The humans have polluted the environment. And this pollution directly causes damage on our hair. The hair is the primary organ that is affected in types of diseases.
If someone is going through chemotherapy, then the hair falls out. It also falls out due to seasonal changes, when the weather is hot, etc. Therefore, the first source for the changes in our hair is ourselves.
In the short term, the care or chemicals we apply on our hair can cause changes in our hair. Especially young women dye their hair which means that the structure of the pigments inside the hair are changed. If you cause change in this structure often, then after a while the hair has brittle or turns gray because the pigment dyes after a while.
If the hair is often straightened using hair blow, or curled using a curling iron, then we damage the outer layer of the hair and the hair is damaged furthermore.
If one has a scalp disease and does not get it treated, then the hair will be damaged.
Therefore, I believe if we can take good care of our bodies, and our hair, any structural changes on the body will be disappear.