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My Letter to Chest re: Ohar, et al article

Lawrence Martin, M.D., FCCP


9000 Mentor Avenue

Mentor, Ohio 44060

February 23, 2004

Letters to the Editor, Chest

3300 Dundee Road

Northbrook, IL 60062-2348

As a reviewer for Chest, I am surprised the article by Ohar et. al. (1) was published without closer analysis of the methods, and without editorial comment. There is a national epidemic of asbestos litigation (2), with most of the mass claims provably unfounded, and the mass claims process itself tainted by fraud and unethical behavior (3-8). Unfortunately, the article by Ohar et al can only harm attempts to bring objective diagnosis to these mass claims. Here are the article's problems.

1) All asbestos subjects came from 3383 people in the "Selikoff registry," people recruited from "trade unions, television and newspaper advertisements." In the Discussion section are we told that "subjects were recruited from legal cases based on the presence of a radiographic abnormality" and that this "could raise a question of potential selection bias." The authors discount this bias by claiming the controls had >= 10 years' observation without radiographic progression. Yet the controls were merely a subset (243) of the 3383 people solicited for the registry; this left 3140 people diagnosed -- because of some abnormality on chest x-ray -- with "asbestos-induced lung disease."

A subset of the original cohort is not a true control group. A true control group would be another 3000+ chest x-rays from a similar demographic group (age, sex and smoking history) without an asbestos exposure history. Chest x-rays of true controls would be mixed randomly along with the Selikoff registry chest x-rays, so that all 6000+ films could be read blindly. Furthermore, given interobserver variation among B-readers (9), an epidemiologic study based on x-rays should include at least three B-readers, each of whom must be blinded completely to the subjects' background.

2) The study omits possibility that some of the Selikoff registrants don't have asbestos-related disease. It is noteworthy that 74% of the asbestos subjects had an ILO score < 1/1, i.e., 1/0 or lower. There is now a substantial literature showing that a profusion reading of 1/0 is completely non-specific for diagnosis of interstitial lung disease, as it may be related to smoking history, aging, heart disease, and other non-fibrotic conditions (10-14). In fact, a recent article in Chest states: "the chest radiograph should not be used as the sole diagnostic tool as it will be wrong more often than it will be right." (14) It is inconceivable that not a single Selikoff registry subject had some other cause for small opacity profusion than asbestos.

3) The authors state that "pleural abnormalities were the only abnormality in 54% of subjects with low ILO scores." Yet it is well known that pleural abnormalities can be difficult to both diagnose on plain x-ray and attribute as to causation (15). For example, there are numerous causes of pleural shadows unrelated to asbestos, e.g., prior thoracic surgery, old inflammatory disease, healed rib fractures, obesity (pseudo pleural thickening), etc. (13, 15-16). It is inconceivable that not a single Selikoff registry subject had some other cause for pleural abnormality than asbestos.

4) Sixty-seven subjects (out of 3140 with "asbestos disease") had lung cancer, and only 1 of these was a never smoker. Yet all 67 cases of lung cancer were accepted by the authors as "asbestos-induced" (the article's title). There is considerable debate in the literature about the role of asbestos in causing lung cancer in the absence of true asbestosis (17-20), which for reasons already presented is not documented in this cohort.

A result of these errors is the unwarranted assumption that 92.7% of this cohort recruited for litigation purposes have asbestos-induced disease. This statistic flies in the face of clinical experience, and of anything published in the medical literature. It is even higher than the 60-80% positive diagnosis rate found when plaintiff attorneys pay for the B-reader reports! (8; page 86). In fact, objective review of asbestos diagnoses in these attorney-sponsored mass claims (of which the Selikoff registry is part) has shown mis-diagnosis in the vast majority of cases (8, 13, 21)

In epidemiologic studies like this one, unless all subjects are evaluated in a completely blinded fashion, the results can become self-fulfilling. As with B-readers who are paid for positive results by plaintiff's lawyers (5-8), the authors have assumed the diagnosis before it has been proven. The authors' basic conclusions -- that there is a changing pattern of asbestos-induced disease, and that "an augmented number of new cases of asbestos-induced lung disease may be anticipated in the next two decades" - are not only completely unfounded, but feed right into the plaintiff lawyers who developed the now discredited asbestos screening process. It seems no coincidence that this work, with its lack of true controls and unwarranted conclusions, was funded by the Selikoff registry.

Perhaps the authors are unaware of the Alice-in-Wonderland nature of mass asbestos litigation, or of the growing list of publications that has undermined its validity (2-16). Chest's review process should have been aware, caught the manifest conflict of interest as well as the illogical results, and at least published an editorial response.

The authors no doubt intended their study to be fair and valid, but intentions are not enough. The horrible quagmire of mass asbestos litigation mandates that epidemiologic studies on asbestos diagnosis be 100% blinded and include real controls (22), and that they in no way be funded by any source connected with plaintiff's attorneys. Without those protections against bias and illogic, the results can never be accepted as scientifically valid, no matter where they are published.

Lawrence Martin, M.D., FCCP

Associate Professor of Medicine

Case University School of Medicine

Phone: 440-974-4442

Fax: 440-964-4273



1. Ohar J, Sterling DA, Bleecker E, Donohue J. Changing patterns in asbestos-induced lung disease. Chest 2004;125:744-753.

2. Carroll S, Hensler D, Abrahamse A, Gross J, White M, Ashwood S, Sloss E. Asbestos Litigation Costs and Compensation: An Interim Report. RAND Corp, Santa Monica, CA, 2002.

3. Parloff R. The $200 billion miscarriage of justice. Fortune, March 4, 2002; 145:154-8.

4. Taylor S, Jr. Greedy lawyers cheat real asbestos victims. The Atlantic Online.

5. Egilman D. Asbestos screenings. Amer J Indust Med 2002;42:163.

6. Setter DM, Young KE, Kalish AL. Asbestos: Why we have to defend against screened cases. Mealey's Litigation Report, November 12, 2003;18:1-16.

7. Bernstein DB. Keeping junk science out of asbestos litigation. Pepperdine Law Review, Volume 31, No. 1, 2004; 11-28.

8. Brickman L: On the Theory Class's Theories of asbestos litigation: Disconnect between scholarship and reality. Pepperdine Law Review, Volume 31, No. 1, 2004; 33-170.

9. Ducatman AM, Yang WN, Forman SA. 'B-Readers' and asbestos medical surveillance. J Occup Med 1988; 30:644-647.

10. Weiss W. Cigarette smoking and small irregular opacities. Br J Indust Med 1991; 48:841-844.

11. Dick JA, Morgan WKC, Muir DFC, et al. The significance of irregular opacities on the chest roentgenogram. Chest 1992;102:251-260.

12. Meyer JD, Islam S, Ducatman AM, et al. Prevalence of small lung opacities in populations unexposed to dusts. A literature analysis. Chest 1997;111: 404-10.

13. Reger RB, Cole WS, Sargent EN, Wheeler PS. Cases of alleged asbestos-related disease: a radiologic re-evaluation. J Occup Med 1990; 32:1088-90.

14. Ross RM. The clinical diagnosis of asbestosis in this century requires more than a chest radiograph. Chest 2003;124:1120-28.

15. Lawson CC, LeMasters MK, LeMasters GK, et al. Reliability and validity of chest radiograph surveillance programs. Chest 2001;120:64-68.

16. Lee YC, Runnion CK, Pang SC, de Klerk NH, Musk AW. Increased body mass index is related to apparent circumscribed pleural thickening on plain chest radiographs. Am J Ind Med 2001 39:112-6.

17. Browne K. Is asbestos or asbestosis the cause of the increased risk of lung cancer in asbestos workers? Brit J Indust Med 1986;43:145-149.

18. Jones RN, Hughes JM, Weill H. Asbestos exposure, asbestosis, and asbestos-attributable lung cancer. Thorax 1996;51:S9-S14.

19. Weiss W. Asbestosis: A Marker for the Increased Risk of Lung Cancer Among Workers Exposed to Asbestos. Chest, February 1999;115(2):536-549.

20. Banks DE, et al. Asbestos Exposure, Asbestosis, and Lung Cancer (Editorial). Chest, February 1999; 115(2):320.

21. Houser PG: Affadavit in Manville Personal Injury Settlement Trust Medical Audit Procedures Litigation, 98 Civ. 5693, March 13, 1999, p. 9; quoted in Carroll S, Hensler D, Abrahamse A, Gross J, White M, Ashwood S, Sloss E. Asbestos Litigation Costs and Compensation: An Interim Report. RAND Corp, Santa Monica, CA, 2002.; page 20.

22. Martin L. Runaway Asbestos Litigation -- Why it's a Medical Problem

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