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Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan
Egyptian Pediatric Association Gazette xxx (2017) xxx–xxx
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Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan Gihan Yousef Ali a,b,⇑, Essam Eldin Abdelbary c,d, Waleed Hamad Albuali a, Nagah Mohamed AboelFetoh b, Eglal Hussein AlGohary a a
Pediatric Department, College of Medicine, KFU, Alhasa, Mail box: 400, Saudi Arabia Sohag College of Medicine, Sohag University, Egypt c Radiology Department, Sohag College of Medicine, Sohag University, Egypt d King Feisal University, College of Medicine, Surgery Department, Alhasa, Mail box: 400, Saudi Arabia b
a r t i c l e
i n f o
Article history: Received 29 November 2016 Accepted 20 March 2017 Available online xxxx Keywords: Bone mineral density Bone mineral contents Dexa scan Children Saudi Arabia
a b s t r a c t Objectives: Optimization of bone health is a very important concern now a day. Achievement of optimal peak bone mineral mass is the best means of preventing osteoporosis in adulthood. Dual-energy X-ray absorptiometry (DXA) has become the basis for the evaluation of skeletal health in all ages. The aim of the work: This work aims to assess bone parameters in Alhasa children, Saudi Arabia. Patient & methods: A Cross-sectional survey study involves 126 healthy children (83) boys & (43) girls. Their ages range from (3–15 years). Results: The mean of Bone mineral density (BMD) and bone mineral content (BMC) were (0.915 ± 0.34 & 0.795 ± 0.133) (43.93 ± 29.4 & 37.63 ± 11.2) in boys and in girls respectively. These values were lower than other areas in Saudi Arabia. BMD & BMC are statistically significant positive correlation with age in both sex, (r = 0.567 P = 0.000 & r = 0.57 P < 0.001) and (r = 0.831, P = 0.000 & r = 0.818 P < 0.001) respectively. Level of BMD & BMC acquisition were more in boys than girls in all age groups especially group (12–15 years). The mean Z score shows significant steady decrease with age in both sexes. Height, Weight, BMI, showed significant positive correlations with changes in BMD & BMC. While Calcium level and Vitamin D level showed negative correlations. Conclusion: The average BMD & BMC in Saudi children is less than that of other races. It shows no significant difference with other Saudi population. Height, weight, BMI Calcium level and Vitamin D level can predict the changes in the BMC & BMD. Ó 2017 The Egyptian Pediatric Association. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Introduction Bone is a highly ‘‘dynamic” and specialized connective tissue; its main function is to provide a mechanical support & mineral homeostasis to the human body.1 Over the last decade, the bone health monitoring is increasingly important, especially in the pediatric population.2
Peer review under responsibility of Egyptian Pediatric Association Gazette. ⇑ Corresponding author at: Pediatric Department, College of Medicine, KFU, Alhasa, Mail box: 400, Saudi Arabia, Pediatric Department, Sohag College of Medicine, Sohag University, Egypt. E-mail addresses: [email protected], [email protected], jyousef@kfu. edu.sa (G.Y. Ali), [email protected] (E.E. Abdelbary), [email protected] (W.H. Albuali), [email protected] (N.M. AboelFetoh), dreglalhs@gmail. com (E.H. AlGohary).
Bone mass shows a progressive increase from the birth, until the third decade of life, when it reaches a maximum value defined ‘‘peak bone mass.3 Peak bone mineral accrual occurs during early puberty while peak bone mass is achieved in young adulthood.4 Achievement of optimal peak bone mineral mass is the best means of preventing osteoporosis in adulthood.5 The accrual of Bone Mineral Density (BMD) during growth has therefore arise interest; there is an ongoing debate on whether a low BMD in childhood predicts a low BMD in adulthood.6 As bone properties change rapidly during growth, making a prediction on adult BMD from childhood measurements is difficult. Serial measurements cover both the pre-pubertal and postpubertal phases is important for accurate predictions.7 Several factors influence the mineralization of bones in childhood and adolescence, including genetic factors, sex, nutrition, endocrine factors, and mechanical factors.8
http://dx.doi.org/10.1016/j.epag.2017.03.005 1110-6638/Ó 2017 The Egyptian Pediatric Association. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
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G.Y. Ali et al. / Egyptian Pediatric Association Gazette xxx (2017) xxx–xxx
Low bone mineral density is the primary cause of compromised bone health. Many factors can contribute to low bone mineral density. Unfortunately, in Saudi Arabia genetic background, customs, diet, and geographical location is identified as predisposing factors for osteoporosis.9 In children Low bone mass is usually suspected after X-rays demonstrate osteopenia, after a low-trauma fracture, or when a child has a known disorder associated with low bone mass. Nowadays, the widest method to assess BMD& Bone mineral contents (BMC) is Dual-energy X-ray absorptiometry (DXA). It becomes the basis for the evaluation of skeletal health in all ages. It assesses BMD, BMC, and body composition.10 The International Society for Clinical Densitometry recommends a skeletal status evaluation in children and adolescents based on age-, sex-, and ethnicity-specific normative Ref. [11] DXA scan is now considered the standard reference for defining the rate of mineralization in the total skeleton in different regions. The dose of the DXA radiation is extremely low (5–10 u Sv). It generally takes 5–10 min to be performed, rarely needs sedation and low cost.8 DXA scan can identify bone-density losses of as little as 3%.12 It is by far, the most widely used unique technique for measuring BMD in children .11 The interpretation of DXA values in children is much more difficult than in adults because the skeleton is continuously changing and there is no precise point of reference. It has some limitations, especially in children. Bone size varies less in adults than in growing children. Particularly during the rapid growth phase of puberty, thus age and puberty maturation are important considerations.3,13 Most bone Densitometers in children report BMD as a Z score, related to an age-matched (and sometimes gender or ethnic group matched population.14 This study is designed to screen for BMD and BMC in Saudi children. To detect their relation with anthropometric measure. Study factor affecting their changes especially the serum Calcium, Vitamin D level. Patients & methods This cross-sectional study performed in King Feisal university polyclinic, in a period from 2012–2014, 126 patients were included in this study. They were 82 (65.9%) males and 44 (34.1%) females. Inclusion criteria Age more than 3 years of age, and apparently healthy children. Exclusion criteria Children whom Parents refuse to scan and Children with any chronic illness.
Dean of scientific affairs & Ethical comities in the university and polyclinic approved the study Parent’s verbal consent to perform DEXA scan to their children was also obtained. Complete history with special inquire about age, sex, history of previous fracture, blood transfusion, lifestyle and receiving drugs was obtained. Complete examination with comment in the weight, height, and any manifestation of chronic illness was done. A Blood sample was taken for estimation of serum calcium, and active Vitamin D level. DXA scan was using (GE Excel DXA – compact pencil beam axial scanner) present in the polyclinic, BMC measured in grams bone area (BA), and BMD (in gram/square centimeter) from the lumbar spine (LS) (L1–L4). The position size and location of the region were the same for all children. The machine that is adjusted to specific age- and sex- reference data calculates Zscores automatically. The scan was analyzed and diagnosed by an experienced consultant of radiology, with more than 20 years’ experience. Statistical analysis Results were analyzed using SPSS program version 21 for Windows. Statistical descriptive data were reported as mean ± SD. Association of variables was tested with Pearson or Spearman correlation. Simple regression analysis was first performed to screen potential predictors for BMD & BMC and a multivariate stepwise linear regression model was used to identify and determine significant predictors for bone mass. A P-value of less than 0.05 was considered statistically significant. Results This study include 126 healthy children, they were 65.1% (n: 82) males and 34.9% (n: 44) females. Their anthropometric parameters are shown in the Table 1. The children grouped according to gender and age into 4 groups. The mean ±SD of BMC & BMD in the studied group are demonstrated in Table 2. A comparison between Bone parameters in our cases and other areas in Saudi Arabia shows that our cases have BMD&BMC means less than other in Jeddah study done by Al-Ghamdi et al. 2012,15 these difference is not significant in BMC while there is a significant difference in their BMD in all age groups. The estimated BMD in both boys & girls Table 3. BMD changes shows significant positive correlation with age in both sexes, (boys r = 0.57 P > 0.001) (girls r = 0.818 P > 0.001). Maximum annual increase in BMD in boys was in age (13–15 yrs.), it was 52.7%
Table 1 Anthropometric parameters for study groups. Age Groups
1 (3–5) 2 (6–8) 3(9–11) 4 (12–15)
Numbers (%)
Height (cm)
BMI (kg/m2)
Weight (kg)
Mean + SD
C V%
Mean + SD
C V%
Mean + SD
C V%
Boys 82 (65.1)
Girls 33 (34.9)
Boys (119.2 ± 15.73)
Girls (127.4 ± 20.3)
Boys
Girls
Boys (22.3 ± 10.1)
Girls (26.6 ± 10.8)
Boys
Girls
Boys (14.9 ± 2.4)
Girls (15.4 ± 2.2)
Boys
Girls
33 (40.2) 27 (32.9) 19 (23.2) 3 (3.7)
13 (29.5) 14 (31.8) 7 (15.9) 10 (22.7)
108.1 ± 7.1
107.15 ± 4
6.6
4.3
17.25 ± 2.5
17.6 ± 0.7
14.3
10.0
14.40 ± 1.4
14.77 ± 1.2
9.3
8.9
118.2 ± 9
121.3 ± 11.7
7.7
9.7
20.55 ± 3.8
23.15 ± 9.0
16.8
25.9
14.46 ± 1.3
14.6 ± 1.2
7.3
16.8
132.8 ± 10.88
134.3 ± 7.9
10.4
6.4
26.7 ± 4.8
28.2 ± 3.8
23.3
15.0
14.86 ± 2.23
15.68 ± .9
13.3
5.6
164.66 ± 12.7
157.4 ± 4.9
10.4
3.3
66.33 ± 9.8
41.9 ± 5.3
21.9
13.0
24.07 ± .0.46
16.8 ± 2.3
2.4
13.4
Coefficient of Variation %.
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
Age groups
Mean ± SD of BMC (gm) Boys
Group 1 (3–5) Group2 (6–8) Group 3 (9–11) Group4 (12–15)
Mean ± SD of BMD (gm/cm2) Boys
P value
Ahasa
Jeddah
No.33 13.15 ± 3.02 No.27 15.58 ± 7.7 No.19 20.19 ± 3.6 No.3 43.94 ± 29.45
NO. 42 19.3 ± 6.4 No.59 25.5 ± 6.8 No.30 28 ± 8.2 No.19 37.7 ± 6.4
0.999 0.201 0.999 0.624
Ahasa
Jeddah
No. 33 0.46 ± 0.076 NO. 27 0.51 ± 0.11 No. 19 0.56 ± 0.07 No. 3 0.92 ± 0.34
No. 42 0.74 ± 0.12 No. 59 0.82 ± 0.1 No. 30 0.84 ± 0.14 No. 19 0.95 ± 0.06
P value
Mean ± SD of BMC (gm) Girls Ahasa
Jeddah
0.000*
NO: 3 13.18 ± 1.1 No.14 13.86 ± 4.7 No.7 18.1 ± 1.04 No.10 37.63 ± 11.2
No.40 16.8 ± 5.5 No. 57 29.3 ± 9.8 No. 42 30.4 ± 8.8 No.11 35.4 ± 12.9
0.000* 0.000* 0.88
P value
Mean ± SD of BMD (gm/cm2) Girls Ahasa
Jeddah
1
N0. 13 0.47 ± .02 No. 14 0.47 ± 0.08 No. 7 0.54 ± 0.03 No.10 0.79 ± 0.13
N0. 40 0.73 ± 0.09 No. 57 0.92 ± 0.19 No. 42 0.94 ± 0.17 No.11 1.04 ± 0.19
0.999 1 0.574
P value
0.000* 0.000* 0.000* 0.002*
P Value < 0.005 BMC: Bone mineral Contents BMD: Bone mineral Density.
Table 3 Pearson correlation & Coefficient of Variation % between BMD & BMC in different age groups in both boys & girls for study groups. Age Groups
1 (3–5) 2 (6–8) 3(9–11) 4 (12–15)
Numbers (%)
BMD
BMC
Mean + SD
R (P Value)
Coefficient of Variation%
Mean + SD
R (P Value)
Coefficient of Variation%
Boys 82 (65.1)
Girls 33 (34.9)
Boys (0.517 ± .0.133)
Girls (0.558 ± .015)
Boys 0.576 (0.000)*
Girls 0.818 (0.000)*
Boys (32.5%) r = 0.523 P = 0.00
Girls (30.3%) r = 0.764 P = 0.000**
Boys (16.71 ± 9.1)
Girls (19.73 ± .11.5)
Boys 0.567 (0.000)*
Girls 0.831 (0.000)**
Boys r = o.523 P = 0.014
Girls (30.3%) r = 0.765 P = 0.000
33 (40.2) 27 (32.9) 19 (23.2) 3 (3.7)
13 (29.5) 14 (31.8) 7 (15.9)
0.463 ± 0.076
0.474 ± .026
10.8%
13.15 ± 3.02
13.17 ± 1.11
19.4%
15.58 ± 7.75
13.85 ± 4.76
25.8%
25.2%
0.561 ± 026
0. .543 ± 0.026 0.795 ± 133
11.6%
4.4%
20.19 ± 3.68
18.095 ± 1.06
15.8%
7.5%
52.7%
14.8%
43.93 ± 29.4
37.63 ± 11.2
0.793 (0.001*) 0.382 (0.177) 0.362 (0.424) 0.669 (0.034)*
9.0%
15.1%
0.108 (0.549) 0.298 (0.131) 0.156 (0.525) 1.000 (0.000)*
26.6%
0.474 ± .083
0.670 (0.012)* 0.230 (0.430) 0.673 (.097) 0.497 (0.144)
20.5%
0.509 ± 0.11
0.294 (0.096) 0.279 (0.159) 0.308 (0.199) 1.000 (0.000)*
34.2%
34.9%
10 (22.7)
0.915 ± .34
G.Y. Ali et al. / Egyptian Pediatric Association Gazette xxx (2017) xxx–xxx
BMD; Bone Mineral Density BMc; Bone Mineral Content P value < 0.05 is considered significant.
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Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
Table 2 Mean difference between BMC& BMD in Alhasa children and Jeddha children.
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G.Y. Ali et al. / Egyptian Pediatric Association Gazette xxx (2017) xxx–xxx
(P > 0.001). While in girls it was at the age (6–8 years) it was 19.1% (P > 0.001). In addition, peak BMD acquisition is at the ages of 13– 15 years in both sexes. Its value was more in boys than girls
(Fig. 1). BMD coefficient of variation % between age groups showed that the age (9–11 years) shows the least increase in percentage in both boys & girls (11.6%, 4.4%) respectively.
Fig. 1. Bone mineral density and bone mineral contents values in both boys and girls according to their age groups.
Table 4 Pearson correlation between Z Score and different age groups in both boys & girls. Age Groups
Numbers (%)
zscore Mean + SD
1 (3–5) 2 (6–8) 3(9–11) 4 (12–15)
r (P Value)
Boys 82 (65.1)
Girls 33 (34.9)
Boys (0. 86 ± 1.4)
Girls (0.48 ± 1.5)
Boys 0.236 (0.032)*
Girls 0.759- (0.000)**
33(40.2) 27(32.9) 19(23.2) 3(3.7)
13 (29.5) 14(31.8) 7(15.9) 10(22.7)
1.28 ± 1.66 0.74 ± 1.07 0.47 ± 1.41 0.23 ± 0.57
1.93 ± 0.58 0.75 ± 1.12 0.2571- ± 0.28 1.26 ± 1.2
0.403 (0.020)* 0.323- (0.100) 0.004-(0.987) 1.000 (0.000)
0.571 (0.042) 0.189(0.518) 0.077- (0.869) 0.116 (0.750)
P value < 0.05 is considered significant.
Fig. 2. Correlation between Z score and different age groups in both boys & girls.
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
G.Y. Ali et al. / Egyptian Pediatric Association Gazette xxx (2017) xxx–xxx
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Fig. 3. Regression analysis for effects of factors affecting BMC & BMD in boys & girls.
BMC shows statistically significant positive correlation with age Table 3 (boys r = 0.567 P > 0.001) (girls r = 0.831, P > 0.001). In girls BMC was significantly correlated with different age groups
(r = 0.831, P = 0.000). The mean ±SD of BMC is more in boys than girls (Fig. 1). BMC coefficient of variation % between age groups showed that the age (9–11 years) demonstrate the least increase
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
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G.Y. Ali et al. / Egyptian Pediatric Association Gazette xxx (2017) xxx–xxx
Table 5 Pearson correleation of factors affecting BMC, BMD, & Z-scores in boys & girls. Factors/ Bone parameters
BMD
BMC
Boys 82 R (P.Value) Height Weight BMI Calcuim level Vitamin D
0.711 0.728 0.464 0.304 0.034
(0.000)* (0.000)* (0.000)* (0.003)* (0.381)*
Z-scores
Girls 33 R (P. Value)
Boys R (P. Value)
Girls R (P. Value)
Boys R (P. Value)
Girls r(P.Value)
0.795 (0.000)* 0.792 (0.000)* 0.465 (0.001)* 0.160- (0.15) 0.412- (0.003)*
0.695 (0.000)* 0.744 (0.000)* 0.477 (0.000)* 0.322 (0.002)* 0.008- (0.472)
0.833 (0.000)* 0.800 (0.000)* 0.415 (0.003)* 0.060- (0.397) 0.274- (0.036)*
0.118- (0.145) 0.165- (0.069) 0.079- (0.245) 0.062 (0.291) 0.032 (0.389)
0.711- (0.000)* 0.648- (0.000)* 0.294- (0.026)* 0.352 (0.01)* 0.297 (0.025)*
P.Value < 0.05 is considered significant.
in the BMC % in both sexes. This mild increase follows by rapid increase content to reach maximum by age (13–15 years). The mean ± SD of Z-score of the studied group shows a steady decrease with age especially in girls (Table 4).The mean Score for boys is (0.86 ± 1.4) and in girls (0.48 ± 1.5). It shows negative correlation with age in both boys and girls (r = 0.236- P = 0.032 & r = 0.759- P = 0.000) respectively (Fig. 2). In early ages, the Zscore is more in girls than boys the reverse occurs in adolescent (Fig. 2). Z score < 2 is detected in (2.3%) of cases. All of them were girls (13–15 yrs.). Factors affects the BMD & BMC in studied children demonstrated in Fig. 3. It showed that mean BMD & BMC had significant positive correlation with the total mean height (r = 0.752, P = 0.000 & r = 0.765, P = 0.000), weight (r = 0.758, P = 0.000 & r = 0.770, P = 0.000) & BMI (r = o.468, p = 0.000 & r = 0.455, P = 0.000) in both boys & girls respectively. These parameters has positive correlation with calcium level (r = o.046 P = 0605 & r = 0.083, P = 0.358) and negative correlation with vitamin D level (r = 0.118, P = 0.187 & r = o.116, P = 0.195) respectively, which is not proved to be statistically significant. Multivariate linear regression is done to assess effects of these factors on BMD & BMC in both boys & girls (Table 5). In all participants, the Height, Weight, BMI, calcium level, Vitamin D were significantly predicting the changes in the BMC & BMD with all models. Most of these factors positively correlated with both BMC & BMD in both boys & girls. Vitamin D level is the only factor that has significant negative correlation with these parameters. The level of Vitamin D was low in 15% of cases (9% of girls and 6% in boys). Those children have low Z-score.
Discussion The measurement and interpretation of BMC and BMD in children provide unique challenges because it is affected by bone size, shape, and skeletal growth and maturation.16 The average mean of BMD& BMC in our studied Saudi children group are less consistent with the value of different races all over the world.9,17 BMD average mean and standard deviation was (0.517 ± 0.133 g/cm2) in boys and (0.558 ± .015 g/cm2) in girls. While BMC average mean was (16.71 ± 9.1) in boys and (19.73 ± 11.5) in girls. In comparison with a study done on Iranian children where BMD in boys & girls is (0.868 ± 0.118 & 0.897 ± 0.120 respectively).9 Mean BMC was low in our studied groups with no significant differences compared to other Saudi population in Jeddah. However, a significant difference noticed in BMD. It also shows no significant difference compared with south Asian population.18 The sensitivity of a childhood bone mass scan to predict peak bone mass in the normal population is low since a large proportion of individuals move between the quartiles of BMC as well as BMD during growth.6 Generally, in adults low BMD is a public health issue in Saudi Arabia and prevalence of lumbar and femur osteope-
nia ranges from 7%–43.4% and osteoporosis from 2.5–46.7% specifically in women.16 It is expected that BMD & BMC are changeable throughout growth. This study reveals that BMD & BMC changes in Saudi children is age dependent. Shepherd et al. 201119 studied BMC & BMD in over 2014 healthy US children and adolescents, they stated that in healthy children, the BMD and BMC normally increase every year until peak bone mass is attained in late adolescence or young adulthood. There is an increase in the variability of BMC and BMD with age, and the distance between percentile curves widens markedly.17 The rapid increase of them occurs towards adolescence. Which indicates that peak BMD & BMC acquisition are reached maximally between the ages of 13–15 years in both sexes. The boys have more values than girls. The peak rates of increase in bone mass accrual follow the peak in height velocity by an average of 8 months, occurring at 14 ± 1 years in boys, and 12.5 ± 0.9 years in girls.20 The annual increase of BMD shows a significant difference between age groups in both boys & girls. In boys, the greatest annual increase in BMD is at age 13–15 yrs. In girls, it is at age (6–8 y). This can be explained by near adolescence, males have higher bone mass than female, BMD is affected by bone size and site,21,14 and our study is done only in lumbar spine region which is mostly affected by pubertal changes. Sex differences in peak bone mineral of the lumbar spine are the same regardless of ethnicity.2 This study shows sex and age difference in both BMD & BMC, it is more in boys. Kang et al. 2015,2 found that there was a significant age-by-sex interaction between BMD and BMC at all skeletal sites. They found that both BMD and BMC were higher in males than in females between the ages of 10 and 25 years. The reverse was noticed in a study done by Jeddi et al., 2013,9 reported that spine BMD is higher in girls than in boys until late adolescence. However, these gender differences at the spine disappear in late adolescence as boys catch up with puberty and growth.17 In children, Z-scores is the index used throughout the childhood and adolescence to assess affection of bone mineral content and any decrease in Z score > 2 SD this mean low BMD.3 In this study Z- scores shows a steady decrease with age especially in girls. However, the mean z-scores is within the normal value of both sex and with no significant difference. Z- Score <- 2SD was detected in 2.3% of cases all of them was adolescence girls with no significant difference between sex. Height, weight & BMI show a positive correlation with mean BMD & BMC in both boys & girls. Jeddi et al. 20139 stated that the relationship between BMD, BMC and height is much stronger than the relationship between BMD, BMC, and age, especially in girls which is similar to our study. No distinct sex difference is observed during puberty when the change in BMI pattern was analyzed.2 In this study height, weight, BMI, calcium level, vitamin D level significantly predict the changes in the BMC & BMD. Most of these factors show significant positive correlation with both BMC & BMD
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
G.Y. Ali et al. / Egyptian Pediatric Association Gazette xxx (2017) xxx–xxx
in both boys & girls. Vitamin D level is the only factor that has a non-significant negative correlation with these parameters. This agreed with Jeddi et al. 2013,9 who found that by multivariate linear regression analysis, there is no significant effect of vitamin D status on BMD or BMC. This can be explained by 15% of our cases have a low level of Vitamin D. Even in a country that receives many hours of sunlight in most areas, Vitamin D deficiency common among healthy children and adolescents. There are few data in KSA showing an association between poor vitamin D status and indices of bone health of cases.22 In a study done in Jeddah, KSA by Al-Ghamdi et al. 2012,15 they showed a significant positive correlation was found between 25OHD status and BMD in the 6–9 years and 13–14 year age categories in school-aged Saudi Arabian boys and girls. While No significant correlations were found between 25OHD status and bone health in the other age categories boys & the older girls. They explained that by, low number of participants in this older age group for the females. Conclusion The average bone density (BMD) of Saudi children and adolescents is less than that of other races like American, Brazilian, and Iranian children. Low BMD & Z-score > 2 was found in 2.3% of girls especially in adolescence. Boys have more BMD & BMC than girls in all age groups. Weight, height, BMI are good predictive for changes in BMD & BMC all over a period of growth. Vitamin D in our study shows less effect in changes in BMD and BMC. Our recommendation is to expand this study to involve whole Kingdom. Follow up especially to adolescence females to detect early abnormalities in bone parameters. Finally, bone health parameters of Saudi children in Alhasa can be database reference in the present study may provide clinicians with useful information that will allow for the proper care of healthy children. Our study strength points is that it give a hint about the values of BMC & BMD Saudi children in eastern region in KSA. This part of kingdom has hot climate with low exposure to sun light. As bone parameters affected by race and environmental condition. These values should be monitored and expand the study to have percentile values to all Saudi population. Knowing children at risk for low BMD is a key to prevent osteoporosis early in life. The limitation of this study is the small number especially in adolescence. Conflict of interest All authors shows no conflict of interest. Acknowledgments This research received grant from and done under supervision of Dean of scientific Affairs, king Feisal University. Research number (140136). Our grateful to Dr. Khalid and Dr. Ebtesam and all
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radiology and lab technician in the University Polyclinic center for their support and aids during collection of samples. Our great thanks to the participants, their parents.
References [1] Ma NS, Gordon CM. Pediatric osteoporosis: where are we now?. J Pediatr. 2012;161:983–990. [2] Kang MJ, Hong HS, Chung SJ, et al. Body composition and bone density reference data for Korean children, adolescents, and young adults according to age and sex: results of the 2009–2010 Korean National Health and Nutrition Examination Survey (KNHANES). J Bone Miner Metab. 2015. [3] Stagi S, Cavalli L, Iurato C. Bone health in children and adolescents: the available imaging techniques. Bone Metab. 2013;10:166–171. [4] Sawyer AJ, Bachrach LK, Fung EF, eds. Bone Densitometry in Growing Patients: Guidelines for Clinical Practice. Totowa, New Jersey: Humana Press; 2007. [5] Horlick M, Wang J, Pierson Jr RN, et al. Prediction models for evaluation of total-body bone mass with dual-energy X-ray absorptiometry among children and adolescents. Pediatrics. 2004;114:e337–e345. [6] Buttazzoni C, Rosengren BE, Karlsson C, et al. A pediatric bone mass scan has poor ability to predict peak bone mass: an 11-year prospective study in 121 children. Calcif Tissue Int. 2015;96:379–388. [7] Heaney RP, Abrams S, Dawson-Hughes B, et al. Peak bone mass. Osteoporos Int. 2000;11:985–1009. [8] Bachrach LB, Sills IN. Clinical report-bone densitometry in children and adolescents. Pediatrics. 2011;127 [9] Jeddi M, Roosta MJ, Dabbaghmanesh MH, et al. Normative data and percentile curves of bone mineral density in healthy Iranian children aged 9–18 years. Arch Osteoporos. 2013;8:114. http://dx.doi.org/10.1007/s11657-012-0114-z. [10] Guglielmi G, Muscarella S, Bazzocchi A. Integrated imaging approach to osteoporosis: state-of-the-art review and update. RadioGraphics. 2011;31: 1343–1364. [11] Binkovitz LA, Henwood MJ. Pediatric DXA: technique and interpretation. Pediatr Radiol. 2007;37:21–31. [12] Sheridan K. Assessing bone health in children DXA scans play a vital role in management. Pediatr Persp. 2010;19. [13] Zemel B, Leonard MB, Kelly A, Lappe JM. Height adjustment in assessing dual energy X-ray absorptiometry measurements of bone mass and density in children. J Clin Endocrinol Metab. 2010;95:1265–1273. [14] Fewtrell MS. British paediatric and adolescent bone group bone densitometry in children assessed by dual X-ray absorptiometry: uses and pitfalls. Arch Dis Child. 2003;88:795–798. [15] Al-Ghamdi M, Lanham SA, Kahn JA. Differences in vitamin D status and calcium metabolism in Saudi Arabian boys and girls aged 6 to 18 years: effects of age, gender, extent of veiling and physical activity with concomitant implications for bone health. Public Health Nutr. 2012;15:1845–1853. [16] AlQuaiz AM, Kazi A, Tayel S, et al. Prevalence and factors associated with low bone mineral density in Saudi women: a community based survey. BMC Musculoskelet Disord. 2014;15 [17] Kalkwarf HJ, Zemel BS, Gilsanz V, et al. The bone mineral density in childhood study: bone mineral content and density according to age, sex, and race. J Clin Endocrinol Metab. 2007;92:2087–2099. [18] Nakavachara P, Pooliam J, Weerakulwattana L, et al.: A normal reference of bone mineral density (BMD) measured by dual energy x-ray absorptiometry in healthy thai children and adolescents aged 5–18 years: a new reference for southeast asian populations. PLoS One, 2014;9:e 972189. doi:10.1371. [19] Shepherd JA, Wang L, Fan B, et al. Optimal monitoring time interval between DXA measures in children. J Bone Miner Res. 2011;26:2745–2752. http://dx. doi.org/10.1002/jbmr.473. [20] Gelfand IN, DiMeglio LA. Bone Mineral Accrual and Low Bone Mass: A Pediatric Perspective. Rev. Endocr. Metab. Disord.. 2005;6:281–289. [21] Golden NH, Abrams SA. Optimizing Bone Health in Children and Adolescents Pediatrics 2014;134. [22] Kelly TL, Specker BL, Binkley T, et al. Pediatric BMD reference database for U.S. white children. Bone. 2005;36(Suppl. 1):S30.
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
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Egyptian Pediatric Association Gazette journal homepage: www.elsevier.com/locate/epag
Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan Gihan Yousef Ali a,b,⇑, Essam Eldin Abdelbary c,d, Waleed Hamad Albuali a, Nagah Mohamed AboelFetoh b, Eglal Hussein AlGohary a a
Pediatric Department, College of Medicine, KFU, Alhasa, Mail box: 400, Saudi Arabia Sohag College of Medicine, Sohag University, Egypt c Radiology Department, Sohag College of Medicine, Sohag University, Egypt d King Feisal University, College of Medicine, Surgery Department, Alhasa, Mail box: 400, Saudi Arabia b
a r t i c l e
i n f o
Article history: Received 29 November 2016 Accepted 20 March 2017 Available online xxxx Keywords: Bone mineral density Bone mineral contents Dexa scan Children Saudi Arabia
a b s t r a c t Objectives: Optimization of bone health is a very important concern now a day. Achievement of optimal peak bone mineral mass is the best means of preventing osteoporosis in adulthood. Dual-energy X-ray absorptiometry (DXA) has become the basis for the evaluation of skeletal health in all ages. The aim of the work: This work aims to assess bone parameters in Alhasa children, Saudi Arabia. Patient & methods: A Cross-sectional survey study involves 126 healthy children (83) boys & (43) girls. Their ages range from (3–15 years). Results: The mean of Bone mineral density (BMD) and bone mineral content (BMC) were (0.915 ± 0.34 & 0.795 ± 0.133) (43.93 ± 29.4 & 37.63 ± 11.2) in boys and in girls respectively. These values were lower than other areas in Saudi Arabia. BMD & BMC are statistically significant positive correlation with age in both sex, (r = 0.567 P = 0.000 & r = 0.57 P < 0.001) and (r = 0.831, P = 0.000 & r = 0.818 P < 0.001) respectively. Level of BMD & BMC acquisition were more in boys than girls in all age groups especially group (12–15 years). The mean Z score shows significant steady decrease with age in both sexes. Height, Weight, BMI, showed significant positive correlations with changes in BMD & BMC. While Calcium level and Vitamin D level showed negative correlations. Conclusion: The average BMD & BMC in Saudi children is less than that of other races. It shows no significant difference with other Saudi population. Height, weight, BMI Calcium level and Vitamin D level can predict the changes in the BMC & BMD. Ó 2017 The Egyptian Pediatric Association. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Introduction Bone is a highly ‘‘dynamic” and specialized connective tissue; its main function is to provide a mechanical support & mineral homeostasis to the human body.1 Over the last decade, the bone health monitoring is increasingly important, especially in the pediatric population.2
Peer review under responsibility of Egyptian Pediatric Association Gazette. ⇑ Corresponding author at: Pediatric Department, College of Medicine, KFU, Alhasa, Mail box: 400, Saudi Arabia, Pediatric Department, Sohag College of Medicine, Sohag University, Egypt. E-mail addresses: [email protected], [email protected], jyousef@kfu. edu.sa (G.Y. Ali), [email protected] (E.E. Abdelbary), [email protected] (W.H. Albuali), [email protected] (N.M. AboelFetoh), dreglalhs@gmail. com (E.H. AlGohary).
Bone mass shows a progressive increase from the birth, until the third decade of life, when it reaches a maximum value defined ‘‘peak bone mass.3 Peak bone mineral accrual occurs during early puberty while peak bone mass is achieved in young adulthood.4 Achievement of optimal peak bone mineral mass is the best means of preventing osteoporosis in adulthood.5 The accrual of Bone Mineral Density (BMD) during growth has therefore arise interest; there is an ongoing debate on whether a low BMD in childhood predicts a low BMD in adulthood.6 As bone properties change rapidly during growth, making a prediction on adult BMD from childhood measurements is difficult. Serial measurements cover both the pre-pubertal and postpubertal phases is important for accurate predictions.7 Several factors influence the mineralization of bones in childhood and adolescence, including genetic factors, sex, nutrition, endocrine factors, and mechanical factors.8
http://dx.doi.org/10.1016/j.epag.2017.03.005 1110-6638/Ó 2017 The Egyptian Pediatric Association. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
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Low bone mineral density is the primary cause of compromised bone health. Many factors can contribute to low bone mineral density. Unfortunately, in Saudi Arabia genetic background, customs, diet, and geographical location is identified as predisposing factors for osteoporosis.9 In children Low bone mass is usually suspected after X-rays demonstrate osteopenia, after a low-trauma fracture, or when a child has a known disorder associated with low bone mass. Nowadays, the widest method to assess BMD& Bone mineral contents (BMC) is Dual-energy X-ray absorptiometry (DXA). It becomes the basis for the evaluation of skeletal health in all ages. It assesses BMD, BMC, and body composition.10 The International Society for Clinical Densitometry recommends a skeletal status evaluation in children and adolescents based on age-, sex-, and ethnicity-specific normative Ref. [11] DXA scan is now considered the standard reference for defining the rate of mineralization in the total skeleton in different regions. The dose of the DXA radiation is extremely low (5–10 u Sv). It generally takes 5–10 min to be performed, rarely needs sedation and low cost.8 DXA scan can identify bone-density losses of as little as 3%.12 It is by far, the most widely used unique technique for measuring BMD in children .11 The interpretation of DXA values in children is much more difficult than in adults because the skeleton is continuously changing and there is no precise point of reference. It has some limitations, especially in children. Bone size varies less in adults than in growing children. Particularly during the rapid growth phase of puberty, thus age and puberty maturation are important considerations.3,13 Most bone Densitometers in children report BMD as a Z score, related to an age-matched (and sometimes gender or ethnic group matched population.14 This study is designed to screen for BMD and BMC in Saudi children. To detect their relation with anthropometric measure. Study factor affecting their changes especially the serum Calcium, Vitamin D level. Patients & methods This cross-sectional study performed in King Feisal university polyclinic, in a period from 2012–2014, 126 patients were included in this study. They were 82 (65.9%) males and 44 (34.1%) females. Inclusion criteria Age more than 3 years of age, and apparently healthy children. Exclusion criteria Children whom Parents refuse to scan and Children with any chronic illness.
Dean of scientific affairs & Ethical comities in the university and polyclinic approved the study Parent’s verbal consent to perform DEXA scan to their children was also obtained. Complete history with special inquire about age, sex, history of previous fracture, blood transfusion, lifestyle and receiving drugs was obtained. Complete examination with comment in the weight, height, and any manifestation of chronic illness was done. A Blood sample was taken for estimation of serum calcium, and active Vitamin D level. DXA scan was using (GE Excel DXA – compact pencil beam axial scanner) present in the polyclinic, BMC measured in grams bone area (BA), and BMD (in gram/square centimeter) from the lumbar spine (LS) (L1–L4). The position size and location of the region were the same for all children. The machine that is adjusted to specific age- and sex- reference data calculates Zscores automatically. The scan was analyzed and diagnosed by an experienced consultant of radiology, with more than 20 years’ experience. Statistical analysis Results were analyzed using SPSS program version 21 for Windows. Statistical descriptive data were reported as mean ± SD. Association of variables was tested with Pearson or Spearman correlation. Simple regression analysis was first performed to screen potential predictors for BMD & BMC and a multivariate stepwise linear regression model was used to identify and determine significant predictors for bone mass. A P-value of less than 0.05 was considered statistically significant. Results This study include 126 healthy children, they were 65.1% (n: 82) males and 34.9% (n: 44) females. Their anthropometric parameters are shown in the Table 1. The children grouped according to gender and age into 4 groups. The mean ±SD of BMC & BMD in the studied group are demonstrated in Table 2. A comparison between Bone parameters in our cases and other areas in Saudi Arabia shows that our cases have BMD&BMC means less than other in Jeddah study done by Al-Ghamdi et al. 2012,15 these difference is not significant in BMC while there is a significant difference in their BMD in all age groups. The estimated BMD in both boys & girls Table 3. BMD changes shows significant positive correlation with age in both sexes, (boys r = 0.57 P > 0.001) (girls r = 0.818 P > 0.001). Maximum annual increase in BMD in boys was in age (13–15 yrs.), it was 52.7%
Table 1 Anthropometric parameters for study groups. Age Groups
1 (3–5) 2 (6–8) 3(9–11) 4 (12–15)
Numbers (%)
Height (cm)
BMI (kg/m2)
Weight (kg)
Mean + SD
C V%
Mean + SD
C V%
Mean + SD
C V%
Boys 82 (65.1)
Girls 33 (34.9)
Boys (119.2 ± 15.73)
Girls (127.4 ± 20.3)
Boys
Girls
Boys (22.3 ± 10.1)
Girls (26.6 ± 10.8)
Boys
Girls
Boys (14.9 ± 2.4)
Girls (15.4 ± 2.2)
Boys
Girls
33 (40.2) 27 (32.9) 19 (23.2) 3 (3.7)
13 (29.5) 14 (31.8) 7 (15.9) 10 (22.7)
108.1 ± 7.1
107.15 ± 4
6.6
4.3
17.25 ± 2.5
17.6 ± 0.7
14.3
10.0
14.40 ± 1.4
14.77 ± 1.2
9.3
8.9
118.2 ± 9
121.3 ± 11.7
7.7
9.7
20.55 ± 3.8
23.15 ± 9.0
16.8
25.9
14.46 ± 1.3
14.6 ± 1.2
7.3
16.8
132.8 ± 10.88
134.3 ± 7.9
10.4
6.4
26.7 ± 4.8
28.2 ± 3.8
23.3
15.0
14.86 ± 2.23
15.68 ± .9
13.3
5.6
164.66 ± 12.7
157.4 ± 4.9
10.4
3.3
66.33 ± 9.8
41.9 ± 5.3
21.9
13.0
24.07 ± .0.46
16.8 ± 2.3
2.4
13.4
Coefficient of Variation %.
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
Age groups
Mean ± SD of BMC (gm) Boys
Group 1 (3–5) Group2 (6–8) Group 3 (9–11) Group4 (12–15)
Mean ± SD of BMD (gm/cm2) Boys
P value
Ahasa
Jeddah
No.33 13.15 ± 3.02 No.27 15.58 ± 7.7 No.19 20.19 ± 3.6 No.3 43.94 ± 29.45
NO. 42 19.3 ± 6.4 No.59 25.5 ± 6.8 No.30 28 ± 8.2 No.19 37.7 ± 6.4
0.999 0.201 0.999 0.624
Ahasa
Jeddah
No. 33 0.46 ± 0.076 NO. 27 0.51 ± 0.11 No. 19 0.56 ± 0.07 No. 3 0.92 ± 0.34
No. 42 0.74 ± 0.12 No. 59 0.82 ± 0.1 No. 30 0.84 ± 0.14 No. 19 0.95 ± 0.06
P value
Mean ± SD of BMC (gm) Girls Ahasa
Jeddah
0.000*
NO: 3 13.18 ± 1.1 No.14 13.86 ± 4.7 No.7 18.1 ± 1.04 No.10 37.63 ± 11.2
No.40 16.8 ± 5.5 No. 57 29.3 ± 9.8 No. 42 30.4 ± 8.8 No.11 35.4 ± 12.9
0.000* 0.000* 0.88
P value
Mean ± SD of BMD (gm/cm2) Girls Ahasa
Jeddah
1
N0. 13 0.47 ± .02 No. 14 0.47 ± 0.08 No. 7 0.54 ± 0.03 No.10 0.79 ± 0.13
N0. 40 0.73 ± 0.09 No. 57 0.92 ± 0.19 No. 42 0.94 ± 0.17 No.11 1.04 ± 0.19
0.999 1 0.574
P value
0.000* 0.000* 0.000* 0.002*
P Value < 0.005 BMC: Bone mineral Contents BMD: Bone mineral Density.
Table 3 Pearson correlation & Coefficient of Variation % between BMD & BMC in different age groups in both boys & girls for study groups. Age Groups
1 (3–5) 2 (6–8) 3(9–11) 4 (12–15)
Numbers (%)
BMD
BMC
Mean + SD
R (P Value)
Coefficient of Variation%
Mean + SD
R (P Value)
Coefficient of Variation%
Boys 82 (65.1)
Girls 33 (34.9)
Boys (0.517 ± .0.133)
Girls (0.558 ± .015)
Boys 0.576 (0.000)*
Girls 0.818 (0.000)*
Boys (32.5%) r = 0.523 P = 0.00
Girls (30.3%) r = 0.764 P = 0.000**
Boys (16.71 ± 9.1)
Girls (19.73 ± .11.5)
Boys 0.567 (0.000)*
Girls 0.831 (0.000)**
Boys r = o.523 P = 0.014
Girls (30.3%) r = 0.765 P = 0.000
33 (40.2) 27 (32.9) 19 (23.2) 3 (3.7)
13 (29.5) 14 (31.8) 7 (15.9)
0.463 ± 0.076
0.474 ± .026
10.8%
13.15 ± 3.02
13.17 ± 1.11
19.4%
15.58 ± 7.75
13.85 ± 4.76
25.8%
25.2%
0.561 ± 026
0. .543 ± 0.026 0.795 ± 133
11.6%
4.4%
20.19 ± 3.68
18.095 ± 1.06
15.8%
7.5%
52.7%
14.8%
43.93 ± 29.4
37.63 ± 11.2
0.793 (0.001*) 0.382 (0.177) 0.362 (0.424) 0.669 (0.034)*
9.0%
15.1%
0.108 (0.549) 0.298 (0.131) 0.156 (0.525) 1.000 (0.000)*
26.6%
0.474 ± .083
0.670 (0.012)* 0.230 (0.430) 0.673 (.097) 0.497 (0.144)
20.5%
0.509 ± 0.11
0.294 (0.096) 0.279 (0.159) 0.308 (0.199) 1.000 (0.000)*
34.2%
34.9%
10 (22.7)
0.915 ± .34
G.Y. Ali et al. / Egyptian Pediatric Association Gazette xxx (2017) xxx–xxx
BMD; Bone Mineral Density BMc; Bone Mineral Content P value < 0.05 is considered significant.
3
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
Table 2 Mean difference between BMC& BMD in Alhasa children and Jeddha children.
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(P > 0.001). While in girls it was at the age (6–8 years) it was 19.1% (P > 0.001). In addition, peak BMD acquisition is at the ages of 13– 15 years in both sexes. Its value was more in boys than girls
(Fig. 1). BMD coefficient of variation % between age groups showed that the age (9–11 years) shows the least increase in percentage in both boys & girls (11.6%, 4.4%) respectively.
Fig. 1. Bone mineral density and bone mineral contents values in both boys and girls according to their age groups.
Table 4 Pearson correlation between Z Score and different age groups in both boys & girls. Age Groups
Numbers (%)
zscore Mean + SD
1 (3–5) 2 (6–8) 3(9–11) 4 (12–15)
r (P Value)
Boys 82 (65.1)
Girls 33 (34.9)
Boys (0. 86 ± 1.4)
Girls (0.48 ± 1.5)
Boys 0.236 (0.032)*
Girls 0.759- (0.000)**
33(40.2) 27(32.9) 19(23.2) 3(3.7)
13 (29.5) 14(31.8) 7(15.9) 10(22.7)
1.28 ± 1.66 0.74 ± 1.07 0.47 ± 1.41 0.23 ± 0.57
1.93 ± 0.58 0.75 ± 1.12 0.2571- ± 0.28 1.26 ± 1.2
0.403 (0.020)* 0.323- (0.100) 0.004-(0.987) 1.000 (0.000)
0.571 (0.042) 0.189(0.518) 0.077- (0.869) 0.116 (0.750)
P value < 0.05 is considered significant.
Fig. 2. Correlation between Z score and different age groups in both boys & girls.
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
G.Y. Ali et al. / Egyptian Pediatric Association Gazette xxx (2017) xxx–xxx
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Fig. 3. Regression analysis for effects of factors affecting BMC & BMD in boys & girls.
BMC shows statistically significant positive correlation with age Table 3 (boys r = 0.567 P > 0.001) (girls r = 0.831, P > 0.001). In girls BMC was significantly correlated with different age groups
(r = 0.831, P = 0.000). The mean ±SD of BMC is more in boys than girls (Fig. 1). BMC coefficient of variation % between age groups showed that the age (9–11 years) demonstrate the least increase
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
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G.Y. Ali et al. / Egyptian Pediatric Association Gazette xxx (2017) xxx–xxx
Table 5 Pearson correleation of factors affecting BMC, BMD, & Z-scores in boys & girls. Factors/ Bone parameters
BMD
BMC
Boys 82 R (P.Value) Height Weight BMI Calcuim level Vitamin D
0.711 0.728 0.464 0.304 0.034
(0.000)* (0.000)* (0.000)* (0.003)* (0.381)*
Z-scores
Girls 33 R (P. Value)
Boys R (P. Value)
Girls R (P. Value)
Boys R (P. Value)
Girls r(P.Value)
0.795 (0.000)* 0.792 (0.000)* 0.465 (0.001)* 0.160- (0.15) 0.412- (0.003)*
0.695 (0.000)* 0.744 (0.000)* 0.477 (0.000)* 0.322 (0.002)* 0.008- (0.472)
0.833 (0.000)* 0.800 (0.000)* 0.415 (0.003)* 0.060- (0.397) 0.274- (0.036)*
0.118- (0.145) 0.165- (0.069) 0.079- (0.245) 0.062 (0.291) 0.032 (0.389)
0.711- (0.000)* 0.648- (0.000)* 0.294- (0.026)* 0.352 (0.01)* 0.297 (0.025)*
P.Value < 0.05 is considered significant.
in the BMC % in both sexes. This mild increase follows by rapid increase content to reach maximum by age (13–15 years). The mean ± SD of Z-score of the studied group shows a steady decrease with age especially in girls (Table 4).The mean Score for boys is (0.86 ± 1.4) and in girls (0.48 ± 1.5). It shows negative correlation with age in both boys and girls (r = 0.236- P = 0.032 & r = 0.759- P = 0.000) respectively (Fig. 2). In early ages, the Zscore is more in girls than boys the reverse occurs in adolescent (Fig. 2). Z score < 2 is detected in (2.3%) of cases. All of them were girls (13–15 yrs.). Factors affects the BMD & BMC in studied children demonstrated in Fig. 3. It showed that mean BMD & BMC had significant positive correlation with the total mean height (r = 0.752, P = 0.000 & r = 0.765, P = 0.000), weight (r = 0.758, P = 0.000 & r = 0.770, P = 0.000) & BMI (r = o.468, p = 0.000 & r = 0.455, P = 0.000) in both boys & girls respectively. These parameters has positive correlation with calcium level (r = o.046 P = 0605 & r = 0.083, P = 0.358) and negative correlation with vitamin D level (r = 0.118, P = 0.187 & r = o.116, P = 0.195) respectively, which is not proved to be statistically significant. Multivariate linear regression is done to assess effects of these factors on BMD & BMC in both boys & girls (Table 5). In all participants, the Height, Weight, BMI, calcium level, Vitamin D were significantly predicting the changes in the BMC & BMD with all models. Most of these factors positively correlated with both BMC & BMD in both boys & girls. Vitamin D level is the only factor that has significant negative correlation with these parameters. The level of Vitamin D was low in 15% of cases (9% of girls and 6% in boys). Those children have low Z-score.
Discussion The measurement and interpretation of BMC and BMD in children provide unique challenges because it is affected by bone size, shape, and skeletal growth and maturation.16 The average mean of BMD& BMC in our studied Saudi children group are less consistent with the value of different races all over the world.9,17 BMD average mean and standard deviation was (0.517 ± 0.133 g/cm2) in boys and (0.558 ± .015 g/cm2) in girls. While BMC average mean was (16.71 ± 9.1) in boys and (19.73 ± 11.5) in girls. In comparison with a study done on Iranian children where BMD in boys & girls is (0.868 ± 0.118 & 0.897 ± 0.120 respectively).9 Mean BMC was low in our studied groups with no significant differences compared to other Saudi population in Jeddah. However, a significant difference noticed in BMD. It also shows no significant difference compared with south Asian population.18 The sensitivity of a childhood bone mass scan to predict peak bone mass in the normal population is low since a large proportion of individuals move between the quartiles of BMC as well as BMD during growth.6 Generally, in adults low BMD is a public health issue in Saudi Arabia and prevalence of lumbar and femur osteope-
nia ranges from 7%–43.4% and osteoporosis from 2.5–46.7% specifically in women.16 It is expected that BMD & BMC are changeable throughout growth. This study reveals that BMD & BMC changes in Saudi children is age dependent. Shepherd et al. 201119 studied BMC & BMD in over 2014 healthy US children and adolescents, they stated that in healthy children, the BMD and BMC normally increase every year until peak bone mass is attained in late adolescence or young adulthood. There is an increase in the variability of BMC and BMD with age, and the distance between percentile curves widens markedly.17 The rapid increase of them occurs towards adolescence. Which indicates that peak BMD & BMC acquisition are reached maximally between the ages of 13–15 years in both sexes. The boys have more values than girls. The peak rates of increase in bone mass accrual follow the peak in height velocity by an average of 8 months, occurring at 14 ± 1 years in boys, and 12.5 ± 0.9 years in girls.20 The annual increase of BMD shows a significant difference between age groups in both boys & girls. In boys, the greatest annual increase in BMD is at age 13–15 yrs. In girls, it is at age (6–8 y). This can be explained by near adolescence, males have higher bone mass than female, BMD is affected by bone size and site,21,14 and our study is done only in lumbar spine region which is mostly affected by pubertal changes. Sex differences in peak bone mineral of the lumbar spine are the same regardless of ethnicity.2 This study shows sex and age difference in both BMD & BMC, it is more in boys. Kang et al. 2015,2 found that there was a significant age-by-sex interaction between BMD and BMC at all skeletal sites. They found that both BMD and BMC were higher in males than in females between the ages of 10 and 25 years. The reverse was noticed in a study done by Jeddi et al., 2013,9 reported that spine BMD is higher in girls than in boys until late adolescence. However, these gender differences at the spine disappear in late adolescence as boys catch up with puberty and growth.17 In children, Z-scores is the index used throughout the childhood and adolescence to assess affection of bone mineral content and any decrease in Z score > 2 SD this mean low BMD.3 In this study Z- scores shows a steady decrease with age especially in girls. However, the mean z-scores is within the normal value of both sex and with no significant difference. Z- Score <- 2SD was detected in 2.3% of cases all of them was adolescence girls with no significant difference between sex. Height, weight & BMI show a positive correlation with mean BMD & BMC in both boys & girls. Jeddi et al. 20139 stated that the relationship between BMD, BMC and height is much stronger than the relationship between BMD, BMC, and age, especially in girls which is similar to our study. No distinct sex difference is observed during puberty when the change in BMI pattern was analyzed.2 In this study height, weight, BMI, calcium level, vitamin D level significantly predict the changes in the BMC & BMD. Most of these factors show significant positive correlation with both BMC & BMD
Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005
G.Y. Ali et al. / Egyptian Pediatric Association Gazette xxx (2017) xxx–xxx
in both boys & girls. Vitamin D level is the only factor that has a non-significant negative correlation with these parameters. This agreed with Jeddi et al. 2013,9 who found that by multivariate linear regression analysis, there is no significant effect of vitamin D status on BMD or BMC. This can be explained by 15% of our cases have a low level of Vitamin D. Even in a country that receives many hours of sunlight in most areas, Vitamin D deficiency common among healthy children and adolescents. There are few data in KSA showing an association between poor vitamin D status and indices of bone health of cases.22 In a study done in Jeddah, KSA by Al-Ghamdi et al. 2012,15 they showed a significant positive correlation was found between 25OHD status and BMD in the 6–9 years and 13–14 year age categories in school-aged Saudi Arabian boys and girls. While No significant correlations were found between 25OHD status and bone health in the other age categories boys & the older girls. They explained that by, low number of participants in this older age group for the females. Conclusion The average bone density (BMD) of Saudi children and adolescents is less than that of other races like American, Brazilian, and Iranian children. Low BMD & Z-score > 2 was found in 2.3% of girls especially in adolescence. Boys have more BMD & BMC than girls in all age groups. Weight, height, BMI are good predictive for changes in BMD & BMC all over a period of growth. Vitamin D in our study shows less effect in changes in BMD and BMC. Our recommendation is to expand this study to involve whole Kingdom. Follow up especially to adolescence females to detect early abnormalities in bone parameters. Finally, bone health parameters of Saudi children in Alhasa can be database reference in the present study may provide clinicians with useful information that will allow for the proper care of healthy children. Our study strength points is that it give a hint about the values of BMC & BMD Saudi children in eastern region in KSA. This part of kingdom has hot climate with low exposure to sun light. As bone parameters affected by race and environmental condition. These values should be monitored and expand the study to have percentile values to all Saudi population. Knowing children at risk for low BMD is a key to prevent osteoporosis early in life. The limitation of this study is the small number especially in adolescence. Conflict of interest All authors shows no conflict of interest. Acknowledgments This research received grant from and done under supervision of Dean of scientific Affairs, king Feisal University. Research number (140136). Our grateful to Dr. Khalid and Dr. Ebtesam and all
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radiology and lab technician in the University Polyclinic center for their support and aids during collection of samples. Our great thanks to the participants, their parents.
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Please cite this article in press as: Ali G.Y., et al. Bone mineral density & bone mineral content in Saudi children, risk factors and early detection of their affection using dual-emission X-ray absorptiometry (DEXA) scan. Egypt Pediatr Assoc Gazette (2017), http://dx.doi.org/10.1016/j.epag.2017.03.005