health disparities and health inequities are different things. disparities, like higher incidence of certain diseases, can be the result of health inquities. it goes beyon ethnicity/race and SES as well... for example, people in rural communities have less access to care, especially specialty services. if you are just trying to use the issue to sound great in your interview because it is a "hot topic", you might actually do yourself a disservice.if you cannot point to any experiences you've had, you will have to stick with the token "I have some interest and might pursue that route". but considering you don't really know what it is makes me think you just want to sound empathetic or something to increase your chances of getting accepted.
as for a current events type question in an interview, I suggest reading about the changes that will be coming regarding quality of care, reimbursement for services, and how quality will actually be quantified.