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Changes in vitamin D and matrix metalloproteinase-9 in submariners during a submerged patrol
  1. A Baker1,
  2. C L Wood2,
  3. A M Wood1,
  4. P Timms3,
  5. A J Allsopp1
  1. 1Institute of Naval Medicine, Alverstoke, Hampshire, UK
  2. 2Department of Child Health, Newcastle Hospitals Foundation Trust, Newcastle upon Tyne, UK
  3. 3Department of Clinical Biochemistry, St Bartholomew's Hospital, London, UK
  1. Correspondence to Dr C L Wood, Department of Child Health, Newcastle Hospitals Foundation Trust, Newcastle upon Tyne NE1 4LP, UK; claire.wood{at}


Objectives To quantify changes in vitamin D and matrix metalloproteinase-9 (MMP9) in submariners over a single long patrol and compare the data to a group of non-deploying servicemen from their base port.

Methods A prospective time-series analysis was performed. Blood samples were taken from 49 submariners deploying on patrol and 43 shore-side controls from the base port (naval officers from base or non-deploying submariners), following a winter ashore at latitude 56° north. Samples were drawn immediately before the submarine sailed, in January, and again in the final week of patrol 85 days later. Paired pre-patrol and late samples from each individual were assayed together and changes in vitamin D and MMP9 were assessed.

Results Mean pre-patrol vitamin D concentrations were 58 and 49 nmol/L for the controls and submariners, respectively. Mean vitamin D concentrations increased in controls as expected (mean increase 12.6 nmol/L), but not in the submariners (mean decrease 1.6 nmol/L). MMP9 levels were significantly higher in submariners pre-patrol, and increased significantly during the patrol. There was a significant inverse correlation between MMP9 and vitamin D levels (r=−0.41, p=0.01).

Conclusions This is the first study to quantify vitamin D and MMP levels in submariners. Circulating vitamin D concentrations on board were insufficient to prevent a rise in MMP. This has potential for adverse health effects and requires further study.

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