High-risk mesothelioma relation to meteorological and geological condition and distance from naturally occurring asbestos

Our plain-English summary of High-risk mesothelioma relation to meteorological and geological condition and distance from naturally occurring asbestos, by A. Abakay, A.C. Tanrikulu, M. Ayhan, et al (Environmental Health and Preventive Medicine, 2016).

The study

• Authors: A. Abakay, A.C. Tanrikulu, M. Ayhan, M.S. Imamoglu, M. Taylan, M.A. Kaplan, O. Abakay
• Journal: Environmental Health and Preventive Medicine
• Published: 2016;21(2):82-90
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: Very few studies have investigated the incidence and risk of malignant mesothelioma (MM) associated with distinct sources of asbestos exposure, especially exposure to naturally occurring asbestos (NOA).

Methods: Subjects were MM, lung, and breast cancer patients who were diagnosed and followed in Diyarbakir Province between 2008 and 2013. The birthplaces of patients were displayed on a geologic map. Geological and meteorological effects on MM were analyzed by logistic regression.

Results: A total of 180 MM, 368 breast, and 406 lung cancer patients were included. The median distance from birthplace to ophiolites was 6.26 km for MM, 31.06 km for lung, and 34.31 km for breast cancer (p < 0.001). The majority of MM cases were seen within 20 km from NOA areas. The MM incidence inside of NOA was 1059/100.000, and out of NOA was 397/100.000; this difference was significant (p = 0.014). The largest concentration of MM residential areas was within ± 30° (34 residential areas 36.6%) of the dominant wind direction. Most MM patients were found in or near the dominant wind direction, especially in the acute angle defined by the dominant wind direction. MM incidence was directly proportional to {[area of NOA (km(2))] * [cosine α of wind direction angle]} and was inversely proportional to the square of the distance (R = 0.291, p = 0.023).

Conclusions: MM was higher near NOA and in the downwind direction. MM incidence and risk were affected by geological and meteorological factors.

In plain English

This retrospective study mapped the birthplaces of 180 malignant mesothelioma (MM), 368 breast cancer and 406 lung cancer patients in Diyarbakir Province, Turkey, against ophiolite rock areas containing naturally occurring asbestos (NOA). Patients were followed at Dicle University Hospital from 2008 to 2013, and MM patients with occupational exposure were excluded. The summary birthplace distances from these areas were 6.26 km for MM, 31.06 km for lung cancer and 34.31 km for breast cancer patients. The article calls these medians in some places and means in others. Of 180 MM cases, 150 were born within 20 km of NOA. Averaged across the 37 residential areas of MM patients inside NOA, MM incidence was 1059 per 100,000. Averaged across the 56 areas outside, it was 397 per 100,000, a significant difference (p = 0.014). The largest group of MM residential areas, 34 of 93 (36.6%), lay within 30 degrees of the dominant wind. A regression model linked MM incidence to NOA area, wind angle and distance (R = 0.291, p = 0.023). The authors concluded that geological and meteorological factors affect MM incidence and risk. They noted using only birthplace, not full residential or job histories.

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: Retrospective study comparing the birthplaces of mesothelioma patients with those of lung and breast cancer patients, plus an area-level analysis of mesothelioma incidence by residential area
• Who was studied: 180 patients with histologically proven malignant mesothelioma, from 93 residential areas, plus 368 breast cancer patients and 406 lung cancer patients. All were born in Diyarbakir Province, Turkey, and followed at Dicle University Hospital from January 2008 to December 2013.
• Exposure: Environmental exposure to naturally occurring asbestos in ophiolite rock areas. It was measured by four factors: birthplace distance from these areas, position relative to the dominant (northwest) wind direction, NOA area size, and rock type (Guleman ophiolite, Kocali complex, Karadut complex). Patients with occupational, domestic or para-occupational exposure were excluded. No fiber measurements were made in this study.
• Main results:
  • The group summary birthplace distances from ophiolites were 6.26 km for MM patients, 31.06 km for lung cancer patients and 34.31 km for breast cancer patients. MM patients were significantly closer than either comparison group. The article labels these figures as medians in some places and means in others.
  • Lung cancer patients were born closer to NOA than breast cancer patients, but this difference was not statistically significant.
  • Of the 180 MM cases, 150 were born within 20 km of NOA areas.
  • Mean MM incidence was 1059/100,000 across the 37 residential areas (settlements of MM patients' birthplaces) inside asbestos source areas. It was 397/100,000 across the 56 residential areas outside them (p = 0.014).
  • Mean MM incidence was highest in residential areas located at the asbestos source and lowest in those more than 10 km away.
  • MM incidence was significantly higher in or near Guleman ophiolite (JKg) and Kocali complex (JKk) rocks than in or near Karadut complex (Kk) rocks.
  • The largest number of MM residential areas, 34 (36.6%), lay within plus or minus 30 degrees of the dominant wind direction.
  • In a regression model, MM incidence rose with NOA area multiplied by the cosine of the wind-direction angle. It fell with the square of the distance from the source (R = 0.291, p = 0.023).
• The authors' conclusion: The authors concluded that MM was higher in areas near NOA and aligned with the dominant wind direction. They also concluded that MM incidence and risk are affected by geological and meteorological factors.
• Limitations the authors state:
  • The duration of cumulative fiber exposure could not be estimated, because only place of birth was considered and not full residential or occupational histories.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, naturally occurring asbestos (NOA), Malignant Mesothelioma, Asbestos Exposure, Lung Cancer, Ophiolite.

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