-
[show abstract]
[hide abstract]
ABSTRACT: Using data from the Oxford Survey of Childhood Cancers this paper examines the effect of foetal age and number of films used on the subsequent risk of childhood cancer associated with prenatal x-rays. X-rays early in pregnancy were taken for different reasons and required more films when compared with those taken in late pregnancy. Therefore, Mantel-Haenszel techniques were used to estimate the independent effects of (a) exposure age and (b) number of films. Age at exposure had a clearly significant effect; x-rays taken in the first trimester of pregnancy were 2.69 times as effective as x-rays taken in the third trimester. First trimester exposures were often the result of maternal illnesses, so these maternal illnesses were then included among the controlling factors. When this was done the first trimester x-rays were 2.73 times as effective as later exposures. First trimester x-rays were most strongly associated with the cancers which were diagnosed between 4 and 5 years of age. Although the number of films had no detectable effect upon relative risk calculated over all ages, multiple exposures were demonstrably associated with early age at diagnosis.
Journal of Radiological Protection 09/2002; 8(1):3. · 1.39 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Outdoor terrestrial gamma radiation exposure levels (TGR), estimated for each of the 10 km squares of the Great Britain National Grid, were related to local cancer death rates in childhood The examination was based upon the prior hypothesis that an association ought to be detectable This was itself based upon an examination of geographical TGR variations and upon a recently reported recalculation of the dose-response relationship between the risk of childhood cancer and foetal exposure to medical x-rays The analysis was pressed through several stages in which the effects of sociodemographic and medical confounding factors and their temporal changes were identified and separated. TGR was then shown to exert an independent statistically significant effect.
Journal of Radiological Protection 09/2002; 8(1):9. · 1.39 Impact Factor
-
E G Knox
[show abstract]
[hide abstract]
ABSTRACT: The dates and places of 105 suspected or proven murders committed by Dr H. Shipman of Hyde in Greater Manchester between 1984 and 1998 were subjected to epidemiological analysis. These interim data were assembled through a variety of media sources and were based upon court proceedings and police investigations. The analysis revealed a significant excess of case pairs separated jointly by distances <0.6 km and by times <7 days. These sequences were also associated with purely geographical groupings within spatial diameters <0.2 km, but with longer time intervals. This was confirmed by an extended analysis of case triplets occurring within short times and distances. They showed a significant excess. These clusters were probably generated by a combination of psychopathic obsession, of local opportunity, and of caution; and in similar circumstances could occur again. The findings demand the regular display of mortality data in a format permitting the intuitive recognition of similar phenomena elsewhere.
Journal of Public Health Medicine 03/2002; 24(1):34-7.
-
[show abstract]
[hide abstract]
ABSTRACT: To compare long term outcomes of a randomised controlled trial of anti-smoking education in pregnancy and to examine the same outcomes according to maternal pregnancy smoking behaviour.
Follow up of the population included in the randomised controlled trial nine years later and of ex-smokers and non-smokers within the same hospital population.
A maternity hospital in Birmingham with follow up of children in schools and mothers at home.
1218 smokers recruited to the trial; also 191 ex-smokers at booking and 414 non-smokers throughout pregnancy.
Children were assessed individually by psychologists in schools, and mothers interviewed at home to obtain additional information relevant to cognitive development and growth. Information on smoking during pregnancy was obtained from mothers and obstetric data from computerised case-notes, both recorded immediately following delivery.
Height, weight, IQ and neurological soft signs at 9.4 years.
Differences in birthweight and length between the intervention and control groups were confirmed but no intervention-control differences were found at age 9.4 for weight, height, IQ or neurological soft signs. Differences were found for height and IQ according to mothers pregnancy smoking behaviour, but smoking did not remain an independent predictor after taking account of confounding factors. Alternative classifications of smoking behaviour, taking account of the gestation at stopping and mean cigarette consumption throughout pregnancy likewise showed no effect.
The well established early hazards of smoking during pregnancy seem to be resolved by later childhood, with no evidence of direct long term effects on growth or cognitive functioning.
BJOG An International Journal of Obstetrics & Gynaecology 02/2001; 108(1):67-73. · 3.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Estimates of the relative risk of childhood cancer, following irradiation during fetal life, are reported. They are based upon extended case-control investigations of childhood cancer deaths in England, Wales and Scotland between 1953 and 1979 comprising 14759 geographically-matched and birth-date-matched case/control pairs. The estimates were calculated using Conditional Logistic Regression (Miettinen-Breslow) techniques. This method of risk-estimation limits the distortions caused by confounding factors or by biased selection of controls. Through analysing a range of reported exposures other than radiation, levels of general reporting and recording biases between cases and controls were also assessed. There was no evidence among cases or controls of any systematic reduction in the frequency of pregnancy x-rays between 1950 and 1979. During this period of time, about 7 per cent of all childhood cancers, and 8 per cent of those with onset between the ages of 4 and 7 years, were caused by X-ray examinations. The dose-response relationship was one death per 990 obstetric X-ray examinations; or 2000 deaths per 104 man-Gy.
Journal of the Society for Radiological Protection 12/2000; 7(4):177.
-
[show abstract]
[hide abstract]
ABSTRACT: To investigate the early migration patterns of children who later developed cancer. To test a prior hypothesis that some cancers are initiated by early exposures to toxic atmospheric pollutants from point sources.
Address changes in children dying from cancer are examined in relation to potentially hazardous sites of several different types. The relative proximities of birth addresses and death addresses to these sites, are compared. The approach is based upon the premise that a local exposure, effective only at an early age, must be preferentially linked with an early address.
Records of 22,458 children dying from leukaemia or other cancer under the age of 16 years in Great Britain between 1953 and 1980: including 9224 who moved house between birth and death. The migration analysis was based upon birth and death addresses, converted first to postcodes and thence to map coordinates. The geographical locations of potentially toxic industrial sites were obtained through direct map searches and from commercial directories.
Systematic asymmetries were found between measured distances from birth and death addresses to sources emitting volatile organic compounds, or using large scale combustion processes. The children had more often moved away from these hazards than towards them. Many of the sources had already been identified as hazardous using other methods. There was also a birth association with areas of dense habitation; possibly because of unidentified toxic sources contained within them. All forms of cancer were involved although some effluents were associated preferentially with specific types.
The main findings of an earlier study, based upon a different and independent method, were confirmed. Proximities to several types of industrial source, around the time of birth, were followed by a raised risk of childhood cancer. Combustion products and volatile organic compounds were especially implicated. Within the 16 year limit of the study, the increased risk did not decay with advancing age. Low atmospheric concentrations of many carcinogenic substances suggest that the mother acts as a cumulative filter and passes them to the fetus across the placenta or in breast milk.
Journal of Epidemiology & Community Health 12/1998; 52(11):716-26. · 3.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Using birth addresses, we examined the geographical variation in risk for all types of childhood cancers in the UK, on a scale corresponding to the 10-km squares of the National Grid. The effects of socioeconomic and environmental factors, including natural background radiation, were investigated and their relative importance assessed using Poisson regression. Data came from a national collection of all fatal cancers between 1953 and 1980 in children aged 0-15 years and consisted of 9363 children of known place of birth from 12 complete annual cohorts born in the period 1953-64. For solid cancers, as well as for leukaemias and lymphomas, there was marked variation of cumulative mortality according to place of birth. High mortalities were associated with areas characterized as having high social class, higher incomes and good housing conditions, but also with high population densities (births per hectare). Each of these contrasting social indicators operated independently of the other, indicating complex determining mechanisms. Mortalities increased with increased radon exposure, and the relationship operated independently of the socioeconomic factors. At this scale of analysis, we found no increased mortality in industrialized areas. A population-mixing infective hypothesis, which postulates high rates of leukaemia when highly exposed urban populations are introduced to isolated rural areas, was supported by observations of high mortalities in 'growth areas' and New Towns, but was not readily reconcilable with the high rates seen in the high-density areas. If these correlations do indeed represent an infective mechanism, then the outcomes are not limited to malignancies of the immune system alone.
British Journal of Cancer 03/1998; 77(5):842-9. · 5.04 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Firstly, to examine relationships between the birth and death addresses of children dying from leukaemia and cancer in Great Britain, and the sites of potential environmental hazards; and secondly to measure relative case densities close to, and at increasing distances from, different hazard types.
Home address postcodes (PCs) and their map coordinates were identified at birth and at death in children who died from leukaemia or cancer. Potentially hazardous industrial addresses and PCs were listed from business and other directories, and map coordinates obtained from the Central Postcode Directory or else located directly on Ordnance Survey (OS) maps. Railway lines and motorways were digitised from OS maps. Numbers of deaths (and births) at successive radial distances from these hazards were counted and compared with expected numbers. The latter were based on a count of all PCs at similar distances. Relative case density ratios at successive distances from the hazards were obtained from observed and expected numbers, aggregated over similar sites. This was repeated for different hazard types and results were tested for evidence of systematic centrifugal case density gradients.
All 22,458 children dying from leukaemia or cancer aged 0-15 years, in England, Wales, and Scotland, between 1953 and 1980.
Relative excesses of leukaemias and of solid cancers were found near the following: (1) oil refineries, major oil storage installations, railside oil distribution terminals and factories making bitumen products; (2) motor car factories, coach builders, and car body repairers; (3) major users of petroleum products including manufacturers of solvents, paint sprayers, fibreglass fabricators, paint and varnish makers, plastics and detergent manufacturers, and galvanisers; (4) users of kilns and furnaces including steelworks, power stations, galvanisers, cement makers, brickworks, crematoria and aluminium, zinc, and iron/steel foundries; (5) airfields, railways, motorways and harbours. The findings for leukaemias and for solid cancers were indistinguishable. The hazard proximities of birth addresses were stronger than for death addresses. For children who had moved house between birth and death, the proximity effect was limited to the birth addresses.
Childhood cancers are geographically associated with two main types of industrial atmospheric effluent namely: (1) petroleum derived volatiles and (2) kiln and furnace smoke and gases, and effluents from internal combustion engines.
Journal of Epidemiology & Community Health 05/1997; 51(2):151-9. · 3.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Firstly, to identify spatially close pairs and triplets of childhood leukaemias and cancers in Britain. Secondly, to compare pair frequencies with random expectations, identify excesses, and measure the diameters of any clusters. Thirdly, to infer possible causes.
Stratified Poisson analyses of two comprehensive sets of childhood leukaemia and cancer data in Great Britain: seeking home address pairs within particular census enumeration districts (EDs) or postcodes (PCs). Numbers of pairs/triplets of leukaemia registrations sharing single or adjacent EDs were compared with Poisson, expectations in national ED strata with different numbers of households (HHs). Pairs/triplets of leukaemia/cancer deaths (and births) sharing a single PC were compared with Poisson expectations in national PC strata with different numbers of postal delivery points (DPs). Same and adjacent house pairs were identified individually among the same PC death pairs. Areal case densities were estimated around a sample of index cases, using their own PC grid coordinates, and those recorded in the central PC directory.
These comprised, firstly, all cases of childhood leukaemia and non-Hodgkin lymphoma registered between 1966 and 1983 in England and Wales (ED analysis) and, secondly, all childhood leukaemia and cancer deaths between 1953 and 1980, in England, Wales, and Scotland (PC analyses at birth and at death).
Short range spatial clustering was demonstrated (a) for leukaemia at place of registration, and (b) for leukaemia and cancer (separately and jointly) at both birth and death addresses. There was evidence of additional case pairing in adjacent PCs. Both data sets showed a relative local pair excess of about 1.5, within diameters of 300 metres. Secondary case densities, measured within 600 metres of a sample of unpaired index cases, were raised by the same ratio. The raised risk then tapered with increasing distance to about 3 km. Forty-four non-twin pairs had died at exactly the same address, far in excess of random expectation. This same house excess was due entirely to 31 sibling pairs. They also showed a relative excess of central nervous system and other solid tumours; but without the exact tumour type sibling concordances sometimes seen in MZ twins. The sibling pairs were only a small part of the overall excess of same PC pairs.
Short range geographical clustering probably reflects two separate causes of childhood cancer, namely (a) an uncommon familial susceptibility to solid cancers, probably inherited, and (b) a group of long standing focal environmental hazards, most effective within a few hundred metres of the source, but detectable as far as 3 km.
Journal of Epidemiology & Community Health 07/1996; 50(3):313-9. · 3.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To examine a national data set of all childhood cancers for evidence of space-time interactions within three distinct sets of dates and places (at birth, at diagnosis, and at death), to show whether the patterns found for these events represent separate phenomena or statistically interdependent processes, and to see whether the childhood leukaemias and the childhood solid cancers have separate distinctive patterns in these respects.
This was a space-time cluster analysis. The large number of cases enabled division of the data into two sets, one for hypothesis generation and the other for hypothesis testing.
England, Scotland, and Wales.
A national collection of 22,360 children aged 0-15 years with fatal cancers and leukaemias in the period 1953 to 1980.
There was significant clustering among the leukaemias and lymphomas on date and place of birth (particularly among cases born within 1 km and up to 5 months apart), and on date and place of diagnosis (particularly among cases diagnosed from 3 to 5 km apart and up to 9 months apart). There was no clustering among the solid cancers. These findings were confirmed in two separate analyses of two separate sets of data.
The birth clustering was significant among pairs diagnosed at differing ages, and diagnosis clustering was significant among pairs born at different times, and it was concluded that the two types of clustering must be regarded as separate and statistically independent phenomena. Both the birth and the diagnosis clusters comprised many independent pairs of cases, with no large multiple case clusters. This suggests the involvement of multiple time-space localised exposures to hazards with short and constant latent intervals; probably an infectious agent or an environmental toxin. Given the separate nature of the two types of clustering, exposure to more than one hazard may be involved.
Journal of Epidemiology & Community Health 05/1995; 49(2):158-63. · 3.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: While obstetric problems in Asian women have been documented, little is known about longer term health problems following childbirth. This study compares long-term postpartum morbidity in Asian and Caucasian women who had had an infant at a Birmingham maternity unit between 1978 and 1985. A total of 11,701 women returned the questionnaire asking about their experience of a list of 25 health problems. It was found that backache, frequent headaches, shoulderache and pains and weakness in the arms and legs all occurred more commonly among the 530 Asian women than in Caucasian women, even after standardizing for confounding factors. All these symptoms started within three months of the birth, lasted more than six weeks and had not previously been experienced. Most symptoms persisted for more than a year, and even after several years, many had not resolved. The possible role of vitamin D deficiency and the value of antenatal vitamin D supplements are discussed.
British Journal of General Practice 01/1994; 43(377):519-22. · 1.83 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To examine the association between accidental dural puncture and long term headache and related symptoms.
Postal questionnaire survey to elucidate new symptoms occurring after childbirth, and linking of these to data in obstetric and anaesthetic case notes. Women were surveyed between 13 months and nine years after delivery.
Birmingham Maternity Hospital.
4700 women who had delivered their most recent baby under epidural anaesthesia, 74 of whom had suffered an accidental dural puncture.
Frequencies of new headache or migraine or neck ache starting within three months after childbirth and lasting over six weeks.
Among the 74 women who had had an accidental dural puncture there were 17 (23%) who reported one or more of the above symptoms. By comparison, among those who had had an epidural anaesthetic but no recorded puncture, only 329 (7.1%) reported these symptoms. The duration of the headache or migraine or neck ache in the dural tap group ranged from nine weeks to over eight years. Ten of these women reported still unresolved symptoms.
Conclusions on causality were tentative. Most women would remember a dural tap, and this might influence their reporting of subsequent symptoms attributable to the event. In addition, detailed characterisation of the symptoms was not available. Nevertheless, the findings provide a clear indication of the need for further study of the possible long term sequelae of accidental dural puncture.
BMJ 05/1993; 306(6882):883-5. · 14.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Opinions about pain relief were sought from a sample of 11,701 women 13 months to 9 years after giving birth. Their opinions related both to levels of satisfaction with the particular forms of pain relief used and to the presence of any feelings of deprivation of the birth process. Of all forms of pain relief examined epidural anaesthesia was associated with the highest levels of satisfaction. In vaginal deliveries, 69.4% of those who had an epidural were fully satisfied, compared with 29.5% for inhalation analgesia, 20.7% for pethidine and 29.4% for relaxation techniques. Women who had spontaneous deliveries and shorter labours were least satisfied with their epidurals, while the reverse was generally true for the other forms of pain relief. After an epidural for vaginal delivery 7.1% of women reported feelings of deprivation of the full pleasure of childbirth. This was higher than the 1.4% previously reported by women in the same maternity unit when questioned immediately after the delivery,(1) but still only represents a minority of women. After an emergency caesarean section administered under epidural feelings of deprivation were expressed by 5.1%, but by only 1.7% after an elective section under epidural. Among women using pethidine 3.5% felt that this had deprived them of the pleasure of giving birth.
International Journal of Obstetric Anesthesia 02/1993; 2(1):3-11. · 1.39 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The aim was to test a large set of childhood leukaemia and lymphoma registrations for the presence of clusters in space and in time.
The study was a space-time cluster analysis.
England, Wales and Scotland.
All registrations for leukaemia and lymphoma between 1966 and 1983 in children aged 0 to 14 years were examined. The records included date and age of registration, sex, diagnosis, and the map reference of the postcode of residence. Of the 9411 registrations, 8888 were suitable for inclusion.
There was a statistically significant excess of case pairs occurring jointly within 0.5 km and 60 d of each other: 68 pairs compared with 50.0 expected. The excess was detectable in central England, in the north of England and Scotland, but not in the south west of England. It was concentrated within the age band 4 to 7 years and among the lymphatic leukaemias. Several potential artefacts were considered and excluded, but the possibility remained that clustered detections might be triggered by haematological examinations undertaken for some communicable disease.
There was strong evidence of joint spatial-temporal clustering, with an excess of pairs separated by very short time and distance intervals. The causes are probably biological rather than artefactual, but further work will be necessary in order to exclude the latter.
Journal of Epidemiology & Community Health 01/1993; 46(6):566-72. · 3.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The aim was to test a large set of childhood leukaemia and lymphoma registrations for the presence of short radius spacial clusters.
The study was a geographical cluster analysis.
England, Wales and Scotland.
All registrations for leukaemia and lymphoma between 1966 and 1983 in children aged 0 to 14 years were examined. The records included date and age of registration, sex, diagnosis, and the map reference of the postcode of residence. Of the 9411 registrations, 8888 were suitable for inclusion.
There was a significant excess of case pair addresses separated by < 0.5 km. There was also a significant excess of pairs sharing the same postcode. Both findings were based upon comparison with random pairs of postcodes drawn from the Central Postcode Directory. Examination for clustering at this very short range was based upon a clear prior hypothesis derived from the results of a study of space-time interaction, reported in a companion paper.
It is postulated that the space-time interaction and the geographical concentrations shown here result from a common epidemic process. The epidemiology of this disease is characterised by short range geographical concentrations, with temporal non-homogeneity superimposed. The findings exclude certain artefacts which remained unresolved in the space-time interaction study. The distributions almost certainly reflect biological processes, and the most probable explanation is in terms of an infective process.
Journal of Epidemiology & Community Health 12/1992; 46(6):573-6. · 3.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To examine the association between obstetric epidural anaesthesia and subsequent long term problems.
Postal questionnaire on health problems after childbirth linked to maternity case note data.
Maternity hospital in Birmingham.
11701 women who delivered their most recent child during 1978-85 and who returned completed questionnaires.
Frequencies of long term symptoms after childbirth.
Compared with the 6935 women who did not have epidural anaesthesia the 4766 women who did more commonly experienced backache (903 (18.9%) with epidural v 731 (10.5%) without epidural), frequent headaches 220 (4.6%) v 199 (2.9%)), migraine (92 (1.9%) v 73 (1.1%)), neckache (116 (2.4%) v 112 (1.6%)), and tingling in hands or fingers (143 (3.0%) v 150 (2.2%)). The results could not be explained by correlated social or obstetric factors. The associations with head, neck, and hand symptoms were found only in women who reported backache. An excess of visual disturbances among women who had epidural anaesthesia (83 (1.7%) v 91 (1.3%)) was present only in association with migraine, but excess of dizziness or fainting (102 (2.1%) v 109 (1.6%)) was independent of other symptoms. 26 women had numbness or tingling in the lower back, buttocks, and leg, of whom 23 had had epidural anaesthesia. Of 34 women with spinal headache, nine (five after accidental dural puncture; four after spinal block) reported long term headaches.
These associations may indicate a causal sequence, although this cannot be proved from this type of study. Randomised trials of epidural anaesthesia are required to determine whether causal relations exist.
BMJ 06/1992; 304(6837):1279-82. · 14.09 Impact Factor
-
British Journal of Obstetrics and Gynaecology 01/1992; 98(12):1193-5.
-
[show abstract]
[hide abstract]
ABSTRACT: The spatial and temporal distributions of cot deaths and of infant respiratory deaths in Birmingham between 1964 and 1984 were examined. Respiratory deaths declined and cot deaths increased, and the combined rate showed a downward trend. Seasonal variations were identical in the two groups and in each case were more powerfully related to date of death than to date of birth. Cumulative mortalities were parallel by age, depended crucially upon the quarter of the year in which the child was born, and were identical for the two classes of death. The separation of the temporal trends probably owed more to changes in diagnostic practice than to biological or epidemiological processes. Powerful space-time interactions were detected for both groups and for cross-pairs belonging to different groups. There was a four-yearly oscillation in the combined death rate, of doubtful statistical significance, but synchronous with a similar oscillation reported by other investigators using national data. The four-yearly oscillation was also synchronous with the four-yearly pattern for national isolations of Mycoplasma pneumoniae.
Journal of Public Health Medicine 09/1991; 13(3):142-50.
-
[show abstract]
[hide abstract]
ABSTRACT: To examine the relation between epidural anaesthesia and long term backache after childbirth.
Data from postal questionnaire on morbidity after childbirth sent to women who had delivered in one maternity hospital between 1978 and 1985 were linked to maternity case notes for each woman.
Maternity hospital in Birmingham.
11,701 Women who had delivered their most recent baby at the maternity hospital during the defined period and who returned their completed questionnaires.
Of the 1634 women who reported backache, 1132 (69%) had had it for over a year. A significant association was found between backache and epidural anaesthesia (relative risk = 1.8); 903 of 4766 women (18.9%) who had had epidural anaesthesia reported this symptom, compared with 731 of the 6935 women (10.5%) who had not had epidural anaesthesia. This association was consistent in both "normal" and "abnormal" deliveries, the only exception being after an elective caesarean section when no excess backache occurred after epidural anaesthesia.
The relation between backache and epidural anaesthesia is probably causal. It seems to result from a combination of effective analgesia and stressed posture during labour. Further investigations on the mechanisms causing backache after epidural anaesthesia are required.
BMJ 08/1990; 301(6742):9-12. · 14.09 Impact Factor
-
E G Knox
[show abstract]
[hide abstract]
ABSTRACT: The Forrest working group on breast cancer screening recommended routine mammography for women in the United Kingdom at ages 50, 53, 56, 59, 62, and 65. Benefits were costed at about 3000 pounds for each life year recovered, but there was no estimate of the cost of each life saved, and the consequent reduction in mortality from breast cancer in the general population of the United Kingdom was not estimated. The present study addressed both of these issues using an interactive computer modelling process. Long term savings were calculated at 900 deaths a year in England and Wales--that is, about 8% of the total deaths from breast cancer--and 9% of life years currently lost. The cost of each death saved from breast cancer was estimated at 39,000 pounds.
BMJ 10/1988; 297(6649):650-4. · 14.09 Impact Factor
