The results from this study have shown slight to moderate positive correlations between height with DBP and SBP categories of normotensive and hypertensive BP. These correlations were relatively similar in the height ranges determined by 5 and 10 cm. However, when comparing DBP and SBP by height range of 5 cm by sex, significant differences occurred in 4 height ranges (from 128 to 133 cm; 133 to 138 cm; 138 to 143cm; and from 143 to 148 cm). In addition, significant differences were observed in the 10 cm range in only one range of 138 to 148 cm in DBP and in SBP, height from 158 to 168 cm
As a result, based on the findings obtained, the results from this research demonstrated that the BP differs very little in the height ranges of 10 cm. This appears to reflect a better suitability to evaluate DBP and SBP in children and adolescents in the Maule region in relation to 5 cm.
In fact, in the 10 cm ranges, children and adolescents from various ages were grouped together to fit into particular height ranges. This allowed correcting for slow and/or rapid growth rates among children and adolescents. This is to say that at whatever age height may vary, resulting to a large extent in the presence of a wider range of BP [12] values. Therefore, the use of 10 cm height intervals to evaluate BP may be an advantage over chronological age since it is widely known that during the stages of childhood and adolescence that children and adolescents experience important changes in maturation during physical growth [20].
In this sense, height is a practical and accurate measure that serves to evaluate a variety of populations and diverse ethnic groups during the growth stage, especially when it is used in conjunction with evaluating BP [12,21,22]. Furthermore, it appears to be immanent that efforts are being made to correct and create simpler and more practical techniques and tools to better identify hypertension in children [23] and adolescents and incorporate height routinely into medical examinations.
A number of studies have reported that height is a non-invasive alternative that serves to analyze changes and/or thresholds of BP related to chronological age [24]. Also, height is considered as a useful indicator for doctors. The use of this anthropometric variable may contribute to identifying children and adolescents with elevated BP and, consequently, offer a possible treatment [8].
In fact, based on previous findings, the researchers developed percentiles for DBP and SBP based on 10 cm height ranges for children and adolescents of the Maule region. In effect, the United States Department of Health and Human Services [17] maintains that the reference values for BP thresholds for children and adolescents need to meet the requisites for six variables: DBP, SBP, age, gender, eight, and percentile for height.
The proposed percentiles for this study meet the requirements indicated above. This tool may serve as a simple and easy to use alternative for early detection of pre- and hypertension in children and adolescents. It may also be useful for professionals working in clinical and epidemiological contexts. It may also have an important role in the prevention of cardiac [25] diseases during growth and development.
As a result, the cut-off points adopted for this research were those proposed in the fourth report of the US Department of Health and Human Services [17]: <p90 as normotensive; ≥p90 to p95 as pre-hypertensive; and ≥p95 as hypertensive.
These cut-off points determine limits and identify children and adolescents at greater risk of pediatric hypertension. The cut-off points also help identify individuals who need to have more examinations to control BP, including promoting preventative and healthy [2] lifestyles.
It is widely recognized that the reference standards for development for a specific population may not be applicable to other geographic regions. This is due to racial, ethnic, anthropometric, and cultural [26] differences.
In this sense, in a recent study carried out by other researchers [27], they determined that the students from the Maule region reached adult height of 172.1±6.9 cm for males and 159.8±5.7 cm for females. In fact, these values correspond to a height range of the percentiles proposed here of 168-178 cm for males with a BP of 139.9/86.6mmHg and for females, a height range of 158-168 cm with a corresponding BP of 130.4/84.8mmHg. These values at 18 years old are close to the limits of 140/90mmHg used for adults, coinciding with the values obtained in the present study.
Future studies need to evaluate not only height ranges, but also they need to explore ranges for weight, BMI, waist circumference, and among other anthropometric variables. Furthermore, it is necessary to develop longitudinal studies since height growth varies ostensibly, especially during the transition from childhood to adolescence.
As a result, despite the limitations highlighted here, this research has some strengths. For example, the probability selection of the sample makes it possible to generalize the results to other contexts with similar characteristics. Moreover, the proposal of an on-line electronic calculator system greatly facilitates the evaluation of BP by height and by chronological age. The printed letters may be obtained manually by using the following link: http://www.reidebihu.net/pad_pas_ch.php