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Review of NASA's Longitudinal Study of Astronaut Health (2004)

Chapter:4 Recommendations for Changes in Study Design and Execution

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Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
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4
Recommendations for Changes in Study Design and Execution

The scientific and medical staff of the National Aeronautics and Space Administration (NASA) and the Wyle Laboratories contractors assisting them in managing the Longitudinal Study of Astronaut Health (LSAH) are well aware of the issues in study design and execution outlined in the previous chapter. In her presentation to the Institute of Medicine (IOM) committee in January 2003, Mary Wear in fact included their suggestions for correcting many of those deficiencies (Wear, 2003). This chapter will enumerate those suggestions and the committee’s analysis of them, and then turn to additional recommendations from the committee itself.

LSAH STAFF RECOMMENDATIONS FOR CHANGE

LSAH scientists put forth suggested improvements to the study in three areas during their discussions with the IOM committee in March 2003: (1) improving the percentage of comparison participants returning to the Occupational Health Clinic at the Johnson Space Center (JSC) for physical exams, (2) improving the quality of the data collected from the comparison participants to provide a closer match to the data of the astronaut group, and (3) querying the database more frequently and systematically.

Improving the Quality of the Data Collected from the Comparison Participants

Budgetary restrictions have thus far prevented implementation, but LSAH staff members have proposed the following changes to the study:

Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
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  • Offer the same physical examinations to the comparison participants as offered to the astronauts, on the same schedule.

  • Include dual energy X-ray absorptiometry (DEXA) scans for the comparisons every third year.

  • Offer the comprehensive profile of laboratory tests to all comparisons. Currently, only post-1992 comparison participants get the full profile, and then only every fourth year.

  • Implement a more active program to obtain medical care records from private health care providers. The JSC Occupational Health Clinic provides no treatment for former employees. Participants are told the results of their physical exams and lab tests and referred to their private physicians for treatment of any suspected conditions. The current procedure is to simply ask participants to forward the records of those and any subsequent appointments.

  • Offer to pay for an equivalent examination to be performed at a site more convenient to the participant.

Improving the Percentage of Comparison Participants Returning to the JSC Occupational Health Clinic for Physical Exams

LSAH staff members currently send a postcard to participants about a month before they are due for a physical exam (their birthday months), asking them to call the clinic and schedule an appointment. A second contact is made by letter or phone if the participant does not respond. If the participant indicates that he or she will be unable to return to JSC for an exam, the staff requests that the participant forward medical records for any visits to personal (i.e., non-JSC) health care professionals since the previous JSC clinic exam.

Staff proposes several inducements to improve “return rate,” especially among retired civil service participants:

  • Pay travel expenses for comparison participants who no longer work at JSC and live outside the Houston area. Former astronauts who live outside the Houston area are already reimbursed for travel expenses, as are active astronauts and JSC civil servant participants, if they incur any expenses. Although the LSAH staff discussed the desirability of providing some compensation for lost wages as well, they stopped short of including that in their recommended improvement.

  • Offer to pay for an equivalent examination to be performed at a site convenient to comparison participants outside the Houston area. Occupational health clinics at other NASA centers, Federal Aviation Agency medical examiners, or private primary care providers could be given a standard protocol.

Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
×
  • Institute a publicity campaign to notify LSAH participants of the new benefit of receiving annual exams and laboratory tests comparable to those of the astronauts.

  • Implement a more active program to identify and contact individuals who miss an annual physical.

Querying the Database More Frequently and Systematically

The LSAH staff proposes to hire another senior-level epidemiologist or statistician to perform statistical analyses, guide data analysts, and review results. At present the staff is completely consumed by the process of data collection. The current staff consists of a single doctoral level epidemiologist who also serves a the project manager, 2.5 masters level epidemiologists, an administrative assistant, 2 data entry clerks, and 3 software specialists.

IOM RECOMMENDATIONS FOR CHANGE

Implementing the following recommendations, which subsume many of those offered by the LSAH staff, will inevitably involve additional expenditures, but the committee believes they are essential for the validity of the data gathered through the LSAH and ultimately for the creation of a safer space travel program.

Recommendation 1

NASA should recognize that the LSAH can and should serve the two separate and potentially conflicting goals of occupational surveillance of the health of current and former astronauts and research into the long term health risks associated with manned space flight (and make these activities safer for future astronauts).

  1. For the surveillance portion of the survey, participation of the astronauts is mandatory; for the research portion it is voluntary. Consequently, for the research portion, the astronauts need to sign an up-to-date informed consent document, and the research portion of the study should be reviewed on a regular basis by an IRB.

  2. The database should be reviewed no less often than annually by LSAH staff, and analyses should be conducted for areas of potential risk, e.g., cancers, hearing loss, cataracts, bone strength. The committee is not convinced, given the low power of the study, that traditional “statistical significance” should be the sole trigger for concern, so in addition, it recommends that routine surveillance

Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
×

for unexpected and sentinel events be carried out by the oversight committee described below.

  1. There should be a formal mechanism for flight surgeons to discuss both among themselves, and with those involved in the LSAH, any outlier or sentinel events, so that clinical suspicions are shared and checked for generality; such a system should complement the database surveillance system described above.

  2. More information should be provided to participants on emerging findings and possible risks (possibly via their examining physician). The current newsletter system could be supplemented by a clinical synopsis with an expert commentary as key findings are published.

  3. A formal process should be established to determine and implement corrective actions that follow from database surveillance or adverse event reporting. This process should enable the most learning to occur so that current and future astronauts are enabled to lead less risky lives, at least in their calling as explorers.

  4. Review the Health and Lifestyle Questionnaire regularly with outside experts and update as recommended.

Recommendation 2

NASA should recognize that no comparison group can meet every goal of the LSAH. Although use of the existing comparison group can be improved (see below), other hypothesis-specific comparison groups will be needed for definitive assessment of specific risks identified in the astronaut population. The comparison group should be seen primarily as a means to detect possible anomalies. Only after anomalies are identified can the most appropriate control group be identified and a definitive assessment of risk made. Specific suggestions for the current comparison group are:

  1. The ratio of three comparison participants for each astronaut selected should be maintained. JSC contractor (e.g., Wyle Laboratories) personnel should be added to the comparison participant pool if the civil servant population can no longer provide adequate matches for new astronaut classes;

  2. NASA should continue to seek international partner astronauts’ medical data, but we do not recommend pooling such data with the LSAH data;. Greater priority should be given to more thorough data gathering from the existing participant groups.

Recommendation 3

NASA should take steps to increase the quantity and improve the quality of the data collection and management of the data of the LSAH. The Committee was concerned by the marked variation in the content of the screening examinations that the existing LSAH groups (astronauts, retired astronauts, civil servants and retired civil servants) are currently

Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
×

receiving, by the extent of missing data in some areas, and by the lack of justification for including some screening examinations and omitting others. These issues should be reviewed in accordance with the following principle: Exact or near-exact similarity of examination content in all four groups is more important than close similarity of examination frequency. Specific steps might include:

Data Collection

  1. Pay travel expenses for comparison participants who no longer work at JSC and live outside the Houston area. Former astronauts who live outside the Houston area are already reimbursed for travel expenses, as are active astronauts and JSC civil servant participants, if they incur any expenses.

  2. Offer to pay for an equivalent examination to be performed at a site convenient to comparison participants outside the Houston area. Occupational health clinics at other NASA centers, Federal Aviation Agency medical examiners, or private primary care providers could be given a standard protocol.

  3. Institute a publicity campaign to notify LSAH participants of the new benefit of receiving physical exams and laboratory tests comparable to those of the astronauts.

  4. Implement a more active program to identify and contact individuals who miss a scheduled physical and ascertain reasons for non-participation.

  5. Implement a more active program to obtain medical care records from private health care providers. The JSC Occupational Health Clinic provides no treatment for former employees. Participants are simply told the results of their physical exams and lab tests and referred to their private physicians for treatment of any suspected conditions. Participants are asked to forward the records of those subsequent appointments with their private providers.

  6. Inflight radiation dosimetry should be state of the art and carefully recorded in the LSAH database, along with exposures of both astronauts and comparison participants in diagnostic and therapeutic settings on earth. Analyses should be carried out by categories of “radiation dose” wherever possible.

The addition of the following would enhance the value of the study:

  1. Mental health data should be added to the LSAH database.

  2. Biological specimens should be stored for future tests and studies.

Data Management

The Committee recommends several changes in the oversight structure for the LSAH:

Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
×
  1. A standing oversight committee should be established with the participation of ex-astronauts, the public, scientists of various disciplines, and independent external reviewers. The expertise needed by the oversight committee includes such areas as biostatistics, environmental health, clinical medicine, radiation biology, neurology, endocrinology, and cardiology. Principal activities of such an oversight committee should be review of the methods used to acquire and analyze the data, surveillance of the data set for unexpected events, and evaluation of plans for reacting to these events. In addition, this oversight committee should set up procedures for site review of the performance of the study analogous to that performed by clinical research organizations.

  2. At least one ex-astronaut and one or more non-NASA biomedical scientists should be added to the existing LSAH Executive Committee.

  3. Additional professionals (e.g., epidemiologist) and staff should be hired as necessary to keep the database current and meet the new review and reporting requirements described above.

Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
×
Page39
Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
×
Page40
Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
×
Page41
Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
×
Page42
Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
×
Page43
Suggested Citation:"4 Recommendations for Changes in Study Design and Execution." Institute of Medicine. 2004. Review of NASA's Longitudinal Study of Astronaut Health. Washington, DC: The National Academies Press. doi: 10.17226/10903.
×
Page44
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As part of its ongoing commitment to the nation's space program, NASA's medical leadership asked the Institute of Medicine (IOM) to review specific aspects of the scientific basis, policies, and procedures associated with the Longitudinal Study of Astronaut Health (LSAH). NASA created the LSAH in 1992 to address a variety of issues, including both the health of astronauts during space flight and the longer-term health issues that might be associated with space flight and flight training.

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