Normal ages of pubertal events among American males and females

JOURNAL OF ADOLESCENT HEALTH CARE 1:26-29,1980

Normal Ages of Pubertal Events Among American Males and Females P E T E R A. LEE, P h . D . , M . D .

This study identifies the mean and standard deviations of the chronologic age of the attainment of a variety of important events of puberty in American males and females. The information is based on longitudinal observations at 6-month intervals with the first observation of each particular pubertal characteristic being documented within 6 months of its appearance. The mean (---SD) ages of pubic hair and genital or breast stages, and onset of peak weight gain, peak height velocity, acne and axillary hair are given for both sexes. Menarche is documented for females, and gynecomastia, voice break and change, and facial hair for males. These data show the range of individual age variation of normal pubertal events. Puberty may begin from age 8.0 to 14.9 years for females and from age 9.7 to 14.1 years for males and is complete by age 12.4 to 16.8 years for females and by age 13.7 to 17.9 years for males.

percentage of individuals at various stages of puberty according to age (3,4). A recent paper indicates the average stage of sexual development for males from ages 12 to 17 years as part of a comparison of genital, pubic hair, and skeletal maturation (5) and does not give the mean ages of attainment of pubertal stages nor the mean intervals between them. The current report is designed to identify the chronologic age of occurrence of events of female and male puberty collected in a longitudinal fashion based on examinations every 6 months. The age of occurrence of the stages of female and male puberty and other associated pubertal changes that occur in some or all subjects are noted. The purpose is to characterize the range of variability in attaining the various stages of puberty.

KEY WORDS"

Acne Body weight Breast development

Genitalia Growth Puberty

Materials and Methods

A decade ago, reports from Great Britain documented the normal mean age and range of attainment of the pubertal stages of breast and pubic hair development for females (1) and genital and pubic hair development for males (2). These studies also reported the age of peak height velocity for both sexes and menarche for females. There are no comparable studies based on subjects in the United States, although studies of the variation of physical changes of puberty have indicated the From the Department of Pediatrics, The Johns Hopkins University and Hospital, Baltimore, Maryland. Direct reprint requests to: Peter A. Lee, M.D., 32-110 Children's Medical Center, The Johns Hopkins Hospital, Baltimore, MD 21205. Manuscript accepted February 8, 1980. 26 TSSN 0197-0070/80/010026-04/$02.25

Thirty-six males and eighteen females were examined at 6-month intervals during a 5-year period ending in 1974. The age of attainment of the various evidences of pubertal development were determined. Females were from 8.6 to 17.8 years of age and males from 9.2 to 17.5 years. Ninety-four percent were white. These subjects were from a normal healthy group who volunteered from a school population of primarily upper-middle socioeconomic status. Written informed consent was obtained from the parents. Determinations among females included breast and pubic hair stages (1), height, weight, the presence of acne and axillary hair, and a menstrual history. Among males, designations were stage of pubic hair and genital development (2), height, weight, and the presence of acne, axillary hair, gynecomastia, facial hair, and the first noted break in voice pitch and

© Society for Adolescent Medicine, 1980 Published by Elsevier North Holland, Inc., 52 Vanderbilt Ave., New York, NY 10017

S e p t e m b e r 1980

N O R M A L A G E S OF PUBERTAL EVENTS

first noted persistent change in voice pitch. Height was measured using a right angle device against a stationary vertical ruler. All determinations were made by the author without the availability of previous data. The calculation of the mean ages for the attainment of various milestones of pubertal development is based on the age w h e n the presence of new or progressed

T a b l e 1. T h e M e a n ( + S D ) A g e s ( Y e a r s ) o f t h e V a r i o u s Pubertal Events in American Adolescents Pubertal e v e n t a

Females

Males

Br 2 G 2 PH 2 G 3 Gynecomastia Voice break Peak h e i g h t velocity Peak w e i g h t gain Axillary hair Br 3 Menarche PH 3 Voice c h a n g e Acne G 4 Regular menses PH 4 Br 4 Facial hair Br 5 G 5 PH 5

11.2 + 1.6 11.9 + 1.5

12.5 12.4 13.1 12.4 13.3 12.7

± ± ± ± ± ±

1.5 1.4 0.8 1.2 1.3 0.5

13.2 ± 0.5 13.9 ± 1.0 13.4 + 1.2 13.1 ± 0.7

11.9 12.3 13.2 13.2 13.5 13.8 13.9 14.0

+ + + + + -~ ± ±

1.1 0.8 0.8 0.8 1.0 1.1 0.9 1.1

13.9 14.1 14.3 14.3

± ± ± -+

0.9 0.9 1.3 0.8

14.7 ± 0.9 14.9 ± 1.1

14.5 -+ 1.6 15.1 -+ 1.1 15.3 ± 0.8

14.6 -+ 1.1

aBr = breast, G = genital, P H = p u b i c hair.

T a b l e 2. M e d i a n A g e o f A t t a i n m e n t o f t h e V a r i o u s Attaining Each Event at Selected Ages

development was observed in comparison with a previous examination in which such development was not present. The male data are also presented to show median ages and the percentage of subjects who had obtained a given milestone of puberty at the various ages.

Results This study provides two sets of data. First is the actual age of observed pubertal events among the males and females. Because subjects entered the study at various points of pubertal development and some features such as acne and gynecomastia are not present in all subjects, each mean age does not include all subjects. Age of each pubertal event was documented among a mean of 24 of the 36 males and 11 of the 18 females. Second is the actual observed mean --- SD from the onset of puberty to other pubertal events based on evaluations every 6 months. Adequate data (N = 6-11) among females were limited to 5 intervals; intervals among males are more extensive, each group consisting of 7 to 24 observations (mean = 14). The mean + 2 SD observed ages of pubertal events among females and males are listed in Table 1 and allow a comparison of the relationship of and overlap between the normal age range of the occurrence of the various pubertal events. Table 2 shows the median and percentage of the sampled male population who had reached pubertal milestones at various ages. Actual observed mean + SD intervals between

Pubertal

Events

Among

American

Males with the Percentage

Pubertal

Median

event ~

a g e (years)

10.0

11.0

11.5

12.0

12.5

13.0

13.5

14.0

14.5

15.0

G 2 PH 2 G 3 Voice break Peak w e i g h t g a i n PH 3 Axillary hair Peak h e i g h t velocity Voice c h a n g e Acne G 4 PH 4 Facial hair PH 5 G 5

12.2 12.6 13.4 13.5 13.7 13.9 13.9 13.9 14.0 14.4 14.4 14.8 15.0 15.1 15.5

10

19 9

24 17

48 26 4 7

67 44 23 21 9 8 13 17 4 9

81 70 42 43 15 16 17 34 15 21 4

95 78 65 50 41 44 38 43 37 29 13 5 20 8 4

95 85 74 56 56 58 54 48 38 42 27 30 16 17

96 86 74 72 75 74 74 56 54 45 40 25 22

89 88 96 88 89 81 74 88 72 50 42 35

~G = genital, P H = pubic hair.

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Percentile A t t a i n m e n t b y C h r o n o l o g i c A g e (years) 15.5

16.0

16.5

94 92 91 96 82 96 86 70 75 51

96

88

94

95 85 83 78

95 92 96

28

LEE

JOURNAL OF ADOLESCENT HEALTH CARE Vol. 1, No. 1

T a b l e 3. Mean (+ SD) Observed Intervals Between the

Onset of Pubertal and Other Events in American Males Interval (years) Pubertal eventa PH 2 Voice break Gynecomastia G3 Peak weight gain Axillary hair Voice change Acne Peak height velocity G4 Facial hair PH5 G5

After G 2 0.8 1.0 1.2 1.3 1.8 1.9 2.0 2.0 2.0 2.3 3.1 3.6 3.6

± 0.8 + 0.6 -+ 0.6 -+ 0.4 ± 0.8 -+ 0.9 ± 0.8 ± 0.9 ± 1.0 ± 0.5 ± 0.4 ± 0.2 ± 0.6

After PH 2 -0.5 ± 0.5 0.4 + 0.7 PH3 1.2 ± 0.3 1.4 ± 0.4 1.3 -+ 0.6 1.3 ± 0.8 1.6 ± 0.6 1.7 ± 0.6 PH42.0 ± 0.4 2.3 ± 0.7 2.6 ± 0.6 2.8 ± 0.6

aPH = pubic hair, G = genital. the a t t a i n m e n t of the T a n n e r b r e a s t (Br) a n d p u b i c hair (PH) stages a m o n g females w e r e as follows: Br 2toPH2 =0.3---0.3;Br2toBr3 = 1.0 + 0 . 3 ; B r 2 to Br 4 = 1.8 + 0.4; P H 2 to P H 3 = 1.0 - 0.3; a n d P H 2 to P H 4 = 1.8 + 0.3 years. Table 3 p r o v i d e s m e a n + SD intervals after the o n s e t of p u b e r t y to the other p u b e r t a l e v e n t s for males. The m i n o r differences b e t w e e n the calculated m e a n intervals a n d the differences in age b e t w e e n the s a m e t w o e v e n t s are d u e to the determ i n a t i o n s b e i n g m a d e at 6 - m o n t h intervals a n d differences in s a m p l i n g . O n l y t h o s e instances in w h i c h b o t h e v e n t s w e r e o b s e r v e d are included.

Discussion The data p r e s e n t e d identify the age r a n g e of att a i n m e n t of a variety of p u b e r t a l e v e n t s plus the m e a n interval after the o n s e t of physical p u b e r t y to o t h e r p u b e r t a l milestones in a l o n g i t u d i n a l s t u d y s a m p l i n g n o r m a l A m e r i c a n children. H o r m o n a l studies of a m a j o r p o r t i o n of this p o p u l a t i o n h a v e b e e n p u b l i s h e d e l s e w h e r e (6,7). Because d e v e l o p m e n t a l features m a y p r e s e n t w i t h a s k e w e d distribution of the age-ofa t t a i n m e n t , w i t h a w e l l - d e f i n e d l o w e r limit a n d central t e n d e n c y b u t a tail to the right, the p e r c e n t age a t t a i n m e n t table in relation to chronologic age of m a l e s (see Table 2) has b e e n included. T h e s e data for m a l e s indicate that the limits of p u b e r t a l e v e n t s are essentially the s a m e as indicated b y 2 s t a n d a r d deviations a r o u n d the m e a n , a l t h o u g h in s o m e instances, the m e d i a n e v e n t occurred s o m e w h a t later t h a n the m e a n a n d the 95 or 96% slightly later t h a n the m e a n - SD, e.g., P H 2 a n d genital stage 4 (G 4).

This s t u d y w a s d e s i g n e d so t h a t the data collected w e r e similar to those in the usual setting for the e v a l u a t i o n of adolescents, i.e., periodic examinations. Because e x a m i n a t i o n s in this s t u d y w e r e e v e r y 6 m o n t h s , the age at w h i c h a stage w a s a t t a i n e d is the age at the e x a m i n a t i o n in w h i c h the stage w a s first noted. Also b e c a u s e the interval w a s 6 m o n t h s , the error for a n y g i v e n individual could r a n g e u p to 6 m o n t h s , w i t h a n a v e r a g e error of 3 m o n t h s . The actual age of a t t a i n m e n t m a y thus be 3 m o n t h s y o u n g e r t h a n that indicated here, but, b e c a u s e the utilization of the data is b a s e d o n periodic evaluation, s u c h data are applicable. The m e a n a n d SD of p u b e r t a l e v e n t s c o m p a r e s reas o n a b l y w i t h the p u b l i s h e d data f r o m G r e a t Britain (1,2). A m o n g females, P H 2, P H 5, a n d p e a k height velocity occurred, respectively, 0.2, 0.2, a n d 0.4 y e a r s later a m o n g this s a m p l e t h a n a m o n g the English s a m p l e (1). Male m e a n s for G 2 a n d 5 a n d for P H 2 a n d 5 are, respectively, 0.5, 0.2, 0.3, a n d 0.1 y e a r s later t h a n t h o s e r e p o r t e d in the English s t u d y (2). T h e s e differences are not statistically significant. The differences are d u e in p a r t to the fact that the p r e v i o u s l y p u b l i s h e d English data are b a s e d o n 3 - m o n t h l y o b s e r v a t i o n s , w h e r e a s the curr e n t s t u d y is b a s e d on 6 - m o n t h l y observations. T w o s t a n d a r d deviations a r o u n d the m e a n for this s a m p l e of A m e r i c a n females identifies the age r a n g e for the o n s e t of b r e a s t d e v e l o p m e n t to be b e t w e e n 8.0 a n d 14.4 years. Pubic hair m a y first a p p e a r f r o m 8.9 to 14.9 y e a r s of age. D e v e l o p m e n t of breasts m a y be c o m p l e t e f r o m age 11.3 to 17.7 y e a r s a n d adult pubic hair m a y first be p r e s e n t f r o m 12.4 to 16.8 y e a r s old. This indication of n o r m a l r a n g e s s h o w s that s o m e females m a y c o m p l e t e p u b e r t y before others of the s a m e age h a v e b e g u n . Pubic hair m a y g r o w before breast d e v e l o p m e n t is a p p a r e n t . In s o m e instances the m e a n p e a k height velocity (PHV) p r e c e d e s breast d e v e l o p m e n t b y as m u c h as 1 year, a l t h o u g h in others it does not occur until 1.7 y e a r s later. In all the a u t h o r ' s observations, h o w e v e r , P H V occurred w i t h i n 6 m o n t h s of the a p p e a r a n c e of p u b i c hair. M e n a r c h e occurs f r o m 1.2 to 2.8 y e a r s after breast d e v e l o p m e n t is a p p a r e n t , a l t h o u g h the r a n g e m a y be c o n s i d e r a b l y greater, since a larger s a m p l i n g (1) f r o m a n o t h e r s t u d y indicated that the interval m a y be as great as 5.8 years. The a v e r a g e age of m e n a r c h e is higher t h a n expected, likely d u e to a small a n d p o o r l y r e p r e s e n t a t i v e s a m p l e . In A m e r i c a n males, p u b e r t a l genital g r o w t h m a y first be e v i d e n t b e t w e e n a b o u t 9.7 a n d 14.1 y e a r s of age a n d adult genital d e v e l o p m e n t m a y be exp e c t e d b e t w e e n ages 12.9 a n d 17.3 years. Pubic hair

September 1980

may first be present from about age 10.5 to 14.1 years, with adult patterns from 13.7 to 16.9 years. As among females, some males may be prepubertal while others of the same a g e have completed puberty, according to either developmental scale, yet fall within the normal range of development. The greatest growth rates, both in height and weight gain, occur in the average male about 2.0 years after the first evidence of puberty. Maximal weight gain followed the first evidence of puberty, while the greatest linear growth velocity in some instances occurred simultaneously with the onset of puberty. The usual sequence after the onset of genital growth is the appearance of pubic hair about 6 months later, followed in about a year by the first noted crack or break in voice pitch and, in some, gynecomastia. Two years later the growth peaks and permanent voice change and acne occur; 3 years later, the onset of facial hair begins. Table 1, however, shows that the relative sequence of these events may vary considerably among normal individuals. This pattern of the attainment of genital and pubic hair stages and peak height velocity is similar to that reported in 1970 for males in Great Britain (2). The average female experiences the onset of puberty 0.5-1 year earlier than the average male and completes puberty at a comparable age difference. This difference is consistent with that found earlier (2), particularly if it is recognized that in the British study, the onset of pubic hair growth was not accurately determined and that photographs were used for staging. This study confirms the

NORMAL AGES OF PUBERTALEVENTS

29

previously recognized sex difference in the relationship of the extent of pubertal development and the adolescent growth spurt (2), with the female usually growing maximally in height while in stage 2 of breast development and closer to the onset of puberty than among males, who grow most rapidly during mid-puberty. This study points out the considerable variation of the ages at which various pubertal events occur among American youth and suggests guidelines for normal individual variation.

References 1. Marshall WA, Tanner JM: Variations in the pattern of pubertal changes in girls. Arch Dis Child 44:291-303, 1969 2. Marshall WA, Tanner JM: Variations in the pattern of pubertal changes in boys. Arch Dis Child 45:i3-23, 1970 3. Reynolds EL, Wines JV: Individual differences in physical changes associated with adolescence in girls. Am J Dis Child 75:329-350, 1948 4. Reynolds EL, Wines JV: Individual differences in physical changes associated with adolescence in boys. Am J Dis Child 82:529-547, 1951 5. Harlam WR, Grillo GP, Corononi-Huntley J, et al: Secondary sex characteristics of boys 12 to 17 years of age: The U.S. Health Examination Survey. J Pediatr 95:293-297, 1979 6. Lee PA, Migeon CJ: Puberty in boysi Correlation of serum levels of gonadotropins (LH, FSH), androgens (testosterone, androstenedione, dehydroepiandrosterone , and its sulfate), estrogens (estrone and estradiol) and progestins (progesterone, 17-hydroxy-progesterone). J Clin Endocrinol Metab 41:556-562, 1975 7. Lee PA, Xenakis T, Winer J, et al: Puberty in girls: Correlation of serum levels of gonadotropins, prolacfin, androgens, estrogens, and progestins with physical changes. J Clin Endocrinol Metab 43:775-784, 1976