Risk of Non-Hodgkin's Lymphoma and Family History of Lymphatic, Hematologic, and Other Cancers

Assessing and attenuating the impact of selection bias on spatial cluster detection studies

Spatial cluster analyses are commonly used in epidemiologic studies of case-control data to detect whether certain areas in a study region have an excess of disease risk. Case-control studies are susceptible to potential biases including selection bias, which can result from non-participation of eligible subjects in the study. However, there has been no systematic evaluation of the effects of non-participation on the findings of spatial cluster analyses. In this paper, we perform a simulation study assessing the effect of non-participation on spatial cluster analysis using the local spatial scan statistic under a variety of scenarios that vary the location and rates of study non-participation and the presence and intensity of a zone of elevated risk for disease for simulated case-control studies. We find that geographic areas of lower participation among controls than cases can greatly inflate false-positive rates for identification of artificial spatial clusters. Additionally, we find that even modest non-participation outside of a true zone of elevated risk can decrease spatial power to identify the true zone. We propose a spatial algorithm to correct for potentially spatially structured non-participation that compares the spatial distributions of the observed sample and underlying population. We demonstrate its ability to markedly decrease false positive rates in the absence of elevated risk and resist decreasing spatial sensitivity to detect true zones of elevated risk. We apply our method to a case-control study of non-Hodgkin lymphoma. Our findings suggest that greater attention should be paid to the potential effects of non-participation in spatial cluster studies.

Modeling variation in mixture effects over space with a Bayesian spatially varying mixture model

Mixture analysis is an emerging statistical tool in epidemiological research that seeks to estimate the health effects associated with mixtures of several exposures. This approach acknowledges that individuals experience many simultaneous exposures and it can estimate the relative importance of components in the mixture. Health effects due to mixtures may vary over space driven by to political, demographic, environmental, or other differences. In such cases, estimating a global mixture effect without accounting for spatial variation would induce bias in effect estimates and potentially lower statistical power. To date, no methods have been developed to estimate spatially varying chemical mixture effects. We developed a Bayesian spatially varying mixture model that estimates spatially varying mixture effects and the importance weights of components in the mixture, while adjusting for covariates. We demonstrate the efficacy of the model through a simulation study that varies the number of mixtures (one and two) and spatial pattern (global, one-dimensional, radial) and magnitude of mixture effects, showing that the model is able to accurately reproduce the spatial pattern of mixture effects across a diverse set of scenarios. Finally, we apply our model to a multi-center case-control study of non-Hodgkin lymphoma (NHL) in Detroit, Iowa, Los Angeles, and Seattle. We identify significant spatially varying positive and inverse associations with NHL for two mixtures of pesticides in Iowa and do not find strong spatial effects at the other three centers. In conclusion, the Bayesian spatially varying mixture model represents a novel method for modeling spatial variation in mixture effects.

Modeling historic neighborhood deprivation and non-Hodgkin lymphoma risk

Many studies have identified associations between neighborhood deprivation and disease, emphasizing the importance of social determinants of health. However, when studying diseases with long latency periods such as cancers, considering the timing of exposures for deprivation becomes more important. In this study, we estimated the associations between neighborhood deprivation indices at several time points and risk of non-Hodgkin lymphoma (NHL) in a population-based case-control study at four study centers - Detroit, Iowa, Los Angeles County, and Seattle (1998-2000). We used the Bayesian index regression model and residential histories to estimate neighborhood deprivation index effects in crude models and adjusted for four chemical mixtures measured in house dust and individual-level covariates. We found that neighborhood deprivation in 1980, approximately twenty years before study entry, provided better model fit than did neighborhood deprivation at 1990 and 2000. We identified several statistically significant associations between neighborhood deprivation in 1980 and NHL risk in Iowa and among long-term (20+ years) residents of Detroit. The most important variables in these indices were median gross rent as a percentage of household income in Iowa and percent of single-parent households with at least one child and median household income in Detroit. Associations remained statistically significant after adjustment for individual-level covariates and chemical mixtures, providing evidence for historic neighborhood deprivation as a risk factor for NHL and motivating future research to uncover the specific carcinogens driving these associations in deprived areas.

Modeling historic environmental pollutant exposures and non-Hodgkin lymphoma risk

Environmental exposures to chemicals are suspected risk factors for non-Hodgkin lymphoma (NHL), but few studies have assessed historic environmental risk factors. In this study, we estimated the associations between NHL and 1) historic environmental pollutant emissions from the Risk Screening Environmental Indicators (RSEI) model, which uses a database from the Environmental Protection Agency of toxic release emissions to air, water, and land, and 2) chemical mixtures measured in house dust (groups of PCBs, PAHs, and two mixtures of pesticides) for study participants enrolled in the NCI-SEER population-based case-control study (1998-2000) at four SEER centers - Detroit, Iowa, Los Angeles County, and Seattle. We assigned 11 years of annual temporally-varying historic environmental exposure scores by intersecting residential locations from participants' residential histories with a fine grid from the RSEI model and by performing inverse distance weighting between facilities releasing specific carcinogenic chemicals and residential locations for spatially-precise exposure assignments. We used Bayesian index low-rank kriging multiple membership models to identify important lag times for RSEI scores, cumulative effects of RSEI scores, and specific carcinogenic chemical releases into the environment. We found a significant positive association between RSEI scores and NHL at the maximum time lag of 11 years (OR = 1.17, 95% CI (1.06, 1.32)) and a significant cumulative RSEI score effect (OR = 1.30, 95% CI (1.02, 1.84)) for long-term residents in Detroit, where benzene and trichloroethylene were the most important chemicals driving this association. Additionally, we identified significant inverse associations for two study centers and time lags that did not persist in cumulative exposure models. Large weights for dichloromethane and pentachlorophenol in models of cumulative exposure also support evidence for their association with NHL risk. These results underscore the importance of considering historic and cumulative environmental exposures and using residential histories for diseases with long latency periods such as NHL.

Physical activity and the risk of non-Hodgkin lymphoma subtypes: A pooled analysis

Non-Hodgkin lymphoma (NHL) is composed of a heterogeneous collection of subtypes with considerable differences in genetics, biology and aetiology. Studies to date on physical activity and NHL risk have not had sufficient sample size to evaluate whether associations differ by subtype. We pooled data from nine case-control studies to examine the association between moderate-to-vigorous intensity physical activity (MVPA) and risk of NHL overall and by subtype (diffuse large B-cell lymphoma, follicular lymphoma, chronic lymphocytic leukaemia/small lymphocytic lymphoma, marginal zone lymphoma and mature T-cell lymphoma). A total of 5653 cases and 9115 controls were included in the pooled analysis. Physical activity was harmonised across nine studies and modelled as study-specific tertiles. Multinomial logistic regression was used to estimate the association between physical activity and NHL, adjusting for confounders. The overall odds of NHL was 13% lower among participants in the most active tertile of MVPA compared to the least active tertile (adjusted odds ratio = 0.87, 95% CI = 0.80, 0.95). Similar decreases were observed across NHL subtypes. In summary, in this pooled analysis of case-control studies, physical activity was associated with a modest risk reduction for each NHL subtype examined and with overall NHL.

Estimating mixture effects and cumulative spatial risk over time simultaneously using a Bayesian index low-rank kriging multiple membership model

The exposome is an ideal in public health research that posits that individuals experience risk for adverse health outcomes from a wide variety of sources over their lifecourse. There have been increases in data collection in the various components of the exposome, but novel statistical methods are needed that capture multiple dimensions of risk at once. We introduce a Bayesian index low-rank kriging (LRK) multiple membership model (MMM) to simultaneously estimate the health effects of one or more groups of exposures, the relative importance of exposure components, and cumulative spatial risk over time using residential histories. The model employs an MMM to consider all residential locations for subjects weighted by duration and LRK to increase computational efficiency. We demonstrate the performance of the Bayesian index LRK-MMM through a simulation study, showing that the model accurately and consistently estimates the health effects of one or several group indices and has high power to identify a region of elevated spatial risk due to unmeasured environmental exposures. Finally, we apply our model to data from a multicenter case-control study of non-Hodgkin lymphoma (NHL), finding a significant positive association between one index of pesticides and risk for NHL in Iowa. Additionally, we find an area of significantly elevated spatial risk for NHL in Los Angeles. In conclusion, our Bayesian index LRK-MMM represents a step forward toward bringing the ideals of the exposome into practice for environmental risk analyzes.

B-Cell NHL Subtype Risk Associated with Autoimmune Conditions and PRS

BACKGROUND

A previous International Lymphoma Epidemiology (InterLymph) Consortium evaluation of joint associations between five immune gene variants and autoimmune conditions reported interactions between B-cell response-mediated autoimmune conditions and the rs1800629 genotype on risk of B-cell non-Hodgkin lymphoma (NHL) subtypes. Here, we extend that evaluation using NHL subtype-specific polygenic risk scores (PRS) constructed from loci identified in genome-wide association studies of three common B-cell NHL subtypes.

METHODS

In a pooled analysis of NHL cases and controls of Caucasian descent from 14 participating InterLymph studies, we evaluated joint associations between B-cell-mediated autoimmune conditions and tertile (T) of PRS for risk of diffuse large B-cell lymphoma (DLBCL; n = 1,914), follicular lymphoma (n = 1,733), and marginal zone lymphoma (MZL; n = 407), using unconditional logistic regression.

RESULTS

We demonstrated a positive association of DLBCL PRS with DLBCL risk [T2 vs. T1: OR = 1.24; 95% confidence interval (CI), 1.08-1.43; T3 vs. T1: OR = 1.81; 95% CI, 1.59-2.07; P-trend (Ptrend) < 0.0001]. DLBCL risk also increased with increasing PRS tertile among those with an autoimmune condition, being highest for those with a B-cell-mediated autoimmune condition and a T3 PRS [OR = 6.46 vs. no autoimmune condition and a T1 PRS, Ptrend < 0.0001, P-interaction (Pinteraction) = 0.49]. Follicular lymphoma and MZL risk demonstrated no evidence of joint associations or significant Pinteraction.

CONCLUSIONS

Our results suggest that PRS constructed from currently known subtype-specific loci may not necessarily capture biological pathways shared with autoimmune conditions.

IMPACT

Targeted genetic (PRS) screening among population subsets with autoimmune conditions may offer opportunities for identifying those at highest risk for (and early detection from) DLBCL.

No Association Observed Between Coffee Intake and Risk of Non-Hodgkin's Lymphoma among Postmenopausal Women

BACKGROUND

Some preliminary studies indicate that components in coffee may have anticarcinogenic effects. However, the association between coffee-drinking habits and the risk of NHL remain controversial.

OBJECTIVE

To examine the relationship between coffee intake and non-Hodgkin's lymphoma (NHL) incidence in a large prospective study of postmenopausal US women.

DESIGN AND PARTICIPANTS/SETTING

The participants included 74,935 women from the Women's Health Initiative Observational Study (WHI-OS) who were recruited from 1993 through 1998. Information about coffee-drinking habits was collected at baseline via self-administered questionnaires.

MAIN OUTCOME MEASURES

Newly diagnosed NHL was validated by medical records and pathology records. Separate analyses were performed for the following three subtypes of NHL: diffuse large B-cell lymphoma (DLBCL (n=244)), follicular lymphoma (FL (n=166)), and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL (n=64)).

STATISTICAL ANALYSES PERFORMED

Age-adjusted and multivariable-adjusted Cox proportional hazards models were used to determine associations of coffee intake (specifically, the total amount of coffee consumed daily, coffee types, and coffee preparation methods) with risk of NHL.

RESULTS

A total of 851 women developed NHL during a median 18.34 years of follow-up (range, 0.01 to 24.30 years; SD ± 6.63 years). Overall, no associations were observed between coffee intake and risk of NHL regardless of the total amount of daily coffee intake (P-value for trend test = 0.90), caffeinated (P-value=0.55) or decaffeinated coffee intake (P-value=0.78), and filtered or unfiltered coffee intake (P-value=0.91) after controlling for sociodemographic factors, lifestyle risk factors, and clinical risk factors/current medical conditions. No significant associations were observed between coffee intake with specific subtypes of NHL. A statistically significant interaction was found between alcohol intake, coffee intake, and incident NHL (P-value for interaction=0.02) based on the adjusted analysis. Specifically, among women who frequently consumed alcohol (>7 drinks/week), those who had moderate coffee intake (2-3 cups coffee/day) had a significantly reduced risk of developing NHL (HR:0.61, 95%CI: 0.36-0.98), compared to those who did not drink coffee.

CONCLUSION

The findings from this study do not support an association between coffee consumption and NHL risk, irrespective of the total amount of daily coffee intake, coffee types, or coffee preparation methods.

Case-control investigation of occupational exposure to chlorinated solvents and non-Hodgkin's lymphoma

OBJECTIVES

Although many studies have investigated the association between trichloroethylene (TCE) exposure and non-Hodgkin's lymphoma (NHL), less is known about other chlorinated solvents. We extended our previous analysis of occupational TCE exposure in a multicentre population-based case-control study of NHL to investigate associations with five additional chlorinated solvents: 1,1,1,-trichloroethane, carbon tetrachloride, chloroform, methylene chloride and perchloroethylene.

METHODS

Cases (n=1189) and controls (n=982) provided detailed information on their occupational histories and workplace exposure to chlorinated solvents for selected occupations using job-specific interview modules. An industrial hygienist used this information and a review of the literature to assess occupational exposure to chlorinated solvents. We computed ORs and 95% CIs for different exposure metrics, with the unexposed group as the referent. We also computed ORs by NHL subtype.

RESULTS

High cumulative hours exposed to carbon tetrachloride was associated with NHL (>520 hours: OR 1.9; 95% CI 1.0 to 3.6; Ptrend=0.04). This association remained after restricting to jobs with high-intensity exposure (OR 2.0; 95% CI 1.1 to 3.8; P=0.03) and ≥90% exposure probability (OR 2.1; 95% CI 1.0 to 4.3; P=0.03), adjusting for TCE (OR 2.1; 95% CI 1.0- to 4.1; P=0.04) and incorporating a 15-year lag (OR 1.9; 95% CI 1.0 to 3.6; P=0.06). The other evaluated chlorinated solvents were not associated with NHL.

CONCLUSIONS

This is the first study using high-quality quantitative exposure assessment methods to identify a statistically significant elevated association between occupational exposure to carbon tetrachloride and NHL. Our findings, although limited by a small number of exposed cases, offer evidence that carbon tetrachloride may be a lymphomagen.

Young Adult and Usual Adult Body Mass Index and Multiple Myeloma Risk: A Pooled Analysis in the International Multiple Myeloma Consortium (IMMC)

Background: Multiple myeloma risk increases with higher adult body mass index (BMI). Emerging evidence also supports an association of young adult BMI with multiple myeloma. We undertook a pooled analysis of eight case-control studies to further evaluate anthropometric multiple myeloma risk factors, including young adult BMI.Methods: We conducted multivariable logistic regression analysis of usual adult anthropometric measures of 2,318 multiple myeloma cases and 9,609 controls, and of young adult BMI (age 25 or 30 years) for 1,164 cases and 3,629 controls.Results: In the pooled sample, multiple myeloma risk was positively associated with usual adult BMI; risk increased 9% per 5-kg/m2 increase in BMI [OR, 1.09; 95% confidence interval (CI), 1.04-1.14; P = 0.007]. We observed significant heterogeneity by study design (P = 0.04), noting the BMI-multiple myeloma association only for population-based studies (Ptrend = 0.0003). Young adult BMI was also positively associated with multiple myeloma (per 5-kg/m2; OR, 1.2; 95% CI, 1.1-1.3; P = 0.0002). Furthermore, we observed strong evidence of interaction between younger and usual adult BMI (Pinteraction <0.0001); we noted statistically significant associations with multiple myeloma for persons overweight (25-<30 kg/m2) or obese (30+ kg/m2) in both younger and usual adulthood (vs. individuals consistently <25 kg/m2), but not for those overweight or obese at only one time period.Conclusions: BMI-associated increases in multiple myeloma risk were highest for individuals who were overweight or obese throughout adulthood.Impact: These findings provide the strongest evidence to date that earlier and later adult BMI may increase multiple myeloma risk and suggest that healthy BMI maintenance throughout life may confer an added benefit of multiple myeloma prevention. Cancer Epidemiol Biomarkers Prev; 26(6); 876-85. ©2017 AACR.

Nonrandom occurrence of lymphoid cancer types in 140 families

We studied 140 families with two or more lymphoid cancers, including non-Hodgkin lymphoma (NHL), Hodgkin lymphoma (HL), chronic lymphocytic leukemia (CLL), and multiple myeloma (MM), for deviation from the population age of onset and lymphoid cancer co-occurrence patterns. Median familial NHL, HL, CLL and MM ages of onset are substantially earlier than comparable population data. NHL, HL and CLL (but not MM) also show earlier age of onset in later generations, known as anticipation. The co-occurrence of lymphoid cancers is significantly different from that expected based on population frequencies (p < .0001), and the pattern differs more in families with more affected members (p < .0001), suggesting specific lymphoid cancer combinations have a shared genetic basis. These families provide evidence for inherited factors that increase the risk of multiple lymphoid cancers. This study was approved by the BC Cancer Agency - University of British Columbia Clinical Research Ethics Board.

The burden of non-Hodgkin lymphoma in Central and South America

RATIONALE AND OBJECTIVE

The burden of non-Hodgkin lymphoma (NHL) has increased in some Central and South American countries. We describe the current patterns and trends in NHL incidence and mortality in Central and South America.

METHODS

We obtained regional- and national-level incidence data from 48 population-based cancer registries in 13 countries, and national-level cancer mortality data from the WHO mortality database for 18 countries. We estimated world population age-standardized incidence rates (ASRs) and mortality rates (ASMRs) per 100,000 person-years for 2003-2007, and presented distributions by histological subtype.

RESULTS

NHL incidence and mortality rates varied between countries by 2-8- and 6-fold, respectively. ASRs per 100,000 ranged from 1.4 to 10.9 among males and 1.3-9.2 among females. Corresponding ASMRs were between 0.5 and 4.8 among males and between 0.5 and 3.0 among females. The highest incidence was observed in Uruguay (males), Ecuador, Peru and Colombia (males). The highest mortality was seen in Uruguay and Costa Rica. Trends in NHL incidence and mortality in Argentina, Brazil, Chile and Costa Rica did not show marked changes. B-cell neoplasms and NHL not otherwise specified (NOS) accounted for 44% and 34% of all NHL cases. Diffuse large B-cell lymphoma, NOS, was the most frequent histological subtype.

CONCLUSION

The geographic variations in NHL rates may partially reflect differences in registration practices, disease classification, diagnostic practice, and death certification quality. There is a need for high-quality data and improvements in the accuracy of NHL histological diagnosis. Given the expected increase in NHL, careful monitoring of rates remains a priority to guide cancer control programs.

Primary cutaneous large B-cell non-Hodgkin lymphoma in first-degree relatives

Primary cutaneous non-Hodgkin's lymphoma is a heterogeneous group of lymphoproliferative disorders characterized by indolent course, virtually exclusive skin involvement and the absence of systemic disease. We present two brothers, whose mother died of gastric diffuse large B-cell lymphoma, in whom in a period of 4 years primary cutaneous large B-cell non-Hodgkin lymphoma of the skin of the head was diagnosed. They were treated with immunochemotherapy according to R-CHOP protocol (rituximab and adriblastine, cyclophosphamide, oncovine and prednisone) achieving a complete remission. The possible etiological mechanism of this familial lymphoma occurrence is discussed.

A case-control study of occupational exposure to trichloroethylene and non-Hodgkin lymphoma

BACKGROUND

Previous epidemiologic findings suggest an association between exposure to trichloroethylene (TCE), a chlorinated solvent primarily used for vapor degreasing of metal parts, and non-Hodgkin lymphoma (NHL).

OBJECTIVES

We investigated the association between occupational TCE exposure and NHL within a population-based case-control study using detailed exposure assessment methods.

METHODS

Cases (n = 1,189; 76% participation rate) and controls (n = 982; 52% participation rate) provided information on their occupational histories and, for selected occupations, on possible workplace exposure to TCE using job-specific interview modules. An industrial hygienist assessed potential TCE exposure based on this information and a review of the TCE industrial hygiene literature. We computed odds ratios (ORs) and 95% confidence intervals (CIs) relating NHL and different metrics of estimated TCE exposure, categorized using tertiles among exposed controls, with unexposed subjects as the reference group.

RESULTS

We observed associations with NHL for the highest tertiles of estimated average weekly exposure (23 exposed cases; OR = 2.5; 95% CI, 1.1–6.1) and cumulative exposure (24 exposed cases; OR = 2.3; 95% CI, 1.0-5.0) to TCE. Tests for trend with these metrics surpassed or approached statistical significance (p-value for trend = 0.02 and 0.08, respectively); however, we did not observe dose–response relationships across the exposure levels. Overall, neither duration nor intensity of exposure was associated with NHL, although we observed an association with the lowest tertile of exposure duration (OR = 2.1; 95% CI, 1.0-4.7).

CONCLUSIONS

Our findings offer additional support for an association between high levels of exposure to TCE and increased risk of NHL. However, we cannot rule out the possibility of confounding from other chlorinated solvents used for vapor degreasing and note that our exposure assessment methods have not been validated.

Dietary flavonoid intake and non-Hodgkin lymphoma risk

BACKGROUND

The role of dietary factors in non-Hodgkin lymphoma (NHL) risk is not yet well understood. Dietary flavonoids are polyphenolic compounds proposed to be anticarcinogenic. Flavonoids are well-characterized antioxidants and metal chelators, and certain flavonoids exhibit antiproliferative and antiestrogenic effects.

OBJECTIVE

We aimed to evaluate the hypothesis that higher flavonoid intake is associated with lower NHL risk.

DESIGN

During 1998-2000, we identified incident NHL cases aged 20-74 y from 4 US Surveillance, Epidemiology, and End Results cancer registries. Controls without history of NHL were selected by random-digit dialing or from Medicare files and frequency-matched to cases by age, center, race, and sex. Using 3 recently developed US Department of Agriculture nutrient-specific databases, flavonoid intake was estimated from participant responses to a 117-item food-frequency questionnaire (n = 466 cases and 390 controls). NHL risk in relation to flavonoid intake in quartiles was evaluated after adjustment for age, sex, registry, education, NHL family history, and energy intake.

RESULTS

Higher total flavonoid intake was significantly associated with lower risk of NHL (P for trend < 0.01): a 47% lower risk in the highest quartile of intake than in the lowest (95% CI: 31%, 73%). Higher intakes of flavonols, epicatechins, anthocyanidins, and proanthocyanidins were each significantly associated with decreased NHL risk. Similar patterns of risk were observed for the major NHL subtypes--diffuse large B-cell lymphoma (n = 167) and follicular lymphoma (n = 146).

CONCLUSION

A higher intake of flavonoids, dietary components with several putative anticarcinogenic activities, may be associated with lower NHL risk.

Common genetic variants in proinflammatory and other immunoregulatory genes and risk for non-Hodgkin lymphoma

Profound disruption of immune function is an established risk factor for non-Hodgkin lymphoma. We report here a large-scale evaluation of common genetic variants in immune genes and their role in lymphoma. We genotyped 57 single nucleotide polymorphisms (SNP) from 36 candidate immune genes in 1,172 non-Hodgkin lymphoma cases and 982 population-based controls from a US multicenter study. We calculated odds ratios (OR) and 95% confidence intervals (95% CI) for the association between individual SNP and haplotypes with non-Hodgkin lymphoma overall and five well-defined subtypes. A haplotype comprising SNPs in two proinflammatory cytokines, tumor necrosis factor-alpha and lymphotoxin-alpha (rs1800629, rs361525, rs1799724, rs909253, and rs2239704), increased non-Hodgkin lymphoma risk overall (OR, 1.31; 95% CI, 1.06-1.63; P = 0.01) and notably for diffuse large B cell (OR, 1.64; 95% CI, 1.23-2.19; P = 0.0007). A functional nonsynonymous SNP in the innate immune gene Fc gamma receptor 2A (FCGR2A; rs1801274) was also associated with non-Hodgkin lymphoma; AG and AA genotypes were associated with a 1.26-fold (95% CI, 1.01-1.56) and 1.41-fold (95% CI, 1.10-1.81) increased risk, respectively (P(trend) = 0.006). Among non-Hodgkin lymphoma subtypes, the association with FCGR2A was pronounced for follicular and small lymphocytic lymphomas. In conclusion, common variants in genes influencing proinflammatory and innate immune responses were associated with non-Hodgkin lymphoma risk overall and their effects could vary by subtype. Our results require replication but potentially provide important clues for investigating common genetic variants as susceptibility factors and in disease outcomes, treatment responses, and immunotherapy targets.

Immune mechanisms in non-Hodgkin lymphoma: joint effects of the TNF G308A and IL10 T3575A polymorphisms with non-Hodgkin lymphoma risk factors

Two common single nucleotide polymorphisms in immunoregulatory genes (TNF G308A, rs1800629 and IL10 T3575A, rs1800890) have been recently reported as risk factors for non-Hodgkin lymphoma (NHL) in a large pooled analysis. We systematically investigated the effects of other established NHL risk factors in relation to the tumor necrosis factor (TNF) G308A or interleukin 10 (IL10) T3575A genotypes. We calculated odds ratios (OR) and 95% confidence intervals (95% CI) from 1,172 cases and 982 population-based controls in a U.S. multicenter study. We investigated NHL overall and two common subtypes [diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma]. NHL risks were increased among those with both an autoimmune condition and the TNF G308A GA/AA (OR(NHL), 2.1; 95% CI, 1.0-4.2) or the IL10 T3575A TA/AA genotype (OR(NHL), 1.6; 95% CI, 0.9-2.6) compared with individuals without an autoimmune condition and with the common TNF G308A GG or IL10 T3575A TT genotype, respectively; results were similar for DLBCL and follicular lymphoma. We found that elevated DLBCL risk associated with last-born status was more pronounced among those with TNF G308A GA/AA (OR(DLBCL), 2.7; 95% CI, 1.1-6.4) or IL10 T3575A TA/AA (OR(DLBCL), 2.9; 95% CI, 1.6-5.2). Similarly, elevated DLBCL risk associated with obesity (body mass index, > or = 35 versus <25 kg/m(2)) was observed only among those with TNF G308A GA/AA (OR(DLBCL), 2.5; 95% CI, 1.1-5.7) or IL10 T3575A TA/AA genotypes (OR(DLBCL), 2.0; 95% CI, 1.1-3.5). These exploratory results require replication but provide evidence that autoimmune conditions, late birth order, and obesity act partly through a common inflammatory pathway, posing a greater risk to individuals with variant TNF and IL10 genotypes than those with wild-type alleles.

Exposure to Solvents and Risk of Non-Hodgkin Lymphoma: Clues on Putative Mechanisms

Malignant lymphomas are a group of diseases of uncertain etiology. Both environmental factors and genetic susceptibility have been reported as risk factors. We have conducted a population-based case-control study in Italy: all newly diagnosed cases of malignant lymphoma, in males and females ages 20 to 74 years in the 1991 to 1993 period, were identified; the control group was comprised of a random sample of the general population resident in each of the areas under study, stratified by sex and 5-year age groups. Overall, 1,428 non-Hodgkin lymphoma (NHL) cases and 1,530 controls were interviewed. Experts from each geographic area examined questionnaire data and assigned a level of probability and intensity of exposure to a range of chemical groups and individual chemicals. For those in the medium/high level of exposure, there was an increased risk of NHL for exposure to benzene, xylene, and toluene. We have examined the hypothesis that the effect of solvents is related to their immunotoxicity by analyzing the interaction with a previous history of autoimmune disease. We have found an apparent, though not statistically significant, increased risk of NHL in those with both exposure to benzene and a history of autoimmune disease (odds ratio, 16.3; 95% confidence interval, 0.8-321). In addition, an odds ratio of 29.8 (95% confidence interval, 1.4-650.2, based on nine exposed cases) was associated with high-level exposure to benzene in those with a positive family history of malignant hematologic neoplasms. Both hypotheses (i.e., the interaction with autoimmune diseases and with familial predisposition) indirectly suggest that an immunologic mechanism could be involved in lymphomagenesis from solvents.

Metabolic gene variants and risk of non-Hodgkin's lymphoma

Genes involved in metabolism of environmental chemical exposures exhibit sequence variability that may mediate the risk of non-Hodgkin's lymphoma. We evaluated associations between non-Hodgkin's lymphoma and 15 variants in AHR, CYP1A1, CYP1A2, CYP1B1, CYP2C9, CYP2E1, GSTP1, GSTM3, EPHX1, NQO1, and PON1. Cases were identified from four Surveillance, Epidemiology, and End Results registries in the United States, and population-based controls were identified through random-digit dialing and Medicare eligibility files. Metabolic gene variants were characterized for the 1,172 (89% of total) cases and 982 (93%) controls who provided biological samples for genotyping. Subjects who were heterozygous or homozygous for the cytochrome P450 gene variant CYP1B1 V432L G allele were at slightly greater risk of non-Hodgkin's lymphoma [odds ratio (OR), 1.27; 95% confidence interval (95% CI), 0.97-1.65]; these results were consistent across B-cell lymphoma subtypes and among both non-Hispanic White and Black subjects, although not statistically significant. The CYP2E1 -1054T allele was associated with decreased risk of non-Hodgkin's lymphoma (CT and TT genotypes combined OR, 0.59; 95% CI, 0.37-0.93), and this pattern was observed among all histologic subtypes. The numbers of cases of particular subtypes were rather small for stable estimates, but we noted that the PON1 L55M AA allele, associated with slightly increased risk of non-Hodgkin's lymphoma (variant homozygotes OR, 1.36; 95% CI, 0.96-1.95), was most strongly associated with follicular non-Hodgkin's lymphoma and T-cell lymphoma, with ORs for variant homozygotes of 2.12 and 2.93, respectively. There was no overall association with non-Hodgkin's lymphoma for the other gene variants we examined. The modest effects we observed may reflect the context of exposures within the general population represented in our study.

Family history of hemolymphopoietic and other cancers and risk of non-Hodgkin's lymphoma

We investigated the risk of lymphomas, hemolymphopoietic (HLP) cancers (including lymphomas), and non-HLP cancers in first-degree relatives of non-Hodgkin's lymphoma (NHL) cases in an Italian case-control study on 225 patients (median age, 59 years) with a new diagnosis of NHL and 504 hospital controls (median age, 63 years), admitted for a wide spectrum of acute, nonneoplastic, nonimmune conditions. We estimated odds ratios (OR) adjusted for sex, age, family size, and other potential confounders. We also built the cohort of all first-degree relatives and computed age and sex adjusted hazard ratios (HR) using proportional hazard models. A history of lymphoma in first-degree relatives was reported by 5 NHL cases and 3 controls [OR, 3.2; 95% confidence interval (95% CI), 0.7-14.4] whereas 14 cases and 11 controls reported a family history of HLP cancers (OR, 3.0; 95% CI, 1.2-7.0). The HR of relatives of NHL cases, compared with relatives of controls, was 4.5 (95% CI, 1.1-18.8) for lymphomas, 3.5 (95% CI, 1.5-7.4) for HLP cancers, 1.6 (95% CI, 1.3-2.0) for all cancers, and 1.0 (95% CI, 0.9-1.1) for all causes of deaths. The HRs were higher for relatives of NHL cases diagnosed before the age of 50 years: 7.1 for HLP cancers, 2.0 for all cancers, and 1.6 for all deaths. A family history of cancer of the liver (OR, 2.1; 95% CI, 1.0-4.2), breast (OR, 2.0; 95% CI, 1.0-3.6), and kidney (OR, 4.6; 95% CI, 1.0-20.9) increased NHL risk. The OR was also elevated for all cancer sites (OR, 1.7 95% CI, 1.2-2.4) and the risk increased with the number of affected relatives also when HLP cancers were excluded.

Vegetables, fruit, and antioxidant-related nutrients and risk of non-Hodgkin lymphoma: a National Cancer Institute-Surveillance, Epidemiology, and End Results population-based case-control study

BACKGROUND

Factors related to DNA damage and altered immunologic responses, such as reactive oxygen species production, are associated with the risk of non-Hodgkin lymphoma (NHL).

OBJECTIVE

The aim was to evaluate NHL risk with intakes of vegetables, fruit, and nutrients involved in antioxidant activities.

DESIGN

Incident case subjects aged 20-74 y were identified between 1998 and 2000 from a National Cancer Institute-sponsored study by using four Surveillance, Epidemiology, and End Results registries. Control subjects, who were selected by random dialing (< 65 y) and from Medicare files (> or = 65 y), were matched to cases by age, center, race, and sex. Of 1321 case and 1057 control subjects who enrolled, dietary data were collected on a subset (466 cases and 391 controls). Carotenoid intakes were estimated by using updated values from the US Department of Agriculture nutrient databases. Unconditional logistic regression models were used to estimate odds ratios (ORs) and 95% CIs.

RESULTS

NHL risk was inversely associated with higher number of weekly servings of all vegetables (multivariable OR for highest compared with lowest quartile: 0.58; 95% CI: 0.35, 0.95; P for trend = 0.04), green leafy vegetables (OR: 0.59; 95% CI: 0.36, 0.96; P for trend = 0.01), and cruciferous vegetables (OR: 0.62; 95% CI: 0.39, 1.00; P for trend = 0.05) and with higher daily intakes of lutein and zeaxanthin (OR: 0.54; 95% CI: 0.32, 0.91; P for trend = 0.06) and zinc (OR: 0.58; 95% CI: 0.36, 0.91; P for trend = 0.02). An effect modification by exercise and NHL subtype was observed with some food groups and nutrients.

CONCLUSION

Higher intakes of vegetables, lutein and zeaxanthin, and zinc are associated with a lower NHL risk.

Proximity to crops and residential exposure to agricultural herbicides in iowa

Rural residents can be exposed to agricultural pesticides through the proximity of their homes to crop fields. Previously, we developed a method to create historical crop maps using a geographic information system. The aim of the present study was to determine whether crop maps are useful for predicting levels of crop herbicides in carpet dust samples from residences. From homes of participants in a case-control study of non-Hodgkin lymphoma in Iowa (1998-2000), we collected vacuum cleaner dust and measured 14 herbicides with high use on corn and soybeans in Iowa. Of 112 homes, 58% of residences had crops within 500 m of their home, an intermediate distance for primary drift from aerial and ground applications. Detection rates for herbicides ranged from 0% for metribuzin and cyanazine to 95% for 2,4-dichlorophenoxyacetic acid. Six herbicides used almost exclusively in agriculture were detected in 28% of homes. Detections and concentrations were highest in homes with an active farmer. Increasing acreage of corn and soybean fields within 750 m of homes was associated with significantly elevated odds of detecting agricultural herbicides compared with homes with no crops within 750 m (adjusted odds ratio per 10 acres = 1.06; 95% confidence interval, 1.02-1.11). Herbicide concentrations also increased significantly with increasing acreage within 750 m. We evaluated the distance of crop fields from the home at < 100, 101-250, 251-500, and 501-750 m. Including the crop buffer distance parameters in the model did not significantly improve the fit compared with a model with total acres within 750 m. Our results indicate that crop maps may be a useful method for estimating levels of herbicides in homes from nearby crop fields.

Persistent Organochlorine Chemicals in Plasma and Risk of Non-Hodgkin's Lymphoma

Polychlorinated biphenyls (PCB) have been suspected as possible contributors to increasing non-Hodgkin's lymphoma incidence during the latter half of the 20th century based on their toxicologic properties and provocative epidemiologic reports. We investigated PCBs and other organochlorines and risk of non-Hodgkin's lymphoma in a population-based case-control study in the United States. Congeners of PCBs (including coplanar congeners), dioxins, furans and pesticides or pesticide metabolites were measured in plasma of 100 untreated cases and 100 control subjects. We used a multiple imputation procedure to fill in missing values of levels determined to be below the detection limits. Risks of non-Hodgkin's lymphoma associated with each analyte were estimated using conditional logistic regression for the continuous measure, exposure quartiles, trend across quartile categories, and exposures above the 95th percentile. Certain PCB congeners were associated with increased risk of non-Hodgkin's lymphoma, including coplanar PCBs 156, 180, and 194, with odds ratios for the highest versus lowest quartile ranging from 2.7 to 3.5, and significant trends. Each of the furan congeners was associated with risk of non-Hodgkin's lymphoma, as were total furans, with 3.5-fold increased risk for the highest versus lowest quartile and a significant trend across quartiles (P = 0.006). The toxic equivalency quotient (TEQ), a summed metric that weights congeners by their dioxin-like potency, was associated with non-Hodgkin's lymphoma, with 35% increased risk per 10 TEQ pg/g lipid (95% confidence interval, 1.02-1.79). Our results add to existing literature, which suggests that exposure to organochlorines contributes to non-Hodgkin's lymphoma risk; these risks were most apparent for certain PCBs and furans.

Cigarette Smoking and Risk of Non-Hodgkin Lymphoma: A Pooled Analysis from the International Lymphoma Epidemiology Consortium (InterLymph)

BACKGROUND

The International Lymphoma Epidemiology Consortium (InterLymph) provides an opportunity to analyze the relationship between cigarette smoking and non-Hodgkin lymphoma with sufficient statistical power to consider non-Hodgkin lymphoma subtype. The results from previous studies of this relationship have been inconsistent, likely due to the small sample sizes that arose from stratification by disease subtype. To clarify the role of cigarette smoking in the etiology of non-Hodgkin lymphoma, we conducted a pooled analysis of original patient data from nine case-control studies of non-Hodgkin lymphoma conducted in the United States, Europe, and Australia.

METHODS

Original data were obtained from each study and uniformly coded. Risk estimates from fixed-effects and two-stage random-effects models were compared to determine the impact of interstudy heterogeneity. Odds ratios (OR) and 95% confidence intervals (95% CI) were derived from unconditional logistic regression models, controlling for study center, age, sex, and race.

RESULTS

In our pooled study population of 6,594 cases and 8,892 controls, smoking was associated with slightly increased risk estimates (OR, 1.07; 95% CI, 1.00-1.15). Stratification by non-Hodgkin lymphoma subtype revealed that the most consistent association between cigarette smoking and non-Hodgkin lymphoma was observed among follicular lymphomas (n = 1452). Compared with nonsmokers, current smokers had a higher OR for follicular lymphoma (1.31; 95% CI, 1.12-1.52) than former smokers (1.06; 95% CI, 0.93-1.22). Current heavy smoking (> or = 36 pack-years) was associated with a 45% increased OR for follicular lymphoma (1.45; 95% CI, 1.15-1.82) compared with nonsmokers.

CONCLUSIONS

Cigarette smoking may increase the risk of developing follicular lymphoma but does not seem to affect risk of the other non-Hodgkin lymphoma subtypes we examined. Future research is needed to determine the biological mechanism responsible for our subtype-specific results.