There's a reported correlation between sun damage and GD. Never used a tanning bed, but lived at the ocean and always in the sun. I'm 70 and the only sunscreen we had growing up was zinc oxide we put on our noses and a shirt when we realized we were fried. Typical cycle beginning in late spring- deep sunburn, peel, another sunburn, peel, sunburn and peel and after that the skin just managed it without significant burning and no more peeling until fall when beach weather cooled down we went back to school.