Residential radon and risk of lung cancer in Eastern Germany

Our plain-English summary of Residential radon and risk of lung cancer in Eastern Germany, by M. Kreuzer, J. Heinrich, G. Wölke, et al (Epidemiology, 2003).

The study

• Authors: M. Kreuzer, J. Heinrich, G. Wölke, A. Schaffrath Rosario, M. Gerken, J. Wellmann, G. Keller, L. Kreienbrock, H.E. Wichmann
• Journal: Epidemiology
• Published: 2003;14(5):559-68
• Cited by: 33 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: There is suggestive evidence that residential radon increases lung cancer risk. To elucidate this association further, we conducted a case-control study in Thuringia and Saxony in Eastern Germany during 1990-1997.

Methods: Histologically confirmed lung cancer patients from hospitals and a random sample of population controls matched on age, sex and geographical area were personally interviewed with respect to residential history, smoking, and other risk factors. One-year radon measurements were performed in houses occupied during the 5-35 years prior to the interview. The final analysis included a total of 1,192 cases and 1,640 controls. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by logistic regression.

Results: Measurements covered on average 72% of the exposure time window, with mean radon concentrations of 76 Bq/m3 among the cases and 74 Bq/m3 among the controls. The smoking- and asbestos-adjusted ORs for categories of radon (50-80, 80-140 and >140 Bq/m*3, compared with 0-50 Bq/m3) were 0.95 (CI = 0.77 to 1.18), 1.13 (CI = 0.86 to1.50) and 1.30 (CI = 0.88 to 1.93). The excess relative risk per 100 Bq/mł was 0.08 (CI = -0.03 to 0.20) for all subjects and 0.09 (CI = -0.06 to 0.27) for subjects with complete measurements for all 30 years.

Conclusions: Our data indicate a small increase in lung cancer risk as a result of residential radon that is consistent with the findings of previous indoor radon and miner studies.

In plain English

This case-control study in Thuringia and Saxony, Eastern Germany, examined whether radon in homes was linked to lung cancer. Its main exposure was radon; occupational asbestos exposure was asked about and treated as a potential confounder. Hospital lung cancer patients and population controls were interviewed in 1990–1997, and radon was measured for one year in homes occupied 5 to 35 years before the interview. The analysis included 1,192 cases and 1,640 controls. Average radon was 76 Bq/m3 among cases and 74 Bq/m3 among controls. Compared with 0–50 Bq/m3, odds ratios adjusted for smoking and asbestos were 0.95 (95% confidence interval 0.77 to 1.18) for 50–80 Bq/m3, 1.13 (0.86 to 1.50) for 80–140 Bq/m3 and 1.30 (0.88 to 1.93) for over 140 Bq/m3. The excess relative risk per 100 Bq/m3 was 0.08 (minus 0.03 to 0.20). Among men, 30% of cases and 28% of controls reported occupational asbestos exposure. The authors concluded that their data indicated a small increase in lung cancer risk with residential radon, most pronounced for small cell lung cancer. They noted that only 46% of controls took part.

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: Case-control study with lung cancer cases recruited from hospitals and population controls frequency-matched on sex, age and region, analysed with conditional logistic regression
• Who was studied: Lung cancer cases from the 5 hospitals in Thuringia and Saxony that treat lung cancer, and population controls, recruited 1990–1997. Former uranium-mining workers were excluded. 1,815 cases and 1,933 controls were interviewed. After excluding people with incomplete smoking histories or no valid radon measurement, the analysis included 1,192 cases (1,046 men, 146 women) and 1,640 controls (1,414 men, 226 women).
• Exposure: Residential radon, measured with alpha-track detectors placed for one year in the living room and bedroom of homes occupied 5 to 35 years before the interview, expressed as a time-weighted average concentration in Bq/m3. Smoking and occupational asbestos exposure were treated as the two main confounders. Subjects who reported a job with a potential lung cancer risk were asked in more detail about asbestos, and asbestos entered the models as exposed or not exposed.
• Main results:
  • The time-weighted average radon concentration over 5 to 35 years before interview was 76 Bq/m3 among cases and 74 Bq/m3 among controls.
  • All subjects, compared with 0–50 Bq/m3, odds ratios adjusted for smoking and asbestos: 0.95 (CI 0.77 to 1.18) for 50–80 Bq/m3, 1.13 (CI 0.86 to 1.50) for 80–140 Bq/m3, and 1.30 (CI 0.88 to 1.93) for over 140 Bq/m3.
  • All subjects: the adjusted excess relative risk was 0.08 (CI minus 0.03 to 0.20) per 100 Bq/m3 increase in radon.
  • Subjects with complete radon measurements for the whole 5 to 35 year period (427 cases and 536 controls): excess relative risk per 100 Bq/m3 of 0.09 (CI minus 0.06 to 0.27). The authors observed no major difference from the main analysis.
  • By cell type, the strongest evidence for a trend was for small cell lung cancer: excess relative risk 0.23 per 100 Bq/m3 (CI printed as 0.02 to 0.47).
  • Occupational asbestos exposure was reported by 30% of male cases and 28% of male controls. Only a negligible proportion of women were exposed to asbestos.
• The authors' conclusion: The authors concluded that their data indicated a small increase in lung cancer risk with increasing residential radon exposure. The increase was most pronounced for small cell lung cancer and similar in size to other residential radon studies and to extrapolations from miner studies.
• Limitations the authors state:
  • Cases were recruited through hospitals because there was no complete cancer registry. Estimated coverage was about 50% of cases in the study area, so how representative the cases are cannot be measured directly.
  • Only 46% of controls responded, and selection bias could not be ruled out.
  • 33% of interviewed cases and 14% of controls were excluded because radon measurements were missing.
  • Radon exposure outside the home (outdoors or at work) was not taken into account.
  • Radon exposure assessment may have been inaccurate.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Lung Cancer, Case-Control Study, Odds Ratio, confidence interval, Relative Risk.

Related studies

• Increased lung cancer risk due to residential radon in a pooled and extended analysis of studies in Germany — H.E. Wichmann, A.S. Rosario, et al. (2005)
• Case-control study on lung cancer and residential radon in western Germany — L. Kreienbrock, M. Kreuzer, et al. (2001)
• Residential radon exposure and lung cancer--an epidemiological study of Norwegian municipalities — K. Magnus, A. Engeland, et al. (1994)
• Indoor radon levels in urban Hyderabad area, Andhra Pradesh, India — M. Sreenath Reddy, P. Yadagiri Reddy, et al. (2008)
• Occupational risk factors for lung cancer in women: results of a case-control study in Germany — I. Jahn, W. Ahrens, et al. (1999)
• Risk factors for lung cancer in Iowa women: implications for prevention — J.S. Neuberger, J.D. Mahnken, et al. (2006)

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