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RE: Cancer deficiency clusters



Reduced cancer risk in US Shipyard workers



John and colleagues,



Notwithstanding the abstract written by G. Matanoski, anyone can

calculate the odds ratio for all cancers in the nuclear shipyard

workers, compared to their non-nuclear counterparts.  Look at the

numbers in tables 3.6.A to 3.6.D (pages 359 to 366 of the June 1991 DOE

Report).



There are 848 cancer cases in 38220 nuclear workers and 878 cases in

32510 non-nuclear workers.  The odds ratio for cancer death in nuclear

workers is 0.8175 (95% Confidence Interval: 0.7430 to 0.8995, using the

approximation of Woolf), with a two-sided p value <0.0001, that is, near

certainty.  The Odds Ratio was calculated with INSTAT(R) (GraphPad

Software Inc., 5755 Oberlin Dr. # 110, San Diego CA 92121).  Anyone can

check the calculation from the numbers given in the report.  Odds ratios

are easy to calculate but correct confidence intervals are more

difficult to obtain without specialized software.  



Similarly, the histograms of age at entry and age distribution in

nuclear and non-nuclear workers, built form Tables 3.1.A1 and 3.1.A2 of

the report, show that the two populations are quite comparable.  The

reduced risk of cancer risk cannot be attributed to a healthy worker

effect in that study.  Similar calculations can be done for specific

cancers and any other cause of death examined by the authors.



Since anyone can replicate the above calculations, this should put an

end to speculations and to unfounded affirmations on what the DOE report

really contains.   



Reference



Matanoski G: Health effects of low-level radiation in shipyard workers

final report.  Baltimore, MD, DOE DE-AC02-79 EV10095, (1991) 



Philippe Duport



-----Original Message-----

From: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu] On Behalf Of Jacobus, John

(OD/ORS)

Sent: July 19, 2002 9:43 AM

To: 'RadSafe'

Subject: RE: Cancer deficiency clusters



Howard,

But if we question the validity of statistical cluster that show a

higher

increase of cancer near a power plant, it should be, and is,

statistically

probable that studies will show a statistical cluster of healthful

effects

of radiation.



You noted the Nuclear Shipyard Worker Study.  It you like, I will send a

copy of the abstract written by one of the authors of the study, Dr.

Genevieve Matanoski.  It appeared in Radiation Research 133, 126-127

(1993).

(I think it is important to supply references rather than speculations,

don't you?)  Quoting the abstract:



"The data clearly indicate that both nuclear worker groups have a lower

mortality from leukemia and lymphatic and hematopoietic cancers than

does

the nonnuclear group.  All three groups have lower rates than the

general

population.  However, if the NW<5.0 or the 5.0-9.0 mSv group is used for

comparison, than all dose groups 10 mSv and above in the NW>/= 5.0 group

have higher mortality rates that the NW<5.0 group for both leukemia and

all

lymphatic hematopoietic neoplasms.  There is no consistent dose response

with radiation, which would suggest that radiation is not the factor

associated with the increase. . . . The SMRs are very sensitive to any

changes, such as lagging, due to small numbers, so these within-group

observations may simply represent chance variations."



A couple of simplistic observations, since I am not an epidemiologist

but

feel that I can understand the basics.  First, this is a cohort study,

which

may not have any relevance to public exposures.  I guess that if you

want to

reduce your risk of cancer, you should work in Naval shipyard, since

"All

three groups have lower rates than the general population."  Second, the

risk mortality increases at occupational exposures above 10 mSv.

Third,

other factors that were not considered, such as asbestos exposures, may

influence the results as they may be more important than the factor,

radiation, that is being studied.  For example, the study indicates that

the

mortality from lung cancer for all groups was higher than that of the

general population.  But only the non-nuclear workers had a

statistically

significant increase.  I guess you can conclude that radiation reduces

the

risk of lung cancer in this cohort.  Of course, I would rather a more

qualified epidemiologist than I review the data.  While I admire John

Cameron for his work, he is not an epidemiologist either.



-- John 

John Jacobus, MS

Certified Health Physicist 

3050 Traymore Lane

Bowie, MD  20715-2024



E-mail:  jenday1@email.msn.com (H)      



-----Original Message-----

From: hflong@postoffice.pacbell.net

[mailto:hflong@postoffice.pacbell.net]

Sent: Friday, July 19, 2002 7:03 AM

To: jjcohen

Cc: Gibbs, S Julian; Jacobus, John (OD/ORS); Radsafe Mail list

Subject: Re: Cancer deficiency clusters





Yes, Jerry,

Such a study has been done on 27,872 nuclear shipyard workers - but

until

recently only reported as not showing expected increase in cancer.



John Cameron, one of 8 members of the technical advisory committee of

the

Nuclear Shipyard Workers Study reports, "The cancer death rate of the

NW>0.5

group [those receiving an extra 0.5 rem] was over 4 std.dev. lower than

the

NNW control group [non-nuclear workers of similar ages and jobs]. This

good

news is not mentioned but the data are available in the final report."

http://www.aps.org/units/fps/oct01/a5oct01.html

. . .

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