I guess it is possible that you will shrink a tiny bit in the short run, if you do not manage to maintain muscle mass that suports your spine. But on the long run you could even more likely maintain height (and length ...

) compared to your same aged buddies because you would not have a more sudden loss in muscle mass later in age. Also I imagine that the spinal discs should not loose in size so much as you age. (Probably through reduced collagen cross links) But that is all speculation.
Did any of you long term CR practioneers shrink?