Subsequent cancers within 5 years from initial diagnosis of childhood cancer. Patterns and risks in the population of Great Britain

BACKGROUND

Patterns and risks of subsequent primary tumours (SPTs) among long-term survivors of childhood cancer have been extensively described, but much less is known about early SPTs (ESPTs) occurring within 5 years after initial diagnosis.

PROCEDURE

We carried out a population-based study of ESPTs following childhood cancer throughout Britain, using the National Registry of Childhood Tumours. The full study series comprised all ESPTs occurring among 56,620 children whose initial cancer diagnosis was in the period 1971-2010. Frequencies of ESPT were calculated for the entire cohort. For analyses of risk, follow-up began 92 days after initial diagnosis.

RESULTS

ESPT developed in 0.4% of children overall, 0.52% of those initially diagnosed at age less than 1 year and 0.38% of those diagnosed at age 1-14 years. Standardised incidence ratio (SIR) was 7.7 (95% confidence interval [CI]: 6.7-8.9), overall 9.5 (95% CI: 7.1-12.5) for children initially diagnosed in 1981-1990 and 6.5-7.5 for those from earlier and later decades. SIR by type of first cancer ranged from 4.4 (95% CI: 1.8-9.1) for Wilms tumour to 13.1 (95% CI: 7.7-21.0) for non-Hodgkin lymphoma. SIR by type of ESPT ranged from 2.0 (95% CI: 1.0-3.4) for acute lymphoblastic leukaemia to 66.6 (95% CI: 52.3-83.6) for acute myeloid leukaemia. Predisposition syndromes were known to be implicated in 21% of children with ESPT and suspected in another 5%.

CONCLUSIONS

This study provides an overview of the patterns and risks of ESPTs in a large population where many children received therapy that is still in widespread use. Further research will be needed to monitor and understand changes in risk as childhood cancer treatment continues to evolve.

Case-control study of paternal occupational exposures and childhood bone tumours and soft-tissue sarcomas in Great Britain, 1962-2010

BACKGROUND

This nationwide study investigated associations between paternal occupational exposure and childhood bone tumours and soft- tissue sarcomas.

METHODS

The UK National Registry of Childhood Tumours provided cases of childhood sarcomas born and diagnosed in Great Britain, 1962-2010. Control births, unaffected by childhood cancer, were matched on sex, birth period and birth registration sub-district. Fathers' occupations were assigned to one or more of 33 exposure groups and coded for occupational social class.

RESULTS

We analysed 5,369 childhood sarcoma cases and 5380 controls. Total bone tumours, total soft-tissue sarcomas and the subgroups osteosarcoma, rhabdomyosarcoma and Ewing Sarcoma Family of Tumours (ESFT) were considered separately. Significant positive associations were seen between rhabdomyosarcoma and paternal exposure to EMFs (odds ratio = 1.67, CI = 1.22-2.28) and also for ESFT and textile dust (1.93, 1.01-3.63). There were putative protective effects on total bone tumours of paternal dermal exposure to hydrocarbons, metal, metal working or oil mists.

CONCLUSIONS

Despite the large size and freedom from bias of this study, our results should be interpreted with caution. Many significance tests were undertaken, and chance findings are to be expected. Nevertheless, our finding of associations between ESFT and paternal exposure to textile dust may support related suggestions in the literature.

One-year outcomes of infants born with congenital diaphragmatic hernia: a national population cohort study

OBJECTIVE

To report outcomes to 1 year, in infants born with congenital diaphragmatic hernia (CDH), explore factors associated with infant mortality and examine the relationship between surgical techniques and postoperative morbidity.

DESIGN

Prospective national population cohort study.

SETTING

Paediatric surgical centres in the UK and Ireland.

METHOD

Data were collected to 1 year for infants with CDH live-born between 1 April 2009 to 30 September 2010. Factors associated with infant mortality are explored using logistic regression. Postoperative morbidity following patch versus primary closure, minimally invasive versus open surgery and biological versus synthetic patch material is described. Data are presented as n (%) and median (IQR).

RESULTS

Overall known survival to 1 year was 75%, 95% CI 68% to 81% (138/184) and postoperative survival 93%, 95% CI 88% to 97% (138/148). Female sex, antenatal diagnosis, use of vasodilators or inotropes, being small for gestational age, patch repair and use of surfactant were all associated with infant death. Infants undergoing patch repair had a high incidence of postoperative chylothorax (11/54 vs 2/96 in infants undergoing primary closure) and a long length of hospital stay (41 days, IQR 24-68 vs 16 days, IQR 10-25 in primary closure group). Infants managed with synthetic patch material had a high incidence of chylothorax (11/34 vs 0/19 with biological patch).

CONCLUSION

The majority of infant deaths in babies born with CDH occur before surgical correction. Female sex, being born small for gestational age, surfactant use, patch repair and receipt of cardiovascular support were associated with a higher risk of death. The optimum surgical approach, timing of operation and choice of patch material to achieve lowest morbidity warrants further evaluation.

Case-control study of paternal occupational exposures and childhood lymphoma in Great Britain, 1962-2010

BACKGROUND

This nationwide study investigates associations between paternal occupational exposure and childhood lymphoma.

METHODS

The UK National Registry of Childhood Tumours provided cases of childhood lymphoma born and diagnosed in Great Britain 1962-2010. Control births, unaffected by childhood cancer, were matched on sex, birth period and birth registration sub-district. Fathers' occupations were assigned to one or more of 33 exposure groups and also coded for occupational social class.

RESULTS

We analysed 5033 childhood lymphoma cases and 4990 controls. Total lymphoma and the subgroups Hodgkin, Burkitt and non-Hodgkin lymphoma were considered separately. No one exposure was significantly associated with increased risk within all subgroups and for total lymphoma. However, exposure to "ceramics and glass" was significantly associated with increased risk of total lymphoma, Hodgkin and non-Hodgkin lymphoma. Paternal lead exposure was associated with Burkitt lymphoma and exposure to metal fumes was associated with Hodgkin lymphoma.

CONCLUSIONS

This study provides no support for previous suggestions of an association between childhood lymphoma and paternal occupational exposure to pesticides, solvents/hydrocarbons or infections potentially transmitted by father's social contacts. An association with exposure to "ceramics and glass" was noted for the two major lymphoma subtypes together comprising 80% of total lymphoma.

Cancer risk in children born after donor ART

STUDY QUESTION

Do children born after donor ART have an increased risk of developing childhood cancer in comparison to the general population?

SUMMARY ANSWER

This study showed no overall increased risk of childhood cancer in individuals born after donor ART.

WHAT IS KNOWN ALREADY

Most large population-based studies have shown no increase in overall childhood cancer incidence after non-donor ART; however, other studies have suggested small increased risks in specific cancer types, including haematological cancers. Cancer risk specifically in children born after donor ART has not been investigated to date.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study utilized record linkage to determine the outcome status of all children born in Great Britain (1992-2008) after donor ART. The cohort included 12 137 members who contributed 95 389 person-years of follow-up (average follow-up 7.86 years).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Records of all children born in Great Britain (England, Wales, Scotland) after all forms of donor ART (1992-2008) were linked to the UK National Registry of Childhood Tumours (NRCT) to determine the number who subsequently developed cancer by 15 years of age, by the end of 2008. Rates of overall and type specific cancer (selected a priori) were compared with age, sex and calendar year standardized population-based rates, stratifying for potential mediating/moderating factors including sex, age at diagnosis, birth weight, multiple births, maternal previous live births, assisted conception type and fresh/ cryopreserved cycles.

MAIN RESULTS AND THE ROLE OF CHANCE

In our cohort of 12 137 children born after donor ART (52% male, 55% singleton births), no overall increased risk of cancer was identified. There were 12 cancers detected compared to 14.4 expected (standardized incidence ratio (SIR) 0.83; 95% CI 0.43-1.45; P = 0.50). A small, significant increased risk of hepatoblastoma was found, but the numbers and absolute risks were small (<5 cases observed; SIR 10.28; 95% CI 1.25-37.14; P < 0.05). This increased hepatoblastoma risk was associated with low birthweight.

LIMITATIONS REASONS FOR CAUTION

Although this study includes a large number of children born after donor ART, the rarity of specific diagnostic subgroups of childhood cancer results in few cases and therefore wide CIs for such outcomes. As this is an observational study, it is not possible to adjust for all potential confounders; we have instead used stratification to explore potential moderating and mediating factors, where data were available.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study to investigate cancer risk in children born after donor ART. Although based on small numbers, results are reassuring for families and clinicians. The small but significant increased risk of hepatoblastoma detected was associated with low birthweight, a known risk factor for this tumour type. It should be emphasized that the absolute risks are very small. However, on-going investigation with a longer follow-up is needed.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by Cancer Research UK (C36038/A12535) and the National Institute for Health Research (405526) and supported by the National Institute for Health Research Biomedical Research Centre at Great Ormond Street Hospital for Children NHS Foundation Trust and University College London. The work of the Childhood Cancer Research Group (CCRG) was supported by the charity CHILDREN with CANCER UK, the National Cancer Intelligence Network, the Scottish Government and the Department of Health for England and Wales. There are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Early population-based outcomes of infants born with congenital diaphragmatic hernia

PURPOSE

This study aims to describe short-term outcomes of live-born infants with congenital diaphragmatic hernia (CDH) and to identify prognostic factors associated with early mortality.

DESIGN

A prospective population cohort study was undertaken between April 2009 and September 2010, collecting data on live-born infants with CDH from all 28 paediatric surgical centres in the UK and Ireland using an established surgical surveillance system. Management and outcomes are described. Prognostic factors associated with death before surgery are explored.

RESULTS

Two hundred and nineteen live-born infants with CDH were reported within the data collection period. There were 1.5 times more boys than girls (n=133, 61%). Thirty-five infants (16%) died without an operation. This adverse outcome was associated with female sex (adjusted OR (aOR) 3.96, 95% CI 1.66 to 9.47), prenatal diagnosis (aOR 4.99, 95% CI 1.31 to 18.98), and the need for physiological support in the form of inotropes (aOR 9.96, 95% CI 1.19 to 83.25) or pulmonary vasodilators (aOR 4.09, 95% CI 1.53 to 10.93). Significant variation in practice existed among centres, and some therapies potentially detrimental to infant outcomes were used, including pulmonary surfactant in 45 antenatally diagnosed infants (34%). Utilisation of extracorporeal membrane oxygenation was very low compared with published international studies (n=9/219, 4%). Postoperative 30-day survival was 98% for 182 infants with CDH who were adequately physiologically stabilised and underwent surgery.

CONCLUSION

This is the first British Isles population-based study reporting outcome metrics for infants born with CDH. 16% of babies did not survive to undergo surgery. Factors associated with poor outcome included female sex and prenatal diagnosis. Early postoperative survival in those who underwent surgical repair was excellent.

Childhood cancer research in oxford III: The work of CCRG on ionising radiation

BACKGROUND

High doses of ionising radiation are a known cause of childhood cancer and great public and professional interest attaches to possible links between childhood cancer and lower doses, particularly of man-made radiation. This paper describes work done by the Childhood Cancer Research Group (CCRG) on this topic METHODS: Most UK investigations have made use of the National Registry of Childhood Tumours and associated controls. Epidemiological investigations have included national incidence and mortality analyses, geographical investigations, record linkage and case-control studies. Dosimetric studies use biokinetic and dosimetric modelling.

RESULTS

This paper reviews the work of the CCRG on the association between exposure to ionising radiation and childhood cancer, 1975-2014.

CONCLUSION

The work of CCRG has been influential in developing understanding of the causes of 'clusters' of childhood cancer and the risks arising from exposure to ionising radiation both natural and man-made. Some clusters around nuclear installations have certainly been observed, but ionising radiation does not seem to be a plausible cause. The group's work has also been instrumental in discounting the hypothesis that paternal preconception irradiation was a cause of childhood cancers and has demonstrated an increased leukaemia risk for children exposed to higher levels of natural gamma-ray radiation.

Reanalysis of risks of childhood leukaemia with distance from overhead power lines in the UK

Our previous study of childhood leukaemia and distance to high-voltage overhead power lines in the UK has been included in an international pooled analysis. That pooled analysis used different distance categories to those we did, which has focussed attention on the effect of that choice. We re-analyse our previous subjects, using finer distance categories. In the 1960s and 1970s, when we principally found an elevated risk, the risk did not fall monotonically with distance from the power line but had a maximum at 100-200 m. This weakens the evidence that any elevated risks are related to magnetic fields, and slightly strengthens the evidence for a possible effect involving residential mobility or other socioeconomic factors.

Childhood cancer research in Oxford II: The Childhood Cancer Research Group

BACKGROUND

We summarise the work of the Childhood Cancer Research Group, particularly in relation to the UK National Registry of Childhood Tumours (NRCT).

METHODS

The Group was responsible for setting up and maintaining the NRCT. This registry was based on notifications from regional cancer registries, specialist children's tumour registries, paediatric oncologists and clinical trials organisers. For a large sample of cases, data on controls matched by date and place of birth were also collected.

RESULTS

Significant achievements of the Group include: studies of aetiology and of genetic epidemiology; proposals for, and participation in, international comparative studies of these diseases and on a classification system specifically for childhood cancer; the initial development of, and major contributions to, follow-up studies of the health of long-term survivors; the enhancement of cancer registration records by the addition of clinical data and of birth records. The Group made substantial contributions to the UK government's Committee on Medical Aspects of Radiation in the Environment.

CONCLUSION

An important part of the ethos of the Group was to work in collaboration with many other organisations and individuals, both nationally and internationally: many of the Group's achievements described here were the result of such collaborations.

Risks of ovarian, breast, and corpus uteri cancer in women treated with assisted reproductive technology in Great Britain, 1991-2010: data linkage study including 2.2 million person years of observation

OBJECTIVE

To investigate the risks of ovarian, breast, and corpus uteri cancer in women who have had assisted reproduction.

DESIGN

Large, population based, data linkage cohort study.

SETTING AND PARTICIPANTS

All women who had assisted reproduction in Great Britain, 1991-2010, as recorded by the Human Fertilisation and Embryology Authority (HFEA).

INTERVENTIONS

HFEA fertility records for cohort members were linked to national cancer registrations.

MAIN OUTCOME MEASURES

Observed first diagnosis of ovarian, breast, and corpus uteri cancer in cohort members were compared with age, sex, and period specific expectation. Standardised incidence ratios (SIRs) were calculated by use of age, sex, and period specific national incidence rates.

RESULTS

255 786 women contributed 2 257 789 person years' follow-up. No significant increased risk of corpus uteri cancer (164 cancers observed v 146.9 cancers expected; SIR 1.12, 95% confidence interval 0.95 to 1.30) was found during an average of 8.8 years' follow-up. This study found no significantly increased risks of breast cancer overall (2578 v 2641.2; SIR 0.98, 0.94 to 1.01) or invasive breast cancer (2272 v 2371.4; SIR 0.96, 0.92 to 1.00). An increased risk of in situ breast cancer (291 v 253.5; SIR 1.15, 1.02 to 1.29; absolute excess risk (AER) 1.7 cases per 100 000 person years, 95% confidence interval 0.2 to 3.2) was detected, associated with an increasing number of treatment cycles (P=0.03). There was an increased risk of ovarian cancer (405 v 291.82; SIR 1.39, 1.26 to 1.53; AER 5.0 cases per 100 000 person years, 3.3 to 6.9), both invasive (264 v 188.1; SIR 1.40, 1.24 to 1.58; AER 3.4 cases per 100 000 person years, 2.0 to 4.9) and borderline (141 v 103.7; SIR 1.36, 1.15 to 1.60; AER 1.7 cases per 100 000 person years, 0.7 to 2.8). Increased risks of ovarian tumours were limited to women with endometriosis, low parity, or both. This study found no increased risk of any ovarian tumour in women treated because of only male factor or unexplained infertility.

CONCLUSIONS

No increased risk of corpus uteri or invasive breast cancer was detected in women who had had assisted reproduction, but increased risks of in situ breast cancer and invasive and borderline ovarian tumours were found in this study. Our results suggest that ovarian tumour risks could be due to patient characteristics, rather than assisted reproduction itself, although both surveillance bias and the effect of treatment are also possibilities. Ongoing monitoring of this population is essential.

The incidence, characteristics, management and outcomes of anaphylaxis in pregnancy: a population-based descriptive study

OBJECTIVE

The aim of this study was to estimate the incidence of anaphylaxis in pregnancy and describe the management and outcomes in the UK.

DESIGN

A population-based descriptive study using the UK Obstetric Surveillance System (UKOSS).

SETTING

All consultant-led maternity units in the UK.

POPULATION

All pregnant women who had anaphylaxis between 1 October 2012 and 30 September 2015. Anaphylaxis was defined as a severe, life-threatening generalised or systemic hypersensitivity reaction.

METHODS

Prospective case notification using UKOSS.

MAIN OUTCOME MEASURES

Maternal mortality, severe maternal morbidity, neonatal mortality and severe neonatal morbidity.

RESULTS

There were 37 confirmed cases of anaphylaxis in pregnancy, giving an estimated incidence of 1.6 (95% CI: 1.1-2.2) per 100 000 maternities. Four cases of anaphylaxis were in women with known penicillin allergies: two received co-amoxiclav and two cephalosporins. Twelve women had anaphylaxis following prophylactic use of antibiotics at the time of a caesarean delivery. Prophylactic use of antibiotics for Group B streptococcal infection accounted for anaphylaxis in one woman. Two women died (5%), 14 (38%) women were admitted to intensive care and seven women (19%) had one or more additional severe maternal morbidities, which included three haemorrhagic events, two cardiac arrests, one thrombotic event and one pneumonia. No infants died; however, in those infants whose mother had anaphylaxis before delivery (n = 18) there were seven (41%) neonatal intensive care unit admissions, three preterm births and one baby was cooled for neonatal encephalopathy.

CONCLUSIONS

Anaphylaxis is a rare severe complication of pregnancy and frequently the result of a reaction to antibiotic administration. This study highlights the seriousness of the outcomes of this condition for the mother. The low incidence is reassuring given the large proportion of the pregnant population that receive prophylactic antibiotics during delivery.

TWEETABLE ABSTRACT

Anaphylaxis is a rare severe complication of pregnancy and frequently the result of a reaction to antibiotic administration.

Developing a set of consensus indicators to support maternity service quality improvement: using Core Outcome Set methodology including a Delphi process

OBJECTIVE

To develop a core metric set to monitor the quality of maternity care.

DESIGN

Delphi process followed by a face-to-face consensus meeting.

SETTING

English maternity units.

POPULATION

Three representative expert panels: service designers, providers and users.

MAIN OUTCOME MEASURES

Maternity care metrics judged important by participants.

METHODS

Participants were asked to complete a two-phase Delphi process, scoring metrics from existing local maternity dashboards. A consensus meeting discussed the results and re-scored the metrics.

RESULTS

In all, 125 distinct metrics across six domains were identified from existing dashboards. Following the consensus meeting, 14 metrics met the inclusion criteria for the final core set: smoking rate at booking; rate of birth without intervention; caesarean section delivery rate in Robson group 1 women; caesarean section delivery rate in Robson group 2 women; caesarean section delivery rate in Robson group 5 women; third- and fourth-degree tear rate among women delivering vaginally; rate of postpartum haemorrhage of ≥1500 ml; rate of successful vaginal birth after a single previous caesarean section; smoking rate at delivery; proportion of babies born at term with an Apgar score <7 at 5 minutes; proportion of babies born at term admitted to the neonatal intensive care unit; proportion of babies readmitted to hospital at <30 days of age; breastfeeding initiation rate; and breastfeeding rate at 6-8 weeks.

CONCLUSIONS

Core outcome set methodology can be used to incorporate the views of key stakeholders in developing a core metric set to monitor the quality of care in maternity units, thus enabling improvement.

TWEETABLE ABSTRACT

Achieving consensus on core metrics for monitoring the quality of maternity care.

Proximity to overhead power lines and childhood leukaemia: an international pooled analysis

BACKGROUND

Although studies have consistently found an association between childhood leukaemia risk and magnetic fields, the associations between childhood leukaemia and distance to overhead power lines have been inconsistent. We pooled data from multiple studies to assess the association with distance and evaluate whether it is due to magnetic fields or other factors associated with distance from lines.

METHODS

We present a pooled analysis combining individual-level data (29,049 cases and 68,231 controls) from 11 record-based studies.

RESULTS

There was no material association between childhood leukaemia and distance to nearest overhead power line of any voltage. Among children living < 50 m from 200 + kV power lines, the adjusted odds ratio for childhood leukaemia was 1.33 (95% CI: 0.92-1.93). The odds ratio was higher among children diagnosed before age 5 years. There was no association with calculated magnetic fields. Odds ratios remained unchanged with adjustment for potential confounders.

CONCLUSIONS

In this first comprehensive pooled analysis of childhood leukaemia and distance to power lines, we found a small and imprecise risk for residences < 50 m of 200 + kV lines that was not explained by high magnetic fields. Reasons for the increased risk, found in this and many other studies, remains to be elucidated.

Variation with socioeconomic status of indoor radon levels in Great Britain: The less affluent have less radon

We demonstrate a strong correlation between domestic radon levels and socio-economic status (SES) in Great Britain, so that radon levels in homes of people with lower SES are, on average, only about two thirds of those of the more affluent. This trend is apparent using small area measures of SES and also using individual social classes. The reasons for these differences are not known with certainty, but may be connected with greater underpressure in warmer and better-sealed dwellings. There is also a variation of indoor radon levels with the design of the house (detached, terraced, etc.). In part this is probably an effect of SES, but it appears to have other causes as well. Data from other countries are also reviewed, and broadly similar effects seen in the United States for SES, and in other European countries for detached vs other types of housing. Because of correlations with smoking, this tendency for the lower SES groups to experience lower radon levels may underlie the negative association between radon levels and lung cancer rates in a well-known ecological study based on US Counties. Those conducting epidemiological studies of radon should be alert for this effect and control adequately for SES.

Epidemiological study of power lines and childhood cancer in the UK: further analyses

We report further analyses from an epidemiological study of childhood cancer and residence at birth near high-voltage power lines in the UK. These results suggest that the elevated risks for childhood leukaemia that we previously found for overhead power lines may be higher for older age at diagnosis and for myeloid rather than lymphoid leukaemia. There are differences across regions of birth but not forming any obvious pattern. Our results suggest the decline in risk we previously reported from the 1960s to the 2000s is linked to calendar year of birth or of cancer occurrence rather than the age of the power lines concerned. Finally, we update our previous analysis of magnetic fields to include later subjects.

Residential mobility and associated factors in relation to the assessment of exposure to naturally occurring radiation in studies of childhood cancer

Migration, that is the study subjects moving from one residential address to another, is a complication for epidemiological studies where exposures to the agent of interest depend on place of residence [corrected]. In this paper we explore migration in cases from a large British case-control study of childhood cancer and natural background radiation. We find that 44% of cases had not moved house between birth and diagnosis, and about two-thirds were living within 2 km of their residence at birth. The estimated dose at the diagnosis address was strongly correlated with that at the birth address, suggesting that use of just the birth address in this case-control study does not lead to serious bias in risk estimates. We also review other individual-based studies of naturally occurring radiation, with particular emphasis on those from Great Britain. Interview-based case-control and cohort studies can potentially establish full residential histories for study subjects and make direct measurements of radiation levels in the dwellings in question. However, in practice, because of study size and difficulties in obtaining adequate response rates, interview-based studies generally do not use full residential histories, and a substantial proportion of dose estimates often derive from models rather than direct measurements. More seriously, problems of incomplete response may lead to bias, not just to loss of power. Record-based case-control studies, which do not require direct contact with study subjects, avoid such problems, but at the expense of having only model-based exposure estimates that use databases of measurements.

Magnetic fields and childhood cancer: an epidemiological investigation of the effects of high-voltage underground cables

Epidemiological evidence of increased risks for childhood leukaemia from magnetic fields has implicated, as one source of such fields, high-voltage overhead lines. Magnetic fields are not the only factor that varies in their vicinity, complicating interpretation of any associations. Underground cables (UGCs), however, produce magnetic fields but have no other discernible effects in their vicinity. We report here the largest ever epidemiological study of high voltage UGCs, based on 52,525 cases occurring from 1962-2008, with matched birth controls. We calculated the distance of the mother's address at child's birth to the closest 275 or 400 kV ac or high-voltage dc UGC in England and Wales and the resulting magnetic fields. Few people are exposed to magnetic fields from UGCs limiting the statistical power. We found no indications of an association of risk with distance or of trend in risk with increasing magnetic field for leukaemia, and no convincing pattern of risks for any other cancer. Trend estimates for leukaemia as shown by the odds ratio (and 95% confidence interval) per unit increase in exposure were: reciprocal of distance 0.99 (0.95-1.03), magnetic field 1.01 (0.76-1.33). The absence of risk detected in relation to UGCs tends to add to the argument that any risks from overhead lines may not be caused by magnetic fields.

Infant birthweight and risk of childhood cancer: international population-based case control studies of 40 000 cases

BACKGROUND

High birthweight is an established risk factor for childhood leukaemia. Its association with other childhood cancers is less clear, with studies hampered by low case numbers.

METHODS

We used two large independent datasets to explore risk associations between birthweight and all subtypes of childhood cancer. Data for 16 554 cases and 53 716 controls were obtained by linkage of birth to cancer registration records across five US states, and 23 772 cases and 33 206 controls were obtained from the UK National Registry of Childhood Tumours. US, but not UK, data were adjusted for gestational age, birth order, plurality, and maternal age and race/ethnicity.

RESULTS

Risk associations were found between birthweight and several childhood cancers, with strikingly similar results between datasets. Total cancer risk increased linearly with each 0.5 kg increase in birthweight in both the US [odds ratio 1.06 (95% confidence interval 1.04, 1.08)] and UK [1.06 (1.05, 1.08)] datasets. Risk was strongest for leukaemia [USA: 1.10 (1.06, 1.13), UK: 1.07 (1.04, 1.10)], tumours of the central nervous system [USA: 1.05 (1.01, 1.08), UK: 1.07 (1.04, 1.10)], renal tumours [USA: 1.17 (1.10, 1.24), UK: 1.12 (1.06, 1.19)] and soft tissue sarcomas [USA: 1.12 (1.05, 1.20), UK: 1.07 (1.00, 1.13)]. In contrast, increasing birthweight decreased the risk of hepatic tumours [USA: 0.77 (0.69, 0.85), UK: 0.79 (0.71, 0.89) per 0.5 kg increase]. Associations were also observed between high birthweight and risk of neuroblastoma, lymphomas, germ cell tumours and malignant melanomas. For some cancer subtypes, risk associations with birthweight were non-linear. We observed no association between birthweight and risk of retinoblastoma or bone tumours.

CONCLUSIONS

Approximately half of all childhood cancers exhibit associations with birthweight. The apparent independence from other factors indicates the importance of intrauterine growth regulation in the aetiology of these diseases.

Relative accuracy of grid references derived from postcode and address in UK epidemiological studies of overhead power lines

In the UK, the location of an address, necessary for calculating the distance to overhead power lines in epidemiological studies, is available from different sources. We assess the accuracy of each. The grid reference specific to each address, provided by the Ordnance Survey product Address-Point, is generally accurate to a few metres, which will usually be sufficient for calculating magnetic fields from the power lines. The grid reference derived from the postcode rather than the individual address is generally accurate to tens of metres, and may be acceptable for assessing effects that vary in the general proximity of the power line, but is probably not acceptable for assessing magnetic-field effects.

Childhood cancer and exposure to corona ions from power lines: an epidemiological test

We previously reported an association between childhood leukaemia in Britain and proximity of the child's address at birth to high-voltage power lines that declines from the 1960s to the 2000s. We test here whether a 'corona-ion hypothesis' could explain these results. This hypothesis proposes that corona ions, atmospheric ions produced by power lines and blown away from them by the wind, increase the retention of airborne pollutants in the airways when breathed in and hence cause disease. We develop an improved model for calculating exposure to corona ions, using data on winds from meteorological stations and considering the whole length of power line within 600 m of each subject's address. Corona-ion exposure is highly correlated with proximity to power lines, and hence the results parallel the elevations in leukaemia risk seen with distance analyses. But our model explains the observed pattern of leukaemia rates around power lines less well than straightforward distance measurements, and ecological considerations also argue against the hypothesis. This does not disprove the corona-ion hypothesis as the explanation for our previous results, but nor does it provide support for it, or, by extension, any other hypothesis dependent on wind direction.

Updated investigations of cancer excesses in individuals born or resident in the vicinity of Sellafield and Dounreay

BACKGROUND

Earlier studies have shown raised risks of leukaemia and non-Hodgkin lymphoma in children, teenagers and young adults resident either at birth or diagnosis in Seascale. Some increases in cancer risk in these age groups have also been noted among those living around Dounreay. We aimed to update previous analyses relating to areas close to these nuclear installations by considering data from an additional 16 years of follow-up.

METHODS

Cross-sectional analyses compared cancer incidence rates for 1963-2006 among those aged 0-24 years at diagnosis living in geographically specified areas around either Sellafield or Dounreay with general population rates. Cancer incidence for the period 1971-2006 among the cohort of Cumbrian births between 1950 and 2006 was compared to national incidence for 1971-2006 using person-years analysis. Cancer among those born in the postcode sector closest to Dounreay was compared with that among those born in the three adjoining postcode sectors. Analyses considered both cancer overall and ICD-O-3 defined diagnostic subgroups including leukaemia, central nervous system tumours and other malignancies.

RESULTS

Apart from previously reported raised risks, no new significantly increased risks for cancer overall or any diagnostic subgroup were found among children or teenagers and young adults living around either nuclear installation. Individuals born close to the installations from 1950 to 2006 were not shown to be at any increased risk of cancer during the period 1971 to date.

CONCLUSIONS

Analysis of recent data suggests that children, teenagers and young adults currently living close to Sellafield and Dounreay are not at an increased risk of developing cancer. Equally, there is no evidence of any increased cancer risk later in life among those resident in these areas at birth.

Residential distance at birth from overhead high-voltage powerlines: childhood cancer risk in Britain 1962-2008

Background:

We extend our previous study of childhood leukaemia and proximity to high-voltage powerlines by including more recent data and cases and controls from Scotland, by considering 132-kV powerlines as well as 275 and 400 kV and by looking at greater distances from the powerlines.

Methods:

Case–control study using 53 515 children from the National Registry of Childhood Tumours 1962–2008, matched controls, and calculated distances of mother's address at child's birth to powerlines at 132, 275, and 400 kV in England, Wales and Scotland.

Results:

Our previous finding of an excess risk for leukaemia at distances out to 600 m declines over time. Relative risk and 95% confidence interval for leukaemia, 0–199 m compared with>1000 m, all voltages: 1960s 4.50 (0.97–20.83), 2000s 0.71 (0.49–1.03), aggregate over whole period 1.12 (0.90–1.38). Increased risk, albeit less strong, may also be present for 132-kV lines. Increased risk does not extend beyond 600 m for lines of any voltage.

Conclusions:

A risk declining over time is unlikely to arise from any physical effect of the powerlines and is more likely to be the result of changing population characteristics among those living near powerlines.

Cancer risk among children born after assisted conception

BACKGROUND

Accurate population-based data are needed on the incidence of cancer in children born after assisted conception.

METHODS

We linked data on all children born in Britain between 1992 and 2008 after assisted conception without donor involvement with data from the United Kingdom National Registry of Childhood Tumours to determine the number of children in whom cancer developed before 15 years of age. Cohort cancer rates were compared with population-based rates in Britain over the same period, with stratification for potential mediating and moderating factors, including sex, age at diagnosis, birth weight, singleton versus multiple birth, parity, parental age, type of assisted conception, and cause of parental infertility.

RESULTS

The cohort consisted of 106,013 children born after assisted conception (700,705 person-years of observation). The average duration of follow-up was 6.6 years. Overall, 108 cancers were identified, as compared with 109.7 expected cancers (standardized incidence ratio, 0.98; 95% confidence interval [CI], 0.81 to 1.19; P=0.87). Assisted conception was not associated with an increased risk of leukemia, neuroblastoma, retinoblastoma, central nervous system tumors, or renal or germ-cell tumors. It was associated with an increased risk of hepatoblastoma (standardized incidence ratio, 3.64; 95% CI, 1.34 to 7.93; P=0.02; absolute excess risk, 6.21 cases per 1 million person-years) and rhabdomyosarcoma (standardized incidence ratio, 2.62; 95% CI, 1.26 to 4.82; P=0.02; absolute excess risk, 8.82 cases per 1 million person-years), with hepatoblastoma developing in 6 children and rhabdomyosarcoma in 10 children. The excess risk of hepatoblastoma was associated with low birth weight.

CONCLUSIONS

There was no increase in the overall risk of cancer among British children born after assisted conception during the 17-year study period. Increased risks of hepatoblastoma and rhabdomyosarcoma were detected, but the absolute risks were small. (Funded by Cancer Research UK and others.).

Familial aggregation of childhood and adult cancer in the Utah genealogy

A small proportion of childhood cancer is attributable to known hereditary syndromes, but whether there is any familial component to the remainder remains uncertain. We explored familial aggregation of cancer in a population-based case-control study using genealogical record linkage and designed to overcome limitations of previous studies. Subjects were selected from the Utah Population Database. We compared risk of cancer in adult first-degree relatives of children who were diagnosed with cancer with the risk in relatives of children who had not had a cancer diagnosed. We identified 1,894 childhood cancer cases and 3,788 controls; 7,467 relatives of cases and 14,498 relatives of controls were included in the analysis. Relatives of children with cancer had a higher risk of cancer in adulthood than relatives of children without cancer [odds ratio (OR) 1.31, 95% confidence interval (CI) 1.11-1.56]; this was restricted to mothers and siblings and was not evident in fathers. Familial aggregation appeared stronger among relatives of cases diagnosed before 5 years of age (OR 1.48, 95% CI 1.13-1.95) than among relatives of cases who were older when diagnosed (OR 1.22, 95% CI 0.98-1.51). These findings provide evidence of a generalized excess of cancer in the mothers and siblings of children with cancer. The tendency for risk to be higher in the relatives of children who were younger at cancer diagnosis should be investigated in other large data sets. The excesses of thyroid cancer in parents of children with cancer and of any cancer in relatives of children with leukemia merit further investigation.

Case-control study of paternal occupation and social class with risk of childhood central nervous system tumours in Great Britain, 1962-2006

BACKGROUND

Paternal occupational exposures have been proposed as a risk factor for childhood central nervous system (CNS) tumours. This study investigates possible associations between paternal occupational exposure and childhood CNS tumours in Great Britain.

METHODS

The National Registry of Childhood Tumours provided all cases of childhood CNS tumours born and diagnosed in Great Britain from 1962 to 2006. Controls without cancer were matched on sex, period of birth and birth registration sub-district. Fathers' occupations were assigned to one or more of 33 exposure groups. A measure of social class was also derived from father's occupation at the time of the child's birth.

RESULTS

Of 11 119 cases of CNS tumours, 5 722 (51%) were astrocytomas or other gliomas, 2 286 (21%) were embryonal and 985 (9%) were ependymomas. There was an increased risk for CNS tumours overall with exposure to animals, odds ratio (OR) 1.40 (95% confidence intervals (CIs) 1.01, 1.94) and, after adjustment for occupational social class (OSC), with exposure to lead, OR 1.18 (1.01, 1.39). Exposure to metal-working oil mists was associated with reduced risk of CNS tumours, both before and after adjustment for OSC, OR 0.87 (0.75, 0.99).Risk of ependymomas was raised for exposure to solvents, OR 1.73 (1.02,2.92). For astrocytomas and other gliomas, risk was raised with high social contact, although this was only statistically significant before adjustment for OSC, OR 1.15 (1.01,1.31). Exposure to paints and metals appeared to reduce the risk of astrocytomas and embryonal tumours, respectively. However, as these results were the result of a number of statistical tests, it is possible they were generated by chance.Higher social class was a risk factor for all CNS tumours, OR 0.97 (0.95, 0.99). This was driven by increased risk for higher social classes within the major subtype astrocytoma, OR 0.95 (0.91, 0.98).

CONCLUSION

Our results provide little evidence that paternal occupation is a significant risk factor for childhood CNS tumours, either overall or for specific subtypes. However, these analyses suggest that OSC of the father may be associated with risk of some childhood CNS cancers.

Second and subsequent tumours among 1927 retinoblastoma patients diagnosed in Britain 1951-2004

Background:

Retinoblastoma is an eye tumour of childhood that occurs in heritable and non-heritable forms. In the heritable form, there is a predisposition to the development of non-ocular subsequent primary tumours (SPTs).

Methods:

This study included 1927 retinoblastoma patients diagnosed in Britain from 1951 to 2004. Ascertainment was through the (UK) National Registry of Childhood Tumours; cases were followed-up for the occurrence of SPTs. Standardised incidence ratios (SIRs) were calculated.

Results:

We identified 169 SPTs in 152 patients. The SIR analysis included 145 SPTs with cancer registrations from the years 1971 to 2009. These tumours occurred in 132 patients: 112 of the 781 heritable and 20 of the 1075 (presumed) non-heritable cases under surveillance at the start of this period developed at least one registered SPT. The SIRs for all tumours combined were 13.7 (95% confidence interval 11.3–16.5) in heritable cases and 1.5 (0.9–2.3) in non-heritable cases. The main types of SPT in the heritable cases were leiomyosarcoma, (31 cases; SIR 1018.7 (692.2–1446.0)), osteosarcoma (26 cases; SIR 444.6 (290.4–651.4)), and skin melanoma (12 cases; SIR 18.6 (9.6–32.4)).

Conclusion:

The risk of SPTs in heritable retinoblastoma is extremely high. This has important implications for the clinical follow-up and counselling of survivors and their families.

Immunophenotype and cytogenetic characteristics in the relationship between birth weight and childhood leukemia

BACKGROUND

High birth weight increases the risk of childhood acute lymphoid leukemia (ALL) through unknown mechanisms. Whether this risk is specific to ALL subtypes is unknown, and low case numbers have prevented investigation of the rarer leukemias. Here we address these associations using a large population-based dataset.

PROCEDURE

Using the National Registry of Childhood Tumors, birth weights of 7,826 leukemia cases, defined by immunophenotype and cytogenetic subgroup, were compared with those of 10,785 controls born in England and Wales between 1980 and 2007.

RESULTS

The risk for overall leukemia increases 7% with each 0.5 kg increase in birth weight (OR 1.07, 95%CI 1.04-1.10). This risk is limited to the lymphoid leukemias (OR 1.08, 95%CI 1.05-1.12) diagnosed between 1 and 9 years of age. Analysis by cytogenetic feature reveals that there appears to be association with specific chromosomal abnormality: the risk of tumors with high hyperdiploid karyotypes increases 12% per 0.5 kg increase in birth weight (OR 1.12, 95%CI 1.05-1.20), and t(1;19) tumors show an increased risk of 41% per 0.5 kg increase (OR 1.41, 95%CI 1.09-1.84). The risk of acute myeloid leukemia is elevated in high and low birth weight babies. There is no significant risk relationship to other leukemias or myeloproliferative diseases.

CONCLUSIONS

Birth weight is a risk factor for ALL and AML. Other subtypes of the disease are not significantly affected. There appears to be association with specific chromosomal abnormality, which may aid our understanding of the development of childhood leukemia in utero.

Paternal occupation and neuroblastoma: a case-control study based on cancer registry data for Great Britain 1962-1999

BACKGROUND

Neuroblastoma is the most common malignancy of infancy but little is known about the aetiological factors associated with the development of this tumour. A number of epidemiological studies have previously examined the risk associated with paternal occupational exposures but most have involved small numbers of cases. Here we present results from a large, population-based, case-control study of subjects diagnosed over a period of more than 30 years and recorded in the national registry of childhood tumours in Great Britain.

METHODS

A case-control study of paternal occupational data for 2920 cases of neuroblastoma, born and diagnosed in Great Britain between 1962 and 1999 and recorded in the National Registry of Childhood Tumours, and 2920 controls from the general population matched on sex, date of birth and birth registration district. Paternal occupations at birth, of the case or control child, were grouped by inferred exposure using an occupational exposure classification scheme. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CI), for each of the 32 paternal occupational exposure groups.

RESULTS

Only paternal occupational exposure to leather was statistically significantly associated with neuroblastoma, OR=5.00 (95% CI 1.07-46.93). However, this association became non-significant on correction for multiple testing.

CONCLUSION

Our findings do not support the hypothesis that paternal occupational exposure is an important aetiological factor for neuroblastoma.

Paternal occupation and retinoblastoma: a case-control study based on data for Great Britain 1962-1999

OBJECTIVES

To examine the association between paternal occupational exposures and retinoblastoma using birth registration data for cases from the National Registry of Childhood Tumours (NRCT) and controls from the general population of Great Britain.

METHODS

A case-control study of paternal occupational data for 1318 cases of retinoblastoma, born and diagnosed in Great Britain between 1962 and 1999, and 1318 controls matched on sex, date of birth and birth registration sub-district. Paternal occupations at birth were grouped according to inferred exposure using an occupational exposure classification scheme. A conditional (matched) case-control analysis was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for each paternal occupational exposure group.

RESULTS

For non-heritable retinoblastoma, a statistically significant increased risk was found with father's definite occupational exposure to oil mists in metal working (OR = 1.85 (95% CI 1.05 to 3.36)). Together with a (non-significant) risk (OR = 1.64 (0.73 to 3.83)) amongst the heritable cases, this occupational exposure was also associated with a significant increased risk when all retinoblastoma cases were considered together (OR = 1.77 (1.12 to 2.85)). No statistically significant associations were observed for other exposure groups.

CONCLUSIONS

Our finding for exposure to oil mists in metal working (a subset of metal workers) is not directly comparable to those for metal working previously reported in the literature. Overall, our findings do not support the hypothesis that paternal occupational exposure is an important aetiological factor for retinoblastoma, however, the study has low power and other methodological limitations.

Wilms tumour and paternal occupation: an analysis of data from the National Registry of Childhood Tumours

BACKGROUND

Wilms tumour is an embryonal malignant tumour that accounts for 90% of childhood kidney cancers. Parental occupational exposure has been hypothesised to be a cause of childhood Wilms tumour, in particular exposure to pesticides. However, the findings are inconsistent.

PROCEDURE

We have examined the association between paternal occupational exposures and Wilms tumour using birth registration data for cases (n = 2568) from the National Registry of Childhood Tumours (NRCT) and matched controls (n = 2,568) drawn from the general population of Great Britain. Paternal occupation, as recorded at the time of birth, was used to infer "occupational exposure" using a previously defined occupational exposure classification scheme. Odds ratios and 95% confidence intervals were generated using conditional logistic regression with exact methods to estimate the association between each paternal occupational exposure group and childhood Wilms tumour.

RESULTS

All odds ratios were close to 1.00 and no statistically significant associations were observed.

CONCLUSION

The results of this study failed to support any of the previously identified associations between paternal occupation and childhood Wilms tumour.

Reduced occurrence of childhood cancer in twins compared to singletons: protection but by what mechanism?

BACKGROUND

Several small studies combined have suggested that twins develop fewer childhood cancers than singletons. The national Swedish Family-Cancer Database contains information on a large population of multiple births providing an unbiased dataset for the estimation of cancer risk in twins. Lifelong cancer incidence in these twins has already been reported as similar to that in singleton births. In contrast, the present paper presents robust estimates of a significantly reduced childhood cancer risk in twins to age 15.

METHODS

Standardised incidence ratios (SIR) were used to measure cancer risk for twins, taking the corresponding rates for singletons as reference. Rates were adjusted for age, sex, period of birth, and residential area. Follow up data cover the period 1958-2002.

RESULTS

Overall childhood cancer risk was significantly reduced in all twins (SIR 0.81 [95% CI: 0.69-0.94]) as was the risk for Wilms tumour (SIR 0.34 [95% CI: 0.09-0.88]). These significant reductions in risk were both driven by effects in same sex twins (overall cancer SIR 0.77 [95% CI: 0.64-0.93], Wilms tumour 0.12 [95% CI: 0.00-0.71]). Leukaemia risk was also significantly reduced for same sex twins (SIR 0.69 [95% CI: 0.47-0.97]).

CONCLUSIONS

Our study provides the evidence that twins experience less childhood cancer than singletons. The risk reduction is most marked for Wilms tumour but may, to a varying extent, be true for a number of childhood neoplasms.

Cancer in the offspring of radiation workers: an investigation of employment timing and a reanalysis using updated dose information

An earlier case–control study found no evidence of paternal preconceptional irradiation (PPI) as a cause of childhood leukaemia and non-Hodgkin's lymphoma (LNHL). Although fathers of children with LNHL were more likely to have been radiation workers, the risk was most marked in those with doses below the level of detection. The timing of paternal employment as a radiation worker has now been examined. The previously reported elevated risk of LNHL in the children of male radiation workers was limited to those whose fathers were still radiation workers at conception or whose employment also continued until diagnosis. Children whose fathers stopped radiation work prior to their conception were found to have no excess risk of LNHL. It was not possible to distinguish between the risks associated with paternal radiation work at conception and at the time of diagnosis. A reanalysis of the original study hypothesis incorporating updated dosimetric information gave similar results to those obtained previously. In particular, the risks of LNHL did not show an association with radiation doses received by the father before conception. It seems likely that the increased risk of LNHL among the children of male radiation workers is associated with an increased exposure to some infective agent consequent on high levels of population mixing.

Case-control study of parental age, parity and socioeconomic level in relation to childhood cancers

BACKGROUND

Parental ages, parity, and social class have been found in some studies to be associated with particular childhood cancers. Further investigation is warranted because of conflicting findings, biases, and the need to test specific hypotheses.

METHODS

A case-control study was conducted (England and Wales, ages 0-14 years). Cases were ascertained from the National Registry of Childhood Tumours, and were born and diagnosed during 1968-1986. Birth record controls were matched 1:1 to cases on date of birth, sex and area. Information on variables of interest for both groups came from birth records. In all, 10 162 pairs could contribute to matched analyses.

RESULTS

The odds ratio (OR) for retinoblastoma resulting from assumed new germ cell mutations among children of fathers aged > or =45 years was 3.0 (95% CI : 0.2-41.7). The risk of childhood acute lymphoblastic leukaemia (ALL) was significantly higher among children of older mothers and fathers, and significant trends with increasing mothers' (P < 0.001) and fathers' (P = 0.002) ages were found. There was a strong and significant protective effect of increasing parity on risk of childhood ALL. The adjusted OR for parity of > or =5 (versus 0) was 0.5 (95% CI : 0.3-0.8). Children in more deprived communities had a lower risk of ALL; but this was not significant after confounders were allowed for. There was no significant effect of social class based on parental occupation on ALL risk, but the numbers were small in those analyses.

CONCLUSIONS

The associations between ALL and parental ages did not disappear when children with Down syndrome were excluded, suggesting an additional explanation beyond known links. The strong ALL association with parity may be because of an unknown environmental risk factor.

Ethnic group and survival from childhood cancer: report from the UK Children's Cancer Study Group

Survival following cancer was analysed in relation to ethnic group among children diagnosed in Britain during 1981-1996 and treated at paediatric oncology centres by members of the UK Children's Cancer Study Group. Survival was analysed for 11 diagnostic groups: acute lymphoblastic leukaemia (ALL), acute non-lymphocytic leukaemia, Hodgkin's disease, non-Hodgkin's lymphoma, astrocytoma, primitive neuroectodermal tumour, neuroblastoma, Wilms' tumour, osteosarcoma, Ewing's sarcoma and rhabdomyosarcoma. There were no significant differences in survival between White and non-White children over the study period as a whole. Among children with ALL, however, the relative risk of death allowing for period of diagnosis, age and white blood count was 1.25 for those of South Asian ethnic origin compared with Whites (P = 0.057).

Cancer in the offspring of radiation workers: a record linkage study

OBJECTIVES

To test the "Gardner hypothesis" that childhood leukaemia and non-Hodgkin lymphoma can be caused by fathers' exposure to ionising radiation before the conception of the child, and, more generally, to investigate whether such radiation exposure of either parent is a cause of childhood cancer.

DESIGN

Case-control study.

SETTING

Great Britain.

SUBJECTS

35,949 children diagnosed as having cancer, together with matched controls.

MAIN OUTCOME MEASURES

Parental employment as radiation worker as defined by inclusion in the National Registry for Radiation Workers and being monitored for external radiation before conception of child; cumulative dose of external ionising radiation for various periods of employment before conception; dose during pregnancy.

RESULTS

After cases studied by Gardner and colleagues were excluded, fathers of children with leukaemia or non-Hodgkin lymphoma were significantly more likely than fathers of controls to have been radiation workers (relative risk 1.77, 95% confidence interval 1.05 to 3.03) but there was no dose-response relation for any of the exposure periods studied; indeed, the association was greatest for those with doses below the level of detection. No increased risk was found for fathers with a lifetime preconception dose of 100 mSv or more, or with a dose in the 6 months before conception of 10 mSv or more. There was no increased risk for the group of other childhood cancers. Mothers' radiation work was associated with a significant increase of childhood cancer (relative risk 5.00, 1.42 to 26.94; based on 15 cases and 3 controls). Only four of the case mothers and no controls were radiation workers during pregnancy.

CONCLUSIONS

These results do not support the hypothesis that paternal preconception irradiation is a cause of childhood leukaemia and non-Hodgkin lymphoma; the observed associations may be chance findings or results from exposure to infective or other agents. If there is any increased risk for the children of fathers who are radiation workers, it is small in absolute terms: in Britain the average risk by age 15 years is 6.5 per 10,000; our best estimate, using all available data, is that the increase is 5.4 per 10,000. For mothers, the numbers are too small for reliable estimates of the risk, if any, to be made.

Brain and spinal tumours in children aged under two years: incidence and survival in Britain, 1971-85

There were 548 children aged under two with brain and spinal tumours diagnosed during 1971-85 in Great Britain and included in the population-based National Registry of Childhood Tumours. Children aged under two accounted for 12% of all children registered with tumours in these sites. The annual incidence was 25.0 per million. Ependymoma, astrocytoma and medulloblastoma (including primitive neuroectodermal tumour) each accounted for around a quarter of the total. Five-year survival rates were 20% for ependymoma, 43% for astrocytoma and 13% for medulloblastoma, each significantly lower than for children aged 2-14 in the corresponding diagnostic group. Mortality in the first year after diagnosis was very high but there were also substantial numbers of later deaths. There was no significant trend in survival rates during the period under review.

Incidence of leukaemia and other cancers in birth and schools cohorts in the Dounreay area

OBJECTIVE

To determine whether a raised incidence of leukaemia in the Dounreay area occurred in children born to local mothers (birth cohort) or in those who moved to the area after birth (schools cohort) and also whether any cases of cancer have occurred in children born near Dounreay who may have moved elsewhere.

DESIGN

Follow up study.

SETTING

Dounreay area of Caithness, Scotland.

SUBJECTS

4144 children born in the area in the period 1969-88 and 1641 children who attended local schools in the same period but who had been born elsewhere.

MAIN OUTCOME MEASURES

Cancer registration records linked to birth and school records with computerised probability matching methods.

RESULTS

Five cancer registrations were traced from the birth cohort compared with 5.8 expected on the basis of national rates (observed to expected ratio 0.9, 95% confidence interval 0.3 to 2.0). All five cases were of leukaemia (2.3, 0.7 to 5.4). In the schools cohort three cases were found (2.1, 0.4 to 6.2), all of which were of leukaemia (6.7, 1.4 to 19.5). All eight children were resident in the Dounreay area at the time of diagnosis; thus no cases were found in children who were born in or had attended school in the study area but who subsequently moved away.

CONCLUSION

The raised incidence of leukaemia in both the birth and schools cohorts suggests that place of birth is not a more important factor than place of residence in the series of cases of leukaemia observed near Dounreay area.

Childhood cancer and ethnic group in Britain: a United Kingdom children's Cancer Study Group (UKCCSG) study

We present here the results of the largest study of childhood cancer and ethnic group in Britain, based on 7,658 children treated at paediatric oncology centres throughout the country. Incidence rates could not be calculated and so relative frequencies were analysed by the log-linear modelling method of Kaldor et al. (1990) with allowance made for regional variations in the ages and diagnostic groups of the children included in the study. Children of Asian (Indian sub-continent) and West Indian ethnic origin had similar patterns of incidence for acute lymphoblastic leukaemia to White Caucasians. There was a significant excess of Hodgkin's disease among Asian children compared with Caucasians with an estimated relative risk (RR) of 2.09; this excess was greatest in the 0-4 age group (RR = 6.67). There were significant deficits of Wilms' tumour and rhabdomyosarcoma among Asian children, each with a frequency around half that among Caucasians, whereas West Indians had a significant excess of Wilms' tumour (RR = 2.55). Asian and West Indian children each had a non-significant twofold RR for unilateral retinoblastoma. The results suggest that the incidence of childhood acute lymphoblastic leukaemia is associated with environmental determinants in the country of residence which are most likely to relate to lifestyle factors. The occurrence of retinoblastoma, Wilms' tumour and Hodgkin's disease in early childhood is apparently related more to ethnicity than to geographical location and may reflect genetic factors or environmental exposures specific to the lifestyle of particular ethnic groups.

Trends in survival for childhood cancer in Britain diagnosed 1971-85

Survival rates were analysed for a population-based series of over 15,000 childhood cancers registered in Great Britain during 1971-85. There were highly significant improvements (P less than 0.001 for trend) in survival for many major diagnostic groups. Between 1971-73 and 1983-85 the actuarial 5-year survival rates increased from 37% to 70% for acute lymphoblastic leukaemia, from 4% to 26% for acute non-lymphoblastic leukaemia, from 76% to 88% for Hodgkin's disease, from 22% to 70% for non-Hodgkin's lymphoma, from 61% to 72% for astrocytoma, from 24% to 42% for medulloblastoma, from 15% to 43% for neuroblastoma, from 58% to 79% for Wilms' tumour, from 17% to 54% for osteosarcoma, from 26% to 61% for rhabdomyosarcoma, from 59% to 94% for malignant testicular germ-cell tumours and from 43% to 77% for malignant ovarian germ-cell tumours. These increases in population-based survival rates reflect the substantial advances in treatment of a wide range of childhood cancers since 1970. The two principal diagnostic groups for which there was no evidence of any trend were retinoblastoma, which already had an excellent prognosis with a 5-year survival rate of over 85%, and Ewing's sarcoma, for which the survival rate remained below 45%.

Effects of dietary change and rotavirus infection on small intestinal structure and function in gnotobiotic piglets

The combined effects of weaning and rotavirus infection on small intestinal structure and function and on growth rate were studied in 28 gnotobiotic piglets. There was little damage by rotavirus to the proximal small intestine, some damage to the mid small intestine and relatively severe damage to the distal small intestine; villi were stunted, crypts lengthened and activities of all brush border enzymes decreased. The damage was short-lived despite the synchronisation of rotavirus infection with simulated weaning. There was no evidence of persistent damage to the small intestine and growth rate was unaffected.

The influence of extracellular and phagolysosomal pH changes on the bactericidal activity of bovine neutrophils against Staphylococcus aureus

The influence of the pH of suspending medium on bovine neutrophil (PMN) function was assessed in tests of phagocytosis and killing of Staphylococcus aureus. Intracellular killing was markedly inhibited by moderate extracellular acidification whereas phagocytosis was little affected, except at the lowest pH level (pH 5.0). The killing of S. aureus by extracts of isolated PMN lysosomal granules showed a similar pH dependence and was optimal at pH levels above neutrality. Survival of S. aureus within PMN from different cows varied significantly and the relative differences in PMN bactericidal efficiency were maintained at all pH levels. The acidification of extracellular medium during incubation which resulted from metabolic activity of the PMN themselves, increased with increasing ratios of bacteria:PMN and varied significantly among cows. Addition of methylamine (10 mM) to elevate phagolysosomal pH inhibited phagocytosis and had no effect on intracellular survival of S. aureus. However, a lower concentration (1.5 mM) did not affect phagocytosis, but reduced bacterial survival without altering the relative differences in efficiency of PMN from different cows. It is suggested that the acidity of the extracellular medium may both reflect and influence the pH changes occurring within PMN phagosomes and, thereby, modulate the efficiency of intracellular destruction of S. aureus.

Microbiology of calf diarrhoea in southern Britain

Faeces samples from calves with diarrhoea in 45 outbreaks were examined for six enteropathogens. Rotavirus and coronavirus were detected by ELISA in 208 (42 per cent) and 69 (14 per cent) of 490 calves respectively; calici-like viruses were detected by electron microscopy in 14 of 132 calves (11 per cent). Cryptosporidium were detected in 106 of 465 (23 per cent), Salmonella species in 58 of 490 (12 per cent) and enterotoxigenic Escherichia coli bearing the K99 adhesin (K99+ E coli) in nine of 310 calves (3 per cent). In the faeces of 20 per cent of calves with diarrhoea more than one enteropathogen was detected; in 31 per cent no enteropathogen was found. Faces samples from 385 healthy calves in the same outbreaks were also examined. There was a significant statistical association of disease with the presence of rotavirus, coronavirus, Cryptosporidium and Salmonella species (P less than 0.001). Healthy calves were not examined for calici-like viruses and the association of K99+ E coli with disease was not analysed because there were too few positive samples. Rotavirus infections were more common in dairy herds and single suckler beef herds whereas Salmonella infections were more often found in calf rearing units. Cryptosporidium were more common in single and multiple suckler beef herds. K99+ E coli were found in one dairy herd and one multiple suckler beef herd both with unhygienic calving accommodation. Variations in coronavirus detection among different farm types were not statistically significant. In this survey rotavirus was the most commonly detected agent in calf diarrhoea and Cryptosporidium were found in approximately one quarter of affected calves. Infection with Salmonella species was widespread, but K99+ E coli infections were less common in the United Kingdom than in other countries.