Acrophobia effects people of all ages, genders, social classes, races, and religions. There is no specific sector that it affects, so you might say it can hit anyone at any time. It is more likely to affect someone who has been through a trauma involving heights or has witnessed someone else going through a trauma or those who have high stress and anxiety levels in the first place. Still, it can come upon anyone at random. There is no rhyme or reason for it much of the time. It is a baffling disorder, for sure.
It comes from within the brain and how the signals within the brain respond to stimuli. Some brains revert to the primitive, or old brain, the message of flight or fight when stimuli such as being up high are introduced. This causes other parts of the brain to send out the message that there is a danger which can produce high anxiety and even physical symptoms. There is no specific age, race, or any other factor that determine who does and does not suffer from this phobia but there are factors that can cause one to be more susceptible than another to get it.