Multiple myeloma and farming. A systematic review of 30 years of research. Where next?

Multiple myeloma

Multiple myeloma (MM) is a haematological lymphoid malignancy involving tumoural plasma cells and is usually characterized by the presence of a monoclonal immunoglobulin protein. MM is the second most common haematological malignancy, with an increasing global incidence. It remains incurable because most patients relapse or become refractory to treatments. MM is a genetically complex disease with high heterogeneity that develops as a multistep process, involving acquisition of genetic alterations in the tumour cells and changes in the bone marrow microenvironment. Symptomatic MM is diagnosed using the International Myeloma Working Group criteria as a bone marrow infiltration of ≥10% clonal plasma cells, and the presence of at least one myeloma-defining event, either standard CRAB features (hypercalcaemia, renal failure, anaemia and/or lytic bone lesions) or biomarkers of imminent organ damage. Younger and fit patients are considered eligible for transplant. They receive an induction, followed by consolidation with high-dose melphalan and autologous haematopoietic cell transplantation, and maintenance therapy. In older adults (ineligible for transplant), the combination of daratumumab, lenalidomide and dexamethasone is the preferred option. If relapse occurs and requires further therapy, the choice of therapy will be based on previous treatment and response and now includes immunotherapies, such as bi-specific monoclonal antibodies and chimeric antigen receptor T cell therapy.

Multiple Myeloma and Occupational Risk Factors: A Narrative Review

Multiple Myeloma (MM) is a neoplastic hematologic disorder caused by the excessive proliferation of plasma cells and leads to bone lesions, anemia, and kidney failure. No definite etiology has been proposed for MM, but several environmental and genetic risk factors have been implicated so far. Exposure to pesticides, benzene, and organic solvents like methyl chloride have been considered a potential risk factor. Asbestos, ionizing radiation, and wood dust exposure have also been associated with MM. As MM is a relatively rare condition, the number of studies is insufficient, and in many studies, only a few study participants recall exposure to any agents. Therefore, establishing a definite risk factor is cumbersome and further studies with large study samples are needed. By recognizing these occupational risk factors, clinicians can encourage employees to reduce their exposure as more as possible and implement precautionary measures. In this review, we highlighted the current research on the potential association between occupational exposures and MM. Because of these studies, new regulations with the goal of occupational exposure reduction are anticipated in the future.

Alcohol and tobacco use and risk of multiple myeloma: A case-control study

Multiple myeloma (MM) is the second most common hematological cancer and causes significant mortality and morbidity. Knowledge regarding modifiable risk factors for MM remains limited. This analysis of an Australian population-based case-control family study investigates whether smoking or alcohol consumption is associated with risk of MM and related diseases. Incident cases (n = 789) of MM were recruited via cancer registries in Victoria and New South Wales. Controls (n = 1,113) were either family members of cases (n = 696) or controls recruited for a similarly designed study of renal cancers (n = 417). Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional multivariable logistic regression. Heavy intake (>20 g ethanol/day) of alcohol had a lower risk of MM compared with nondrinkers (OR = 0.68, 95% CI: 0.50-0.93), and there was an inverse dose-response relationship for average daily alcohol intake (OR per 10 g ethanol per day = 0.92, 95% CI: 0.86-0.99); there was no evidence of an interaction with sex. There was no evidence of an association with MM risk for smoking-related exposures (p > 0.18). The associations between smoking and alcohol with MM are similar to those with non-Hodgkin lymphoma. Further research into potential underlying mechanisms is warranted.

Multiple myeloma in Lebanon: Trend analysis, 10-year projections and comparisons to other countries

BACKGROUND

Multiple myeloma (MM) is a common hematological malignancy in aging populations. This study aims to inspect the trends from 2005 to 2016 and future projections of MM in Lebanon and to compare its incidence-rates to other MENA and non-MENA countries.

METHODS

The data concerning MM cases over the studied period was extracted from the National Cancer Registry (NCR) of Lebanon. The online database "Cancer Incidence in Five Continents" was screened and data of other countries were collected. The age-specific and age-standardized incidence rates (ASR(w)) were computed and analyzed using Joinpoint regression. 10 year projections were predicted by employing a logarithmic model.

RESULTS

During the time period 2005-2016, MM was significantly more common in males. Both genders had a cancer peak in patients older than 75 years. MM demonstrated a significantly increasing trend in both genders over the 12 years of study. Compared to other countries in the MENA region, Lebanon ranked first in females and second in males, while it came among the lowest when compared to randomly selected developed countries from non-MENA regions. Projecting to 2026, incidence rates of MM in Lebanon are expected to rise in both males and females.

CONCLUSION

Incidence of MM in Lebanon is continually rising. The elderly population, especially males, is much more affected than the younger one. Different risk factors, specifically obesity and toxic exposures, can explain the escalating burden of MM among the population. A collaboration of efforts between the government and health organization is expected for an effective disease control.

Cancer incidence in agricultural workers: Findings from an international consortium of agricultural cohort studies (AGRICOH)

BACKGROUND

Agricultural work can expose workers to potentially hazardous agents including known and suspected carcinogens. This study aimed to evaluate cancer incidence in male and female agricultural workers in an international consortium, AGRICOH, relative to their respective general populations.

METHODS

The analysis included eight cohorts that were linked to their respective cancer registries: France (AGRICAN: n = 128,101), the US (AHS: n = 51,165, MESA: n = 2,177), Norway (CNAP: n = 43,834), Australia (2 cohorts combined, Australian Pesticide Exposed Workers: n = 12,215 and Victorian Grain Farmers: n = 919), Republic of Korea (KMCC: n = 8,432), and Denmark (SUS: n = 1,899). For various cancer sites and all cancers combined, standardized incidence ratios (SIR) and 95% confidence intervals (CIs) were calculated for each cohort using national or regional rates as reference rates and were combined by random-effects meta-analysis.

RESULTS

During nearly 2,800,000 person-years, a total of 23,188 cancers were observed. Elevated risks were observed for melanoma of the skin (number of cohorts = 3, meta-SIR = 1.18, CI: 1.01-1.38) and multiple myeloma (n = 4, meta-SIR = 1.27, CI: 1.04-1.54) in women and prostate cancer (n = 6, meta-SIR = 1.06, CI: 1.01-1.12), compared to the general population. In contrast, a deficit was observed for the incidence of several cancers, including cancers of the bladder, breast (female), colorectum, esophagus, larynx, lung, and pancreas and all cancers combined (n = 7, meta-SIR for all cancers combined = 0.83, 95% CI: 0.77-0.90). The direction of risk was largely consistent across cohorts although we observed large between-cohort variations in SIR for cancers of the liver and lung in men and women, and stomach, colorectum, and skin in men.

CONCLUSION

The results suggest that agricultural workers have a lower risk of various cancers and an elevated risk of prostate cancer, multiple myeloma (female), and melanoma of skin (female) compared to the general population. Those differences and the between-cohort variations may be due to underlying differences in risk factors and warrant further investigation of agricultural exposures.

Occupational Exposure and Multiple Myeloma Risk: An Updated Review of Meta-Analyses

The precise etiology of multiple myeloma remains elusive, but both genetic and environmental factors have been suggested to contribute to disease risk. Several occupational categories and toxic agents have been implicated as potentially causative, yet findings from the literature are inconsistent. The aim of this review was to summarize and critically comment on the accumulated epidemiological evidence, across published meta-analyses, about the association between occupational exposure and risk of multiple myeloma. Overall, results from eleven meta-epidemiological studies underscore a significantly increased risk for firefighters, hairdressers, and employees exposed to engine exhaust, whereas farming and methylene chloride exposure have been non-significantly correlated with the disease. Further epidemiological studies are of utmost importance whilst emphasis should be placed on occupational hazard surveillance, as such studies will obtain a more accurate picture of disease occurrence in working populations, and will enable both the implementation of preventive actions and the evaluation of their effectiveness.

Lifetime Pesticide Use and Monoclonal Gammopathy of Undetermined Significance in a Prospective Cohort of Male Farmers

BACKGROUND

Farmers have a higher incidence of multiple myeloma, and there is suggestive evidence of an elevated prevalence of its precursor, monoclonal gammopathy of undetermined significance (MGUS), relative to the general population. Pesticide exposures are suspected to play a role; however, the biologic plausibility for associations with multiple myeloma remains unclear.

OBJECTIVES

Our objectives were to examine the prevalence of MGUS and evaluate associations with a wide range of pesticides in a large sample of farmers.

METHODS

We obtained sera and assessed MGUS among 1,638 male farmers ≥ 50  years of age in the Agricultural Health Study (AHS), a prospective cohort in Iowa and North Carolina. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed to estimate associations with MGUS for recent use (within the 12 months before phlebotomy) and cumulative intensity-weighted lifetime days of use of specific pesticides.

RESULTS

The age-standardized MGUS prevalence was significantly elevated among AHS farmers (7.7%) compared with demographically similar men in the National Health and Nutrition Examination Survey (2.8%) or Olmsted County, Minnesota (3.8%; p < 0.001 ). Recent use of permethrin was associated with MGUS [recent use vs. no recent use, OR = 1.82 (95% CI: 1.06, 3.13)], especially among those who had also used it in the past [recent and past use vs. never use, OR = 2.49 (95% CI: 1.32, 4.69)]. High intensity-weighted lifetime use of the organochlorine insecticides aldrin and dieldrin was associated with MGUS relative to those who never used either of these pesticides [OR = 2.42 (95% CI: 1.29, 4.54); p trend = 0.006 ]. We also observed a positive association with high lifetime use of petroleum oil/distillates as an herbicide, as well as an inverse association with fonofos use.

DISCUSSION

This is the largest investigation of MGUS in farmers and the first to identify an association with MGUS for permethrin, a pyrethroid insecticide previously associated with multiple myeloma. Given the continued widespread use of permethrin in various residential and commercial settings, our findings may have important implications for exposed individuals in the general population. https://doi.org/10.1289/EHP6960.

Non-Hodgkin lymphoma risk and organophosphate and carbamate insecticide use in the north American pooled project

Organophosphates and carbamates have been among the most commonly used insecticides, with both agricultural and residential uses. Previous studies have suggested associations of non-Hodgkin lymphoma (NHL) with some of these chemicals; however, many studies have been limited in their ability to evaluate associations with lymphoma subtypes. We evaluated the use of eleven organophosphate and two carbamate insecticides in association with NHL in the North American Pooled Project, which includes data from case-control studies in the United States and Canada (1690 cases/5131 controls). We used unconditional logistic regression adjusting for potential confounders, including use of other pesticides, to estimate odds ratios (OR) and 95% confidence intervals (CI) for associations between these chemicals and NHL overall, and NHL subtypes, i.e., follicular (FL), diffuse large B-cell (DLBCL), small lymphocytic lymphoma (SLL) and others. Ever use of malathion was associated with increased risk of NHL overall (OR = 1.43; 95% CI: 1.14-1.81) compared with never users. Categories using tertiles of duration (<4 yrs., 4-12 yrs., and >12 yrs) also showed a significant exposure-response for increasing years of use of malathion and risk of NHL (OR_<4vsUnex = 1.33 (0.88, 2.03), OR_4-12vsUnex = 1.42 (1.02, 1.96), OR_>12vsUnex = 1.55 (1.05, 2.28, p-trend < 0.01)). In addition, malathion use was statistically significantly associated with FL (OR = 1.58; 95% CI: 1.11-2.27) and DLBCL (OR = 1.61; 95% CI: 1.16-2.22) while there were no apparent associations with SLL or other subtypes, the p-value for heterogeneity across subtypes, however, was not significant. These results support previous studies suggesting an association between insecticide use and NHL overall, and provide new information on associations with NHL subtypes.

Multiple myeloma epidemiology and patient geographic distribution in Canada: A population study

BACKGROUND

Multiple myeloma (MM) is a malignancy of mature plasma cells. Environmental risk factors identified for this malignancy, among others, include farming and exposure to pesticides.

METHODS

Using 3 independent population-based databases (the Canadian Cancer Registry, le Registre Québécois du Cancer, and Canadian Vital Statistics), this study analyzed patients' clinical characteristics and the incidence, mortality, and geographic distribution of MM cases in Canada during 1992-2015.

RESULTS

In total, ~32,065 patients were identified, and 53.7% were male. The mean age at the time of diagnosis was 70 ± 12.1 years. The average incidence rate in Canada was 54.29 cases per million individuals per year, and linear regression modeling showed a steady rise in the annual rate of 0.96 cases per million individuals per year. At the provincial level, Quebec and Ontario had significantly higher incidence rates than the rest of Canada. An analysis of individual municipalities and postal codes showed lower incidence rates in large metropolitan areas and in high-latitude regions of the country, whereas high incidence rates were observed in smaller municipalities and rural areas. Land use analysis demonstrated increased density of crop farms and agricultural industries in high-incidence areas. A comparison with the available data from 2011-2015 showed several consistent trends at provincial, municipal, and regional levels.

CONCLUSIONS

These results provide a comprehensive analysis of the MM burden in Canada. Large metropolitan cities as well as high-latitude regions were associated with lower MM incidence. Higher incidence rates were noted in smaller cities and rural areas and were associated with increased density of agricultural facilities.

Prospective Investigation of Pesticide Applicators' Health (PIPAH) study: a cohort study of professional pesticide users in Great Britain

PURPOSE

The purpose of the study is to monitor the exposure and health of workers in Great Britain who use pesticides as a part of their job, and to gain a better understanding of the relationship between long-term exposure to pesticides and health.

PARTICIPANTS

Study participants are professional pesticide users who are certified in the safe use of pesticides or who were born before 1965 and apply pesticides under 'grandfather rights'. Overall response rate was 20%; participants are mostly male (98%) and the average age is 54 years, ranging from 17 to over 80 years.

FINDINGS TO DATE

Participants have completed a baseline general questionnaire and three follow-up questionnaires on the use of pesticides. These data will enable investigations into the relationship between occupational pesticide exposure and health outcomes taking into account non-occupational confounding factors.

FUTURE PLANS

There is no set end date for data collection. Recruitment into the cohort will continue, and for the foreseeable future there will be annual pesticide use questionnaires and five yearly follow-up general questionnaires.The intention is to validate the pesticide use questionnaire, and to develop a crop/job exposure matrix (C/JEM) which can be updated regularly. This C/JEM will be able to look at general categories of pesticide, such as insecticides, structurally related pesticides, such as organochlorines, or individual active ingredients. Data collected on use of personal protective equipment and method of application will provide information on how potential exposure to pesticide during application may have been modified. The study will be able to estimate changes in individual pesticide use over time, and to examine the associations between pesticide use and both baseline and long-term health outcomes.The cohort members will be linked to national databases for notification of hospital episode statistics, cancer incidence and mortality for follow-up of health outcomes.

Systematic review and meta-analysis of glyphosate exposure and risk of lymphohematopoietic cancers

This systematic review and meta-analysis rigorously examines the relationship between glyphosate exposure and risk of lymphohematopoietic cancer (LHC) including NHL, Hodgkin lymphoma (HL), multiple myeloma (MM), and leukemia. Meta-relative risks (meta-RRs) were positive and marginally statistically significant for the association between any versus no use of glyphosate and risk of NHL (meta-RR = 1.3, 95% confidence interval (CI) = 1.0-1.6, based on six studies) and MM (meta-RR = 1.4, 95% CI = 1.0-1.9; four studies). Associations were statistically null for HL (meta-RR = 1.1, 95% CI = 0.7-1.6; two studies), leukemia (meta-RR = 1.0, 95% CI = 0.6-1.5; three studies), and NHL subtypes except B-cell lymphoma (two studies each). Bias and confounding may account for observed associations. Meta-analysis is constrained by few studies and a crude exposure metric, while the overall body of literature is methodologically limited and findings are not strong or consistent. Thus, a causal relationship has not been established between glyphosate exposure and risk of any type of LHC.

Carfilzomib: a second-generation proteasome inhibitor for the treatment of multiple myeloma

PURPOSE

The pharmacology, clinical efficacy, safety, cost, dosage and administration, and place in therapy of carfilzomib for the treatment of multiple myeloma (MM) are reviewed.

SUMMARY

Proteasome inhibition in MM has become a cornerstone in treatment regimens. Carfilzomib, a second-generation proteasome inhibitor, has demonstrated efficacy in patients with relapsed or refractory disease who have received at least two prior therapies including bortezomib and an immunomodulatory agent. Carfilzomib is an irreversible inhibitor and binds to a different site than bortezomib on the proteasome. A Phase II study evaluated 266 heavily pretreated patients with relapsed or refractory MM who had received at least two prior therapies, including bortezomib and either thalidomide or lenalidomide. The overall response rate was 23.7%, with a median duration of response of 7.8 months. The median overall survival time was 15.6 months. Carfilzomib has a similar adverse-effect profile to bortezomib, including anemia, thrombocytopenia, fatigue, dyspnea, and nausea; however, it does not result in the development or worsening of peripheral neuropathy. Carfilzomib is infused intravenously over 2-10 minutes for 2 consecutive days every week for three out of four weeks, with a 12-day rest period. Dosing is based on the patient's actual body surface area. Carfilzomib is available in 60-mg vials for single infusion. The total cost for a year of therapy is approximately $155,852.

CONCLUSION

Carfilzomib, a second-generation proteasome inhibitor that irreversibly inhibits the 26S proteasome, has shown efficacy in clinical studies of patients with relapsed or refractory MM, though the drug's role in the management of MM is not yet clear.

Risk Factors for Multiple Myeloma: A Systematic Review of Meta-Analyses

The epidemiology of multiple myeloma (MM) is an increasingly investigated field, with many controversies. This systematic review aims to synthesize meta-analyses examining risk factors for MM so as to provide a comprehensive, parsimonious summary of the current evidence. Eligible meta-analyses were sought in PubMed adopting a predefined algorithm, without any restriction of publication language; end-of-search date was October 10, 2014. The selection of eligible studies and data extraction were performed by working in pairs, independently and blindly to each other; in case of disagreement, consensus with the whole team was reached. Among the 22 ultimately included meta-analyses, 9 examined occupational factors, 4 assessed aspects of lifestyle (smoking, alcohol, body mass index), 5 evaluated the presence of other diseases, and 4 addressed genetic factors as potential risk factors of MM. A vast compendium of significant associations arose, including farming, occupation as a firefighter, occupation as a hairdresser, exposures to chemicals or pesticides, overweight and obesity, patterns of alcohol intake, pernicious anemia, ankylosing spondylitis, gene promoter methylation, and polymorphisms. In conclusion, MM is a multifactorial disease, encompassing a wide variety of risk factors that span numerous life aspects. Further accumulation of evidence through meta-analyses is anticipated in this rapidly growing field.

Multiple myeloma and glyphosate use: a re-analysis of US Agricultural Health Study (AHS) data

A previous publication of 57,311 pesticide applicators enrolled in the US Agricultural Health Study (AHS) produced disparate findings in relation to multiple myeloma risks in the period 1993-2001 and ever-use of glyphosate (32 cases of multiple myeloma in the full dataset of 54,315 applicators without adjustment for other variables: rate ratio (RR) 1.1, 95% confidence interval (CI) 0.5 to 2.4; 22 cases of multiple myeloma in restricted dataset of 40,719 applicators with adjustment for other variables: RR 2.6, 95% CI 0.7 to 9.4). It seemed important to determine which result should be preferred. RRs for exposed and non-exposed subjects were calculated using Poisson regression; subjects with missing data were not excluded from the main analyses. Using the full dataset adjusted for age and gender the analysis produced a RR of 1.12 (95% CI 0.50 to 2.49) for ever-use of glyphosate. Additional adjustment for lifestyle factors and use of ten other pesticides had little effect (RR 1.24, 95% CI 0.52 to 2.94). There were no statistically significant trends for multiple myeloma risks in relation to reported cumulative days (or intensity weighted days) of glyphosate use. The doubling of risk reported previously arose from the use of an unrepresentative restricted dataset and analyses of the full dataset provides no convincing evidence in the AHS for a link between multiple myeloma risk and glyphosate use.

The Biomarkers of Exposure and Effect in Agriculture (BEEA) Study: Rationale, Design, Methods, and Participant Characteristics

Agricultural exposures including pesticides, endotoxin, and allergens have been associated with risk of various cancers and other chronic diseases, although the biological mechanisms underlying these associations are generally unclear. To facilitate future molecular epidemiologic investigations, in 2010 the study of Biomarkers of Exposure and Effect in Agriculture (BEEA) was initiated within the Agricultural Health Study, a large prospective cohort in Iowa and North Carolina. Here the design and methodology of BEEA are described and preliminary frequencies for participant characteristics and current agricultural exposures are reported. At least 1,600 male farmers over 50 years of age will be enrolled in the BEEA study. During a home visit, participants are asked to complete a detailed interview about recent agricultural exposures and provide samples of blood, urine, and (since 2013) house dust. As of mid-September 2014, in total, 1,233 participants have enrolled. Most of these participants (83%) were still farming at the time of interview. Among those still farming, the most commonly reported crops were corn (81%) and soybeans (74%), and the most frequently noted animals were beef cattle (35%) and hogs (13%). There were 861 (70%) participants who reported occupational pesticide use in the 12 months prior to interview; among these participants, the most frequently noted herbicides were glyphosate (83%) and 2,4-D (72%), and most commonly reported insecticides were malathion (21%), cyfluthrin (13%), and permethrin (12%). Molecular epidemiologic investigations within BEEA have the potential to yield important new insights into the biological mechanisms through which these or other agricultural exposures influence disease risk.

Multiple myeloma and occupation: a pooled analysis by the International Multiple Myeloma Consortium

OBJECTIVE

We investigated occupational risk of multiple myeloma (MM) in a pooled analysis of five international case-control studies.

METHODS

We calculated the odds ratio and its 95% confidence interval for selected occupations with unconditional regression analysis in 1959 MM cases and 6192 controls, by pooling study-specific risks using random-effects meta-analysis. Exposure to organic solvents was assessed with a job-exposure matrix (JEM).

RESULTS

Gardeners and nursery workers combined, most likely exposed to pesticides, showed a 50% increase in risk (OR = 1.50, 95% CI 0.9-2.3), while other farming jobs did not. Metal processors (OR = 1.55, 95% CI 0.9-2.3), female cleaners (OR = 1.32, 95% CI 1.0-1.8), and high level exposure to organic solvents (OR = 1.38, 95% CI 0.96-1.8) also showed moderately increased risks.

CONCLUSIONS

Additional case-control studies of MM aetiology are warranted to further investigate the nature of the repeatedly reported increase in MM risk in several occupational groups.

Polymorphisms in regulators of xenobiotic transport and metabolism genes PXR and CAR do not affect multiple myeloma risk: a case-control study in the context of the IMMEnSE consortium

The exposure to pesticides and toxic compounds in xenobiotic transport and metabolism genes has been shown to affect risk of developing multiple myeloma (MM). Therefore, we hypothesized that genetic variations in xenobiotic transport and metabolism regulator genes PXR (NR1I2) and CAR (NR1I3) could determine a difference in MM susceptibility. Ten tagging single-nucleotide polymorphisms (SNPs) for PXR and seven for the CAR genes were selected and genotyped in 627 MM cases and 883 controls collected in the context of the International Multiple Myeloma rESEarch (IMMEnSE) consortium. None of the 17 SNPs investigated showed significant association with MM risk either alone or when combined in haplotypes. Significant SNP-SNP interactions were not found, neither with 58 previously genotyped polymorphisms in ABC transporters. We can therefore exclude that common genetic variants in the xenobiotic transport and metabolism regulator genes PXR and CAR affect MM risk.

Multiple Myeloma and lifetime occupation: results from the EPILYMPH study

Background

The EPILYMPH study applied a detailed occupational exposure assessment approach to a large multi-centre case–control study conducted in six European countries. This paper analysed multiple myeloma (MM) risk associated with level of education, and lifetime occupational history and occupational exposures, based on the EPILYMPH data set.

Methods

277 MM cases and four matched controls per each case were included. Controls were randomly selected, matching for age (+/− 5 years), centre and gender. Lifetime occupations and lifetime exposure to specific workplace agents was obtained through a detailed questionnaire. Local industrial hygienists assessed likelihood and intensity for specific exposures. The odds ratio and 95% confidence intervals (OR, 95% CI) were calculated for level of education, individual occupations and specific exposures. Unconditional logistic regression models were run for individual occupations and exposures.

Results

A low level of education was associated with MM OR=1.68 (95% CI 1.02-2.76). An increased risk was observed for general farmers (OR=1.77; 95% CI 1.05-2.99) and cleaning workers (OR=1.69; 95% CI 1.04-2.72) adjusting for level of education. Risk was also elevated, although not significant, for printers (OR=2.06; 95% CI 0.97-4.34). Pesticide exposure over a period of ten years or more increased MM risk (OR=1.62; 95% CI 1.01-2.58).

Conclusion

These results confirm an association of MM with farm work, and indicate its association with printing and cleaning. While prolonged exposure to pesticides seems to be a risk factor for MM, an excess risk associated with exposure to organic solvents could not be confirmed.

Occupational and environmental exposures among Alaska Native and American Indian people living in Alaska and the Southwest United States

Most occupational and environmental research describes associations between specific occupational and environmental hazards and health outcomes, with little information available on population-level exposure, especially among unique subpopulations. The authors describe the prevalence of self-reported lifetime exposure to nine occupational and environmental hazards among 11,326 American Indian and Alaska Native (AI/AN) adults enrolled in the Education and Research Towards Health (EARTH) Study in the Southwest U.S. and Alaska. The top three hazards experienced by AI/AN people in Alaska were petroleum products, military chemicals, and asbestos. The top three hazards experienced by AI/AN living in the Southwest U.S. were pesticides, petroleum, and welding/silversmithing. The study described here found that male sex, lower educational attainment, AI/AN language use, and living in the Southwest U.S. (vs. Alaska) were all associated with an increased likelihood of hazard exposure. The authors' study provides baseline data to facilitate future exposure-response analyses. Future studies should measure dose and duration as well as environmental hazards that occur in community settings.

Poultry and livestock exposure and cancer risk among farmers in the agricultural health study

PURPOSE

The purpose of this study is to evaluate cancer risk associated with raising animals as commodities, which is associated with a variety of exposures, such as infectious agents and endotoxins.

METHODS

Information was available for 49,884 male farmers in the Agricultural Health Study, who reported livestock and poultry production at enrollment (1993-1997). Cancer incidence data were obtained through annual linkage to state registries. Using Poisson regression analyses, we evaluated whether the number and type of animals raised on the farm impacted cancer risk.

RESULTS

Overall, 31,848 (63.8%) male farmers reported raising any animals. Lung cancer risk decreased with increasing number of livestock on the farm (p trend = 0.04) and with raising poultry (Relative Risk (RR) = 0.6; 95% confidence interval (CI): 0.4-0.97). Raising poultry was associated with an increased risk of colon cancer (RR = 1.4; 95% CI: 0.99-2.0) with further increased with larger flocks (p trend = 0.02). Risk of non-Hodgkin lymphoma was also elevated in those who raised poultry (RR = 1.6; 95% CI: 1.0-2.4), but there was no evidence of increased risk with larger flocks (p trend = 0.5). Raising sheep was associated with a significantly increased risk of multiple myeloma (RR = 4.9; 95% CI: 2.4-12.0). Performing veterinary services increased the risk of Hodgkin lymphoma (RR = 12.2; 95% CI: 1.6-96.3).

CONCLUSIONS

We observed an inverse association between raising poultry and livestock and lung cancer risk and some evidence of increased risk of specific lymphohematopoietic malignancies with specific types of animals and performing veterinary services. Further research into associations between raising animals and cancer risk should focus on identification of etiologic agents.

An update of cancer incidence in the Agricultural Health Study

OBJECTIVE

Our objective is to reevaluate cancer incidence among Agricultural Health Study participants.

METHODS

Standardized incidence ratios (SIRs) and relative standardized ratios were calculated.

RESULTS

A significant excess of prostate cancer was seen for private and commercial applicators (SIR = 1.19, 95% CI 1.14, 1.25 and SIR = 1.28, 95% CI = 1.00, 1.61, respectively). Excesses were observed for lip cancer (SIR = 1.97, 95% CI = 1.02, 3.44) and multiple myeloma (SIR = 1.42, 95% CI = 1.00, 1.95) among private applicators from North Carolina and for marginal zone lymphoma among Iowa spouses (SIR = 2.34, 95% CI = 1.21, 4.09).

CONCLUSIONS

Although lower rates of smoking and increased physical activity probably contribute to the lower overall cancer incidence, agricultural exposures including pesticides, viruses, bacteria, sunlight, and other chemicals may increase risks for specific cancer sites.