alt Hacker NewsPeople do tend to shrink in height quite a bit at advanced age.
https://medlineplus.gov/ency/article/003998.htm
"People typically lose almost one-half inch (about 1 centimeter) every 10 years after age 40. Height loss is even more rapid after age 70. You may lose a total of 1 to 3 inches (2.5 to 7.5 centimeters) in height as you age."
So people DO in fact tend to lose about 2 inches at age 80 versus their younger selves.
The actual studies [1],[2] that tried to measure this came to very different rates of height loss though: 3.6 cm and 6 cm from 40 to 80 in men. This does not look like a serious fact.
1. https://pubmed.ncbi.nlm.nih.gov/10547143/
2. https://www.mdpi.com/2072-6643/15/21/4694 (referencing the FHS there, the numbers are hard to find on the study's website).