A pooled analysis of three studies evaluating genetic variation in innate immunity genes and non-Hodgkin lymphoma risk

Genetic variation in immune-related genes may play a role in the development of non-Hodgkin lymphoma (NHL). To test the hypothesis that innate immunity polymorphisms may be associated with NHL risk, we genotyped 144 tag single nucleotide polymorphisms (tagSNPs) capturing common genetic variation within 12 innate immunity gene regions in three independent population-based case-control studies (1946 cases and 1808 controls). Gene-based analyses found IL1RN to be associated with NHL risk (minP = 0·03); specifically, IL1RN rs2637988 was associated with an increased risk of NHL (per-allele odds ratio = 1·15, 95% confidence interval = 1·05-1·27; P(trend) = 0·003), which was consistent across study, subtype, and gender. FCGR2A was also associated with a decreased risk of the follicular lymphoma NHL subtype (minP = 0·03). Our findings suggest that genetic variation in IL1RN and FCGR2A may play a role in lymphomagenesis. Given that conflicting results have been reported regarding the association between IL1RN SNPs and NHL risk, a larger number of innate immunity genes with sufficient genomic coverage should be evaluated systematically across many studies.

Melanoma incidence rates among whites in the U.S. Military

BACKGROUND

The U.S. Military and general populations may differ in the exposure to sunlight and other risk factors for melanoma and therefore the incidence rates of melanoma may be different in these two populations. However, few studies have compared melanoma incidence rates and trends over time between the military and the general population.

METHODS

Melanoma incidence rates from 1990 to 2004 among white active-duty military personnel and the general U.S. population were compared using data from the Department of Defense Automated Central Tumor Registry and the National Cancer Institute Surveillance, Epidemiology, and End Results program.

RESULTS

Age-adjusted melanoma rates overall were significantly lower in the military than in the general population; the incidence rate ratio was 0.75 for men and 0.56 for women. Age-specific rates, however, were significantly lower among individuals younger than 45 years, but significantly higher among those 45 years or older (P < 0.05). Melanoma incidence increased from 1990-1994 to 2000-2004 in both populations, with the most rapid increase (40%) among younger men in the military. Melanoma incidence rates also varied by branch of military service; rates were highest in the air force.

CONCLUSION

These results suggest that melanoma incidence rate patterns differ between the military and the general population.

IMPACT

Further studies of risk factors for melanoma in the military are needed to explain these findings.

Abstract B80: Melanoma incidence rates among whites in the U.S. military

Melanoma incidence rates may differ between the U.S. active-duty military population and the U.S. general population due to potentially higher exposure to sunlight among military personnel and other risk factors for melanoma. However, few studies have compared melanoma incidence rates and trends over time between the military and the general population. The purpose of this study was to examine melanoma incidence rates from 1990 to 2004 among white active-duty military personnel and the general U.S. population, using data from the military's Automated Central Tumor Registry (ACTUR) and the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program. Age-adjusted melanoma rates overall were significantly lower in the military than in the general population; the incidence rate ratio (IRR) was 0.75 for men and 0.56 for women. Age-specific rates, however, were significantly lower among younger individuals aged &lt;45 years but significantly higher among those aged 45 years or older (p-values&lt;0.05). Melanoma incidence rose from 1990-1994 to 2000-2004 in both populations, with the most rapid increase (40%) among younger men in the military. Melanoma incidence rates also varied by branch of military service with rates highest in the Air Force. These results suggest that melanoma incidence rate patterns differ between the two populations, and further studies of risk factors for melanoma in the military are needed to explain these findings.

Citation Information: Cancer Prev Res 2010;3(12 Suppl):B80.

Polymorphisms in DNA repair genes and risk of non-Hodgkin lymphoma in a pooled analysis of three studies

Genetic variations in DNA repair genes are thought to play an important role in the pathogenesis and development of non-Hodgkin lymphoma (NHL). To further explore this hypothesis, we genotyped 319 tag single nucleotide polymorphisms (SNPs) in 27 DNA repair gene regions in 1946 cases and 1808 controls pooled from three population-based case-control studies of NHL in the US and Australia. Relative risks of NHL and NHL subtypes in relation to SNP genotypes were assessed using logistic regression. Associations of gene regions and pathways with NHL or NHL subtypes were explored using the minP and tail-strength statistics, respectively. Overall, genetic polymorphisms within the DNA repair pathway were associated with NHL (P = 0·005). Similar associations were seen with the double-strand break repair (P = 0·02) and nucleotide excision repair (P = 0·04) pathways. Five SNPs (BLM rs441399, RAD50 rs2237060, FAM82A2 rs2304583, ERCC3 rs4150506, and XRCC4 rs13178127) were particularly noteworthy because their gene regions were significantly associated with NHL or NHL subtypes (minP ≤ 0·05), or because of high level of statistical significance (P ≤ 0·005) and consistent findings across the three studies. These results support the hypothesis that common genetic polymorphisms in human DNA repair genes may modify the risk of NHL.

Genome-wide association study of follicular lymphoma identifies a risk locus at 6p21.32

To identify susceptibility loci for non-Hodgkin lymphoma subtypes, we conducted a three-stage genome-wide association study. We identified two variants associated with follicular lymphoma at 6p21.32 (rs10484561, combined P = 1.12 x 10(-29) and rs7755224, combined P = 2.00 x 10(-19); r(2) = 1.0), supporting the idea that major histocompatibility complex genetic variation influences follicular lymphoma susceptibility. We also found confirmatory evidence of a previously reported association between chronic lymphocytic leukemia/small lymphocytic lymphoma and rs735665 (combined P = 4.24 x 10(-9)).

Genetic variation in caspase genes and risk of non-Hodgkin lymphoma: a pooled analysis of 3 population-based case-control studies

Caspases play a critical role in regulation of apoptosis, cell differentiation, inflammation, and innate immunity, and several are mutated or have altered expression in non-Hodgkin lymphoma (NHL). To study the impact of genetic variation in caspases on NHL risk, we analyzed tag single nucleotide polymorphisms (SNPs) in 12 caspase and related genes in 3 population-based case-control studies (1946 cases and 1808 controls). Gene-based analysis, adjusting for the number of tagSNPs genotyped in each gene, showed significant associations for CASP8, CASP9, and CASP1. SNP-based analysis showed that CASP8 rs6736233 (odds ratio (OR) (CG) = 1.21; OR(CC) = 2.13; P trend = .011); CASP9 rs4661636 (OR(CT) = 0.89; OR(TT) = 0.77; P trend = .011); and CASP1 rs1785882 (OR(AT) = 1.12; OR(AA) = 1.30; P trend = .0054) were significantly associated with NHL risk and consistent across studies. It is noteworthy that genetic variants in CASP8 were associated with risk of all major NHL subtypes. Our findings suggest that genetic variation in caspases may play an important role in lymphomagenesis.

Genetic polymorphisms in nitric oxide synthase genes modify the relationship between vegetable and fruit intake and risk of non-Hodgkin lymphoma

Oxidative damage caused by reactive oxygen species and other free radicals is involved in carcinogenesis. It has been suggested that high vegetable and fruit intake may reduce the risk of non-Hodgkin lymphoma (NHL) as vegetables and fruit are rich in antioxidants. The aim of this study is to evaluate the interaction of vegetable and fruit intake with genetic polymorphisms in oxidative stress pathway genes and NHL risk. This hypothesis was investigated in a population-based case-control study of NHL and NHL histologic subtypes in women from Connecticut, including 513 histologically confirmed incident cases and 591 randomly selected controls. Gene-vegetable/fruit joint effects were estimated using unconditional logistic regression model. The false discovery rate method was applied to adjust for multiple comparisons. Significant interactions with vegetable and fruit intake were mainly found for genetic polymorphisms on nitric oxide synthase (NOS) genes among those with diffuse large B-cell lymphoma and follicular lymphoma. Two single nucleotide polymorphisms in the NOS1 gene were found to significantly modify the association between total vegetable and fruit intake and risk of NHL overall, as well as the risk of follicular lymphoma. When vegetables, bean vegetables, cruciferous vegetables, green leafy vegetables, red vegetables, yellow/orange vegetables, fruit, and citrus fruits were examined separately, strong interaction effects were narrowed to vegetable intake among patients with diffuse large B-cell lymphoma. Our results suggest that genetic polymorphisms in oxidative stress pathway genes, especially in the NOS genes, modify the association between vegetable and fruit intake and risk of NHL.

Genetic variation in cell cycle and apoptosis related genes and multiple myeloma risk

Genetic variation may be an important risk factor for multiple myeloma. A hallmark of tumor formation and growth is cell cycle dysregulation and apoptosis avoidance. We previously reported the association of genetic variation in caspase genes, the apoptotic-regulating family, and multiple myeloma risk. To further examine if genetic variation in key cell cycle and apoptosis genes alters multiple myeloma risk, we genotyped 276 tag SNPs in 27 gene regions in a population-based case-control study of non-Hispanic Caucasian women (108 cases; 482 controls) in Connecticut. Logistic regression assessed the effect of each SNP on multiple myeloma risk and the minP test assessed the association at the gene region level. Three gene regions were significantly associated with risk of multiple myeloma (BAX minP=0.018, CASP9 minP=0.025, and RIPK1 minP=0.037). Further explorations identified the most significant variant of BAX, RIPK1, and CASP9 to be rs1042265, rs9391981, and rs751643, respectively. The A variant at rs1042265 (OR(GA+AA)=0.40, 95% CI=0.21-0.78) and the C variant at rs9391981 (OR(GC+CC)=0.32, 95% CI=0.12-0.81) were associated with a decreased risk of multiple myeloma. The G variant at rs7516435 was associated with an increased risk of multiple myeloma (OR(AG)=1.48, 95% CI=0.94-2.32; OR(GG)=2.59, 95% CI=1.30-5.15; p(trend)=0.005). Haplotype analyses supported the SNP findings. These findings suggest that genetic variation in cell cycle and apoptosis genes may play a key role in multiple myeloma and warrant further investigation through replication studies.

Inferring past pesticide exposures: a matrix of individual active ingredients in home and garden pesticides used in past decades

BACKGROUND

In retrospective studies of the health effects of home and garden pesticides, self-reported information typically forms the basis for exposure assessment. Study participants generally find it easier to remember the types of pests treated than the specific pesticides used. However, if the goal of the study is to assess disease risk from specific chemicals, the investigator must be able to link the pest type treated with specific chemicals or products.

OBJECTIVES

Our goal was to develop a "pesticide-exposure matrix" that would list active ingredients on the market for treating different types of pests in past years, and provide an estimate of the probability that each active ingredient was used.

METHODS

We used several different methods for deriving the active ingredient lists and estimating the probabilities. These methods are described in this article, along with a sample calculation and data sources for each.

RESULTS

The pesticide-exposure matrix lists active ingredients and their probabilities of use for 96 distinct scenarios defined by year (1976, 1980, 1990, 2000), applicator type (consumer, professional), and pest type (12 categories). Calculations and data sources for all 96 scenarios are provided online.

CONCLUSIONS

Although we are confident that the active ingredient lists are reasonably accurate for most scenarios, we acknowledge possible sources of error in the probability estimates. Despite these limitations, the pesticide-exposure matrix should provide valuable information to researchers interested in the chronic health effects of residential pesticide exposure.

Genetic polymorphisms in the oxidative stress pathway and susceptibility to non-Hodgkin lymphoma

Oxidative damage caused by reactive oxygen species (ROS) and other free radicals is involved in a number of pathological conditions including cancer. In a population-based case-control study of non-Hodgkin lymphoma (NHL) (n = 518 cases, 597 controls) among women in Connecticut, we analyzed one or more single nucleotide polymorphisms (SNPs) in ten candidate genes (AKR1A1, AKR1C1, AKR1C3, CYBA, GPX1, MPO, NOS2A, NOS3, OGG1, and SOD2) that mediate oxidative stress directly or indirectly in the NADPH oxidase-dependent respiratory burst. Odds ratios (OR) and 95% confidence intervals (CI) were adjusted for age and race. Polymorphisms in AKR1A1 and CYBA were significantly associated with increased risk of NHL. There was a 1.7-fold (95% CI = 1.2-2.4, P = 0.0047) increased risk of NHL for individuals who were variant homozygous for the AKR1A1 (IVS5 + 282T > C) SNP. The effect was most pronounced for risk of diffuse large B-cell lymphoma, but risk estimates were non-significantly elevated for other common B-cell histologies and T-cell lymphomas as well. In addition, individuals variant homozygous for the CYBA (Ex4 + 11C > T) SNP had a 1.6-fold (95% CI = 1.1-2.4, P = 0.019) increased risk of NHL that was particularly pronounced for T-cell lymphoma (OR = 3.5, 95% CI = 1.3-9.6, P = 0.013), but was also associated with non-significant increased risks for each of the common B-cell histologies. These results suggest that SNPs in genes related to the oxidative stress pathway may be associated with increased risk of NHL.

Genetic variants in caspase genes and susceptibility to non-Hodgkin lymphoma

The caspase proteins are essential for the regulation of normal B cell development and regulation of apoptosis. We investigated five single nucleotide polymorphisms in four key caspase genes, CASP3 [Ex8-280C>A (rs6948) and Ex8+567T>C (rs1049216)], CASP8 Ex14-271A>T (rs13113), CASP9 Ex5+32G>A (rs1052576) and CASP10 Ex3-171A>G (rs3900115) to determine whether they alter risk for non-Hodgkin lymphoma (NHL) in a population-based case-control study of women in Connecticut (461 cases and 535 controls). Variants in CASP3 and CASP9 were significantly associated with a decreased risk for NHL, particularly follicular lymphoma [e.g. CASP3 Ex8+567T>C odds ratio (OR)(CC+TC) = 0.4, 95% confidence interval (CI) = 0.3-0.7; and CASP9 Ex5+32G>A OR(AA+AG) = 0.6, 95% CI = 0.4-1.0]. Further, variants in CASP3, CASP8 and CASP10 were associated with a decreased risk of marginal zone lymphoma and variants in CASP3 and CASP10 were associated with a lower risk of chronic lymphocytic leukemia and related subtypes. The striking protective associations observed for polymorphisms in all four genes for NHL and/or one or more subtypes suggest that genetic variation in CASP genes may play an important role in the etiology of NHL.

Polymorphisms in DNA repair genes and risk of non-Hodgkin lymphoma among women in Connecticut

Several hereditary syndromes characterized by defective DNA repair are associated with high risk of non-Hodgkin lymphoma (NHL). To explore whether common polymorphisms in DNA repair genes affect risk of NHL in the general population, we evaluated the association between single nucleotide polymorphisms (SNPs) in DNA repair genes and risk of NHL in a population-based case-control study among women in Connecticut. A total of 518 NHL cases and 597 controls recruited into the study provided a biologic sample. Thirty-two SNPs in 18 genes involved in several DNA repair pathways were genotyped. Genotype data were analyzed by unconditional logistic regression adjusting for age and race. SNPs in four genes (ERCC5, ERCC2, WRN, and BRCA1) were associated with altered risk of NHL and diffuse large B-cell lymphoma (DLBCL), the major B cell subtype. In particular, ERCC5 Asp1104His was associated with increased risk of NHL overall (OR: 1.46; 95% CI: 1.13-1.88; P=0.004), DLBCL (OR: 1.44; 95% CI: 0.99-2.09; P=0.058), and also T cell lymphoma. WRN Cys1367Arg was associated with decreased risk of NHL overall (OR: 0.71; 95% CI: 0.56-0.91; P=0.007) and DLBCL (OR: 0.66; 95% CI: 0.45-0.95; P=0.024), as well as follicular and marginal zone lymphomas. Genetic polymorphisms in DNA repair genes, particularly ERCC5 and WRN, may play a role in the pathogenesis of NHL, especially for DLBCL. Further work is needed to extend these findings by carrying out extended haplotype analyses of these and related genes and to replicate the observations in other studies.

Cytokine polymorphisms in the Th1/Th2 pathway and susceptibility to non-Hodgkin lymphoma

Studies have demonstrated that common polymorphisms in Th1 and Th2 cytokine genes can alter gene expression, modulate the balance between Th1/Th2 responsiveness, and influence susceptibility for autoimmune disorders, infectious diseases, and cancer. We analyzed one or more single nucleotide polymorphisms (SNPs) in 20 candidate Th1/Th2 genes in a population-based case-control study of non-Hodgkin lymphoma (NHL; n = 518 cases, 597 controls) among women in Connecticut. SNPs in critical genes, IL4, IL5, IL6, and IL10, were associated with risk for NHL and in some instances with a specific histologic subtype. Analysis of 4 SNPs in the IL10 promoter (-3575T>A, -1082A>G, -819C>T, and -592C>A) revealed that both the AGCC haplotype (odds ratio [OR] = 1.54, 95% confidence interval [CI] = 1.21-1.96, P < .001) and the TATA haplotype (OR = 1.37, 95% CI = 1.05-1.79, P = .02) were associated with increased risk for B-cell lymphomas. In contrast, the IL4-1098G allele was associated with increased risk of T-cell lymphomas (OR = 3.84; 95% CI = 1.79-8.22; P < .001). Further, the IL10 and IL4 SNP associations remained significant after adjusting for multiple comparisons. These results suggest that SNPs in Th2 cytokine genes may be associated with risk of NHL.

Breast cancer risk factors according to joint estrogen receptor and progesterone receptor status

BACKGROUND

We investigated risk factor patterns for subtypes of breast cancer characterized by joint estrogen receptor (ER) and progesterone receptor (PR) status in a hospital-based case-control study.

METHODS

ER and PR tumor status were determined immunohisotchemically. Risk factors of interest were entered into a multiple polychotomous logistic regression model simultaneously; odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Using this model, cases in the four tumor subtypes (ER+PR+, ER-PR-, ER+PR-, ER-PR+) were compared simultaneously to controls. A Wald test for heterogeneity across the four subtypes was conducted, as well as a case-case comparison between the two most biologically disparate subtypes, ER+PR+ and ER-PR-.

RESULTS

The receptor status distribution was as follows: 33% ER+PR+, 34% ER-PR-, 20% ER+PR-, and 13% ER-PR+. Among 317 cases and 401 controls, we found significant heterogeneity across the four tumor subtypes for older age at first full-term pregnancy (p=0.04) and post-menopausal status (p=0.04). For older age at first full-term pregnancy, an elevated risk was found for the ER+PR- subtype (OR=2.5; 95% CI: 1.2-5.1). For post-menopausal status, elevated risks were found for both the ER+PR+ (OR=2.4; 95% CI: 1.1-4.9) and ER+PR- (OR=7.2; 95% CI: 2.4-21.7) subtypes. From the case-case comparisons, we found that cases, who had consumed alcohol for more than 1 year were 3.4 times more likely to have ER+PR+ tumors than ER-PR- tumors (95% CI: 1.4-8.4).

CONCLUSIONS

Certain breast cancer risk factors may vary by ER and PR status, and joint ER/PR status should be taken into account in future studies of risk factor estimates.

Polychlorinated biphenyls and breast cancer risk by combined estrogen and progesterone receptor status

Studies have suggested that breast cancer risk factor profiles may vary according to joint estrogen receptor (ER) and progesterone receptor (PR) tumor status. Most of the published literature to date which has investigated the association between exposure to organochlorine compounds and breast cancer has reported null or weak associations. If, indeed, the classification by hormonal receptor status identifies different forms of breast cancer, then assessing the risk of exposure to polychlorinated biphenyls (PCBs) on breast cancer as one disease or stratifying based on ER or PR status alone may obscure the association between PCBs and breast cancer. A hospital-based case-control study of 266 cases and 347 benign breast disease controls was conducted to examine the association of blood serum and adipose tissue concentrations of PCBs with breast cancer by joint ER/PR status. Total PCBs were measured in blood serum, and the following PCB congeners were measured in breast adipose tissue: 74, 118, 138, 153, 156, 170, 180, 183, 187. We did not detect any clear relationship or change in breast cancer risk based on joint ER/PR tumor status for body burden of PCBs, whether measured in blood serum or breast adipose tissue, by total PCBs or for specific congeners. These results confirm previous findings in the literature of no positive association between environmental exposure to PCBs and risk of breast cancer.

Non-Hodgkin's lymphoma among asthmatics exposed to pesticides

We conducted a pooled analysis of population-based case-control studies in Iowa, Minnesota and Nebraska to investigate whether asthma modifies risk of non-Hodgkin's lymphoma (NHL) associated with pesticide exposures. Cases (n = 872) diagnosed with NHL from 1980 to 1986 and frequency-matched controls (n = 2,381) randomly selected from the same geographic areas as the cases were included. Information on use of pesticides and history of asthma was based on interviews. Unconditional logistic regression was used to calculate ORs, adjusted for age, state and vital status. Of all subjects, 177 (45 cases, 132 controls) reported having been told by their doctor that they had asthma. Subjects with an asthma history had a nonsignificantly lower risk of NHL than nonasthmatics (OR = 0.6, 95% CI 0.3-1.4), and there was no main effect of pesticide exposure (OR = 1.0, 95% CI 0.8-1.2). However, asthmatics tended to have larger ORs associated with exposure to pesticides than nonasthmatics. The OR among asthmatics was 1.8 (95% CI 1.1-3.2) for ever-use of crop insecticides, 2.7 (95% CI 1.0-7.2) for chlordane, 2.4 (95% CI 1.0-5.7) for lindane and 3.7 (95% CI 1.3-10.9) for fonofos. Among nonasthmatics, ORs were 1.1 (0.9-1.3), 1.5 (1.1-2.2), 1.3 (0.97-1.8) and 1.6 (1.0-2.4), respectively. Although there is limited power for assessing interaction, our results suggest that the risk of NHL among asthmatics with pesticide exposure may be higher than among nonasthmatics with pesticide exposure.

Cigarette smoking and risk of non-Hodgkin lymphoma subtypes among women

Previous studies of the relationship between cigarette smoking and non-Hodgkin lymphoma (NHL) have yielded conflicting results, perhaps because most studies have evaluated the risk for all NHL subtypes combined. Data from a population-based case–control study conducted among women in Connecticut were used to evaluate the impact of cigarette smoking on the risk of NHL by histologic type, tumour grade, and immunologic type. A total of 601 histologically confirmed, incident cases of NHL and 718 population-based controls provided in-person interviews. A standardised, structured questionnaire was used to collect information on each subject's current smoking status, age at initiation, duration and intensity of smoking, and cumulative lifetime exposure to smoking. Our data suggest that cigarette smoking does not alter the risk of all NHL subtypes combined. However, increased risk of follicular lymphoma appears to be associated with increased intensity and duration of smoking, and cumulative lifetime exposure to smoking. Compared with nonsmokers, women with a cumulative lifetime exposure of 16–33 pack-years and 34 pack-years or greater experience 50% increased risk (OR=1.5, 95% CI 0.9–2.5) and 80% increased risk (OR=1.8, 95% CI 1.1–3.2), respectively, of follicular lymphoma (P for linear trend=0.05). Our study findings are consistent with several previous epidemiologic studies suggesting that cigarette smoking increases the risk of follicular lymphoma. This research highlights the importance of distinguishing between NHL subtypes in future research on the aetiology of NHL.

Integrative assessment of multiple pesticides as risk factors for non-Hodgkin's lymphoma among men

BACKGROUND

An increased rate of non-Hodgkin's lymphoma (NHL) has been repeatedly observed among farmers, but identification of specific exposures that explain this observation has proven difficult.

METHODS

During the 1980s, the National Cancer Institute conducted three case-control studies of NHL in the midwestern United States. These pooled data were used to examine pesticide exposures in farming as risk factors for NHL in men. The large sample size (n = 3417) allowed analysis of 47 pesticides simultaneously, controlling for potential confounding by other pesticides in the model, and adjusting the estimates based on a prespecified variance to make them more stable.

RESULTS

Reported use of several individual pesticides was associated with increased NHL incidence, including organophosphate insecticides coumaphos, diazinon, and fonofos, insecticides chlordane, dieldrin, and copper acetoarsenite, and herbicides atrazine, glyphosate, and sodium chlorate. A subanalysis of these "potentially carcinogenic" pesticides suggested a positive trend of risk with exposure to increasing numbers.

CONCLUSION

Consideration of multiple exposures is important in accurately estimating specific effects and in evaluating realistic exposure scenarios.

Glutathione S-transferase M1 and T1 genetic polymorphisms, alcohol consumption and breast cancer risk

Alcohol consumption has been inconsistently associated with breast cancer risk. Recent studies suggest that genetic polymorphisms of glutathione S-transferases (GSTs) may modify this relation. To determine if breast cancer risk is associated with GSTM1 and GSTT1 genetic polymorphisms, and to evaluate the effect modification between GST genotypes and alcohol consumption in the risk of breast cancer, we conducted a case-control study in the state of Connecticut in the period 1998 and 2001. Cases were histologically confirmed, incident breast cancer patients in New Haven County, CT. Controls were randomly selected from women histologically confirmed to be without breast cancer. The study results show that, while GSTM1 genotypes were not associated with breast cancer risk, GSTT1-null genotype was associated with a significant 90% increased risk for postmenopausal women (OR=1.9, 95% CI 1.2-3.0). Analysis by GST genotypes and alcohol consumption shows that GSTM1A ever-drinking women had a 2.5-fold (OR=2.5, 95% CI 1.1-5.5) increased risk of breast cancer compared to the GSTM1A never-drinkers, and the risk increases with duration and daily amount of alcohol consumption. Postmenopausal women with GSTT1-null genotype, who consumed a lifetime of >250 kg of spirit-equivalents, had an almost seven-fold increased risk (OR=6.8, 95% CI 1.4-33.9), and drinking commencing at younger ages appears to carry a higher risk. An OR of 8.2 (95% CI 1.2-57.4) was observed for those with GSTM1A, and GSTT1-null genotypes who had consumed a lifetime of >250 kg of spirit-equivalents. In conclusion, alcohol consumption may increase breast cancer risk among those who carry susceptible GST genotypes.

Use of hair colouring products and breast cancer risk: a case-control study in Connecticut

This case-control study was designed to test the hypothesis that the risk of breast cancer varies by type and colour of the hair colouring products used. A total of 608 cases and 609 controls were included in the study. We found no increased risk associated with the overall use of hair dye products or exclusive use of permanent or temporary types of hair dye products. Among those who reported to have exclusively used semi-permanent types of hair colouring products, some of the ORs were elevated. However, none of the ORs related to age at first use, duration of use, total number of applications, and years since first use, was statistically significant. There was also no increased risk of breast cancer associated with exclusive use of dark or light hair colouring products, or use of mixed types or colours of hair dye products. We also found no increased risk of breast cancer associated with hair dye use based on an individual's reason for using a hair colouring product, such as to cover grey or to change natural hair colour. These data suggest that the use of hair colouring products does not have a major impact on the risk of breast cancer.

Occupation and risk of non-Hodgkin's lymphoma and chronic lymphocytic leukemia

To investigate the association between occupation and the risk of non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL), and to test whether the associations may vary by histological type of NHL, we analyzed data from two population-based, case-control studies of NHL performed in Kansas and Nebraska. A total of 555 incident NHL cases, 56 CLL cases, and 2380 population-based controls were included in the analysis. Information on occupation and other confounding factors was collected through telephone interviews. Study pathologists reviewed slides of tumor tissues in all cases. In men, we found an increased risk of NHL and CLL for those working in agricultural, forestry, and logging industries (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.2 to 2.1). The OR was 1.9 (95% CI, 1.4 to 2.6) for those producing crops. An increased risk was also observed for industries involving metalworking machinery and equipment (OR, 8.4; 95% CI, 1.4 to 50.6), motor vehicles and motor vehicle equipment (OR, 4.2; 95% CI, 1.3 to 13.9), and telephone communications (OR, 3.1; 95% CI, 1.2 to 8.0), and for teachers (OR, 2.5; 95% CI, 1.0 to 6.5), farmers (OR, 2.0; 95% CI, 1.5 to 2.8), and welders and solderers (OR, 2.9; 95% CI, 1.2 to 6.9). The risks for these associations increased by duration of employment and seem to vary by histological type. Work in the printing and publishing industry was also associated with an increased risk of NHL among women. These data suggest that the workers employed in these industries or occupations experienced an increased risk of NHL and CLL, and the risks associated with these industries or occupations may vary by histological type of NHL.

Test-retest reliability of an icon/calendar-based questionnaire used to assess occupational history

BACKGROUND

Self-reported work histories can be critical for both epidemiologic and clinical purposes. However, the complexity of some work histories, such as those of migrant farm workers, can hamper recall, resulting in inaccurate reporting. Memory aids may reduce such error. This study assesses the reliability of work histories collected using such aids in the form of an icon/calendar-based questionnaire.

METHODS

Thirty-one males engaged in farmwork and other manual labor for a median 28 years (range: 10-64) were interviewed twice, 8-14 months apart, about their lifetime employment. In each interview, subjects were asked about important life events, which were recorded with icons on a calendar. They were then asked to recount their work history, including for each job the tasks, crops or products handled, starting and ending dates, and location. This information was recorded, job-by-job, on the calendar with icons.

RESULTS

Interquestionnaire agreement of cumulative reported employment duration (as measured by the correlation coefficient) was moderate to high across all time periods for certain crops (e.g., r = 0.69-0.92 for apple-related work), by location (e.g., r = 0.76-0.95 for Washington State), and for agricultural work in general (r = 0.67-0.94), but was lower for specific tasks. Agreement of job counts was high for total work history for certain crops (e.g., r = 0.93 for apple-related work), by location (e.g., r = 0.90 for Washington State), and for agricultural work in general (r = 0.89), but paradoxically decreased with proximity to the interview date. Agreement of both measures tended to be highest for those tasks and crops in which subjects reported spending the most time. Categorization of subjects into tertiles on the basis of either cumulative duration or counts produced results similar to those observed for job counts.

CONCLUSIONS

The icon-calendar questionnaire is an effective tool for estimating cumulative duration of certain work categorizations among subjects with complex work histories.

Determining the probability of pesticide exposures among migrant farmworkers: results from a feasibility study

BACKGROUND

Migrant and seasonal farmworkers are exposed to pesticides through their work with crops and livestock. Because workers are usually unaware of the pesticides applied, specific pesticide exposures cannot be determined by interviews. We conducted a study to determine the feasibility of identifying probable pesticide exposures based on work histories.

METHODS

The study included 162 farm workers in seven states. Interviewers obtained a lifetime work history including the crops, tasks, months, and locations worked. We investigated the availability of survey data on pesticide use for crops and livestock in the seven pilot states. Probabilities of use for pesticide types (herbicides, insecticides, fungicides, etc.) and specific chemicals were calculated from the available data for two farm workers. The work histories were chosen to illustrate how the quality of the pesticide use information varied across crops, states, and years.

RESULTS

For most vegetable and fruit crops there were regional pesticide use data in the late 1970s, no data in the 1980s, and state-specific data every other year in the 1990s. Annual use surveys for cotton and potatoes began in the late 1980s. For a few crops, including asparagus, broccoli, lettuce, strawberries, plums, and Christmas trees, there were no federal data or data from the seven states before the 1990s.

CONCLUSIONS

We conclude that identifying probable pesticide exposures is feasible in some locations. However, the lack of pesticide use data before the 1990s for many crops will limit the quality of historic exposure assessment for most workers.