Height, growth velocity, weight and body mass index (BMI) are biomarkers of child health and society's wellbeing.1–3 After birth, growth velocity declines progressively until pubertal growth spurt onset (PGSO) which occurs over a five-year period in both sexes (girls: 8–13 years of age, boys: 10–15 years of age).4,5

Longitudinal growth studies clearly define age at PGSO. However, due to the low number of children included, they tend to present data on pubertal growth as for a single group, without taking into account the different pubertal maturity tempo of each child.6,7 Errors made when a single pubertal reference group is used to evaluate pubertal growth show up in clinical practice; consequently, the need for more than one pubertal reference group has been proposed.4,5,8–10

Our previous longitudinal growth study (1978–2000) presented pubertal growth data of 259 girls and 281 boys allocated to one of five 1-year-age-interval pubertal maturity groups (very-early, early, intermediate, late and very-late) according to their age at PGSO.5 Owing to the low number of children in each group, we started in 1995 a new longitudinal study aimed at recruiting a minimum of 100 healthy non-obese children in each of the five groups for each sex, to confirm or deny clinical significant differences in the pubertal growth pattern among the five pubertal maturity groups.

The study group comprised 1,908 healthy children of the middle-to-upper socioeconomic district of Barcelona. Children with chronic diseases, chronic drug therapies or BMI values<−2.0 SDS (age- and sex-matched controls11) were not included. Over the study period (January 1995 to March 2017), 132 children were ruled out for obesity (physical examination and BMI>2.0 SDS of age- and sex-matched controls11) and 323 were lost. Thus, 1,453 (743 girls, 710 boys) who reached adult height between January 2012 and March 2017 completed the study and data from their height and weight measurements (girls 6–18 years of age, boys 6–19 years of age) were analyzed. Population A (239 girls, 238 boys) was followed at four pediatric practices and population B (504 girls; 472 boys) at four schools. In population A, all were born at term with appropriate weight and length12; these data were not collected for population B.

Height and weight were recorded every 6–12 months by four researchers in population A and once a year by one of the four in population B. Height was measured with rigid wall-mounted stadiometers in population A and with the same portable rigid stadiometer in population B. Stadiometers were calibrated similarly throughout the study. Weight was recorded with digital floor scales (population A in underwear; population B in T-shirt and skirt/trousers, the estimated weight of the T-shirt and skirt/trousers was subtracted from the overall weight). Measurements were taken to the nearest 0.1centimeter (cm) for height and 0.1kilogram (kg) for weight. Tanner's pubertal stages and testicular volume were recorded every six months in population A but not in B for ethical reasons. Age at menarche was recorded in both populations.

The anthropometric growth program “Auxolog” based on data from our previous longitudinal growth study5,13 was used to construct height-for-age, growth-velocity-for-age and weight-for-age growth charts for each child. PGSO was evaluated by Tanner's criteria6,7 and according to age at PGSO5 children were considered very-early (girls 8–9 years, boys 10–11 years), early (girls 9–10 years, boys 11–12 years), intermediate (girls 10–11years, boys 12–13 years), late (girls 11–12 years, boys 13–14 years) and very-late (girls 12–13 years, boys 14–15 years) matures (Fig. 1). Mean values for height for age (cm), growth velocity for age (cm/year), weight for age (kg), adult height (growth velocity <1cm/year in two consecutive 6–12-month intervals), pubertal height gain (cm) (PGSO to adult height), age at menarche (years) and growth (cm) from menarche to adult height were calculated for each of the five pubertal maturity groups and for the whole population (Tables 1–3).

Figure 1.

Mean height-for-age and growth velocity-for-age values for the five pubertal maturity groups. Statistically-significant (p<0.0001) and clinically-pertinent differences were found among them according to age at pubertal growth spurt onset.

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Among the 743 girls, age at PGSO was between 8–9 years in 119, 9–10 years in 157, 10–11 years in 238, 11–12 years in 127 and 12–13 years in 102, and girls were considered very-early, early, intermediate, late and very-late matures, respectively. Among the 710 boys, age at PGSO was between 10–11 years in 110, 11–12 years in 139, 12–13 years in 225, 13–14 years in 133 and 14–15 years in 103, and boys were considered very-early, early, intermediate, late and very-late matures, respectively (Tables 1–3).

For both sexes, in each of the five pubertal maturity groups and in the whole population, mean values for any anthropometric variable at any age (6 years to adult height) were similar and did not differ statistically between populations A and B. Thus, for each sex, joint data of both populations were analyzed as a single population.

Longitudinal growth studies provide reference values for pubertal growth evaluation. As pubertal growth differs depending on age at PGSO the need for more than one pubertal reference has been proposed.4,5,8–10

Herein, we report from 6 years of age to adult height, height-for-age, growth velocity-for-age, and weight-for-age values of 1453 healthy non-obese children of the middle-to-upper socioeconomic district of Barcelona, in whom the anthropometric measurements were taken by only four researchers using similarly adjusted equipment. The study was designed with the aim to reduce the anthropometric values dispersion observed in growth studies owing to the heterogeneity of the populations studied, the number of researchers involved and the equipment used. Children were allocated to one of the five 1-year-age-interval pubertal maturity groups (very-early, early, intermediate, late and very-late) according to their age at PGSO.

In each sex, mean birth length (population A, data not shown), mean birth weight (population A, data not shown), mean adult height, and mean adult weight values were similar among the five pubertal maturity groups. However, mean height-for-age, mean growth velocity-for-age and mean weight-for-age values differed from 6 years of age onwards. Differences were discrete and of poor clinical significance when all girls (age<8 years) and all boys (age<10 years) were prepubertal. However, they did increase and became clinically pertinent from this age onwards, according to PGSO, disappearing at adult height age.

In both sexes, PGSO is a critical milestone determining growth rate (height and weight gains) of puberty, Tanner's stage development and, in girls, age at menarche and growth from menarche to adult height. Each pubertal maturity group has its own pubertal development pattern, which also differs from those of the whole population. In clinical practice, individual pubertal growth (height, growth velocity and weight) and sexual development evaluation with their corresponding pubertal maturity group pattern (very-early, early, intermediate, late, and very-late) may help to avoid the errors currently made when only the pubertal maturity group of the whole population is used.

Although a bias in our results can completely not be rule out, in both sexes, prepubertal height-for age (girls age<8 years, boys age<10 years) and adult height values were similar to those reported in recent Spanish,11 European14–20 (except for Dutch population which was 5.9cm taller for both sexes at adult height) and American21,22 cross-sectional studies, which suggests that our data of the five pubertal maturity groups may also be useful for evaluating pubertal growth in these populations.

In girls, BMI values were not statistically different among the five pubertal maturity groups at PGSO, and at the age of menarche. The same occurred in boys at PGSO, except for values between very-late group and very-early, early and intermediate groups, although these differences were of poor clinical significance. These data suggest that a similar body mass is necessary to start puberty in both sexes and in girls, to have menarche, regardless of the age at what they occurred. Moreover, age at menarche for the whole population was similar to those reported recently by others, which concur with the secular acceleration observed in recent years.23–25

In summary, anthropometric data (height, growth velocity, and weight, all for age) during pubertal growth were obtained for both sexes from a longitudinal growth study including 1453 healthy non-obese millennial children classified in five different pubertal maturity groups according to age at PGSO. These data might contribute to better clinical evaluation of growth according to the pubertal maturity tempo of each child and to avoidance the mistakes currently made when only one pubertal reference group are used. Data on sexual development and, in girls, age at menarche are also reported.

Charts for height, growth velocity, weight and BMI, all for age, calculated by the LMS method will be available (centiles and SDS values) and downloaded free of charge from the web site: http://www.millennialsgrowth.com (available February 2018) (Cole TJ. The LMS method for constructing normalized growth standards. Eur J Clin Nutr 1990;44:45–60).

The authors declare no conflict of interest.