ANNALS OF HUMAN BIOLOGY,
1991, VOL. 18, NO. 1, 4 7 - 5 6
Height and height velocity in early, average and late maturers followed to the age of 25: a prospective longitudinal study of Swedish urban children from birth to adulthood U. HAGG t
and J. TARANGER*
Ann Hum Biol Downloaded from informahealthcare.com by Mcgill University on 11/03/14 For personal use only.
tDepartment of Orthodontics, Faculty of Odontology, University of Lund, MalmO, Sweden; and Department of Children's Dentistry and Orthodontics, the Prince Philip Dental Hospital, University of Hong Kong, Hong Kong *Department of Pediatrics I, Faculty of Medicine, University of Gtiteborg, Sweden Received 11 April 1989; revised 13 July 1990
Summary. A sample of 103 Swedish boys and 80 Swedish girls followed longitudinally were grouped into early, average and late maturers on the basis of age at peak height velocity. In girls there were significant differences in height between the maturity groups from 5 to 14 years of age, but the final height did not differ between the groups. In boys there were significant differences in height between the maturity groups from 12 to 16 years, no significant difference at the age of 17 years, and from 18 years of age and on, late-maturing boys were significantly taller than the early maturity boys. From 21 years and onwards they were also taller than the average-maturing boys. Thus final height differed significantly between the late-maturing boys and the other two maturity groups of boys, averaging 6" 5 cm and 4- 2 cm, respectively.
1. Introduction There are great differences in the rate of maturation between the sexes, and between individuals of the same sex. These differences in rate of maturation do not suddenly arise at adolescence, although they become more obvious then. Classification of the maturity process according to age at peak height velocity (PHV) is reliable and common in its application, and is the basis for tempo-conditional standards of growth used extensively (Tanner, Whitehouse and Takaishi 1966, Tanner and Davies 1985). It has been reported that early-maturing girls and boys on average are taller than their late-maturing peers from early childhood to about the age of 15 years in girls and 17 years in boys, but that there is no difference on average in final stature in either sex (Shuttleworth 1939, Bayley 1956, Tanner 1962, Lindgren 1978, Tanner and Davies 1985, Marshall and Tanner 1986). However, Prokopec (1982) reported that the final mean height at adult age was greater in the late maturers than in the early maturers of both sexes. Growth in standing height will on average cease at about 17-5 years in girls and 20 years in boys (Roche and Davila 1972, Taranger and H~gg 1980). The late-maturing girls will not cease growing before 21-22 years of age and late-maturing boys will not cease growing in height before 23-24 years of age (Taranger and H~gg 1980, Roche 1989). Hulanicka and Kotlarz (1983) reported, in a study of a Polish boy, that the later the age at PHV the bigger the increment in the post-adolescent period, and that the gain in height between 18 and 27 years might be quite large in some individuals. The comparisons of final stature between e~rly, average and late maturers in most of the previous studies are uncertain due to the samples, especially of boys, having not been followed during a sufficient period of time; the reference figures are usually based on an age of 18-19 years (e.g. Largo, Gasser, Prader, Stuetzle and Huber 1978, Lindgren 1978, Tanner and Davis 1985). The aim of this study was to analyse the growth pattern of height in Swedish early-, average- and late-maturing boys and girls from birth to adulthood. 0301-4460/91 $3.00 © 1991Taylor & Francis Ltd.
U. Hligg and J. Taranger
48
Materials and methods Data on growth and maturation have been collected from 212 randomly selected Swedish urban children (122 boys and 90 girls) followed from birth to adulthood as part of a prospective longitudinal and interdisciplinary study of growth and development (Karlberg, Taranger, Engstr0m, Karlberg, Landstr0m, Lichtenstein, Lindstr0m and Svennberg-Redegren 1976, H~igg 1980). The study began in 1955.
Ann Hum Biol Downloaded from informahealthcare.com by Mcgill University on 11/03/14 For personal use only.
2.
Methods o f measurement Height was measured at the following ages: 1, 3, 6, 9, 12 and 18 months, 2 years and subsequently once a year until 10 years of age, after which it was measured every third month to 18 years. The subjects were also measured at two follow-up examinations, at the age of 21 and 25 years. These were done in the same setting and by the same anthropometrists as the earlier measurements. The measurements were recorded in millimetres using the stretching-up technique (Weiner and Lourie 1969) and were generally done in the morning (Karlberg et al. 1976). From 1 month to 3 years the measurements of supine length, and from 3 years onwards the measurements of standing height, were used. Ninety per cent of the measurements in this study was performed by one of two examiners using the same equipment at all measurements of height. Methods o f analysis Growth in height. Each measurement of height was adjusted to exactly specified target age (e.g. 1 1.0, 12.0) according to a subroutine in the data processing (Karlberg et al. 1976). Increments of height were calculated using adjusted measurements taken at even ages.
Peak height velocity (PHV). The incremental curve of height was analysed graphically without any smoothing of the curve. PHV (peak height velocity) was defined by means of height measurements taken every third month (3-month mid-year PHV; Karlberg et al. 1976). Age at PHV was estimated in 80 out of 90 (88" 9°70) girls and in 103 out of 122 (84.4%) boys sampled at birth. At 18 years, 76°70 of the original sample remained in the study. At the follow-up measurements, at 21 and 25 years, 71070 and 73070 of the original sample was examined. Early and late maturers were defined on the basis of the age at 3-month mid-year PHV (Karlberg et al. 1976). PHV occurred on average at 14.0 years in boys (SD -- 1" 15 years) and at 12.0 years (SD = 0" 98 years) in girls. The age variation in the occurrence of PHV was about 6 years in each sex. According to age at PHV, the subjects were grouped as early, average and late maturers. The subjects who had PHV within a 2-year interval around the mean age, i.e. 11-13 years in girls and 13-15 years in boys, were considered to be average maturers. The distribution of the sample between early, average and late maturers in given in table 1.
Table 1. Distribution of 80 girls and 103 boys into maturity groups on the basis of their age at peak height velocity (PHV), and the age at PHV (in years). Sex
Girls Boys
Early maturers
Average maturers
Late maturers
n
Percentage
Mean
SD
n
Percentage
Mean
SD
n
Percentage
Mean
SD
17 26
21.2 25.3
10.7 12.6
0-3 0.4
51 53
63"8 51.4
12.1 14-0
0.5 0.5
12 24
15.0 23.3
13.6 15.6
0.6 0-6
Height and height velocity to age 25
49
Statistical methods. The arithmetic mean and standard deviation were calculated for each variable. To assess the statistical significance of the differences of the investigated variables between the early and late maturers, the F-test and t-test for independent samples were performed. The levels of significance used were p < 0.001, p
1991, VOL. 18, NO. 1, 4 7 - 5 6
Height and height velocity in early, average and late maturers followed to the age of 25: a prospective longitudinal study of Swedish urban children from birth to adulthood U. HAGG t
and J. TARANGER*
Ann Hum Biol Downloaded from informahealthcare.com by Mcgill University on 11/03/14 For personal use only.
tDepartment of Orthodontics, Faculty of Odontology, University of Lund, MalmO, Sweden; and Department of Children's Dentistry and Orthodontics, the Prince Philip Dental Hospital, University of Hong Kong, Hong Kong *Department of Pediatrics I, Faculty of Medicine, University of Gtiteborg, Sweden Received 11 April 1989; revised 13 July 1990
Summary. A sample of 103 Swedish boys and 80 Swedish girls followed longitudinally were grouped into early, average and late maturers on the basis of age at peak height velocity. In girls there were significant differences in height between the maturity groups from 5 to 14 years of age, but the final height did not differ between the groups. In boys there were significant differences in height between the maturity groups from 12 to 16 years, no significant difference at the age of 17 years, and from 18 years of age and on, late-maturing boys were significantly taller than the early maturity boys. From 21 years and onwards they were also taller than the average-maturing boys. Thus final height differed significantly between the late-maturing boys and the other two maturity groups of boys, averaging 6" 5 cm and 4- 2 cm, respectively.
1. Introduction There are great differences in the rate of maturation between the sexes, and between individuals of the same sex. These differences in rate of maturation do not suddenly arise at adolescence, although they become more obvious then. Classification of the maturity process according to age at peak height velocity (PHV) is reliable and common in its application, and is the basis for tempo-conditional standards of growth used extensively (Tanner, Whitehouse and Takaishi 1966, Tanner and Davies 1985). It has been reported that early-maturing girls and boys on average are taller than their late-maturing peers from early childhood to about the age of 15 years in girls and 17 years in boys, but that there is no difference on average in final stature in either sex (Shuttleworth 1939, Bayley 1956, Tanner 1962, Lindgren 1978, Tanner and Davies 1985, Marshall and Tanner 1986). However, Prokopec (1982) reported that the final mean height at adult age was greater in the late maturers than in the early maturers of both sexes. Growth in standing height will on average cease at about 17-5 years in girls and 20 years in boys (Roche and Davila 1972, Taranger and H~gg 1980). The late-maturing girls will not cease growing before 21-22 years of age and late-maturing boys will not cease growing in height before 23-24 years of age (Taranger and H~gg 1980, Roche 1989). Hulanicka and Kotlarz (1983) reported, in a study of a Polish boy, that the later the age at PHV the bigger the increment in the post-adolescent period, and that the gain in height between 18 and 27 years might be quite large in some individuals. The comparisons of final stature between e~rly, average and late maturers in most of the previous studies are uncertain due to the samples, especially of boys, having not been followed during a sufficient period of time; the reference figures are usually based on an age of 18-19 years (e.g. Largo, Gasser, Prader, Stuetzle and Huber 1978, Lindgren 1978, Tanner and Davis 1985). The aim of this study was to analyse the growth pattern of height in Swedish early-, average- and late-maturing boys and girls from birth to adulthood. 0301-4460/91 $3.00 © 1991Taylor & Francis Ltd.
U. Hligg and J. Taranger
48
Materials and methods Data on growth and maturation have been collected from 212 randomly selected Swedish urban children (122 boys and 90 girls) followed from birth to adulthood as part of a prospective longitudinal and interdisciplinary study of growth and development (Karlberg, Taranger, Engstr0m, Karlberg, Landstr0m, Lichtenstein, Lindstr0m and Svennberg-Redegren 1976, H~igg 1980). The study began in 1955.
Ann Hum Biol Downloaded from informahealthcare.com by Mcgill University on 11/03/14 For personal use only.
2.
Methods o f measurement Height was measured at the following ages: 1, 3, 6, 9, 12 and 18 months, 2 years and subsequently once a year until 10 years of age, after which it was measured every third month to 18 years. The subjects were also measured at two follow-up examinations, at the age of 21 and 25 years. These were done in the same setting and by the same anthropometrists as the earlier measurements. The measurements were recorded in millimetres using the stretching-up technique (Weiner and Lourie 1969) and were generally done in the morning (Karlberg et al. 1976). From 1 month to 3 years the measurements of supine length, and from 3 years onwards the measurements of standing height, were used. Ninety per cent of the measurements in this study was performed by one of two examiners using the same equipment at all measurements of height. Methods o f analysis Growth in height. Each measurement of height was adjusted to exactly specified target age (e.g. 1 1.0, 12.0) according to a subroutine in the data processing (Karlberg et al. 1976). Increments of height were calculated using adjusted measurements taken at even ages.
Peak height velocity (PHV). The incremental curve of height was analysed graphically without any smoothing of the curve. PHV (peak height velocity) was defined by means of height measurements taken every third month (3-month mid-year PHV; Karlberg et al. 1976). Age at PHV was estimated in 80 out of 90 (88" 9°70) girls and in 103 out of 122 (84.4%) boys sampled at birth. At 18 years, 76°70 of the original sample remained in the study. At the follow-up measurements, at 21 and 25 years, 71070 and 73070 of the original sample was examined. Early and late maturers were defined on the basis of the age at 3-month mid-year PHV (Karlberg et al. 1976). PHV occurred on average at 14.0 years in boys (SD -- 1" 15 years) and at 12.0 years (SD = 0" 98 years) in girls. The age variation in the occurrence of PHV was about 6 years in each sex. According to age at PHV, the subjects were grouped as early, average and late maturers. The subjects who had PHV within a 2-year interval around the mean age, i.e. 11-13 years in girls and 13-15 years in boys, were considered to be average maturers. The distribution of the sample between early, average and late maturers in given in table 1.
Table 1. Distribution of 80 girls and 103 boys into maturity groups on the basis of their age at peak height velocity (PHV), and the age at PHV (in years). Sex
Girls Boys
Early maturers
Average maturers
Late maturers
n
Percentage
Mean
SD
n
Percentage
Mean
SD
n
Percentage
Mean
SD
17 26
21.2 25.3
10.7 12.6
0-3 0.4
51 53
63"8 51.4
12.1 14-0
0.5 0.5
12 24
15.0 23.3
13.6 15.6
0.6 0-6
Height and height velocity to age 25
49
Statistical methods. The arithmetic mean and standard deviation were calculated for each variable. To assess the statistical significance of the differences of the investigated variables between the early and late maturers, the F-test and t-test for independent samples were performed. The levels of significance used were p < 0.001, p
