Systematic Review of the Effects of Asbestos Exposure on the Risk of Cancer between Children and Adults

Our plain-English summary of Systematic Review of the Effects of Asbestos Exposure on the Risk of Cancer between Children and Adults, by D. Kang, M.S. Myung, Y.K. Kim, et al (Annals of Occupational and Environmental Medicine, 2013).

The study

• Authors: D. Kang, M.S. Myung, Y.K. Kim, J.E. Kim
• Journal: Annals of Occupational and Environmental Medicine
• Published: 2013;25(1):10
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Children are considerably more susceptible to enviro006Emental hazards than adults. This study was conducted to investigate whether the first asbestos exposure in childhood increases the risk of asbestos-related cancer including mesothelioma and lung cancer. MEDLINE (PubMed), Embase, and Google Scholar were searched to find relevant studies published up to July 2012. Six studies reported the relationship between age, including age during childhood, at the first asbestos exposure and mesothelioma. Among them, 4 indicated that people exposed to asbestos in childhood have a higher risk of mesothelioma than those exposed in adulthood. Meanwhile, the other 2 studies showed that asbestos exposure later in life increases the risk of mesothelioma. The results of the 2 studies including non-occupational early childhood exposure report conflicting results. There were 3 studies regarding the relationship between age at first asbestos exposure and lung cancer. However, none of them reported an association between age at first asbestos exposure and the risk of lung cancer. All studies have limitations including small numbers of subjects, the validity of the standardized mortality ratio, and different age categories at first asbestos exposure. There are only a few studies on the harmful effects of asbestos in children in the literature. Therefore, the effect of asbestos exposure during childhood remains unclear and requires further study.

In plain English

This was a systematic review of published studies on whether first exposure to asbestos in childhood changes the risk of asbestos-related cancer compared with first exposure in adulthood. The authors searched MEDLINE (PubMed), Embase and Google Scholar for studies published up to July 2012. The search returned 10,877 articles, and 6 studies were included, from Hong Kong, France, the UK, Italy, Australia and New Caledonia. The authors had planned a meta-analysis but could not combine the studies because they used different age groups and different risk measures. For mesothelioma, 4 studies (Lacourt, Rake, Pira and Luce) reported higher risk with younger age at first exposure. The other 2 (Chen and Reid) reported higher risk with older age at first exposure. In Reid's study of residents of Wittenoom, Western Australia, people first exposed at 15 or older had a hazard ratio of 3.88 (95% CI 2.2-6.8) compared with those first exposed under 15. The 3 studies that examined lung cancer showed no association with age at first exposure. The authors concluded that the effect of childhood exposure remains unclear and needs further study.

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: Systematic review of published studies. A meta-analysis was planned but not done because the studies used different age categories and outcome measures.
• Who was studied: Studies in MEDLINE (PubMed), Embase and Google Scholar published up to July 2012. Of 10,877 articles found, 6 studies were included: Chen (Hong Kong), Lacourt (France), Rake (UK), Pira (Italy), Reid (Australia) and Luce (New Caledonia).
• Exposure: Age at first asbestos exposure, compared across childhood and adult age categories. Four studies dealt with occupational exposure, Rake with domestic exposure, and Reid and Luce with residential (environmental) exposure.
• Main results:
  • For mesothelioma, 4 of the 6 studies (Lacourt, Rake, Pira, Luce) indicated higher risk with childhood or younger first exposure. The other 2 (Chen, Reid) indicated higher risk with exposure later in life.
  • Lacourt (occupational, France): the odds ratio for mesothelioma was 12.3 (95% CI 9.0-16.9) for first exposure at age 15 and 1.8 (95% CI 1.1-3.0) at age 30. These figures are for 40 years of total exposure duration.
  • Rake (occupational and domestic, UK): the odds ratio for mesothelioma was 9.2 (95% CI 6.4-13.1) for first exposure under 20 years and 1.7 (95% CI 0.7-3.9) for first exposure at 30 years or more.
  • Reid (residential, Wittenoom, Western Australia): compared with people first exposed under 15 years (hazard ratio 1.00), those first exposed at 15 years or more had a hazard ratio of 3.88 (95% CI 2.2-6.8). The mesothelioma rate in those first exposed under 15 was about 25% of the rate in those first exposed older, after adjusting for exposure and sex.
  • Chen (occupational, Hong Kong): the mesothelioma standardized mortality ratio was 5,556.19 (95% CI 2,872.6-9,723.3) for workers starting before age 20 and 7,494.63 (95% CI 2,428.3-17,462.5) for those starting at 20 or older.
  • Lung cancer: the 3 studies that examined it (Chen, Pira, Luce) showed no association between age at first asbestos exposure and lung cancer risk.
• The authors' conclusion: The authors concluded that, because there were few studies and they were of limited quality, no clear conclusion could be drawn. In their view, the effect of childhood asbestos exposure remains unclear and requires further study.
• Limitations the authors state:
  • The authors could not be certain that all relevant studies were found by their search.
  • The included studies used varying age categories, mainly splitting at around 20 years, so a single childhood category does not capture differences within childhood.
  • Two studies relied on standardized mortality ratios, which the authors consider a less preferable risk measure, usually used when there are few deaths.
  • The lung cancer studies had small study populations, and none excluded other possible risk factors in their statistical analyses.
  • Because most childhood exposure comes from the environment, the precise age at first exposure is difficult to determine.

Topics

Medical terms in this study, explained in our Lexicon: Systematic Review, Asbestos Exposure, Mesothelioma, Lung Cancer, standardized mortality ratio (SMR).

Related studies

• Are children more vulnerable to mesothelioma than adults? A comparison of mesothelioma risk among children and adults exposed non-occupationally to blue asbestos at Wittenoom — A. Reid, P. Franklin, et al. (2018)
• Response to: 'Are children more vulnerable to mesothelioma than adults? A comparison of mesothelioma risk among children and adults exposed non-occupationally to blue asbestos at Wittenoom' by Reid et al — A. Farioli, P. Boffetta, et al. (2019)
• Cytoreductive surgery and Hyperthermic Intraperitoneal Chemotherapy (HIPEC) for children, adolescents, and young adults: the first 50 cases — A. Hayes-Jordan, H. Green, et al. (2015)
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• Family history of cancer and risk of paediatric and young adult's testicular cancer: A Norwegian cohort study — R. Del Risco Kollerud, E. Ruud, et al. (2019)
• Identification of adults at high risk of lung cancer — A.B. Miller (1980)

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