For these reasons, this report neither explores nor addresses all the interesting facets of possible exposure-outcome associations. It can, therefore, neither reassure nor vindicate those who feel strongly about the nature of many of those associations. Areas of inquiry into which we have not delved in this study but for which we could imagine a study design include:
- exposure-outcome analyses based on exact dosimetry estimates calculated for a subset of the overall study population;
- fuller examination of cause of death, looking beyond the underlying cause to all associated or contributory causes listed on the death certificate; and
- detailed analysis of the participants who served in the Marines and Army (including the Army Air Corps) in CROSSROADS and their controls.
Unfortunately, the following group of topics may never be well studied in this observational cohort due to reasons including very small numbers; the nonexistence of necessary exposure information; and the unfeasibility, if not impossibility, of tracking health outcomes other than death:
- unique aspects, if any, of the exposure-outcome relationship in women;
- possible effects of participation or other measures of exposure on outcomes other than mortality, looking at morbidity rates for the diseases considered in the mortality study (e.g., skin cancer) and for other diseases and conditions believed to be radiogenic (e.g., cataracts);
- adverse reproductive outcomes;24
- more finely defined categories of military occupation, for officers and non-Navy enlisted personnel for whom no occupation data is available; and
- the interrelationships of other, non-CROSSROADS, risk factors accruing before, during, and after the Operation CROSSROADS activities, including an overlapping array of exposures that could be chemical and physical (occupational, environmental, behavioral); socioeconomic (education, income, occupation); geographic; and medical (comorbidities). Not the least of these is the possibility that many of the participants, as a result of their special radiological training for Operation CROSSROADS, may have gone on to careers associated with radiation.