I have dpa and the hair transplant surgeon I get my proscar script from told me it is possible a thyroid issue is the cause of my hair loss. He's the one who convinced me to get my thyroid checked, he said he's never seen anyone lose eyebrow hairs like I do from proscar so it very well could be my thyroid causing my hair loss problems.
My family has more of a history of thyroid problems then hair loss, I have only one uncle with hair loss on my mothers side which also has the thyroid problems.