I’ve recently came across an interesting article published in the 2002 Arch Dermatol journal called Acne vulgarism: a disease of Westernized civilization.
Some interesting facts where that 79-95% of adolescents in Western societies experience some form of acne, and approximately 40-54% of adults will experience some degree of acne .
The study looked at two nonwesternized tribes, Kitavan subjects in Papua New Guinea and Ache hunter and gather tribe in Paraguay. The study found no acne cases present in these two tribes. The study followed the Ache tribe for 843 days and did not find one acne case!!!!
Possibly explanations include genetics, low glycemic index/load diet and dairy-free diet. I think it’s an interesting study, as it demonstrates the impact of diet on skin health.
 Cordain L et al. Acne vulgaris: a disease of Western civilization. Arch Dermatol. 2002 Dec; 138 (12)” 1584-90.