Review of NASA's Longitudinal Study of Astronaut Health (2004) / Chapter Skim
Currently Skimming:
3 Issues with Design and Implementation of the Current Longitudinal Study
3 Issues with Design and Implementation of the Current Longitudinal Study
Pages 29-38
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From page 29... ...
3. what are the long- term risks of working Ahovepopulations PLUS en ployees of in the en vironunff t of JSC?
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From page 30... ...
The first limes of Chapter I state that the purpose is to "examime the imcidence of acute and chronic morbidity an d mortality of astronauts and describe the risks of morbidity and mortality associated with the astmnautst occupational exposures, as compared with the risks for civil selvice employees of Johnson Space Center." It goes on to say that assessments of lifetime risk and flight-time risks for specific diseases and disorders 'will help to (1) identify health-related problems that require spacecraft medical facilities, and (2)
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From page 31... ...
A case could he made that LSAH data on thyroid fumction were useful m the decision to reduce the arnomlt of bactericidal iodine used m the shuttle's potable water, but as noted m the previous chapter, the LSAH seems to have played only a confumatory role m the discovery of iodine-induced thyroid dysfunction m shuttle astronauts. There is certainly no evidence t at the LSAH has ever been queried regularly enough and with suflicienLty powerful pattern detection methods to serve as the basis for am effective prevention program for current ard former astronauts.
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From page 32... ...
The table shows the minimum detectable relative risk (for astronauts relative to the comparison participants) for health conditions varying in prevalence in the comparison group from 0.1 percent to 10 percent.
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From page 33... ...
at Different Criteria for Statistical SigniEc~mce (two-tailed I) with Power = 0.80 Disease Prevalence an Comp UT on catsup Magnum Detectable Relative Risk n=0.05 n=0.10 n=0.15 0.1 percent 11.15 9.27 8.18 0.5 percent 3.89 3.44 3.17 1.0 percent 2.81 2.55 2.39 2.0percent 2.18 2.02 1.92 5.0 percent 1.70 1.61 1.55 10.0 percent 1.49 1.43 1.39 COMPOSITION OF THE COMPARISON GROUP The procedures used for selecting comparison particip~mts from among JSC civil servants have been successful im producing a cohort of individuals closely matched to the astronauts im gender, race, age, an d body mass index.
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From page 34... ...
Budgetary shortfalls over the years since the LSAH began have led to increasing disparities in the searches for health problems in the astronaut and comparison groups. The latter now receive physical exams half as frequently as the astronauts; some laboratory tests and physical evaluations that the astronauts receive yearly are provided to comparison participants only at four-year intervals; some procedures (Dual energy X-ray absorptiometry [DEXA]
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From page 35... ...
TABLE 3-3 Percentage of Active JSC Civil Servants, Ex-JSC Civil Servants, and Ex-Astronaut LSAH Participants Appearing for Scheduled Physical Exams, 1993-2001 1993 1994 1995 1996 1997 1998 1999 2000 2001 Active JSC 93 79 87 79 79 84 84 82 69 Fonner JSC Civil Servants Fommer Astronauts 72 53 61 67 59 65 59 63 50 71 69 61 64 61 88 63 74 68 Between 70 percent and 90 percent of active JSC civil servants receive their scheduled physical evaluations each year, but neither former JSC civil servants nor former astronauts regularly achieve a 70 percent return rate. Former astmnauts have been returning at a slightly higher rate tham former civil servants, at least in the 1998 to 2001 period.
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From page 36... ...
However, the committee is concerned that the content and format of the consent form provided to them is not up to currently acceptable standards, specifically on regard to varying statements about the goals of the study, possible benefits, risks to confidentiality, compensation for participating, and procedures for encouraging participation. The committee believes that the risks to both corfiidentiakty and full participation on the space program may not fall unto the manual risk category and encourages both the LSAH scientists and the NASA IRE to review the current mfornted consent process and make appropriate changes.
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From page 37... ...
When available LSAH data showed am association between cataract mcidence m astronauts (eye exarnmations for comparison participants is limited to visual acuity) and dose of radiation received during space flight radiation, the JSC scientific staff recogrized the limitations of the study amd contracted for a new study with more objective observation and classification of cataract severity amd a comparison/control group of Current and former military pilots age and gender matched to the astronauts.
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From page 38... ...
The proposal would exclude astronauts with thyroid autoantibodies or thyroid peroxidase antibodies from participating in long duration missions, including the Intemational Space Station, because of concern about increased risk of thyroid dysfunction or even clinical thyroid disease with extended exposure to even low levels of iodine during long duration flight. There are insufficient data in the LSAH at present to fully assess these risks, but elevated thyroid autoantibodies occur about three times more frequently in women than in men and increasing in age (Eheman, 2003)
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