Whilst celebrities have access to everything money can buy, unfortunately, like us mere mortals, they can succumb to the rigours of aging, including height loss.
Studies have been done in the past on typical loss of height but results I've seen vary. A recent study revealed the following:
"To determine the magnitude of height loss that accompanies aging, longitudinal studies are required. The authors studied 2,084 men and women aged 17-94 years enrolled from 1958 to 1993 in the Baltimore Longitudinal Study of Aging, Baltimore, Maryland. On average, men's height was measured nine times during 15 years and women's height five times during 9 years. The rate of decrease in height was greater for women than for men. For both sexes, height loss began at about age 30 years and accelerated with increasing age. Cumulative height loss from age 30 to 70 years averaged about 3 cm (1.18 inches) for men and 5 cm (1.97 inch) for women; by age 80 years, it increased to 5 cm for men (1.97 inch) and 8 cm (3.15 inches) for women"
Another study which covered a 20-year period of nearly 8000 men showed men lost on average 0.66 inches (1.67cm), with samples in the initial age range being 40-59 and final height 20 years later taken when they are 60-79.
Sometimes the results of shrinking can be drastic, other times celebrities barely shrink at all. The reasons for loss of height can range from bad posture (hunching), osteoperosis resulting in fractures, surgeries like knee and hip replacements, curvature of the spine. Some noticeable cases of stars shrinking are Ann Miller (5ft 7 to 5ft 3), Clint Eastwood (6ft 4 to 6ft 1), Hulk Hogan (6ft 6 to 6ft 4), James Garner (6ft 2.5 to under 6ft), Charlton Heston (6ft 3 to under 6ft). I will usually give a peak/current height for celebrities who are still in the public eye. If they've retired from acting and are out of the spotlight, I will just leave at their peak height.