The Longitudinal Study of Astronaut Health (LSAH) originated as a research study in 1989 to examine the incidence of acute and chronic morbidity and mortality of astronauts to determine whether the unique occupational exposures encountered by astronauts are associated with increased risks of total or cause-specific morbidity and mortality.
Specifically, the primary a priori hypotheses to be tested were: 1) astronauts are at different
risk of total morbidity (defined as rate of incident cases of diseases/disorders, rate of
hospitalizations, and average number of hospitalization days per person), than ground-based
employees; and 2) astronauts are at different risk of total mortality than ground-based employees.
All astronauts selected for the NASA astronaut program were followed as "exposed" subjects from
selection through-out the course of the study.
The Longitudinal Study of Astronaut Health
(LSAH) was a designed as a cohort study, and risk was measured relative to civil service employees
located at the Johnson Space Center (JSC) who worked and lived, at least for a time, in the same
geographical area as the astronauts. All cohorts volunteered to participate in the study.
Civil service employees who received routine annual physical examinations at the JSC Occupational
Medicine Clinic were selected as comparison subjects using age, sex, and body mass index as
selection criteria, and they were followed in the same manner as the astronauts. As new
astronauts were selected, matching groups of comparison participants were identified and
recruited. The ratio of participants was three comparison subjects for every one astronaut,
later changed to a ratio of 5:1. Morbidity, mortality, physical examination, and laboratory
data were collected utilizing medical records routinely collected at the Johnson Space Center,
as well as medical consultant reports, hospital discharge summaries, death certificates, and,
when available, autopsy reports.
Analyses on the LSAH data continue to be performed though
the research study was closed and comparison subjects were released in May 2010. The LSAH databases are useful
as computerized medical records as well as for research purposes. The personal medical data
included in the data bases of the LSAH are protected by the Privacy Act of 1974, as amended,
by the HIPAA (Health Insurance Portability and Accountability Act (HIPAA) of 1996
(Public Law 104-191)), and by the additional security procedures and policies of NASA, the LSAH
and the JSC Clinics. Individual participant data are not included in reports or publications;
only grouped data are presented.