1
|
Bunch KJ, Kendall GM, Stiller CA, Vincent TJ, Murphy MFG. Case-control study of paternal occupational exposures and childhood lymphoma in Great Britain, 1962-2010. Br J Cancer 2019; 120:1153-1161. [PMID: 31105271 PMCID: PMC6738046 DOI: 10.1038/s41416-019-0469-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 04/16/2019] [Accepted: 04/18/2019] [Indexed: 12/27/2022] Open
Abstract
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.
Collapse
Affiliation(s)
- Kathryn J Bunch
- National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Old Road Campus, Oxford, OX3 7LF, UK.
| | - Gerald M Kendall
- Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Old Road Campus, Oxford, OX3 7LF, UK
| | - Charles A Stiller
- National Cancer Registration and Analysis Service, Public Health England, Chancellor Court, Oxford Business Park South, Oxford, OX4 2GX, UK
| | - Timothy J Vincent
- Formerly of Childhood Cancer Research Group, University of Oxford, Oxford, UK
| | - Michael F G Murphy
- Nuffield Department of Women's and Reproductive Health John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| |
Collapse
|
2
|
Maternal Exposure to Pesticides, Paternal Occupation in the Army/Police Force, and CYP2D6*4 Polymorphism in the Etiology of Childhood Acute Leukemia. J Pediatr Hematol Oncol 2018; 40:e207-e214. [PMID: 29432309 DOI: 10.1097/mph.0000000000001105] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Epidemiologic studies have suggested that parental occupations, pesticide use, environmental factors, and genetic polymorphism are involved in the etiology of childhood acute leukemia (CAL). In total, 116 cases of CAL and 162 controls were recruited and submitted to blood drawing to assess the presence of genetic polymorphisms. Parental occupations, pesticides exposure, and other potential determinants were investigated. Increased risk for CAL was associated with prenatal maternal use of insecticides/rodenticides (odds ratio [OR]=1.87; 95% confidence intervals [CI], 1.04-3.33), with subjects living <100 m from pesticide-treated fields (OR=3.21; 95% CI, 1.37-7.53) and with a paternal occupation as traffic warden/policeman (OR=4.02; 95% CI, 1.63-9.87). Associations were found between CAL and genetic polymorphism of CYP2D6*4 for homozygous alleles (mutant type/mutant type: OR=6.39; 95% CI, 1.17-34.66). In conclusion, despite the small sample size, maternal prenatal exposure to pesticides, paternal occupation as a traffic warden/police officer, and CYP2D6*4 polymorphism could play a role in the etiology of CAL.
Collapse
|
3
|
Case-control study of paternal occupation and childhood leukaemia in Great Britain, 1962-2006. Br J Cancer 2012; 107:1652-9. [PMID: 22968649 PMCID: PMC3493752 DOI: 10.1038/bjc.2012.359] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Background: Paternal occupational exposures have been proposed as a risk factor for childhood leukaemia. This study investigates possible associations between paternal occupational exposure and childhood leukaemia in Great Britain. Methods: The National Registry of Childhood Tumours provided all cases of childhood leukaemia born and diagnosed in Great Britain between 1962 and 2006. Controls were matched on sex, period of birth and birth registration subdistrict. Fathers’ occupations were assigned to 1 or more of 33 exposure groups. Social class was derived from father’s occupation at the time of the child’s birth. Results: A total of 16 764 cases of childhood leukaemia were ascertained. One exposure group, paternal social contact, was associated with total childhood leukaemia (odds ratio 1.14, 1.05–1.23); this association remained significant when adjusted for social class. The subtypes lymphoid leukaemia (LL) and acute myeloid leukaemia showed increased risk with paternal exposure to social contact before adjustment for social class. Risk of other leukaemias was significantly increased by exposure to electromagnetic fields, persisting after adjustment for social class. For total leukaemia, the risks for exposure to lead and exhaust fumes were significantly <1. Occupationally derived social class was associated with risk of LL, with the risk being increased in the higher social classes. Conclusion: Our results showed some support for a positive association between childhood leukaemia risk and paternal occupation involving social contact. Additionally, LL risk increased with higher paternal occupational social class.
Collapse
|
4
|
Abstract
This review considers recent studies regarding the role of environmental factors in the etiology of childhood leukemia and lymphoma. Potential environmental risk factors identified for childhood leukemia include exposure to magnetic fields of more than 0.4 micro Tessla, exposure to pesticides, solvents, benzene and other hydrocarbons, maternal alcohol consumption (but only for certain genotypes), contaminated drinking water, infections, and high birth weight. The finding of space-time clustering and seasonal variation also supports a role for infections. There is little evidence linking childhood leukemia with lifetime exposure to ionizing radiation although fetal exposures to X-rays are associated with increased risk. Breast-feeding, consumption of fresh fruit and vegetables and having allergies all appear to be protective. Burkitt lymphoma (BL) is confined to areas of the world where malaria is endemic, with the additional involvement of the Epstein-Barr virus (EBV) as a co-factor. Environmental risk factors suggested for other types of non-Hodgkin lymphoma (NHL) include exposure to ionizing radiation (both lifetime and antenatal), pesticides, and, in utero exposure to cigarette smoke, benzene and nitrogen dioxide (via the mother). Hodgkin lymphoma (HL) is especially associated with higher levels of socioeconomic deprivation, but breast-feeding seems to confer lower risk. This is consistent with an infection or immune-response mediated etiology for HL.
Collapse
Affiliation(s)
- Richard J Q McNally
- School of Clinical Medical Sciences, Child Health, University of Newcastle Upon Tyne, UK.
| | | |
Collapse
|
5
|
Ma X, Urayama K, Chang J, Wiemels JL, Buffler PA. Infection and pediatric acute lymphoblastic leukemia. Blood Cells Mol Dis 2008; 42:117-20. [PMID: 19064328 DOI: 10.1016/j.bcmd.2008.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 10/18/2008] [Indexed: 10/21/2022]
Abstract
In this review, we provide an overview of recent findings from the Northern California Childhood Leukemia Study (NCCLS) on factors related to the immune system including child's vaccination history and measures of child's exposure to infectious agents, namely daycare attendance, infection during infancy, and parental social contact in the work place. We also provide suggestions for the next stages of studies.
Collapse
Affiliation(s)
- Xiaomei Ma
- Department of Epidemiology and Public Health, Yale University School of Medicine, 60 College Street, New Haven, CT 06520-8034, USA.
| | | | | | | | | |
Collapse
|
6
|
Perez-Saldivar ML, Ortega-Alvarez MC, Fajardo-Gutierrez A, Bernaldez-Rios R, Del Campo-Martinez MDLA, Medina-Sanson A, Palomo-Colli MA, Paredes-Aguilera R, Martínez-Avalos A, Borja-Aburto VH, Rodriguez-Rivera MDJ, Vargas-Garcia VM, Zarco-Contreras J, Flores-Lujano J, Mejia-Arangure JM. Father's occupational exposure to carcinogenic agents and childhood acute leukemia: a new method to assess exposure (a case-control study). BMC Cancer 2008; 8:7. [PMID: 18194546 PMCID: PMC2245964 DOI: 10.1186/1471-2407-8-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Accepted: 01/14/2008] [Indexed: 11/10/2022] Open
Abstract
Background Medical research has not been able to establish whether a father's occupational exposures are associated with the development of acute leukemia (AL) in their offspring. The studies conducted have weaknesses that have generated a misclassification of such exposure. Occupations and exposures to substances associated with childhood cancer are not very frequently encountered in the general population; thus, the reported risks are both inconsistent and inaccurate. In this study, to assess exposure we used a new method, an exposure index, which took into consideration the industrial branch, specific position, use of protective equipment, substances at work, degree of contact with such substances, and time of exposure. This index allowed us to obtain a grade, which permitted the identification of individuals according to their level of exposure to known or potentially carcinogenic agents that are not necessarily specifically identified as risk factors for leukemia. The aim of this study was to determine the association between a father's occupational exposure to carcinogenic agents and the presence of AL in their offspring. Methods From 1999 to 2000, a case-control study was performed with 193 children who reside in Mexico City and had been diagnosed with AL. The initial sample-size calculation was 150 children per group, assessed with an expected odds ratio (OR) of three and a minimum exposure frequency of 15.8%. These children were matched by age, sex, and institution with 193 pediatric surgical patients at secondary-care hospitals. A questionnaire was used to determine each child's background and the characteristics of the father's occupation(s). In order to determine the level of exposure to carcinogenic agents, a previously validated exposure index (occupational exposure index, OEI) was used. The consistency and validity of the index were assessed by a questionnaire comparison, the sensory recognition of the work area, and an expert's opinion. Results The adjusted ORs and 95% confidence intervals (CI) were 1.69 (0.98, 2.92) during the preconception period; 1.98 (1.13, 3.45) during the index pregnancy; 2.11 (1.17, 3.78) during breastfeeding period; 2.17 (1.28, 3.66) after birth; and 2.06 (1.24, 3.42) for global exposure. Conclusion This is the first study in which an OEI was used to assess a father's occupational exposure to carcinogenic agents as a risk factor for the development of childhood AL in his offspring. From our results, we conclude that children whose fathers have been exposed to a high level of carcinogenic agents seem to have a greater risk of developing acute leukemia. However, confounding factors cannot be disregarded due to an incomplete control for confounding.
Collapse
Affiliation(s)
- Maria Luisa Perez-Saldivar
- Epidemiologia Clínica, Hospital de Pediatria, Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social (IMSS), DF, Mexico.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Chang JS, Metayer C, Fear NT, Reinier K, Yin X, Urayama K, Russo C, Jolly KW, Buffler PA. Parental social contact in the work place and the risk of childhood acute lymphoblastic leukaemia. Br J Cancer 2007; 97:1315-21. [PMID: 17923868 PMCID: PMC2360459 DOI: 10.1038/sj.bjc.6604024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
To study the possible relation between parental social contact through occupation, a marker for a child's risk of infection, and childhood acute lymphoblastic leukaemia (ALL), the parents of 294 children with ALL aged 0-14.9 years and 376 matched controls were interviewed about their jobs after their child's birth up to the age of 3 years. Job titles were assigned to a level of social contact, and an index of occupational social contact months was created using the level and the job duration. Positive interactions between this index and rural residence associated with an increased risk of childhood ALL and common ALL (c-ALL) were observed (interaction P-value=0.02 for both, using tertiles of contact months; interaction P-value=0.05 and 0.02 for ALL and c-ALL, respectively, using continuous contact months); such findings were not observed when job durations were ignored. Our data suggest that duration of parental occupation may be important when examining the association between parental social contact in the workplace and childhood leukaemia.
Collapse
Affiliation(s)
- J S Chang
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Abstract
OBJECTIVES Epidemiological studies have reported associations between childhood cancer and either parental or child exposure to pesticides. Reviews have been published in 1997, 1998 and 2006 where the evidence was found suggestive but not conclusive. The present review is an extended update of the latter one. METHODS The PubMed database was searched to identify published studies on this topic issued between 1998 and 2006. RESULTS Thirty-six new studies have been identified for this review. Some cohort studies and the majority of the case-control studies suggest an increased risk for the cancer types studied, associated with exposure to pesticides in at least one of a large variety of exposure categories. However, the evidence is conflicting with regard to cancer types as well as to causative factors across studies. The major shortcomings concern exposure assessment, where, e. g., "farming" is treated equal to "exposure to pesticides", disregarding other possible exposures, e.g., to biological or infectious agents, and hitherto unidentified lifestyle factors. Also, many exposure categories used, mainly in case-control studies, lack chemical or toxicological plausibility. In most studies exposures were categorized as "ever vs. never", with little regard of exposure intensity or duration. CONCLUSIONS The available literature does not allow firm conclusions with regard to pesticides and any type of childhood cancer. But even if the reported associations were true, exposure to pesticides could not explain the vast majority of childhood cancer cases. Investing in the acquisition and critical review of exposure information appears to be the crucial step for causal assessment in future research. However, focusing on the presence of pesticides, and not asking the question why they were used, might mask relevant associations to other causative agents.
Collapse
Affiliation(s)
- Michael Nasterlack
- Occupational Medicine and Health Protection Department, BASF AG, Ludwigshafen, Germany.
| |
Collapse
|
9
|
Pearce MS, Hammal DM, Dorak MT, McNally RJQ, Parker L. Paternal occupational exposure to electro-magnetic fields as a risk factor for cancer in children and young adults: a case-control study from the North of England. Pediatr Blood Cancer 2007; 49:280-6. [PMID: 16941646 DOI: 10.1002/pbc.21021] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Numerous studies have implied that paternal occupational exposures, in particular electromagnetic fields (EMF) and ionizing radiation, may be involved in the etiology of childhood cancers. We investigated whether an association exists between paternal occupations at birth involving such exposures and cancer risk in offspring, using data from the Northern Region Young Persons' Malignant Disease Registry (NRYPMDR). PROCEDURE Cases (n=4,723) were matched, on sex and year of birth, to controls from two independent sources: (i) all other patients from the NRYPMDR with a different cancer, (ii) 100 cancer-free individuals per case from the Cumbrian Births Database. An occupational exposure matrix was used to assign individuals to exposure groups. RESULTS There was an increased risk of leukemia among the offspring of men employed in occupations likely to be associated with EMF or radiation exposures (OR 1.31, 95% CI 1.02-1.69), particularly in males aged less than 6 years (OR 1.81, 95% 1.19-2.75). No significant association was seen in females. Increased risks were also seen for chondrosarcoma (OR 8.7, 95% CI 1.55-49.4) and renal carcinoma (OR 6.75, 95% CI 1.73-26.0). These associations were consistent between control groups and remained after adjustment for socio-economic status. CONCLUSIONS This large case-control study identified a significantly increased risk of leukemia among the offspring of men likely to have been occupationally exposed to EMF, with differing associations between males and females. Increased risks of chondrosarcoma and renal carcinoma were also seen, although based on smaller numbers. Further detailed investigations in this area are required to understand this association.
Collapse
Affiliation(s)
- Mark S Pearce
- Paediatric and Lifecourse Epidemiology Research Group, School of Clinical Medical Sciences (Child Health), University of Newcastle upon Tyne, UK.
| | | | | | | | | |
Collapse
|
10
|
Buka I, Koranteng S, Osornio Vargas AR. Trends in childhood cancer incidence: review of environmental linkages. Pediatr Clin North Am 2007; 54:177-203, x. [PMID: 17306690 DOI: 10.1016/j.pcl.2006.11.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cancer in children is rare and accounts for about 1% of all malignancies. In the developed world, however, it is the commonest cause of disease-related deaths in childhood, carrying with it a great economic and emotional cost. Cancers are assumed to be multivariate, multifactorial diseases that occur when a complex and prolonged process involving genetic and environmental factors interact in a multistage sequence. This article explores the available evidence for this process, primarily from the environmental linkages perspective but including some evidence of the genetic factors.
Collapse
Affiliation(s)
- Irena Buka
- Paediatric Environmental Health Specialty Unit, Misericordia Hospital, 3 West, 16940 - 87 Avenue, Edmonton, AB T5R 4H5, Canada.
| | | | | |
Collapse
|
11
|
Paltiel O, Laniado DE, Yanetz R, Deutsch L, Calderon-Margalit R, Harlap S, Friedlander Y. The Risk of Cancer following Hospitalization for Infection in Infancy: A Population-Based Cohort Study. Cancer Epidemiol Biomarkers Prev 2006; 15:1964-8. [PMID: 17035406 DOI: 10.1158/1055-9965.epi-06-0313] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The relation between infections in infancy and subsequent cancer risk in children and young adults is controversial. Our aim was to examine this association in the Jerusalem Perinatal Study, a population-based cohort comprising all offspring from western Jerusalem and surroundings born from 1964 to 1976. METHODS Identity numbers of non-malformed singletons with recorded data about hospital admission in the 1st year of life (n = 24,554) were linked to the Population and Cancer Registries. Person-year incidence rates were calculated for the exposed (admitted for infection) and nonexposed (not admitted for infection) groups from birth to date of cancer diagnosis, death, or December 31, 2004. We used Cox proportional hazards models to adjust for covariates associated with hospitalization. RESULTS The median follow-up was 36 years. Cancer developed in 283 individuals. Hospitalization for infection was not associated with overall cancer risk [risk ratio (RR), 0.88; 95% confidence interval (95% CI), 0.56-1.37]. The incidence rate for non-Hodgkin's lymphoma was higher in the exposed compared with the nonexposed group (RR, 3.46; 95% CI, 1.38-8.68), remaining unchanged after controlling for birth weight, gender, and maternal education. Leukemia risk was not significantly associated (RR, 0.44; 95% CI, 0.06-3.24) with hospitalization for infection. CONCLUSIONS Hospital admission in the 1st year of life due to infection is associated with an increased risk of non-Hodgkin's lymphoma. This is consistent with observations that mild immunodeficiencies predispose to lymphoma. Survival of infants with subtle immune defects, who may have previously succumbed to their infection, may contribute to the increased incidence of non-Hodgkin's lymphoma observed over the last 50 years.
Collapse
Affiliation(s)
- Ora Paltiel
- School of Public Health and Community Medicine, Hadassah-Hebrew University Hospital, Jerusalem, Israel.
| | | | | | | | | | | | | |
Collapse
|
12
|
Nasterlack M. Do pesticides cause childhood cancer? Int Arch Occup Environ Health 2006; 79:536-44. [PMID: 16463063 DOI: 10.1007/s00420-006-0086-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Accepted: 01/05/2006] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Epidemiological studies have reported associations between childhood cancer and either parental or child exposure to pesticides. Reviews have been published in 1997 and 1998, where the evidence was found suggestive but not conclusive. An update of the current state of knowledge is warranted. METHODS A literature search has been conducted to identify and evaluate new research results on this topic issued between 1998 and 2004. RESULTS Eighteen new studies have been identified for this review. Collectively, the studies suggest an increase in the risk of different cancer types associated with exposure to pesticides. However, the evidence is conflicting with regard to cancer types as well as to causative factors across studies. The major shortcomings concern exposure assessment, where, e.g., "farming" is treated equal to "exposure to pesticides," disregarding other possible exposures, e.g., to biological or infectious agents, and hitherto unidentified lifestyle factors. Also, many exposure questionnaires used in case-control studies are based on broad and sometimes implausible categories. In most studies exposures were categorized as "ever vs. never," with no regard for exposure intensity or duration. CONCLUSIONS The available literature does not allow firm conclusions with regard to pesticides and any type of childhood cancer. Investing in the acquisition and critical review of exposure information appears to be the crucial step for causal assessment in future research. However, focusing on the presence of pesticides, and not asking the question why they were used, might mask relevant associations to other causative agents.
Collapse
Affiliation(s)
- Michael Nasterlack
- Department of Occupational Medicine and Health Protection, BASF AG, 67056, Ludwigshafen, Germany.
| |
Collapse
|
13
|
Svec MA, Ward MH, Dosemeci M, Checkoway H, De Roos AJ. Risk of lymphatic or haematopoietic cancer mortality with occupational exposure to animals or the public. Occup Environ Med 2005; 62:726-35. [PMID: 16169919 PMCID: PMC1740863 DOI: 10.1136/oem.2005.021550] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Occupational exposure to animals or the public could result in exposure to infectious agents, which may play a role in the aetiology of lymphohaematopoietic (LH) cancers. AIMS To conduct a population based, case-control study of death certificate data from 1984 to 1998 in 24 US states in order to evaluate the risk of mortality from LH neoplasms associated with occupational exposure to animals or the public. METHODS Cases were selected as those with an underlying cause of death of non-Hodgkin's lymphoma (NHL, n = 72,589), Hodgkin's disease (HD, n = 5479), multiple myeloma (n = 35,857), or leukaemia (n = 68,598); 912 615 controls were randomly selected from all remaining deaths, frequency matched on age, sex, race, and geographic region. RESULTS Occupational exposure to animals was associated with modest increased risks of mortality from all four LH cancers; these associations varied by region. Occupational exposure to the public was associated with only negligible increased risk with LH cancer outcomes. Occupations involving animal exposure were predominantly agricultural, and the risks associated with employment in the livestock industry exceeded the corresponding risks associated with the crop industry for all outcomes except HD. CONCLUSIONS Increased risks of NHL, HD, multiple myeloma, and leukaemia were associated with occupations that involved animal exposure. Regional differences in risk imply that the risks may be associated with exposure to specific livestock or farming practices. However, these associations may be confounded by other farming related exposures, such as pesticides. Because the use of death certificates to classify occupation may result in misclassification during aetiologically relevant time periods, these hypotheses should be further explored in studies with detailed information on lifetime occupation.
Collapse
Affiliation(s)
- M A Svec
- Department of Epidemiology, University of Washington, Seattle, Washington, USA
| | | | | | | | | |
Collapse
|
14
|
Fear NT, Simpson J, Roman E. Childhood Cancer and Social Contact: the Role of Paternal Occupation (United Kingdom)*. Cancer Causes Control 2005; 16:1091-7. [PMID: 16184475 DOI: 10.1007/s10552-005-0402-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Accepted: 06/02/2005] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate the relationship between childhood cancer (particularly leukaemia) and paternal occupational social contact (a proxy for potential exposure to infections) using the UK Childhood Cancer Study. METHODS Using a national population-based case-control study, self-reported occupational data from fathers of 3596 children diagnosed with cancer between 1991 and 1996 under 15 years of age (cases) and fathers of 7011 children without cancer (controls) were analysed. Associations were assessed using odds ratios (OR) calculated by time of exposure (birth, diagnosis), diagnostic group (all cancers, leukaemia, acute lymphoblastic leukaemia (ALL), central nervous system tumours, other cancers), level of occupational social contact (high, medium, low), urban-rural status at diagnosis and occupational title. RESULTS From 371 occupations, 75 (20%) were classified as having high levels of occupational social contact, 31 (8%) as medium and the remaining 265 (71%) as low. No associations were apparent for fathers' occupational social contact overall, for any time period or diagnostic group. OR for leukaemia and high levels of paternal occupational social contact at birth and diagnosis being 1.02 (95% confidence interval (CI) = 0.88-1.18) and 0.91 (95% CI = 0.79-1.06), respectively. Analyses by urban-rural status at diagnosis and by occupational title revealed no notable associations. CONCLUSIONS The analyses of paternal occupational histories do not support the suggested association between high levels of paternal occupational social contact and an increased risk of childhood leukaemia. However, the role of participation bias should not be discounted.
Collapse
Affiliation(s)
- Nicola T Fear
- Academic Centre for Defence Mental Health, Institute of Psychiatry, King's College London, Weston Education Centre, Cutcombe Road, London SE5 9RJ , UK.
| | | | | |
Collapse
|
15
|
Abstract
There are three current hypotheses concerning infectious mechanisms in the aetiology of childhood leukaemia: exposure in utero or around the time of birth, delayed exposure beyond the first year of life to common infections and unusual population mixing. No specific virus has been definitively linked with childhood leukaemia and there is no evidence to date of viral genomic inclusions within leukaemic cells. The case-control and cohort studies have revealed equivocal results. Maternal infection during pregnancy has been linked with increased risk whilst breast feeding and day care attendance in the first year of life appear to be protective. There is inconclusive evidence from studies on early childhood infectious exposures, vaccination and social mixing. Some supportive evidence for an infectious aetiology is provided by the findings of space-time clustering and seasonal variation. Spatial clustering suggests that higher incidence is confined to specific areas with increased levels of population mixing, particularly in previously isolated populations. Ecological studies have also shown excess incidence with higher population mixing. The marked childhood peak in resource-rich countries and an increased incidence of the childhood peak in acute lymphoblastic leukaemia (ALL) (occurring at ages 2-6 years predominantly with precursor B-cell ALL) is supportive of the concept that reduced early infection may play a role. Genetically determined individual response to infection may be critical in the proliferation of preleukaemic clones as evidenced by the human leucocyte antigen class II polymorphic variant association with precursor B-cell and T-cell ALL.
Collapse
Affiliation(s)
- Richard J Q McNally
- Cancer Research UK Paediatric and Familial Cancer Research Group, Central Manchester and Manchester Children's University Hospitals NHS Trust, Manchester, UK.
| | | |
Collapse
|