Abstract
BACKGROUND: In case-control studies, data collection on occupational exposures by means of personal interviews is usually costly and time consuming. As detailed semiquantitative information on exposure from these interviews often has to be dichotomised in the analyses due to the small numbers of exposed subjects, the question is raised whether simple postal questionnaires yield the same results for occupational exposure in epidemiological studies as job specific personal interviews. METHODS: Data on occupational exposures during pregnancy were compared from 121 women who both completed a checklist with 17 occupational exposure categories in a postal questionnaire and were personally interviewed with specific questions on exposure with details of job and task. kappa Coefficients were calculated as measures of agreement corrected for chance, and sensitivity and positive predictive values as measures of validity and usefulness, with the exposure assessment based on information from the interview as the gold standard. RESULTS: Values of kappa varied from 0.09 for domestic cleaning agents to 0.70 for pesticides, indicating only low to moderate agreement between the questionnaire and the interview. Sensitivity ranged from 38% to 100%, with the highest values for agents used by healthcare workers. Positive predictive values were lower, between 9% and 63%, which indicates that overreporting was more common than underreporting in the questionnaire. CONCLUSIONS: These results underline the high potential for misclassification of occupational exposure in studies based on questionnaires. Therefore, postal questionnaires are not considered an alternative to job and task specific personal interviews in epidemiological studies.
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Selected References
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- Baumgarten M., Siemiatycki J., Gibbs G. W. Validity of work histories obtained by interview for epidemiologic purposes. Am J Epidemiol. 1983 Oct;118(4):583–591. doi: 10.1093/oxfordjournals.aje.a113663. [DOI] [PubMed] [Google Scholar]
- Blatter B. M., Roeleveld N., Zielhuis G. A., Gabreëls F. J., Verbeek A. L. Maternal occupational exposure during pregnancy and the risk of spina bifida. Occup Environ Med. 1996 Feb;53(2):80–86. doi: 10.1136/oem.53.2.80. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Blatter B. M., Roeleveld N., Zielhuis G. A., Mullaart R. A., Gabreëls F. J. Spina bifida and parental occupation. Epidemiology. 1996 Mar;7(2):188–193. doi: 10.1097/00001648-199603000-00014. [DOI] [PubMed] [Google Scholar]
- Eskenazi B., Pearson K. Validation of a self-administered questionnaire for assessing occupational and environmental exposures of pregnant women. Am J Epidemiol. 1988 Nov;128(5):1117–1129. doi: 10.1093/oxfordjournals.aje.a115054. [DOI] [PubMed] [Google Scholar]
- Goldberg M., Hémon D. Occupational epidemiology and assessment of exposure. Int J Epidemiol. 1993;22 (Suppl 2):S5–S9. doi: 10.1093/ije/22.supplement_2.s5. [DOI] [PubMed] [Google Scholar]
- Gérin M., Siemiatycki J., Kemper H., Bégin D. Obtaining occupational exposure histories in epidemiologic case-control studies. J Occup Med. 1985 Jun;27(6):420–426. [PubMed] [Google Scholar]
- Hemminki K., Lindbohm M. L., Kyyrönen P. Validity aspects of exposure and outcome data in reproductive studies. J Occup Environ Med. 1995 Aug;37(8):903–907. doi: 10.1097/00043764-199508000-00003. [DOI] [PubMed] [Google Scholar]
- Joffe M. Validity of exposure data derived from a structured questionnaire. Am J Epidemiol. 1992 Mar 1;135(5):564–570. doi: 10.1093/oxfordjournals.aje.a116323. [DOI] [PubMed] [Google Scholar]
- Lantz C. A., Nebenzahl E. Behavior and interpretation of the kappa statistic: resolution of the two paradoxes. J Clin Epidemiol. 1996 Apr;49(4):431–434. doi: 10.1016/0895-4356(95)00571-4. [DOI] [PubMed] [Google Scholar]
- Rona R. J., Mosbech J. Validity and repeatability of self-reported occupational and industrial history from patients in EEC countries. Int J Epidemiol. 1989 Sep;18(3):674–679. doi: 10.1093/ije/18.3.674. [DOI] [PubMed] [Google Scholar]
- Stewart P. A., Stewart W. F. Occupational case-control studies: II. Recommendations for exposure assessment. Am J Ind Med. 1994 Sep;26(3):313–326. doi: 10.1002/ajim.4700260305. [DOI] [PubMed] [Google Scholar]
- Stewart W. F., Stewart P. A. Occupational case-control studies: I. Collecting information on work histories and work-related exposures. Am J Ind Med. 1994 Sep;26(3):297–312. doi: 10.1002/ajim.4700260304. [DOI] [PubMed] [Google Scholar]
- Teschke K., Kennedy S. M., Olshan A. F. Effect of different questionnaire formats on reporting of occupational exposures. Am J Ind Med. 1994 Sep;26(3):327–337. doi: 10.1002/ajim.4700260306. [DOI] [PubMed] [Google Scholar]
