|Year : 2020 | Volume
| Issue : 2 | Page : 108-114
Relationship between age, gender and low back pain in patients referred for magnetic resonance imaging of lumbosacral spine at ahmadu bello university teaching hospital, Zaria
Usman Bello O, AF Oyewole, ND Chom
Department of Radiology, Faculty of Clinical Sciences, College of Medical Sciences, Ahmadu Bello University/A.B.U.T.H, Zaria, Nigeria
|Date of Submission||26-Nov-2019|
|Date of Decision||03-Jun-2020|
|Date of Acceptance||16-Jun-2020|
|Date of Web Publication||9-Oct-2020|
Dr. Usman Bello O
Department of Radiology, College of Medical Sciences, Ahmadu Bello University, Zaria
Source of Support: None, Conflict of Interest: None
Context: Low back pain (LBP) is a symptom of many lumbosacral spine abnormalities which are prevalent in all occupational groups in our environment. Its frequency and severity are significantly related to age and gender. Aims: To determine the relationship between age, gender and LBP in patients referred for magnetic resonance imaging (MRI) of lumbosacral spine. Settings and Design: A cross sectional study at Ahmadu Bello University Teaching Hospital, Zaria. Materials and Methods: The study was conducted within 4 years at the MRI suite of the Department of Radiology, on 200 patients who had LBP who had MRI scan. Statistical analysis used: Data from the questionnaires were sorted and entered into Microsoft Excel. Analysis was performed using the Statistical Package for Social Sciences Version 22.0. Results: There is male preponderance, with a male to female ratio of 1.6:1. The ages ranged from 11 to 80 years, with a mean of 47.8 + 1.4, and the peak incidence (55 [27.5%]) is in the fourth and fifth decades of life. A statistically significant association (χ2 = 33.9; P < 0.001) was also found between the severity of LBP and ageing. Majority of the patients (172 [86%]) had intervertebral disc prolapse/herniation, out of which 104 (60.5%) were males and 68 (39.5%) were females. Conclusion: Patients with lumbar disc prolapse had early age incidence with male preponderance. The incidence of lower level disc involvement was more, and there was no significant decadal difference in presentation, when both protruded and extruded types of disc prolapse were compared to age and gender.
Keywords: Age, gender, low back pain, lumbo-sacral spine, magnetic resonance imaging
|How to cite this article:|
Bello O U, Oyewole A F, Chom N D. Relationship between age, gender and low back pain in patients referred for magnetic resonance imaging of lumbosacral spine at ahmadu bello university teaching hospital, Zaria. Niger J Basic Clin Sci 2020;17:108-14
|How to cite this URL:|
Bello O U, Oyewole A F, Chom N D. Relationship between age, gender and low back pain in patients referred for magnetic resonance imaging of lumbosacral spine at ahmadu bello university teaching hospital, Zaria. Niger J Basic Clin Sci [serial online] 2020 [cited 2021 Mar 3];17:108-14. Available from: https://www.njbcs.net/text.asp?2020/17/2/108/297605
| Introduction|| |
Low back pain (LBP) has always been a common complaint amongst adults of both sexes in this environment cutting across all ages, professions and social and economic backgrounds. The term LBP, as defined by Anderson and used in most surveys of (LBP), is defined as pain limited to the region between the lower margins of the 12th rib and the gluteal folds.
In the United States, lower back pain is the second most common complaint encountered by primary care physicians after the common cold. Lower back pain affects nearly all Americans from time to time, especially those who are overweight, are sedentary or work in physically demanding jobs. LBP affects 70%–80% of the general population at some time in their lifetime. It is a leading cause of disability and activity limitation in persons between 35 and 40 years of age.
LBP is a well-recognised cause of morbidity in the industrialised world, where several studies have reported the occurrence of LBP in the general population and occupational settings.
Other reported risk factors of LBP include high body mass index (BMI), smoking, older age, being female and sedentary work. Occasionally, acute back pain is an indication of serious medical illness such as infection, malignancy or other systemic diseases.
Soft-tissue injury is commonly classified as 'acute' if it has been present for days to weeks. If the strain lasts longer than 3 months, it is referred to as 'chronic.' The severity of the pain ranges from mild to severe, depending on the degree of strain and resulting spasm of the muscles of the lower back. The nerves of the lumbar spine can be irritated by mechanical impingement or diseases any where along their paths from their roots at the spinal cord to the skin surface. The frequency and severity of LBP are also significantly related to sociodemographic factors such as age, gender, height, weight and BMI.
Initially, conventional radiography was the diagnostic imaging modality for evaluation of diseases of the lumbosacral spine. Radiographic projections were designed to demonstrate abnormal processes in the spinal canal, intervertebral foramina, disc spaces, vertebral bodies, posterior elements and facet joints. Radiography is commonly used as a diagnostic test for patients with acute back pain. Low cost and easy availability make plain radiography the most common spinal imaging test. During the acute back pain episode, 46% of patients had radiography, while 9% had computed tomography (CT) or magnetic resonance imaging (MRI).
The introduction of CT in 1972 and MRI in 1982 has improved the diagnostic capabilities by enabling location and characterisation of tumours, cysts and inflammatory diseases in the lower spine, aiding in early diagnosis and treatment.
MRI is a non-invasive direct multiplanar imaging method that uses radiofrequency waves and a powerful magnetic field to provide clear and detailed images of the lumbar spine.
LBP exists in epidemic proportions in the Western world and is on the increase there. The literature on its epidemiology from developed countries is accumulating. Data from the developing world are scanty, and little epidemiological data are available from Nigeria.
Therefore, research into the most effective strategies to prevent and manage LBP in Africa is warranted. Further research into the knowledge of associated sociodemographic factors, age and gender may also throw more light on the management of individual cases as well as in the design of preventive measures.
This study aimed at determining the relationship of age, gender and LBP in patients referred for MRI of lumbo-sacral spine at Ahmadu Bello University Teaching Hospital (ABUTH), Zaria. The lack of information on the prevalence of LBP in developing countries is, therefore, a significant shortcoming, particularly as it is predicted that the greatest increases in LBP prevalence in the next decade will be in developing nations, like Nigeria.
| Materials and Methods|| |
This is a prospective study carried out within a period of 4 years in the Department of Radiology, ABUTH, Zaria, Kaduna State, Nigeria, after approval was obtained from the Ethical Committee of the ABUTH.
Zaria is situated in the northwestern zone of Nigeria. The institution serves a population of about of 40 million people, which spread over the entire northwest, parts of northeast and north-central regions. It also serves parts of Niger, Cameroun and Chad republics.
The study population involved a purposive selection method, which is a simple random sampling technique. It is the selection of subjects with low back pain that the investigator believes are typical of the population to be studied.
- The study included all patients (Nigerians) that were referred to the Department of Radiology for MRI scan of the lumbo-sacral spine from the surgical clinics and wards of the ABUTH
- Patients referred from other hospitals with a history of LBP were also included in this study, for example, acute and chronic LBP and back injuries.
- Excluded from the study were those whose request for MRI was due to other reasons for LBP, for example, malignant tumours and infections
- Patients with spinal metallic implants that may cause errors in imaging were excluded. Individuals with ferromagnetic prosthesis and pregnant women were also excluded from the study.
A total of 200 patients were enrolled in the study having calculated the sample size using the formula by Araoye, where P = prevalent rate of LBP from a previous study. Where: P = prevalence rate of low back pain from a previous study, using 85% in the study done by Omokhodion. However, allowing for 10% attrition and concession to be made for non-response, the final sample size was rounded to 200.
Permanent magnet 0.2T 'open' MRI Unit (Magnetom Concerto Syngo MR 2004A, Siemens Erlangen, Germany), body coil, intravenous contrast medium (gadolinium-diethylene triamine pentaacetic acid), cannulas/needles and syringes for securing intravenous line, MRI films, laser printer, calibrated weighing scale and height-measuring stadiometer were used in this study.
Having ascertained the eligibility of the participants, the procedure was explained to them, and informed consent was obtained from patients, parents or guardians, as applicable.
Patients were then led to the changing room where they had to remove their clothes, one at a time, and wore examination gown. The participants were also instructed to remove all metallic objects including jewelleries, watches, hairpins and phones, aimed at averting missile injury and radiofrequency interference.
Patients were registered and weighed in kilograms using a calibrated scale and their height was measured in meters using a height-measuring stadiometer. It was necessary to weigh these patients as some of them required intravenous contrast medium (gadolinium) whose dose is normally calculated per body weight (0.2 mI/kg body weight).
All procedures were done under the close supervision of a consultant radiologist who further re-examined and vetted the images and sent a report to the patient's personal physician within a day for appropriate treatment, if any.
Method of data analysis
Data from the questionnaires were sorted and entered into Microsoft Excel. Analysis was performed using the Statistical Package for Social Sciences Version 22.0. (SPSS Inc, Chicago, lL, USA). The results were presented as frequency tables, means and percentages. Histograms, pie charts and bar charts were used where necessary to demonstrate trends in the variables.
Descriptive statistics of frequencies and percentages were used to describe the categorical variables, while the Chi-square contingency table technique was used to analyse the data. All tests of significance were two tailed, and P < 0.05 (95% confidence interval) were considered statistically significant.
| Results|| |
A total of 200 patients were included in this study; their ages ranged from 11 to 80 years, with a mean of 47.8 years and a standard deviation of 1.4.
One hundred and twenty-four (62%) patients were males, while 76 (38%) were females. The age and sex distribution is shown in [Table 1]. The age and sex pattern is demonstrated in [Figure 1] and [Figure 2]. The 200 participants studied were divided into seven groups according to their age as follows: (1) 11–20, (2) 21–30, (3) 31–40, (4) 41–50, (5) 51–60, (6) 61–70 and (7) 71–80 years, and the number of participants in each of these groups was 6, 14, 37, 55, 55, 26 and 7, respectively.
|Table 1: Distribution of the study population based on age group and gender|
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|Figure 1: Bar chart showing age distribution of patients with low back pain|
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|Figure 2: Bar chart showing age and sex distribution of patients with low back pain: χ2 = 11.5 P < 0.001|
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The peak incidence was in the fourth and fifth decades of life, with same number of patients (55 [27.5%]). These two groups were dominated by males. The prevalence of LBP was statistically significantly associated with age, or ageing (χ2 = 93.2; P < 0.0001).
The highest number of males (38 [19%]) and females (25 [12.5%]) was found in the 51–60 and 31–40 years' age groups, respectively. The least incidence (6 [3%]) was seen in the 11–20 years' age group.
Overall, there were more males (124 [62%]) than females (76 [38%]) that participated in this study. There was a statistically significant gender difference (χ2 = 11.5; P < 0.001), with a male-to-female ratio of 1.6:1 [Table 1] and [Figure 2]. In all the age groups, males were more in number except in the 31–40 years' age group where female dominance was noticed.
[Table 2] and [Table 3] show demographic factors in relation to the intensity of LBP. These demographic factors include age and gender as shown in [Table 2] and [Table 3], respectively.
|Table 2: Demographic factor (age) and intensity of patients' low back pain|
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|Table 3: Demographic factor (gender) and intensity of patients' low back pain|
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The severity of LBP was classified as mild, moderate or severe using the method described by Birabi et al. (LBP without radiation to the knee = mild; LBP radiating above the knee = moderate and LBP radiating below the knee = severe). Most of the patients (81 [40.5%]) had severe LBP, while 47 (23.5%) had mild LBP. In addition, most males (54 [43.5%]) had severe LBP, whereas most females (31 [40.7%]) had moderate LBP. The pattern of gender distribution and the severity of LBP are shown in [Figure 3].
|Figure 3: Bar chart showing gender distribution and severity of low back pain|
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A statistically significant association was found between the age and severity of LBP (χ2 = 33.9; P < 0.001), but this was not demonstrated with gender difference (χ2 = 1.5; P < 0.465).
The distribution of age and sex versus type of intervertebral disc prolapse is shown in [Table 4] where 104 (60.5%) of the 172 patients with disc prolapse were males and 68 (39.5%) were females. Among the males, disc bulging and protrusion were most common in the 51–60 years' age group, with both having 3 and 32 patients, respectively [Figure 4] and [Figure 5]. However, among the females, disc bulging and protrusion were more common in the 31–40 years' age group, with 2 and 19 patients, respectively. Disc extrusion was seen in six male and three female patients.
|Figure 4: Sagittal T2-weighted magnetic resonance imaging of the lumbosacral spine showing multiple levels of interver tebral disc dehydration and prolapse, and straightened lumbar lordosis|
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|Figure 5: Parasagittal T2-weighted magnetic resonance imaging of the lumbosacral spine showing multiple-level intervertebral disc dehydration and prolapse with compression of the nerve root in the exit foramina|
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[Table 5] shows gender distribution of the compression of the spinal canal by the disc prolapse seen in the 172 patients. Thecal sac, spinal cord and cauda equina were compressed in 159 (92.4%), 4 (2.3%) and 72 (41.8%) patients, respectively, with male dominance in all of them. Compressions of multiple structures were seen in 64 (37%) patients.
|Table 5: Compression of the spinal canal contents by the disc prolapse versus gender seen in the 172 patients|
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| Discussion|| |
LBP affects 70% to 80% of the general population at some time in their lives, and is a leading cause of disability and activity limitation in persons between 35 and 40 years of age.
MRI scanning of the lumbosacral spine has now gained broad acceptance as a highly accurate neuro-diagnostic technique, greatly altering the approach to diagnostic evaluation of patients with LBP.
LBP was, however, significantly more prevalent among females in a previous study with a female:male ratio of 2:1. Another study showed no major or significant gender differences.
In all the age groups, males were more in number except in the 31–40 years' age group where female dominance was noticed, and this is consistent with reports that female gender increases the risk of LBP. This is due to some female involvement in physically demanding activities such as farming in addition to the stress of childbearing.
Majority of the patients in this study were thus in the fourth and fifth decades (111 [55.0%]), closely followed by third decade with 37 (18.5%) followed by the sixth decade with 26 (13.0%). A result from the current study thus agrees with the study by Prasad et al., in which the highest percentage of patients, 89.4%, were between the ages of 21 and 60 years. This may be because people between 21 and 60 years are involved in physically demanding outdoor activities and are exposed to continuous trivial trauma to spine. The drop in LBP prevalence among patients over 60 years in this study probably reflects the low life expectancy in the study area and therefore small elderly population. They are also less likely to be involved in strenuous activities that may excite LBP above the age of 60 years.
Age was significantly associated with the prevalence of LBP (χ2 = 93.2; P < 0.0001) in this study with steady increase in the prevalence of LBP from 11 to 60 years in keeping with the study by Fabunmi et al. that showed increased prevalence with age.
The increasing prevalence of LBP with age appears more plausible, considering the prevalence of osteoarthritis, disc degeneration, osteoporosis and spinal stenosis in older populations, all of which may cause LBP. It has also been postulated that once back pain occurs, it is likely to be ongoing, so the increasing prevalence with age is not surprising. However, opinions on the association of age with LBP are diverse.
The increase in the prevalence of LBP with age in the present study may not be unconnected with the belief that the susceptibility to chronic diseases increases with age; this increase is a reflection of both physiological changes and cumulative environmental (occupation) and genetic risk factor exposure. The same assertion was reported by Charlotte and Stuart.
The statistically significant association (χ2 = 33.9; P < 0.001) found between the severity of LBP and age in this study corroborates with some of the findings of Stranjalis et al., where the frequency and severity of LBP were significantly related to sociodemographic factors such as age and gender.
Contrary to the findings from previous studies, gender (P < 0.465), in the current study, was not statistically significantly associated with the severity of LBP. However, differences in the characteristics of the sample populations in both studies would have been responsible for this. Gender, however, presented a significant association with the prevalence of LBP independently as previously highlighted above.
The severity of LBP in this study could be attributed to the degenerative effect of ageing.
Women are biologically predisposed to LBP due to risk factors such as pregnancy, young maternal age at first birth, duration of oral contraceptive use and use of oestrogens during menopause, all of which result in hormonal changes responsible for a global laxity in the muscles and ligaments of the back, compromising the stability of the spine. The combination of farming and other household work by females is capable of causing LBP. Lumbosacral lordosis is influenced by various parameters, including age, gender, pelvic bend and thoracic curvature, among others. Its angle was found to increase with age, with no differences between men and women, and has been further correlated to intervertebral stress distribution. Akano also found degenerative process of ageing termed spondylosis as the most common cause of the LBP. The peak age incidence in the current study is comparable with that of Weber's study, which showed the highest incidence in the age range of 30–50 years. This might be because people between 30 and 60 years of age are more involved in outdoor activities and are exposed to continuous trivial trauma to spine.
Majority of the patients (172 [86%]) in the present study had intervertebral disc prolapse/herniation, out of which 104 (60.5%) were males and 68 (39.5%) were females, with a male-to-female ratio of 1.5:1. This male preponderance is the usual presentation in lumbar disc prolapse.
When age and sex were taken into account, males presented a decade earlier as compared to females in the protrusion type of disc herniation; this is at variance with findings by Prasad et al. There was, however, no decadal difference in presentation among the gender groups when considering extrusion type of disc herniation seen in six males and three females in the current study.
Prasad et al. reportedincrease in the incidence of multiple-level disc prolapse/herniation associated with increase in age to be 26.7%, in contrast to the present study where the incidence was higher at 84.3%.
Thecal sac, spinal cord and cauda equina were compressed in 159 (92.4%), 4 (2.3%) and 72 (41.8%) patients, respectively, with preponderance of males. Compression of multiple structures was seen in 64 (37%) patients in this study, resulting from narrowing of the spinal canal. Tuite et al. noted that lumbar canal diameters from 10 to 12 mm may be associated with the characteristic syndrome associated with lumbar stenosis termed 'neurogenic intermittent claudication'.
MRI application to the management of LBP patients will thus be of significant benefit to both the patient and the managing physician.
Limitations of the study
The study limitations were small study population due to high cost of the MRI scan. Wilful misstatements from patients were also a setback. However, this effect was reduced to the barest minimum by repeating the questions thrice.
| Conclusion|| |
This study indicates that LBP is a common health problem among the general population studied. Patients with lumbar disc prolapse had early age incidence with a male preponderance. The incidence of lower level disc involvement was more in the present series, and no significant decadal difference in presentation was found when both protruded and extruded types of disc prolapse were compared to age and gender of the patients.
A similar study in other geopolitical zones of the country is also recommended as age and gender were known to affect the prevalence and severity of LBP and possibly with the use of higher Tesla MRI system.
Patient education on the risk of LBP and proper body mechanics should be done by public healthcare physicians, on the necessary precaution to adopt based on age or gender.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]