Occupational and environmental risk factors of the myelodysplastic syndromes in the North of France

[Environmental and occupational risk factors for myelodysplastic syndrome]

Chemotherapy and radiotherapy for a previous cancer can lead to subsequent myelodysplastic syndrome (MDS). However, these therapy-related cases are hypothesized to explain only 5 % of diagnosed MDS cases. Environmental or occupational exposure to chemicals or radiations has also been reported to be associated with higher risk of MDS. The present review analyses those studies evaluating the association of MDS with environmental or occupational risk factors. There is sufficient evidence that environmental or occupational exposure to ionizing radiation or benzene can cause MDS. Tobacco smoking is also a sufficiently documented riskfactor for MDS. A positive association has been reported between exposure to pesticides and MDS. However, there is only limited evidence that this association could be causal.

Myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a family of myeloid cancers with diverse genotypes and phenotypes characterized by ineffective haematopoiesis and risk of transformation to acute myeloid leukaemia (AML). Some epidemiological data indicate that MDS incidence is increasing in resource-rich regions but this is controversial. Most MDS cases are caused by randomly acquired somatic mutations. In some patients, the phenotype and/or genotype of MDS overlaps with that of bone marrow failure disorders such as aplastic anaemia, paroxysmal nocturnal haemoglobinuria (PNH) and AML. Prognostic systems, such as the revised International Prognostic Scoring System (IPSS-R), provide reasonably accurate predictions of survival at the population level. Therapeutic goals in individuals with lower-risk MDS include improving quality of life and minimizing erythrocyte and platelet transfusions. Therapeutic goals in people with higher-risk MDS include decreasing the risk of AML transformation and prolonging survival. Haematopoietic cell transplantation (HCT) can cure MDS, yet fewer than 10% of affected individuals receive this treatment. However, how, when and in which patients with HCT for MDS should be performed remains controversial, with some studies suggesting HCT is preferred in some individuals with higher-risk MDS. Advances in the understanding of MDS biology offer the prospect of new therapeutic approaches.

Agent Orange and dioxin-induced myeloid leukemia: a weaponized vehicle of leukemogenesis

Agent Orange (AO) was the dominant weaponized herbicide employed by the United States (US) military during the Vietnam war. AO, however, was found to be regularly contaminated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic dioxin known; furthermore, AO was commonly diluted in the field with other aromatic hydrocarbons to assist with delivery mechanisms. Unbeknownst to the US military and the millions exposed, these events have likely contributed to the development of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) that has affected many veterans. Null studies regarding an association between AO exposure and AML/MDS are limited in their methodology and application. The acknowledgement that the known carcinogen TCDD was a contaminant in AO when paired with a strong biological plausibility for its leukemogenicity and an observed increased risk of AML/MDS in TCDD-exposed individuals should suffice to establish causal association and that veterans to whom this might apply should be awarded appropriate indemnity.

Personal history of autoimmune disease and other medical conditions and risk of myelodysplastic syndromes

BACKGROUND

Autoimmune diseases and hematopoietic malignancies are known to cluster within individuals, suggesting intertwined etiologies. A limited number of studies have evaluated pre-existing medical conditions as risk factors for myelodysplastic syndromes (MDS). We evaluated associations between autoimmune disease and other medical conditions and risk of MDS.

METHODS

Cases were identified through the Minnesota Cancer Reporting System. Controls were identified through the Minnesota State driver's license/identification card list. History of autoimmune disease and other medical conditions was based on self-report; proxy interviews were not conducted. Unconditional logistic regression was used to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CI).

RESULTS

We included 395 cases and 694 controls. Cases were significantly more likely to report a diagnosis of any autoimmune disease when compared with controls (aOR=1.41, 95% CI: 1.05-1.89) after adjustment for age, sex, education, NSAID use, exposure to benzene and body mass index. When we evaluated specific autoimmune conditions, a statistically significant association was observed for hypothyroidism (aOR=2.16, 95% CI: 1.39-3.34) and odds ratios were elevated for inflammatory bowel disease (aOR=1.75) and systemic lupus erythematosus (SLE; aOR=3.65), although these associations did not reach statistical significance. Presence of an autoimmune condition did not impact overall survival (p = 0.91).

CONCLUSION

Our results validate previous findings of an association between autoimmune disease and MDS. Further studies are required to determine whether this association is due to shared etiology, treatment for autoimmune diseases, or altered immune surveillance or bone marrow damage caused by the autoimmune condition.

Low-Dose Pesticides Alter Primary Human Bone Marrow Mesenchymal Stem/Stromal Cells through ALDH2 Inhibition

(1) Background: The impact of occupational exposure to high doses of pesticides on hematologic disorders is widely studied. Yet, lifelong exposure to low doses of pesticides, and more particularly their cocktail effect, although poorly known, could also participate to the development of such hematological diseases as myelodysplastic syndrome (MDS) in elderly patients. (2) Methods: In this study, a cocktail of seven pesticides frequently present in water and food (maneb, mancozeb, iprodione, imazalil, chlorpyrifos ethyl, diazinon and dimethoate), as determined by the European Food Safety Authority, were selected. Their in vitro effects at low-doses on primary BM-MSCs from healthy volunteers were examined. (3) Results: Exposure of normal BM-MSCs to pesticides for 21 days inhibited cell proliferation and promoted DNA damage and senescence. Concomitantly, these cells presented a decrease in aldehyde dehydrogenase 2 (ALDH2: mRNA, protein and enzymatic activity) and an increase in acetaldehyde levels. Pharmacological inhibition of ALDH2 with disulfiram recapitulated the alterations induced by exposure to low doses of pesticides. Moreover, BM-MSCs capacity to support primitive hematopoiesis was significantly altered. Similar biological abnormalities were found in primary BM-MSCs derived from MDS patients. (4) Conclusions: these results suggest that ALDH2 could participate in the pathophysiology of MDS in elderly people long exposed to low doses of pesticides.

Environmental and occupational determinants of myelodysplastic syndrome: A case-control study from Pakistan

Background

Myelodysplastic syndromes (MDS) are heterogeneous group of haematopoietic stem cell disorders and have variable reduction in the production of red cells, platelets and mature granulocytes.

Aim

We conducted a case–control study evaluating the environmental and occupational determinants as risk factors of MDS.

Methods

A case–control study was conducted including 150 de novo MDS cases and 450 age and gender‐matched controls. Disease characteristics, sociodemographics and exposure to environmental and occupational determinants were collected through a questionnaire. Chi‐square test was applied to observe association, and binary logistic regression was applied to predict the odds of having MDS.

Results

A total of 600 participants were analysed. Those who were exposed to arsenic (OR 31.81, CI: 19.0–53.0, P‐value: .000), benzene (OR 1.564, CI: 1.07–2.27, P‐value: .01) using natural source of water (OR 3.563, CI: 2.29–5.53, P‐value: .000) and smokers (OR 3.1, P‐value: .000) were more likely to have MDS. Unmarried were less likely to acquire MDS than married (OR 0.239, CI: 0.15–0.36, P‐value: .000), Sindhi speaking were 1.419 times more likely to have MDS than participants speaking other languages. Uneducated participants were more likely to have MDS than educated and powder milk users were more likely to have MDS than dairy milk users.

Conclusion

Our results revealed that arsenic, use of natural source of water and benzene exposure might lead to higher risk of acquiring MDS. This study would be helpful to understand the aetiology of disease in Pakistani population.

The importance of evaluating specific myeloid malignancies in epidemiological studies of environmental carcinogens

INTRODUCTION

Although myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), myeloproliferative neoplasms (MPN) - including chronic myeloid leukemia (CML) - and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) are largely clinically distinct myeloid malignancies, epidemiological studies rarely examine them separately and often combine them with lymphoid malignancies, limiting possible etiological interpretations for specific myeloid malignancies.

METHODS

We systematically evaluated the epidemiological literature on the four chemical agents (1,3-butadiene, formaldehyde, benzene, and tobacco smoking, excluding pharmaceutical, microbial and radioactive agents, and pesticides) classified by the International Agency for Research on Cancer as having sufficient epidemiological evidence to conclude that each causes "myeloid malignancies." Literature searches of IARC Monographs and PubMed identified 85 studies that we critically assessed, and for appropriate subsets, summarized results using meta-analysis.

RESULTS

Only two epidemiological studies on 1,3-butadiene were identified, but reported findings were inadequate to evaluate specific myeloid malignancies. Studies on formaldehyde reported results for AML and CML - and not for MDS or MPN - but reported no increased risks. For benzene, several specific myeloid malignancies were evaluated, with consistent associations reported with AML and MDS and mixed results for CML. Studies of tobacco smoking examined all major myeloid malignancies, demonstrating consistent relationships with AML, MDS and MPN, but not with CML.

CONCLUSIONS

Surprisingly few epidemiological studies present results for specific myeloid malignancies, and those identified were inconsistent across studies of the same exposure, as well as across chemical agents. This exercise illustrates that even for agents classified as having sufficient evidence of causing "myeloid malignancies," the epidemiological evidence for specific myeloid malignancies is generally limited and inconsistent. Future epidemiological studies should report findings for the specific myeloid malignancies, as combining them post hoc - where appropriate - always remains possible, whereas disaggregation may not. Furthermore, combining results across possibly discrete diseases reduces the chances of identifying important malignancy-specific causal associations.

An update on treatment of higher risk myelodysplastic syndromes

INTRODUCTION

Myelodysplastic syndromes (MDS) are clonal stem cell disorders mostly affecting the elderly. They are classified into lower and higher risk MDS according to prognostic scoring systems. In higher risk patients, treatments should aim to modify the disease course by avoiding progression to acute myeloid leukemia and, therefore, to improve survival. Areas covered: Stem cell transplantation remains the only curative treatment when feasible, but this concerns a small minority of patients. Treatment is principally based on hypomethylating agents (HMAs). Our understanding of MDS biology has led to the development of drugs targeting key cellular processes such as apoptosis or posttranslational protein changes, microenvironment-like immunotherapy, and gene mutations. Currently, new drugs are mainly being tested in combination with HMAs in several clinical trials. Expert commentary: Significant advances have been made in the field of MDS, especially in molecular typing, which are improving our ability to offer patients risk-adapted therapies. The current challenge in the management of higher risk MDS is to improve outcome by combining classical HMAs with novel drugs.

FLT3-ITD, NPM1, and DNMT3A Gene Mutations and Risk Factors in Normal Karyotype Acute Myeloid Leukemia and Myelodysplastic Syndrome Patients in Upper Northern Thailand

Objective:

Approximately 40-45% of AML and MDS patients have a cytogenetically normal karyotype (CN-AML and CN-MDS). The frequency and types of gene mutations in these cases may differ among various populations. The objective of this study was to identify frequencies and types of FLT3-ITD, NPM1, and DNMT3A mutations, and associations of them with clinical data and risk factors in CN-AML and CN-MDS cases in upper Northern Thailand.

Methods:

Bone marrow samples of 40 CN-AML and 60 CN-MDS patients were analyzed for gene mutations by direct sequencing. In addition, data for potential risk factors were obtained for comparison.

Results:

Frequencies of FLT3-ITD, NPM1, and DNMT3A mutations were 25.0%, 17.5%, and 10.0%, respectively in CN-AML, but all zero in CN-MDS cases. NPM1 mutations were found at a median age older than the wild type (58 vs 47 years) while DNMT3A mutations were associated with an increase in the white blood cell count. In all patients, factors for the mutations of these three genes included age ≤ 60 years, and a history of hypertension.

Conclusion:

When considering mutations in only normal karyotype patients, the frequency of FLT3-ITD, NPM1, DNMT3A mutations in CN-AML patients in upper Northern Thailand were found to occur at lower rates than in Western patients and to differ from other Asian populations including parts of Thailand. No mutations were observed in CN-MDS cases. Some types of gene mutations differed from previous studies, possibly attributable to differences in geography, lifestyle and genetic backgrounds. Links with age ≤ 60 years and history of hypertension were found. Investigation of these three genes in an intermediate risk group with a normal karyotype is useful for a better understanding of molecular leukemogenetic steps in CN-AML and CN-MDS patients and may be beneficial for planning treatment and prevention in the population of upper Northern Thailand.

Clinical, hematological, and cytogenetic profile of adult myelodysplastic syndrome in a tertiary care center

BACKGROUND

Myelodysplastic syndrome (MDS), a disorder of clonal hematopoiesis, is an important clinical entity, but most of the studies available are conducted among the Western population. Its etiological factors and clinicohematological profile in the Indian population are quite diverse. The information regarding its prognostic factors and cytogenetics is very scarce.

OBJECTIVES

(1) To assess the clinicohematological profile, cytogenetics, prognostic factors, and outcome of MDS and (2) to study its progression to acute myeloid leukemia (AML) in the selected patients over the study period.

METHODS

A prospective observational study was performed with patients from Department of Medicine and Hematology, Government Medical College, Kozhikode, who were diagnosed with MDS within the study period (from 1 January 2014 to 31 July 2015). Secondary causes of dysplasia were excluded. In possible cases, the international prognostic scoring system was followed. These patients were followed up for an additional 6 months to assess the progression of MDS to AML based on symptoms, signs, hemogram, or repeat peripheral smear/bone marrow studies.

RESULTS

Of the 60 patients, 73% were aged >60 years. Disease was common in males, with a male:female ratio of 7:3. Thirty-five percent of the patients were working in agricultural and allied fields and had pesticide exposure. Patients with prior radiation exposure had significant association with adverse outcome. Fatigue was the prominent symptom and was reported by 90% of the patients. Blasts were >5% in peripheral smear; bone marrow cytopenia and dysplasia at the time of diagnosis had significant association with risk of transforming to AML. Refractory anemia (RA), observed in 22 patients, was the most common type of MDS. Most of the patients with RA with excess blasts type-1 and RA with excess blasts type-2 transformed to AML, and the association was statistically significant. Deletion of short arm of fifth chromosome (5q deletion) was detected in 11 patients. All of them showed good response to treatment with lenalidomide and had a favorable outcome.

CONCLUSION

This study highlights the various etiological factors, and the clinical profile of MDS seen in the Indian population. Cytogenetic analysis and application of the international prognostic scoring system has a significant bearing on the outcome, as exemplified by the response to lenalidomide in patients with 5q deletion. This study also indicates that proper diagnostic and prognostic assessment is necessary to institute appropriate therapeutic options.

Occupational, dietary, and other risk factors for myelodysplastic syndromes in Western Greece

PURPOSE

We have observed an increasing incidence of myelodysplastic syndromes (MDS) in the geographic area of Western Greece during the past two decades. The objective of this study was to investigate potential risk factors for the manifestation of MDS in this area of Greece.

METHODS

A hospital-based case-control study was conducted in the public hospitals of the region. Participants were interviewed based on a questionnaire regarding demographics, occupational exposures, smoking, alcohol consumption, dietary, and domestic factors.

RESULTS

A total of 228 individuals (126 cases, 102 controls) were recruited in this study. Univariate analysis showed that risk of MDS was associated with a family history of hematologic malignancy or solid tumor, exposure to pesticides, insecticides, herbicides, increased weekly intake of meat and eggs, and increased alcohol intake, whereas fruit intake had a protective effect. Analysis by pesticide ingredient showed a weak association of exposure to paraquat and glyphosate with the occurrence of MDS. Multivariate analysis showed that independent risk factors for the manifestation of MDS were family history of solid tumor (OR 2.47, 95% CI 1.32-4.65), meat intake for ≥5 days/week (OR 2.67, 95% CI 1.05-6.80) and exposure to pesticides (OR 3.25, 95% CI 1.73-6.11).

CONCLUSIONS

Exposure to pesticides is a major risk factor of MDS in Western Greece. Family history of solid tumor and increased meat intake also appear to play a role in the pathogenesis of MDS. Public health authorities should implement policies to advise and protect farmers from the harmful effects of agrochemicals. Emphasis should also be given to health promotion advice including healthy eating.

Chemical exposures and risk of acute myeloid leukemia and myelodysplastic syndromes in a population-based study

Benzene exposure is one of the few well-established risk factors for myeloid malignancy. Exposure to other chemicals has been inconsistently associated with hematologic malignancies. We evaluated occupational and residential chemical exposures as risk factors for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) using population-based data. AML and MDS cases were identified by the Minnesota Cancer Surveillance System. Controls were identified through the Minnesota driver's license/identification card list. Chemical exposures were measured by self-report. Unconditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CI). We included 265 MDS cases, 420 AML cases and 1388 controls. We observed significant associations between both MDS and AML and benzene (OR = 1.77, 95% CI 1.19, 2.63 and OR = 2.10, 95% CI 1.35, 3.28, respectively) and vinyl chlorides (OR = 2.05, 95% CI 1.15, 3.63 and OR = 2.81, 95% CI 1.14, 6.92). Exposure to soot, creosote, inks, dyes and tanning solutions and coal dust were associated with AML (range ORs = 2.68-4.03), while no association was seen between these exposures and MDS (range ORs = 0.57-1.68). Pesticides and agricultural chemicals were not significantly associated with AML or MDS. Similar results were observed in analyses stratified by sex. In addition to providing risk estimates for benzene from a population-based sample, we also identified a number of other occupational and residential chemicals that were significantly associated with AML; however, all exposures were reported by only a small percentage of cases (≤10%). While chemical exposures play a clear role in the etiology of myeloid malignancy, these exposures do not account for the majority of cases.

Cigarette Smoking and the Risk of Adult Myeloid Disease: A Meta-Analysis

Background

The adult myeloid diseases, myelodysplastic syndrome and acute myeloid leukemia, have been reported to be associated with cigarette smoking, but the results have been conflicting. Previous studies may have ignored the relationship between myelodysplastic syndrome and acute myeloid leukemia, where approximately one-third of myelodysplastic syndrome cases will progress to acute myeloid leukemia, which could induce a serious bias in independent analyses. For the purposes of researching pathogenesis, we suggest that myelodysplastic syndrome and acute myeloid leukemia should be regarded as a single class of adult myeloid disease, and herein assessed the relationship between cigarette smoking and the risk of adult myeloid disease.

Methods

The PubMed, Cochrane Library, EBSCO, and EMBASE databases were systematically searched for reports published from 1990 to 2015. Two authors independently assessed the methodological quality and the extracted data. The odds ratios and adjusted odds ratios (OR), a sensitivity analysis, and the publication bias were analyzed using the CMA v2 (Comprehensive Meta Analysis Version 2) software program.

Results

Twenty-five studies were included in this meta-analysis. The publication dates ranged from 1990 to 2014. The pooled OR in current smokers and ever-smokers showed an increased risk of adult myeloid disease, with ORs of 1.45 (95% CI, 1.30–1.62; p<0.001) and 1.23 (95% CI 1.15–1.32; p<0.001) versus non-smokers, respectively. In the subset analyses, the OR of adult myeloid disease was increased regardless of the form of disease, geographical region, NOS (Newcastle Ottawa Scale) score, and source of controls. The smoking status was divided into <20 and ≥20 cigarettes per day, and these groups had ORs of developing adult myeloid disease of 1.24 (95% CI, 1.09–1.40; p = 0.001) and 1.32 (95% CI, 1.14–1.53; p<0.001), respectively. In the groups divided based on the number of years the subjects had smoked (<20 and ≥20 years), the ORs were 1.05 (95% CI, 0.90–1.23; p = 0.25) and 1.30 (95% CI, 1.16–1.45; p<0.001), respectively. Similarly, <20 and ≥20 pack-years were associated with ORs of 1.15 (95% CI, 1.03–1.29; p = 0.017) and 1.34 (95% CI, 1.18–1.52; p<0.001), respectively.

Conclusions

This meta-analysis, for the first time, combined myelodysplastic syndrome with acute myeloid leukemia to assess the overall risk of adult myeloid disease, and it demonstrated that cigarette smoking is associated with a significantly increased risk of adult myeloid disease.

Myelodysplastic syndromes spatial clusters in disease etiology and outcome

The myelodysplastic syndromes (MDS) are a heterogeneous group of hematopoietic disorders. This study aims to advance the use of spatial modeling in disease etiology and monitoring based on reports on a large population (n = 984) of MDS patients diagnosed in the Eastern United States. The spatial MDS clustering was analyzed using SaTScan, and patient clinical characteristics were analyzed using logistic regression and Cox hazards models adjusting for covariates. One main and five secondary spatial clusters (p-value < 10^-17-10^-7) were identified. Patients living in high vs. low MDS incidence clusters tended to be older (OR_adj = 1.04 [1.004, 1.07]) and smokers (OR_adj = 2.9 [1.1, 7.4]). Mortality was associated with hemoglobin (HR_adj = 0.7 [0.5, 0.9]), neutrophils (HR_adj = 0.7 [0.6, 0.96]), platelets (HR_adj = 0.5 [0.4, 0.7]), and blast (HR_adj = 1.4 [1.1, 1.8]), but not clusters. The results suggest large geographic variations in MDS incidence rates. The biological aggressiveness of the disease is unlikely to be associated with its spatial distribution.

Pesticide exposure as a risk factor for myelodysplastic syndromes: a meta-analysis based on 1,942 cases and 5,359 controls

OBJECTIVE

Pesticide exposure has been linked to increased risk of cancer at several sites, but its association with risk of myelodysplastic syndromes (MDS) is still unclear. A meta-analysis of studies published through April, 2014 was performed to investigate the association of pesticide exposure with the risk of MDS.

METHODS

Studies were identified by searching the Web of Science, Cochrane Library and PubMed databases. Summary odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were calculated using random- or fixed-effect models.

RESULTS

This meta-analysis included 11 case-control studies, all of which demonstrated a correlation between pesticide exposure and a statistically significant increased risk of MDS (OR=1.95, 95% CI 1.23-3.09). In subgroup analyses, patients with pesticide exposure had increased risk of developing MDS if they were living in the Europe or Asia and had refractory anemia (RA) or RA with ringed sideroblasts (RARS). Moreover, in the analysis by specific pesticides, increased risk was associated with exposure to insecticides (OR=1.71, 95% CI 1.22-2.40) but not exposure to herbicides or fungicides.

CONCLUSION

This meta-analysis supports the hypothesis that exposure to pesticides increases the risk of developing MDS. Further prospective cohort studies are warranted to verify the association and guide clinical practice in MDS prevention.

Myelodysplastic syndromes

Myelodysplastic syndromes are clonal marrow stem-cell disorders, characterised by ineffective haemopoiesis leading to blood cytopenias, and by progression to acute myeloid leukaemia in a third of patients. 15% of cases occur after chemotherapy or radiotherapy for a previous cancer; the syndromes are most common in elderly people. The pathophysiology involves cytogenetic changes with or without gene mutations and widespread gene hypermethylation at advanced stages. Clinical manifestations result from cytopenias (anaemia, infection, and bleeding). Diagnosis is based on examination of blood and bone marrow showing blood cytopenias and hypercellular marrow with dysplasia, with or without excess of blasts. Prognosis depends largely on the marrow blast percentage, number and extent of cytopenias, and cytogenetic abnormalities. Treatment of patients with lower-risk myelodysplastic syndromes, especially for anaemia, includes growth factors, lenalidomide, and transfusions. Treatment of higher-risk patients is with hypomethylating agents and, whenever possible, allogeneic stem-cell transplantation.

Myelodysplasia: new approaches

The myelodysplastic syndromes (MDS) are a group of clonal hematopoietic disorders characterized by bone marrow failure and a risk of progression to acute myelogenous leukemia (AML). A precise diagnosis is critical, because there is overlap between the clinical and laboratory findings of MDS and other malignant and nonmalignant hematologic disorders. Several prognostic scoring systems (IPSS, WPSS, LR-PSS, and IPSS-R) assess a patient's risk of progression to AML and overall survival. Many patients are elderly, so age and comorbidities are an important consideration. Patients with lower-risk disease are treated with growth factors (erythropoietin stimulating agents and/or G-CSF) and immunomodulatory agents (antithymocyte globulin and/or lenalidomide). Patients with higher-risk disease have a higher risk of progression to AML and are treated with hypomethylating agents (azacitidine or decitabine) and allogeneic stem cell transplantation if appropriate. Recent laboratory studies have increased our understanding of the pathophysiology of this disease. Mutations in genes effecting ribosomes, splicing of RNA and epigenetics have been discovered. It is likely that these breakthroughs will lead to newer classes of targeted therapies against this disease.

A Meta-Analysis of the Relationship between Cigarette Smoking and Incidence of Myelodysplastic Syndromes

BACKGROUND

In recent years, epidemiologic studies have reported controversial results relating cigarette smoking to myelodysplastic syndromes (MDS) risk. A meta-analysis was performed to assess such potential relationship between cigarette smoking and incidence of MDS.

METHODS

A search of literature published before October 2012 for observational studies evaluating the association between cigarette smoking and MDS, returned 123 articles and of these, 14 were selected for this study. The outcomes from these studies were calculated and reported as odds ratios (OR). Quality assessments were performed with the Newcastle-Ottawa Scale. Heterogeneity was evaluated by the I(2) index and source of heterogeneity was detected by sensitivity analyses. Finally, publication bias was assessed through visual inspection of funnel plots and Egger's test.

RESULTS

The pooled OR of developing MDS in ever-smokers was 1.45 (95% CI, 1.25 to 1.68) versus non-smokers. Current and former smokers had increased risks of MDS, with ORs of 1.81 (95% CI, 1.24 to 2.66) and 1.67 (95% CI, 1.42 to 1.96), respectively. In subset analyses, ever-smokers had increased risks of developing MDS if they were living in the United States, or in Europe, female in gender, had refractory anemia (RA)/RA with ringed sideroblasts (RARS) or RA with excess blasts (RAEB)/RAEB in transformation (RAEBt), respectively. Our results demonstrated that the association was stronger in individuals who smoked ≥20 cigarettes/day (OR, 1.62; 95% CI, 1.03 to 2.55) versus those who smoked <20 cigarettes/day (OR, 1.36; 95% CI, 1.13 to 1.64). Moreover, individuals who smoked more than 20 pack-years had increased MDS risk (OR, 1.94; 95% CI, 1.29 to 2.92).

CONCLUSION

Our outcomes show that smoking increases the risk of developing MDS in ever-smokers who are current or former smokers. We also demonstrate here that positive association between cigarette smoking and risk of MDS exists, and occurs in a dose-dependent manner.

What's all the fuss about? facts and figures about bone marrow failure and conditions

The epidemiology of bone marrow failure conditions is not well understood. Although several population-based studies conducted in the last two decades have generated a wealth of information, it is still very challenging to interpret disease incidence and prevalence, particularly due to changes in disease classification, misdiagnosis of patients, frequent underreporting and use of different referent populations to calculate rates. Despite these limitations, the available epidemiologic data have revealed significant ethnic, geographic and clinical differences in disease biology that have implications for prevention and treatment strategies. With advances made in targeted therapies facilitated by identification of molecular biomarkers and increased use of curative bone marrow transplantation approach, the natural history of these disease entities is already changing. The epidemiology of these diseases seems to be the next frontier as knowledge gained about the risk factors and pathobiologic correlates could significantly help in designing patient-specific therapies with improved outcomes.

Critical review and synthesis of the epidemiologic evidence on formaldehyde exposure and risk of leukemia and other lymphohematopoietic malignancies

Purpose

Recent epidemiologic studies indicate elevated risks for some lymphohematopoietic malignancies (LHM) related to formaldehyde exposure. We performed a systematic review of literature to assess the strength and consistency of associations.

Methods

We summarized published literature in the PubMed database of the National Library of Medicine during 1966–2012. Literature was categorized according to study design and population: industrial cohort studies, professional cohort studies, and population-based case–control studies.

Results

Findings from occupational cohort and population-based case–control studies were very inconsistent for LHM, including myeloid leukemia. Apart from some isolated exceptions, relative risks were close to the null, and there was little evidence for dose–response relations for any of the LHM.

Conclusions

At present, there is no consistent or strong epidemiologic evidence that formaldehyde is causally related to any of the LHM. The absence of established toxicological mechanisms further weakens any arguments for causation. To be informative, future epidemiologic research should improve on formaldehyde exposure assessment and apply modern diagnostic schemes for specific LHM.

Alcohol drinking, tobacco smoking and subtypes of haematological malignancy in the UK Million Women Study

BACKGROUND

Previous research suggests associations of lower alcohol intake and higher tobacco consumption with increased risks of haematological malignancy. The prospective Million Women Study provides sufficient power for reliable estimates of subtype-specific associations in women.

METHODS

Approximately 1.3 million middle-aged women were recruited in the United Kingdom during 1996-2001 and followed for death, emigration and cancer registration until 2009 (mean 10.3 years per woman); potential risk factors were assessed by questionnaire. Adjusted relative risks were estimated by Cox regression.

RESULTS

During follow-up, 9162 incident cases of haematological malignancy were recorded, including 7047 lymphoid and 2072 myeloid cancers. Among predominantly moderate alcohol drinkers, higher intake was associated with lower risk of lymphoid malignancies, in particular diffuse large B-cell lymphoma (relative risk 0.85 per 10 g alcohol per day (95% confidence interval 0.75-0.96)), follicular lymphoma (0.86 (0.76-0.98)) and plasma cell neoplasms (0.86 (0.77-0.96)). Among never- and current smokers, higher cigarette consumption was associated with increased risk of Hodgkin lymphoma (1.45 per 10 cigarettes per day (1.22-1.72)), mature T-cell malignancies (1.38 (1.10-1.73)) and myeloproliferative/myelodysplastic disease (1.42 (1.31-1.55)).

CONCLUSION

These findings confirm and extend existing evidence for associations of subtypes of haematological malignancy with two common exposures in women.

Epidemiology of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic stem cell malignancies with significant morbidity and high mortality. The incidence of MDS increases markedly with age, and the disease is most prevalent in individuals who are white and male. It is conservatively estimated that >10,000 new cases of MDS occur in the United States annually, and that ≥ 60,000 individuals with MDS currently reside in the country. With an aging population and an improving awareness of the disease, the documented disease burden is expected to escalate in the near future. Recent studies have identified new or inconsistent etiologic factors that warrant further research. Given the poor survival of individuals with MDS, it is important to identify prognostic factors to better risk-stratify patients for more effective treatment. The relevance of different comorbidities to MDS prognosis and the potential interaction between various comorbidities represents an interesting area of research.

Case-control study of risk factors of myelodysplastic syndromes according to World Health Organization classification in a Chinese population

Risk factors of mydelodysplastic syndromes (MDS) remain largely unknown. We conducted a hospital-based case-control study consisting of 403 newly diagnosed MDS patients according to World Health Organization classification and 806 individually gender and age-matched patient controls from 27 major hospitals in Shanghai, China, to examine relation of lifestyle, environmental, and occupational factors to risk of MDS. The study showed that all MDS (all subtypes combined) risk factors included anti tuberculosis drugs [odds ratio (OR)(adj) = 3.15; 95% confidence interval (CI) = 1.22-8.12] as an independent risk factor, benzene (OR(adj) = 3.73; 95% CI = 1.32-10.51), hair dye use (OR = 1.46; 95% CI = 1.03-2.07), new building and renovations (OR = 1.69; 95% CI = 1.11-2.00), pesticides (OR = 2.16; 95% CI = 1.22-3.82), and herbicides (OR = 5.33; 95% CI = 1.41-20.10) as relative risk factors. Risk factors of MDS subtype refractory cytopenia with multiple dysplasia (RCMD) were benzene (OR(adj) = 5.99; 95% CI = 1.19-30.16) and gasoline (OR(adj) = 11.44; 95% CI = 1.31-100.03) as independent risk factors, and traditional Chinese medicines (OR = 2.17; 95% CI = 1.15-4.07), pesticides (OR = 2.92; 95% CI = 1.37-6.25), and herbicides (OR = 12.00; 95% CI = 1.44-99.67) as relative risk factors. Smoking tobacco was significantly associated with refractory anemia with excess of blasts (RAEB) (OR(adj) = 2.43; 95% CI = 1.02-5.77). Education is shown as an independent protective factor against all MDS (OR(adj) = 0.90; 95% CI = 0.83-0.99) and RCMD (OR(adj) = 0.89; 95% CI = 0.79-0.99). These findings suggest that multiple modifiable behavioral, environmental, and occupational factors play a role in MDS etiology, and various MDS subtypes may have different susceptibility.

The epidemiology of myelodysplastic syndromes

The incidence of the myelodysplastic syndromes (MDS) in the United States is reported as 3.4 per 100,000 people, translating to over 10,000 new diagnoses annually. This figure is considered to be an underestimate as our data capture techniques improve, and probably translates to a prevalence of approximately 60,000 people or more living with the disease. Patients are in their seventh or eighth decades at diagnosis, typically present with cytopenias, and have substantive transfusion requirements. The most common risk factors for developing MDS include advanced age, male gender, previous exposure to chemotherapy or radiation therapy, smoking, or, in rare cases, exposure to industrial chemicals.

Daily practice management of myelodysplastic syndromes in France: data from 907 patients in a one-week cross-sectional study by the Groupe Francophone des Myelodysplasies

BACKGROUND

There is little published information on the everyday clinical management of myelodysplastic syndromes in real world practice.

DESIGN AND METHODS

We conducted a cross-sectional study of all patients with myelodysplastic syndromes attending 74 French centers in a 1-week period for inpatient admission, day-hospital care or outpatient visits.

RESULTS

Nine hundred and seven patients were included; 67.3% had lower-risk myelodysplastic syndromes (International Prognostic Scoring System: low or intermediate-1). Karyotype had been analyzed in 82.5% of the cases and was more often of intermediate or poor risk in patients under 65 years old compared with those who were older. Red blood cell transfusions accounted for as many as 31.4% of the admissions. Endogenous erythropoietin level was less than 500 IU/L in 88% of the patients tested. Erythroid stimulating agents had been or were being used in 36.8% of the lower risk patients, iron chelation in 31% of lower risk patients requiring red blood cell transfusions and lenalidomide in 41% of lower risk patients with del 5q. High-dose chemotherapy, hypomethylating agents, low dose cytarabine and allogeneic stem cell transplantation had been or were being used in 14.8%, 31.1%, 8.8% and 5.1%, respectively, of higher-risk patients.

CONCLUSIONS

Karyotype is now assessed in most patients with myelodysplastic syndromes, and patients under 65 years old may have more aggressive disease. Apart from erythroid-stimulating agents and, in higher-risk myelodysplastic syndromes, hypomethylating agents, specific treatments are used in a minority of patients with myelodysplastic syndromes and red blood cell transfusions still represent the major reason for hospital admission.

Obesity, lifestyle factors, and risk of myelodysplastic syndromes in a large US cohort

The etiology of myelodysplastic syndromes (MDS) is not well understood. The authors examined the relations of obesity and lifestyle factors to MDS in a cohort of 471,799 persons aged 50-71 years who were recruited into the National Institutes of Health-AARP Diet and Health Study, a large US prospective study, in 1995-1996. Incident MDS was diagnosed in 193 persons during 2001-2003. A significant positive association was observed between body mass index (BMI; weight (kg)/height (m)(2)) at baseline and MDS. Compared with persons with a BMI less than 25.0, the hazard ratios for persons with BMIs of 25.0-<30.0 and >or=30.0 were 1.15 (95% confidence interval (CI): 0.81, 1.64) and 2.18 (95% CI: 1.51, 3.17; P for trend < 0.001), respectively. The association was not affected by physical activity, cigarette smoking, or alcohol intake. As reported in previous studies, the risk of MDS was elevated among former smokers (hazard ratio = 1.68, 95% CI: 1.17, 2.41) and current smokers (hazard ratio = 3.17, 95% CI: 2.02, 4.98) as compared with never smokers. Physical activity, alcohol consumption, meat intake, and fruit and vegetable intake did not appear to significantly influence the risk of MDS in this analysis. This prospective investigation of MDS implicates both obesity and smoking as modifiable risk factors.

Risks of myeloid malignancies in patients with autoimmune conditions

Autoimmune conditions are associated with an elevated risk of lymphoproliferative malignancies, but few studies have investigated the risk of myeloid malignancies. From the US Surveillance Epidemiology and End Results (SEER)-Medicare database, 13 486 myeloid malignancy patients (aged 67+ years) and 160 086 population-based controls were selected. Logistic regression models adjusted for gender, age, race, calendar year and number of physician claims were used to estimate odds ratios (ORs) for myeloid malignancies in relation to autoimmune conditions. Multiple comparisons were controlled for using the Bonferroni correction (P<0.0005). Autoimmune conditions, overall, were associated with an increased risk of acute myeloid leukaemia (AML) (OR 1.29) and myelodysplastic syndrome (MDS, OR 1.50). Specifically, AML was associated with rheumatoid arthritis (OR 1.28), systemic lupus erythematosus (OR 1.92), polymyalgia rheumatica (OR 1.73), autoimmune haemolytic anaemia (OR 3.74), systemic vasculitis (OR 6.23), ulcerative colitis (OR 1.72) and pernicious anaemia (OR 1.57). Myelodysplastic syndrome was associated with rheumatoid arthritis (OR1.52) and pernicious anaemia (OR 2.38). Overall, autoimmune conditions were not associated with chronic myeloid leukaemia (OR 1.09) or chronic myeloproliferative disorders (OR 1.15). Medications used to treat autoimmune conditions, shared genetic predisposition and/or direct infiltration of bone marrow by autoimmune conditions, could explain these excess risks of myeloid malignancies.

Keokuk County rural health study: self-reported use of agricultural chemicals and protective equipment

The Keokuk County Rural Health Study is a population-based study of an agricultural community in Iowa. The study includes in-depth evaluations of respiratory disease, injury, and other health outcomes in relation to environmental and occupational exposures. This article reports descriptive findings on pesticide use from among the 1191 participants completing occupational surveys. Fifty-one percent (612) of respondents (farmers and non-farmers) had applied insecticides including lawn and garden chemicals at home during the past year. Thirty-three percent (395) of respondents had personally mixed or applied farm chemicals during their life. One-hundred and four had a current pesticide applicator's license. Information on the specific types of pesticides and protective measures used was obtained for the 144 individuals who had mixed or applied pesticides on farms within the previous year. Of these individuals, 67% worked with fertilizers, 49% used herbicides, 48% used crop insecticides, 28% used crop storage insecticides, 45% applied livestock insecticides, and 9% worked with fungicides. The use of personal protective equipment such as gloves, aprons, and respirators varied depending on the chemical. A substantial proportion did not use gloves even for mixing. Thirty-five percent reported at least one suspected work-related symptom after working with pesticides during the previous year. The lack of differences in protective equipment use between applicators who have completed pesticide applicator training courses and those who have not suggests a need to develop more effective training methods. The increased use of protective equipment when applying odorous agrochemicals suggests that addition of an odorant to more toxic pesticides may be a successful intervention strategy.

Smoking as a risk factor for myelodysplastic syndromes and acute myeloid leukemia and its relation to cytogenetic findings: a case-control study

In this case-control study, interview data on smoking habits were available for 179 de novo cases (116 with cytogenetic data) of acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS). Smoking habits were compared with a pooled set of population controls and hospital controls (diagnosed with malignant melanoma). Each pack-year of smoking increased the risk of MDS with 1.3% (95% CI 0.1-2.6%), corresponding to an estimated excess risk of 71% (95% CI 3-180%) for 40 pack-years. Associations between smoking and the specific aberrations -5/5q-, -7/7q-, and +8 in AML and MDS were indicated but the estimates were imprecise.

Epidemiology of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are one of the most common hematological conditions among the elderly. Differences in disease classification and diagnosis have made population-based studies an arduous endeavor. A variety of risk factors have been linked with increased risk (smoking and exposure to solvents and agrochemicals) or decreased risk of MDS (wine drinking), but the majority of cases remain unexplained. One area that has not been explored is the influence of diet in MDS development. Much still needs to be learned about what causes MDS and the genetic factors that increase susceptibility. Multi-institutional studies with a molecular-epidemiologic approach are necessary to develop a MDS risk predictive model.

Occupational exposure to pesticides and risk of hematopoietic cancers: meta-analysis of case–control studies

OBJECTIVE

In this study we conducted a meta-analysis of 13 case-control studies that examined the occurrence of hematopoietic cancers in pesticide related occupations in order to undertake a qualitative and quantitative evaluation of a possible relationship.

METHODS

Pubmed databases were searched for case-control studies published between 1990 and 2005 investigating the relation between hematopoietic cancers and occupational exposure to pesticides. Fixed and random effect meta-analysis models were used depending on the presence of heterogeneity between studies.

RESULTS

The overall meta-odds ratio obtained after pooling 44 ORs from 13 studies was 1.3 (95% CI: 1.3-1.5). We realized stratified analysis on three different types of hematopoietic cancers (non-Hodgkin lymphoma (NHL), leukemia and multiple myeloma). A significant increased risk of NHL was found (OR = 1.35; 95% CI = 1.2-1.5). Moreover, increased risks of Leukemia (OR = 1.35; 95% CI = 0.9-2) and multiple myeloma (OR = 1.16; 95% CI = 0.99-1.36) were also detected but these results were not statistically significant. Significant heterogeneity existed among the different studies and a publication bias was detected. Therefore, a meta-regression was carried out. Our results showed that a long period of exposure (more than 10 years) provided an increase in the risk of all hematopoietic cancers and for NHL by fractions of 2.18 (95% CI = 1.43-3.35) and 1.65 (95% CI = 1.08-2.51), respectively.

CONCLUSIONS

The overall meta-odds ratio suggests that there is a significantly positive association between occupational exposure to pesticides and all hematopoietic cancers as well as NHL. A major limitation of our meta-analysis is the lack of sufficient data about exposure information and other risk factors for hematopoietic cancer (genetic predisposition, ethnic origin, immunodepression...). In addition, data concerning specific subtypes of hematopoietic cancers are often confusing. Thus, future epidemiological studies should undertake a major effort to assess the identity and the level of pesticides exposure and should control for the most likely potential confounders.

Fluorescence in situ hybridization analysis of 110 hematopoietic disorders with chromosome 5 abnormalities: do de novo and therapy-related myelodysplastic syndrome-acute myeloid leukemia actually differ?

A retrospective cytogenetic study of acute myeloid leukemias (AML) and myelodysplastic syndromes (MDS) was conducted by the Groupe Francophone de Cytogénétique Hématologique (GFCH) to evaluate the structural abnormalities of chromosome 5 associated with other chromosomal abnormalities, in particular of chromosome 7, in these pathologies. In all, 110 cases of AML/MDS were recruited based on the presence of chromosome 5 abnormalities under conventional cytogenetics and supplemented by a systematic fluorescence in situ hybridization study of chromosomes 5 and 7. The abnormalities of the long arm of chromosome 5 (5q) were deletions of various sizes and sometimes cryptic. The 5q abnormalities were associated with translocations in 54% of cases and were simple deletions in 46%. In 68% of cases, 5q deletions were associated with chromosome 7 abnormalities, and 90% of these presented a complex karyotype. Of the 110 patients, 28 had a hematopoietic disorder secondary to chemotherapy, radiotherapy, or both. Among 82 patients with de novo AML/MDS, 63 were older than 60 years. Chromosomal abnormalities often associated hypodiploidy and chromosome 5 and 7 abnormalities in complex karyotypes, features resembling those of secondary hemopathies. Systematic investigation of the exposure to mutagens and oncogenes is thus essential to specify the factors potentially involved in MDS/AML with 5q abnormalities.

Advances in the management of low- to intermediate-risk myelodysplastic syndrome: Integrating the National Comprehensive Cancer Network guidelines

Myelodysplastic syndromes (MDSs) are a group of hematologic diseases that present unique challenges for oncology nurses, especially because patients with the disorders are being seen more often in oncology practices. An increasing array of therapeutic options are available, and the National Comprehensive Cancer Network published its first clinical practice guidelines for MDSs in 2004. This article provides oncology nurses with the most recent data on supportive care as well as emerging therapies for patients with low- to intermediate-risk MDS.

Etiology of acute myeloid leukemia in the elderly

The biologic and epidemiologic study of acute myeloid leukaemia (AML) in the elderly is in its infancy. Most epidemiologic data attempting to ascertain the etiology of AML have been obtained from younger cohorts or patients with therapy-related AML. The increasing prevalence of deletional and complex karyotypes in elderly AML patients implies a cumulative genotoxicity over time for this subgroup, given the similar spectrum of abnormalities following exposure to known genotoxic agents such as alkylating chemotherapeutic drugs. Exposure to benzene, radiation, and tobacco smoke are clear but weak risk factors for AML. Polymorphic variants in several genes responsible for genomic protection and integrity are now also weak risk factors for AML. Future epidemiologic studies should correlate exposure data with well-defined biologic subtypes of AML.

A case-control study of myelodysplastic syndromes in Belgrade (Serbia Montenegro)

The objective of the study was to investigate factors related to the occurrence of myelodysplatic syndromes (MDS) in the population of Belgrade (Serbia Montenegro). The case-control study was conducted during the period 2000-2003. The study group consisted of 80 newly diagnosed MDS patients and 160 sex- and age-matched hospital controls with nonmalignant and noninfectious diseases. The disease categories in the control group were circulatory (51 patients, 32%), gastrointestinal (53 patients, 33%), and ophthalmological (56 patients, 35%) disorders. Conditional univariate and multivariate logistic regression analyses were applied. Multivariate analysis showed the following factors to be significantly related to MDS: exposure to chemicals (OR = 10.8, 95%CI 3.2-36.2, p = 0.0001), viral upper respiratory tract infections (twice a year or more, OR = 5.8, 95%CI 2.5-13.6, p = 0.0001), exposure to insecticides, pesticides and herbicides (OR = 5.2, 95%CI 1.8-15.1, p = 0.003), coffee (OR = 5.1, 95%CI 1.9-13.7, p = 0.001), and alcohol consumption (OR = 2.2, 95%CI 1.1-4.6, p = 0.033). The findings support the hypotheses that exposure to chemical agents, pesticides, insecticides, and herbicides, certain lifestyle factors (alcohol and coffee consumption), and frequent viral infections may be involved in the etiology of MDS, but these results should be confirmed by further investigations.

Cytogenetic aspects of adult primary myelodysplastic syndromes: Clinical implications

Myelodysplastic syndrome (MDS) is a heterogeneous disease from the clinical, biological and morphological point of view. The pathogenesis of MDS is not well established and it appears to occur complex changes in the stem cell biology. Clonal chromosomal aberrations are found in 30-50% of primary MDS and no specific cytogenetic abnormality has as yet been defined. The chromosomal abnormalities are predominantly characterized by partial/total chromosomal losses or chromosomal gains. These chromosomal abnormalities include mainly -5/del(5q), -7/del(7q), del(11q), del(12p), del(20q), -Y, and +8. The role of cytogenetic analysis in the diagnosis, prognosis, taking treatment decisions and follow up of patients with MDS has been clearly defined. Despite its difficulties in obtaining for analysis high quality metaphases conventional cytogenetics continues to be the basic technique for cytogenetic evaluation of a MDS patient. Other molecular cytogenetic methods have been shown to be complementary, without replacing the information obtained with this technique. Further investigations with both conventional and molecular cytogenetics in relation to clinical features as well as other molecular methods will undoubtedly contribute to improve understanding of the underlying genetic events responsible for the development and evolution of MDS leading to more accurate classification and management of MDS patients.

Risk factors of myelodysplastic syndromes: a case-control study

Little is known about the etiology of myelodysplastic syndromes (MDS). A hospital-based case-control study of 354 adult de novo MDS cases and 452 controls was conducted to investigate associations between lifestyle characteristics and MDS risk. The distribution by French-American-British (FAB) type was 67 (19%) refractory anemia (RA), 38 (11%) refractory anemia with ringed sideroblasts (RARS), 43 (12%) chronic myelomonocytic leukemia (CMML), 136 (38%) RA with excess blasts (RAEB), and 70 (20%) RAEB in transformation (RAEBT). Multivariate logistic regression analyses were performed among all MDS cases and among each FAB type and gender. For all MDS combined, family history of hematopoietic cancer (odds ratio (OR) = 1.92), smoking (OR = 1.65), and exposure to agricultural chemicals (OR = 4.55) or solvents (OR = 2.05) were associated with MDS risk. Among RA/RARS cases, smoking (OR = 2.23) and agricultural chemical exposure (OR = 5.68) were the only risk factors identified. For RAEB/RAEBT cases, family history of hematopoietic cancer (OR = 2.10), smoking (OR = 1.52), and exposure to agricultural chemicals (OR = 3.79) or solvents (OR = 2.71) were independent risk factors. Drinking wine reduced risk for all FAB types by almost 50% (OR = 0.54). We found a joint effect between smoking and chemical exposure with the highest risk among smokers exposed to solvents/agricultural chemicals (OR = 3.22). Results from this large study suggest that several factors play a role in MDS predisposition with possible joint effects. Risk profiles seem to differ by FAB type and gender.