Our study of the long term health effects of participation in project shad shipboard hazard and defense posed a number of challenges including difficulties in identifying all the project shad participants assembling an appropriate control group devising and administering a suitable survey instrument and producing a sound analysis and accompanying report. Long term health effects of participation in project shad shipboard hazard and defense washington dc the national academies press doi 1017226 11900 x save cancel 11 discussion the studys strengths and weaknesses strengths the quality of a study of this magnitude and complexity is not easily characterized the strengths of this study include a relatively large initial cohort . Long term health effects of participation in project shad shipboard hazard and defense washington dc the national academies press doi 1017226 11900 x save cancel 6 referent cohort general scheme we decided on a two stage scheme for selecting nonparticipant controls for study personnel on ships we began first by selecting a matching control ship for each participant ship we . In september 2002 the institute of medicine iom agreed to undertake a scientific study funded by the veterans affairs of potential long term health effects of participation in project shad in general there was no difference in all cause mortality between project shad participants and nonparticipant controls although participants statistically had a significantly higher risk of death due to heart disease had higher levels of neurodegenerative medical conditions and higher rates of . Long term health effects of participation in project shad shipboard hazard and defense william f page heather a young and harriet m crawford authors with oversight from the advisory panel for the study of long term health effects of participation in project shad isbn 0 309 66090 4 142 pages 8 1 2 x 11 2007