Cross-sectional studies in samples of Sikhs resident in Britain show that pigmentation increases in early life to the preadolescent stage, and thereafter diminishes to adulthood. These trends appear more regular in females than in males. The physiological mechanisms responsible for them are discussed, and it appears that age-related variations in melanocytes, in hormonal variation, and delay in maturity of melanogenic activity in infants are the primary factors responsible.
Kahlon, D P.S
"Age Variation in Skin Color: A Study in Sikh Immigrants in Britain,"
3, Article 1.
Available at: https://digitalcommons.wayne.edu/humbiol/vol48/iss3/1