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A meta-analysis of occupational trichloroethylene exposure and selected cancers
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ABSTRACTS (ACE)
an important role in nucleotide excision repair (NER) and longpatch base-excision repair (BER). The A / C polymorphism in exon 6 might affect the transcription and/or translation and consequently influence the DNA repair capacity. The objectives of this study were to evaluate the associations between the polymorphisms of LIG1 and the head and neck cancers risk, and to investigate the potential interactions between the polymorphisms and the environmental factors. METHODS: This study was a population-based case-control study with 601 head and neck cancer cases and 1040 population controls in Los Angeles County. Epidemiological data were collected by face-to-face interviews using a standard questionnaire. Laboratory analysis on the genetic polymorphisms of LIG1 was performed with PCR-RFLP. Unconditional logistic regression model was employed in data analysis. RESULTS: The results showed an OR Z 1.1 (95% CI 0.8 – 1.5) for AA vs. AC and CC, adjusting for age, sex, alcohol drinking and tobacco smoking. In addition, the joint effect analysis showed an adjusted OR of 7.5 (95% CI 3.0 – 18.3) for those who drank more than 25 alcohol/day)years, smoked more than 40 pack-years and were with AA LIG1 genotype (versus less than 25 alcohol/ day)years, less than 40 pack-years and with AC/CC LIG1 genotype). CONCLUSION: The analysis suggested there was weak evidence of the association between LIG1 polymorphisms and head and neck cancers risk. Nonetheless, the results implied a strong modifying effect of both the alcohol and tobacco combined for the effect of LIG1 polymorphisms on the risk of head and neck cancers.
P07 ASSESSING ACTIVITIES ASSOCIATED WITH TIME SPENT OUTDOORS IN AN OCCUPATIONAL COHORT OF RADIOLOGIC TECHNOLOGISTS RK Kwok1, T Fears2, RA Kleinerman2, DM Freedman2, BH Alexander3, D Kampa3, RE Johnson1, MS Linet2, 1 RTI International, Research Triangle Park, NC, 2Division of Cancer Epidemiology and Genetics, Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD, 3Division of Environmental Health Sciences, University of Minnesota, Minneapolis, MN PURPOSE: To identify key daily activities in which persons working as radiologic technologists spend the majority of time outdoors. The findings will be used to design improved questionnaires to estimate retrospective UV exposure for future casecontrol studies of skin cancer and other malignancies to be undertaken within a large cohort of these medical radiation workers. METHODS: We evaluated the self-reported activities undertaken during time spent outdoors between 9 AM and 5 PM for 125 individuals (ages 40–59 and 60+ years old) who filled out a 7–day daily activity diary in September 2004. Daily UV measurements were also recorded for each individual. We initially classified activities into 37 groupings of similar activities before determining the 7 activities that accounted for the majority of time spent outdoors. We evaluated differences by age, gender, and geographic location of the individual in addition to whether these activities were carried out on a weekday or weekend day.
AEP Vol. 15, No. 8 September 2005: 630–665
RESULTS: Of a possible 13,953 daily diary entries, we ascertained that 4697 entries (totaling 1408 hours) were associated with time spent outdoors. The 7 major categories, which accounted for over 93% of the total time spent outdoors, included driving, yard work, home maintenance, walking or doing errands, recreational activities or sports, water activities, and leisure activities or relaxing outside. Differences in time spent outdoors were noted for age, gender, and weekend versus weekday. CONCLUSION: The results of this analysis, in conjunction with UV measurements, will be useful in developing questionnaires that more accurately estimate UV exposure in relation to cancer risks in future case-control studies.
P08 A META-ANALYSIS OF OCCUPATIONAL TRICHLOROETHYLENE EXPOSURE AND SELECTED CANCERS MA Kelsh1, M Weingart1, JH Mandel1, PJ Mink1, DD Alexander1, R Basu1, M Goodman2, 1Exponent, Inc., Menlo Park, CA, Oakland, CA; Chicago, IL; Washington, DC, 2Rollins School of Public Health, Emory University, Atlanta, GA PURPOSE: This review and meta-analysis evaluated occupational studies of TCE exposure and leukemia, non-Hodgkin’s lymphoma (NHL), and cancers of the lung, kidney, liver, and esophagus. METHODS: We summarized findings among occupational cohort studies and case-control studies that attempted to specifically identify and characterize TCE exposure. We identified 25 epidemiologic studies that met our inclusion criteria (17 cohort studies, 8 case-control studies). Cohort studies were categorized into ‘‘Group 1’’ and ‘‘Group 2’’ studies by type of exposure information available. RESULTS: The meta-analysis relative risk estimates (mRR) for kidney cancer suggested homogeneity of findings across studies in the Group 1 category (p value Z 0.97) with similar findings among U.S., European, and Aerospace/Aircraft studies. For liver cancer, mRR estimates varied. Aerospace/aircraft workers and Group 2 studies showed no association, whereas across European studies the mRR was slightly elevated. The findings for NHL indicated significant heterogeneity with lower mRRs among United States and aerospace/aircraft worker studies compared to a higher mRR for the European studies. Findings for esophageal cancer across studies were also heterogeneous. Similar to liver cancer and NHL, a pattern of higher mRRs was noted among European studies compared to other subgroups. CONCLUSION: This meta-analysis of occupational TCE exposure and NHL, leukemia, and cancers of the kidney, liver, esophagus, and lung showed no associations with lung and leukemia and inconsistent associations for kidney, liver, NHL and esophageal cancers across the Group 1 cohort studies considered as more informative. Heterogeneity of findings, limitations in exposure assessment and exposure comparability, and differences in disease classification limit interpretation of the epidemiologic data.
ABSTRACTS (ACE)
an important role in nucleotide excision repair (NER) and longpatch base-excision repair (BER). The A / C polymorphism in exon 6 might affect the transcription and/or translation and consequently influence the DNA repair capacity. The objectives of this study were to evaluate the associations between the polymorphisms of LIG1 and the head and neck cancers risk, and to investigate the potential interactions between the polymorphisms and the environmental factors. METHODS: This study was a population-based case-control study with 601 head and neck cancer cases and 1040 population controls in Los Angeles County. Epidemiological data were collected by face-to-face interviews using a standard questionnaire. Laboratory analysis on the genetic polymorphisms of LIG1 was performed with PCR-RFLP. Unconditional logistic regression model was employed in data analysis. RESULTS: The results showed an OR Z 1.1 (95% CI 0.8 – 1.5) for AA vs. AC and CC, adjusting for age, sex, alcohol drinking and tobacco smoking. In addition, the joint effect analysis showed an adjusted OR of 7.5 (95% CI 3.0 – 18.3) for those who drank more than 25 alcohol/day)years, smoked more than 40 pack-years and were with AA LIG1 genotype (versus less than 25 alcohol/ day)years, less than 40 pack-years and with AC/CC LIG1 genotype). CONCLUSION: The analysis suggested there was weak evidence of the association between LIG1 polymorphisms and head and neck cancers risk. Nonetheless, the results implied a strong modifying effect of both the alcohol and tobacco combined for the effect of LIG1 polymorphisms on the risk of head and neck cancers.
P07 ASSESSING ACTIVITIES ASSOCIATED WITH TIME SPENT OUTDOORS IN AN OCCUPATIONAL COHORT OF RADIOLOGIC TECHNOLOGISTS RK Kwok1, T Fears2, RA Kleinerman2, DM Freedman2, BH Alexander3, D Kampa3, RE Johnson1, MS Linet2, 1 RTI International, Research Triangle Park, NC, 2Division of Cancer Epidemiology and Genetics, Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD, 3Division of Environmental Health Sciences, University of Minnesota, Minneapolis, MN PURPOSE: To identify key daily activities in which persons working as radiologic technologists spend the majority of time outdoors. The findings will be used to design improved questionnaires to estimate retrospective UV exposure for future casecontrol studies of skin cancer and other malignancies to be undertaken within a large cohort of these medical radiation workers. METHODS: We evaluated the self-reported activities undertaken during time spent outdoors between 9 AM and 5 PM for 125 individuals (ages 40–59 and 60+ years old) who filled out a 7–day daily activity diary in September 2004. Daily UV measurements were also recorded for each individual. We initially classified activities into 37 groupings of similar activities before determining the 7 activities that accounted for the majority of time spent outdoors. We evaluated differences by age, gender, and geographic location of the individual in addition to whether these activities were carried out on a weekday or weekend day.
AEP Vol. 15, No. 8 September 2005: 630–665
RESULTS: Of a possible 13,953 daily diary entries, we ascertained that 4697 entries (totaling 1408 hours) were associated with time spent outdoors. The 7 major categories, which accounted for over 93% of the total time spent outdoors, included driving, yard work, home maintenance, walking or doing errands, recreational activities or sports, water activities, and leisure activities or relaxing outside. Differences in time spent outdoors were noted for age, gender, and weekend versus weekday. CONCLUSION: The results of this analysis, in conjunction with UV measurements, will be useful in developing questionnaires that more accurately estimate UV exposure in relation to cancer risks in future case-control studies.
P08 A META-ANALYSIS OF OCCUPATIONAL TRICHLOROETHYLENE EXPOSURE AND SELECTED CANCERS MA Kelsh1, M Weingart1, JH Mandel1, PJ Mink1, DD Alexander1, R Basu1, M Goodman2, 1Exponent, Inc., Menlo Park, CA, Oakland, CA; Chicago, IL; Washington, DC, 2Rollins School of Public Health, Emory University, Atlanta, GA PURPOSE: This review and meta-analysis evaluated occupational studies of TCE exposure and leukemia, non-Hodgkin’s lymphoma (NHL), and cancers of the lung, kidney, liver, and esophagus. METHODS: We summarized findings among occupational cohort studies and case-control studies that attempted to specifically identify and characterize TCE exposure. We identified 25 epidemiologic studies that met our inclusion criteria (17 cohort studies, 8 case-control studies). Cohort studies were categorized into ‘‘Group 1’’ and ‘‘Group 2’’ studies by type of exposure information available. RESULTS: The meta-analysis relative risk estimates (mRR) for kidney cancer suggested homogeneity of findings across studies in the Group 1 category (p value Z 0.97) with similar findings among U.S., European, and Aerospace/Aircraft studies. For liver cancer, mRR estimates varied. Aerospace/aircraft workers and Group 2 studies showed no association, whereas across European studies the mRR was slightly elevated. The findings for NHL indicated significant heterogeneity with lower mRRs among United States and aerospace/aircraft worker studies compared to a higher mRR for the European studies. Findings for esophageal cancer across studies were also heterogeneous. Similar to liver cancer and NHL, a pattern of higher mRRs was noted among European studies compared to other subgroups. CONCLUSION: This meta-analysis of occupational TCE exposure and NHL, leukemia, and cancers of the kidney, liver, esophagus, and lung showed no associations with lung and leukemia and inconsistent associations for kidney, liver, NHL and esophageal cancers across the Group 1 cohort studies considered as more informative. Heterogeneity of findings, limitations in exposure assessment and exposure comparability, and differences in disease classification limit interpretation of the epidemiologic data.