I wouldn't think that its the juice. I think its more time and physical activity. Getting older and weigfht training puts stress on bones, especially the weight training. The impact on the disks in the back over years will cause them to supress and not have as much bounce in them. I think this is what maybe the cause, along with time and deterioration.
Its possible. As you get older you shrink in height!! But you aren't that old are you? You didn't step on any land mines in the past few years have you?? Also, you can vary upto an inch in height from the time you wake up, to the time you go to bed. Your cartaledge will compress as the day goes on, so you are tallest in the morning.