What categories of people are more at risk?
As a group, women are more at risk than men. There are several reasons for this. Women tend to do more of the repetitive computer tasks than men do. They also have less muscle mass than men have, and a greater percentage of women fall outside the height range considered the norm. The further you are from the standard, or "average" male that most office furniture was designed for, the more risk you have.
Are there any other factors that should be considered?
Yes, there are also genetic factors. As with many other injuries, some people have a genetic predisposition to getting them. Another factor is how your work at the computer is accomplished during a day. Consider two people doing the same number of keystrokes in the same amount of time at a computer. One sits down for three hours and works nonstop. The other breaks up the work into multiple sessions. The person who does all the work at one time is more at risk for CTS and RSI.
How does repetition fit in?
Think of this like you would some other cumulative-type diseases. It is not one french fry that gives you heart disease, rather it is the cumulative effect over a number of years. The cumulative effect varies in its impact on different people. It is performing the same movement over and over with too much force and/or too awkward a position that starts to add up.
Does everyone have the same risk of Carpal Tunnel Syndromeand Repetitive Stress Injuries?
No, the risk is not the same for everyone. However, there are some categories of computer users who are more at risk than others. Consider the fact that most office furniture is one size fits all. If you lined up computer users in your office, they are going to be all shapes and sizes, yet they all sit at the same standard office furniture whether it fits them or not.