Tanner Staging

Pubertal progression was assessed by clinical examination of breast development in girls, genital development in boys, and pubic hair development in both as proposed by Marshall and Tanner (38). Development was classified into 5 stages of breast (B1–B5), genital (G1–G5), and pubic hair (PH1–PH5) with stage 1 defined as pre-pubertal and stage 5 representing adult development (39). Physical exams were conducted by staff trained by a pediatric endocrinologist. In girls, pubic hair development was assessed visually while breast development was determined by palpation of the breasts to distinguish adipose tissue from glandular breast tissue (40). Onset of puberty was indicated by the development of breast buds (B2). Menarche was determined by self-report. Specifically, at each visit beginning at age 9, the girls were asked if they had started menstruating. For boys, stages of genital and pubic hair development were conducted by visual assessment followed by a physical measurement of testicular volume using Prader orchidometer beads for comparison. Puberty onset is signaled by the initial enlargement of the scrotum and testes (G2), testicular volume of 3 ml or more, or androgenic stimulation of pubic hair development (PH2).