When you lift a lot your intervertebral disks get smaller because of the pressure and destruction caused be too much pressure. Also, you loose the body fat surrounding many of your organs and the fat under the skin e.g. in your feet (bottom part).
Is this the reason that extreme bodybuilding make you shorter in the end?
Or are there other factors that compensate this lose caused by damaged intervertebral disks and fat loose?
The loss of height from compressed discs is most likely negligible even over the long term. Over the course of a normal day spinal discs will compress, but spring back during normal sleep. Even under high loads, the spinal discs will spring back relatively quickly - this being part of their primary function.
Regarding weight loss and height loss, I've never seen any research studying this. However, fat lose could cause a marginal (sub-centimetre) loss in height, however this would most likely be offset by a similar corresponding height increase caused by less body weight compressing the spine.
Either way, while I find it difficult to believe that weightlifting and weight loss could cause a measurable change in height, I couldn't find any evidence to back it up.
If you think you've gotten shorter, it may just be a change in posture. Pelvic tilt, which can be caused by poor posture or imbalanced training of either the anterior or posterior chain can cause a noticeable change in height, among other things.
The fact that body-building stunts growth--or worse, actively makes you shorter--is a myth. It likely grew out of the fact that over-aggressive weight-lifting can cause injury to the ephiphyseal (i.e., "growth") plates in those who have not finished growing. But injuring a growth plate doesn't actually stop that bone from growing, it simply creates a usually small anomaly in the bone just like any other bone injury. Osgood-Schlatter's disease in which the patellar tendon pulls--and sometimes pulls off--the tibial growth plate is a common teen weight-lifting injury. If O-S stunted tibia growth, there would be a lot of folks walking around with one leg longer than the other.
If you really are getting shorter, that is the result of something else which could be related to weight-lifting or not. People do get shorter as they age as a result of loss of cartilage in the spinal discs, relaxation of the foot-arch ligaments, and consequent posture changes.
I don't think bodybuilding can make you shorter. On the contrary, it can lead to an increase in your HGH production which can help enhance your height (of course, it depends on your age too)
