Can the birth certificate yield clues to parental occupational exposures?

Our plain-English summary of Can the birth certificate yield clues to parental occupational exposures?, by S. Milham (American Journal of Industrial Medicine, 1989).

The study

• Author: S. Milham
• Journal: American Journal of Industrial Medicine
• Published: 1989;16(2):235-7
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000131).

Abstract

An analysis of reported birth record variables by parental occupation suggests that certain birth outcomes may identify toxic or carcinogenic occupational exposures of the parents. Fathers coded to an asbestos and insulation worker rubric sired fewer plural births, and more stillbirths than expected. A number of other fathers' occupations with putative exposure to asbestos and increased lung cancer mortality also showed a deficit of plural births.

In plain English

This short report asked whether birth certificates might point to harmful workplace exposures in parents. The author analyzed all 1980-1986 Washington State birth and fetal death records (495,904 births, including 3,374 fetal deaths). Outcomes such as plural births (twins or more), stillbirths, malformations and birthweight were compared across parents' recorded occupations. Among 760 births to fathers coded as asbestos and insulation workers, there were 6 plural births where 16.1 were expected, and 11 stillbirths where 4.0 were expected. Both differences were statistically significant. Other fathers' occupations with significantly fewer plural births than expected included boilermakers, carpenters, roofers and sheetmetal workers, which the author described as having asbestos exposure. The list also included aluminum workers, gardeners and landscapers, and restaurant workers or owners. The author cautioned that with thousands of comparisons, many results would be significant by chance alone, and that it is hard to explain how a father's exposure could affect multiple births. The author concluded that the findings, if substantiated, suggest a new and quick way to identify potential occupational carcinogens.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Analysis of state birth and fetal death records (occupational natality surveillance), cross-tabulating birth outcomes by recorded parental occupation, with chi-square tests
• Who was studied: All Washington State births and fetal deaths, 1980-1986: 495,904 births including 3,374 fetal deaths. Fathers' occupation was given for 403,020 births and missing for 92,884 (19%).
• Exposure: Parental occupation as coded on the birth certificate. No fiber types or doses were measured. The author described asbestos and insulation workers, boilermakers, roofers, sheetmetal workers and carpenters as having asbestos exposure.
• Main results:
  • Births to fathers coded as asbestos and insulation workers had 6 plural births among 760 births, where 16.1 were expected (p less than 0.05). That is 7.9 per 1000, compared with 21.2 per 1000 for all occupations.
  • Births to fathers coded as asbestos and insulation workers had 11 stillbirths among 760 births, where 4.0 were expected based on all births with a stated fathers' occupation (statistically significant excess).
  • Other fathers' occupations with significantly low plural births (observed vs expected) were: boilermaker 2 vs 8.3 (393 births); carpenter 178 vs 232.8 (11,085 births); roofer 20 vs 33.2 (1,581 births); sheetmetal worker 20 vs 37.2 (1,770 births); aluminum worker 27 vs 41.8 (1,992 births); restaurant worker or owner 64 vs 82.4 (3,922 births); gardener/landscaper 37 vs 53.8 (2,562 births).
• The authors' conclusion: The author concluded that the findings, if substantiated, suggest a new and quick method of identifying potential occupational carcinogens, with the advantage of a short latency period.
• Limitations the authors state:
  • Because thousands of cross-tabulations were done, many results would reach statistical significance by chance alone. The author argued the occupations found are unlikely to be a random sample.
  • The author noted it is much more difficult to understand how a father's exposure could affect multiple birth frequency than a mother's.

Topics

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Carcinogenic, Insulator, Lung Cancer.

Related studies

• A task-based assessment of parental occupational exposure to organic solvents and other compounds and the risk of childhood leukemia in California — C. Metayer, G. Scelo, et al. (2016)
• Parental occupational exposure and risk of childhood central nervous system tumors: a pooled analysis of case-control studies from Germany, France, and the UK — C. Huoi, A. Olsson, et al. (2014)
• Death certificates in epidemiological studies, including occupational hazards: inaccuracies in occupational categories — I.J. Selikoff (1992)
• Modeled exposure to tetrachloroethylene-contaminated drinking water and the occurrence of birth defects: a case-control study from Massachusetts and Rhode Island — A. Aschengrau, L.G. Gallagher, et al. (2018)
• Use of job-exposure matrix in an occupational analysis of lung and bladder cancers on the basis of death certificates — D. Coggon, B. Pannett, et al. (1984)
• Use of death certificates in epidemiological studies, including occupational hazards: variations in discordance of different asbestos-associated diseases on best evidence ascertainment — I.J. Selikoff, H. Seidman (1992)

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