Radiation doses to members of the public near to Sellafield, Cumbria, from liquid discharges 1952-98.

Liquid wastes containing low levels of radioactivity have been discharged to the Irish Sea from the nuclear fuel reprocessing site at Sellafield since operations began in the early 1950s, and monitoring of radioactivity in foodstuffs has been undertaken over many years. Based on the best available monitoring data, supplemented by modelled values where necessary, doses to local critical groups have been reassessed using the most recent dosimetry. Contemporary habits data have been used where available, again supplemented by assumed habits where necessary. During the 1950s and 1960s the highest doses were received by individuals consuming Cumbrian Porphyra as laverbread, and peak doses around 0.8 to 1.0 mSv year(-1) have been estimated. During the 1970s and 1980s the critical exposure group switched to consumers of local fish and shellfish, with peak doses possibly reaching 2.5 to 3.0 mSv year(-1). Latterly, doses to all marine-related groups have declined to less than 150 to 200 microSv year(-1). At all times, doses have been within the appropriate limits set for members of the public.     

Detection and assessment of clusters of disease: An application to nuclear power plant facilities and childhood leukaemia in Sweden

We review some recent statistical methods for examining geographic patterns of disease incidence for the presence of clusters. General methods search for clusters throughout the study area and then assess the statistical significance of any clusters detected. Focused methods check for elevated incidence rates close to prespecified locations of putative sources of hazard. We apply the methods to leukaemia incidence data for children aged 0–15 years in Sweden (1980–1990), particularly in reference to locations of nuclear power facilities. Unlike some other studies, notably in the United Kingdom, we do not find any significant clusters.     

A procedure for detecting childhood cancer clusters near hazardous waste sites in Florida

Despite over 20 years of research on childhood cancer clusters and hazardous waste sites, little evidence has been produced to indicate a causal relationship. Nevertheless, the perception of a childhood cancer cluster being located near a hazardous waste site can raise fear and uncertainty, and it demands attention from health officials. To investigate this public health concern, the author used the spatial-scan statistical software SaTScan to detect childhood cancer clusters and their proximity to National Priority List (NPL), or Superfund, sites in Florida. In the ecological study reported here, "most likely" clusters were defined as those with a p-value of < .05. Distance served as a proxy for exposure; a geographical information system (GIS) was used to determine the number of clusters within a predetermined distance of an NPL site. Spatial clusters were found to occur randomly throughout the state, with most clusters being identified in the more populated counties, and clusters less likely to occur near an NPL site. This article attempts to explain the utility of an emerging public health surveillance tool for detecting cancer clusters near hazardous waste sites. Despite several epidemiological limitations of the study, as well as the fact that there are other environmental exposure hazards such as Toxic Release Inventory facilities and landfills, the SaTScan program proved useful as a surveillance tool for generating more in-depth studies.     

Residential exposure to electromagnetic fields and childhood leukaemia: a meta-analysis

Although individual epidemiological investigations have suggested associations between residential exposure to electromagnetic fields (EMFs) and childhood leukaemia, overall the findings have been inconclusive. Several of these studies do, however, lend themselves to application of the meta-analysis technique. For this purpose we carried out searches using MEDLINE and other sources, and 14 case-control studies and one cohort study were identified and evaluated for epidemiological quality and included in the meta-analysis. Relative risk estimates were extracted from each of the studies and pooled. Separate meta-analyses were performed on the basis of the assessed EMF exposure (wiring configuration codes, distance to power distribution equipment, spot and 24-h measures of magnetic field strength (magnetic flux density) and calculated magnetic field). The meta-analysis based on wiring configuration codes yielded a pooled relative risk estimate of 1.46 (95% confidence interval (CI) = 1.05-2.04, P = 0.024) and for that for exposure to 24-h measurements of magnetic fields, 1.59 (95% CI = 1.14-2.22, P = 0.006), indicating a potential effect of residential EMF exposure on childhood leukaemia. In most cases, lower risk estimates were obtained by pooling high-quality studies than pooling low-quality studies. There appears to be a clear trend for more recent studies to be of higher quality. Enough evidence exists to conclude that dismissing concerns about residential EMFs and childhood leukaemia is unwarranted. Additional high-quality epidemiological studies incorporating comparable measures for both exposure and outcomes are, however, needed to confirm these findings and, should they prove to be true, the case options for minimizing exposure should be thoroughly investigated to provide definitive answers for policy-makers.     

Socioeconomic status and childhood leukaemia: a review

BACKGROUND: A long-held view links higher socioeconomic status (SES) to higher rates of childhood leukaemia. Some recent studies exhibit associations in the opposite direction. METHODS: We reviewed journal literature through August 2002 for associations between childhood leukaemia and socioeconomic measures. We determined the direction of each association and its P-value. We described the results with regard to study design, calendar period, geographic locale, and level of the socioeconomic measures (individual or ecological). For measures with sufficient number of results, we computed summary P-values across studies. RESULTS: Case-control studies conducted in North America since 1980 have involved subject interviews or self-administered questionnaires and have consistently reported inverse (negative) associations of childhood leukaemia with individual-level measures of family income, mother's education, and father's education. In contrast, associations have been consistently positive with father's occupational class in record-based case-control studies and with average occupational class in ecological studies. CONCLUSIONS: Connections of SES measures to childhood leukaemia are likely to vary with place and time. Validation studies are needed to estimate SES-related selection and participation in case-control studies. Because different socioeconomic measures (such as income and education) and individual-level and ecological-level measures may represent different risk factors, we advise researchers to report these measures separately rather than in summary indices of social class.     

Are maternal fertility problems related to childhood leukaemia?

An explorative case-control study was conducted in The Netherlands. The cases were obtained from a complete nationwide register of childhood leukaemia (1973-1980). Controls were matched with the cases for year of birth, sex and place of residence. Information about exposures of the mother to potential risk factors in the year before pregnancy and during pregnancy was collected via mailed questionnaires. The analyses concerned data on 519 patients with acute lymphocytic leukaemia and 507 controls. An association between maternal subfertility and childhood leukaemia might be suggested by several findings. A history of two or more miscarriages (OR 1.6; 95% Cl 1.0-2.7) and fertility problems (OR 6.0; 95% Cl 0.9-38.2) were more frequently reported among mothers of cases. The use of oral contraceptives (OC) was significantly higher (OR 1.3; 95% Cl 1.0-1.8) and the duration between discontinuation of OC and the relevant pregnancy was significantly longer. The OR for threatened abortion during the relevant pregnancy was 1.6 (95% Cl 1.0-2.6) and the related use of 'drugs to maintain pregnancy' was 1.9; 95% Cl 1.0-3.5. Among known risk factors, an increased OR for diagnostic irradiation was confirmed (OR 2.2; 95% Cl 1.2-3.8). No association between childhood leukaemia and prenatal viral infections, smoking and alcohol was found.     

Maternal and birth characteristics in relation to childhood leukaemia

Our objective was to investigate the association of childhood leukaemia with selected maternal and birth characteristics by conducting a population-based case-control study using linked cancer registry and birth certificate records for Washington State. We compared maternal and infant characteristics of 595 Washington-born residents <20 years old with leukaemia diagnosed during 1981-2003, and 5,950 control children, using stratified analysis and logistic regression. Maternal age 35+ years (odds ratio [OR] 1.5; 95% confidence interval [CI] 1.1, 2.0), infant birthweight 4,000+ g (OR 1.4; 95% CI 1.1, 1.8), neonatal jaundice (OR 1.5; 95% CI 1.1, 2.1), and Down's syndrome (OR 31.3; 95% CI 6.4, 153.4) were associated with an increased risk of leukaemia. Among women with 2+ pregnancies, having at least two prior early (<20 weeks' gestation) fetal deaths was also associated with an increased risk (OR 1.5; 95% CI 0.97, 2.1). Maternal unmarried status (OR 0.7; 95% CI 0.6, 0.9) and African American race (OR 0.5; 95% CI 0.3, 0.9) were associated with a decreased risk. These results were more marked for acute lymphocytic leukaemia (ALL) than for acute myeloid leukaemia (AML), and for leukaemia diagnosed <5 years of age. These results may provide clues to the aetiology of childhood leukaemia. Genetic epidemiological studies are needed to expand our knowledge of inherent and possibly prenatal influences on the occurrence of this disease.     

Household exposure to pesticides and risk of childhood acute leukaemia

Objectives

To investigate the relation between childhood acute leukaemia and household exposure to pesticides.

Methods

The study included 280 incident cases of acute leukaemia and 288 controls frequency matched on gender, age, hospital, and ethnic origin. The data were obtained from standardised face to face interviews of the mothers with detailed questions on parental occupational history, home and garden insecticide use, and insecticidal treatment of pediculosis. Odds ratios were estimated using unconditional regression models including the stratification variables parental socioeconomic status and housing characteristics.

Results

Acute leukaemia was observed to be significantly associated with maternal home insecticide use during pregnancy (OR = 1.8, 95% CI 1.2 to 2.8) and during childhood (OR = 1.7, 95% CI 1.1 to 2.4), with garden insecticide use (OR = 2.4, 95% CI 1.3 to 4.3), and fungicide use (OR = 2.5, 95% CI 1.0 to 6.2) during childhood. Insecticidal shampoo treatment of pediculosis was also associated with childhood acute leukaemia (OR = 1.9, 95% CI 1.2 to 3.3).

Conclusion

The results reported herein support the hypothesis that various types of insecticide exposure may be a risk factor for childhood acute leukaemia. The observed association with insecticidal shampoo treatment of pediculosis, which has never been investigated before, requires further study.     

Commentary: childhood cancer near nuclear power stations

In 2008, the KiKK study in Germany reported a 1.6-fold increase in solid cancers and a 2.2-fold increase in leukemias among children living within 5 km of all German nuclear power stations. The study has triggered debates as to the cause(s) of these increased cancers. This article reports on the findings of the KiKK study; discusses past and more recent epidemiological studies of leukemias near nuclear installations around the world, and outlines a possible biological mechanism to explain the increased cancers. This suggests that the observed high rates of infant leukemias may be a teratogenic effect from incorporated radionuclides. Doses from environmental emissions from nuclear reactors to embryos and fetuses in pregnant women near nuclear power stations may be larger than suspected. Hematopoietic tissues appear to be considerably more radiosensitive in embryos/fetuses than in newborn babies. Recommendations for advice to local residents and for further research are made.     

The integrated management of childhood illness: Haiti's example

Child health in developing countries is a public health priority both at the national and international level. The World Health Organization, UNICEF and other technical partners have developed The Integrated Management of Childhood Illness (IMCI) strategy to reduce child mortality and improve child health and development through a holistic approach. By the end of 2002, 109 countries among which 17 in the region of the Americas and Caribbean had adopted and implemented this strategy,. In this region, Haiti presents the highest mortality rate for under-fives. Every year, more than 138,000 children die of diseases such as malaria, pneumonia, diarrhea, measles and perinatal complications. Malnutrition contributes to a high percentage of these deaths. It is recognised that the mortality due to these diseases can be prevented. To fight this burden, Haiti officially adopted the IMCI strategy in 1997. The objectives of this paper are, after a general overview of the IMCI strategy, to describe Haiti's child health and analyse the achievements of the first steps of implementing the IMCI strategy in Haiti. The methodology used was a standardised literature review and a qualitative survey based on semi-structured interviews of national and local health authorities involved in the implementation of the IMCI strategy in Haiti. Main results show a limited impact of the first and second phase of implementation in the country. The key factors for this have been limited economical and human resources. A unequal distribution of existing resources between the different IMCI strategy components especially community and family practices, has limited adequate coverage. Isolated actions in favour of child health as well as a lack of co-ordinated interventions between the various actors have been among the barriers for an adequate implementation of this strategy. We recognise that the approach used here is not a formal evaluation on the implementation of IMCI in Haiti. Nevertheless, we hope this article will contribute to draw the attention of national and international public health decision-makers on the difficulties of implementing this strategy in Haiti and in this way, improve child health in the country.     

Disaggregation of collective dose--a worked example based on future discharges from the Sellafield nuclear fuel reprocessing site, UK.

Collective dose has long been advocated as an important measure of the detriment associated with practices that involve the use of radioactivity. Application of collective dose in the context of worker protection is relatively straightforward, whereas its application in the context of discharges to the environment can yield radically different conclusions depending upon the population groups and integration times that are considered. The computer program PC-CREAM98 has been used to provide an indicative disaggregation into individual dose bands of the collective dose due to potential future radioactive discharges from the nuclear fuel reprocessing site at Sellafield in the UK. Two alternative discharge scenarios are considered, which represent a 'stop reprocessing early, minimum discharge' scenario and a 'reprocessing beyond current contracts' scenario. For aerial discharges, collective dose at individual effective dose rates exceeding 0.015 microSv y(-1) is only incurred within the UK, and at effective dose rates exceeding 1.5 microSv y(-1) is only incurred within about 20 km of Sellafield. The geographical distribution of collective dose from liquid discharges is harder to assess, but it appears that collective dose incurred outside the UK is at levels of individual effective dose rate below 1.5 microSv y(-1), with the majority being incurred at rates of 0.002 microSv y(-1) or less. In multi-attribute utility analyses, the view taken on the radiological detriment to be attributed to the two discharge scenarios will depend critically on the weight or monetary value ascribed to collective doses incurred within the differing bands of individual dose rate.     

Leukaemia clusters in childhood: geographical analysis in Britain.

STUDY OBJECTIVE--To validate previously demonstrated spatial clustering of childhood leukaemias by showing relative proximities of selected map features to cluster locations, compared with control locations. If clusters are real, then they are likely to be close to a determining hazard. DESIGN--Cluster postcode loci and partially matched control postcodes were compared in terms of distances to railways, main roads, churches, surface water, woodland areas, and railside industrial installations. Further supporting comparisons between non-clustered cases and random postcode controls with those map features representable as single grid points were made. SETTING--England, Wales, and Scotland 1966-83. SUBJECTS--Grid referenced registrations of 9406 childhood leukaemias and non-Hodgkin's lymphomas, including 264 pairs (or more) separated by < 150 m, and grid references of random postcodes in equal numbers. MAIN RESULTS--The 264 clusters showed relative proximities (or the inverse) to several map features, of which the most powerful was an association with railways. The non-railway associations seemed to be statistically indirect. Some railside industrial installations, identified from a railway atlas, also showed relative proximities to leukaemia clusters, as well as to non-clustered cases, but did not "explain" the railway effect. These installations, with seemingly independent geographical associations, included oil refineries, petrochemical plants, oil storage and oil distribution depots, power stations, and steelworks. CONCLUSIONS--The previously shown childhood leukaemia clusters are confirmed to be non-random through their systematic associations with certain map features when compared with the control locations. The common patterns of close association of clustered and non-clustered cases imply a common aetiological component arising from a common environmental hazard--namely the use of fossil fuels, especially petroleum.     

Maternal alcohol and coffee drinking, parental smoking and childhood leukaemia: a French population-based case-control study

We investigated the role of maternal alcohol and coffee drinking during pregnancy and that of parental smoking in the aetiology of childhood leukaemia. A French, population-based, case-control study was conducted, comparing 472 [407 acute lymphoblastic leukaemia (ALL) and 62 acute myeloblastic leukaemia] cases of childhood acute leukaemia (AL) and 567 population controls, frequency-matched with cases on age, gender and region of residence. Both case and control mothers filled in a comprehensive self-administered standardised questionnaire, eliciting detailed data on maternal alcohol and coffee consumption during pregnancy and parental smoking before, during and after pregnancy. Maternal alcohol consumption of more than 1 drink per day was related to ALL (OR = 2.8 [95% CI 1.8, 5.9]). While maternal coffee consumption was not significantly related to AL (OR = 1.4 [95% CI 0.9, 2.3]), highest intake of coffee (more than 3 cups per day) during pregnancy was associated with AL in children whose mothers were non-smokers (OR = 1.9 [95% CI 1.0, 3.5]). No association with parental smoking, either maternal or paternal, was observed with AL. The present results suggest a possible role of the highest consumption of alcohol by the mother during pregnancy in the aetiology of childhood AL.     

To give or not to give: Approaches to early childhood immunization delivery in Oregon rural primary care practices

Context: Little is known about rural clinicians’ perspectives regarding early childhood immunization delivery, their adherence to recommended best immunization practices, or the specific barriers they confront. Purpose: To examine immunization practices, beliefs, and barriers among rural primary care clinicians for children in Oregon and compare those who deliver all recommended immunizations in their practices with those who do not. Methods: A mailed questionnaire was sent to all physicians, nurse practitioners, and physician assistants practicing primary care in rural communities throughout Oregon. Findings: While 39% of rural clinicians reported delivering all childhood immunizations in their clinic, 43% of clinicians reported that they refer patients elsewhere for some vaccinations, and 18% provided no immunizations in the clinic whatsoever. Leading reasons for referral include inadequate reimbursement, parental request, and storage and stocking difficulties. Nearly a third of respondents reported that they had some level of concern about the safety of immunizations, and 14% reported that concerns about safety were a specific reason for referring. Clinicians who delivered only some of the recommended immunizations were less likely than nonreferring clinicians to have adopted evidence‐based best immunization practices. Conclusions: This study of rural clinicians in Oregon demonstrates the prevalence of barriers to primary care based immunization delivery in rural regions. While some barriers may be difficult to overcome, others may be amenable to educational outreach and support. Thus, efforts to improve population immunization rates should focus on promoting immunization “best practices” and enhancing the capacity of practices to provide immunizations and ensuring that any alternative means of delivering immunizations are effective.