Florence Menegaux

Household exposure to pesticides and risk of childhood acute leukaemia

Objectives: To investigate the relation between childhood acute leukaemia and household exposure to pesticides. Methods: The study included 280 incident cases of acute leukaemia and 288 controls frequency matched on gender, age, hospital, and ethnic origin. The data were obtained from standardised face to face interviews of the mothers with detailed questions on parental occupational history, home and garden insecticide use, and insecticidal treatment of pediculosis. Odds ratios were estimated using unconditional regression models including the stratification variables parental socioeconomic status and housing characteristics. Results: Acute leukaemia was observed to be significantly associated with maternal home insecticide use during pregnancy (OR = 1.8, 95% CI 1.2 to 2.8) and during childhood (OR = 1.7, 95% CI 1.1 to 2.4), with garden insecticide use (OR = 2.4, 95% CI 1.3 to 4.3), and fungicide use (OR = 2.5, 95% CI 1.0 to 6.2) during childhood. Insecticidal shampoo treatment of pediculosis was also associated with childhood acute leukaemia (OR = 1.9, 95% CI 1.2 to 3.3). Conclusion: The results reported herein support the hypothesis that various types of insecticide exposure may be a risk factor for childhood acute leukaemia. The observed association with insecticidal shampoo treatment of pediculosis, which has never been investigated before, requires further study.

Childhood leukaemia, polymorphisms of metabolism enzyme genes, and interactions with maternal tobacco, coffee and alcohol consumption during pregnancy.

Metabolic polymorphisms may influence the risk of childhood leukaemia related to maternal tobacco, coffee or alcohol consumption. The data were extracted from a case-control study including 280 cases of acute leukaemia and 288 controls. Blood sampling was obtained for a representative subset of 219 cases and 105 controls. Gene–environment interactions were estimated using both case–control and case-only analyses. The polymorphisms of CYP1A1, GSTM1, GSTP1, GSTT1 and NQO1 were not associated with the risk of leukaemia. The slow EPHX1 allele was negatively associated with childhood leukaemia while an inverse non-significant association was observed with the fast EPHX1 allele. Maternal smoking during pregnancy was not related to leukaemia, but an interaction was observed in the case-only analysis with CYP1A1*2A variant allele (odds ratio (OR) 2.2 [1.0–4.9]) and with GSTM1 deletion (OR 2.3 [1.2–4.4]). Conversely, coffee drinking interacted negatively with NQO1 polymorphism in the case-only analysis (OR 0.6 [0.3–1.2] and 0.4 [0.1–1.0] for light and heavy coffee consumptions, respectively). This study suggests that maternal smoking may be a risk factor for leukaemia in children who carry CYP1A1 or GSTM1 genotypes, which might increase reactive metabolites of polycyclic aromatic hydrocarbons.

Night work and breast cancer: A population-based case–control study in France (the CECILE study)

Night work involving disruption of circadian rhythm was suggested as a possible cause of breast cancer. We examined the role of night work in a large population‐based case‐control study carried out in France between 2005 and 2008. Lifetime occupational history including work schedules of each night work period was elicited in 1,232 cases of breast cancer and 1,317 population controls. Thirteen percent of the cases and 11% of the controls had ever worked on night shifts (OR = 1.27 [95% confidence interval = 0.99–1.64]). Odds ratios were 1.35 [1.01–1.80] in women who worked on overnight shifts, 1.40 [1.01–1.92] in women who had worked at night for 4.5 or more years, and 1.43 [1.01–2.03] in those who worked less than three nights per week on average. The odds ratio was 1.95 [1.13–3.35] in women employed in night work for >4 years before their first full‐term pregnancy, a period where mammary gland cells are incompletely differentiated and possibly more susceptible to circadian disruption effects. Our results support the hypothesis that night work plays a role in breast cancer, particularly in women who started working at night before first full‐term pregnancy.

Childhood Acute Leukemia, Early Common Infections, and Allergy: The ESCALE Study

This study investigated the role of factors considered related to early stimulation of the immune system in the etiology of childhood acute leukemia. The national registry-based case-control study ESCALE was carried out in France in 2003-2004. Population controls were frequency matched to cases on age and gender. Data were obtained from structured telephone questionnaires administered to mothers. Odds ratios were estimated using unconditional regression models adjusted for potential confounders. Included were 634 acute lymphoblastic leukemia cases, 86 acute myeloblastic leukemia cases, and 1,494 controls aged ≥1 year. Negative associations were observed between acute lymphoblastic leukemia and birth order (P for trend < 0.0001), attendance at a day-care center before age 1 year (odds ratio (OR) = 0.8, 95% confidence interval (CI): 0.6, 1.1), prolonged breastfeeding (OR = 0.7, 95% CI: 0.5, 1.0), repeated early common infections (OR = 0.7, 95% CI: 0.6, 0.9), regular contact with farm animals (OR = 0.6, 95% CI: 0.5, 0.8), frequent farm visits in early life (OR = 0.4, 95% CI: 0.3, 0.6), and history of asthma (OR = 0.7, 95% CI: 0.4, 1.0) or eczema (OR = 0.7, 95% CI: 0.6, 0.9). Results support the hypothesis that repeated early infections and asthma may play a role against childhood acute leukemia.

Household Exposure to Pesticides and Risk of Childhood Hematopoietic Malignancies: The ESCALE Study (SFCE)

Objectives We investigated the role of household exposure to pesticides in the etiology of childhood hematopoietic malignancies. Methods The national registry-based case–control study ESCALE (Etude sur les cancers de l’enfant) was carried out in France over the period 2003–2004. Population controls were frequency matched with the cases on age and sex. Maternal household use of pesticides during pregnancy and paternal use during pregnancy or childhood were reported by the mothers in a structured telephone questionnaire. Insecticides (used at home, on pets, or for garden crops), herbicides, and fungicides were distinguished. We estimated odds ratios (ORs) using unconditional regression models closely adjusting for age, sex, degree of urbanization, and type of housing (flat or house). Results We included a total of 764 cases of acute leukemia (AL), 130 of Hodgkin lymphoma (HL), 166 of non-Hodgkin lymphoma (NHL), and 1,681 controls. Insecticide use during pregnancy was significantly associated with childhood AL [OR = 2.1; 95% confidence interval (CI), 1.7–2.5], both lymphoblastic and myeloblastic, NHL (OR = 1.8; 95% CI, 1.3–2.6), mainly for Burkitt lymphoma (OR = 2.7; 95% CI, 1.6–4.5), and mixed-cell HL (OR = 4.1; 95% CI, 1.4–11.8), but not nodular sclerosis HL (OR = 1.1; 95% CI, 0.6–1.9). Paternal household use of pesticides was also related to AL (OR = 1.5; 95% CI, 1.2–1.8) and NHL (OR = 1.7; 95% CI, 1.2–2.6); but for AL the relationships did not remain after adjustment for maternal pesticide use during pregnancy. Conclusion The study findings strengthen the hypothesis that domestic use of pesticides may play a role in the etiology of childhood hematopoietic malignancies. The consistency of the findings with those of previous studies on AL raises the question of the advisability of preventing pesticide use by pregnant women.

Parental smoking, maternal alcohol, coffee and tea consumption during pregnancy and childhood malignant central nervous system tumours: the ESCALE study (SFCE)

Parental smoking and maternal alcohol and caffeinated beverage consumption are prevalent exposures which may play a role, either directly or through their influence on metabolism, in the aetiology of childhood malignant central nervous system (CNS) tumours. The hypothesis was investigated in the Epidemiological Study on childhood Cancer and Leukemia ESCALE study, a national population-based case–control study carried out in France in 2003–2004. The study included 209 incident cases of CNS tumours and 1681 population-based controls, frequency matched with the cases by age and sex. The data were collected through a standardized telephone interview of the biological mothers. No association between maternal smoking during pregnancy and CNS tumours [odds ratio (OR): 1.1 (0.8–1.6)] was observed. Paternal smoking during the year before birth was associated with CNS tumours (P for trend=0.04), particularly astrocytomas [OR: 3.1 (1.3–7.6)]. Maternal alcohol consumption during pregnancy was not associated with CNS tumours. Associations between ependymomas and the highest consumption of coffee [OR: 2.7 (0.9–8.1)] and tea [OR: 2.5 (1.1–5.9)] were observed. A strong association between CNS tumours and the highest maternal consumption of both coffee and tea during pregnancy was observed [OR: 4.4 (1.5–13)]. The results constitute additional evidence for a role of paternal smoking and suggest that maternal coffee and tea consumption during pregnancy may also increase the risk of CNS tumours. The study does not suggest an increased risk of CNS tumours related to alcohol consumption during pregnancy.

Breast cancer risk, nightwork, and circadian clock gene polymorphisms.

Night shift work has been associated with an increased risk of breast cancer pointing to a role of circadian disruption. We investigated the role of circadian clock gene polymorphisms and their interaction with nightwork in breast cancer risk in a population-based case-control study in France including 1126 breast cancer cases and 1174 controls. We estimated breast cancer risk associated with each of the 577 single nucleotide polymorphisms (SNPs) in 23 circadian clock genes. We also used a gene- and pathway-based approach to investigate the overall effect on breast cancer of circadian clock gene variants that might not be detected in analyses based on individual SNPs. Interactions with nightwork were tested at the SNP, gene, and pathway levels. We found that two SNPs in RORA (rs1482057 and rs12914272) were associated with breast cancer in the whole sample and among postmenopausal women. In this subpopulation, we also reported an association with rs11932595 in CLOCK, and with CLOCK, RORA, and NPAS2 in the analyses at the gene level. Breast cancer risk in postmenopausal women was also associated with overall genetic variation in the circadian gene pathway (P=0.04), but this association was not detected in premenopausal women. There was some evidence of an interaction between PER1 and nightwork in breast cancer in the whole sample (P=0.024), although the effect was not statistically significant after correcting for multiple testing (P=0.452). Our results support the hypothesis that circadian clock gene variants modulate breast cancer risk.

Family history of cancer in children with acute leukemia, Hodgkin's lymphoma or non-Hodgkin's lymphoma: The ESCALE study (SFCE)†

The role of a family history of cancer in the etiology of childhood hematopoietic malignancies was investigated using the data from the ESCALE study. ESCALE, a population‐based case–control study, was carried out in France over the period, 2003–2004. A total of 773 cases of acute leukemia (AL), 130 of Hodgkins lymphoma (HL), 163 of non‐Hodgkins lymphoma (NHL) and 1,681 population‐based controls were included. The controls were randomly selected from the French population and were frequency matched with the cases on age and gender. Cancer history in first‐ and second‐degree relatives was reported by the mothers in a structured telephone questionnaire that was the same for the cases and controls. Odds ratios (ORs) were estimated using an unconditional regression model taking into account the stratification variables and potential confounders. A family history of cancer was associated with an increased risk of HL (OR = 1.5 [1.0–2.2]) and NHL (OR = 1.8 [1.3–2.5]), but not AL (OR = 1.0 [0.9–1.2]). The ORs were higher when at least 2 relatives had a history of cancer or when 1 case occurred before age 46 years. Only HL was significantly associated with a family history of hematopoietic malignancies (OR = 2.0 [1.0–3.8]), mainly because of a significant association with a history of HL (OR = 5.4 [1.3–22]). In conclusion, the study findings support the hypothesis of familial susceptibility to childhood lymphoma, but do not suggest familial susceptibility to childhood AL.

Birth-related characteristics, congenital malformation, maternal reproductive history and neuroblastoma: The ESCALE study (SFCE).

Since neuroblastoma occurs very early in childrens lives, it has been hypothesized that pre‐ and perinatal factors may play a role in its etiology. This study investigated the role of birth characteristics, congenital malformation and maternal reproductive history in neuroblastoma. The data used were generated by the national population‐based case–control study, ESCALE, conducted in France in 2003–2004. The mothers of 191 neuroblastoma cases and 1,681 controls, frequency‐matched by age and gender, were interviewed by telephone, using a standardized questionnaire, on several factors including pregnancy, medical history, lifestyle, childhood medical conditions and exposures. A positive association between congenital malformation and all neuroblastoma cases was observed [Odds ratio (OR) = 2.2, 95% confidence interval (95% CI): 1.1–4.5]. Congenital malformations were highly associated to neuroblastoma in children aged less than 1 year (OR = 16.8, 95% CI: 3.1–90), while no association was observed in children aged 1 year or more (OR = 1.0, 95% CI: 0.3–2.9). A negative association with a maternal history of spontaneous abortions was also found (OR = 0.6, 95% CI: 0.4–0.9). The results strongly support the hypothesis that congenital anomalies may be associated with neuroblastoma, particularly in infant (less than 1 year of age).

Identification of new genetic susceptibility Loci for breast cancer through consideration of gene-environment interactions

Genes that alter disease risk only in combination with certain environmental exposures may not be detected in genetic association analysis. By using methods accounting for gene‐environment (G × E) interaction, we aimed to identify novel genetic loci associated with breast cancer risk. Up to 34,475 cases and 34,786 controls of European ancestry from up to 23 studies in the Breast Cancer Association Consortium were included. Overall, 71,527 single nucleotide polymorphisms (SNPs), enriched for association with breast cancer, were tested for interaction with 10 environmental risk factors using three recently proposed hybrid methods and a joint test of association and interaction. Analyses were adjusted for age, study, population stratification, and confounding factors as applicable. Three SNPs in two independent loci showed statistically significant association: SNPs rs10483028 and rs2242714 in perfect linkage disequilibrium on chromosome 21 and rs12197388 in ARID1B on chromosome 6. While rs12197388 was identified using the joint test with parity and with age at menarche (P‐values = 3 × 10−07), the variants on chromosome 21 q22.12, which showed interaction with adult body mass index (BMI) in 8,891 postmenopausal women, were identified by all methods applied. SNP rs10483028 was associated with breast cancer in women with a BMI below 25 kg/m2 (OR = 1.26, 95% CI 1.15–1.38) but not in women with a BMI of 30 kg/m2 or higher (OR = 0.89, 95% CI 0.72–1.11, P for interaction = 3.2 × 10−05). Our findings confirm comparable power of the recent methods for detecting G × E interaction and the utility of using G × E interaction analyses to identify new susceptibility loci.