Relationship between Sitting Height Measurements and Standing Height: A Prospective Regional Study among Adolescents in the Northern Region of Kosovo

The purpose of this research is to determine a regression equation for the estimation of stature from sitting height measurements in the northern region of Kosovo. This research was carried out on 177 individuals (87 male and 90 female). The anthropometric measurements were taken according to the ISAK protocol. The relationships between standing height and sitting height measurements were determined using simple correlation coefficients at a ninety-five per cent confidence interval. A comparison of the means of standing height and sitting height between genders was performed using a t-test, following which a linear regression analysis was carried out to examine the extent to which sitting height can reliably predict standing height. The results reveal that northern Kosovan males are 180.29±5.72 cm tall and have a sitting height of 95.64±3.93 cm, while northern Kosovan females are 165.36±4.56 cm tall and have a sitting height of 90.19±3.03 cm. The results indicate that both genders made northern Kosovans a tall group, slightly taller than the general male and a slightly shorter than the general female Kosovan population. Moreover, the sitting height reliably predicts standing height in both genders, but not as reliably as arm span. This study also confirms the necessity for developing separate height models for each region in Kosovo as the results from northern Kosovans do not correspond to the values of the general Kosovan population.


ch region in
osovo as the results from Eastern-Kosovans don't correspond to the general values.

Introduction

According to Komunat e Kosovës (2013), Kosovo is a demo cratic, multi-ethnic and secular republic which administrati vely is subdivided into seven districts (Ferizaj, Gjakova, Gjilan, Mitrovica, Peja, Pristina and Prizren) and fi ve regions (Eastern, Western, Northern, Southern and Central).This study analyzes the standing height and its estimation utilizing sitting height measurements in adolescents in eastern region which contains two districts (Ferizajand Gjilan) and eleven municipalities (Ferizaj, Hani iElezit, Kaçanik, Štimlje/Shtime, Štrpce/Shtërpcë, Gjilan, Kamenica, Klokot, Partesh, Ranilug and Vitina).This region (Figure 1) covers the area of 2,236 square kilometers and has population of 366,589 inhabitants, while average density per square kilometer is 255 inhabitants (Komunat e Kosovës, 2013).Although Kosovo doesn't have too big territory, it has a very varied relief that mostly belongs to Dinarides range and the author assumed this fact might infl uence the main objective of this study, because of the type of the soil as well as other socio-economical and geographical characteristics as a potentia infl uencing factors (Arifi , 2017;Arifi , Sermaxhaj, Zejnullahu-Raçi, Alaj, &Metaj, 2017b).

There are lots of scientifi c fi ndings which confi rms that the measurement of standing height is a vitally important variable when assessing nutritional status (cited in Arifi et al., 2017a;Datta'Banik, 2011;Popovic, & Bjelica, 2016), as well as when assessing the growth of children, evaluating the basic energy requirements, adjusting the measures of physical capacity and predicting the drug dosage and setting standards of physiologi-cal variables such as muscle strength, metabolic rate, lung volumes and glomerular fi ltration (Golshan, Amra, & Hoghogi, 2003; M. Golshan, Crapo, Amra, Jensen, & R. Golshan, 2007;Mohanty, Babu, & Nair, 2001;Ter Goon, Toriola, Musa, & Akusu, 2011).However, according to Quanjer and his collaborators (2014), the exact standing height cannot always be identifi ed and resolved in the usual way (e.g.paralysis, fractures, amputation, scoliosis and pain).Because of these factors, an estimate of standing height has to be acquired from other reliable anthropometric indicators such as sitting height, hand and foot lengths, knee height, length of the forearm, length of the sternum, vertebral column length, length of scapula, arm span as well as cranial sutures, skull, facial measurements et cetera (cited in Gardasevic, Rasidagic, Krivokapic, Corluka, & Bjelica, 2017;Popovic, 2017;Masanovic, 2017;Masanovic, Gardasevic, & Arifi , 2018a;Masanovic, Gardasevic, & Arifi , 2018b).Therefore, all these anthropometric indicators, which are used as an alternative to estimate standing height, are very important in predicting loss in standing height connected with aging.Also, to diagnose individuals with disproportionate growth abnormalities and skeletal dysplasia or standing height loss during surgical procedures on the spine (Mohanty et al., 2001), as well as to anticipate standing height in many older people as it is very diffi cult to measure it precisely, and sometimes impossible because of mobility problems and kyphosis (Hickson, & Frost, 2003).Lastly, it is important to state that this knowledge fi nds its importance in sport science the standing height represents a signifi cant factor which infl uences the success in various sport discip ines (Popovic, 2017).

Several researches have reported the benefi t of using various body parameters in predicting standing height, and arm span happened to be one of the most reliable ones in adults (Hickson, & Frost, 2003;Jalzem, & Gledhill, 1993;Mohanty et al., 2001;Ter Goon et al., 2011), while foot length measurement is the most reliable predictor during adolescent age, due to the fact that ossifi cation and maturation occurs earlier in the foot than the long bones and standing height could be more accurately predicted from foot measurement as compared to long bones during adolescent age (cited in Singh, Kumar, Chavali, & Harish, 2012).In addition, the relationship of long bones and standing height was found to vary in different ethnic and racial groups (Bjelica, Popovic, Kezunovic, Petkovic, Jurak, & Grasgruber, 2012;Brown, Feng, & Knapp, 2002;Popovic, Bjelica, Georgiev, Krivokapic, & Milasinovic, 2016;Popovic, Bjelica, Molnar, Jaksic, & Akpinar, 2013;Popovic, Bjelica, Tanase, & Milasinovic, 2015;Reeves, Varakamin, & Henry, 1996;Steele, & Chenier, 1990) as well as various regions (Arifi , 2017;Arifi et al., 2017b;Milasinovic, Popovic, Matic, Gardasevic, & Bjelica, 2016;Milasinovic, Popovic, Jaksic, Vasiljevic, & Bjelica, 2016;Masanovic, Gardasevic, & Arifi , 2018c;Masanovic, Gardasevic, & Arifi , 2018d).Hence, researchers have derived a specifi c formula for calculating standing height from long bones for each ethnic/race group.The mentioned variations might be the case with sitting height predictions too, mostly due to the fact that the Dinaric Alps population has specifi c body composition than national as well as regional point of view (Popovic, 2017).Even though many studies with this essence are available on neighboring countries as well as worldwide population, only narrow data is available on Kosovan subjects, just one conducted by Popovic and his collaborators (Popovic, Arifi , & Bjelica, 2017a;Popovic, & Bjelica, 2017) that has covered whole Kosovan population, and one regional analyses that confi rmed Western-Kosovans have specifi c standing height/sitting height ratio, comparing to general population in Kosovo (Popovic, Gardasevic, Masanovic, Arifi , & Bjelica, 2017).Considering rather sparse recent scientifi c literature, the purpose of this research was to examine the standing height in both Eastern-Kosovan genders

nd its a
sociation with sitting height.


Methods

The nature of this research gave extension to the 364 highschool students last year (185 male and 179 female) from Eastern Region of Kosovo to be subjects.Two reasons which qualifi ed the selected individuals are: the fi rst is related to the fact that the growth of an individual ceases by this age, while the second is related to the fact that there is no age-related loss in standing height at this age.The average age of the male subject was 18.20±0.40years old (range 18-19 years), while the average age of the female subject was 18.15±0.36years old (range 18-19 years).It is important to underline that the researchers have excluded from the data analysis of the individuals with physical deformities as well as those without informed consent.The exclusion criterion as also being non-Eastern Kosovan.

The anthropometric measurements, including standing height and sitting height, were taken according to the protocol of the International Society for the Advancement of Kinanthropometry (Marfell-Jones, Olds, Stew, & Carter, 2006).The trained measurers have measured selected anthropometric indicators (same measurer for each indicator), while the quality of their performance was evaluated against the prescribed "ISAK Manual".Lastly, the age of the each subject was rea hed directly from the birthdays.

The analysis were performed by using the Statistical Package for Social Sciences (SPSS) version 20.0.Means and standard deviations (SD) were obtained for both anthropometric variables.A comparison of means of standing height and sitting height between genders was performed using a t-test.The relationships between standing height and sitting height were determined using simple correlation coeffi cients at ninety-fi ve percent confi dence interval.Then a linear regression


Results

A summary of the anthropometric measurements in both genders is shown in Table 1.The mean of the standing height for male was 178.79±6.07centimeters and sitting height was 96.07±3.51centimeters, while for female the standing height was 164.60±4.72 centimeters and sitting height was 90.70±2.92centimeters.The sex difference between standing height and sitting heighmeasurements was statistically significant (standing height: t=24.849;p<.000, and sitting height: t=16.180;p<.000).

In Table 2, the simple correlation coeffi cients an

ty-fi ve percent confi dence interval analysis between the anthropometric
measurements are displayed.The associations between standing height and sitting height were signifi cant (p<0.000) and high in this sample, regardless of gender (male: 0.743; female: 0.705).

The results of the linear regression analysis are shown in Table 3.The fi rst of all models were extracted by including age as a covariat .However, it was found that the contribution of age was insignifi cant and therefore the age was dropped and estimations were derived as a univariate analysis.The high values of the regression coeffi cient (male: 0.743 female: 0.705) signify sitting height notably predicts standing height in both Eastern-Kosovan genders (male: t=15.027,p<0.000; female: t=13.214,p<0.000), which confi rms the R-square (%) for the male (55.2) as well as for the female (49.7).

The associations between sitting height measurements and standing height among the above models is sketched as a scat-ter diagrams (Figure 2).
Discussion

The assessment of standing height using various anthropometric measures is very typical from the past centuries and it has been at

mpted to be
studied by many researchers.However, it is important to underline that the arm span has been obtained as the most reliable body indicator for predicting the standing height of an individual (Mohanty et al., 2001;Ter Goon et al., 2011), while sitting heightis was very close (Arriba Munoz et al., 2014).In parallel, it is important to emphasize that the individual and ethnic variations referring to standing height and its association with sit ting heightmight vary from ethnic group to ethnic group as well as race to race, because the racial and ethnic differences are affective on these measures and reduce the possibility of generalizing (cited in Bjelica et al., 2012).This fact confi rms the study conducted by authors (Frederiks et al., 2005;Arriba Munoz et al., 2014) who confi rmed a very high linear correlation between standing height and sitting height in both genders, while the research study conducted by Fatmah and her collaborators (2010) shows signifi cant correlation between standing height and sitting height in both genders of Indonesian population.The highest correlation coeffi cient in this population was found for sitting heightin males (r=0.743) as well as in females (r=0.705).

All above-mentioned have confi rmed the necessity for developing separate standing height models for each population on account of ethnic differenc s and the recent study conducted by Popovic and his collaborators (Popovic et al., 2017a;Popovic, & Bjelica, 2017) who have analyzed the entire Kosovan population and have found specifi c correlation coeffi cient in Kosovan male (r=0.691) and female (r=0.629)population; however, some recent studies have also confi rmed the regional differences between the same ethnic groups too (Arifi , 2017;Arifi et al., 2017b;Popovic et al., 2017b;Milasinovic et al., 2016a;2016b), which caused the need for additional caution, mostly due to the reason one of them was sampled by Western-Kosovans.Therefore, the main goal of this research was to test the hypothesis if above-mentioned facts are true for the Eastern-Kosovans, that is, for the one of fi ve Kosovan regions.Hence, in the present research it was remarked that the sitting height/standing height ratio in Eastern-Kosovan male is bigger (male: 55.2%; female: 49.7%) comparing to entire Kosovan (male: 47.7%; female: 39.6%) and Western-Kosovans (male: 43.7%; female: 37.7%)as well as smaller comparing to other available population that estimate over 70% each and more in male population, while female population is much more in parallel to previously measured populations.As the correlation between sitting heightand standing height was signifi cant in both Eastern-Kosovan genders, the sitting heightmeasure therefore seems to be a reliable indirect anthropometric indicator for estimating standing height in both genders of Eastern-Kosovan population.Even though these relations are similar, the estimation equations, which are obtained in the Eastern-Kosovans, considerably differ from entire Kosovan, Western-Kosovans and other available populations.

The results of the study conducted by Popovic and his collaborators (Popovic et al., 2017a;Popovic, & Bjelica, 2017) confi rm t e necessity for developing separate standing height models for both genders in Kosovo but the authors of the same study have recommended that further studies should consider dividing the population of this country to regional subsam-ples and analyze it separately, just to be sure there are no geographical differences (such as type of the soil) infl uencing the average standing height in both Kosovan genders as well as its association with sitting height.This concern was based on the fact that entire Kosovo doesn't fall into Dinaric Alps racial classifi cation.In parallel, this study confi rms the assumption mentioned above and also confi rms that it is necessary to develop separate standing height models for each population on account of regional variations in Kosovo.

Next to highlighted issue, the obvious constraint of this research might also be the composition of the easured sample that consisted of high school students.This limitation is based on the fact there are some studies which assumed the growth of an individual doesn't cease by this age (Grasgruber, P., personal communication, 2016;Jurak, G., personal communication, 2017).This assumption might be supported by the fact that university-educated individuals have been founded to be taller than the high school population in Bosnia and Herzegovina (Grasgruber et al., 2017;Gardasevic et al., 2017), Poland (Wronka, &Pawlinska-Chmara, 2009) and Hungary (Szollosi, 1998).On the other hand, this wasn't the truth in Montenegro (Popovic, 2017) and comparing the average standing height measures of this study to the results of some study sampled by university students might give the science much precise conclusions.One more obvious limitation of this study is also the fact that both genders of Kosovo did not reach their full genetic potential yet, since various environmental factors controlled their development.Further continuous monitoring is necessary, mostly due to the reason it is expected the secular changes infl uencing standing height will ascend in the following two or three decades.

Figure 1 .
1
Figure 1.Geographical Location of Eastern Region in Kosovo







Table 1 .
1
Anthropometric Mea