVE: To determine whether depression or anxiety co-occurs with ulcerative colitis (UC) or Crohn's disease (CD) more often than expected by chance, and, if so, whether the mental disorders generally precede or follow the inflammatory bowel diseases (IBD). DESIGN: Nested case-control studies using a database of linked hospital record abstracts. SETTING: Southern England. MAIN RESULTS: Both depression and anxiety preceded UC significantly more often than would be predicted from the control population's experience. The associations were strongest when the mental conditions were diagnosed shortly before UC, although the association between depression and UC was also significant when depression preceded UC by five or more years. Neither depression nor anxiety occurred before CD more often than expected by chance. However, depression and anxiety were significantly more common after CD; the associations were strongest in the year after the initial record of CD. UC was followed by anxiety, but not by depression, more often than expected by chance and, again, the association was strongest within one year of diagnosis with UC. CONCLUSIONS: The concentration of risk of depression or anxiety one year or less before diagnosis with UC suggests that the two psychiatric disorders might be a consequence of early symptoms of the as yet undiagnosed gastrointestinal condition. The data are also, however, compatible with the hypothesis that the psychiatric disorders could be aetiological factors in some patients with UC. Most of the excess anxiety or depression diagnosed subsequent to diagnosis of IBD occurs during the year after IBD is diagnosed and the probable explanation is that the mental disorders are sequelae of IBD.

Adult↗

Hormonal and other factors in relation to survival among breast cancer patients.

We have examined the relationship between all-cause mortality and various hormonal and other factors in over 1,200 women with breast cancer recruited into 2 consecutive case-control studies between 1969 and 1984. The age at diagnosis ranged from 24 to 59 years, and the majority (74%) were pre-menopausal at diagnosis. Analyses were based on follow-up to 1 January 1994, by which time 608 (50%) of the women had died. Of the factors examined, weight was most strongly associated with survival, with a significant increase in the risk of death with increasing weight. Two hormonal factors, time since last birth and time since last oral contraceptive use, were also independently associated with survival. All of these associations remained after adjustment for stage and histological nodal status. Our findings provide new evidence to suggest that reproductive factors and exogenous hormones in the form of oral contraceptives may influence survival in women with breast cancer, even after differences in stage and nodal status have been taken into account.

Adult↗

Use of large medical databases to study associations between diseases.

We describe the use of a dataset of statistical medical records, the Oxford Record Linkage Study (ORLS), to identify diseases which occur together more commonly (association), or less commonly (dissociation), than their individual frequencies in the population would predict. We investigated some conditions known or suspected to enhance the subsequent risk of cancer, some conditions thought to be linked with schizophrenia, and some associations between conditions with a known autoimmune component. Diseases may occur in combination more often (or less often) than expected by chance because one predisposes to (or protects against) another or because they share environmental and/or genetic mechanisms in common. The investigation of such associations can yield important information for clinicians interested in potential disease sequelae, for epidemiologists trying to understand disease aetiology, and for geneticists attempting to determine the genetic basis of variation in disease course among individuals. We suggest that, through the use of datasets like the ORLS, it will be possible to 'map' comprehensively the phenomic expression of co-occurring diseases.

Case-Control Studies↗

Close genetic similarity between two sympatric species of tephritid fruit fly reproductively isolated by mating time.

Two sibling species of tephritid fruit fly, Bactrocera tryoni and B. neohumeralis, occur sympatrically throughout the range of B. neohumeralis in Australia. Isolation between the two species appears to be maintained by a difference in mating time: B. tryoni mates at dusk, whereas B. neohumeralis mates during the middle of the day. A morphological difference in humeral callus color also distinguishes the two species. Despite clear phenotypic evidence that B. tryoni and B. neohumeralis are distinct species, genetic differentiation as measured by four markers--nuclear DNA sequences from the white gene and the ribosomal internal transcribed spacer (ITS2), and mitochondrial DNA sequences from the cytochrome b (cytb) and cytochrome oxidase subunit II (COII) genes--is very small. Minor fixed differences occur in the ITS2 sequence, however, in all other cases the two species exhibit a high level of shared polymorphic variation. The close genetic similarity suggests either that speciation has occurred very rapidly and recently in the absence of any mitochondrial DNA sorting or that the sharing of polymorphisms is due to hybridization or introgression. A third species within the tryoni complex, B. aquilonis, is geographically isolated. Bactrocera aquilonis is also genetically very similar, but in this case there is clear differentiation for the mitochondrial loci. The three species form a group of considerable interest for investigation of speciation mechanisms.

Amino Acid Sequence↗

Risk factors for cardiovascular death within 30 days after anaesthesia and urgent or emergency surgery: a nested case-control study.

The Oxford Record Linkage Study (an epidemiological database) was used to identify patients who died from a cardiovascular cause within 30 days of emergency or urgent surgery under general anaesthesia. Each case was paired with a control patient (matched for age within 10 yr of the patient, operation and consultant). Additional clinical information was sought from the patient's case notes. Cases and controls were compared for cardiovascular risk factors using conditional logistic regression analysis and a prognostic model was generated. Only one significant risk factor was identified in the final model: a history of cardiac failure (odds ratio 14.84; 95% confidence intervals 2.53-87.13; P = 0.003). Associations between a history of cerebrovascular accident or renal impairment and cardiovascular mortality were seen using univariate analysis but not after adjustment for confounding factors.

Adult↗

Evolution and systematics of Anopheles: insights from a molecular phylogeny of Australasian mosquitoes.

Relationships among the genus Anopheles and its many sibling species-groups are obscure despite the importance of anophelines as the vectors of human malaria. For the first time, the interrelationships and the origin of Australasian members of the subgenus Cellia are investigated by a cladistic analysis of sequence variation within the mitochondrial cytochrome oxidase subunit II gene. Estimated divergence times between many Australasian and Oriental taxa predate the mid Miocene collision of Australasia and Southeast Asia. Phylogenetic analysis suggests that two-way exchanges with Oriental mosquitoes rather than only immigration may have been a characteristic of anopheline paleobiogeography in Australasia. The Australasian fauna is mostly included in a large clade. The medically important Punctulatus Group is monophyletic and appears derived from Oriental stock. Populations within this group from as far apart as Australia and Vanuatu were in contact in the recent past (i.e., 0.35-2.44 mya), supporting dispersal rather than vicariance explanations. Some support for the monophyly of the Myzomyia, Neomyzomyia, and Pyretophorus Series was found. However, the subgenera Anopheles and Cellia and the Neocellia Series are paraphyletic, but branch support at these taxonomic levels was poor. The COII gene shows promise for questions concerning alpha taxonomy but appears to be of limited use for resolving deeper relationships within the Anopheles.

Amino Acid Sequence↗

Risk factors for cardiovascular death after elective surgery under general anaesthesia.

A large epidemiological data set was used to identify 115 patients who died from a cardiovascular cause within 30 days of elective surgery under general anaesthesia. For each patient, a control was identified, matched for age (within 5 yr of the patient), sex, operation and consultant. Patients and controls were compared for cardiovascular risk factors in a matched analysis using conditional logistic regression, and a prognostic model was generated. Three risk factors were included in the final model: previous myocardial infarction (odds ratio 3.18 (95% confidence intervals (CI) 1.22-8.28), P = 0.018), history of hypertension (odds ratio 1.90 (0.99-3.62), P = 0.047) and renal failure (odds ratio 3.56 (1.04-12.10), P = 0.043).

Adult↗