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1.  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.
Methods
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.
Results
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).
Conclusions
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).
doi:10.1016/j.cgh.2008.02.011
PMCID: PMC3962672  PMID: 18387498
2.  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.
doi:10.1002/ijc.27438
PMCID: PMC3406230  PMID: 22266776
3.  Non-Hodgkin Lymphoma Risk and Variants in Genes Controlling Lymphocyte Development 
PLoS ONE  2013;8(9):e75170.
Non-Hodgkin lymphomas (NHL) are a heterogeneous group of solid tumours of lymphoid cell origin. Three important aspects of lymphocyte development include immunity and inflammation, DNA repair, and programmed cell death. We have used a previously established case-control study of NHL to ask whether genetic variation in genes involved in these three important processes influences risk of this cancer. 118 genes in these three categories were tagged with single nucleotide polymorphisms (SNPs), which were tested for association with NHL and its subtypes. The main analysis used logistic regression (additive model) to estimate odds ratios in European-ancestry cases and controls. 599 SNPs and 1116 samples (569 cases and 547 controls) passed quality control measures and were included in analyses. Following multiple-testing correction, one SNP in MSH3, a mismatch repair gene, showed an association with diffuse large B-cell lymphoma (OR: 1.91; 95% CI: 1.41–2.59; uncorrected p = 0.00003; corrected p = 0.010). This association was not replicated in an independent European-ancestry sample set of 251 diffuse large B-cell lymphoma cases and 737 controls, indicating this result was likely a false positive. It is likely that moderate sample size, inter-subtype and other genetic heterogeneity, and small true effect sizes account for the lack of replicable findings.
doi:10.1371/journal.pone.0075170
PMCID: PMC3787098  PMID: 24098683
4.  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.
doi:10.1002/ijc.23344
PMCID: PMC3928289  PMID: 18167059
non-Hodgkin lymphoma; lymphoma; body mass index; weight; height; epidemiology
5.  Exposures to multiple pesticides and the risk of Hodgkin lymphoma in Canadian men 
Cancer Causes & Control  2013;24:1661-1673.
Purpose
To determine the risk of Hodgkin lymphoma (HL) associated with exposures to multiple pesticides grouped by various classes, including carcinogenic classifications.
Methods
Data collected in the Cross-Canada Study of Pesticides and Health, a population-based incident case–control study in six provinces conducted between 1991 and 1994, were analyzed using unconditional logistic regression. Cases (n = 316) were identified through provincial cancer registries and hospital records. Controls (n = 1,506) were frequency-matched to cases by age (±2 years) within each province and were identified through provincial health records, telephone listings, or voter lists. The Cochran–Armitage test was used to check for trends within pesticide classes.
Results
Overall, there was an increase in the risk of HL among all subjects who reported use of five or more insecticides (OR 1.88, 95 % CI 0.92–3.87) and among subjects younger than 40 who reported use of two acetylcholinesterase inhibitors (OR 3.16, 95 % CI 1.02–9.29). There was an elevated odds ratio associated with reported use of three or more probably carcinogenic pesticides (OR 2.47, 95 % CI 1.06–5.75), but no increase in risk for use of possibly carcinogenic pesticides. The risk of HL from reported use of fungicides or any pesticides was greater for cases diagnosed before age 40 than for cases diagnosed at or after age 40. When analyses excluded proxy respondents, OR estimates strengthened in some circumstances.
Conclusions
This study found associations between HL and fungicides, insecticides, specifically acetylcholinesterase inhibitors, and pesticides previously identified as probable human carcinogens. These associations should be further evaluated, specifically in relation to age at diagnosis.
doi:10.1007/s10552-013-0240-y
PMCID: PMC3734598  PMID: 23756639
Hodgkin disease; Pesticides; Age; Case–control study; Population-based
6.  Mortality among British Columbians testing for hepatitis C antibody 
BMC Public Health  2013;13:291.
Background
Hepatitis C virus (HCV) infection is a major preventable and treatable cause of morbidity and mortality. The ability to link population based centralized laboratory HCV testing data with administrative databases provided a unique opportunity to compare mortality between HCV seronegative and seropositive individuals. Through the use of laboratory testing patterns and results, the objective of this study was to differentiate the viral effects of mortality due to HCV infection from risk behaviours/activities that are associated with acquisition of HCV infection.
Methods
Serological testing data from the British Columbia (BC) Centre for Disease Control Public Health Microbiology and Reference Laboratory from 1992–2004 were linked to the BC Vital Statistics Agency death registry. Four groups of HCV testers were defined by their HCV antibody (anti-HCV) testing patterns: single non-reactive (SNR); serial multiple tested non-reactive (MNR); reactive at initial testing (REAC); and seroconverter (SERO) (previously seronegative followed by reactive, a marker for incident infection). Standardized mortality ratios (SMRs) were calculated to compare the relative risk of all cause and disease specific mortality to that of the BC population for each serological group. Time dependent Cox proportional hazard regression was used to compare hazard ratios (HRs) among HCV serological groups.
Results
All anti-HCV testers had higher SMRs than the BC population. Referent to the SNR group, the REAC group had higher risks for liver (HR: 9.62; 95% CI=8.55-10.87) and drug related mortality (HR: 13.70; 95% CI=11.76-16.13). Compared to the REAC group, the SERO group had a lower risk for liver (HR: 0.53; 95% CI=0.24-0.99), but a higher risk for drug related mortality (HR: 1.54; 95% CI=1.12-2.05).
Conclusions
These findings confirm that individuals who test anti-HCV positive have increased mortality related to progressive liver disease, and that a substantial proportion of the mortality is attributable to drug use and risk behaviours/activities associated with HCV acquisition. Mortality reduction in HCV infected individuals will require comprehensive prevention programming to reduce the harms due to behaviours/activities which relate to HCV acquisition, as well as HCV treatment to prevent progression of chronic liver disease.
doi:10.1186/1471-2458-13-291
PMCID: PMC3626540  PMID: 23547940
Hepatitis C virus; Mortality; Chronic hepatitis; Injection drug use; Data linkage
7.  Risk of Late Mortality and Second Malignant Neoplasms among 5-Year Survivors of Young Adult Cancer: A Report of the Childhood, Adolescent, and Young Adult Cancer Survivors Research Program 
Journal of Cancer Epidemiology  2012;2012:103032.
We conducted a population-based retrospective study to assess the long-term risks of overall and cause-specific mortality and second malignant neoplasm (SMN) among survivors of young adult cancer compared to the risk in British Columbia (BC) population and to evaluate the effects of demographic and clinical factors on risk. 1248 5-year survivors of young adult cancer diagnosed 1970–1995 between 20 and 24 years of age were identified from the BC Cancer Registry and followed to the end of 2007. Standardized mortality ratios (SMRs) and standardized incidence ratios (SIRs) were calculated. The Cox proportional hazards model was used to estimate the effects of different demographic and disease-related characteristics on the risk of death and SMN. A total of 138 deaths and 62 SMNs were observed during follow-up. The overall SMR was 5.9 (95% CI 4.9–6.9) and the absolute excess risk was 5.3 per 1,000 person-years. The overall SIR was 3.0 (95% CI 2.3–3.8). Treatment with radiation resulted in increased risks of death and SMN. These observed increased risks emphasize the importance of prevention, surveillance, and treatment of late effects in survivors of young adult cancers.
doi:10.1155/2012/103032
PMCID: PMC3447326  PMID: 23008713
8.  Comparison of two indices of exposure to polycyclic aromatic hydrocarbons in a retrospective aluminium smelter cohort 
Background
The association between coal tar‐derived substances, a complex mixture of polycyclic aromatic hydrocarbons, and cancer is well established. However, the specific aetiological agents are unknown.
Objective
To compare the dose–response relationships for two common measures of coal tar‐derived substances, benzene‐soluble material (BSM) and benzo(a)pyrene (BaP), and to evaluate which among these is more strongly related to the health outcomes.
Methods
The study population consisted of 6423 men with ⩾3 years of work experience at an aluminium smelter (1954–97). Three health outcomes identified from national mortality and cancer databases were evaluated: incidence of bladder cancer (n = 90), incidence of lung cancer (n = 147) and mortality due to acute myocardial infarction (AMI, n = 184). The shape, magnitude and precision of the dose–response relationships and cumulative exposure levels for BSM and BaP were evaluated. Two model structures were assessed, where 1n(relative risk) increased with cumulative exposure (log‐linear model) or with log‐transformed cumulative exposure (log–log model).
Results
The BaP and BSM cumulative exposure metrics were highly correlated (r = 0.94). The increase in model precision using BaP over BSM was 14% for bladder cancer and 5% for lung cancer; no difference was observed for AMI. The log‐linear BaP model provided the best fit for bladder cancer. The log–log dose–response models, where risk of disease plateaus at high exposure levels, were the best‐fitting models for lung cancer and AMI.
Conclusion
BaP and BSM were both strongly associated with bladder and lung cancer and modestly associated with AMI. Similar conclusions regarding the associations could be made regardless of the exposure metric.
doi:10.1136/oem.2006.028928
PMCID: PMC2078451  PMID: 17053015
9.  Sex- and Subtype-Specific Analysis of H2AFX Polymorphisms in Non-Hodgkin Lymphoma 
PLoS ONE  2013;8(9):e74619.
H2AFX encodes a histone variant involved in signaling sites of DNA damage and recruiting repair factors. Genetic variants in H2AFX may influence risk of non-Hodgkin lymphoma (NHL), a heterogeneous group of lymphoid tumors that are characterized by chromosomal translocations. We previously reported that rs2509049, a common variant in the promoter of H2AFX, was associated with risk for NHL in the British Columbia population. Here we report results for 13 single nucleotide polymorphisms (SNPs) in 100 Kb surrounding H2AFX in an expanded collection of 568 NHL cases and 547 controls. After correction for multiple testing, significant associations were present for mantle cell lymphoma (p=0.007 for rs604714) and all B-cell lymphomas (p=0.046 for rs2509049). Strong linkage disequilibrium in the 5 Kb upstream of H2AFX limited the ability to determine which specific SNP (rs2509049, rs7759, rs8551, rs643788, rs604714, or rs603826), if any, was responsible. There was a significant interaction between sex and rs2509049 in the all B-cell lymphomas group (p=0.002); a sex-stratified analysis revealed that the association was confined to females (p=0.001). Neither the overall nor the female-specific association with rs2509049 was replicated in any of four independent NHL sample sets. Meta-analysis of all five study populations (3,882 B-cell NHL cases and 3,718 controls) supported a weak association with B-cell lymphoma (OR=0.92, 95% CI=0.86-0.99, p=0.034), although this association was not significant after exclusion of the British Columbia data. Further research into the potential sex-specificity of the H2AFX-NHL association may identify a subset of NHL cases that are influenced by genotype at this locus.
doi:10.1371/journal.pone.0074619
PMCID: PMC3775730  PMID: 24069324
10.  Genetic Variation in Cell Death Genes and Risk of Non-Hodgkin Lymphoma 
PLoS ONE  2012;7(2):e31560.
Background
Non-Hodgkin lymphomas are a heterogeneous group of solid tumours that constitute the 5th highest cause of cancer mortality in the United States and Canada. Poor control of cell death in lymphocytes can lead to autoimmune disease or cancer, making genes involved in programmed cell death of lymphocytes logical candidate genes for lymphoma susceptibility.
Materials and Methods
We tested for genetic association with NHL and NHL subtypes, of SNPs in lymphocyte cell death genes using an established population-based study. 17 candidate genes were chosen based on biological function, with 123 SNPs tested. These included tagSNPs from HapMap and novel SNPs discovered by re-sequencing 47 cases in genes for which SNP representation was judged to be low. The main analysis, which estimated odds ratios by fitting data to an additive logistic regression model, used European ancestry samples that passed quality control measures (569 cases and 547 controls). A two-tiered approach for multiple testing correction was used: correction for number of tests within each gene by permutation-based methodology, followed by correction for the number of genes tested using the false discovery rate.
Results
Variant rs928883, near miR-155, showed an association (OR per A-allele: 2.80 [95% CI: 1.63–4.82]; pF = 0.027) with marginal zone lymphoma that is significant after correction for multiple testing.
Conclusions
This is the first reported association between a germline polymorphism at a miRNA locus and lymphoma.
doi:10.1371/journal.pone.0031560
PMCID: PMC3274532  PMID: 22347493
11.  Chronic and Acute Effects of Coal Tar Pitch Exposure and Cardiopulmonary Mortality Among Aluminum Smelter Workers 
American Journal of Epidemiology  2010;172(7):790-799.
Air pollution causes several adverse cardiovascular and respiratory effects. In occupational studies, where levels of particulate matter and polycyclic aromatic hydrocarbons (PAHs) are higher, the evidence is inconsistent. The effects of acute and chronic PAH exposure on cardiopulmonary mortality were examined within a Kitimat, Canada, aluminum smelter cohort (n = 7,026) linked to a national mortality database (1957–1999). No standardized mortality ratio was significantly elevated compared with the province's population. Smoking-adjusted internal comparisons were conducted using Cox regression for male subjects (n = 6,423). Ischemic heart disease (IHD) mortality (n = 281) was associated with cumulative benzo[a]pyrene (B(a)P) exposure (hazard ratio = 1.62, 95% confidence interval: 1.06, 2.46) in the highest category. A monotonic but nonsignificant trend was observed with chronic B(a)P exposure and acute myocardial infarction (n = 184). When follow-up was restricted to active employment, the hazard ratio for IHD was 2.39 (95% confidence interval: 0.95, 6.05) in the highest cumulative B(a)P category. The stronger associations observed during employment suggest that risk may not persist after exposure cessation. No associations with recent or current exposure were observed. IHD was associated with chronic (but not current) PAH exposure in a high-exposure occupational setting. Given the widespread workplace exposure to PAHs and heart disease's high prevalence, even modest associations produce a high burden.
doi:10.1093/aje/kwq208
PMCID: PMC2984260  PMID: 20702507
air pollutants; cohort studies; heart diseases; occupational diseases; polycyclic hydrocarbons, aromatic
12.  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.
doi:10.1093/aje/kwq167
PMCID: PMC2950815  PMID: 20720098
birth order; case-control studies; lymphoma, non-Hodgkin; selection bias; social class
13.  Cost–Effective Prediction of Gender-Labeling Errors and Estimation of Gender-Labeling Error Rates in Candidate-Gene Association Studies 
We describe a statistical approach to predict gender-labeling errors in candidate-gene association studies, when Y-chromosome markers have not been included in the genotyping set. The approach adds value to methods that consider only the heterozygosity of X-chromosome SNPs, by incorporating available information about the intensity of X-chromosome SNPs in candidate genes relative to autosomal SNPs from the same individual. To our knowledge, no published methods formalize a framework in which heterozygosity and relative intensity are simultaneously taken into account. Our method offers the advantage that, in the genotyping set, no additional space is required beyond that already assigned to X-chromosome SNPs in the candidate genes. We also show how the predictions can be used in a two-phase sampling design to estimate the gender-labeling error rates for an entire study, at a fraction of the cost of a conventional design.
doi:10.3389/fgene.2011.00031
PMCID: PMC3270323  PMID: 22303327
candidate-gene association study; gender-labeling errors; X-chromosome SNPs; genotype intensities; heterozygosity; two-phase sampling design; error rates; quality control
14.  Exposure to Multiple Pesticides and Risk of Non-Hodgkin Lymphoma in Men from Six Canadian Provinces 
Non-Hodgkin lymphoma (NHL) has been linked to several agricultural exposures, including some commonly used pesticides. Although there is a significant body of literature examining the effects of exposure to individual pesticides on NHL, the impact of exposure to multiple pesticides or specific pesticide combinations has not been explored in depth. Data from a six-province Canadian case-control study conducted between 1991 and 1994 were analyzed to investigate the relationship between NHL, the total number of pesticides used and some common pesticide combinations. Cases (n = 513) were identified through hospital records and provincial cancer registries and controls (n = 1,506), frequency matched to cases by age and province of residence, were obtained through provincial health records, telephone listings, or voter lists. In multiple logistic regression analyses, risk of NHL increased with the number of pesticides used. Similar results were obtained in analyses restricted to herbicides, insecticides and several pesticide classes. Odds ratios increased further when only ‘potentially carcinogenic’ pesticides were considered (OR[one pesticide] = 1.30, 95% CI = 0.90–1.88; OR[two to four] = 1.54, CI = 1.11–2.12; OR[five or more] = 1.94, CI = 1.17–3.23). Elevated risks were also found among those reporting use of malathion in combination with several other pesticides. These analyses support and extend previous findings that the risk of NHL increases with the number of pesticides used and some pesticide combinations.
doi:10.3390/ijerph8062320
PMCID: PMC3138027  PMID: 21776232
occupational cancer; non-Hodgkin lymphoma; pesticides; case-control study
15.  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.
doi:10.1093/aje/kwp383
PMCID: PMC2842204  PMID: 20047977
lymphoma; lymphoma, non-Hodgkin; lymphotoxin-alpha; meta-analysis; polymorphism, genetic; polymorphism, single nucleotide; tumor necrosis factor-alpha
17.  Cancer incidence and adverse pregnancy outcome in registered nurses potentially exposed to antineoplastic drugs 
BMC Nursing  2010;9:15.
Background
To determine the relationships of potential occupational exposure to antineoplastic drugs with cancer incidence and adverse pregnancy outcomes in a historical prospective cohort study of female registered nurses (RNs) from British Columbia, Canada (BC).
Methods
Female RNs registered with a professional regulatory body for at least one year between 1974 and 2000 formed the cohort (n = 56,213). The identifier file was linked to Canadian cancer registries. An RN offspring cohort from 1986 was created by linkages with the BC Birth and Health Status Registries. Exposure was assessed by work history in oncology or cancer agencies (method 1) and by estimating weighted duration of exposure developed from a survey of pharmacists and nursing unit administrators of all provincial hospitals and treatment centers and the work history of the nurses (method 2). Relative risks (RR) were calculated using Poisson regression for cancer incidence and odds ratios (OR) were calculated for congenital anomaly, stillbirth, low birth weight, and prematurity incidence, with 95% confidence intervals.
Results
In comparison with other female RNs, method 1 revealed that RNs who ever worked in a cancer center or in an oncology nursing unit had an increased risk of breast cancer (RR = 1.83; 95% CI = 1.03 - 3.23, 12 cases) and their offspring were at risk for congenital anomalies of the eye (OR = 3.46, 95% CI = 1.08 - 11.14, 3 cases). Method 2 revealed that RNs classified as having the highest weighted durations of exposure to antineoplastic drugs had an excess risk of cancer of the rectum (RR = 1.87, 95% CI = 1.07 - 3.29, 14 cases). No statistically significant increased risks of leukemia, other cancers, stillbirth, low birth weight, prematurity, or other congenital anomalies in the RNs' offspring were noted.
Conclusions
Female RNs having had potential exposure to antineoplastic drugs were not found to have an excess risk of leukemia, stillbirth, or congenital anomalies in their offspring, with the exception of congenital anomalies of the eye, based on only three cases; however, elevated risks of breast and rectal cancer were observed.
doi:10.1186/1472-6955-9-15
PMCID: PMC2949748  PMID: 20846432
18.  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.
doi:10.1158/0008-5472.CAN-08-4372
PMCID: PMC2758272  PMID: 19654312
non-Hodgkin lymphoma; atopy; case-control; pooled analysis; risk
19.  HCV co-infection in HIV positive population in British Columbia, Canada 
BMC Public Health  2010;10:225.
Background
As HIV and hepatitis C (HCV) share some modes of transmission co-infection is not uncommon. This study used a population-based sample of HIV and HCV tested individuals to determine the prevalence of HIV/HCV co-infection, the sequence of virus diagnoses, and demographic and associated risk factors.
Methods
Positive cases of HIV were linked to the combined laboratory database (of negative and positive HCV antibody results) and HCV reported cases in British Columbia (BC).
Results
Of 4,598 HIV cases with personal identifiers, 3,219 (70%) were linked to the combined HCV database, 1,700 (53%) of these were anti-HCV positive. HCV was diagnosed first in 52% of co-infected cases (median time to HIV identification 3 1/2 years). HIV and HCV was diagnosed within a two week window in 26% of cases. Among individuals who were diagnosed with HIV infection at baseline, subsequent diagnoses of HCV infection was independently associated with: i) intravenous drug use (IDU) in males and females, Hazard Ratio (HR) = 6.64 (95% CI: 4.86-9.07) and 9.76 (95% CI: 5.76-16.54) respectively; ii) reported Aboriginal ethnicity in females HR = 2.09 (95% CI: 1.34-3.27) and iii) males not identified as men-who-have-sex-with-men (MSM), HR = 2.99 (95% CI: 2.09-4.27).
Identification of HCV first compared to HIV first was independently associated with IDU in males and females OR = 2.83 (95% CI: 1.84-4.37) and 2.25 (95% CI: 1.15-4.39) respectively, but not Aboriginal ethnicity or MSM. HIV was identified first in 22%, with median time to HCV identification of 15 months;
Conclusion
The ability to link BC public health and laboratory HIV and HCV information provided a unique opportunity to explore demographic and risk factors associated with HIV/HCV co-infection. Over half of persons with HIV infection who were tested for HCV were anti-HCV positive; half of these had HCV diagnosed first with HIV identification a median 3.5 years later. This highlights the importance of public health follow-up and harm reduction measures for people identified with HCV to prevent subsequent HIV infection.
doi:10.1186/1471-2458-10-225
PMCID: PMC2868820  PMID: 20429917
20.  Genetic variants at 6p21.33 are associated with susceptibility to follicular lymphoma 
Nature genetics  2009;41(8):873-875.
We conducted genome-wide association studies of non-Hodgkin lymphoma using Illumina HumanHap550 BeadChips to identify subtype-specific associations in follicular, diffuse large B-cell and chronic lymphocytic leukemia/small lymphocytic lymphomas. We found that rs6457327 on 6p21.33 was associated with susceptibility to follicular lymphoma (FL, N=189 cases/592 controls) with validation in an additional 456 FL cases and 2,785 controls (combined allelic p-value=4.7×10−11). The region of strongest association overlaps C6orf15(STG), located near psoriasis susceptibility region 1(PSORS1).
doi:10.1038/ng.419
PMCID: PMC2823809  PMID: 19620980
21.  Ethnicity and incidence of Hodgkin lymphoma in Canadian population 
BMC Cancer  2009;9:141.
Background
Research has shown that ethnicity is a significant predictor of Hodgkin lymphoma (HL). Variations in cancer incidence among ethnic groups in the same country can lead to important information in the search for etiological factors. Other risk factors important in the etiology of HL are medical history and exposure to pesticides. In this report we investigated the association between ethnicity and HL in the presence of medical history, and exposure to pesticides.
Methods
The data resulting from a matched population-based case-control study conducted in six provinces of Canada (Ontario, Quebec, Manitoba, Saskatchewan, Alberta, and British Columbia) was analyzed to determine whether or not there was any association between ethnicity and incidence of HL when adjusted for personal medical history and pesticide exposure. Information on ethnicity, personal medical history, and pesticide exposure was collected by questionnaires via mail on 316 men diagnosed with HL; and on 1506 controls. A conditional logistic regression was utilized and results were presented as odds ratios and 95% confidence intervals.
Results
In our study population, the distribution of ethnic groups was: 38.5% North American, 15% British, 8.4% Western European, 8.2% Eastern European, 1.7% Asian, 1.4% Scandinavian and 27% of other ethnic origin. Compared to North Americans (i) the risk of HL was greater among the Eastern European descendents (Odds Ratio (ORadj): 1.82; 95% confidence interval (CI): 1.02, 3.25) and Western European (ORadj: 1.62; 95% CI: 0.95–2.76) descent population (borderline significance at 5% level); and (ii) the risk of HL was lower in Asian descents. Diagnosis with measles (ORadj: 0.72, 95% C.I.: 0.53–0.98) and/or positive history of allergy desensitization shots (ORadj: 0.55, 95% C.I.: 0.30–0.99) were negatively associated with the incidence of HL, while diagnosis with acne (ORadj: 2.12, 95% C.I.: 1.19–3.78), shingles (ORadj: 2.41, 95% C.I.: 1.38–4.22) and positive family history of cancer (ORadj: 1.93, 95% C.I.: 1.40–2.65) increased the risk of HL. Exposure to individual herbicide dichlorprop showed an increased risk of HL (ORadj: 6.35, 95% C.I.: 1.56–25.92).
Conclusion
In Canada, compared to North Americans descendents, the risk of HL was significantly greater among the Eastern European and Western European descent population. Our results related to association between ethnicity and HL support the findings reported by other researchers. Our data showed that subjects who were diagnosed with measles or had allergy desensitization shots negatively associated with the incidence of HL; and other medical conditions, ever diagnosed with acne, and positive family history of cancer were positively associated with the incidence of HL.
doi:10.1186/1471-2407-9-141
PMCID: PMC2690601  PMID: 19432977
22.  Clustering of cancer among families of cases with Hodgkin Lymphoma (HL), Multiple Myeloma (MM), Non-Hodgkin's Lymphoma (NHL), Soft Tissue Sarcoma (STS) and control subjects 
BMC Cancer  2009;9:70.
Background
A positive family history of chronic diseases including cancer can be used as an index of genetic and shared environmental influences. The tumours studied have several putative risk factors in common including occupational exposure to certain pesticides and a positive family history of cancer.
Methods
We conducted population-based studies of Hodgkin lymphoma (HL), Multiple Myeloma (MM), non-Hodgkin's Lymphoma (NHL), and Soft Tissue Sarcoma (STS) among male incident case and control subjects in six Canadian provinces. The postal questionnaire was used to collect personal demographic data, a medical history, a lifetime occupational history, smoking pattern, and the information on family history of cancer. The family history of cancer was restricted to first degree relatives and included relationship to the index subjects and the types of tumours diagnosed among relatives. The information was collected on 1528 cases (HL (n = 316), MM (n = 342), NHL (n = 513), STS (n = 357)) and 1506 age ± 2 years and province of residence matched control subjects. Conditional logistic regression analyses adjusted for the matching variables were conducted.
Results
We found that most families were cancer free, and a minority included two or more affected relatives. HL [(ORadj (95% CI) 1.79 (1.33, 2.42)], MM (1.38(1.07, 1.78)), NHL (1.43 (1.15, 1.77)), and STS cases (1.30(1.00, 1.68)) had higher incidence of cancer if any first degree relative was affected with cancer compared to control families. Constructing mutually exclusive categories combining "family history of cancer" (yes, no) and "pesticide exposure ≥10 hours per year" (yes, no) indicated that a positive family history was important for HL (2.25(1.61, 3.15)), and for the combination of the two exposures increased risk for MM (1.69(1.14,2.51)). Also, a positive family history of cancer both with (1.72 (1.21, 2.45)) and without pesticide exposure (1.43(1.12, 1.83)) increased risk of NHL.
Conclusion
HL, MM, NHL, and STS cases had higher incidence of cancer if any first degree relative affected with cancer compared to control families. A positive family history of cancer and/or shared environmental exposure to agricultural chemicals play an important role in the development of cancer.
doi:10.1186/1471-2407-9-70
PMCID: PMC2653543  PMID: 19250521
23.  Occupational exposures and non-Hodgkin's lymphoma: Canadian case-control study 
Environmental Health  2008;7:44.
Background
The objective was to study the association between Non-Hodgkin's Lymphoma (NHL) and occupational exposures related to long held occupations among males in six provinces of Canada.
Methods
A population based case-control study was conducted from 1991 to 1994. Males with newly diagnosed NHL (ICD-10) were stratified by province of residence and age group. A total of 513 incident cases and 1506 population based controls were included in the analysis. Conditional logistic regression was conducted to fit statistical models.
Results
Based on conditional logistic regression modeling, the following factors independently increased the risk of NHL: farmer and machinist as long held occupations; constant exposure to diesel exhaust fumes; constant exposure to ionizing radiation (radium); and personal history of another cancer. Men who had worked for 20 years or more as farmer and machinist were the most likely to develop NHL.
Conclusion
An increased risk of developing NHL is associated with the following: long held occupations of faer and machinist; exposure to diesel fumes; and exposure to ionizing radiation (radium). The risk of NHL increased with the duration of employment as a farmer or machinist.
doi:10.1186/1476-069X-7-44
PMCID: PMC2531101  PMID: 18687133
24.  Identifying related cancer types based on their incidence among people with multiple cancers 
Background
There are several reasons that someone might be diagnosed with more than one primary cancer. The aim of this analysis was to determine combinations of cancer types that occur more often than expected. The expected values in previous analyses are based on age-and-gender-adjusted risks in the population. However, if cancer in people with multiple primaries is somehow different than cancer in people with a single primary, then the expected numbers should not be based on all diagnoses in the population.
Methods
In people with two or more cancer types, the probability that a specific type is diagnosed was determined as the number of diagnoses for that cancer type divided by the total number of cancer diagnoses. If two types of cancer occur independently of one another, then the probability that someone will develop both cancers by chance is the product of the individual probabilities for each type. The expected number of people with both cancers is the number of people at risk multiplied by the separate probabilities for each cancer. We performed the analysis on records of cancer diagnoses in British Columbia, Canada between 1970 and 2004.
Results
There were 28,159 people with records of multiple primary cancers between 1970 and 2004, including 1,492 people with between three and seven diagnoses. Among both men and women, the combinations of esophageal cancer with melanoma, and kidney cancer with oral cancer, are observed more than twice as often as expected.
Conclusion
Our analysis suggests there are several pairs of primary cancers that might be related by a shared etiological factor. We think that our method is more appropriate than others when multiple diagnoses of primary cancer are unlikely to be the result of therapeutic or diagnostic procedures.
doi:10.1186/1742-7622-3-17
PMCID: PMC1636044  PMID: 17090329
25.  A randomized controlled trial of an extensive lifestyle management intervention (ELMI) following cardiac rehabilitation: study design and baseline data 
Background
Cardiac rehabilitation programs (CRP) represent comprehensive interventions that are typically limited to four months. Following completion of CRP, it appears that risk factors and lifestyle behaviours may deteriorate. The Extensive Lifestyle Management Intervention (ELMI) Following Cardiac Rehabilitation trial will investigate the benefits of a randomized intervention to prevent these adverse changes.
Methods
Patients with ischemic heart disease (IHD) were randomized following a standard CRP to the ELMI or to usual care. The ELMI program is a case-managed intervention aimed at individualizing risk factor and lifestyle management based on current treatment guidelines. The program consists of cardiac rehabilitation sessions, telephone follow-up and risk factor and lifestyle counselling sessions. Health professionals work with participants using behavioural counselling and communications with participants' family physicians. Usual care participants return to their family physicians' care, and come to the study clinic only to undergo annual outcomes assessment. The primary outcome is change in IHD global risk after four years. Secondary outcomes include combined cardiovascular events, health care utilization, lifestyle adherence, quality of life and risk factors.
Results
Over 28 months, 302 men and women were randomized. This represented 29% of the total population screened. The average age of study participants is 64 years, 18% are women, 53% have had a previous myocardial infarction, 73% have undergone previous revascularization and 20% have diabetes mellitus. Ischemic heart disease risk factors for the entire cohort improved significantly after subjects had gone through previous CRPs. Baseline risk factors, lifestyle behaviours and medications were similar between the groups.
Conclusions
This study population is representative of patients completing a standard CRP. Results of the ELMI trial will provide valuable information for the future design of CRPs.
doi:10.1186/1468-6708-3-9
PMCID: PMC149404  PMID: 12473163
Cardiac rehabilitation; risk factor management; lifestyle management; compliance; ischemic heart disease; randomized trials

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