Parental smoking and childhood leukemia

Benzene exposure and pediatric leukemia: From molecular clues to epidemiological insights

According to the International Agency for Research on Cancer, leukemia ranks 14th in incidence and 11th in mortality and has a 5-year prevalence of approximately 1300,000 cases. Acute lymphoblastic leukemia is the most common hematopoietic syndrome in children during the first 5 years of life and represents approximately 75 % of all neoplasms among the pediatric population. The development of leukemia is strongly governed by DNA alterations that accelerate the growth of bone marrow cells. Currently, the most examined factor in pediatric leukemia is exposure to multiple compounds, such as hydrocarbons. Benzene, an aromatic hydrocarbon, can cause health challenges and is categorized as a carcinogen. Benzene toxicity has been widely associated with occupational exposure. Importantly, studies are underway to generate evidence that can provide clues regarding the risk of environmental benzene exposure and hematological problems in children. In this review, we summarize the existing evidence regarding the effects of benzene on pediatric leukemia, the associations between the effect of benzene on carcinogenesis, and the presence of certain molecular signatures in benzene-associated pediatric leukemia. Although there is sufficient evidence regarding the effects of benzene on carcinogenesis and leukemia, epidemiological research has primarily focused on occupational risk. Moreover, most benzene-induced molecular and cytogenetic alterations have been widely described in adults but not in the pediatric population. Thus, epidemiological efforts are crucial in the pediatric population in terms of epidemiological, clinical, and biomedical research.

Exploring knowledge of parents and caregivers on cancer symptoms in children: an observational study regarding the need for educational tools and health promotion in low- and middle-income countries

Background

Although most cases of childhood cancer are unlikely to be prevented, by today’s standards, most children with cancer can now be cured. However, disparities about survival exist among countries; in Mexico, the overall survival is 49.6%, with 70% of childhood cancers diagnosed at advanced stages. Therefore, parents and caregivers must have optimal knowledge of the early signs and symptoms of childhood malignancies as they are largely non-specific. This study was designed to explore the current knowledge of childhood cancer among parents and caregivers in Mexico and identify the need for education and health promotion in low- and middle-income countries.

Methods

An online survey of 112 parents and caregivers was performed to assess their knowledge of childhood cancer, focusing on the signs and symptoms and early diagnostic strategies.

Results

Sixty-nine (61.6%) mothers, 23 (20.5%) fathers, 17 (15.2%) familiar caregivers, and 3 (2.7%) non-familiar caregivers responded. Forty-six (41.1%) respondents said that they knew a child diagnosed with cancer, 92.9% mentioned leukemia as the most common type of cancer among children, the most highly ranked option when asked which sign/symptom they considered as a warning for suspicion was growth/lump in any part of the body, 97.3% considered that an early diagnosis is related to a higher cure rate, and 92.9% expressed the desire to receive reliable information about childhood cancer.

Conclusions

Although parents and caregivers have some knowledge of childhood cancer, there are concepts that should be reinforced to improve their understanding of this group of diseases, as they are the frontline for children to seek medical attention. In the future, the use of tools that help educate more caregivers will strengthen knowledge and contribution regarding this issue and promote the generation of public policies that support the early diagnosis of childhood cancer.

Should we be measuring DNA damage in human spermatozoa? New light on an old question

Assessments of sperm DNA damage are controversial because of perceived uncertainties over the relationship with pregnancy and the limited range of therapies available should positive results be returned. In this article, we highlight recent data supporting a chain of associations between oxidative stress in the male germ line, DNA damage in spermatozoa, defective DNA repair in the oocyte, the mutational load carried by the resulting embryo and the long-term health trajectory of the offspring. Any condition capable of generating oxidative damage in spermatozoa (age, obesity, smoking, prolonged abstinence, varicocele, chemical exposures, radiation etc.) is capable of influencing offspring health in this manner, creating a range of pathologies in the progeny including neuropsychiatric disorders and cancer. If sperm DNA damage is detected, there are several therapeutic interventions that can be introduced to improve DNA quality prior to the use of these cells in ART. We therefore argue that infertility specialists should be engaged in the diagnosis and remediation of sperm DNA damage as a matter of best practice, in order to minimize the risk of adverse health outcomes in children conceived using ART.

Indoor volatile organic compounds exposures and risk of childhood acute leukemia: a case-control study in shanghai

A case-control study was conducted to investigate the relationship between indoor air pollution and childhood acute leukemia (AL) in Shanghai. 97 cases and 148 gender-, age-, and residence-matched controls were included. Indoor air pollution was evaluated by questionnaires and quantitative measurement including 14 volatile organic compounds (VOCs) and nitrogen dioxide (NO₂) in the homes of the two groups. The levels of individual VOCs, VOC families, TVOC (sum of the concentrations of the individual VOCs) and NO₂ were compared between the two groups. Exposure to styrene and butyl alcohol were associated with an increased risk of childhood AL (styrene: odds ratio (OR)=2.33, 95% confidence interval (CI): 1.07-5.07; butyl alcohol: OR = 2.51, 95%CI: 1.19-5.28); 4th quartile of chlorinated hydrocarbons (OR = 2.52, 95%CI: 1.02-6.26) and 3rd quartile of TVOC (OR = 4.03, 95%CI: 1.06-6.81) had significant higher ORs for childhood AL compared with that in the lowest quartiles. Elevated levels of individual VOCs, VOC families and TVOC were also associated with self-reported risk factors. Our findings suggest that VOCs exposure was associated with an elevated risk of childhood AL, underscore that more attention should be paid to indoor air pollution as a risk factor of childhood AL.

Air pollutants disrupt iron homeostasis to impact oxidant generation, biological effects, and tissue injury

Air pollutants cause changes in iron homeostasis through: 1) a capacity of the pollutant, or a metabolite(s), to complex/chelate iron from pivotal sites in the cell or 2) an ability of the pollutant to displace iron from pivotal sites in the cell. Through either pathway of disruption in iron homeostasis, metal previously employed in essential cell processes is sequestered after air pollutant exposure. An absolute or functional cell iron deficiency results. If enough iron is lost or is otherwise not available within the cell, cell death ensues. However, prior to death, exposed cells will attempt to reverse the loss of requisite metal. This response of the cell includes increased expression of metal importers (e.g. divalent metal transporter 1). Oxidant generation after exposure to air pollutants includes superoxide production which functions in ferrireduction necessary for cell iron import. Activation of kinases and phosphatases and transcription factors and increased release of pro-inflammatory mediators also result from a cell iron deficiency, absolute or functional, after exposure to air pollutants. Finally, air pollutant exposure culminates in the development of inflammation and fibrosis which is a tissue response to the iron deficiency challenging cell survival. Following the response of increased expression of importers and ferrireduction, activation of kinases and phosphatases and transcription factors, release of pro-inflammatory mediators, and inflammation and fibrosis, cell iron is altered, and a new metal homeostasis is established. This new metal homeostasis includes increased total iron concentrations in cells with metal now at levels sufficient to meet requirements for continued function.

Potential biomarkers and antagonists for fluoranthene-induced cellular toxicity of bone marrow derived mesenchymal stem cells

Background

Fluoranthene (FR) is a common environmental pollutant that exists in a complex mixture with other polycyclic aromatic hydrocarbons (PAHs). We identified biomarkers for monitoring FR exposure and investigated the rescue effect of FR-induced cellular toxicity via aryl hydrocarbon receptor (AHR) antagonist activity in bone marrow derived mesenchymal stem cells (BM-MSCs).

Methods

Morphological changes, viability, and rescue effects of an AHR antagonist (CH223191) were examined in BM-MSCs after exposure to FR. Cytotoxic effects were assayed using the tetrazolium-based colorimetric assay. Apoptosis was measured by annexin V and propidium iodide dye-based flowcytometry assay, mitochondrial membrane potential assay, and nuclear DNA fragmentation assay. Molecular signaling pathways of apoptosis and autophagy were investigated using immunoblotting. Proteomics were performed in order to reveal the spectra of cellular damage and identify biomarkers for FR exposure.

Results

Exposing BM-MSCs to FR (IC₅₀=50 µM) induced cell death and morphological changes, while the AHR antagonist showed rescue effects. Autophagy was activated and mitochondrial membrane potential was decreased. Proteomic analysis identified 48 deregulated proteins (26 upregulated and 22 downregulated). Among them, annexin A6, pyruvate kinase, UDP-glucose dehydrogenase, and phospholipase A2 could be potential biomarkers for FR exposure.

Conclusion

The exposure of BM-MSCs to FR induced remarkable alterations in cellular biology and the proteome, allowing for identification of novel biomarkers for FR exposure. Furthermore, AHR antagonists might be able to prevent cellular damage due to FR exposure.

Association of genes ARID5B, CEBPE and folate pathway with acute lymphoblastic leukemia in a population from the Brazilian Amazon region

Acute Lymphoblastic Leukemia (ALL) is the most common childhood neoplasia. Studies have shown that susceptibility to ALL may be modulated by genetic variables. Our study investigated 21 genetic variants in the susceptibility of the population of the Brazilian Amazon region to B-cell ALL. The variants of the genes GGH, CEBPE, ARID5B, MTHFR and MTHFD1 were related to a protective effect against the development of ALL, whereas the variant of the gene ATIC was associated with a risk effect. The results suggest that genetic variants analyzed modulate of the risk of developing ALL in the studied population.

Tobacco smoke exposure and the risk of childhood acute lymphoblastic leukemia and acute myeloid leukemia: A meta-analysis

OBJECTIVE

Tobacco smoke contains carcinogens known to damage somatic and germ cells. In this study, we investigated the effect of tobacco smoking on the risk of childhood acute lymphoblastic leukemia (ALL) and myeloid leukemia (AML).

METHODS

Information about tobacco smoking exposures of the mother before, during, and after pregnancy was collected via PubMed, Embase, and Web of Science databases through November 5, 2018. We performed to evaluate the association between smoking exposure and the risk of childhood ALL and AML. Study selection, data abstraction, and quality assessment were performed by 2 independent reviewers. Random effects models were used to obtain summary odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Nineteen case-control studies of childhood leukemia (age < 15 years) conducted in 9 countries from 1974 to 2018. Maternal smoking exposures did not a significant association with childhood ALL (OR = 1.004, 95% CI 0.953-1.058, P = .881) and AML (OR = 0.92, 95% CI 0.815-1.038, P = .177) during exposure time windows. However, there was an association with paternal smoking and ALL (OR = 1.15, 95% CI 1.038-1.275, P = .007). Paternal smoking in AML showed there was no association with smoking exposures and childhood AML (OR = 1.133, 95% CI 0.943-1.362, P = .181). Next, maternal daily cigarettes consumption showed no associations with ALL (OR = 1.08, 95% CI 1.000-1.168, P = .051) during pregnancy. No association with maternal daily smoking and AML (OR = 0.909, 95% CI 0.682-1.211, P = .514). Paternal daily cigarettes consumption was associated with increased risks of childhood ALL (OR = 1.200, 95% CI 1.112-1.302, P = .000). The higher consumption of paternal smoking (more than 10 per day) was significantly related to childhood ALL. Paternal daily smoking consumption also was related to AML (OR = 1.242, 95% CI 1.031-1.496, P = .022).

CONCLUSION

Maternal smoking before, during, or after pregnancy was not associated with childhood ALL or AML. However, paternal smoking was related to a significantly elevated risk of childhood ALL during pregnancy, but not for AML. Maternal daily smoking consumption was not associated with ALL or AML during pregnancy. The higher consumption of paternal smoking were, the higher the risk of childhood ALL or AML.

The toxicology of air pollution predicts its epidemiology

The epidemiologic investigation has successively delineated associations of air pollution exposure with non-malignant and malignant lung disease, cardiovascular disease, cerebrovascular disease, pregnancy outcomes, perinatal effects and other extra-pulmonary disease including diabetes. Defining these relationships between air pollution exposure and human health closely parallels results of an earlier epidemiologic investigation into cigarette smoking and environmental tobacco smoke (ETS), two other particle-related exposures. Humic-like substances (HULIS) have been identified as a chemical component common to cigarette smoke and air pollution particles. Toxicology studies provide evidence that a disruption of iron homeostasis with sequestration of host metal by HULIS is a fundamental mechanistic pathway through which biological effects are initiated by cigarette smoke and air pollution particles. As a result of a common chemical component and a shared mechanistic pathway, it should be possible to extrapolate from the epidemiology of cigarette smoking and ETS to predict associations of air pollution exposure with human disease, which are currently unrecognized. Accordingly, it is anticipated that the forthcoming epidemiologic investigation will demonstrate relationships of air pollution with COPD causation, peripheral vascular disease, hypertension, renal disease, digestive disease, loss of bone mass/risk of fractures, dental disease, eye disease, fertility problems, and extrapulmonary malignancies.

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.

From sperm to offspring: Assessing the heritable genetic consequences of paternal smoking and potential public health impacts

Individuals who smoke generally do so with the knowledge of potential consequences to their own health. What is rarely considered are the effects of smoking on their future children. The objective of this work was to review the scientific literature on the effects of paternal smoking on sperm and assess the consequences to offspring. A literature search identified over 200 studies with relevant data in humans and animal models. The available data were reviewed to assess the weight of evidence that tobacco smoke is a human germ cell mutagen and estimate effect sizes. These results were used to model the potential increase in genetic disease burden in offspring caused by paternal smoking, with specific focus on aneuploid syndromes and intellectual disability, and the socioeconomic impacts of such an effect. The review revealed strong evidence that tobacco smoking is associated with impaired male fertility, and increases in DNA damage, aneuploidies, and mutations in sperm. Studies support that these effects are heritable and adversely impact the offspring. Our model estimates that, with even a modest 25% increase in sperm mutation frequency caused by smoke-exposure, for each generation across the global population there will be millions of smoking-induced de novo mutations transmitted from fathers to offspring. Furthermore, paternal smoking is estimated to contribute to 1.3 million extra cases of aneuploid pregnancies per generation. Thus, the available evidence makes a compelling case that tobacco smoke is a human germ cell mutagen with serious public health and socio-economic implications. Increased public education should be encouraged to promote abstinence from smoking, well in advance of reproduction, to minimize the transmission of harmful mutations to the next-generation.

Childhood Leukemia: A Preventable Disease

In contrast to most pediatric cancers, there is a growing body of literature, nationally and internationally, that has implicated the role of several environmental indoor and outdoor hazards in the etiology of childhood leukemia. For example, exposures to solvents, traffic, pesticides, and tobacco smoke have consistently demonstrated positive associations with the risk of developing childhood leukemia. Intake of vitamins and folate supplementation during the preconception period or pregnancy has been demonstrated to have a protective effect. Despite the strength of these findings, the dissemination of this knowledge to clinicians has been limited. Some children may be more vulnerable than others as documented by the high and increasing incidence of childhood leukemia in Hispanics. To protect children's health, it is prudent to establish programs to alter exposure to those factors with well-established associations with leukemia risk rather than to suspend judgment until no uncertainty remains. This is particularly true because other serious health outcomes (both negative and positive) have been associated with the same exposures. We draw from historical examples to put in perspective the arguments of association versus causation, as well as to discuss benefits versus risks of immediate and long-term preventive actions.

Tobacco Smoke and Ras Mutations Among Latino and Non-Latino Children with Acute Lymphoblastic Leukemia

BACKGROUND AND AIMS

Childhood acute lymphoblastic leukemia (ALL) is a biologically heterogeneous disease, and mutations in the KRAS and NRAS oncogenes are present at diagnosis in about one-fifth of cases. Ras mutations were previously associated with environmental exposures in leukemias as well as in many other cancer types. This study examined whether Ras mutation could define a unique etiologic group of childhood ALL associated with tobacco smoke, a well-established mutagen and carcinogen.

METHODS

We included 670 children with ALL enrolled in a case-control study in California (1995-2013), including 50.6% Latinos. Parental and child exposure to tobacco smoke was obtained from interviews. Sanger sequencing was used to detect the common KRAS and NRAS hotspot mutations in diagnostic bone marrow DNA. ALL cases were also characterized for common chromosome abnormalities. In case-case analyses, logistic regression analyses were used to estimate odds ratios to describe the association between tobacco smoke exposure and childhood ALL with Ras mutations.

RESULTS

KRAS or NRAS mutations were detected in ∼18% of children diagnosed with ALL. Ras mutations were more common among Latino cases compared with non-Latino whites and in high-hyperdiploid ALL. No associations were observed between parental smoking or child's passive exposure to smoke and Ras positive ALL.

CONCLUSIONS

The apparent lack of association between tobacco smoke and Ras mutation in childhood ALL suggests that Ras mutations do not specifically define a tobacco-related etiologic pathway. Reasons for racial and ethnic differences in ALL are not well understood and could reflect differences in etiology that warrant further examination.

Maternal diet quality before pregnancy and risk of childhood leukaemia

Previous studies on maternal nutrition and childhood leukaemia risk have focused on the role of specific nutrients such as folate and have not considered broader measures of diet quality, which may better capture intake of diverse nutrients known to impact fetal development. We examined the relationship between maternal diet quality before pregnancy, as summarised by a diet quality index, and risk of childhood acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML) in a case-control study in California. Dietary intake in the year before pregnancy was assessed using FFQ in 681 ALL cases, 103 AML cases and 1076 matched controls. Conditional logistic regression was used to estimate OR and 95 % CI for diet quality continuous score and quartiles (Q1-Q4). Higher maternal diet quality score was associated with reduced risk of ALL (OR 0·66; 95 % CI 0·47, 0·93 for Q4 v. Q1) and possibly AML (OR 0·42; 95 % CI 0·15, 1·15 for Q4 v. Q1). No single index component appeared to account for the association. The association of maternal diet quality with risk of ALL was stronger in children diagnosed under the age of 5 years and in children of women who did not report using vitamin supplements before pregnancy. These findings suggest that the joint effects of many dietary components may be important in influencing childhood leukaemia risk.

Childhood Leukemia and Primary Prevention

Leukemia is the most common pediatric cancer, affecting 3800 children per year in the United States. Its annual incidence has increased over the last decades, especially among Latinos. Although most children diagnosed with leukemia are now cured, many suffer long-term complications, and primary prevention efforts are urgently needed. The early onset of leukemia-usually before 5 years of age-and the presence at birth of "pre-leukemic" genetic signatures indicate that pre- and postnatal events are critical to the development of the disease. In contrast to most pediatric cancers, there is a growing body of literature-in the United States and internationally-that has implicated several environmental, infectious, and dietary risk factors in the etiology of childhood leukemia, mainly for acute lymphoblastic leukemia, the most common subtype. For example, exposures to pesticides, tobacco smoke, solvents, and traffic emissions have consistently demonstrated positive associations with the risk of developing childhood leukemia. In contrast, intake of vitamins and folate supplementation during the preconception period or pregnancy, breastfeeding, and exposure to routine childhood infections have been shown to reduce the risk of childhood leukemia. Some children may be especially vulnerable to these risk factors, as demonstrated by a disproportionate burden of childhood leukemia in the Latino population of California. The evidence supporting the associations between childhood leukemia and its risk factors-including pooled analyses from around the world and systematic reviews-is strong; however, the dissemination of this knowledge to clinicians has been limited. To protect children's health, it is prudent to initiate programs designed to alter exposure to well-established leukemia risk factors rather than to suspend judgment until no uncertainty remains. Primary prevention programs for childhood leukemia would also result in the significant co-benefits of reductions in other adverse health outcomes that are common in children, such as detriments to neurocognitive development.

A review of fundamental principles for animal models of DOHaD research: an Australian perspective

Epidemiology formed the basis of ‘the Barker hypothesis’, the concept of ‘developmental programming’ and today’s discipline of the Developmental Origins of Health and Disease (DOHaD). Animal experimentation provided proof of the underlying concepts, and continues to generate knowledge of underlying mechanisms. Interventions in humans, based on DOHaD principles, will be informed by experiments in animals. As knowledge in this discipline has accumulated, from studies of humans and other animals, the complexity of interactions between genome, environment and epigenetics, has been revealed. The vast nature of programming stimuli and breadth of effects is becoming known. As a result of our accumulating knowledge we now appreciate the impact of many variables that contribute to programmed outcomes. To guide further animal research in this field, the Australia and New Zealand DOHaD society (ANZ DOHaD) Animals Models of DOHaD Research Working Group convened at the 2nd Annual ANZ DOHaD Congress in Melbourne, Australia in April 2015. This review summarizes the contributions of animal research to the understanding of DOHaD, and makes recommendations for the design and conduct of animal experiments to maximize relevance, reproducibility and translation of knowledge into improving health and well-being.

Parental Tobacco Smoking and Acute Myeloid Leukemia: The Childhood Leukemia International Consortium

The association between tobacco smoke and acute myeloid leukemia (AML) is well established in adults but not in children. Individual-level data on parental cigarette smoking were obtained from 12 case-control studies from the Childhood Leukemia International Consortium (CLIC, 1974-2012), including 1,330 AML cases diagnosed at age <15 years and 13,169 controls. We conducted pooled analyses of CLIC studies, as well as meta-analyses of CLIC and non-CLIC studies. Overall, maternal smoking before, during, or after pregnancy was not associated with childhood AML; there was a suggestion, however, that smoking during pregnancy was associated with an increased risk in Hispanics (odds ratio = 2.08, 95% confidence interval (CI): 1.20, 3.61) but not in other ethnic groups. By contrast, the odds ratios for paternal lifetime smoking were 1.34 (95% CI: 1.11, 1.62) and 1.18 (95% CI: 0.92, 1.51) in pooled and meta-analyses, respectively. Overall, increased risks from 1.2- to 1.3-fold were observed for pre- and postnatal smoking (P < 0.05), with higher risks reported for heavy smokers. Associations with paternal smoking varied by histological type. Our analyses suggest an association between paternal smoking and childhood AML. The association with maternal smoking appears limited to Hispanic children, raising questions about ethnic differences in tobacco-related exposures and biological mechanisms, as well as study-specific biases.

Male obesity and subfertility, is it really about increased adiposity?

The prevalence of overweight and obesity in reproductive-aged men is increasing worldwide, with >70% of men >18 years classified as overweight or obese in some western nations. Male obesity is associated with male subfertility, impairing sex hormones, reducing sperm counts, increasing oxidative sperm DNA damage and changing the epigenetic status of sperm. These changes to sperm function as a result of obesity, are further associated with impaired embryo development, reduced live birth rates and increased miscarriage rates in humans. Animal models have suggested that these adverse reproductive effects can be transmitted to the offspring; suggesting that men's health at conception may affect the health of their children. In addition to higher adiposity, male obesity is associated with comorbidities, including metabolic syndrome, hypercholesterolemia, hyperleptinemia and a pro-inflammatory state, all which have independently been linked with male subfertility. Taken together, these findings suggest that the effects of male obesity on fertility are likely multifactorial, with associated comorbidities also influencing sperm, pregnancy and subsequent child health.

Dust metal loadings and the risk of childhood acute lymphoblastic leukemia

We evaluated the relationship between the risk of childhood acute lymphoblastic leukemia (ALL) and the levels of metals in carpet dust. A dust sample was collected from the homes of 142 ALL cases and 187 controls participating in the California Childhood Leukemia Study using a high volume small surface sampler (2001-2006). Samples were analyzed using microwave-assisted acid digestion in combination with inductively coupled plasma mass spectrometry for arsenic, cadmium, chromium, copper, lead, nickel, tin, tungsten, and zinc. Eight metals were detected in at least 85% of the case and control homes; tungsten was detected in <15% of homes. Relationships between dust metal loadings (μg metal per m(2) carpet) and ALL risk were modeled using multivariable logistic regression, adjusting for the child's age, sex, and race/ethnicity and confounders, including household annual income. A doubling of dust metal loadings was not associated with significant changes in ALL risk (odds ratio (95% confidence interval): arsenic: 0.96 (0.86, 1.07), cadmium: 0.92 (0.81, 1.05), chromium: 1.01 (0.90, 1.14), copper: 0.97 (0.91, 1.03), lead: 1.01 (0.93, 1.10), nickel: 0.95 (0.82, 1.09), tin: 0.96 (0.86, 1.08), and zinc: 0.94 (0.84, 1.05)). Our findings do not support the hypothesis that metals in carpet dust are risk factors for childhood ALL.

Preconception diet or exercise intervention in obese fathers normalizes sperm microRNA profile and metabolic syndrome in female offspring

Obesity and type 2 diabetes are increasingly prevalent across all demographics. Paternal obesity in humans and rodents can program obesity and impair insulin sensitivity in female offspring. It remains to be determined whether these perturbed offspring phenotypes can be improved through targeted lifestyle interventions in the obese father. Using a mouse model, we demonstrate that diet or exercise interventions for 8 wk (2 rounds of spermatogenesis) in obese founder males restores insulin sensitivity and normalized adiposity in female offspring. Founder diet and/or exercise also normalizes abundance of X-linked sperm microRNAs that target genes regulating cell cycle and apoptosis, pathways central to oocyte and early embryogenesis. Additionally, obesity-associated comorbidities, including inflammation, glucose intolerance, stress, and hypercholesterolemia, were good predictors for sperm microRNA abundance and offspring phenotypes. Interventions aimed at improving paternal metabolic health during specific windows prior to conception can partially normalize aberrant epigenetic signals in sperm and improve the metabolic health of female offspring.

Prenatal recruitment of participants for a birth cohort study including cord blood collection: results of a feasibility study in Bremen, Germany

BACKGROUND

Prospective birth cohort studies comprising follow up of children from pregnancy or birth over a long period of time, and collecting various biological samples at different times through the life-course offer a promising approach to enhance etiologic knowledge of various diseases. Especially for those where early lifetime exposures and conditions are thought to play an important role. The collection and storage of biological samples is a critical component in epidemiological studies, notably for research regarding prenatal exposures to various environmental factors as well as for DNA extraction. Our feasibility study for a birth cohort within the scope of etiology of childhood leukemia with prospective sampling of mothers and their future newborns aimed to investigate the willingness of pregnant women to participate in a birth cohort study involving collection of blood and umbilical cord blood samples. The overall aim was to develop practice-based research recommendations for a possible German birth cohort study.

METHODS

The study was conducted in Bremen, Germany, between January 2012 and March 2013. Pregnant women were eligible for recruitment if (i) their expected date of delivery was during the study recruitment phase (September 2012-February 2013), (ii) they planned to give birth at the cooperating hospital's obstetric unit and (iii) their knowledge of the German language was sufficient to understand study materials, details of participation and to fill out the prenatal self-administered questionnaire. Maternal blood and umbilical cord blood samples to be used for later research activities were collected and stored at a stem cell bank already collaborating with the hospital. 22 primary care gynecologists were invited to enroll pregnant women for the study and cooperation with one hospital was established. Expectant women were recruited during the last trimester of pregnancy, either during one of their prenatal care visits at their primary care gynecologist or later on in hospital by the attending obstetricians or project staff.

RESULTS

Of the 22 invited primary care gynecologists requested to enroll pregnant women for the study, 8 gynecologists actually collaborated. A total of 200 eligible women were invited to participate in the study, 48 (24%) of whom agreed. 34 women were enrolled by primary care gynecologists, with one gynecologist enrolling 26 women. Twelve of 14 women recruited via hospitals were enrolled by study staff. A total of 41 women consented to the collection of umbilical cord blood and maternal blood samples, and samples could be stored for 54% of them. Reason for non-participation were the uncertainty whether or not the full study would be conducted and the fact that the participants were not willing to decide for their children whether or not genetic information (cord blood) can be stored for research purposes.

CONCLUSION

Enrolling parents in a birth cohort study that includes biosampling is a challenge, but participation can be improved through close collaboration with primary care gynecologists and maternity hospitals. Cord blood collection may impede participation, especially when maternity hospitals offer an alternative option for cord blood donation.

Peri-conception parental obesity, reproductive health, and transgenerational impacts

Maternal over-nutrition during pregnancy is a risk factor for pregnancy complications and is increasingly associated with adverse childhood outcomes such as increased propensity for obesity and metabolic disease. However, there is emerging evidence that parental lifestyle factors prior to and at conception have a powerful impact on the health of the offspring for more than one generation. Maternal and paternal obesity prior to conception alters the molecular composition of both oocytes and sperm, which can partly escape epigenetic reprogramming at fertilization, altering the developmental trajectory of the resultant embryo, ultimately increasing the incidence of obesity and metabolic disorders in offspring. Understanding the molecular underpinning of these changes may help create interventions to reduce the risk of disease in future generations.

Biome depletion in conjunction with evolutionary mismatches could play a role in the etiology of neurofibromatosis 1

Neurofibromatosis 1 (NF1) arises de novo in a striking 30-50% of cases, pointing toward an environmental etiology, though none has been clearly identified. The Biome Depletion Theory posits that the absence of mutualistic and commensal organisms within the human body coupled with modern lifestyle alterations may have profoundly deleterious effects, inclusive of immunologic derangement that is thought to result in allergy, atopy, and numerous autoimmune diseases. Biome depletion has been implicated as a factor in the etiology of both multiple sclerosis and autism spectrum disorders; biome reconstitution, i.e. replenishment of the biome with certain keynote species, is being used in the treatment of these and other autoimmune states. Neurofibromatosis 1 has been associated with allergy, various autoimmune states, multiple sclerosis, and autism. Recent research has posited that NF1, multiple sclerosis and autism may all arise from disturbances in the neural crest during gestation. This paper hypothesizes that there is indirect evidence that a highly inflammatory uterine state may precipitate epigenetic changes in vulnerable NF-related genes in the course of fetal development. The etiology of NF1 may lie in the absence of immunomodulation by commensal and mutualistic species once ubiquitously present in the environment, as well as through adoption of a modern lifestyle that contributes to chronic inflammation. Replenishment of helminths and other missing organisms to the human biome prior to conception as well as addressing nutritional status, psychological stress, and environmental exposures may prevent the development of NF1.

Tobacco smoke and risk of childhood acute non-lymphocytic leukemia: findings from the SETIL study

BACKGROUND

Parental smoking and exposure of the mother or the child to environmental tobacco smoke (ETS) as risk factors for Acute non-Lymphocytic Leukemia (AnLL) were investigated.

METHODS

Incident cases of childhood AnLL were enrolled in 14 Italian Regions during 1998-2001. We estimated odds ratios (OR) and 95% confidence intervals (95%CI) conducting logistic regression models including 82 cases of AnLL and 1,044 controls. Inverse probability weighting was applied adjusting for: age; sex; provenience; birth order; birth weight; breastfeeding; parental educational level age, birth year, and occupational exposure to benzene.

RESULTS

Paternal smoke in the conception period was associated with AnLL (OR for ≥ 11 cigarettes/day  = 1.79, 95% CI 1.01-3.15; P trend 0.05). An apparent effect modification by maternal age was identified: only children of mothers aged below 30 presented increased risks. We found weak statistical evidence of an association of AnLL with maternal exposure to ETS (OR for exposure>3 hours/day  = 1.85, 95%CI 0.97-3.52; P trend 0.07). No association was observed between AnLL and either maternal smoking during pregnancy or child exposure to ETS.

CONCLUSIONS

This study is consistent with the hypothesis that paternal smoke is associated with AnLL. We observed statistical evidence of an association between maternal exposure to ETS and AnLL, but believe bias might have inflated our estimates.

Descriptive Epidemiology in Mexican children with cancer under an open national public health insurance program

Background

All the children registered at the National Council for the Prevention and Treatment of Childhood Cancer were analyzed. The rationale for this Federal Government Council is to financially support the treatment of all children registered into this system. All patients are within a network of 55 public certified hospitals nationwide.

Methods

In the current study, data from 2007 to 2012 are presented for all patients (0–18 years) with a pathological diagnosis of leukemia, lymphoma and solid tumors. The parameters analyzed were prevalence, incidence, mortality, and abandonment rate.

Results

A diagnosis of cancer was documented in 14,178 children. The incidence was of 156.9/million/year (2012). The median age was 4.9. The most common childhood cancer is leukemia, which occurs in 49.8% of patients (2007–2012); and has an incidence rate of 78.1/million/year (2012). The national mortality rate was 5.3/100,000 in 2012, however in the group between 15 to 18 years it reaches a level of 8.6.

Conclusions

The study demonstrates that there is a high incidence of childhood cancer in Mexico. In particular, the results reveal an elevated incidence and prevalence of leukemia especially from 0 to 4 years. Only 4.7% of these patients abandoned treatment. The clinical outcome for all of the children studied improved since the establishment of this national program.

Polycyclic aromatic hydrocarbons in residential dust and risk of childhood acute lymphoblastic leukemia

Several polycyclic aromatic hydrocarbons (PAHs) are known or probable human carcinogens. We evaluated the relationship between PAH exposure and risk of childhood acute lymphoblastic leukemia (ALL) using concentrations in residential dust as an exposure indicator. We conducted a population-based case-control study (251 ALL cases, 306 birth-certificate controls) in Northern and Central California from 2001 to 2007. We collected residential dust using a high volume small surface sampler (HVS3) (n=185 cases, 212 controls) or by sampling from participants' household vacuum cleaners (n=66 cases, 94 controls). We evaluated log-transformed concentrations of 9 individual PAHs, the summed PAHs, and the summed PAHs weighted by their carcinogenic potency (the toxic equivalence). We calculated odds ratios (ORs) and 95% confidence intervals (CI) using logistic regression adjusting for demographic characteristics and duration between diagnosis/reference date and dust collection. Among participants with HVS3 dust, risk of ALL was not associated with increasing concentration of any PAHs based on OR perln(ng/g). Among participants with vacuum dust, we observed positive associations between ALL risk and increasing concentrations of benzo[a]pyrene (OR perln[ng/g]=1.42, 95% CI=0.95, 2.12), dibenzo[a,h]anthracene (OR=1.98, 95% CI=1.11, 3.55), benzo[k]fluoranthene (OR=1.71, 95% CI=0.91, 3.22), indeno[1,2,3-cd]pyrene (OR=1.81, 95% CI=1.04, 3.16), and the toxic equivalence (OR=2.35, 95% CI=1.18, 4.69). The increased ALL risk among participants with vacuum dust suggests that PAH exposure may increase the risk of childhood ALL; however, reasons for the different results based on HVS3 dust samples deserve further study.

Oxidative stress in mouse sperm impairs embryo development, fetal growth and alters adiposity and glucose regulation in female offspring

Paternal health cues are able to program the health of the next generation however the mechanism for this transmission is unknown. Reactive oxygen species (ROS) are increased in many paternal pathologies, some of which program offspring health, and are known to induce DNA damage and alter the methylation pattern of chromatin. We therefore investigated whether a chemically induced increase of ROS in sperm impairs embryo, pregnancy and offspring health. Mouse sperm was exposed to 1500 µM of hydrogen peroxide (H₂O₂), which induced oxidative damage, however did not affect sperm motility or the ability to bind and fertilize an oocyte. Sperm treated with H₂O₂ delayed on-time development of subsequent embryos, decreased the ratio of inner cell mass cells (ICM) in the resulting blastocyst and reduced implantation rates. Crown-rump length at day 18 of gestation was also reduced in offspring produced by H₂O₂ treated sperm. Female offspring from H₂O₂ treated sperm were smaller, became glucose intolerant and accumulated increased levels of adipose tissue compared to control female offspring. Interestingly male offspring phenotype was less severe with increases in fat depots only seen at 4 weeks of age, which was restored to that of control offspring later in life, demonstrating sex-specific impacts on offspring. This study implicates elevated sperm ROS concentrations, which are common to many paternal health pathologies, as a mediator of programming offspring for metabolic syndrome and obesity.

RAS mutations in early age leukaemia modulated by NQO1 rs1800566 (C609T) are associated with second-hand smoking exposures

BACKGROUND

Deregulation of the MAPK genes signalling caused by somatic mutations have been implied in leukaemia pathogenesis, including RAS mutation (RASmut) in acute myeloid leukaemia (AML), which has been associated with intra-uterine chemical exposures. A case-case study was conducted in order to explore maternal and child exposures to tobacco smoking associations with early age leukaemia (EAL).

METHODS

Covariables of reference were MLL rearrangements (MLL-r), RASmut and NQO1 rs1800566 (C609T). Samples from 150 acute lymphoblastic leukaemia (ALL) and 85 AML were included. Maternal exposures were assessed using a structured questionnaire with demographic, personal habits and residence history information. Restriction fragment length polymorphism and denaturing high performance liquid chromatography were used to screen FLT3, KRAS, and NRAS mutations; direct sequencing was performed to validate the results. NQO1 polymorphism was detected by real-time allelic discrimination technique.

RESULTS

Overall, RASmut were detected in 28.7% of EAL cases; BRAFmut was found only in one AML patient. Higher rate of KRASmut was found in ALL (30.3%) compared to AML (20.8%) with MLL-r; RASmut showed an association with second-hand tobacco smoking exposures (OR, 3.06, 95% CI, 1.03-9.07). A considerable increased risk for EAL with the combination of RASmut and NQO1 609CT (OR, 4.24, 95% CI, 1.24-14.50) was observed.

CONCLUSIONS

Our data demonstrated the increased risk association between maternal smoking and EAL with MLL-r. Additionally, suggests that children second-hand tobacco exposures are associated with increased risk of EAL with RASmut modulated by NQO1 rs1800566 (C609T).

Accuracy of prenatal smoking data from Washington State birth certificates in a population-based sample with cotinine measurements

PURPOSE

To assess the accuracy of smoking data in contemporary U.S. birth certificates.

METHODS

We compared data on prenatal smoking as reported on Washington State birth certificates to cotinine measured in archived newborn screening dried blood spots for 200 infants born in 2007 (100 randomly selected from births to self-reported nonsmokers and 100 born to self-reported smokers). We estimated the sensitivity of the birth certificate data to identify prenatal smokers and the precision with which self-identified third trimester smokers report smoking levels.

RESULTS

Infants born to two (2%) mothers who reported they did not smoke during the pregnancy had whole blood cotinine concentrations consistent with active smoking by the mother (sensitivity 85%). Sensitivity of the birth certificate to identify reported smokers who continued to smoke throughout pregnancy was similar (89%). Among self-identified third trimester smokers whose infants' specimens were collected shortly after delivery, Spearman rho between infant cotinine and maternal-reported cigarettes/day in the third trimester was 0.54.

CONCLUSIONS

Birth certificates may represent a viable option for assessing prenatal smoking status, and possibly smoking cessation and level among smokers, in epidemiologic studies sufficiently powered to overcome a moderate amount of exposure measurement error.

Tobacco smoke exposure and the risk of childhood acute lymphoblastic and myeloid leukemias by cytogenetic subtype

BACKGROUND

Tobacco smoke contains carcinogens known to damage somatic and germ cells. We investigated the effect of tobacco smoke on the risk of childhood acute lymphoblastic leukemia (ALL) and myeloid leukemia (AML), especially subtypes of prenatal origin such as ALL with translocation t(12;21) or high-hyperdiploidy (51-67 chromosomes).

METHODS

We collected information on exposures to tobacco smoking before conception, during pregnancy, and after birth in 767 ALL cases, 135 AML cases, and 1,139 controls (1996-2008). Among cases, chromosome translocations, deletions, or aneuploidy were identified by conventional karyotype and fluorescence in situ hybridization.

RESULTS

Multivariable regression analyses for ALL and AML overall showed no definite evidence of associations with self-reported (yes/no) parental prenatal active smoking and child's passive smoking. However, children with history of paternal prenatal smoking combined with postnatal passive smoking had a 1.5-fold increased risk of ALL [95% confidence interval (CI), 1.01-2.23], compared to those without smoking history (ORs for pre- or postnatal smoking only were close to one). This joint effect was seen for B-cell precursor ALL with t(12;21) (OR = 2.08; 95% CI, 1.04-4.16), but not high hyperdiploid B-cell ALL. Similarly, child's passive smoking was associated with an elevated risk of AML with chromosome structural changes (OR = 2.76; 95% CI, 1.01-7.58), but not aneuploidy.

CONCLUSIONS

Our data suggest that exposure to tobacco smoking was associated with increased risks of childhood ALL and AML; and risks varied by timing of exposure (before and/or after birth) and cytogenetic subtype, based on imprecise estimates.

IMPACT

Parents should limit exposures to tobacco smoke before and after the child's birth.

Smad3 mediates cigarette smoke extract (CSE) induction of VEGF release by human fetal lung fibroblasts

Cigarette smoke is the major cause of chronic obstructive pulmonary disease (COPD), yet pathogenic mechanisms are not fully understood. Vascular endothelial growth factor (VEGF) is one of the major regulators of endothelial cell survival and is believed to play a role in the pathogenesis of COPD. Fibroblasts are a significant source of VEGF in the lungs; however the effect of cigarette smoke exposure on VEGF release by fibroblasts is not fully understood. We hypothesized that cigarette smoke-induced disturbed VEGF release by human lung fibroblasts is a potential pathogenic mechanism that could contribute to COPD. Cigarette smoke extract (CSE) was prepared by modification of the methods of Carp and Janoff (American Review of Respiratory Disease, 1978). Human fetal lung fibroblasts (HFL-1) were exposed to different concentrations of CSE and for different durations. VEGF release into the media was measured using ELISA. TGF-β1 receptor (TβR1)/Smad3 as a potential pathway for CSE modulated VEGF release was also investigated using biochemical analyses and siRNA inhibition of Smad3 and siRNA and pharmacologic inhibition of TβR1. CSE induced VEGF release by HFL-1 in concentration and time dependent manner. This was confirmed in two additional types of primary human fetal lung fibroblasts. CSE induced Smad3 phosphorylation and nuclear translocation in HFL-1 cells. Silencing of Smad3 by siRNA not only eliminated the stimulatory effect of CSE on VEGF release but also inhibited baseline VEGF production. Suppression of TβR1 by the pharmacological inhibitor (SB431542) markedly reduced VEGF release by HFL-1 in response to CSE and this effect was confirmed by TβR1 siRNA. In contrast, nicotine inhibited VEGF release by HFL-1 in a dose and time dependent manner. Our findings indicate that CSE stimulates Smad3-mediated VEGF release by lung fibroblasts. Nicotine does not account for the CSE stimulation of VEGF in HFL-1. The ability of lung fibroblasts to produce VEGF may play a role in pathogenesis of cigarette smoke induced lung disease.

The Impact of Paternal and Maternal Smoking on Semen Quality of Adolescent Men

Background

Maternal smoking during pregnancy has been reported to negatively impact sperm counts of the sons. Sufficient data on the effect of paternal smoking is lacking.

Objectives

We wished to elucidate the impact of maternal and paternal smoking during pregnancy and current own smoking on reproductive function of the male offspring.

Methods

Semen parameters including sperm DNA integrity were analyzed in 295 adolescents from the general population close to Malmö, Sweden, recruited for the study during 2008–2010. Information on maternal smoking was obtained from the Swedish Medical Birth Register, and regarding own and paternal smoking from questionnaires. The impacts of maternal, paternal and own smoking were evaluated in a multivariate regression model and by use of models including interaction terms. Totally, three exposures and five outcomes were evaluated.

Results

In maternally unexposed men, paternal smoking was associated with 46% lower total sperm count (95%CI: 21%, 64%) in maternally unexposed men. Both paternal and maternal smoking were associated with a lower sperm concentration (mean differences: 35%; 95%CI: 8.1%, 55% and 36%; 95%CI: 3.9%, 57%, respectively) if the other parent was a non-smoker. No statistically significant impact of own smoking on semen parameters was seen.

Conclusions

Prenatal both maternal and paternal smoking were separately associated with some decrease in sperm count in men of whom the other parent was not reported to smoke.

Impact of obesity on male fertility, sperm function and molecular composition

Male obesity in reproductive-age men has nearly tripled in the past 30 y and coincides with an increase in male infertility worldwide. There is now emerging evidence that male obesity impacts negatively on male reproductive potential not only reducing sperm quality, but in particular altering the physical and molecular structure of germ cells in the testes and ultimately mature sperm. Recent data has shown that male obesity also impairs offspring metabolic and reproductive health suggesting that paternal health cues are transmitted to the next generation with the mediator mostly likely occurring via the sperm. Interestingly the molecular profile of germ cells in the testes and sperm from obese males is altered with changes to epigenetic modifiers. The increasing prevalence of male obesity calls for better public health awareness at the time of conception, with a better understanding of the molecular mechanism involved during spermatogenesis required along with the potential of interventions in reversing these deleterious effects. This review will focus on how male obesity affects fertility and sperm quality with a focus on proposed mechanisms and the potential reversibility of these adverse effects.

Perspectives on the causes of childhood leukemia

Acute leukemia is the most common cancer in children but the causes of the disease in the majority of cases are not known. About 80% are precursor-B cell in origin (CD19+, CD10+), and this immunophenotype has increased in incidence over the past several decades in the Western world. Part of this increase may be due to the introduction of new chemical exposures into the child's environment including parental smoking, pesticides, traffic fumes, paint and household chemicals. However, much of the increase in leukemia rates is likely linked to altered patterns of infection during early childhood development, mirroring causal pathways responsible for a similarly increased incidence of other childhood-diagnosed immune-related illnesses including allergy, asthma, and type 1 diabetes. Factors linked to childhood leukemia that are likely surrogates for immune stimulation include exposure to childcare settings, parity status and birth order, vaccination history, and population mixing. In case-control studies, acute lymphoblastic leukemia (ALL) is consistently inversely associated with greater exposure to infections, via daycare and later birth order. New evidence suggests also that children who contract leukemia may harbor a congenital defect in immune responder status, as indicated by lower levels of the immunosuppressive cytokine IL-10 at birth in children who grow up to contract leukemia, as well as higher need for clinical care for infections within the first year of life despite having lower levels of exposure to infections. One manifestation of this phenomenon may be leukemia clusters which tend to appear as a leukemia "outbreak" among populations with low herd immunity to a new infection. Critical answers to the etiology of childhood leukemia will require incorporating new tools into traditional epidemiologic approaches - including the classification of leukemia at a molecular scale, better exposure assessments at all points in a child's life, a comprehensive understanding of genetic risk factors, and an appraisal of the interplay between infectious exposures and the status of immune response in individuals.

Maternal smoking during pregnancy and risk for childhood leukemia: a nationwide case-control study in Greece and meta-analysis

BACKGROUND

Maternal smoking during pregnancy has been often implicated in the development of childhood leukemia with ambiguous results. Hence, we conducted a meta-analysis aiming to summarize current evidence and quantify any tentative impact.

PROCEDURE

We retrieved one cohort (553 leukemias compared to 1,440,542 children), 20 case-control studies and also analyzed the updated Greek case-control dataset with unpublished data, yielding in total 11,092 cases and 25,221 controls.

RESULTS

Odds ratios reported in the studies included ranged from 0.70 to 2.20 for acute lymphocytic (ALL) and from 0.60 to 2.17 for acute myelocytic leukemia (AML). The combined effect regarding the association of maternal smoking (any vs. no) and leukemia risk was 1.03 for ALL (95% CI = 0.95-1.12, random effects model) and 0.99 for AML (95% CI = 0.90-1.09, fixed effects model). The results remained unchanged when sensitivity analyses were undertaken of studies reporting same maternal smoking periods, those focusing only on childhood leukemia deaths or investigations which did not clearly define AML subtype.

CONCLUSIONS

The findings of the meta-analysis challenge the limits of traditional epidemiology to provide sound inferences when point estimates of constituent studies range around the null. In particular, this study provides no support to a hypothesis linking maternal smoking during pregnancy with subsequent development of main childhood leukemia subtypes. Further investigations employing molecular and genetic epidemiology, however, might be needed in the hope to reveal even minimal risks pertaining individuals with specific susceptibility to tobacco compounds who sustain high environmental exposures prenatally or postnatally.

Associations between GSTM1 and OGG1 Ser326Cys polymorphisms and smoking on chromosomal damage and birth growth in mothers

The presenting study was investigated the associations between individual susceptibility and cigarette smoke on maternal chromosomal damage and neonatal birth growth in smoking mothers since little known about genetic susceptibility to cigarette smoke in relation to adverse pregnancy outcome such as birth growth. Sixty-one pregnant women who completed a questionnaire at Ankara Education and Research Hospital, Department of Obstetrics and Gynecology have enrolled in this study. GSTM1 and OGG1 ser326Cys gene polymorphisms were analysed by RFLP-PCR (Restriction Fragment Length Polymorphism-Polymerase Chain Reaction) as possible genetic factors affecting susceptibility to such health effects of smoking and chromosomal damage was performed by chromosomal aberration assay (CAA) in maternal blood lymphocytes. Maternal self-reported history of pregnancy smoking was informed by questionnaire declaration. Our results showed that maternal smoking had significant effect on chromosomal damage, birth weight, and length. The frequencies of CA in smokers was significantly higher than that of the nonsmokers (3.46 ± 2.06 and 2.00 ± 1.3, P = 0.001). Birth weight and length in smokers were significantly higher that of nonsmokers (3,355 g and 49.57 cm, P = 0.001; 3,639 g and 50.79 cm, P = 0.002). On the other hand, there was a slightly increased in the frequencies of CA and reduction birth weight and length in GSTM1 null and length in OGG1 variant genotypes, those differences were not statistically significant (P > 0.05); likely due to small sample size. Larger sample size needs to reach significance.

Environmental toxicants and the developing immune system: a missing link in the global battle against infectious disease?

There is now compelling evidence that developmental exposure to chemicals from our environment contributes to disease later in life, with animal models supporting this concept in reproductive, metabolic, and neurodegenerative diseases. In contrast, data regarding how developmental exposures impact the susceptibility of the immune system to functional alterations later in life are surprisingly scant. Given that the immune system forms an integrated network that detects and destroys invading pathogens and cancer cells, it provides the body's first line of defense. Thus, the consequences of early life exposures that reduce immune function are profound. This review summarizes available data for pollutants such as cigarette smoke and dioxin-like compounds, which consistently support the idea that developmental exposures critically impact the immune system. These findings suggest that exposure to common chemicals from our daily environment represent overlooked contributors to the fact that infectious diseases remain among the top five causes of death worldwide.

Benzene exposure in childhood: Role of living environments and assessment of available tools

Benzene is a widespread air pollutant and a well-known human carcinogen. Evidence is needed regarding benzene intake in the pediatric age group. We investigated the use of urinary (u) trans,trans-muconic acid (t,t-MA), S-phenylmercapturic acid (SPMA), and unmodified benzene (UB) for assessing exposure to low concentrations of environmental benzene and the role of living environment on benzene exposure in childhood. u-t,t-MA, u-SPMA, u-UB and u-cotinine were measured in urine samples of 243 Italian children (5-11 years) recruited in a cross-sectional study. Analytical results were compared with data obtained from questionnaires about participants' main potential exposure factors. u-UB, u-t,t-MA and u-SPMA concentrations were about 1.5-fold higher in children living in urban areas than in those in the rural group. Univariate analyses showed that u-UB was the only biomarker able to discriminate secondhand smoke (SHS) exposure in urban and rural children (medians=411.50 and 210.50 ng/L, respectively); these results were confirmed by the strong correlation between u-UB and u-cotinine in the SHS-exposed group and by multivariate analyses. A regression model on u-SPMA showed that the metabolite is related to residence area (p<0.001), SHS exposure (p=0.048) and gender (p=0.027). u-UB is the best marker of benzene exposure in children in the present study, and it can be used as a good carcinogen-derived biomarker of exposure to passive smoking, especially related to benzene, when urine sample is collected at the end of the day. In addition, it is important to highlight that SHS resulted the most important contributor to benzene exposure, underlining the need for an information campaign against passive smoking exposure.

Transgenerational tobacco smoke exposure and childhood cancer: an observational study

AIM

Although tobacco smoke is an established risk factor for adult cancer, studies of the association between parental smoking and childhood cancer have produced inconsistent results. To investigate the transgenerational relationship between pre-natal and post-natal tobacco smoke exposure from the grandmother's pregnancies until after the post-natal period and childhood cancer.

METHODS

Exposure to tobacco smoke was recorded for three generations. Data were collected through personal interviews using the paediatric environmental history, and were compared among 128 children with cancer and 128 matched controls. The contingency tables and a logistic multivariable regression model were used to control for possible confounding factors.

RESULTS

Smoke exposure during oogenesis (maternal grandmother smokers)--odds ratio (OR) 2.2 (95% confidence interval (CI) 1.1-4.9)--and during the mother' pregnancies--OR 1.8 (95% CI 1.1-3.3)--were significantly associated with an increased risk of childhood cancer.

CONCLUSIONS

Tobacco smoke exposure during the grandmother's and mother's pregnancies increase the risk of cancer in the descendants. The results suggest that the biological plausibility of the association between parental smoking and paediatric cancer can be explained by the large latency period of paediatric carcinogenesis.

Epidemiologic mapping of Florida childhood cancer clusters

BACKGROUND

Childhood cancer remains the leading cause of disease-related mortality for children. Whereas, improvement in care has dramatically increased survival, the risk factors remain to be fully understood. The increasing incidence of childhood cancer in Florida may be associated with possible cancer clusters. We aimed, in this study, to identify and confirm possible childhood cancer clusters and their subtypes in the state of Florida.

METHODS

We conducted purely spatial and space-time analyzes to assess any evidence of childhood malignancy clusters in the state of Florida using SaTScan. Data from the Florida Association of Pediatric Tumor Programs (FAPTP) for the period 2000-2007 were used in this analysis.

RESULTS

In the purely spatial analysis, the relative risks (RR) of overall childhood cancer persisted after controlling for confounding factors in south Florida (SF) (RR = 1.36, P = 0.001) and northeastern Florida (NEF) (RR = 1.30, P = 0.01). Likewise, in the space-time analysis, there was a statistically significant increase in cancer rates in SF (RR = 1.52, P = 0.001) between 2006 and 2007. The purely spatial analysis of the cancer subtypes indicated a statistically significant increase in the rate of leukemia and brain/CNS cancers in both SF and NEF, P < 0.05. The space-time analysis indicated a statistically significant sizable increase in brain/CNS tumors (RR = 2.25, P = 0.02) for 2006-2007.

CONCLUSIONS

There is evidence of spatial and space-time childhood cancer clustering in SF and NEF. This evidence is suggestive of the presence of possible predisposing factors in these cluster regions. Therefore, further study is needed to investigate these potential risk factors.

Biological evidence for the acute health effects of secondhand smoke exposure

A vast number of studies on the unfavorable effects of secondhand smoke (SHS) exist within the international literature, the majority of which evaluate longitudinal epidemiological data. Although limited, the experimental studies that assess the acute and short-term effects of exposure to SHS are also increasing in number. They include cellular, animal, and human studies that indicate a number of pathophysiological mechanisms through which the deleterious effects of SHS may arise. This current review evaluates the existing biological evidence regarding the acute health effects of SHS exposure. Analyses on the inhaled toxicants and the carcinogenicity of SHS are included as well as in-depth discussions on the evidence for acute SHS-induced respiratory, cardiovascular, metabolic, endocrine and immune effects, and SHS-induced influences on oxygen delivery and exercise. The influence of the length of exposure and the duration of the observed effects is also described. Moreover, recent findings regarding the underlying pathophysiological mechanisms related to SHS are depicted so as to generate models that describe the SHS-induced effects on different systems within the human body. Based on the presented biological evidence, it is concluded that brief, acute, transient exposures to SHS may cause significant adverse effects on several systems of the human body and represent a significant and acute health hazard. Future research directions in this area include research on the concentrations of tobacco smoke constituents in the alveolar milieu following SHS exposure, individual susceptibility to SHS, as well as the effects of SHS on neurobehavioral activity, brain cell development, synaptic development, and function.

Detection of lung cancer by oral examination

Lung cancer continues to be the leading cause of cancer deaths worldwide. Cigarette smoking is the predominant cause of lung cancer. Researchers found that tobacco-induced molecular changes in the oral epithelium are similar to those in the lung epithelium. Furthermore, there has been considerable progress in investigating the tumorigenesis of oral epithelium using molecular markers. These results offer hope that we can predict lung cancer in smokers by oral examination, which is much easier and more practical than lung biopsy. The hypothesis is to collect oral epithelial cells by gently scraping the oral mucosa, and analyze the DNA variation in these cells using molecular biological methods. Therefore, the oral epithelium is serving as a surrogate tissue for assessing smoking-induced molecular damage to the lungs and thus have important implications for early detection of lung cancer.

A case-only study of interactions between metabolic enzyme polymorphisms and industrial pollution in childhood acute leukemia

Cancer risk is modulated by gene-environment interactions between toxic exposure and genetic variation in carcinogen metabolism. Our objective was to assess interactions between exposure to industrial pollutants and polymorphisms affecting cytochrome P450s (CYP1A1 and CYP2E1) and glutathione S-transferases (GSTP1 and GSTT) in childhood acute leukemia (AL). A case-only design was conducted in 123 Chinese children with sporadic AL. Industrial plants in the vicinity were recorded and, if present, their size and proximity to the usual place of residence of AL children was evaluated. Unconditional logistic regression analysis was performed across the AL study group adjusting for age, gender, parental education, occupation and smoking, indoor and outdoor pesticide use, presence of television sets, refrigerators, microwave ovens and furniture material in children's rooms, and electric transformers, power lines, and telecommunication transmitters within 500 m. This analysis revealed an interaction between the GSTT null allele and industrial plants within 500 m of the residences of childhood AL patients (interaction odds ratio, COR=2.96, 95% CI: 1.09-8.01). Furthermore, the COR for the interaction between GSTT null and industrial plants within 50 m was 5.99 (95% CI: 1.41-25.45). Our results suggest an association between proximity to industrial plants and the GSTT null allele in patients with childhood AL.