David Yeates

The epidemiology of hysterectomy: findings in a large cohort study

Objective To examine patterns of hysterectomy in the Oxford‐Family Planning Association (Oxford‐FPA) study in relation to age, parity, social class and calendar period (–1974, 1975–79. 1980–84, 1985–89).

Risk of venous thromboembolism in people admitted to hospital with selected immune-mediated diseases: record-linkage study

BackgroundVenous thromboembolism (VTE) is a common complication during and after a hospital admission. Although it is mainly considered a complication of surgery, it often occurs in people who have not undergone surgery, with recent evidence suggesting that immune-mediated diseases may play a role in VTE risk. We, therefore, decided to study the risk of deep vein thrombosis (DVT) and pulmonary embolism (PE) in people admitted to hospital with a range of immune-mediated diseases.MethodsWe analysed databases of linked statistical records of hospital admissions and death certificates for the Oxford Record Linkage Study area (ORLS1:1968 to 1998 and ORLS2:1999 to 2008) and the whole of England (1999 to 2008). Rate ratios for VTE were determined, comparing immune-mediated disease cohorts with comparison cohorts.ResultsSignificantly elevated risks of VTE were found, in all three populations studied, in people with a hospital record of admission for autoimmune haemolytic anaemia, chronic active hepatitis, dermatomyositis/polymyositis, type 1 diabetes mellitus, multiple sclerosis, myasthenia gravis, myxoedema, pemphigus/pemphigoid, polyarteritis nodosa, psoriasis, rheumatoid arthritis, Sjogrens syndrome, and systemic lupus erythematosus. Rate ratios were considerably higher for some of these diseases than others: for example, for systemic lupus erythematosus the rate ratios were 3.61 (2.36 to 5.31) in the ORLS1 population, 4.60 (3.19 to 6.43) in ORLS2 and 3.71 (3.43 to 4.02) in the England dataset.ConclusionsPeople admitted to hospital with immune-mediated diseases may be at an increased risk of subsequent VTE. Our findings need independent confirmation or refutation; but, if confirmed, there may be a role for thromboprophylaxis in some patients with these diseases.

Depression and anxiety in people with inflammatory bowel disease.

STUDY OBJECTIVE To determine whether depression or anxiety co-occurs with ulcerative colitis (UC) or Crohns 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 populations 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.

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.

Mortality in patients with and without colectomy admitted to hospital for ulcerative colitis and Crohn's disease: record linkage studies

Objective To compare mortality outcomes in the three years after elective colectomy, no colectomy, and emergency colectomy among people admitted to hospital for inflammatory bowel disease, to inform whether the threshold for elective colectomy in clinical practice is appropriate. Design Record linkage studies. Setting Oxford region (1968-99) and England (1998-2003). Participants 23 464 people with hospital stay for more than three days for inflammatory bowel disease, including 5480 who had colectomy. Main outcome measures Case fatality, relative survival, and standardised mortality ratios. Results In the Oxford region, three year mortality was lower after elective colectomy than after either no colectomy or emergency colectomy, although this was not significant. For England, mortality three years after elective colectomy for ulcerative colitis (3.7%) and Crohns disease (3.3%) was significantly lower than that after either admission without colectomy (13.6% and 10.1%; both P<0.001) or emergency colectomy (13.2% and 9.9%; P<0.001 for colitis and P<0.01 for Crohns disease). Three or more months after elective colectomy, mortality was similar to that in the general population. Adjustment for comorbidity did not affect the findings. Conclusions In England, the clinical threshold for elective colectomy in people with inflammatory bowel disease may be too high. Further research is now required to establish the threshold criteria and optimal timing of elective surgery for people with poorly controlled inflammatory bowel disease.

Cancer in patients with motor neuron disease, multiple sclerosis and Parkinson's disease: record linkage studies

Objective To determine the risk of cancer before and after the diagnosis of motor neuron disease (MND), multiple sclerosis (MS) and Parkinsons disease (PD). Methods Analysis of statistical database of linked statistical abstracts of hospital and mortality data in an area in southern England. Results Only people with PD showed a significant difference in the overall incidence of cancer compared with controls (rate ratio (RR) 0.76, 95% CIs 0.70 to 0.82 before PD; RR 0.61, 0.53 to 0.70, after PD). RRs were close to 1 for cancer in patients after MND (0.98, 0.75 to 1.26) and after MS (0.96, 0.83 to 1.09). There were high rate ratios for malignant brain cancer (7.4, 2.4 to 17.5) and Hodgkins lymphoma (5.3, 1.1 to 15.6) in patients diagnosed with MND after cancer. In people with MS, malignant brain cancer also showed an increased RR both before hospital admission with a diagnosis of MS (3.2, 1.1 to 7.6) and after (2.4, 1.2 to 4.5). In people with PD, several specific cancers showed significantly and substantially reduced RRs for cancer, notably smoking related cancers, including lung cancer (0.5, 0.4 to 0.7, before PD; 0.5, 0.4 to 0.8, after PD) but also cancers that are not strongly smoking related, including colon cancer (0.7, 0.6 to 0.9, before PD; 0.5, 0.4 to 0.8, after PD). Conclusions People with MND, or MS, do not have an altered risk of cancer overall. There may sometimes be misdiagnosis between MND or MS and brain tumours. PD carries a reduced risk of cancer overall, of some smoking related cancers and of some cancers that are not smoking related.

Mortality in relation to oral contraceptive use and cigarette smoking

BACKGROUND As part of the Oxford Family Planning Association study, we compared mortality in relation to oral contraceptive use and smoking to highlight the differences between them from the perspective of public health. METHODS The study consisted of 17032 women, aged 25-39 years at entry, recruited between May 1, 1968, and July 31, 1974, who had used oral contraceptives, a diaphragm, or an intrauterine device. We assessed mortality from follow-up data recorded until Dec 31, 2000. The analysis is based on woman-years of observation. FINDINGS We analysed 889 deaths. Women who had ever used oral contraceptives had increased mortality from cervical cancer (rate ratio 7.2, 95% CI 1.1-303), and decreased mortality from other uterine (0.2, 0.0-0.8) and ovarian cancers (0.4, 0.2-0.7). Oral contraceptives had some adverse effect on deaths from ischaemic heart disease in women who smoked 15 or more cigarettes per day. For all causes of mortality, the rate ratio for death in women who ever used oral contraceptives was 0.89 (95% CI 0.77-1.02). By contrast, this rate ratio was 1.24 (1.03-1.49) in those who smoked one to 14 cigarettes per day, and 2.14 (1.81-2.53) in those who smoked 15 or more cigarettes per day. INTERPRETATION There was no harmful effect of oral contraceptive use on overall mortality. By contrast, death from all causes was more than twice as high in smokers of 15 or more cigarettes a day as in non-smokers. The harmful effect was already apparent in women aged 35-44 years.

Oral contraceptive use and abortion before first term pregnancy in relation to breast cancer risk.

A recent publication from California in this journal has suggested that both prolonged oral contraceptive use and abortion before first term pregnancy increases the risk of breast cancer in young women. Data are presented on 1176 women aged 16-50 years with breast cancer, interviewed in London or in Oxford, together with a like number of matches control subjects. The results are entirely reassuring, being, in fact, more compatible with protective effects than the reverse. Possible reasons for the differences between the 2 sets of data are discussed.

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.

Risk factors for gall-bladder disease: a cohort study of young women attending family planning clinics

During 1968-74, 17 032 women aged 25-39 years were recruited to the Oxford/Family Planning Association Contraceptive Study. By the end of August 1981, 227 of these women had suffered surgically confirmed gall-bladder disease during the follow-up period, an incidence of 1·47 per 1000 woman-years. Obesity was by far the strongest risk factor for gall-bladder disease, but late age at first term birth and cigarette smoking also had statistically significant independent effects. The influence of the use of oral contraceptives on risk was small.