What functions affect adoption of Applewatches for the elderly people?

Recently, I have been investigating the old people’s use of Apple Watch, but I am not sure about the research method. As the old people are a special group, it is difficult to recruit them, especially those who use Apple Watch. One thing that was not so clear was whether there would be a fee to pay for a Prolific of old people to be advertised to the website. Considering that the interview will be conducted offline, but it is difficult to find the old people who use apple Watches. Please help me figure out how to do it。