Prevalence of Incorrect Posture among Children and Adolescents: Finding from a Large Population-Based Study in China.

Evidence showed that bad posture in adulthood is often formed from the childhood, and individuals with severe incorrect posture may be associated with the progress of scoliosis. We aimed to estimate the prevalence of incorrect posture in Chinese children and adolescents and to describe the epidemiological findings stratified by the demographic characteristics. A total of 595,057 students were screened; the overall prevalence of incorrect posture in children and adolescents was 65.3%, and around 3.7% of the students were referred to radiography. Girls had a higher prevalence of incorrect posture than boys, students aged >10 years accounted for a higher rate of incorrect posture than students aged <10 years. We found that Chinese children and adolescents had a high prevalence of incorrect posture, with girls and older students being an especially high-risk group. Early interventions targeted for students with incorrect posture are urgently needed.

Introduction

Incorrect posture refers to an abnormal body state in which the body cannot maintain a stable state and the normal function of tissues and organs in an upright state (Dolphens et al., 2012). Previous studies have shown that the bad posture in adulthood is often formed from the childhood (Louw et al., 2007). Severe incorrect posture in children and adolescents with may be associated with progress to adolescent idiopathic scoliosis (Nissinen et al., 1993, Nault et al., 2002). Moreover, untreated incorrect posture was shown to be associated with the reduction in cardiorespiratory efficiency, decreased vital capacity of lungs, low back pains, and the displacement of internal organs (Yu et al., 2002). Understanding the current prevalence of incorrect posture of children and adolescents will help to identify high-risk population and formulate targeted interventions.

Previous studies showed that 34%–50% children and adolescents have different degrees of incorrect posture (Motylewski et al., 2016, Mahlknecht, 2007); less than a fifth of children and adolescents have a correct body posture (Kamal, 2008); most of the children have certain incorrect posture problems (e.g., shoulder asymmetry, thoracic kyphosis, or scapula tilt). Furthermore, some researchers suggested that compared with children of the same age who have not received school education, students who have received school education have more serious body posture problems (Macialczykpaprocka et al., 2017, Kasten et al., 2017).

To the best of our knowledge, previous evidence mainly comes from the Western or developed countries. In China, only one school screening program conducted in Beijing showed that nearly 80% children and adolescents were reported to have at least one sign of incorrect postures (Xing, 2018). However, there is still a lack of population-based epidemiological evidence in the prevalence of adolescent incorrect posture.

Therefore, we conducted this large-scale cross-sectional study in south China to estimate the prevalence of incorrect posture among children and adolescents, to describe the epidemiological findings stratified by the demographic characteristics, which will provide data support to find out high-risk population and develop targeted interventions.

Results

Demographic Characteristics of Chinese Children and Adolescents

The sample demographic information is shown in Table 1. A total of 595,057 Chinese children and adolescents were screened, among which 54.6% were boys and 45.4% were girls, yielding a male-to-female ratio of 1.2:1, and the mean (SD) age of the students was 12.8 ± 2.0 years. Primary school, junior high school, and senior high school students account for 38.0%, 42.7%, and 19.3%, respectively.

Table 1

Demographic Characteristics of Chinese Children and Adolescents (N = 595,057)

Variables	N (%)
Gender
Boy	3,24,932 (54.6)
Girl	2,70,125 (45.4)
Age (year, mean ± SD)	12.8 ± 2.0
Ethnic group
Han	5,77,205 (97.0)
Minority	17,852 (3.0)
School category
Primary school	2,26,121 (38.0)
Junior high school	2,54,089 (42.7)
Senior high school	1,14,847 (19.3)
Grade (age [years], mean ± SD)
Grade 1 (7.26 ± 1.09)	1,190 (0.2)
Grade 2 (8.11 ± 0.98)	1,785 (0.3)
Grade 3 (9.35 ± 1.12)	1,796 (0.3)
Grade 4 (10.44 ± 0.89)	1,856 (0.3)
Grade 5 (11.40 ± 0.56)	1,13,060 (19.0)
Grade 6 (12.37 ± 0.44)	1,06,515 (17.9)
Grade 7 (13.30 ± 0.39)	91,638 (15.4)
Grade 8 (14.29 ± 0.45)	89,258 (15.0)
Grade 9 (15.32 ± 0.37)	72,596 (12.2)
Grade 10 (16.24 ± 0.42)	59,505 (10.0)
Grade 11 (17.28 ± 0.51)	53,555 (9.0)
Grade 12 (18.24 ± 0.79)	2,303 (0.4)

N, number; SD, standard deviation.

Prevalence of Incorrect Posture of Chinese Children and Adolescents

As shown in Table 2, the overall prevalence of incorrect posture among Chinese children and adolescents was 65.3% (95% confidence interval [CI]: 65.0%–65.5%), and around 3.7% (95% CI: 3.6%–3.8%) children and adolescents were referred for radiography. The most serious sign of incorrect posture was high and low shoulders (left shoulder height: 30.2%, 95% CI: 30.0%–30.5%; right shoulder height: 24.5%, 95% CI: 24.2%–24.7%) and scapula tilt (tilt to the left: 25.2%, 95% CI: 25.0%–25.5%; tilt to the right: 17.0%, 95% CI: 16.8%–17.1%).

Table 2

Prevalence of Incorrect Posture among Chinese Children and Adolescents (N = 595,057)

Variables	N (%)	95% CI
Total	5,95,057 (100.0)	–
High and low shoulder
Normal	2,69,560 (45.3)	45.1%–45.6%
Left shoulder height	1,79,707 (30.2)	30.0%–30.5%
Right shoulder height	1,45,790 (24.5)	24.2%–24.7%
Scapula tilt
Normal	3,43,942 (57.8)	57.6%–58.1%
Tilt to the left	1,49,954 (25.2)	25.0%–25.5%
Tilt to the right	1,01,161 (17.0)	16.8%–17.1%
Pelvic tilt
Normal	5,48,642 (92.2)	92.0%–92.3%
Tilt to the left	22,612 (3.8)	3.7%–3.9%
Tilt to the right	23,803 (4.0)	3.9%–4.2%
Flat back
Normal	5,90,891 (99.3)	99.2%–99.4%
Abnormal	4,166 (0.7)	0.6%–0.8%
Thoracic kyphosis
Normal	5,78,990 (97.3)	97.2%–97.4%
Abnormal	16,067 (2.7)	2.6%–2.8%
Lumbar concave
Normal	4,58,193 (77.0)	76.8%–77.2%
Left concave	55,340 (9.3)	9.2%–9.4%
Right concave	81,524 (13.7)	13.5%–13.8%
Lumbar lordosis
Normal	5,92,081 (99.5)	99.4%–99.6%
Abnormal	2,976 (0.5)	0.4%–0.6%
Lumbar kyphosis
Normal	5,93,866 (99.8)	99.7%–99.9%
Abnormal	1,191 (0.2)	0.1%–0.3%
Angle of thoracic rotation
Normal (ATR: 0–5°)	5,86,131 (98.5)	98.4%–98.6%
Rotate to the left (ATR>5°)	2,380 (0.4)	0.3%–0.5%
Rotate to the right (ATR>5°)	6,546 (1.1)	1.0%–1.2%
Angle of lumbar rotation
Normal (ATR: 0–5°)	5,82,560 (97.9)	97.8%–98.0%
Rotate to the left (ATR>5°)	9,520 (1.6)	1.5%–1.7%
Rotate to the right (ATR>5°)	2,977 (0.5)	0.4%–0.6%
Angle of thoracolumbar rotation
Normal (ATR: 0–5°)	5,92,676 (99.6)	99.5%–99.7%
Rotate to the left (ATR>5°)	1,190 (0.2)	0.1%–0.3%
Rotate to the right (ATR>5°)	1,191 (0.2)	0.1%–0.3%
Incorrect posturea
Normal	2,06,484 (34.7)	34.5%–35.0%
Abnormal	3,88,573 (65.3)	65.0%–65.5%
Referral for radiographyb
No	5,73,039 (96.3)	96.2%–96.4%
Yes	22,018 (3.7)	3.6%–3.8%

N, number; CI, confidence interval; ATR, angle of trunk rotation.

Incorrect posture was defined as participant who was screened out one or more to the following abnormal physical signs: high and low shoulder, scapula tilt, pelvic tilt, flat back, thoracic kyphosis, lumbar concave, lumbar lordosis, lumbar kyphosis, angle of thoracic rotation>5°, angle of lumbar rotation>5°, angle of thoracolumbar rotation>5°.

Referral for radiography: an angle of trunk (thoracic, lumbar or thoracolumbar) rotation of 5° was the recommended threshold for referral to radiography.

Prevalence of Incorrect Posture of Chinese Children and Adolescents Stratified by Gender

According to gender (as shown in Table 3), the prevalence of incorrect posture was significantly higher in girls than that in boys (76.0% versus 56.6%, χ = 24,534.72, p < 0.001), and girls had a 1.34 times higher prevalence of incorrect posture than boys. As for the prevalence of referral for radiography, girls accounted for a higher rate than boys (5.2% versus 2.4%, χ = 3,270.10, p < 0.001). Besides pelvic tilt and thoracic kyphosis, the rest of the abnormal signs were higher for girls than boys.

Table 3

Prevalence of Incorrect Posture Stratified by Gender (N = 595,057)

Variables	Gender		χ2	P
	Boy	Girl
Total	3,24,932 (54.6)	2,70,125 (45.4)
High and low shoulder			36,711.32	<0.001
Normal	1,80,987 (55.7)	87,521 (32.4)
Left shoulder height	88,707 (27.3)	91,302 (33.8)
Right shoulder height	55,238 (17.0)	91,302 (33.8)
Scapula tilt			16,528.11	<0.001
Normal	2,09,256 (64.4)	1,34,252 (49.7)
Tilt to the left	76,359 (23.5)	74,014 (27.4)
Tilt to the right	39,317 (12.1)	61,859 (22.9)
Pelvic tilt			8,221.85	<0.001
Normal	2,64,495 (81.4)	2,41,222 (89.3)
Tilt to the left	22,745 (7.0)	14,317 (5.3)
Tilt to the right	37,692 (11.6)	14,586 (5.4)
Flat back			1,013.62	<0.001
Normal	3,23,632 (99.6)	2,67,154 (98.9)
Abnormal	1,300 (0.4)	2,971 (1.1)
Thoracic kyphosis			456.12	<0.001
Normal	3,14,859 (96.9)	2,64,182 (97.8)
Abnormal	10,073 (3.1)	5,943 (2.2)
Lumbar concave			8,201.27	<0.001
Normal	2,64,495 (81.4)	1,93,680 (71.7)
Left concave	22,745 (7.0)	32,685 (12.1)
Right concave	37,692 (11.6)	43,760 (16.2)
Lumbar lordosis			120.80	<0.001
Normal	3,23,632 (99.6)	2,68,504 (99.4)
Abnormal	1,300 (0.4)	1,621 (0.6)
Lumbar kyphosis			60.05	<0.001
Normal	3,24,282 (99.8)	2,69,315 (99.7)
Abnormal	650 (0.2)	810 (0.3)
Angle of thoracic rotation			1,450.34	<0.001
Normal (ATR: 0–5°)	3,21,682 (99.0)	2,64,452 (97.9)
Rotate to the left (ATR>5°)	1,300 (0.4)	1,351 (0.5)
Rotate to the right (ATR>5°)	1,950 (0.6)	4,322 (1.6)
Angle of lumbar rotation			1,656.85	<0.001
Normal (ATR: 0–5°)	3,20,383 (98.6)	2,62,291 (97.1)
Rotate to the left (ATR>5°)	3,249 (1.0)	5,943 (2.2)
Rotate to the right (ATR>5°)	1,300 (0.4)	1,891 (0.7)
Angle of thoracolumbar rotation			514.32	<0.001
Normal (ATR: 0–5°)	3,23,957 (99.7)	2,68,234 (99.3)
Rotate to the left (ATR>5°)	325 (0.1)	810 (0.3)
Rotate to the right (ATR>5°)	650 (0.2)	1,081 (0.4)
Incorrect posturea			24,534.72	<0.001
Normal	1,41,020 (43.4)	64,830 (24.0)
Abnormal	1,83,912 (56.6)	2,05,295 (76.0)
Referral for radiographyb			3,270.10	<0.001
No	3,17,134 (97.6)	2,56,079 (94.8)
Yes	7,798 (2.4)	14,046 (5.2)

ATR, angle of trunk rotation.

Incorrect posture was defined as participant who was screened out one or more to the following abnormal physical signs: high and low shoulder, scapula tilt, pelvic tilt, flat back, thoracic kyphosis, lumbar concave, lumbar lordosis, lumbar kyphosis, angle of thoracic rotation>5°, angle of lumbar rotation>5°, angle of thoracolumbar rotation>5°.

Referral for radiography: an angle of trunk (thoracic, lumbar or thoracolumbar) rotation of 5° was the recommended threshold for referral to radiography.

Prevalence of Incorrect Posture of Chinese Children and Adolescents Stratified by Age

According to age (as shown in Table 4), the prevalence of incorrect posture was significantly higher in students aged 10–15 years and >15 years than in students aged <10 years (64.8% and 71.1% versus 41.3%, χ = 2,469.68, p < 0.001); students aged 10–15 years and >15 years had a 1.57 and 1.72 times higher prevalence of incorrect posture than students aged <10 years, respectively. Students aged 10–15 years and >15 years had a higher prevalence of referral for radiography than students aged <10 years (3.3% and 6.7% versus 0.5%, χ = 2,185.58, p < 0.001). Besides lumbar lordosis and lumbar kyphosis, the rest of the abnormal signs were higher for students aged 10–15 years and >15 years than students aged <10 years.

Table 4

Prevalence of Incorrect Posture Stratified by Age (N = 595,057)

Variables	Age (year)			χ2	P
	<10	10–15	>15
Total	5,355 (0.9)	5,18,890 (87.2)	70,812 (11.9)
High and low shoulder				2,906.49	<0.001
Normal	3,722 (69.5)	2,37,652 (45.8)	27,900 (39.4)
Left shoulder height	562 (10.5)	1,53,591 (29.6)	25,634 (36.2)
Right shoulder height	1,071 (20.0)	1,27,647 (24.6)	17,278 (24.4)
Scapula tilt				732.69	<0.001
Normal	3,925 (73.3)	3,00,437 (57.9)	39,513 (55.8)
Tilt to the left	702 (13.1)	1,30,241 (25.1)	19,261 (27.2)
Tilt to the right	728 (13.6)	88,212 (17.0)	12,038 (17.0)
Pelvic tilt				371.31	<0.001
Normal	5291 (98.8)	4,78,417 (92.2)	64,864 (91.6)
Tilt to the left	27 (0.5)	19,718 (3.8)	2,762 (3.9)
Tilt to the right	37 (0.7)	20,755 (4.0)	3,186 (4.5)
Flat back				343.53	<0.001
Normal	5,339 (99.7)	5,15,777 (99.4)	69,962 (98.8)
Abnormal	16 (0.3)	3,133 (0.6)	850 (1.2)
Thoracic kyphosis				133.89	<0.001
Normal	5312 (99.2)	5,04,361 (97.2)	69,183 (97.7)
Abnormal	43 (0.8)	14,529 (2.8)	1,629 (2.3)
Lumbar concave				1,588.28	<0.001
Normal	4,840 (90.4)	4,02,140 (77.5)	51,197 (72.3)
Left concave	220 (4.1)	46,700 (9.0)	8,497 (12.0)
Right concave	295 (5.5)	70,050 (13.5)	11,118 (15.7)
Lumbar lordosis				14.19	0.132
Normal	5,323 (99.4)	5,16,296 (99.5)	70,529 (99.6)
Abnormal	32 (0.6)	2,594 (0.5)	283 (0.4)
Lumbar kyphosis				3.04	0.218
Normal	5,350 (99.9)	5,17,852 (99.8)	70,670 (99.8)
Abnormal	5 (0.1)	1,038 (0.2)	142 (0.2)
Angle of thoracic rotation				825.29	<0.001
Normal (ATR: 0–5°)	5,350 (99.9)	5,12,144 (98.7)	68,971 (97.4)
Rotate to the left (ATR>5°)	0 (0.0)	2,076 (0.4)	496 (0.7)
Rotate to the right (ATR>5°)	5 (0.1)	4,670 (0.9)	1,345 (1.9)
Angle of lumbar rotation				1,461.42	<0.001
Normal (ATR: 0–5°)	5,339 (99.7)	5,09,550 (98.2)	68,050 (96.1)
Rotate to the left (ATR>5°)	11 (0.2)	7,264 (1.4)	2,124 (3.0)
Rotate to the right (ATR>5°)	5 (0.1)	2,076 (0.4)	638 (0.9)
Angle of thoracolumbar rotation				240.36	<0.001
Normal (ATR: 0–5°)	5,350 (99.9)	5,16,814 (99.6)	70,246 (99.2)
Rotate to the left (ATR>5°)	0 (0.0)	1,036 (0.2)	282 (0.4)
Rotate to the right (ATR>5°)	5 (0.1)	1,040 (0.2)	284 (0.4)
Incorrect posturea				2,469.68	<0.001
Normal	3,143 (58.7)	1,82,649 (35.2)	20,465 (28.9)
Abnormal	2,212 (41.3)	3,36,241 (64.8)	50,347 (71.1)
Referral for radiographyb				2,185.58	<0.001
No	5,328 (99.5)	5,01,767 (96.7)	66,068 (93.3)
Yes	27 (0.5)	17,123 (3.3)	4,744 (6.7)

Abbreviations: ATR, angle of trunk rotation.

The alpha level for paired comparison was set at p = 0.0167 after Bonferroni correction.

Incorrect posture was defined as participant who was screened out one or more to the following abnormal physical signs: high and low shoulder, scapula tilt, pelvic tilt, flat back, thoracic kyphosis, lumbar concave, lumbar lordosis, lumbar kyphosis, angle of thoracic rotation>5°, angle of lumbar rotation>5°, angle of thoracolumbar rotation>5°.

Referral for radiography: an angle of trunk (thoracic, lumbar or thoracolumbar) rotation of 5° was the recommended threshold for referral to radiography.

Discussion

Higher incidence of incorrect posture in children and adolescents may have negative impact on the whole metabolism, including the cardiopulmonary function and skeletal system (Yu et al., 2002, Macialczykpaprocka et al., 2017). Our large-scale population-based study found that Chinese children and adolescents had serious body posture problems, and around 3.7% of the children and adolescents were referred for radiography; girls and senior students were especially at high risk. These findings help to describe the epidemiological characteristics of incorrect posture in Chinese children, and provide evidence for identifying high-risk groups and develop targeted interventions.

Our results illustrated that the overall prevalence of incorrect posture among children and adolescents in China was 65.3%, and around 3.7% children and adolescents were referred for radiography, which was similar to previous research findings (Luk et al., 2010, Lee et al., 2010). In Western countries, most of the primary and secondary school students have a certain degree of incorrect posture, and only 18%–50% children and adolescents have a correct body posture (Kratenová et al., 2007, Jakub, 2011). The findings of our study also showed similar epidemic characteristics with previous studies; the high and low shoulders and scapula tilt account for a high proportion, indicating that the physical posture of children and adolescents in China has become more serious, which needs to be seriously considered by education departments and related public health organizations.

Furthermore, our group comparison results showed that the prevalence of incorrect posture in girls was much higher than that in boys, and 5.2% girls were referred for radiography, which was 2.2 times higher than that in boys. Our findings were consistent with the studies of Alen (Alen ćirić, 2015) and Penha (Penha et al., 2017), but a study conducted in northern China showed that boys had a higher prevalence of incorrect posture than girls (Li, 2018). This variation in results may derive from the different sampling areas and age structures. Owing to the earlier physiological development, girls are more likely to extend their neck and chest to reduce the change of appearance image (Cash and Pruzinsky, 1992, Feingold and Mazzella, 1998). Besides, girls may show less physical activity intensity than boys, which tends to lead to lack of muscle strength, making girls more difficult to control body posture than boys (Klassonheggebo and Anderssen, 2003). Therefore, based on these possible reasons, girls may be a high-risk group with incorrect posture.

Previous studies have shown that with age, body posture problems of children and adolescents would become more serious (Ludwig et al., 2016). Our results also found that students aged 10–15 years and aged >15 years had more serious body posture problems than students aged <10 years. The reason for the rising trend of incorrect posture rate with aging may be related to the increase of hormone secretion and the significant changes of physical development and mental status in adolescence (Richmond and Rogol, 2016, Hackney et al., 2016). In addition, with the rapid growth of adolescents in puberty, their biomechanical condition may change during this period (Stokes, 2007). Many adolescents are attending school and sitting for a long time, which may lead to muscular imbalance of their trunk muscles (Falk and Bradl, 2013). Therefore, adolescence may be a period of high incidence of incorrect posture.

In our large-scale school screening program conducted in south China, apart from the objective criteria (angle of trunk rotation of thoracic, lumbar, or thoracolumbar), a student would also be examined when there were significant signs of body appearances, including uneven shoulder height, scapular prominence, hip and pelvic obliquity, and so on (Hengwei et al., 2016, Lee et al., 2010). To our best knowledge, this is the first population-based study to report the prevalence of incorrect posture of children and adolescents. Our findings can provide essential information to better understand the epidemiology of incorrect posture, which can be an important reason for progression to adolescent idiopathic scoliosis, and to help policymakers develop appropriate program through rational planning. Our data showed that there is a high prevalence of incorrect posture among Chinese children and adolescents. As girls and senior students are found to account for a higher rate, it is of great importance to screen those students.

Limitations of the Study

The present study has several limitations that are worth noting. First, due to the cross-sectional nature of the data, it is difficult to make causal inferences. Second, our study sample included only school students and did not include children and adolescents who had dropped out of school or were not present in school on the day the screening was conducted. Third, although gender and age have been reported to be important factors in incorrect posture (Ludwig et al., 2016), other relevant influencing factors (e.g., genetics, hormone, and nutritional status) (Weinstein et al., 2008, Yang et al., 2009, Sousa et al., 2016) have not been investigated in this study. In addition, our study did not measure students' height, weight, and body fat, so we could not explore the association of these anthropometric data with incorrect posture.

Conclusion

Our population-based epidemiology evidence showed that Chinese children and adolescents have a significantly high prevalence of incorrect posture, and girls and older students may be an especially high-risk group. Appropriate prevention and intervention programs targeted for school students should be established to improve their physical health.

Methods

All methods can be found in the accompanying Transparent Methods supplemental file.