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Objective: Anorexia nervosa (AN) and bulimia nervosa (BN) are eating disorders associated with high rates of self‐harm (SH). This is the first national study in England to quantify this association in a hospital population. Method: A retrospective cohort study using a linked national dataset of Hospital Episode Statistics for 1999–2021. The exposure cohort included individuals aged <35 years admitted to hospital with a diagnosis of AN or BN. The reference cohort included hospital controls. We calculated the rate ratio (RR) of SH in each cohort. The individuals in the two cohorts were matched on multiple socio‐demographic indicators. The main outcome was a subsequent hospitalization or death record with an SH diagnosis. Results: We identified 15,004 females and 1411 males with AN, and 6055 females and 741 males with BN. The RR with 95% confidence intervals (95%CI) for a subsequent admission with intentional self‐harm after admission with AN was 4.9 (95%CI 4.7–5.1) in females and 4.8 (95%CI 3.9–5.8) in males. For BN it was 9.0 (95%CI 8.4–9.6) in females and 9.8 (95%CI 7.7–12.2) in males. There were strong associations between AN and BN and other SH. Discussion: Women and men admitted to English hospitals with AN or BN have a very high risk of a subsequent admission with SH. For some SH behaviors, such as alcohol intoxication, the RR was >10‐fold elevated. The magnitude of risk was higher for BN than for AN. Clinicians should be aware of the scale of risk increase. Providing those at risk with appropriate support is required. Public significance: This study is the first national study in an English hospital population that confirms and quantifies the association between eating disorders and self‐harm. We have found that both women and men admitted to hospital with anorexia nervosa or bulimia nervosa are at an increased risk of subsequent admission with self‐harm. It is important that clinicians are aware of this increased risk to support those at highest risk of self‐harm. [ABSTRACT FROM AUTHOR]

Aims: Non-specific abdominal pain (NSAP) is the most common diagnosis on discharge following admission for abdominal pain in childhood. Our aim was to determine the risk of subsequent hospital diagnosis of organic and functional gastroenterological conditions following a diagnosis of NSAP, and to assess the persistence of this risk.Methods: An NSAP cohort of 268,623 children aged 0-16 years was constructed from linked English Hospital Episode Statistics from 1999 to 2011. The control cohort (1,684,923 children, 0-16 years old) comprised children hospitalised with unrelated conditions. Clinically relevant outcomes were selected and standardised rate ratios were calculated.Results: From the NSAP cohort, 15,515 (5.8%) were later hospitalised with bowel pathology and 13,301 (5%) with a specific functional disorder. Notably, there was a 4.84 (95% CI 4.45 to 5.27) times greater risk of Crohn's disease following NSAP and a 4.23 (4.13 to 4.33) greater risk of acute appendicitis than in the control cohort. The risk of irritable bowel syndrome (IBS) was 7.22 (6.65 to 7.85) times greater following NSAP. The risks of inflammatory bowel disease (IBD), IBS and functional disorder (unspecified) were significantly increased in all age groups except <2-year-olds. The risk of underlying bowel pathology remained raised up to 10 years after first diagnosis with NSAP.Conclusions: Only a small proportion of those with NSAP go on to be hospitalised with underlying bowel pathology. However, their risk is increased even at 10 years after the first hospital admission with NSAP. Diagnostic strategies need to be assessed and refined and active surveillance employed for children with NSAP. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to study trends over time in operation rates for inguinal hernia with and without obstruction over five decades.Methods: Routine hospital statistics were used to analyse trends in National Health Service hospitals in England (1968-2011).Results: All-England admission rates for elective repair of unobstructed inguinal hernia in males were 240.8 episodes per 100,000 population [95 % confidence interval (CI) 234.5-247.2] in 1968 and were relatively stable until 2003 after which they declined to 217.1 (215.4-218.8) by 2011. However, the stability of the all ages rates masked a large decline in admission rates in the young (e.g. 425 per 100,000 in 1968-1970 in males under 1 year of age, down to 155 per 100,000 in 2007-2011) and a large increase in the elderly (e.g. 247 in 1968-1970 per 100,000 males aged 75-84, up to 799 per 100,000 in 2007-2011). All-England admission rates for obstructed inguinal hernia in males almost halved, from 19.3 episodes (17.4-21.2) in 1968 to 10.7 episodes (10.3-11.0) per 100,000 population in 2011. Admission rates for females gradually declined over time for both unobstructed and obstructed inguinal hernia.Conclusion: Hospital admission rates for elective operation on inguinal hernia without obstruction, for all ages combined, have been relatively stable over five decades, but this masked big differences between age groups. Rates of obstructed hernia have declined over time, particularly in the early years covered by the study, and have not shown an increase associated with the recent fall in elective surgery for hernia repair. [ABSTRACT FROM AUTHOR]

Background Historically, many women with intellectual disability ( ID) did not have children. However, a few decades ago it became more common for women with ID to give birth. Our aim was to compare the completed pregnancies of mothers with ID with other completed pregnancies in a large, defined population. Methods We used the archived dataset of the Oxford record linkage study from 1970 to 1989, which included a specialized dataset of all maternities in a population of 850 000 people. Results There were 245 007 births, of which 217 were to mothers with a record of ID. Mothers with a record of ID were more likely than others to give birth at a young age, were much more likely to be unmarried (42% compared with 9%) and to have smoked in the pregnancy (54% compared with 23%). Comparing babies born of mothers with ID and others, percentages with very low birth weight (<2000 g) were similar at 1.9 and 1.8%. There was no excess of babies who were low birth weight for gestational age. Babies born of mothers with ID were much less likely than others to be breastfed (respectively, 33 and 70%). There were no significant associations with presentation at delivery, Caesarean section or forceps delivery. The distribution of Apgar scores at 1 min after birth was similar in babies of mothers with ID and other babies. The sex ratio of the babies was normal. Combining stillbirths and infant deaths, rates per 1000 were 27.9 for babies of mothers with ID and 13.4 in other babies (borderline significant at P = 0.07). Conclusions Comparing pregnancies and outcomes of mothers with and without ID, there are some important differences, and some important similarities. It is possible, however, that there may be differences over time and between different places in the care and outcomes of pregnancies in mothers with ID. In the modern era, with electronic health records, it should be possible for maternity services, both locally and on a whole population basis, routinely to monitor the pregnancies, and their outcomes, of mothers with ID. [ABSTRACT FROM AUTHOR]

Objective To quantify the extent of 'avoidable mortality' in those with schizophrenia or bipolar disorder and to quantify the effect a reduction in these might have on the mortality gap associated with severe mental illness. Method A cohort was studied of people aged <75 years, discharged from inpatient care with schizophrenia or bipolar disorder in 2006-2007, and followed up for 365 days. Standardised mortality ratios ( SMRs) were calculated followed by hypothetical SMRs, estimating the residual mortality gap if 'avoidable' causes and suicide in the cohorts had occurred at the same level as those in the general population. Results Avoidable deaths comprised 60.2% and 59.2% of all deaths in the schizophrenia and bipolar disorder cohorts respectively. All-cause SMRs were 4.23 (95% CI 3.85-4.60) and 2.60 (2.21-3.00) respectively. After discounting the excess attributable to avoidable causes and suicide, the SMRs fell to 2.38 (2.09-2.66) and 1.66 (1.35-1.98) respectively. Conclusion Bringing mortality from avoidable causes and suicide down to general population levels would reduce the overall mortality excess in severe mental illness substantially, by about 50%, but would not eliminate it. Other underlying factors beyond those conventionally considered as 'avoidable' need further research. [ABSTRACT FROM AUTHOR]

Background Benign breast disease (BBD) increases the risk of breast cancer, but details of the relationship would benefit from further study in the UK. Methods Analysis of linked statistical abstracts of hospital data, including a cohort of 20 976 women with BBD in an Oxford data set and 89 268 such women in an English national data set. Results Rate ratios (RRs) for breast cancer, comparing BBD and comparison cohorts in these two data sets, were 2.3 (95% CI: 2.2–2.5) and 3.2 (3.0–3.3), respectively. RRs rose with increasing age at BBD diagnosis and remained elevated for at least 20 years after diagnosis. RRs were particularly high for a relatively small number of cancers occurring in the first few months after BBD diagnosis. Conclusions Our findings accord well with those in other large studies, mostly done in the USA, in showing a sustained long-term cancer risk after BBD. They also demonstrate that known long-term risks of disease can be reliably identified from linked routine administrative hospital statistics. Most other studies omit cancers in the first few months after BBD. Such cases—presumably either misdiagnosed or miscoded—merit further study to determine whether in fact they include diagnoses of cancer that were initially missed. [ABSTRACT FROM PUBLISHER]

AimsRates of glaucoma surgery have declined in North America and continental Europe in recent years. The aim of this study was to examine trends over time and regional variation in rates of trabeculectomy in England.MethodsThe hospital in-patient enquiry (HIPE), hospital episode statistics (HES), and the Oxford record linkage study (ORLS) were analysed for annual trabeculectomy admissions between 1976 and 2004.ResultsAnnual rates of admission for trabeculectomy rose 10-fold from 1976 to 1995: from 3.7 (95% confidence intervals 3.5–3.9) admissions per 100 000 population in 1976 to a peak of 38.7 (38.1–39.3) in 1995. Admission rates then declined sharply and have begun to reach a plateau at around 10.6 (10.3–10.9) in 2004. The highest surgical rates during the period 1997–2004 were found in the 80- to 84-year-old age group. Geographical analysis showed wide variation across local authority areas in annual rates of trabeculectomy, from 4 (2.3–5.2) to 33 (29.0–36.5) people per 100 000 population in 1998–2004. The rate of surgery by local authority showed little or no association with the level of social deprivation in each area.ConclusionsThe rate of patients undergoing trabeculectomy increased substantially over 20 years. This was followed by a profound reduction in rates of trabeculectomy from 1995, which coincides with the introduction of new topical medications to reduce intraocular pressure. Wide regional variation in rates of trabulectomy was found, but there was no evidence of reduced access to glaucoma surgery in deprived areas.Eye (2009) 23, 1141–1149; doi:10.1038/eye.2008.195; published online 11 July 2008 [ABSTRACT FROM AUTHOR]

Background: Differences between women and men in treatment and outcome after admission with a ruptured abdominal aortic aneurysm (AAA) in England were studied. Methods: Routinely collected data in Hospital Episode Statistics, linked to death records, for emergency admissions for ruptured AAA in England were analysed. The percentage of patients who underwent surgical repair was calculated, together with 30-day case fatality rates and age-adjusted odds ratios (ORs), comparing women with men. Results: A total of 2463 women and 7615 men were admitted with a primary diagnosis of ruptured AAA (mean age 79.8 and 74.9 years respectively); 39.6 per cent of women and 66.4 per cent of men underwent surgical repair (OR 0.47 (95 per cent confidence interval 0.42 to 0.52)). Overall, 75.6 per cent of women and 61.7 per cent of men died within 30 days of admission (OR 1.36 (1.22 to 1.52)). The death rate for women and men who had surgery was similar (OR 1.01 (0.88 to 1.17)); when no operation was performed the mortality rate was higher in women, but not significantly so (OR 1.14 (0.91 to 1.42)). Conclusion: Women with a ruptured AAA were less likely to be treated surgically than men, and their overall mortality rate was higher. Lower rates of surgery in women than in men may contribute to the higher mortality in women, but other explanations are possible. [ABSTRACT FROM AUTHOR]

Aims To report on associations between perinatal factors and the subsequent development of diabetes mellitus under the age of 30 years in the offspring. Methods Analysis of linked hospital statistical records, comparing perinatal factors relating to the birth of 518 people admitted to hospital for diabetes with the same factors in 292 845 others, in a defined population in southern England from 1963 to 1999. Results Diabetes mellitus was much more common in children of mothers with diabetes than in others (odds ratio 6.42; 95% confidence interval 4.18–9.86). There was no significant association with birthweight or gestational age separately. Diabetes was more common in those in the highest quintile of ‘birthweight for gestational age’ compared with the lowest four quintiles combined (odds ratio 1.33; 95% confidence interval 1.08–1.64), but there was no consistent gradient of increasing frequency of diabetes across the lowest four quintiles. There were no significant associations between diabetes and mothers’ age, parity, social class, or smoking during pregnancy, or between babies’ mode of delivery or any other perinatal factors investigated. All results were similar when the analysis was confined to diabetes in people aged < 15 years. Conclusions We found a strong association between diabetes in the child—mainly, if not entirely Type 1 diabetes—and maternal diabetes. Diabetes was slightly more common in the heaviest quintile of birthweight for gestational age than in other quintiles. There were no significant associations between diabetes and the other perinatal factors studied. [ABSTRACT FROM AUTHOR]

Study objectives: To study the hospitalised incidence of Crohn's disease (CD) and ulcerative colitis (UC) from 1979 to 1998; and to determine whether the introduction of the measles vaccination programme was associated with an increase in the young. Design: Analysis of linked data on hospital admissions; a cohort analysis of the effect of the measles vaccination programme on the incidence of hospitalised CD and UC; and a comparison of these results with those from previous studies on the association between measles vaccine and CD or UC. Settings: Southern England. Subjects: People admitted to hospital with a main diagnosis of CD (1959 people) or UC (2018 people). Main results: Overall, the incidence of hospitalised CD showed no significant change over the 20 year period: the average change per year was 0.08% (95% confidence interval: -0.7% to 0.9%). The relative risk associated with the measles vaccination programme was not significant (0.91: 0.5 to 1 .4). The estimate differed significantly from the relative risk of 3.0 obtained in the original study reporting an association, but agreed with the combined estimate from three subsequent studies (0.95: 0.6 to 1 .5). The results for UC were similar. Conclusions: The incidence of hospitalised CD and UC remained stable over the 20 years, 1979 to 1998. Whatever caused the marked increases in CD and UC in the mid-20th century must itself have stabilised in this region. These results, together with those from other studies, provide strong evidence against measles vaccine causing CD or UC. [ABSTRACT FROM AUTHOR]

Using data from the Oxford Record Linkage Study (ORLS), we conducted a case-control study to examine prenatal risk factors for cryptorchidism. We identified 1449 boys born during 1970-86 for whom there was a record of an orchidopexy during 1970-87. Up to eight controls were matched to each case on year of birth and hospital or place of delivery. For each boy and his mother we extracted abstracts of maternity and general hospital records from the ORLS. Low birthweight (trend P < 0.001), low social class (trend P < 0.001), breech presentation (relative risk 1.67; 95% confidence interval [CI] 1.16, 2.41), pre-eclampsia (1.17 [1.00, 1.37]), artificial feeding (1.22 [1.04, 1.45]) and episiotomy (1.13 [1.00, 1.27]) were identified as independent risk factors for cryptorchidism. Gestational age was not independently associated with cryptorchidism after adjusting for birthweight (P = 0.33), and this observation suggested that some cryptorchid boys may have suffered from intrauterine growth retardation. Low birthweight, breech presentation and pre-eclampsia may have in common poor placental function and impaired fetal growth, which may be causes of cryptorchidism. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented regarding the study on the number and rate of episodes of trabeculectomy in England in which data were analyzed using the operation code C60.1 in operating procedure code supplement (OPCS) 4.

Objectives: To report on population-based epidemiological trends in central nervous system (CNS) abscesses and empyemas in England over five decades., Methods: Trend analyses of age-sex-specific hospital admission and death rates using routinely collected English national hospital discharge records, mortality records, and annual population denominators from 1968 to 2019., Results: Hospital admission rates for CNS abscesses and empyemas were stable in England until the late 1980s. In the last two decades of the study period (1999-2019), first-time admissions increased from 1.24 per 100,000 population in 1999 (95% confidence interval [CI] 1.14-1.35) to 2.86 in 2019 (95% CI 2.72-3.01). Admission rates were highest among infants and older adults, and were higher for males than females. There were small but significant increases in annual mortality rates for CNS abscesses and empyemas over the last two decades of the study period after accounting for population ageing, but mortality remained low at around 0.1-0.2 per 100,000 population. Mortality increased with advancing age; deaths in childhood were extremely rare. Case fatality rates where a relevant diagnosis was recorded as either the underlying or contributing cause were 4.3% and 9.7% respectively., Conclusions: The increase in CNS abscesses and empyemas in England might reflect improved case ascertainment, but the likelihood of a true rise in incidence should be considered., Competing Interests: Declaration of Competing Interest The authors declare no financial or commercial conflict of interest., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Aims: Mortality rates for coronary heart disease (CHD) have declined substantially in developed countries. Diabetes mellitus is an important risk factor for CHD; its prevalence is increasing. We aimed to compare trends in population-based mortality for CHD without diabetes on the death certificate with trends for CHD with diabetes on the same certificate., Methods: Analysis of an all-England dataset with multiple-cause coded mortality records from 1995 to 2010. Analysis of a similar dataset for Oxford, because it has the longest run of multiple-cause coded mortality in England, from 1979. Age-specific and age-standardized mortality rates were calculated., Results: In the all-England dataset, there were 1 772 760 deaths with CHD and no mention of diabetes; and 173 184 deaths with CHD and diabetes on the same death certificate. Of deaths with CHD without a mention of diabetes, rates per million men fell by more than half from 2843 (95% confidence interval: 2822-2862) in 1995 to 1379 (1366-1391) in 2010; and those in women halved from 1324 (1314-1336) to 628 (621-635). Of deaths with CHD and diabetes, rates per million men increased from 194 (188-200) to 215 (210-220); and those for women fell, but only very slightly, from 114 (111-118) to 101 (98-104). The longer run in Oxford, from 1979, showed that rates in men and women without diabetes had fallen by two-thirds; but that rates for CHD with diabetes had not fallen., Conclusions: The fall in mortality from CHD without diabetes has been spectacular. There has been no comparable fall in mortality from CHD with diabetes., (© 2015 The Authors. Diabetic Medicine © 2015 Diabetes UK.)

Background: Young women with neurofibromatosis type 1 (NF1) are reported to have a higher risk of breast cancer than others, and this might have implications for screening programmes. Our aim was to calculate this risk., Methods: An all-England linked data set of hospital admissions and deaths was analysed to determine age-specific rates of breast cancer in women with NF1 and controls., Results: The age-specific excess risk of breast cancer, comparing the NF1 cohort with the control cohort, was elevated 6.5-fold (95% confidence interval 2.6-13.5) in women aged 30-39 years. There was a 4.4 (2.5-7.0) times higher risk among women aged 40-49., Conclusions: Women with NF1 develop breast cancer at younger ages than the general population.

Background: Overt hypothyroidism and thyrotoxicosis have widespread systemic effects and are associated with increased mortality. Most death certificates that include them do not have the thyroid disease coded as the underlying cause of death., Aim: To describe regional (1979-2010) and national (1995-2010) trends in mortality rates for acquired hypothyroidism and thyrotoxicosis, analysing all certified causes of death (termed 'mentions') and not just the underlying cause., Design: Analysis of death registration data., Methods: Analysis of data for the Oxford region (mentions available from 1979) and English national data (mentions available from 1995). The data were grouped in periods defined by different national rules for selecting the underlying cause of death (1979-83, 1984-92, 1993-2000 and 2001-10) and were also analysed as single calendar years., Results: Mentions mortality for acquired hypothyroidism in the Oxford region declined significantly from 1979 to 2010: the average annual percentage change (AAPC) was -2.6% (95% confidence intervals -3.5, -1.8). Most of the decrease occurred during the 1980s. The AAPC in rates for later years in England (1995-2010) was non-significant at 0.2% (-0.7, 1.0). Mortality rates for thyrotoxicosis decreased significantly: the AAPC was -2.8% (-4.1, -1.5) in the Oxford region and -3.8% (-4.7, -3.0) in England. In England, between 2001 and 2010, hypothyroidism or thyrotoxicosis was coded as the underlying cause of death on, respectively, 17 and 24% of death certificates that included them., Conclusion: Mortality rates for hypothyroidism and thyrotoxicosis have fallen substantially. The fall is probably wholly or mainly a result of improved care.

Objective: To report on trends in mortality for asthma using all certified causes of death mentioned on death certificates (conventionally termed 'mentions'), not just the underlying cause., Study Design: Retrospective analysis using death certificate information and population data., Method: Analysis of mortality records in the Oxford region (mentions available from 1979 to 2007) and English national data (mentions available from 1995 to 2007). The data were considered in periods defined by different national rules for selecting underlying cause of death (1979-1983, 1984-1992, 1993-2000, 2001-2007), and were also analysed as single calendar years., Results: In Oxford, underlying cause mortality rates per million population in the four periods were 25, 32, 22 and 15, respectively. Rates for mentions were 44, 47, 41 and 29, respectively. Rule changes exaggerated the increase in underlying cause mortality in 1984-1992 (when 67% of asthma deaths were coded as underlying cause). Conversely, the decrease in underlying cause mortality for asthma by 2001-2007 is less than it seems (because just under 50% of asthma deaths in 2001-2007 were coded as underlying cause). Comparisons of trends in asthma and chronic obstructive airways disease (COPD) for individuals aged ≥ 55 years showed a decrease for both asthma and COPD in men; in women, a decrease in asthma and an increase in COPD was seen from the early 1990s., Conclusions: Approximately half of all deaths certified for asthma are missed when asthma mortality is analysed using underlying cause alone. The long-term decreasing trend in asthma mortality is real, and is not attributable to a trend in transferring certification from underlying to contributing cause. Nonetheless, caution is needed when comparing asthma deaths using underlying cause alone across periods that include changes to rules for the selection of underlying cause., (Copyright © 2012 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.)

Objective: To report on trends in mortality and incidence for uterine cancer in England, 1985-2008., Design: Database analysis., Setting: England., Population: Data sets of English national mortality and cancer registration statistics., Methods: Analysis of data from death certificates with a mention of malignant neoplasm of corpus uteri or malignant neoplasm of uterus without specification of part, and analysis of incidence data from cancer registries in England., Main Outcome Measures: Age-adjusted and age-specific trends in rates., Results: Mortality rates in the UK declined from 41.3 per million women in 1985 until about 1999 (30.0 per million), and then increased to 35.9 per million in 2008. Incidence rates for those aged 55 years and over showed little or no change from 1985 to the early 1990s, but then increased: for example, for women aged 60-64 years, the rates per million women in 1985, 1993, 2001 and 2008 were, respectively, 448, 461, 647 and 728. Rates for younger women showed a decline, followed by an increase: for example, for women aged 50-54 years the corresponding rates were 290, 254, 267 and 294. Over the period 2001-2008, the age-adjusted average annual percentage increase was 2.55% per annum (95% CI 2.13-2.98%). The increase in incidence rates, observed from the 1990s, preceded the increase in mortality by about 10 years., Conclusions: After many years of declining rates, uterine cancer has become more common in the first decade of this century. One possible contributor to this increase may be an association with the increase in body mass index in women, but other causes are possible and are discussed., (© 2011 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2011 RCOG.)

Setting: Analysis of data sets that included both underlying and all contributing causes of death (together termed 'mentions'): the Oxford Record Linkage Study, 1979-2008, and England national data, 1995-2008., Objective: To determine mortality trends for the granulomatous lung conditions tuberculosis (TB) and sarcoidosis in the Oxford region (1979-2008) and England (1995-2008)., Results: Mortality for mentions of TB in the Oxford region declined from 39.7 deaths per million population in 1979 to 9.0 in 2008. The corresponding rates for underlying cause were 17.1, falling to 4.5. In England, mortality rates from TB fell from 18.5/million in 1995 to 12.2 in 2008 (mentions), and from 9.3 in 1995 to 6.5 in 2008 (underlying cause). Numbers of deaths from sarcoidosis in Oxford were very small, and showed no significant trend. For the much larger England population, mortality rates based on mentions were 3.6/million in 1995 and 4.2 in 2008; the corresponding rates for sarcoidosis as underlying cause were 2.1 and 2.3., Conclusion: TB mortality is still declining in England, despite a recent resurgence in the prevalence of the disease. Mortality from sarcoidosis has been largely stable. The conventional statistic of underlying cause of death missed almost half of all certified TB and sarcoidosis deaths.

Objective: To report on seasonal variation in hospital admissions for traffic injuries to car and truck occupants, motorcyclists, cyclists, and pedestrians., Methods: Descriptive study of hospital admission statistics in England, 1999-2004., Main Outcome Measures: national average monthly admissions for injury; severity of injury, defined as death in hospital or a hospital admission lasting four days or more., Results: Admissions for car occupants were highest in the winter months but seasonal variation was not great (highest and lowest months: December, 16% above monthly average; June, 5% below). There was a summer peak and winter trough in admissions for adult cyclists (June, 34% above average; December, 27% below) and motorcyclists (August, 33% above average; January, 43% below). Admissions for child pedestrians were highest in late spring and lowest in mid-winter (May, 24% above average; December, 28% below). By contrast, admissions for adult pedestrians were higher in winter than summer (December, 33% above average; July, 17% below). From April to September, there were more admissions for pedestrians and cyclists in England (44 875 in the six years of the study) than for car occupants (34 582). For cyclists, proportionally more injuries in the winter months were severe. Severity of injuries to car occupants did not show seasonal variation., Conclusions: The public health "toll" of traffic injuries, measured as total numbers of people injured, varies substantially by season. Although it is important to reduce all injuries, the safety of pedestrians and cyclists, as unprotected road users, needs particular attention.

Aim: To describe trends over time and geographical variation in rates of vitreo-retinal surgery in England from 1968 to 2004., Methods: Routinely collected hospital statistics were analysed for England, using the Hospital In-patient Enquiry and Hospital Episode Statistics from 1968 to 2004, and for the Oxford National Health Service Region using the Oxford Record Linkage Study from 1963 to 2004., Results: Annual admission rates in England for surgery were about 5 episodes per 100 000 population in the 1960s, rising gradually to about 10 per 100 000 in the early 1990s, and then more sharply to 30 by 2004. The Oxford Record Linkage Study shows that multiple admissions per person were rare, which confirms that the observed increase represents a real increase in the number of people treated. Annual rates in England for buckle procedures declined to about 6 episodes per 100 000 population in 2004, whereas vitrectomy surgery rose to about 26 episodes per 100 000 population in 2004., Conclusion: Vitreo-retinal surgery has developed over the last 40 years in England, rapidly so over the past 15 years. Vitrectomy surgery has become much more common in England and buckle surgery has shown a steady decline. We demonstrate statistically significant geographical variation in the current annual rate of surgery between local authorities in England.

Infection with Epstein-Barr virus (EBV) followed by infectious mononucleosis (IM) is now considered to be a risk factor for Hodgkin's disease (HD). It is less clear whether EBV infection and IM are associated with an increased risk of cancer generally. We used a longstanding record-linkage dataset in Oxford (years 1963-1998), and a more recent record-linkage dataset covering England (1999-2005), to compare rate ratios for cancer between people admitted to hospital for IM and a reference cohort. In the Oxford cohort, there was an increased risk of subsequent HD [rate ratio (RR) 6.0, 95% confidence interval (CI) 2.4-12.5] but not of other cancers combined (RR 0.85, 95% CI 0.57-1.23). In the England cohort, there were increased risks of HD (RR 3.2, 95% CI 1.2-7.0), non-Hodgkin's lymphoma (RR 5.6, 95% CI 2.9-9.8), and oropharyngeal cancer (RR 5.4, 95% CI 1.1-16.2), but no significant overall risk of cancer when lymphomas were excluded (RR 1.01, 95% CI 0.71-1.41). We confirm an association between IM and lymphoma; but the risk, if any, of cancer more generally is likely to be small.

The mechanisms that cause susceptibility to invasive meningococcal disease are largely unknown, but are likely to have important genetic and immunological components. We postulated that susceptibility to meningococcal disease might be associated with altered risks of development of other clinical disease. We studied cancer and immune-mediated disease in people who have been hospitalized with meningococcal disease. In cohorts of people who had invasive meningococcal disease, compared with reference cohorts, the rate ratio for cancer in an Oxford dataset studied from 1963 to 1998 was 0.88 [95% confidence interval (CI) 0.42-1.61] and in an all-England dataset studied from 1999 to 2005 it was 1.02 (95% CI 0.80-1.27). The respective rate ratios for immune-mediated disease were 1.49 (95% CI 0.81-2.50) and 0.69 (95% CI 0.53-0.89). Susceptibility to meningococcal disease was not associated with an altered risk of cancer. Occurrence of immune-mediated disease was, if anything, low in the large all-England cohort of people who had meningococcal disease.

Background: Regional studies in the UK indicate that the incidence of acute pancreatitis increased from the 1940s to the 1990s, while case fatality fell until the 1970s but has levelled-off since., Aims: To establish incidence and case fatality for acute pancreatitis in England from 1998 to 2003, to study geographical variation and recent trends in incidence and to study associations with social deprivation and alcohol consumption., Methods: Use of national record linkage of in-patient and mortality data for 52 096 people., Results: Overall incidence was 22.4 per 100 000 population, increasing by 3.1% annually, with largest increases for women aged under 35 years (11% per year) and for men aged 35 to 45 (5.6%). Incidence was higher in northern regions than in southern regions and in areas with high social deprivation and binge drinking. Case fatality was 6.7% at 60 days, higher for alcoholic than gallstones aetiology and was associated with social deprivation and geography., Conclusions: Acute pancreatitis is a growing problem in England, particularly among younger women. The findings indicate strongly that alcohol consumption is the main reason for recent increases in incidence, the higher incidence in socially-deprived areas and for the lack of recent improvement in prognosis.

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.

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.

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.

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.

Aims: Mortality statistics have customarily been coded and analysed using only one underlying cause of death. Rules for selecting the underlying cause, when more than one cause is certified on a death certificate, have changed twice in England over the past 20 years. We used data from death certificates for 1979-99 to compare mortality rates for diabetes mellitus certified anywhere on death certificates with those certified as the underlying cause., Methods: Analysis of data from 18,917 death certificates that included diabetes mellitus in the former Oxford health region., Results: Based on the underlying cause of death, mortality rates for diabetes varied substantially between the periods defined by rule changes. Based on mentions of diabetes anywhere on the death record, mortality rates were almost unchanged over time: they showed a non-significant rise of 0.1% per year (95% confidence interval -0.3, 0.6). Circulatory diseases were certified causes of death in 71% of all deaths in people with diabetes. Although mortality rates from circulatory diseases in the general population fell by 2.5% per year, rates for circulatory diseases in combination with diabetes did not fall., Conclusions: Two explanations are possible for the lack of change in mortality rates for diabetes based on all certified mentions between 1979 and 1999. Increasing prevalence and improved survival may have resulted in no net change; and/or there may have been no improvement in survival for people whose diabetes is associated with life-threatening pathology and in particular with circulatory diseases., (Copyright 2004 Diabetes UK)

In compiling official mortality statistics, rules for selecting the underlying cause of death have changed twice in the last 20 years in England. Mortality statistics for most types of cancer were not greatly affected, but there were significant effects on coding for cancers of colon, liver, breast, prostate, testis and bladder, and for lymphoma and leukaemia.

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.

We studied childhood cancer incidence in a population-based twin cohort using record linkage to the National Registry of Childhood Tumours. After correcting for mortality, an incidence deficit was observed (Standardized Incidence Ratio (SIR) 79; 95% Confidence Interval (CI) 39-120). Pooled analysis with data from published cohort studies indicates a similar significant incidence reduction (SIR 81, 95% CI 67-96). Further studies are warranted., (Copyright 2001 Cancer Research Campaign.)

Using data from the Oxford Record Linkage Study (ORLS), we conducted a case-control study to estimate the sex-specific risks of inguinal hernia in siblings of children with this condition. There were 1921 male and 347 female cases born during 1970-86 who were operated on for inguinal hernia at ages 0-5 years during 1970-87, with 12,886 male and 2534 female control subjects. The relative risk of inguinal hernia was 5.8 [95% confidence interval 4.0-8.4] for brothers of male cases and 4.3 [2.1-8.7] for brothers of female cases (both relative to brothers of control subjects). The relative risk was 3.7 [1.8-7.9] for sisters of male cases and 17.8 [6.9-46.3] for sisters of female cases (both relative to sisters of control subjects). The pattern of sex-dependent risks, particularly the large risk for sisters of female cases, suggests a multifactorial threshold model for the disease. Girls have much lower rates of inguinal hernia than boys, and if these rates are low because of a low susceptibility to disease due to the absence of a sex-related risk factor, then those girls who develop disease might have a potentially large contribution to susceptibility from genetic or intrauterine risk factors unrelated to sex.

Background: Using data from the Oxford Record Linkage Study (ORLS) we conducted a case-control study to examine pre-natal and early life risk factors for childhood and adolescent onset diabetes mellitus., Methods: We identified 160 boys and 155 girls born 1965-1986 and admitted to hospital with a diagnosis of diabetes during 1965-1987 in the ORLS area. Up to eight controls were matched to each case on sex, year of birth and hospital or place of birth. We linked the hospital records for each child to all of that child's hospital records and to his or her mother's maternity record., Results: There were no significant associations between subsequent diabetes and birthweight, gestational age, birthweight for gestational age, maternal age and parity. There were increased risks with not breastfeeding (relative risk [RR] = 1.33; 95% CI: 0.76-2.34), and with diabetes recorded in the mother during pregnancy (RR = 5.87; 95% CI : 0.90-38.3), but these were not statistically significant. There was a significantly raised risk with pre-eclampsia or eclampsia during pregnancy (RR = 1.48; 95% CI: 1.05-2.10)., Conclusions: Pre-eclampsia may be the result of an immunogenetic incompatibility between mother and fetus, and this early immunological disturbance might be related to incidence of diabetes in later life.

Objective: To study hospital admission rates for fractures of the proximal femur over a period when incidence is reported to have increased, compensating for known lack of precision in coding, excluding nonemergency admissions and transfers, and modelling for age, period, and cohort effects., Design: Validation of coding of a sample of hospital admissions followed by study of two sets of routinely collected statistical abstracts of hospital records; graphical analysis and statistical modelling were used to search for period and cohort effects., Setting: Oxfordshire and west Berkshire in 1968-86, covered by the Oxford record linkage study (ORLS), and ENGLAND in 1968-85, covered by the hospital inpatient enquiry (HIPE). The ORLS and HIPE datasets are almost independent (ORLS contributed about 1.8% of the HIPE data)., Subjects: Records of patients aged 65 and over., Outcome Measures: Admission rates for fractured neck of femur and fracture of other and unspecified parts of femur (N820 and N821), and evidence of period and cohort effects., Results: The validation study indicated that it was important to combine the codes 820 and 821 in this age group. Admission rates increased over the period studied in both HIPE and ORLS datasets. In HIPE the pattern was of two plateaux separated by a period of rapid rise in the late 1970s. In the ORLS data there was a more steady rise. Statistical analysis showed significant period and cohort effects but much of this was attributable to the component of the model common to both period and cohort effects (termed "drift")., Conclusions: The finding that admission rates increased in both datasets, combining relevant codings and restricting analysis to emergency admissions, strongly suggests that the rise was real. At least part of the period effect in the HIPE data, however, might be attributable to a sampling artefact. The cohort effect in incidence rates of femoral fracture has not been previously shown and would be compatible with a number of aetiological hypotheses.

Background: Inguinal hemia repair is one of the most common operations undertaken in routine surgical practice. It generally carries a very low risk of major adverse sequelae. We analysed profiles, separately, for elective and emergency operations to report on the incidence and major adverse outcomes of inguinal hernia repair in a geographically defined population., Methods: Age- and sex-specific hospital admission rates, emergency readmission rates within 30 days of discharge, and mortality rates, separately for elective and emergency operations, were calculated for the period 1976-1986 in the Oxford Record Linkage Study (ORLS) area., Results: In all, 30,675 inguinal hernia repairs were performed in the area, an all-ages annual incidence of 13 per 10,000 population. Some 9% of patients underwent operation in an emergency admission. Elective operation rates remained constant over time. Emergency repairs decreased significantly over time in males. Patients who underwent emergency repair were older, had higher emergency readmission rates than those undergoing elective repair, and had significantly elevated postoperative mortality rates. In those who died it was uncommon for inguinal hernia to be recorded on their death certificates. Of the operations, 91% were undertaken on males; age-specific rates were highest in infants and the elderly; and emergency operation rates rose exponentially with age in people > 50 years., Conclusions: The lifetime 'risk' of inguinal hernia repair is high: at currently prevailing rates we estimate it at 27% for men and 3% for women. There is significant elevation of mortality after emergency operations. Elective repair of inguinal hernia should be undertaken soon after the diagnosis is made to minimize the risk of adverse outcomes.

Background: Crohn's disease and ulcerative colitis are chronic relapsing conditions. National hospital statistics in England only provide episode-based admission rates and cannot be used to identify multiple admissions per person. We used record linkage to provide a person-based profile of admission rates., Methods: Age-standardized admission rates were calculated from the computer tapes of the Hospital In-patient Enquiry (HIPE) for 1970-1985 and the Oxford Record Linkage Study (ORLS) for the period 1970-1986. In addition, annual hospitalized prevalence, first hospital admission rates (as a proxy for incidence) and readmission rates were calculated for the Oxford population. Predictors of relapses were assessed by logistic regression models., Results: Episode-based admission rates for Crohn's disease increased over time, both nationally and in Oxford. In Oxford, hospitalized incidence rates showed no increase for Crohn's disease. Neither episode-based nor person-based rates increased for ulcerative colitis. Relapses resulting in hospital admission were more common for Crohn's disease than for ulcerative colitis. They increased over time. We showed the influence of some sociodemographic characteristics (age, social class, district of residence, operations) on relapses., Conclusions: Data on episodes of hospital care for Crohn's disease showed an increase over time while data related to individuals in receipt of care showed no increase over time. Unlinked episodes of hospital care are of limited value when studying temporal trends for chronic conditions with multiple admissions.

We analysed hospital use for 58 common clinical conditions in the medical specialties, using data from the two districts covered by the Oxford record linkage study 1968-1986. Episode rates, person rates, and ratios of multiple admissions per person were computed. In young adults, poisoning was the most common reason for admission. In older adults, the most common clinical conditions included atherosclerotic diseases and smoking-related lung diseases. Comparing the first and last time periods studied, admission rates increased by 10% or more in 37 of the 58 conditions, including 7 of the 10 conditions with the highest overall hospitalization rates. Conditions in which admissions increased by 10% or more included myocardial infarction, other ischaemic heart disease, chronic obstructive lung disease, asthma, pneumonia, diabetes, poisoning, dementia, prostate cancer and breast cancer among others. Workload declined by 10% or more in 13 conditions, including stroke, subarachnoid haemorrhage, hypertension, thyrotoxicosis, acquired hypothyroidism, and tuberculosis. Secular trends in hospital use are generally attributable either to changes in disease frequency in the population or to changes in clinic- or hospital-based technology and practice.

Admission rates, multiple admissions per individual and time spent in hospital in general medical and geriatric care are described using data from the Oxford Record Linkage Study from 1968-86. For patients aged 15-39 years, age-specific admission rates did not vary appreciably with age and were a little higher in women than in men. For patients aged 40 years and over, admission rates rose steeply with age and were considerably higher in men than in women. Admission rates, measured as episodes, increased over time by 3.4% per year in women and 3.7% in men. Measured as individual people admitted per year, they increased by 2.2% per year people in women and 2.6% in men. Expressed as age-standardized rates, they increased by 1.5% per year in women and 1.8% in men. The greater rise in episodes than in people treated reflected an increase in repeat admissions per patient admitted. Mean length of stay per hospital episode and total time spent in hospital per patient admitted per year both showed a consistent decline over time. Increases in admission rates were seen in all of the common broad clinical groupings studied, except infectious diseases which, as a group, showed a mean annual decrease of just over 2% per year.

Background: Appendicectomy is one of the commonest operations in most developed countries, especially in children and young adults. We used routine abstracts of hospital inpatient records to study the demographic and temporal profiles of emergency appendicectomy for acute appendicitis and appendicectomy in other circumstances., Methods: Records held in the Oxford record linkage study (ORLS) from 1970-1986 inclusive were analysed. Age- and sex-specific admission rates were studied, subdividing appendicectomy into three main categories: emergency appendicectomy for acute appendicitis, emergency appendicectomy as the main operation without appendicitis recorded as a diagnosis, and prophylactic or incidental appendicectomy with other operations but without appendicitis., Results: A total of 47,505 records of appendicectomy were analysed. Emergency appendicectomy for acute appendicitis was more common in males than females, peaked in the 10-19 year age groups, and declined over time. Emergency appendicectomy without appendicitis was more common in women than men (female to male ratio 1.8:1), peaked at age 15-19 years and did not decline over time. Incidental appendicectomy was much commoner in women (female to male ratio 3:1), peaked at older ages than the first two groups, and declined significantly over time., Conclusions: The demographic profiles of patients in these categories were quite different. The data on trends suggest confirmation of a true decline in acute appendicitis, no decline for conditions which may mimic it, and a decline in the use of prophylactic and incidental appendicectomy. The operations in the latter categories--appendicectomy without acute appendicitis--were much commoner in women than men and their appropriateness would be worthwhile topics for medical audit.

Study Objective: To determine the extent to which individual diseases, when recorded as being present shortly before death, were certified as causes of death., Design: Retrospective cohort study in which the "subjects" were computerised linked records., Setting: Six districts in the Oxford Regional Health Authority area (covering a population of 1.9 million people)., Subjects: Linked abstracts of hospital records and death certificates for people who died within four weeks and, for some diseases, within one year of hospital admission., Main Outcome Measures: The percentage of people with each disease for whom the disease was recorded as the underlying cause of death, was recorded elsewhere on the death certificate, or was not certified as a cause of death at all., Results: Three broad patterns of certification are distinguished. Firstly, there were diseases that were usually recorded on death certificates when death occurred within four weeks of hospital care of them. Examples included lung cancer (on 91% of such death certificates), breast cancer (92%), leukaemia and lymphoma (90%), anterior horn cell disease (89%), multiple sclerosis (89%), myocardial infarction (90%), stroke (93%), aortic aneurysm (87%), and spina bifida (89%). These diseases were also usually certified as the underlying cause of death. Secondly, there were diseases which, when present within four weeks of death, were commonly recorded on death certificates but often not as the underlying cause of death. Examples included tuberculosis (on 76% of such certificates; underlying cause on 54%), thyroid disease (49%; 21%), diabetes mellitus (69%; 30%) and hypertension (43%; 22%). Thirdly, there were conditions which, when death occurred within four weeks of their treatment, were recorded on the death certificate in a minority of cases only. Examples of these included fractured neck of femur (on 25% of such certificates), asthma (37%), and anaemia (22%). Not surprisingly, there was "convergence" in certification practice towards the common cardiovascular and respiratory causes of death. There was also evidence that conditions regarded as avoidable causes of death may not have been certified when present at death in some patients., Conclusion: When uses are made of mortality statistics alone, it is important to know which category of certification practice the disease of interest is likely to be in. Linkage between morbidity and mortality records, and multiple cause analysis of mortality, would considerably improve the ability to quantify mortality associated with individual diseases.

Trends in admission rates, patterns of readmission, lengths of stay and clinical caseload for in-patient dermatology from 1976 to 1985 are described using data from the Oxford record-linkage study. Age-specific admission rates were considerably higher in people aged 50 years and over than in younger people. Admission rates declined over time in most age-sex groups below the age of 70 years, but increased over time for the over 70s. In dermatology, unlike most other specialties, the length of patients' stay did not decrease substantially over the 10 years. In-patient workload consisted predominantly of leg ulcers, psoriasis, and eczema. This did not change appreciably over time. New out-patients at dermatology clinics rose by 41% from 1976 to 1985, and all out-patient visits rose by 20% during the 10-year period. Because the profile of in-patient workload changed relatively little over time, we speculate that the impact of innovations in dermatological practice has been much greater in the ambulatory setting than in the management of those patients requiring prolonged in-patient care. Future routine measures of workload in dermatology should include demographic and clinical data on out-patients.

Study Objective: The aim was to report on the extent to which death certificates which specify that death occurred in hospital can be matched and linked with routine hospital inpatient information systems., Design: The study involved linkage of hospital records which specified that death occurred in hospital to corresponding death certificates; and linkage of death certificates which specified that death occurred in hospital to corresponding hospital records., Setting: Six health districts in southern England covered by medical record linkage., Subjects: Records were examined of patients aged 65 years and over, which specified that death occurred in hospital between 1979 and 1985., Main Results: 98.2% of hospital record abstracts which specified that death occurred in hospital were linked by our standard computer-based techniques to death certificates. Conversely, however, only 94.4% of death certificates which specified that death occurred in hospital could be linked to the abstracts of corresponding hospital inpatient records. A major factor contributing to the latter failures may be a difference of definition of what constitutes a death "following hospital admission" in patients who die shortly after arrival at hospital., Conclusions: Linkage of hospital records to death certificates is both feasible and desirable. Error rates are generally small; but hospital inpatient record abstracts corresponding to death certificates for deaths in hospital may not invariably exist when death occurs shortly after the arrival of the patient at hospital.

Data from the Oxford Region were used to study trends in hospital admission rates and demographic profiles of hospital care in the National Health Service in oral and maxillofacial surgery. In a defined population of 1.9 million people, admission rates for inpatient care, day case care, and outpatient attendance rates all almost doubled between 1975-1985. Population-based age-specific admission rates were much higher in teenagers and young adults than in other age-groups. In these age-groups admission rates for females were about double those for males. Whilst perhaps not surprising to the oral and maxillofacial surgeon, these demographic profiles of workload are strikingly different from those found in most other hospital specialties.

Study Objective: The aim was to identify and compare rates of admission to hospital of preschool children for medicinal and non-medicinal poisoning in a defined population., Design: The study was an analysis of computerised abstracts of hospital inpatient records for poisoning., Setting: Six districts in southern England covered by the Oxford record linkage study., Subjects: The subjects were children under six years of age residing in the six districts from 1975 to 1986., Measurements and Main Results: 6152 children, drawn from an average annual resident population of 164,000 children in 1975-1986, experienced 6562 hospital admissions for poisoning before six years; 3702 (56.4%) were attributed to medicinal and 2860 (43.6%) to non-medicinal agents. Of the latter, 646 (9.8% of the total) were recorded under the International classification of diseases code, described as "noxious food" (almost exclusively plant material). Average annual admission rates in children under six were 1.88 per 1000 for medicinal agents and 1.45 for non-medicinal substances. Analgesics accounted for 28.1% of the admissions for medicinal poisoning; berries and mushrooms for 97.4% of the plant materials; and corrosive aromatics, acids and alkalis for 22.0% of the other non-medicinals. Admission rates were higher in males than females in each category of poisoning. In children aged 1-4 years there was a significant decrease in admission rates between 1975 and 1986, averaging per annum 5.8% for medicinal poisoning, 6.9% for non-medicinal poisoning (excluding plant material), and 12.8% for plant material poisoning. Significant seasonal variation was found for each class of poisoning., Conclusions: Admission rates for medicinal and non-medicinal poisoning in preschool children declined between 1975 and 1986. The decline could reflect a change in thresholds for admission although, if so, this would be against the general trend in paediatric medical admissions, which is upward. An alternative explanation is a decline in the incidence of poisoning.

In the Oxford region 8,903 residents with oesophageal or gastric cancers were registered by the Oxford Cancer Registry between 1974 and 1988. For most of this time the Registry's practice was to code all adenocarcinomas of the oesophagus as adenocarcinomas of the cardia of stomach. There was a significant increase over time in the registered incidence of adenocarcinoma of the cardia, no appreciable change in the incidence of oesophageal cancers registered as such, and a decline in registered incidence of cancers of the stomach other than cardia.

It has been widely recommended that children should be admitted to hospital only if treatment cannot be provided at home, and that durations of hospital stay should be minimized. We have used record linkage to calculate a statistic which is not yet commonly available, the total time spent in hospital by children per year, and have compared this between six districts in the Oxford Region. Hospitalization rates for children who stayed a total of two days or less per year in hospital increased over time; rates for children who stayed more than two days declined. Mean and median total days spent in hospital varied between districts but, in absolute terms, the differences were small at less than one day's difference between districts per year per child admitted. Inter-district variation decreased over time, although the variation in use of day case care which remained suggests that some districts could still do more work in this fashion.