Biomedical subjects

M Linet

Publications and source records attributed to M Linet.

At least 19 recordsLinked to original sources

PubMed2002

Myeloma aetiology and epidemiology.

Recently there have been substantial improvements in our understanding of the biology of myeloma. These findings have important implications for aetiological studies aimed at defining the causative factors for myeloma. Myeloma is closely related to monoclonal gammopathy of unknown significance (MGUS), which is now recognized to be very common in the older population. The epidemiology of these conditions is presented and discussed in the context of the genetic factors governing both the risk of developing MGUS or of transformation to myeloma. Biological studies support a role for aberrant class switch recombination early in the natural history of myeloma suggesting that factors in the environment may interact with this mechanism to increase myeloma risk. Case-control and cohort studies have identified several known and suspected environmental exposures. These exposures include high doses of ionizing radiation, and occupational exposure in the farming and petrochemical industries. The data supporting these associations are presented and discussed in the context of the molecular mechanisms underlying these exposures. In particular DNA damage occurring as a consequence could readily interact with the class switch recombination process to increase the risk of chromosomal translocations, oncogene deregulation and malignant transformation. A further hypothesis, which has been extensively investigated, is the role of chronic immune/antigenic stimulation and the risk of myeloma. This concept is difficult to explain in the context of our current immunological concepts. The data supporting the association and how molecular epidemiological studies using genetic variants in cytokine genes are allowing us to revisit this concept are discussed in detail.

Animals↗

PubMed2001

Benzene and lymphohematopoietic malignancies in humans.

BACKGROUND: Quantitative evaluations of benzene-associated risk for cancer have relied primarily on findings from a cohort study of highly exposed U.S. rubber workers. An epidemiologic investigation in China (NCI/CAPM study) extended quantitative evaluations of cancer risk to a broader range of benzene exposures, particularly at lower levels. METHODS: We review the evidence implicating benzene in the etiology of hematopoietic disorders, clarify methodologic aspects of the NCI/CAPM study, and examine the study in the context of the broader literature on health effects associated with occupational benzene exposure. RESULTS: Quantitative relationships for cancer risk from China and the U.S. show a relatively smooth increase in risk for acute myeloid leukemia and related conditions over a broad dose range of benzene exposure (below 200 ppm-years mostly from the China study and above 200 ppm-years mostly from the U.S. study). CONCLUSIONS: Risks of acute myeloid leukemia and other malignant and nonmalignant hematopoietic disorders associated with benzene exposure in China are consistent with other information about benzene exposure, hematotoxicity, and cancer risk, extending evidence for hematopoietic cancer risks to levels substantially lower than had previously been established. Published 2001 Wiley-Liss, Inc.

Benzene↗

PubMed2001

Review of the epidemiologic literature on EMF and Health.

Exposures to extremely low-frequency electric and magnetic fields (EMF) emanating from the generation, transmission, and use of electricity are a ubiquitous part of modern life. Concern about potential adverse health effects was initially brought to prominence by an epidemiologic report two decades ago from Denver on childhood cancer. We reviewed the now voluminous epidemiologic literature on EMF and risks of chronic disease and conclude the following: a) The quality of epidemiologic studies on this topic has improved over time and several of the recent studies on childhood leukemia and on cancer associated with occupational exposure are close to the limit of what can realistically be achieved in terms of size of study and methodological rigor. b) Exposure assessment is a particular difficulty of EMF epidemiology, in several respects: i) The exposure is imperceptible, ubiquitous, has multiple sources, and can vary greatly over time and short distances. ii) The exposure period of relevance is before the date at which measurements can realistically be obtained and of unknown duration and induction period. iii) The appropriate exposure metric is not known and there are no biological data from which to impute it. c) In the absence of experimental evidence and given the methodological uncertainties in the epidemiologic literature, there is no chronic disease for which an etiological relation to EMF can be regarded as established. d) There has been a large body of high quality data for childhood cancer, and also for adult leukemia and brain tumor in relation to occupational exposure. Among all the outcomes evaluated in epidemiologic studies of EMF, childhood leukemia in relation to postnatal exposures above 0.4 microT is the one for which there is most evidence of an association. The relative risk has been estimated at 2.0 (95% confidence limit: 1.27-3.13) in a large pooled analysis. This is unlikely to be due to chance but, may be, in part, due to bias. This is difficult to interpret in the absence of a known mechanism or reproducible experimental support. In the large pooled analysis only 0.8% of all children were exposed above 0.4 microT. Further studies need to be designed to test specific hypotheses such as aspects of selection bias or exposure. On the basis of epidemiologic findings, evidence shows an association of amyotrophic lateral sclerosis with occupational EMF exposure although confounding is a potential explanation. Breast cancer, cardiovascular disease, and suicide and depression remain unresolved.

Adolescent↗

PubMed2000

Mortality among radiologic technologists in the united states (1926-1997). 2(nd) Follow up.

PURPOSE: To evaluate risk for all-cause and cause-specific mortality in a large, primarily female (73%) cohort of radiologic technologists.METHODS: The study consists of 145,915 radiation technologists, certified in the American Registry of Radiologic Technologists (1926-1982) and followed through 1997. Causes of death were obtained from death certificates or, more recently, through NDI Plus. Standardized Mortality Ratios (SMR) were computed and tests of homogeneity were performed to detect differences in mortality among causes. Poisson models were used to estimate risks using an internal comparison group.RESULTS: Significantly low SMRs were observed for all causes (0.76), all cancers (0.82), and diseases of circulatory system (0.69). Compared to U.S. women, the risk for breast cancer mortality bordered around unity (SMR 1.01, 95% CI 0.94-1.09). However, relative to all other cancers, breast cancer mortality was significantly increased (RSMR 1.24, p < 0.01). Elevated risk for breast cancer was associated with certification before 1940 (SMR 1.55, 95% CI 1.24-1.91), and duration of certification of 20-29 (SMR 1.21, 95% CI 1.06-1.37) and 30+ years (SMR 1.77, 95% CI 1.54-2.02). A 35% increase in leukemia risk was evident for women certified for a duration of 20-29 years and a 36% increase among women certified for 30+ years. Poisson analysis revealed a significant increase in breast cancer risk with increasing number of years certified among women first certified before 1940 (p < 0.001) and during 1940-49 (p = 0.05) compared to women first certified in 1950 or later.CONCLUSIONS: Preliminary findings of this study suggest increased breast cancer risk associated with occupational radiation exposures prior to 1950 and with long-term cumulative exposures. However, potential confounding by reproductive and other risk factors needs to be evaluated.

Journal Article↗

PubMed2000

Trends in reproductive, smoking, and other chronic disease risk factors by birth cohort in a large occupational study.

PURPOSE: To illustrate the value of using large cohort studies to identify birth cohort trends in several chronic disease risk factors.METHODS: In collaboration with the American Registry of Radiologic Technologists (ARRT) and the University of Minnesota, the National Cancer Institute (NCI) initiated a cohort study of radiologic technologists who were certified by ARRT for at least two years between 1926 and 1982. Over 90,000 technologists (nearly four-fifths female) from all 50 states responded to a mailed questionnaire on reproductive, medical, work, and lifestyle factors. Ten, mostly five-year, birth cohorts, from before 1920 through 1960 and later, were evaluated.RESULTS: In this population, the mean height of both men and women generally rose in each subsequent birth cohort. The proportion of men who smoked before age 18 fell among those born since the late 1920s. In contrast, the proportion of women smoking before age 18 rose among those born since the early 1950s, reaching 14.2% among those born in 1960 and later. The mean age at menarche fell, until leveling off at 12.5, among those born after 1940. Recent birth cohorts (since 1950) show among the highest mean ages at birth of first child (>26 yeras), highest rates of nulliparity at age 25 (>/=63%), and lowest mean parity levels (</=1.7), compared with earlier birth cohorts. The proportion of women ever using oral contraceptives rose steadily by birth cohort, reaching 86 percent in the most recent birth cohort.CONCLUSIONS: Some of the trends observed may help explain historic chronic disease incidence patterns and predict future disease burdens.

Journal Article↗

PubMed2000

A pooled analysis of magnetic fields and childhood leukaemia.

Previous studies have suggested an association between exposure to 50-60 Hz magnetic fields (EMF) and childhood leukaemia. We conducted a pooled analysis based on individual records from nine studies, including the most recent ones. Studies with 24/48-hour magnetic field measurements or calculated magnetic fields were included. We specified which data analyses we planned to do and how to do them before we commenced the work. The use of individual records allowed us to use the same exposure definitions, and the large numbers of subjects enabled more precise estimation of risks at high exposure levels. For the 3203 children with leukaemia and 10 338 control children with estimated residential magnetic field exposures levels < 0.4 microT, we observed risk estimates near the no effect level, while for the 44 children with leukaemia and 62 control children with estimated residential magnetic field exposures >/= 0.4 microT the estimated summary relative risk was 2.00 (1.27-3.13), P value = 0.002). Adjustment for potential confounding variables did not appreciably change the results. For North American subjects whose residences were in the highest wire code category, the estimated summary relative risk was 1.24 (0.82-1.87). Thus, we found no evidence in the combined data for the existence of the so-called wire-code paradox. In summary, the 99.2% of children residing in homes with exposure levels < 0.4 microT had estimates compatible with no increased risk, while the 0.8% of children with exposures >/= 0.4 microT had a relative risk estimate of approximately 2, which is unlikely to be due to random variability. The explanation for the elevated risk is unknown, but selection bias may have accounted for some of the increase.

Adolescent↗

PubMed1999

Sunlight and non-Hodgkin's lymphoma: a population-based cohort study in Sweden.

Indirect evidence, notably ecological comparisons and an association with skin cancer, links non-Hodgkin's lymphoma (NHL) with exposure to sunlight. We conducted a population-based, nationwide cohort study with exposure to outdoor work inferred from job titles reported in the population and housing censuses in 1960 and/or 1970 and by classifying each individual's work and home addresses according to latitude. Follow-up for cancer incidence was accomplished through record linkages with the virtually complete Swedish Cancer Registry. The cohort included all Swedish residents who were recorded as gainfully employed in both censuses. Altogether 4,171,175 individuals contributing 69,639,237 person-years accrued through 1989 were included in the analyses. We identified 10,381 cases of NHL, 4,018 cases of chronic lymphocytic leukemia (CLL), 11,398 cases of malignant melanoma (MM) and 11,913 cases of squamous cell skin cancer (SCC). We calculated age-adjusted relative risks for NHL, CLL, MM and SCC in strata based on estimated residential and occupational sunlight exposure. Interaction effects were considered for pesticide and solvent exposure. NHL, MM and SCC, but not CLL, were positively associated with increasingly southerly residential latitude, with stronger associations seen for skin cancer compared to NHL. Occupational sun exposure was not associated with the risk of developing any of the studied cancers. Pesticides and solvents also were not related to an increased risk of NHL, nor did these exposures enhance effects of residential or occupational sunlight exposure. Our results provide some support for an association of sunlight exposure with NHL incidence based on the associations seen using geographic latitude of residence as a proxy for exposure. Although type of occupation may be an imperfect index of the biologically relevant ultraviolet (UV) light dose, our data on individual exposure are not consistent with an important role of sunlight in the etiology of NHL.

Age Factors↗

PubMed1999

Investigation of leukemia cells from children with common acute lymphoblastic leukemia for genomic sequences of the primate polyomaviruses JC virus, BK virus, and simian virus 40.

BACKGROUND: An infectious etiology for childhood acute lymphoblastic leukemia (ALL) has long been suspected, although the characteristics of the putative childhood ALL-inducing agent(s) remain a mystery. We describe the testing of ALL leukemia cells for the presence of DNA sequences of the polyomavirus family: JC virus, BK virus, and simian virus 40 (SV40). PROCEDURE: Cryopreserved leukemia cells from 25 children between 2 and 5 years of age at the time of diagnosis and classified as having "common" ALL (B-precursor ALL expressing the CD19 and CD10 surface antigens) were tested for the presence of polyomavirus sequences using standard PCR methods. RESULTS: Human beta-globin gene sequences were detected in 22 of 25 leukemia specimens. However, polyomavirus sequences were not detected in any of the 22 specimens with amplifiable DNA. CONCLUSIONS: The inability to detect JC virus, BK virus, and SV40 virus DNA sequences in any of the 22 specimens with amplifiable DNA suggests that that these members of the polyomavirus family are unlikely to be causally associated with most childhood ALL. Published 1999 Wiley-Liss, Inc.

BK Virus↗

PubMed1998

Risk for endometrial cancer in relation to occupational physical activity: a nationwide cohort study in Sweden.

Notwithstanding its biologic plausibility, the association between physical activity and endometrial cancer has been analyzed in only a few epidemiological studies. Retrospective assessment of exposure and small sample size often hampers interpretation of published data. We studied risk for endometrial cancer in relation to physical activity at work in a large cohort of Swedish women identified in the nationwide censuses in 1960 and 1970, with jobs that could be consistently classified into one of 4 levels of physical demands. Follow-up from 1971 through 1989 was accomplished through record linkages. Multivariate Poisson regression models were used to estimate relative risk. The risk for endometrial cancer increased regularly with decreasing level of occupational physical activity (p for trend < 0.001), and was associated more strongly with activity in 1970 than in 1960. In multivariate analyses, adjusted for age at follow-up, place of residence, calendar year of follow-up, and social class, the relative risk among women with the same physical activity level in 1960 and in 1970 was 30% higher for sedentary as compared with high/very high activity level; (p for trend=0.04). The protective effect of physical activity appeared to be confined to women aged 50 to 69, among whom sedentary work was associated with a 60% higher risk than that observed among women estimated to be physically most active. The excess seemed to disappear within 10 years after a change in physical activity level. Although confounding cannot be ruled out in our data, occupational physical activity appears to reduce the risk for endometrial cancer.

Adult↗

PubMed1998

Venous thromboembolism and cancer.

BACKGROUND: Although cancer has been clearly associated with venous thromboembolism (VTE), many aspects of this relation are poorly understood, including the cancer sites most affected and the cancer risk during long-term follow-up. To clarify these relations, we carried out a large, population-based analysis of VTE and cancer risk. METHODS: Using the Swedish Inpatient Register and linkage to the nationwide Cancer Registry, we assessed cancer incidence during 1989 among 61,998 patients without a previous cancer diagnosis admitted to hospital between 1965 and 1983 for VTE. To measure possible increases in cancer risk, we computed standardised incidence ratios (SIRs) using Swedish national cancer rates for the period of the study. FINDINGS: At the time of thromboembolic admission or during the first year of follow-up, 2509 cancers were diagnosed (SIR 4.4, 95% CI 4.2-4.6) [corrected]. The SIR for polycythaemia vera was 12.9 (8.6-18.7), and the SIRs for cancers of the liver, pancreas, ovary, and brain, and for Hodgkin lymphoma also exceeded 5.0. Patients aged less than 65 years had higher SIRs than those who were older. In subsequent years, 6081 cancers were diagnosed (1.3, 1.3-1.3). Even 10 years or more after admission to hospital with VTE, cancer incidence had increased (1.3, 1.3-1.4). INTERPRETATION: At the time of VTE or in the first year afterwards, we found a large increase in the risk for diagnosis of virtually all cancers. In subsequent years, a persistent 30% increase in risk remains. Either premalignant change promotes thrombosis, or cancer and thrombosis share common risk factors.

Cohort Studies↗

PubMed1998

Risk of liver and other types of cancer in patients with cirrhosis: a nationwide cohort study in Denmark.

Cancer risk in patients with cirrhosis could be modified by factors such as changes in hormonal levels, impaired metabolism of carcinogens, or alteration of immunological status. We investigated the risk of liver and various forms of cancer in patients with cirrhosis in a follow-up study. We identified 11,605 1-year survivors of cirrhosis from the files of the Danish National Registry of Patients (NRP) from 1977 to 1989. Occurrence of cancer through 1993 was determined by linkage to the Danish Cancer Registry. For comparison, the expected number of cancer cases was estimated from national age-, sex-, and site-specific incidence rates. Overall, 1,447 cancers were diagnosed among the study subjects, as compared with 708.1 expected, to yield a standardized incidence ratio (SIR) of 2.0 (95% CI: 1.9 to 2.2). In all diagnostic subgroups of cirrhosis, the risk of primary liver cancer, mainly hepatocellular carcinoma, was markedly elevated, with 245 observed cases and an overall 36-fold elevated risk (59.9-fold elevated for hepatocellular carcinoma and 10-fold for cholangiocarcinoma). Substantial and persistent excesses during follow-up were seen for all types of cancer associated with tobacco and alcohol habits (cancer of the lung, larynx, buccal cavity, pharynx, pancreas, urinary bladder, and kidney), while moderate excesses were seen for cancers of the colon and breast. The latter, however, were not complemented by any decrease in the risk of prostate cancer (SIR: 1.0; 95% CI: 0.7 to 1. 3). A slightly increased risk was seen for testis cancer, but disappeared after 10 years. We found evidence of an increased risk for liver and several extrahepatic cancers in patients with cirrhosis. Although part of this increase is likely attributable to alcohol and tobacco consumption, our study opens up the possibility that cirrhosis plays a role in the carcinogenesis of types of cancer other than liver cancer.

Adult↗

PubMed1998

Risk of breast cancer in men with liver cirrhosis.

OBJECTIVE: Liver cirrhosis is associated with increased levels of estrogens, which may be causally related to breast cancer. Because background estrogen levels are lower in men than in women, an estrogen-mediated link between liver cirrhosis and breast cancer would be easier to detect in men. METHODS: Men hospitalized with liver cirrhosis in Denmark from January 1, 1977, to December 31, 1989, were followed up, through record linkage, until the end of December 1993 for the possible occurrence of breast cancer. RESULTS: A total of 11,642 men with liver cirrhosis were identified and were followed for a mean period of 4.3 yr, for a total of 49,687 person-years. Three cases of male breast cancer were observed whereas 0.75 was expected, for a standardized incidence ratio of 4.0 (95% confidence interval, 0.8-11.7). CONCLUSIONS: Cirrhosis, possibly via high levels of endogenous estrogens, increases the risk of breast cancer in men.

Breast Neoplasms, Male↗

PubMed1997

Validation of benzene exposure assessment.

We conducted a methodologic study to validate a quantitative retrospective exposure assessment method used in a follow-up study of workers exposed to benzene. Assessment of exposure to benzene was carried out in 672 factories in 12 cities in China. Historical exposure data were collected for 3179 unique job titles. The basic unit for exposure assessment was a factory/work-unit/job-title combination over seven periods between 1949 and 1987. A total of 18,435 exposure estimates was developed, using all available historical information, including 8477 monitoring data. Overall, 38% of the estimates were based on benzene monitoring data. The highest time-weighted average exposures occurred in the rubber industry (30.7 ppm), particularly for rubber glue applicators (52.6 ppm). Because of its recognized link with benzene exposure, the association between a clinical diagnosis of benzene poisoning (hematotoxicity) and benzene exposure was evaluated (412 cases and 614,509 person-years) to validate the exposure-assessment method. Relative risks of benzene hematotoxicity increased very sharply with increasing estimated intensity of benzene exposure. Odds ratios were 2.2 (95% CI: 1.7-2.9), 4.7 (95% CI: 3.4-6.5), and 7.2 (95% CI: 5.3-9.8) for the intensity levels of less than 5 ppm, 5-19 ppm, 20-39 ppm, and 40 and more ppm, respectively. This sharp trend between benzene hematotoxicity and estimated exposure to benzene indicated that the exposure-estimation method used in this cancer epidemiology study is reliable.

Benzene↗

PubMed1997

Cancer incidence in a population-based cohort of patients hospitalized with diabetes mellitus in Denmark.

BACKGROUND: Diabetes has been associated with an increased risk of several cancers, notably cancers of the pancreas, liver, endometrium, and kidney. Since most previous studies have involved a limited sample size or focused on specific cancer sites, we conducted a comprehensive assessment of the risk of cancer in a nationwide cohort of diabetics in Denmark. METHODS: Discharge records of 109581 individuals hospitalized with a diagnosis of diabetes from 1977 through 1989 were linked with national cancer registry records through 1993. Standardized incidence ratios (SIRs) were calculated for specific cancer sites. RESULTS: The SIRs for primary liver cancer were 4.0 (95% confidence interval [CI] = 3.5-4.6) in males and 2.1 (95% CI = 1.6-2.7) in females. These SIRs remained elevated with increasing years of follow-up and after exclusion of patients with reported risk factors (e.g., cirrhosis and hepatitis) or patients whose cancers were diagnosed at autopsy. Kidney cancer risk was also elevated, with SIRs of 1.4 (95% CI = 1.2-1.6) in males and 1.7 (95% CI = 1.4-1.9) in females. For both sexes combined, the SIR for pancreatic cancer was 2.1 (95% CI = 1.9-2.4), with a follow-up time of 1-4 years; this SIR declined to 1.3 (95% CI = 1.1-1.6) after 5-9 years of follow-up. Excess risks were also observed for biliary tract and endometrial cancers. The SIRs for kidney and endometrial cancers declined somewhat after exclusion of diabetics with reported obesity. CONCLUSIONS: Patients hospitalized with a diagnosis of diabetes appear to be at higher risk of developing cancers of the liver, biliary tract, pancreas, endometrium, and kidney. The elevated risks of endometrial and kidney cancers, however, may be confounded by obesity.

Age Distribution↗

PubMed1997

Benzene poisoning, a risk factor for hematological malignancy, is associated with the NQO1 609C-->T mutation and rapid fractional excretion of chlorzoxazone.

Benzene is a ubiquitous occupational hematotoxin and leukemogen, but people vary in their response to this toxic agent. To evaluate the impact of interindividual variation in enzymes that activate (i.e., CYP2E1) and detoxify (i.e., NQO1) benzene and its metabolites, we carried out a case-control study in Shanghai, China, of occupational benzene poisoning (BP; i.e., hematotoxicity), which we show is itself strongly associated with subsequent development of acute nonlymphocytic leukemia and the related myelodysplastic syndromes (relative risk, 70.6; 95% confidence interval, 11.4-439.3). CYP2E1 and NQO1 genotypes were determined by PCR-RFLP, and CYP2E1 enzymatic activity was estimated by the fractional excretion of chlorzoxazone (fe(6-OH)) for 50 cases of BP and 50 controls. Subjects with both a rapid fe(6-OH). and two copies of the NQO1 609C-->T mutation had a 7.6-fold (95% confidence interval, 1.8-31.2) increased risk of BP compared to subjects with a slow fe(6-OH) who carried one or two wild-type NQO1 alleles. In contrast, the CYP2E1 PstI/RsaI polymorphism did not influence BP risk. This is the first report that provides evidence of human susceptibility to benzene-related disease. Further evaluation of susceptibility for hematotoxicity and hematological malignancy among workers with a history of occupational exposure to benzene is warranted.

Benzene↗

PubMed1996

Maternal and perinatal factors associated with non-Hodgkin's lymphoma among children.

This nested case-control study based on 1.7 million live births in Sweden explores the associations between maternal and perinatal factors and the occurrence of childhood non-Hodgkin's lymphoma (NHL). The National Swedish Cancer Registry ascertained 168 cases in successive birth cohorts from 1973 through 1989 recorded in the Swedish Medical Birth Registry. From the nationwide Birth Registry, 5 controls without NHL and alive at the date the case was diagnosed were randomly selected from the pool of children, with each case matched by gender, birth year and birth month. Standardized information on selected maternal and perinatal factors up to one month after delivery were recorded in the Medical Birth Registry. Mothers of children with NHL were more likely than mothers of controls to have undergone Cesarean section [Odds ratio (OR) 1.6] and to have been exposed to paracervical anesthesia during delivery (OR 1.8). Children with NHL were more likely than controls to have endocrine-metabolic disorders (OR 3.3). This study is one of the largest focusing on the etiology of childhood NHL. Most of the maternal and perinatal characteristics studied did not markedly affect risk for childhood NHL, which may be due to maternal and perinatal factors not included in these data or to exposures later in life.

Adolescent↗

PubMed1996

Hematotoxicity among Chinese workers heavily exposed to benzene.

Benzene is a well-established hematotoxin. However, reports of its effects on specific blood cells have been somewhat inconsistent and the relative toxicity of benzene metabolites on peripheral blood cells in humans has not been evaluated. We compared hematologic outcomes in a cross-sectional study of 44 workers heavily exposed to benzene (median: 31 parts permillion [ppm] as an 8-hr time-weighted average [TWA] and 44 age and gender-matched unexposed controls from Shanghai, China. All hematologic parameters (total white blood cells [WBC], absolute lymphocyte count, platelets, red blood cells, and hematocrit) were decreased among exposed workers compared to controls, with the exception of the red blood cell mean corpuscular volume (MCV), which was higher among exposed subjects. In a subgroup of workers who were not exposed to more than 31 ppm benzene on any of 5 sampling days (n = 11, median 8 hr TWA = 7.6 ppm, range = 1-20 ppm), only the absolute lymphocyte count was significantly different between exposed workers (mean [sd]1.6 [0.4] x 10(3) mu L) and controls (1.9 [0.4] x l0(3) uL, p = 0.03). Among exposed subjects, a dose response relationship with various measures of current benzene exposure (i.e., personal air monitoring, benzene metabolites in urine) was present only for the total WBC count, the absolute lymphocyte count, and the MCV. Correlations between benzene metabolites and hematologic parameters were generally similar, although hydroquinone was somewhat more strongly associated with a decrease in the absolute lymphocyte count, and catechol was more strongly associated with an increase in MCV. Morphologic review of peripheral blood slides demonstrated an excess of red blood cell abnormalities (i.e., stomatocytes and target cells) only in the most heavily exposed workers, with no differences in granulocyte, lymphocyte, or platelet morphology noted. Although benzene can affect all the major peripheral blood elements, our results support the use of the absolute lymphocyte count as the most sensitive indicator of benzene-induced hematotoxicity.

Adult↗

PubMed1996

A novel approach to data collection in a case-control study of cancer and occupational exposures.

BACKGROUND: In community and hospital-based case-control studies, the occupational data collected in interviews are usually limited to responses to general questions asked of all study subjects. A procedure is described in which more detailed information can be collected in an efficient, standardized and systematic way. METHODS: A generic work history is initially collected from all subjects using a computer-assisted interview. The work history includes job title, type of business, job activities, materials and chemicals, and tools and equipment used. After responses are entered into the computer by the interviewer, the computer searches a synonym file to identify possible job-specific modules relevant to the reported job. The modules are detailed questionnaires that address specific jobs administered after obtaining the generic work history. The modules are used to ask questions about the work environment; sources of exposure; factors affecting the movement of the agent from the source to the subject, such as local exhaust ventilation; and individual and job characteristics. After the interview is completed, the work history and responses to the modules are sent electronically to an industrial hygienist who reviews the information using a custom-designed software package. Where ambiguities or contradictions occur in information reported by the respondent, or for jobs for which no module had been developed, the industrial hygienist generates up to 10 additional questions per job. These questions are sent back to the interviewer for administration of a short, second interview. CONCLUSIONS: These procedures, which are being successfully implemented in an on-going case-control study of brain tumours, should improve disease risk estimates over those derived from more traditional approaches to exposure assessment.

Brain Neoplasms↗