"After the study is completed, we will retain your anonymized data"
Some thoughts about studies involving sensitive subjects and privacy.
First off, as privacy activists know, there is no such thing as "anonymized data". Each data point can make it easier for someone to deanonymize someone.
That is just something to keep in mind.
If that is a worry, then for starters, someone could avoid collecting superfluous data, or maybe for something like an age, they could collect an age range instead of a specific number (unless, that precision is needed).