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1.  SETIL: Italian multicentric epidemiological case–control study on risk factors for childhood leukaemia, non hodgkin lymphoma and neuroblastoma: study population and prevalence of risk factors in Italy 
Aetiology of childhood leukaemia and childhood neoplasm is poorly understood. Information on the prevalence of risk factors in the childhood population is limited. SETIL is a population based case–control study on childhood leukaemia, conducted with two companion studies on non-Hodgkin Lymphoma (NHL) and neuroblastoma. The study relies on questionnaire interviews and 50 Hz magnetic field (ELF-MF) indoor measurements. This paper discusses the SETIL study design and includes descriptive information.
The study was carried out in 14 Italian regions (78.3% of Italian population aged 0–10). It included leukaemia, NHL and neuroblastoma cases incident in 0–10 year olds in 1998–2001, registered by the Italian Association of Paediatric Haematology and Oncology (AIEOP) (accrual over 95% of estimated incidence). Two controls for each leukaemia case were randomly sampled from the Local Health Authorities rolls, matched by gender, birthdate and residence. The same controls were used in NHL and neuroblastoma studies. Parents were interviewed at home on: physical agents (ELF-MF and ionizing radiation), chemicals (smoking, solvents, traffic, insecticides), occupation, medical and personal history of children and parents, infectious diseases, immunizations and associated factors. Occupational exposure was collected using job specific modules. ELF-MF was measured in the main rooms (spot measurement) and close to child’s bed (48 hours measurement).
The study included: 683 leukaemia cases (87% ALL, 13% AnLL), 97 NHL, 155 neuroblastomas, and 1044 controls.
ELF-MF long term measurements were obtained for 61.1% of controls and 81.6% of leukaemia cases; 8.8% of controls were exposed at over 0.1 microTesla (μT), 3.5% and 2.1% at respectively over 0.2 and 0.3 μT. 25% of controls’ fathers had smoked over 10 cigarettes/day during the year of conception, varying according to education and region. Maternal smoking was less common (71.4% did not smoke in pregnancy). Maternal passive smoking during pregnancy was reported by 31.2% of controls; the child’s passive smoking for 28.6%.
Occupational exposure to solvents was estimated in 18.3% of controls’ fathers and 7.7% of mothers. Contact with public was more frequent among mothers (36.1%) than fathers (23.4%).
SETIL represents a data source on exposure of Italian children to a broad array of potential carcinogenic factors.
Electronic supplementary material
The online version of this article (doi:10.1186/s13052-014-0103-5) contains supplementary material, which is available to authorized users.
PMCID: PMC4310183  PMID: 25539823
Leukaemia; Non hogdkin lymphoma; Neuroblastoma; Epidemiology; Risk factors
2.  A Pooled Analysis of Alcohol Consumption and Risk of Multiple Myeloma in the International Multiple Myeloma Consortium 
Recent findings suggest that alcohol consumption may reduce risk of multiple myeloma (MM).
To better understand this relationship, we conducted an analysis of six case-control studies participating in the International Multiple Myeloma Consortium (1,567 cases, 7,296 controls). Summary odds ratios (ORs) and 95% confidence intervals (CI) relating different measures of alcohol consumption and MM risk were computed by unconditional logistic regression with adjustment for age, race, and study center.
Cases were significantly less likely than controls to report ever drinking alcohol (men: OR 0.72, 95% CI 0.59-0.89, women: OR 0.81, 0.68-0.95). The inverse association with MM was stronger when comparing current to never drinkers (men: OR=0.57, 95% CI 0.45-0.72, women: OR=0.55, 95% CI 0.45-0.68), but null among former drinkers. We did not observe an exposure-response relationship with increasing alcohol frequency, duration or cumulative lifetime consumption. Additional adjustment for body mass index, education, or smoking did not affect our results; and the patterns of association were similar for each type of alcohol beverage examined.
Our study is, to our knowledge, the largest of its kind to date, and our findings suggest that alcohol consumption may be associated with reduced risk of MM.
Prospective studies, especially those conducted as pooled analyses with large sample sizes, are needed to confirm our findings and further explore whether alcohol consumption provides true biologic protection against this rare, highly fatal malignancy.
PMCID: PMC3769449  PMID: 23964064
3.  Personal Use of Hair Dye and the Risk of Certain Subtypes of Non-Hodgkin Lymphoma 
American journal of epidemiology  2008;167(11):1321-1331.
Personal use of hair dye has been inconsistently linked to risk of non-Hodgkin lymphoma (NHL), perhaps because of small samples or a lack of detailed information on personal hair-dye use in previous studies. This study included 4,461 NHL cases and 5,799 controls from the International Lymphoma Epidemiology Consortium 1988–2003. Increased risk of NHL (odds ratio (OR) = 1.3, 95% confidence interval (CI): 1.1, 1.4) associated with hair-dye use was observed among women who began using hair dye before 1980. Analyses by NHL subtype showed increased risk for follicular lymphoma (FL) and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) but not for other NHL subtypes. The increased risks of FL (OR = 1.4, 95% CI: 1.1, 1.9) and CLL/SLL (OR = 1.5, 95% CI: 1.1, 2.0) were mainly observed among women who started using hair dyes before 1980. For women who began using hair dye in 1980 or afterward, increased FL risk was limited to users of dark-colored dyes (OR = 1.5, 95% CI: 1.1, 2.0). These results indicate that personal hair-dye use may play a role in risks of FL and CLL/SLL in women who started use before 1980 and that increased risk of FL among women who started use during or after 1980 cannot be excluded.
PMCID: PMC4025953  PMID: 18408225
case-control studies; hair dyes; lymphoma; non-Hodgkin
4.  Hepatitis C and Non-Hodgkin Lymphoma Among 4784 Cases and 6269 Controls From the International Lymphoma Epidemiology Consortium 
Background & Aims
Increasing evidence points towards a role of hepatitis C virus (HCV) infection in causing malignant lymphomas. We pooled case-control study data to provide robust estimates of the risk of non-Hodgkin’s lymphoma (NHL) subtypes after HCV infection.
The analysis included 7 member studies from the International Lymphoma Epidemiology Consortium (InterLymph) based in Europe, North America, and Australia. Adult cases of NHL (n = 4784) were diagnosed between 1988 and 2004 and controls (n = 6269) were matched by age, sex, and study center. All studies used third-generation enzyme-linked immunosorbent assays to test for antibodies against HCV in serum samples. Participants who were human immunodeficiency virus positive or were organ-transplant recipients were excluded.
HCV infection was detected in 172 NHL cases (3.60%) and in 169 (2.70%) controls (odds ratio [OR], 1.78; 95% confidence interval [CI], 1.40–2.25). In subtype-specific analyses, HCV prevalence was associated with marginal zone lymphoma (OR, 2.47; 95% CI, 1.44–4.23), diffuse large B-cell lymphoma (OR, 2.24; 95% CI, 1.68–2.99), and lymphoplasmacytic lymphoma (OR, 2.57; 95% CI, 1.14–5.79). Notably, risk estimates were not increased for follicular lymphoma (OR, 1.02; 95% CI, 0.65–1.60).
These results confirm the association between HCV infection and NHL and specific B-NHL subtypes (diffuse large B-cell lymphoma, marginal zone lymphoma, and lymphoplasmacytic lymphoma).
PMCID: PMC3962672  PMID: 18387498
5.  Non-Hodgkin lymphoma and Obesity: a pooled analysis from the InterLymph consortium 
Nutritional status is known to alter immune function, a suspected risk factor for non-Hodgkin lymphoma (NHL). To investigate whether long-term over, or under, nutrition is associated with NHL self-reported anthropometric data on weight and height from over 10000 cases of NHL and 16000 controls were pooled across 18 case-control studies identified through the International Lymphoma Epidemiology Consortium. Study-specific odds ratios (OR) were estimated using logistic regression and combined using a random-effects model. Severe obesity, defined as BMI of 40 kg m−2 or more, was not associated with NHL overall (pooled OR=1.00, 95% confidence interval (CI) 0.70–1.41) or the majority of NHL subtypes. An excess was however observed for diffuse large B-cell lymphoma (pooled OR=1.80, 95% CI 1.24–2.62), although not all study-specific ORs were raised. Among the overweight (BMI 25–29.9 kg m−2) and obese (BMI 30–39.9 kg m−2), associations were elevated in some studies and decreased in others, while no association was observed among the underweight (BMI<18.5 kg m−2). There was little suggestion of increasing ORs for NHL or its subtypes with every 5 kg m−2 rise in BMI above 18.5 kg m−2. BMI components height and weight were also examined, and the tallest men, but not women, were at marginally increased risk (pooled OR=1.19, 95% CI 1.06–1.34). In summary, whilst we conclude that there is no evidence to support the hypothesis that obesity is a determinant of all types of NHL combined, the association between severe obesity and diffuse large B-cell lymphoma may warrant further investigation.
PMCID: PMC3928289  PMID: 18167059
non-Hodgkin lymphoma; lymphoma; body mass index; weight; height; epidemiology
6.  Genome-wide Association Study Identifies Multiple Risk Loci for Chronic Lymphocytic Leukemia 
Berndt, Sonja I. | Skibola, Christine F. | Joseph, Vijai | Camp, Nicola J. | Nieters, Alexandra | Wang, Zhaoming | Cozen, Wendy | Monnereau, Alain | Wang, Sophia S. | Kelly, Rachel S. | Lan, Qing | Teras, Lauren R. | Chatterjee, Nilanjan | Chung, Charles C. | Yeager, Meredith | Brooks-Wilson, Angela R. | Hartge, Patricia | Purdue, Mark P. | Birmann, Brenda M. | Armstrong, Bruce K. | Cocco, Pierluigi | Zhang, Yawei | Severi, Gianluca | Zeleniuch-Jacquotte, Anne | Lawrence, Charles | Burdette, Laurie | Yuenger, Jeffrey | Hutchinson, Amy | Jacobs, Kevin B. | Call, Timothy G. | Shanafelt, Tait D. | Novak, Anne J. | Kay, Neil E. | Liebow, Mark | Wang, Alice H. | Smedby, Karin E | Adami, Hans-Olov | Melbye, Mads | Glimelius, Bengt | Chang, Ellen T. | Glenn, Martha | Curtin, Karen | Cannon-Albright, Lisa A. | Jones, Brandt | Diver, W. Ryan | Link, Brian K. | Weiner, George J. | Conde, Lucia | Bracci, Paige M. | Riby, Jacques | Holly, Elizabeth A. | Smith, Martyn T. | Jackson, Rebecca D. | Tinker, Lesley F. | Benavente, Yolanda | Becker, Nikolaus | Boffetta, Paolo | Brennan, Paul | Foretova, Lenka | Maynadie, Marc | McKay, James | Staines, Anthony | Rabe, Kari G. | Achenbach, Sara J. | Vachon, Celine M. | Goldin, Lynn R | Strom, Sara S. | Lanasa, Mark C. | Spector, Logan G. | Leis, Jose F. | Cunningham, Julie M. | Weinberg, J. Brice | Morrison, Vicki A. | Caporaso, Neil E. | Norman, Aaron D. | Linet, Martha S. | De Roos, Anneclaire J. | Morton, Lindsay M. | Severson, Richard K. | Riboli, Elio | Vineis, Paolo | Kaaks, Rudolph | Trichopoulos, Dimitrios | Masala, Giovanna | Weiderpass, Elisabete | Chirlaque, María-Dolores | Vermeulen, Roel C H | Travis, Ruth C. | Giles, Graham G. | Albanes, Demetrius | Virtamo, Jarmo | Weinstein, Stephanie | Clavel, Jacqueline | Zheng, Tongzhang | Holford, Theodore R | Offit, Kenneth | Zelenetz, Andrew | Klein, Robert J. | Spinelli, John J. | Bertrand, Kimberly A. | Laden, Francine | Giovannucci, Edward | Kraft, Peter | Kricker, Anne | Turner, Jenny | Vajdic, Claire M. | Ennas, Maria Grazia | Ferri, Giovanni M. | Miligi, Lucia | Liang, Liming | Sampson, Joshua | Crouch, Simon | Park, Ju-hyun | North, Kari E. | Cox, Angela | Snowden, John A. | Wright, Josh | Carracedo, Angel | Lopez-Otin, Carlos | Bea, Silvia | Salaverria, Itziar | Martin, David | Campo, Elias | Fraumeni, Joseph F. | de Sanjose, Silvia | Hjalgrim, Henrik | Cerhan, James R. | Chanock, Stephen J. | Rothman, Nathaniel | Slager, Susan L.
Nature genetics  2013;45(8):868-876.
PMCID: PMC3729927  PMID: 23770605
7.  A functional TNFRSF5 polymorphism and risk of non-Hodgkin lymphoma, a pooled analysis 
Interaction between CD40 and its ligand, CD154, has a key function in immune regulation. Recent experimental data support a role of deregulated CD40 signalling in lymphomagenesis. Data from earlier studies that are part of this pooling study implicate a functional polymorphism (−1C>T, rs1883832) in the TNFRSF5 gene encoding CD40 in the etiology of follicular lymphoma. Here, the association of this variant with non-Hodgkin lymphoma (NHL) risk was replicated in a European multicenter study of 855 NHL cases and 1,206 controls. In the combined analysis of 2,617 cases and 3,605 controls, carrying the TT genotype was associated with an increased risk for all NHL (OR = 1.4; p for linear trend = 0.00009), diffuse large B-cell lymphoma (OR = 1.6; p for linear trend = 0.002) and follicular lymphoma (OR = 1.6; p for linear trend = 0.001). These data suggest a possible role of this functional polymorphism in lymphomas originating within the germinal center.
PMCID: PMC3876741  PMID: 20473910
lymphoma; TNFRSF5; CD40; polymorphism; epidemiology
8.  Self-reported history of infections and the risk of non-Hodgkin lymphoma: an InterLymph pooled analysis 
We performed a pooled analysis of data on self-reported history of infections in relation to the risk of non-Hodgkin lymphoma (NHL) from 17 case-control studies that included 12,585 cases and 15,416 controls aged 16–96 years at recruitment. Pooled odds ratios (OR) and 95% confidence intervals (95% CI) were estimated in two-stage random-effect or joint fixed-effect models, adjusting for age, sex and study centre. Data from the two years prior to diagnosis (or date of interview for controls) were excluded. A self-reported history of infectious mononucleosis (IM) was associated with an excess risk of NHL (OR=1.26, 95% CI=1.01–1.57 based on data from 16 studies); study-specific results indicate significant (I2=51%, p=0.01) heterogeneity. A self-reported history of measles or whooping cough was associated with an approximate 15% reduction in risk. History of other infection was not associated with NHL. We find little clear evidence of an association between NHL risk and infection although the limitations of data based on self-reported medical history (particularly of childhood illness reported by older people) are well recognised.
PMCID: PMC3406230  PMID: 22266776
9.  A comprehensive study of polymorphisms in the ABCB1, ABCC2, ABCG2, NR1I2 genes and lymphoma risk 
Owing to their role in controlling the efflux of toxic compounds, transporters are central players in the process of detoxification and elimination of xenobiotics, which in turn is related to cancer risk. Among these transporters, ATP-binding cassette B1/multidrug resistance 1 (ABCB1/MDR1), ABCC2/multidrug resistance protein 2 (MRP2), and ABCG2/breast cancer resistance protein (BCRP) affect susceptibility to many hematopoietic malignancies. The maintenance of regulated expression of these transporters is governed through the activation of intracellular “xenosensors” like the nuclear receptor 1I2/pregnane X receptor (NR1I2/PXR). SNPs in genes encoding these regulators have also been implicated in the risk of several cancers. Using a tagging approach, we tested the hypothesis that common polymorphisms in the transporter genes ABCB1, ABCC2, ABCG2, and the regulator gene NR1I2 could be implicated in lymphoma risk. We selected 68 SNPs in the 4 genes, and we genotyped them in 1,481 lymphoma cases and 1,491 controls of the European cases-control study (EpiLymph) using the Illumina™ GoldenGate assay technology.Carriers of the SNP rs6857600 minor allele in ABCG2, was associated with a decrease in risk of B-cell lymphoma (B-NHL) overall (p<0.001). Furthermore, a decreased risk of chronic lymphocytic leukemia (CLL) was associated with the ABCG2 rs2231142 variant (p=0.0004), which could be replicated in an independent population. These results suggest a role for this gene in B-NHL susceptibility, especially for CLL.
PMCID: PMC3432449  PMID: 21918980
Lymphoma; multidrug resistance 1 (MDR1); multidrug resistance protein 2 (MRP2); breast cancer resistance protein (BCRP); pregnane X receptor (PXR)
10.  Exposure to benzene and childhood leukaemia: a pilot case-control study 
BMJ Open  2013;3(2):e002275.
Main purpose To evaluate the feasibility of a measurement-based assessment of benzene exposure in case-control studies of paediatric cancer; Additional aims To identify the sources of exposure variability; to assess the performance of two benzene biomarkers; to verify the occurrence of participation bias; to check whether exposures to benzene and to 50 Hz magnetic fields were correlated, and might exert reciprocal confounding effects.
Pilot case-control study of childhood leukaemia and exposure to benzene assessed by repeated seasonal weekly measurements in breathing zone air samples and outside the children's dwellings, with concurrent determinations of cotinine, t-t-muconic acid (MA) and sulfo-phenylmercapturic acid (S-PMA) in urine.
108 cases and 194 controls were eligible for inclusion.
Full-participation was obtained from 46 cases and 60 controls, with low dropout rates before four repeats (11% and 17%); an additional 23 cases and 80 controls allowed the collection of outdoor air samples only. The average benzene concentration in personal and outdoor air samples was 3 μg/m3 (SD 1.45) and 2.7 μg/m3 (SD 1.41), respectively. Personal exposure was strongly influenced by outdoor benzene concentrations, higher in the cold seasons than in warm seasons, and not affected by gender, age, area of residence or caseness. Urinary excretion of S-PMA and personal benzene exposure were well correlated. Outdoor benzene levels were lower among participant controls compared with non-participants, but did not differ between participant and non-participant cases; the direction of the bias was found to depend on the cut-point chosen to distinguish exposed and unexposed. Exposures to benzene and extremely low-frequency magnetic fields were positively correlated.
Repeated individual measurements are needed to account for the seasonal variability in benzene exposure, and they have the additional advantage of increasing the study power. Measurement-based assessment of benzene exposure in studies of childhood leukaemia appears feasible, although it is financially and logistically demanding.
PMCID: PMC3586103  PMID: 23444447
11.  Genome-Wide Association Study of Classical Hodgkin Lymphoma and Epstein–Barr Virus Status–Defined Subgroups 
Accumulating evidence suggests that risk factors for classical Hodgkin lymphoma (cHL) differ by tumor Epstein–Barr virus (EBV) status. This potential etiological heterogeneity is not recognized in current disease classification.
We conducted a genome-wide association study of 1200 cHL patients and 6417 control subjects, with validation in an independent replication series, to identify common genetic variants associated with total cHL and subtypes defined by tumor EBV status. Multiple logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) assuming a log-additive genetic model for the variants. All statistical tests were two-sided.
Two novel loci associated with total cHL irrespective of EBV status were identified in the major histocompatibility complex region; one resides adjacent to MICB (rs2248462: OR = 0.61, 95% CI = 0.53 to 0.69, P = 1.3 × 10−13) and the other at HLA-DRA (rs2395185: OR = 0.56, 95% CI = 0.50 to 0.62, P = 8.3 × 10−25) with both results confirmed in an independent replication series. Consistent with previous reports, associations were found between EBV-positive cHL and genetic variants within the class I region (rs2734986, HLA-A: OR = 2.45, 95% CI = 2.00 to 3.00, P = 1.2 × 10−15; rs6904029, HCG9: OR = 0.46, 95% CI = 0.36 to 0.59, P = 5.5 × 10−10) and between EBV-negative cHL and rs6903608 within the class II region (rs6903608, HLA-DRA: OR = 2.08, 95% CI = 1.84 to 2.35, P = 6.1 × 10−31). The association between rs6903608 and EBV-negative cHL was confined to the nodular sclerosis histological subtype. Evidence for an association between EBV-negative cHL and rs20541 (5q31, IL13: OR = 1.53, 95% CI = 1.32 to 1.76, P = 5.4 x 10−9), a variant previously linked to psoriasis and asthma, was observed; however, the evidence for replication was less clear. Notably, one additional psoriasis-associated variant, rs27524 (5q15, ERAP1), showed evidence of an association with cHL in the genome-wide association study (OR = 1.21, 95% CI = 1.10 to 1.33, P = 1.5 × 10−4) and replication series (P = .03).
Overall, these results provide strong evidence that EBV status is an etiologically important classification of cHL and also suggest that some components of the pathological process are common to both EBV-positive and EBV-negative patients.
PMCID: PMC3274508  PMID: 22286212
12.  Correcting a fundamental error in greenhouse gas accounting related to bioenergy 
Energy Policy  2012;45-222(5):18-23.
Many international policies encourage a switch from fossil fuels to bioenergy based on the premise that its use would not result in carbon accumulation in the atmosphere. Frequently cited bioenergy goals would at least double the present global human use of plant material, the production of which already requires the dedication of roughly 75% of vegetated lands and more than 70% of water withdrawals. However, burning biomass for energy provision increases the amount of carbon in the air just like burning coal, oil or gas if harvesting the biomass decreases the amount of carbon stored in plants and soils, or reduces carbon sequestration. Neglecting this fact results in an accounting error that could be corrected by considering that only the use of ‘additional biomass’ – biomass from additional plant growth or biomass that would decompose rapidly if not used for bioenergy – can reduce carbon emissions. Failure to correct this accounting flaw will likely have substantial adverse consequences. The article presents recommendations for correcting greenhouse gas accounts related to bioenergy.
PMCID: PMC3617913  PMID: 23576835
Bioenergy; Greenhouse gas emissions; Greenhouse gas accounting
13.  Increased Mitochondrial DNA Copy Number in Occupations Associated with Low-Dose Benzene Exposure 
Environmental Health Perspectives  2011;120(2):210-215.
Background: Benzene is an established leukemogen at high exposure levels. Although low-level benzene exposure is widespread and may induce oxidative damage, no mechanistic biomarkers are available to detect biological dysfunction at low doses.
Objectives: Our goals were to determine in a large multicenter cross-sectional study whether low-level benzene is associated with increased blood mitochondrial DNA copy number (mtDNAcn, a biological oxidative response to mitochondrial DNA damage and dysfunction) and to explore potential links between mtDNAcn and leukemia-related epigenetic markers.
Methods: We measured blood relative mtDNAcn by real-time polymerase chain reaction in 341 individuals selected from various occupational groups with low-level benzene exposures (> 100 times lower than the Occupational Safety and Health Administration/European Union standards) and 178 referents from three Italian cities (Genoa, Milan, Cagliari).
Results: In each city, benzene-exposed participants showed higher mtDNAcn than referents: mtDNAcn was 0.90 relative units in Genoa bus drivers and 0.75 in referents (p = 0.019); 0.90 in Milan gas station attendants, 1.10 in police officers, and 0.75 in referents (p-trend = 0.008); 1.63 in Cagliari petrochemical plant workers, 1.25 in referents close to the plant, and 0.90 in referents farther from the plant (p-trend = 0.046). Using covariate-adjusted regression models, we estimated that an interquartile range increase in personal airborne benzene was associated with percent increases in mtDNAcn equal to 10.5% in Genoa (p = 0.014), 8.2% (p = 0.008) in Milan, 7.5% in Cagliari (p = 0.22), and 10.3% in all cities combined (p < 0.001). Using methylation data available for the Milan participants, we found that mtDNAcn was associated with LINE-1 hypomethylation (–2.41%; p = 0.007) and p15 hypermethylation (+15.95%, p = 0.008).
Conclusions: Blood MtDNAcn was increased in persons exposed to low benzene levels, potentially reflecting mitochondrial DNA damage and dysfunction.
PMCID: PMC3279451  PMID: 22005026
benzene; biomarkers; low exposures; methylation; mitochondrial DNA copy number
14.  Birth Order and Risk of Non-Hodgkin Lymphoma—True Association or Bias? 
American Journal of Epidemiology  2010;172(6):621-630.
There is inconsistent evidence that increasing birth order may be associated with risk of non-Hodgkin lymphoma (NHL). The authors examined the association between birth order and related variables and NHL risk in a pooled analysis (1983–2005) of 13,535 cases and 16,427 controls from 18 case-control studies within the International Lymphoma Epidemiology Consortium (InterLymph). Overall, the authors found no significant association between increasing birth order and risk of NHL (P-trend = 0.082) and significant heterogeneity. However, a significant association was present for a number of B- and T-cell NHL subtypes. There was considerable variation in the study-specific risks which was partly explained by study design and participant characteristics. In particular, a significant positive association was present in population-based studies, which had lower response rates in cases and controls, but not in hospital-based studies. A significant positive association was present in higher-socioeconomic-status (SES) participants only. Results were very similar for the related variable of sibship size. The known correlation of high birth order with low SES suggests that selection bias related to SES may be responsible for the association between birth order and NHL.
PMCID: PMC2950815  PMID: 20720098
birth order; case-control studies; lymphoma, non-Hodgkin; selection bias; social class
15.  Genome-wide association study of follicular lymphoma identifies a risk locus at 6p21.32 
Nature genetics  2010;42(8):661-664.
To identify susceptibility loci for non-Hodgkin lymphoma (NHL) subtypes, we conducted a three-stage genome-wide association study. We identified two variants associated with follicular lymphoma (FL) in 1,465 FL cases/6,958 controls at 6p21.32 (rs10484561, rs7755224, r2=1.0; combined p-values=1.12×10-29, 2.00×10-19), providing further support that MHC genetic variation influences FL susceptibility. Confirmatory evidence of a previously reported association was also found between chronic lymphocytic leukemia/small lymphocytic lymphoma and rs735665 (combined p-value=4.24×10-9).
PMCID: PMC2913472  PMID: 20639881
16.  Tumor Necrosis Factor (TNF) and Lymphotoxin-α (LTA) Polymorphisms and Risk of Non-Hodgkin Lymphoma in the InterLymph Consortium 
American Journal of Epidemiology  2010;171(3):267-276.
In an International Lymphoma Epidemiology Consortium pooled analysis, polymorphisms in 2 immune-system-related genes, tumor necrosis factor (TNF) and interleukin-10 (IL10), were associated with non-Hodgkin lymphoma (NHL) risk. Here, 8,847 participants were added to previous data (patients diagnosed from 1989 to 2005 in 14 case-control studies; 7,999 cases, 8,452 controls) for testing of polymorphisms in the TNF –308G>A (rs1800629), lymphotoxin-α (LTA) 252A>G (rs909253), IL10 –3575T>A (rs1800890, rs1800896), and nucleotide-binding oligomerization domain containing 2 (NOD2) 3020insC (rs2066847) genes. Odds ratios were estimated for non-Hispanic whites and several ethnic subgroups using 2-sided tests. Consistent with previous findings, odds ratios were increased for “new” participant TNF –308A carriers (NHL: per-allele odds ratio (ORallelic) = 1.10, Ptrend = 0.001; diffuse large B-cell lymphoma (DLBCL): ORallelic = 1.23, Ptrend = 0.004). In the combined population, odds ratios were increased for TNF –308A carriers (NHL: ORallelic = 1.13, Ptrend = 0.0001; DLBCL: ORallelic = 1.25, Ptrend = 3.7 × 10−6; marginal zone lymphoma: ORallelic = 1.35, Ptrend = 0.004) and LTA 252G carriers (DLBCL: ORallelic = 1.12, Ptrend = 0.006; mycosis fungoides: ORallelic = 1.44, Ptrend = 0.015). The LTA 252A>G/TNF –308G>A haplotype containing the LTA/TNF variant alleles was strongly associated with DLBCL (P = 2.9 × 10−8). Results suggested associations between IL10 –3575T>A and DLBCL (Ptrend = 0.02) and IL10 –1082A>G and mantle cell lymphoma (Ptrend = 0.04). These findings strengthen previous results for DLBCL and the LTA 252A>G/TNF –308A locus and provide robust evidence that these TNF/LTA gene variants, or others in linkage disequilibrium, are involved in NHL etiology.
PMCID: PMC2842204  PMID: 20047977
lymphoma; lymphoma, non-Hodgkin; lymphotoxin-alpha; meta-analysis; polymorphism, genetic; polymorphism, single nucleotide; tumor necrosis factor-alpha
17.  Atopic disease and risk of non-Hodgkin lymphoma: an InterLymph pooled analysis 
Cancer research  2009;69(16):6482-6489.
We performed a pooled analysis of data on atopic disease and risk of non-Hodgkin lymphoma (NHL) from 13 case-control studies, including13,535 NHL cases and 16,388 controls. Self-reported atopic diseases diagnosed two or more years before NHL diagnosis (cases) or interview (controls) were analyzed. Pooled odds ratios (OR) and 95% confidence intervals were computed in two-stage random-effects or joint fixed-effects models, adjusted for age, sex, and study center. When modeled individually, lifetime history of asthma, hay fever, a specific allergy (excluding hay fever, asthma and eczema), and food allergy were associated with a significant reduction in NHL risk, and there was no association for eczema. When each atopic condition was included in the same model, reduced NHL risk was only associated with history of allergy (OR 0.80, 95% CI 0.68–0.94), and reduced B-cell NHL risk was associated with history of hay fever (OR 0.85, 95% CI 0.77–0.95) and allergy (OR 0.84, 95% CI 0.76–0.93). Significant reductions in B-cell NHL risk were also observed in individuals who were likely to be truly or highly atopic - those with hay fever, allergy or asthma and at least one other atopic condition over their lifetime. The inverse associations were consistent for the diffuse large B-cell and follicular subtypes. Eczema was positively associated with lymphomas of the skin; misdiagnosis of lymphoma as eczema is likely, but progression of eczema to cutaneous lymphoma cannot be excluded. This pooled study demonstrates evidence of a modest but consistent reduction in the risk of B-cell NHL associated with atopy.
PMCID: PMC2758272  PMID: 19654312
non-Hodgkin lymphoma; atopy; case-control; pooled analysis; risk
18.  Causes of death among lead smelters in relation to the glucose‐6‐phosphate dehydrogenase polymorphism 
To assess, by updating a follow‐up mortality study of a lead smelters cohort in Sardinia, Italy, the adverse health effects following occupational lead exposure in relation to the glucose‐6‐phosphate dehydrogenase (G6PD) polymorphism.
The 1973–2003 mortality of 1017 male lead smelters were followed‐up, divided into two subcohorts according to the G6PD phenotype: whether G6PD deficient (G6PD−) or wild‐type (wtG6PD). Deaths observed in the overall cohort and the two subcohorts were compared with those expected, on the basis of the age‐, sex‐ and calendar year‐specific mortality in the general male population of the island. Directly standardised mortality rates (sr) in the two subcohorts were also compared.
Cardiovascular mortality was strongly reduced among production and maintenance workers, which is most related to the healthy worker effect. However, the sr for cardiovascular diseases was substantially lower among the G6PD− subcohort (5.0×10−4) than among the wtG6PD subcohort (33.6×10−4; χ2 = 1.10; p = NS). Neoplasms of the haemopoietic system exceeded the expectation in the G6PD− subcohort (SMR = 388; 95% CI 111 to 1108). No other cancer sites showed any excess in the overall cohort or in the two subcohorts. No death from haemolytic anaemia occurred in the G6PD− subcohort.
With due consideration of the limited statistical power of our study, previous results suggesting that in workplaces where exposure is under careful control, expressing the G6PD− phenotype does not convey increased susceptibility to lead toxicity are confirmed. The observed excess risk of haematopoietic malignancies seems to have most likely resulted from chance.
PMCID: PMC2078505  PMID: 17182638
19.  Epidemiology, Public Health, and the Rhetoric of False Positives 
Environmental Health Perspectives  2009;117(12):1809-1813.
As an observational science, epidemiology is regarded by some researchers as inherently flawed and open to false results. In a recent paper, Boffetta et al. [Boffetta P, McLaughlin JK, LaVecchia C, Tarone RE, Lipworth L, Blot WJ. False-positive results in cancer epidemiology: a plea for epistemological modesty. J Natl Cancer Inst 100:988–995 (2008)] argued that “epidemiology is particularly prone to the generation of false-positive results.” They also said “the tendency to emphasize and over-interpret what appear to be new findings is commonplace, perhaps in part because of a belief that the findings provide information that may ultimately improve public health” and that “this tendency to hype new findings increases the likelihood of downplaying inconsistencies within the data or any lack of concordance with other sources of evidence.” The authors supported these serious charges against epidemiology and epidemiologists with few examples. Although we acknowledge that false positives do occur, we view the position of Boffetta and colleagues on false positives as unbalanced and potentially harmful to public health.
We aim to provide a more balanced evaluation of epidemiology and its contribution to public health discourse.
Boffetta and colleagues ignore the fact that false negatives may arise from the very processes that they tout as generating false-positive results. We further disagree with their proposition that false-positive results from a single study will lead to faulty decision making in matters of public health importance. In practice, such public health evaluations are based on all the data available from all relevant disciplines and never to our knowledge on a single study.
The lack of balance by Boffetta and colleagues in their evaluation of the impact of false-positive findings on epidemiology, the charge that “methodological vigilance is often absent” in epidemiologists’ interpretation of their own results, and the false characterization of how epidemiologic findings are used in societal decision making all undermine a major source of information regarding disease risks. We reaffirm the importance of epidemiologic evidence as a critical component of the foundation of public health protection.
PMCID: PMC2799452  PMID: 20049197
epidemiologic methods; false negatives; false positives; hyped findings
20.  Cancer Mortality among Men Occupationally Exposed to Dichlorodiphenyltrichloroethane 
Cancer research  2005;65(20):9588-9594.
Several studies have evaluated cancer risk associated with occupational and environmental exposure to dichlorodiphenyltrichloroethane (DDT). Results are mixed. To further inquire into human carcinogenicity of DDT, we conducted a mortality follow-up study of 4,552 male workers, exposed to DDT during antimalarial operations in Sardinia, Italy, conducted in 1946 to 1950. Detailed information on DDT use during the operations provided the opportunity to develop individual estimates of average and cumulative exposure. Mortality of the cohort was first compared with that of the Sardinian population. Overall mortality in the cohort was about as expected, but there was a deficit for death from cardiovascular disease and a slight excess for nonmalignant respiratory diseases and lymphatic cancer among the unexposed subcohort. For internal comparisons, we used Poisson regression analysis to calculate relative risks of selected malignant and nonmalignant diseases with the unexposed subcohort as the reference. Cancer mortality was decreased among DDT-exposed workers, mainly due to a reduction in lung cancer deaths. Birth outside from the study area was a strong predictor of mortality from leukemia. Mortality from stomach cancer increased up to 2-fold in the highest quartile of cumulative exposure (relative risk, 2.0; 95% confidence interval, 0.9–4.4), but no exposure-response trend was observed. Risks of liver cancer, pancreatic cancer, and leukemia were not elevated among DDT-exposed workers. No effect of latency on risk estimates was observed over the 45 years of follow-up and within selected time windows. Adjusting risks by possible exposure to chlordane in the second part of the antimalarial operations did not change the results. In conclusion, we found little evidence for a link between occupational exposure to DDT and mortality from any of the cancers previously suggested to be associated.
PMCID: PMC1403737  PMID: 16230425

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