The skeletal deficiencies are intercepted and treated well when the intervention is given at the right time, which focuses mainly on the pubertal growth spurt. The goal of the present study was to evaluate whether serum DHEA-S could be used as a biomarker for assessing skeletal maturation during the pubertal growth spurt. Based on the cervical stages of Baccetti et al. [13] and cervical vertebrae maturation indicator, the samples were divided among the two groups. Thus, the relationship between serum DHEA-S levels and the CS stages could be used as a possible predictor for the assessment of pubertal growth spurt. In our study, we have taken a parallel comparator, i.e., serum IGF-1 levels, which is an established biomarker for the same purpose. Thus, the serum IGF-1 levels were measured in each stage, and its change in levels with each CS stage was compared to DHEA-S level, which would reassure the obtained results.
Among the CS stages, the highest serum DHEA-S levels were observed in the CS 3 in group B and CS 4 in group A, and the values were 578.12 ± 13.76 nmol/ml and 685.33 ± 39.11 nmol/ml respectively (Table 1). This was in contrast with the study done by Srinivasan and Premkumar [28]. In their study, subjects were divided as pre-pubertal, pubertal, and adult groups based on the hand-wrist radiographs and the sample consisted of subjects with age ranges from 7 to 30. The highest mean ± SD serum hormone level was observed in the adult group. As supported by Kroboth et al. study [24], the DHEA-S levels peak around 20–30 years of age then decreases gradually, which would be the reason for this difference in both the studies. In our study, maximum age limit taken was 21 years and grouping was focused mainly on the CS stages which are clinically related to the maxillary and mandibular growth. Though the previous study found a significant difference between pre-pubertal, pubertal, and adult groups, they were not in respect with CS stages from lateral cephalogram. The peak value observed in our study was in consistent with the first chronological peak DHEA-S values observed in the previous study [29].
Mean serum hormone levels were found to be least in the CS 6 in females and CS 1 in the males. But from the CS 1 stage, there was a significant gradual increase in the hormone levels in each CS stage until it reaches the highest value in respective groups. After reaching the peak value, there was a decrease in the serum levels. In group A, a decrease was found from CS 4 to CS 5 and to CS 6, whereas in group B, from CS 3 to CS 4, CS 4 to CS 5, and to CS 6. The peak values of serum hormones observed in the CS stages of respective groups are consistent with the pubertal growth spurts of the respective groups, i.e., CS 3 in females and CS 4 in males [13]. When accounting the sexual dimorphism, significant difference was found between the males and females in the DHEA-S levels. This could be due to the influence and interaction of difference in the sexual maturity, difference in the BMI (Table 5), and the growth pattern in the males and females than gender difference itself [30,31,32].
While observing the serum IGF-1 levels, the highest mean serum IGF-1 level was found to be in CS 4 in group A and CS 3 in group B, with values of 538.32 ± 32.31 ng/ml and 460.38 ± 13.49 ng/ml respectively, with a significant sexual dimorphism observed in each CS stage. This was consistent with the results of the previous studies [14, 18], but the values were in different ranges from the previous study which could be due to difference in the ethnicity of the subjects studied. People from different ethnicity have a different range of normal serum IGF-1 hormone levels. The change in IGF-1 values in each stage followed a typical pattern which was also found in the serum DHEA-S levels (Fig. 1 and Fig. 2). In addition, the difference between the hormone levels in each CS stage was statistically significant with a clear interval in both groups. A univariate regression analysis was done after combining the CS 1 and CS 2 as pre-pubertal, CS 3 and CS 4 as pubertal, and CS 5 and CS 6 as post-pubertal (Table 6). Compared to the pre-pubertal stage values, the pubertal stage was more likely to be predicted by both the hormones and it was statistically significant (p < 0.05) with the odds ratio that was almost same for both the hormones. Thus, it supported the use of the serum DHEA-S hormone levels to predict the different circumpubertal stages.
The serum DHEA-S levels followed a pattern similar to the pubertal growth curve and to the serum IGF-1 level. The peak in the graph was consistent with the pubertal-skeletal growth accelerations. In addition, the regression analysis revealed the possible association with the different stages. But the only difference was the comparable difference found in the serum DHEA-S levels between the CS 5 and CS 6 in group B which may reduce the use of DHEA-S levels to assess the CS 5 and CS 6 stages. Otherwise, the findings support the definitive relationship between the serum DHEA-S levels and the CS stages. Hence, this relationship between the serum DHEA-S and the CS stages among the circumpubertal age rejected the null hypothesis. The preliminary work done with a relatively small sample size in a cross-sectional study design could be a possible set back of our study, which needs further prospective analysis in a larger population.