Risk Of Childhood Leukemia Research Articles

Mortality and Cancer Incidence in Carriers of Balanced Robertsonian Translocations: A National Cohort Study

A balanced robertsonian translocation (rob) results from fusion of 2 acrocentric chromosomes. Carriers are phenotypically normal and are often diagnosed because of recurrent miscarriages, infertility, or aneuploid offspring. Mortality and site-specific cancer risks in carriers have not been prospectively investigated. We followed 1,987 carriers diagnosed in Great Britain for deaths and cancer risk, over an average of 24.1 years. Standardized mortality and incidence ratios were calculated comparing the number of observed events against population rates. Overall mortality was higher for carriers diagnosed before age 15 years (standardized mortality ratio (SMR) = 2.00, 95% confidence interval (CI): 1.09, 3.35), similar for those diagnosed aged 15–44 years (SMR = 1.06, 95% CI: 0.86–1.28), and lower for those diagnosed aged 45–84 years (SMR = 0.81, 95% CI: 0.68, 0.95). Cancer incidence was higher for non-Hodgkin lymphoma (standardized incidence ratio (SIR) = 1.90, 95% CI: 1.01, 3.24) and childhood leukemia (SIR = 14.5, 95% CI: 1.75, 52.2), the latter particularly in rob(15;21) carriers (SIR = 447.8, 95% CI: 11.3, 2,495). Rob(13;14) carriers had a higher breast cancer risk (SIR = 1.58, 95% CI: 1.12, 2.15). Mortality risks relative to the population in diagnosed carriers depend on age at cytogenetic diagnosis, possibly reflecting age-specific cytogenetic referral reasons. Carriers might be at greater risk of childhood leukemia and non-Hodgkin lymphoma and those diagnosed with rob(13;14) of breast cancer.

Maternal exposure to gasoline and exhaust increases the risk of childhood leukaemia in offspring \u2013 a prospective study in the Norwegian Mother and Child Cohort Study

BackgroundIn the prospective population-based Norwegian Mother and Child Cohort Study (MoBa), comprising 113 754 offspring, we investigated the association between parental exposure to “gasoline or exhaust”, as a proxy for benzene exposure, and childhood leukaemia.MethodsAround gestational week 17, mothers and fathers responded to a questionnaire on exposure to various agents during the last 6 months and 6 months pre-conception, respectively. Benzene exposure was assessed through self-reported exposure to “gasoline or exhaust”. Cases of childhood leukaemia (n = 70) were identified through linkage with the Cancer Registry of Norway. Risk was estimated by hazard ratios (HRs) with 95% confidence intervals (95%CI), comparing offspring from exposed and unexposed parents using a Cox regression model.ResultsMaternal exposure to "gasoline or exhaust" was associated with an increased risk of childhood leukaemia (HR = 2.59; 95%CI: 1.03, 6.48) and acute lymphatic leukaemia (HR = 2.71; 95%CI: 0.97, 7.58). There was an increasing risk for higher exposure (p value for trend = 0.032 and 0.027). The association did not change after adjustment for maternal smoking.ConclusionIn spite of rather few cases, the findings in this prospective study, with the exposure metric defined a priori, support previous observations relating maternal exposure to benzene from gasoline and other petroleum-derived sources and the subsequent development of childhood leukaemia in the offspring.

Household exposure to pesticides and risk of leukemia in children and adolescents: Updated systematic review and meta-analysis.

The role that pesticides in the domestic environment might play in the etiology of childhood leukemia remains a subject of controversy. Recent studies often reached inconsistent conclusions. To update our earlier systematic review on the association between residential/household/domestic exposure to pesticides and childhood leukemia, and to explore potential sources of heterogeneity not previously assessed. A systematic search of studies published in English between January 2009 and June 2018 was conducted in MEDLINE, and a "snowball searching" was performed from the reference list of identified publications and from Web of Science citations. Risk estimates were extracted from 15 case-control studies published between 1987 and 2018. The quality of the publications was assessed by using a modified version of the Downs and Black (1998) checklist. A random-effect meta-analysis model was used to calculate summary odds ratios (SOR) and separate analyses were conducted for acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), unspecified AL/leukemia and any leukemia types. Stratification by critical exposure period, exposure location, pesticide biocide category, child age at diagnosis, study quality, specific exposures, type of pest treated, and geographic location were performed. A statistically significant association between residential pesticide exposure and childhood leukemia was observed by combining all studies (SOR: 1.57; 95% CI: 1.27-1.95) without evidence of publication bias. Statistically significant increased risks were observed for all types of leukemia, and specifically for exposure during pregnancy, indoor exposure, prenatal exposure to insecticides and whatever the age at diagnosis. Statistical significance was also reached for high quality studies, pet treatments, professional pest control treatment and use of insect repellants, mosquito treatment and for studies from USA/Canada or International. The highest increased risks were observed for AML among children aged 2 years or less, as well as for unspecified leukemia type observed after prenatal indoor exposure. A positive association between domestic pesticide exposure and childhood leukemia is confirmed. Although the literature provides moderate to low-quality of evidence, these new results further justify the need of limiting the use of household pesticides during pregnancy and childhood.

Maternal Residential Pesticide Use and Risk of Childhood Leukemia in Costa Rica

Evidence suggests that early-life exposure to pesticides inside the home may be associated with childhood leukemia, however data from Latin American countries are limited. We examined whether self-reported maternal residential pesticide use and nearby pesticide applications-before and after child's birth-were associated with acute lymphoblastic leukemia (ALL) in the Costa Rican Childhood Leukemia Study (CRCLS), a population-based case-control study (2001-2003). Cases (n = 251 ALL) were diagnosed between 1995 and 2000 (age <15 years at diagnosis) and were identified through the Costa Rican Cancer Registry and National Children's Hospital. Population controls (n = 577) were drawn from the National Birth Registry. We fitted unconditional logistic regression models adjusted for child sex, birth year, and socioeconomic status to estimate the exposure-outcome associations and also stratified by child sex. We observed that self-reported maternal insecticide use inside the home in the year before pregnancy, during pregnancy, and while breastfeeding was associated with increased odds of ALL among boys [adjusted Odds Ratio (aOR) = 1.63 (95% confidence interval [95% CI]: 1.05-2.53), 1.75 (1.13-2.73), and 1.75 (1.12-2.73), respectively. We also found evidence of exposure-response relationships between more frequent maternal insecticide use inside the home and increased odds of ALL among boys and girls combined. Maternal report of pesticide applications on farms or companies near the home during pregnancy and at any time period were also associated with ALL. Our study in Costa Rica highlights the need for education to minimize pesticide exposures inside and around the home, particularly during pregnancy and breastfeeding.

Early-Life Infections, Immune Dysregulation, and Childhood Acute Lymphocytic Leukemia in Costa Rica

Introduction: Despite the high incidence of leukemia in Hispanic children, few studies have examined the role of early immune stimulation in the etiology of leukemia in this high-risk population. Methods: We used data from a population-based retrospective case-control study conducted in Costa Rica (2001-2003) to examine the role of early-life infections and immune dysregulation on leukemia incidence among Hispanic children. Cases of ALL (n&amp;#61;239) were diagnosed in 1995-2000 (age &amp;lt;15 years at diagnosis) and were identified through the National Cancer Registry and National Children&amp;#8217;s Hospital. Population controls (n&amp;#61;579) were frequency-matched to cases by birth year and drawn from the National Birth Registry. Surrogate measures of early immune stimulation were collected through home interviews. Unconditional logistic regression models were adjusted for birth year, sex, and socioeconomic status. Results: Daycare attendance, contact with any pet or farm animal, and a complete vaccination scheme were inversely associated with odds of ALL (OR&amp;#61;0.67, 95% CI: 0.47-0.95; OR&amp;#61;0.39, 95% CI: 0.26-0.59; OR&amp;#61;0.35, 95% CI: 0.18-0.67; respectively). In contrast, experiencing a fever longer than one week (censored in the year prior to diagnosis) was positively associated with ALL (OR&amp;#61;2.53, 95% CI: 1.66-3.85). Breastfeeding, birth order, primary infections, and hospitalizations were not significantly associated with risk of childhood leukemia. Conclusion: Our findings are consistent with the epidemiology of childhood leukemia in non-Hispanic populations and provide additional support for Greaves hypothesis that exposure to infectious agents in early childhood is a protective factor. The observation that having a fever longer than a week increases risk supports an emerging theory that an abnormally strong immune response to infection increases susceptibility to leukemia.

Residential Proximity to Agricultural Herbicides during Pregnancy and Childhood Leukemia in the Danish National Birth Cohort

BackgroundThe majority (61%) of Denmark&amp;#8217;s land cover is agricultural. Cereals and grains are the major crops, and almost all acres of these crops are treated with herbicides. Based mostly on case-control studies, parental exposure to pesticides during pregnancy has been associated with increased risk of childhood cancer.MethodsThe Danish National Birth Cohort (DNBC) enrolled over 100,000 pregnant women 1996-2003. For childhood leukemias (diagnosed &amp;lt;15 years) through 2014 and 10% of the cohort (N&amp;#61;9,362, excluding non-singleton births and children with Down Syndrome), we linked addresses during the pregnancy to crop maps and crop-specific pesticide sales data to estimate the amount (g) of herbicides applied at distances within 100, 250, 500, 1000m of homes. We used Cox proportional hazard models to estimate hazard ratios (HR) and 95% confidence intervals (95%CI) for 18 herbicides with the highest use.ResultsThere were 191 children diagnosed with childhood cancer, including 61 leukemia cases. Some herbicides were used on the same crops or applied as mixtures, resulting in high correlations (Spearman&amp;#8217;s rho: 0.46-1.00). For the highest tertile (vs. no pesticide use) within 500m from the home, we found increased risk of leukemia for MCPA&amp;#43;methabenzthiazuron (HR: 2.08, 95%CI: 1.06-4.07), dichlorprop-p/mecoprop-p (HR: 2.10, 95%CI: 1.07-4.11), benzonitrile herbicides (HR: 2.21, 95%CI: 1.14-4.29), thifensulfuron-methyl (HR: 2.09, 95%CI: 1.07,4.09), bentazone (HR: 2.20, 95%CI: 1.13-4.27), and phenmedipham (HR: 2.16, 95%CI: 1.10-4.23), without significant trends. Risk patterns at other distances from the home were similar but attenuated. There was no association with leukemia and use of glyphosate, clopyralid, 2,4-D, and 6 other herbicides.ConclusionsThis is the first prospective study to evaluate residential proximity to pesticide applications and childhood cancer, and provides additional evidence that pesticide exposures during pregnancy may increase childhood leukemia risk.

Childhood leukaemia risk and residential proximity to busy roads

BackgroundCurrent evidence suggests that childhood leukaemia can be associated with residential traffic exposure; nevertheless, more results are needed to support this conclusion. ObjectivesTo ascertain the possible effects of residential proximity to road traffic on childhood leukaemia, taking into account traffic density, road proximity and the type of leukaemia (acute lymphoid leukaemia or acute myeloid leukaemia). MethodsWe conducted a population-based case-control study of childhood leukaemia in Spain, covering the period 1990–2011. It included 1061 incidence cases gathered from the Spanish National Childhood Cancer Registry and those Autonomous Regions with 100% coverage, and 6447 controls, individually matched by year of birth, sex and autonomous region of residence. Distances were computed from the respective participant's residential locations to the different types of roads and four different buffers. Using logistic regression, odds ratios (ORs) and 95% confidence intervals (95%CIs), were calculated for four different categories of distance to roads. ResultsCases of childhood leukaemia had more than three-fold increased odds of living at <50 m of the busiest motorways compared to controls (OR = 2.90; 95%CI = 1.30–6.49). The estimates for acute lymphoid leukaemia (ALL) were slightly higher (OR = 2.95; 95%CI = 1.22–7.14), while estimates for cases with the same address at birth and at diagnosis were lower (OR = 2.40; 95%CI = 0.70–8.30). ConclusionsOur study agrees with the literature and furnishes some evidence that living near a busy motorway could be a risk factor for childhood leukaemia.

Maternal use of hormonal contraception and risk of childhood leukaemia: a nationwide, population-based cohort study.

Maternal hormonal contraception has been suspected of being linked to an increased risk of childhood cancer. The aim of this study was to assess the association between maternal use of hormonal contraception and diagnosis of leukaemia in their children. In this cohort study, we followed a nationwide cohort of 1 185 157 liveborn children between 1996 and 2014 listed in the Danish Medical Birth Registry and identified those diagnosed with leukaemia in the Danish Cancer Registry. Redeemed prescriptions from the Danish National Prescription Registry provided information about maternal hormonal contraceptive use, categorised as: no use (never used contraception before birth; reference category), previous use (>3 months before start of pregnancy), and recent use (≤3 months before and during pregnancy). We also calculated risk estimates separately for maternal hormonal contraceptive use during pregnancy. The primary outcome of interest was a diagnosis of any leukaemia in the children. Secondary outcomes were diagnoses of lymphoid leukaemia and non-lymphoid leukaemia. We used Cox proportional hazards models to estimate hazard ratios (HRs) with 95% CIs for risk of leukaemia in children. The Data Protection Agency registration number for this study is 2017-41-5221. Between Jan 1, 1996, and Dec 31, 2014, the 1 185 157 liveborn children accumulated 11 114 290 person-years of follow-up (median 9·3 years, IQR 4·6-14·2), during which 606 children were diagnosed with leukaemia (465 with lymphoid leukaemia and 141 with non-lymphoid leukaemia). Children born to women with recent use of any type of hormonal contraception were at higher risk for any leukaemia than children of women who never used contraception (HR 1·46, 95% CI 1·09-1·96; p=0·011); and for exposure during pregancy the risk was 1·78 (0·95-3·31; p=0·070). No association was found between timing of use and risk for lymphoid leukaemia (HR 1·23, 95% CI 0·97-1·57, p=0·089, for previous use and 1·27, 0·90-1·80, p=0·167, for recent use); however, the HRs for non-lymphoid leukaemia were 2·17 (1·22-3·87; p=0·008) for recent use and 3·87 (1·48-10·15; p=0·006) for use during pregnancy. Hormonal contraception use close to or during pregnancy might have resulted in one additional case of leukaemia per about 50 000 exposed children, or 25 cases during the 9-year study period. Our findings suggest the maternal hormonal use affects non-lymphoid leukaemia development in children. Since almost no risk factors have been established for childhood leukaemia, these findings suggest an important direction for future research into its causes and prevention. The Danish Cancer Research Foundation, the Arvid Nilssons Foundation, the Gangsted Foundation, the Harboe Foundation, and the Johannes Clemmesens Foundation.

Characterization of Children’s Exposure to Extremely Low Frequency Magnetic Fields by Stochastic Modeling

In this study, children’s exposure to extremely low frequency magnetic fields (ELF-MF, 40–800 Hz) is investigated. The interest in this thematic has grown due to a possible correlation between the increased risk of childhood leukemia and a daily average exposure above 0.4 µT, although the causal relationship is still uncertain. The aim of this paper was to present a new method of characterizing the children’s exposure to ELF-MF starting from personal measurements using a stochastic approach based on segmentation (and to apply it to the personal measurements themselves) of two previous projects: the ARIMMORA project and the EXPERS project. The stochastic model consisted in (i) splitting the 24 h recordings into stationary events and (ii) characterizing each event with four parameters that are easily interpretable: the duration of the event, the mean value, the dispersion of the magnetic field over the event, and a final parameter characterizing the variation speed. Afterward, the data from the two databases were divided in subgroups based on a characteristic (i.e., children’s age, number of inhabitants in the area, etc.). For every subgroup, the kernel density estimation (KDE) of each parameter was calculated and the p-value histogram of the parameters together was obtained, in order to compare the subgroups and to extract information about the children’s exposure. In conclusion, this new stochastic approach allows for the identification of the parameters that most affect the level of children’s exposure.

Protective effect of breastfeeding against childhood leukemia in Zhejiang Province, P. R. China: a retrospective case-control study

ABSTRACTObjectives: Our research investigated the relationship between childhood leukemia and breastfeeding in the P. R. of China.Methods: We conducted a retrospective case-control study from March 2008 to April 2017 at the Children’s Hospital of Zhejiang University, Zhejiang province, P. R. of China, which reviewed 958 children who had been diagnosed with leukemia in case group and 785 healthy children in control group. Data were obtained from medical records, and if the medical records were incomplete, we called mothers of children by phone to complete the data.Results: Breastfeeding reduces the risk of childhood leukemia; the effect is greater, if feeding continued for 7–9 months (p = 0.002). In addition, we suggest that some factors such as maternal age, smoking during pregnancy, abortion history, genetic factors, parents use of hair dye, and the history of using birth control pills before pregnancy can increase the risk of childhood leukemia.Conclusions: This study indicates that promoting breastfeeding for 7–9 months may help lower the childhood leukemia incidence. Our study firstly demonstrates that breastfeeding has protective effects against childhood leukemia in the P. R. of China.Abbreviations: ALL: Acute lymphocytic leukemia; AML: Acute myeloid leukemia

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.

Radiation exposure from computerized tomography and risk of childhood leukemia: Finnish register-based case-control study of childhood leukemia (FRECCLE).

The only well-established risk factors for childhood leukemia are high-dose ionizing radiation and Down syndrome. Computerized tomography is a common source of low-dose radiation. In this study, we examined the magnitude of the risk of childhood leukemia after pediatric computed tomography examinations. We evaluated the association of computed tomography scans with risk of childhood leukemia in a nationwide register-based case-control study. Cases (n=1,093) were identified from the population-based Finnish Cancer Registry and three controls, matched by gender and age, were randomly selected for each case from the Population Registry. Information was also obtained on birth weight, maternal smoking, parental socioeconomic status and background gamma radiation. Data on computed tomography scans were collected from the ten largest hospitals in Finland, covering approximately 87% of all pediatric computed tomography scans. Red bone marrow doses were estimated with NCICT dose calculation software. The data were analyzed using exact conditional logistic regression analysis. A total of 15 cases (1.4%) and ten controls (0.3%) had undergone one or more computed tomography scans, excluding a 2-year latency period. For one or more computed tomography scans, we observed an odds ratio of 2.82 (95% confidence interval: 1.05 – 7.56). Cumulative red bone marrow dose from computed tomography scans showed an excess odds ratio of 0.13 (95% confidence interval: 0.02 – 0.26) per mGy. Our results are consistent with the notion that even low doses of ionizing radiation observably increase the risk of childhood leukemia. However, the observed risk estimates are somewhat higher than those in earlier studies, probably due to random error, although unknown predisposing factors cannot be ruled out.

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

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

Maternal residential pesticide use and risk of childhood leukemia in Costa Rica.

Evidence suggests that early‐life exposure to pesticides inside the home may be associated with childhood leukemia, however data from Latin American countries are limited. We examined whether self‐reported maternal residential pesticide use and nearby pesticide applications–before and after child's birth–were associated with acute lymphoblastic leukemia (ALL) in the Costa Rican Childhood Leukemia Study (CRCLS), a population‐based case‐control study (2001‐2003). Cases (n = 251 ALL) were diagnosed between 1995 and 2000 (age <15 years at diagnosis) and were identified through the Costa Rican Cancer Registry and National Children's Hospital. Population controls (n = 577) were drawn from the National Birth Registry. We fitted unconditional logistic regression models adjusted for child sex, birth year, and socioeconomic status to estimate the exposure‐outcome associations and also stratified by child sex. We observed that self‐reported maternal insecticide use inside the home in the year before pregnancy, during pregnancy, and while breastfeeding was associated with increased odds of ALL among boys [adjusted Odds Ratio (aOR) = 1.63 (95% confidence interval [95% CI]: 1.05–2.53), 1.75 (1.13–2.73), and 1.75 (1.12–2.73), respectively. We also found evidence of exposure‐response relationships between more frequent maternal insecticide use inside the home and increased odds of ALL among boys and girls combined. Maternal report of pesticide applications on farms or companies near the home during pregnancy and at any time period were also associated with ALL. Our study in Costa Rica highlights the need for education to minimize pesticide exposures inside and around the home, particularly during pregnancy and breastfeeding.

A proposed explanation for thunderstorm asthma and leukemia risk near high-voltage power lines: a supported hypothesis

ABSTRACTThunderstorm asthma and increased childhood leukemia risk near high-voltage power lines (HVPL) are occurrences whose mechanism of effect is not fully understood.This paper proposes and discusses a key similarity: both thunderstorms and HVPL generate a high enough electrical field in the environment to ionize nearby air and air-borne particles.I argue that the repeatedly demonstrated acute asthma response to pollen-laden air during thunderstorms is largely due to ionization of air-borne allergens, which adhere more readily and in greater quantity in the lungs than non-ionized particles. If these bind to mucous or phagocytic cells, it would enhance immune response. A rapid temperature drop and high ozone also seem to be drivers of thunderstorm asthma.This causal nexus provides strong support for the parallel situation of prolonged exposure to ionized particles near HVPL and an increased rate of childhood leukemia. Here, it is proposed that upwind carcinogens are ionized when passing HVPL and then residential and business areas. Published evidence for most steps are presented, but have not previously been published as a coherent whole, nor has it been suggested that the inhaled ionized micro-particle explanation for acute asthma may also explain development of childhood leukemia over time.The demonstrated series of events leading to increased deposition and retention of ionized particles in airways provides support for explaining both adverse health outcomes: acute thunderstorm asthma and increased risk of childhood leukemia near HVPL. Further support for this explanation of both outcomes is provided by effects of on-going proximity to highways.

Системный анализ влияния солнечной радиации и дыма лесных пожаров на риск развития лейкоза у детей

Системный анализ влияния солнечной радиации и дыма лесных пожаров на риск развития лейкоза у детей

Parental Occupational Exposures and Risk of Childhood Acute Leukemia.

Introduction:Acute leukemia, accounting for 20% of all cancers diagnosed in individuals younger than 19 years old, is the most prevalent childhood malignancy. Among environmental risk factors, parental occupational exposures have attracted scientific interest as potential predisposing factors for childhood leukemia. The role of parental occupational exposure to social contacts, harmful chemicals, electromagnetic fields and ionizing radiation has been investigated with conflicting and inconsistent results.Aim:A case-control study aiming to assess the association between parental occupational exposures to social contacts, chemicals and electromagnetic fields and the risk of offspring acute leukemia.Material and Methods:108 children with acute leukemia and equal number of matched controls were included. Data on parental occupations before conception, during pregnancy, during breastfeeding and after birth, and on potential risk factors was recorded. Associations between parental exposure and risk of childhood leukemia were estimated.Results:Parental occupational exposure during the four periods of exposure was not associated with childhood leukemia. High birth weight and family history of cancer were associated with the development of childhood acute leukemia. A weak association of maternal medication use during pregnancy and leukemia risk emerged.Conclusions:Since the causative factors of childhood leukemia remain unknown, further investigation is mandatory for the reduction of disease burden.

Case-Control Study on Occupational Exposure to Extremely Low-Frequency Electromagnetic Fields and the Association with Meningioma.

Objective Exposure to extremely low-frequency electromagnetic fields (ELF-EMF) was in 2002 classified as a possible human carcinogen, Group 2B, by the International Agency for Research on Cancer at WHO based on an increased risk for childhood leukemia. In case-control studies on brain tumors during 1997–2003 and 2007–2009 we assessed lifetime occupations in addition to exposure to different agents. The INTEROCC ELF-EMF Job-Exposure Matrix was used for associating occupations with ELF-EMF exposure (μT) with meningioma. Cumulative exposure (μT-years), average exposure (μT), and maximum exposed job (μT) were calculated. Results No increased risk for meningioma was found in any category. For cumulative exposure in the highest exposure category 8.52+ μT years odds ratio (OR) = 0.9, 95% confidence interval (CI) = 0.7–1.2, and p linear trend = 0.45 were calculated. No statistically significant risks were found in different time windows. Conclusion In conclusion occupational ELF-EMF was not associated with an increased risk for meningioma.

Early vaccination protects against childhood leukemia: A systematic review and meta-analysis

Leukemia is the most commonly diagnosed childhood cancer, although its etiology is still largely unknown. Growing evidence supports a role for infection in the etiology of acute lymphocytic leukemia (ALL), and the involvement of the immune system suggests that vaccination may also play a role. However, the findings presented in the published literature are inconsistent. Therefore, we conducted a PRISMA systematic review and meta-analysis. 14 studies were identified and meta-analyzed. Vaccinations studied comprised Bacillus Calmette-Guérin (BCG) vaccine, Triple vaccine, Hepatitis B vaccine (HBV), Polio, Measles, Rubella, Mumps, trivalent MMR vaccine and Haemophilus influenza type B (HiB) vaccine. We observed a protective association between any vaccination in the first year of life and risk of childhood leukemia (summary odds ratio (OR) 0.58 [95% confidence interval (CI) 0.36–0.91]). When individual vaccines were analysed, some evidence of an association was seen only for BCG (summary OR 0.73 [95% CI 0.50–1.08]). In conclusion, early vaccination appears to be associated with a reduced risk of childhood leukemia. This finding may be underpinned by the association observed for BCG. Given the relatively imprecise nature of the results of this meta-analysis, our findings should be interpreted cautiously and replicated in future studies.

Gestational age and childhood leukemia: A meta-analysis of epidemiologic studies

ABSTRACTObjective: An increasing amount of evidence shows that childhood leukemia is initiated in utero. Birth characteristics initiated in utero, such as gestational age, may play a role in leukemogenesis. The purpose of our meta-analysis is to explore the association between gestational age and childhood leukemia.Methods: Relevant studies up to 21 April 2017 were collected by searching PubMed and EMBASE databases. Subgroup analysis, sensitivity analysis and publication bias assessment were conducted.Results: A total of 13 studies were included. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) for preterm birth and postterm birth were 1.06 (0.98, 1.13) and 1.01 (0.90, 1.13) for childhood leukemia, 1.04 (0.97, 1.11) and 1.03 (0.95, 1.12) for acute lymphocytic leukemia (ALL), 1.20 (1.00, 1.44) and 1.20 (1.00, 1.43) for acute myeloid leukemia (AML), compared with full-term birth. Study type and study region were the reasons behind the heterogeneity. In subgroup analyses, the summary ORs with 95% CI for childhood leukemia and ALL were 1.23 (1.07, 1.41) and 1.21 (1.06, 1.39) for postterm birth in cohort studies. No significant changes in sensitivity analyses and no publication bias were observed in our analysis.Conclusion: Our results suggest that both preterm and postterm infants have an elevated risk of developing AML. In addition, postterm birth increased the risk of childhood leukemia and ALL in cohort studies. However, more studies are warranted to validate these results and explore the biologic mechanisms underlying these relationships.