Young people’s low back pain and awareness of postural habits: A cross-sectional study

1.Introduction

Young people tend to spend most of their days sitting down while carrying out sedentary activities [1, 2, 3], combining long periods in this position during their classes with the time they spend at home using the computer (or other electronic devices) and watching television [1, 2, 4, 5]. By adopting inappropriate positions for these activities, some postural habits such as tilting the head and/or trunk forward, overload the muscles in these regions and other structures of the backbone [6, 7, 8, 9, 10, 11]. In addition, when sitting down the lower limbs remain flexed, which promotes a reduction in the flexibility of the thigh muscles, quadriceps and the lower back extension, provoking compensation in other regions [11]. The habit of slump sitting, very common among young people when watching TV and using the computer, causes a reduction in lumbar lordosis or even kyphosis in this region, increased kyphosis in the thoracic region, with great deformation and impact on the tissues in these regions [5, 12]. The habit of lying in a prone position in bed and when using the computer [4] the asymmetrical use of backpacks [13, 14] and other inappropriate postural habits promote musculoskeletal alterations which overload the backbone and are associated with pain [3, 13, 15], and the association between postural habits and low back pain (LBP) has often been reported [4].

LBP was identified as the most prevalent source of musculoskeletal complaint in young people and can be considered a public health issue [4]; the presence of back pain in 17-year olds is similar to that in adults [16], and may be associated with the use of medication, going to the doctor, school absenteeism, and reductions in the levels of physical activity and health quality [7, 9, 12]. However, the extension of the responsibility of the inappropriate positions adopted in the development of LBP is not known, since it has a multifactorial nature [17, 18, 19]. There are few studies investigating the role of postural habits in the LBP of adolescents [4, 20], and the evaluation of postures adopted during daily activities is important to understand the origin of the symptoms [4, 21, 22] and contribute to the implementation of preventative measures [4]. The acquisition of proper body behaviour and postural habits must be modelled while still in adolescence, reducing the risk of postural changes and/or symptoms in adulthood [20, 23].

For this study it was necessary to construct and previously validate a self-perception questionnaire concerning body posture, since the instruments used in other surveys did not correspond to the perceptions of young people with respect to their habits (a pilot study had been previously carried out). This study aimed to investigate the prevalence of low back pain and its associations with postural habits as perceived by young people between 15 and 18 years of age.

2.Methods

3.Results

Of the 679 young people under evaluation, 37.26% were boys and 62.74% were girls. The girls had already started menstruating and most of them had their menarche when they were 12 years old (27.5%); 93.5% of the participants did not smoke and 81.0% did not work. Regarding the prevalence of LBP in this group, the current prevalence point was 27.2%, in the three-month period it was 57.7% and 73.9% throughout life. Boys and girls presented values that were significantly different for the current prevalence (p= 0.005), for the three-month period (p< 0.001) and throughout life (p< 0.001), and a larger number of girls presented LBP at the three moments (Fig. 1).

Figure 1.

Low back pain prevalence in young male and female people (%).

The participants did not present significant differences between genders regarding most of the pain characteristics (age of onset, frequency, intensity, time of retreat of the most intense LBP, seeing a doctor and seeking treatment). The variable: presence of pain in another region simultaneously with the LBP of highest frequency was only observed in girls (p< 0.001). The remaining characteristics of the group as related to LBP are described in Table 1.

Differences were observed when comparing gender in relation to the perception of postural habits, and the girls usually showed more awareness of poor postural habits than the boys, except for the lying down posture and regarding disciplining by teachers related to student body positions in the classroom. Boys and girls showed significant differences with respect to their perceptions of posture in a seated position (p< 0.001), on foot (p< 0.001) and in movement (p= 0.006) (Table 2).

For boys (Table 4), the postural habits of turning the body, reducing lumbar lordosis or kyphosis in this region when sitting in the classroom, in the same position, rotating the body, not placing the feet on the ground and watching TV or using the computer or other similar devices in an inappropriate posture at home, are all associated with LBP. Disciplining by teachers who allow movement in the classroom was also significant regarding LBP. On the other hand, proper thoracic support in the classroom, lying in a prone position in bed and sitting in an appropriate position to watch TV or use the computer or similar device, were significantly associated with the absence of LBP.

For girls (Table 4), postural habits associated with LBP were to tilt and rotate the body, cross the legs when sitting in the classroom; and at home, tilting and rotating the body, reducing lumbar lordosis or kyphosis in this region, placing the feet on the floor when sitting, distributing the body weight asymmetrically on the legs when standing, inappropriate posture when lying down or sitting to watch TV or use the computer or other similar devices. Disciplining by teachers who allow student movement in the classroom was also associated with the complaint. On the other hand, the habits of sitting with proper thoracic support in the classroom and at home, with the feet placed on the floor in the classroom, and an appropriate position to watch TV or use the computer or other similar devices, and suitable support on both legs when standing at home, were associated with the absence of LBP.

The analyses of the association between postural habits and LBP were carried out at three different moments (at present, in a three-month period and throughout life) and the LBP throughout life was seen to have more associations for both boys and girls.

4.Discussion

This was a cross sectional and retrospective study that calculated the values for the prevalence of LBP, 27.2% at the present moment (moment of the survey), 57.7% in a three-month period (last three months), and 73.9% throughout life, in 679 young people (15 to 18 years old), seeking to identify the associations with postural habits noticed by the participants. A study with a group of 546 Danish youngsters, representing an age group similar to that used in this study, Skoffer et al. [27] found 51.3% prevalence of LBP in the last three months and 64.8% throughout life; Smith et al. [16] observed that 49.5% of 1126 17-year old Aus-

tralian youngsters presented LBP. The values found in the studies were different, but it is important to consider that the methodologies, age groups, sample size and operational definition of the pain were different. However, the high prevalence values strengthen the concern with this health problem, since they mean that at least 1 of each 2 youngsters in the different studies (Brazil, Denmark and Australia) aged up to 17/18 years old, had already complained of LBP at some point in life.

The girls presented significantly higher values for LBP prevalence and this difference in gender was also observed in other studies [4, 14, 24, 28]. Noll et al. [14] reported that the poor postures of girls when carrying out daily activities, including sleeping, sitting to write or use the computer, watching TV, reading or studying in bed, helped to explain these complaints. In this study, in general the girls presented some awareness of inappropriate postural habits, differently from the boys, and significant differences were observed considering the habits of sitting, standing and moving around the classroom and when using the computer at home. However, poor postural habits adopted by most of the boys were also observed. Therefore, other factors have been suggested to explain the higher prevalence of LBP in girls, such as hormonal alterations due to sexual maturation prior to the boys, and the different kinds of hormones released [1, 29]. Regarding social and emotional aspects, girls are more motivated to show their feelings, to notice and express their complaints more often [28, 30]; considering behavioural habits, the girls present lower levels of physical activity and spend more time in sedentary activities [1, 14] and in poor positions that justify their complaints of pain [14].

The differences in the awareness of postural habits adopted and in the prevalence of LBP found in this study, when comparing boys and girls, reinforce the idea that groups of pain rather than the pain itself should be studied, and approached with specific measures for each gender. Confirming these findings, Straker et al. [31] reported the associations between pain and young people’s postural habits, and emphasized the importance of analysing these themes in clusters: boys and girls, as carried out in this study.

Although significant differences in habits have been noticed when comparing genders, the posture when sitting with reduction in lumbar lordoses or kyphosis in this region, turning and tilting of the body and not placing the feet on the floor in the classroom and at home, were all associated with LBP, while the habits of maintaining proper thoracic support, maintaining lumbar lordosis and placing the feet properly on the ground in the classroom and at home were associated with the absence of LBP for both genders.

Healthy postural habits are related to keeping the alignment of the backbone so that minimum tension is caused to this structure, with no waste of energy or discomfort [15, 32]. Young people who do not maintain suitable alignment or remain long periods in the same position have greater risks of feeling back pain due to the increase in mechanical load and tension [32, 33, 34]. For this reason, the position adopted by young people who sit for long periods in school has been investigated, since it tends to cause musculoskeletal disorders, such as trunk flexion and alterations in normal curves of the backbone, such as flattening or kyphosis in the lumbar region, causing overloads on the spinal discs, ligaments and muscles [3, 11, 12].

Proper placement of the feet on the floor (referred to by the girls) associated with pain seems to be incoherent, since this position tends to promote the adoption of a neutral posture [35]. In this case, feet support is believed to be accompanied by another frequent posture common to young people, that of slump sitting. While seated, they tend to lean the body backwards, supporting the thoracic region against the back of the chair and the sacrum on the seat, or even sitting with no thoracic support, altering the lumbar position (increasing lordosis or reducing the curvature) [4, 5, 12]. The participants of this study pointed out inappropriate sitting and lying down habits to watch TV or to use the computer, as being associated with LBP, while a good sitting posture was associated with those who did not present complaints.

In addition to the slump position, the use of computers and other electronic devices while sitting promotes biomechanical alterations such as cervical flexion and tension of cervical muscles [6, 7, 8, 10, 31, 36], trunk flexion and pelvic tilt, which originate complaints of discomfort and pain [10, 11, 22]. When using the lying down supine position with stretched legs, the psoas muscle becomes tense and increases the lumbar load [37], also, the head is leaning forward due to the cushion support which increases the stress on vertebral structures [38]; in the prone position (lying belly down) the lumbar region tends to be in hyperlordosis, also overloading the vertebrae [4].

Standing with more weight on one leg was associated with LBP, whereas standing with the weight distributed equally on both legs was associated with the absence of complaint. Although this is a posture frequently seen in clinical practice, no studies were found on the standing position with an asymmetrical distribution of the body weight on the two legs. This question of modifying the distribution of body weight on the lower limbs is assumed to have compensations in the upper regions, pelvis and backbone.

No associations were found between LBP and the posture adopted to sleep, however, the prone posture was associated with the absence of pain in boys. This data is different from literature findings in which this position is not advised for involving increases in lumbar lordosis [37] and vertebral rotation [39]. During sleep, when the body is in a neutral position, the intervertebral discs are hydrated and their elasticity restored, inappropriate posture might hamper this recovery [39] and result in LBP [40, 41].

The acquisition of inappropriate postural habits occurs during childhood, and it is in this phase that preventative measures of education and intervention are indicated [11, 20, 23]. The school seems to be the most suitable place to implement these programs and the participation of teachers is fundamental [20, 42]. Regarding disciplining from the teachers related to the students’ postural habits in the classroom, allowing and stimulating movements were associated with LBP. This is not in agreement with the literature, which advocates that sitting for shorter periods, standing up and moving around are measures to combat LBP. Therefore, teachers should promote and encourage these more dynamic habits [20]. The young people taking part in this study may have interpreted this question in an equivocal way, considering that inadequate postures, such as twisting the trunk to talk to a colleague or slump sitting, are permitted and not corrected by the teachers.

This study found no significant associations between LBP and the habit of carrying a backpack or lifting objects up from the floor. However, other studies observed that the use of backpacks asymmetrically was associated with LBP [13, 14, 27]. Regarding weight lifting, this is one of the activities most noted as responsible for LBP, and involves the object weight, the posture used and the time of this activity [41].

This study had some limitations such as the use of a self-reported questionnaires, which depended on interpretation, memory and self-knowledge, and for being a cross-sectional study, which did not allow the inference of causality. Future studies should explore awareness of postural habits involving a more thorough approach to the young people’s perception of their postural habits, emphasizing the sleeping position, distribution of body weight on one or another leg while standing, and the crossed legs position when sitting, due to few existing studies. The knowledge of factors associated with LBP makes it possible to adopt preventative and therapeutic measures related to the education and guidance of postures adopted for everyday activities. Longitudinal studies are also suggested which follow young people throughout their maturational period, analysing the interactions between the several bio-morphological and psychosocial variables related to their lifestyle.

5.Conclusions

The data produced by this study revealed that the 679 youngsters aged 15 to 18 years old reported a high prevalence of LBP, especially the girls. The participants with low back pain noticed some habits associated with their pain, such as rotating and tilting the body, maintaining the lumbar region with a reduction of lordosis or kyphosis (flexion), not placing their feet on the ground and crossing their legs when sitting in the classroom or at home, watching TV or using the computer sitting or lying down with a poor posture and distributing the body weight asymmetrically on the legs when standing.

Strategies for the prevention and rehabilitation of LBP in young people should be based on the education and guidance of postural habits adopted in daily activities.