Correlation between Chronic Low Back Pain and Anthropometric Indices in the Elderly (aged 60–69 years): A Cross-Sectional Study

doi:10.21203/rs.3.rs-4001919/v1

The purpose of this study was to determine relationships between chronic low back pain (CLBP) and anthropometric indices in the elderly.A total of 430 individuals with ages ranging from 60 to 69 years participated in this cross-sectional study.Anthropometric measurements, including height and weight; waist and hip circumference; and upper arm skinfold, scapular skinfold, and abdominal skinfold thicknesses were measured. Body mass index (BMI) and waist-to-hip ratio (WHR) were calculated.To evaluate functional aspects pertaining to subjects while living with CLBP, the Oswestry Disability Index (ODI) was used.Among the elderly, no statistically significant difference was found in height, body mass; BMI; chestand waist, hip circumference; WHR; upper arm skinfold, scapular skinfold, and abdominal skinfold thicknesses between the elderly with CLBP and those without CLBP. Mann–Whitney U-test revealed no statistically significant difference in BMI, WHR, and weight, chest circumference between the elderly with CLBP and those without CLBP.Spearman rank correlation analysis showed that CLBP of the elderly was not correlated with height, weight, BMI, and chest circumference.Among the elderly, the ODI score of CLBP was statistically positively correlated with abdominal skinfold thickness (r_s = 0.165, P = 0.037) and with WC (r_s = 0.200, P = 0.012). Abdominal obesity is significantly associated with functional status in the elderly (aged 60–69 years) with CLBP.

elderly

body mass index

waist-to-hip ratio

obesity

chronic low back pain.

Low back pain (LBP) is one of the most common musculoskeletal problems worldwide. Approximately 80% of individuals are affected by LBP at least once in their lifetime ^[1]. LBP is the main cause of working disability in individuals under 45 years of age, and this condition causes great harm to both family and society and results in economic losses ^[2]. LBP has become a serious socio-economic problem, therefore, a reasonable understanding of its risk factors is extremely important for the prevention and treatment of chronic LBP (CLBP).

Obesity has become a global social public health issue in the developed and developing countries. A recent study indicates that obesity is somewhat correlated with pain. Compared with individuals of normal weight, obese patients are more prone to musculoskeletal pain and physical disability ^[3]. To reduce the incidence and prevalence of CLBP, the relationship between obesity and CLBP was determined. This study analysed the correlation between CLBP and body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and skinfold thickness in the elderly (aged 60–69 years).

Research subjects

The project was reviewed and approved by the Medical Ethics Committee of the Third Affiliated Hospital of Zhejiang Chinese Medical University (approval number: ZSLL-KY-2019-005-01). According to the ethical rules of the institution, patients were free to interrupt their participation at any time. All participants were informed about the purpose of the study in a standardized way and provided written informed consent prior to study participation.

Cluster sampling was used to extract the research population during the investigation. First, all streets and villages (towns) in the Liandu District, Lishui City, Zhejiang Province, China, were coded, and a certain number of neighbourhood (village) committees was selected. All populations in the selected neighbourhood (village) committees that matched the investigation conditions were regarded as research objects. The field investigation process was uniformly deployed in accordance with National Physique Monitoring Center guidelines, and heads of each neighbourhood (village) committee were assisted in its publicity and organisation. Through the rigorous screening of people aged 60–69 years in the selected neighbourhood (village) committee, the number of research objects was determined to be 430. All eligible persons participated in the field investigation, and the response rate was 100%.

In this survey, the general definition of CLBP in international epidemiological studies was used as a criterion to define CLBP among those aged 60–69 years; this definition was pain or discomfort below the 12th rib and above the hip area, which may or may not be accompanied by pain in the legs, lasting longer than 12 weeks ^[4].

Screening requirements for the target population of the field investigation included: normal mentality, clear consciousness, and no obvious physical defects. Any one of the following circumstances could be considered a research object:

(1) Individuals with physical disabilities;

(2) Individuals with abnormal physical development (such as giantism or dwarfism);

(3) Individuals with acute illnesses or those who have suffered from acute or chronic diseases, such as diarrhoea and high fever, in the past two weeks and whose physical strength has not recovered;

(4) Individuals who have suffered from major trauma, such as fracture and dislocation, in the past six monthsor those with obvious physical limitation;

(5) Individuals who have suffered from severe diseases of the heart, kidney, liver, lung, or other major organs (such as heart disease, hypertension, hepatitis, nephritis, tuberculosis, asthma, and pneumonia) or those not suitable for sports as diagnosed by a clinician.

Anthropometric measurements

The anthropometric indices were measured in accordance with the “2010 China National Physical Fitness Monitoring Workbook.” The indices measured included height, weight, chest circumference, WC, hip circumference, upper arm skinfold thickness, scapular skinfold thickness, and abdominal skinfold thickness. The measuring equipment was uniformly distributed by State Sports Administration of China(SSAC), and the equipment was commissioned, installed, and verified by professional technicians before use.All items of equipment were calibrated by the technical supervision department, and all equipment was compliant with relevant national measurement test standards.

Themasses (in kilograms) of theparticipants were measuredusing a weighing scale, withthe participants wearing minimal clothing. The height(in metres) was measuredby a height meter with theparticipants barefootand standing erect.

As shown in Table 1, no statistical significance was found in height (P = 0.679), body weight (P = 0.857), BMI (P = 0.875), chest circumference (P = 0.811), WC (P = 0.430), hip circumference (P = 0.770), WHR (P = 0.319), upper arm skinfold thickness (P = 0.458), scapular skinfold thickness (P = 0.651), and abdominal skinfold thickness (P = 0.959) between elderly patients with CLBP and those without. As shown in Table 2, the Mann–Whitney U-test revealed no statistically significant difference in BMI (P = 0.888), WHR (P = 0.616), and WC (P = 0.373) between elderly patients with CLBP and those without.

Based on Spearman rank correlation analysis, the occurrence of CLBP in the elderly was not significantly correlated with height, weight, BMI, chest circumference, WC, hip circumference, WHR, upper arm skinfold thickness, scapular skinfold thickness, and abdominal skinfold thickness (Table 3).

Table 4 shows that binary logistic regression analysis was performed with CLBP as the dependent variable (assignment: without CLBP = 0, with CLBP = 1), and BMI, WHR, and WC were the independent variables. The results implied that BMI, WHR, and WC were not significantly associated with CLBP.

Table 5 displays that the ODI scores of elderly patients with CLBP were statistically negatively correlated with height (r_s = −0.161, P = 0.043). By contrast, the ODI scores of elderly patients with CLBP were statistically positively correlated with abdominal skinfold thickness (r_s = 0.165, P = 0.037). Finally, the ODI scores of elderly patients with CLBP were statistically positively correlated with WC (r_s = 0.200, P = 0.012).

Numerous studies have suggested a correlation between being overweight or obese and LBP ^[5]. The findings of the present study indicated an interaction effect between obesity and LBP. The possible mechanisms were identified as follows: first, obesity or being overweight can increase mechanical stress on the spine and shear force on the lumbar vertebra during physical activity. Second, obesity is associated with the generation of cytokines and acute phase reactants and the activation of inflammatory pathways, which can lead to systemic chronic inflammation ^[6] and LBP. Third, a stronger correlation between abdominal obesity and LBP was found compared with that between peripheral obesity and LBP ^[7]. Other studies have also confirmed that hypertension and dyslipidaemia are associated with CLBP ^{[8, 9]}, therefore, metabolic syndrome may be a pathological path for LBP in obese patients. Fourth, obesity is associated with the degeneration of lumbar intervertebral disc and structural changes in the vertebral end-plate; spinal activity decreases with weight gain, which may affect the nutritional supply to the intervertebral disc. Obese patients have higher levels of serum triglyceride and LDL cholesterol but lower levels of HDL cholesterol than patients of normal weight. Dyslipidaemia plays an important role in the development of atherosclerosis in obese patients, and abdominal aortic atherosclerosis is associated with the degeneration of the lumbar disc. Atherosclerosis leads to lumbar segmental artery stenosis or even obstruction so that the nutritional supply to the intervertebral disc is insufficient, which may lead to the degeneration of the intervertebral disc; it may also cause ischemic pain through pain-sensitive structures such as nerve roots, bones, or muscles, thereby causing spinal dysfunction, which alters the mechanical environment of the intervertebral disc and further aggravates its degeneration ^{[10, 11]}; however, patients with severedegeneration of the lumbar intervertebral disc are highly likely to have LBP ^[12]. Fifth, in terms of being overweight, obese, or with centripetal obesity, fat accumulates in the waist and abdomen, which significantly limits the range of motion of lumbar vertebra and leads to weakened muscle strength of the waist and abdomen. Furthermore, fat accumulation in this region breaks the balance of the muscle system and increases the mechanical load on the waist, which generates LBP. From a mechanical perspective, the change in lumbar curvature is also a compensatory posture in which the lumbar spine itself increases in stability. In terms of abdominal obesity, thecentre of mass of the body moves forward, and the distance from the lumbar centre of motion, namely, the lever arm of force, increases. To maintain the stability of the spine and reduce the lever arm of the force, back muscles are contracted so that the lumbar lordosis is enlarged and the pelvis is tilted forward. The abdomen is tilted forward for compensation. Simultaneously, the lumbar vertebra load increases and LBP is generated due to fatigue in the lumbodorsal muscles ^[13].

The results of this study showed no significant difference in the anthropometric indices between the elderly with CLBP and those without LBP. The occurrence of CLBP in the elderly was not significantly associated with height, weight, BMI, chest circumference, WC, hip circumference, WHR, upper arm skinfold thickness, scapular skinfold thickness, and abdominal skinfold thickness.

BMI, WC, and WHR are simple and practical anthropometric indices that reflect obesity, and they are widely used in clinical and epidemiological studies. Increased BMI, WC, and WHR are natural trends in the aging process. With the gradual decline in height and the formation of kyphosis, the vertical space of the abdominal cavity is reduced, which increases the WC. The results of this study showed no significant difference in BMI, WC, and WHR between the elderly with CLBP and those without LBP.

At present, the scientific evidence necessary to prove whether or not a direct or causal relationship exists between overweight or obesity and LBP is insufficient. Mirtz and Greene ^[5] performed a review and analysis by applying the keywords “obesity,” “low back pain,” “body mass index,” and “BMI” on the Medline search engine. Their results suggested that the causal link between obesity and LBP remains controversial, and literature support for the association between BMI and LBP is insufficient. Therefore, the relationship between being overweight or obese and the onset of LBP requires further research for clarification and confirmation.

Obesity has been found to be associated with functional decline. In recent years, studies show that the functional decline of obese patients may be ascribed to the adverse effect of obesity-related inflammatory environment, loss of age-related skeletal muscles, and muscle damage on body function ^[14]. Chen ^[15] and other researchers found that the test value of obesity indicators is closely related to the severity of dysfunction in the elderly. For elderly females, abdominal obesity indicators are closely related to dysfunction.

The results of this study showed that the ODI scores of elderly patients with CLBP were significantly negatively correlated with height but significantly positively correlated with abdominal skinfold thickness and positively correlated with the level of significance of WC. Thus, abdominal obesity in the elderly was closely related to dysfunction and activity limitation caused by CLBP.

A correlation between obesity and functional limitation was observed. Obesity leads to a decline in muscle strength; in particular, obesity weakens the muscle strength of the lower limbs in the elderly, which can result in functional limitation in the elderly ^[16]. Obesity can lead to abnormal gait, which causes limitations on physical activity.

Therefore, the rehabilitation of CLBP in the elderly can be combined with intervention against obesity. By effectively interfering with obesity in the elderly, particularly abdominal obesity, the body weight can be controlled, and WC can be reduced, which may be conducive to promotion of recovery of dysfunction in patients with CLBP.

CLBP,chronic low back pain; BMI,body mass index; WHR,waist-to-hip ratio; ODI,the Oswestry Disability Index; WC,waist circumference; LBP,low back pain; SSAC,State Sports Administration of China

Conflict of interest

None of the authors have relevant interests to disclose.

Submission statement

The manuscript has not been published and is not under consideration for publication elsewhere.

Authors' contributionStatement

Xiaodong Wang, Xinzheng Wang Fanyuan Jin,Dehong Wang conducted thefield investigation and Anthropometric measurements, collected and analyzed the data;Li Ma and Juntao Yan designedand supervised the study. Xiaodong Wang wrote the manuscript.

Ethical Approval Statement

The project was reviewed and approved by the Medical Ethics Committee of the Third Affiliated Hospital of Zhejiang Chinese Medical University (approval number: ZSLL-KY-2019-005-01). According to the ethical rules of the institution, patients were free to interrupt their participation at any time. All participants were informed about the purpose of the study in a standardized way and provided written informed consent prior to study participation.

Acknowledgements

The authors are grateful to all participants who took part in the study.

Funding

This study is funded by high Level Key Discipline Construction Project of Traditional Chinese Medicine by the State Administration of Traditional Chinese Medicine under Grant No.GJXK2023-85,Construction Project of Zhejiang Province Famous Traditional Chinese Medicine Teacher Studio under Grant No.2022-GYMSGZS-01.

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Table 1 Differences in anthropometric indices of various elderly groups

	Anthropometric indices
	Height (cm)	Weight (kg)	BMI (kg/m²)	Chest circumference (cm)^※	Waist circumference (cm)	Hip circumference (cm)	WHR^※	Upper arm skinfold thickness (mm)^※	Scapular skinfold thickness (mm)^※	Abdominal skin fold thickness (mm)^※
A	158.00 ± 8.22	58.96 ± 9.56	23.53 ± 2.71	88.50 (84.00–92.50)	83.24 ± 8.42	91.12 ± 5.72	0.91 (0.88–0.95)	12.00 (8.00–17.00)	15.00 (10.00–19.00)	21.00 (15.00–25.50)
B	158.34 ± 8.33	59.13 ± 9.70	23.49 ± 2.65	88.50 (85.00–93.00)	82.57 ± 8.60	90.95 ± 5.99	0.91 (0.87–0.95)	12.00 (8.00–16.00)	14.50 (11.00–18.00)	21.00 (16.00–25.00)
P value	0.679	0.857	0.875	0.811	0.430	0.770	0.319	0.458	0.651	0.959

Note:^※represents that this indicator is expressed by the median and interquartile range of this indicator A: with （chronic low back pain）CLBP B: without CLBP

Table 2 Distribution of （body mass index）BMI,（waist-to-hip ratio）WHR, and（waist circumference）WC levels in the elderly with and without （chronic low back pain）CLBP (N=430)

	BMI level			WC level			WHR level
	BMI<24	24 ≤BMI<28	BMI≥28	WC1	WC2	WC3	WHR1	WHR2
Without CLBP	159	97	15	121	111	38	197	74
With CLBP	95	54	10	81	54	24	112	47

Note: WC1: male <85 cm, or female <80 cm; WC2: male 85–95 cm, or female 80–90 cm; WC3: male ≥95, or female ≥90 cm. WHR1: male WHR <0.90, or female WHR <0.85; WHR2: Male WHR ≥0.90, or female WHR ≥0.85.

Table 3 Correlation coefficient between the value of anthropometric indices of the elderly and （chronic low back pain）CLBP (r_s)

	Height	Weight	BMI	Chest circumference	Waist circumference	Hip circumference	WHR	Upper arm skinfold thickness	Scapular skinfold thickness	Abdominal skin fold thickness
CLBP	0.008	0.004	0.005	0.012	−0.029	0.004	－0.048	－0.036	－0.022	0.003
P value	0.877	0.929	0.926	0.811	0.546	0.939	0.319	0.458	0.651	0.959

Note: CLBP: assignment Yes = 1, No = 1.

Table 4 Logistic regression analysis of the relationship between (chronic low back pain)CLBP and (body mass index)BMI, (waist-to-hip ratio)WHR, and (waist circumference)WC in the elderly

	B	SE	Wald	Sig	Exp(B)	95%CI
BMI	0.149	0.228	0.426	0.514	1.160	0.743–1.812
WHR	−0.166	0.211	0.623	0.430	0.847	0.560–1.280
WC	−0.062	0.261	0.057	0.812	0.940	0.563–1.568
Constant	0.363	0.407	0.796	0.372	0.696

No competing interests reported.

Correlation between Chronic Low Back Pain and Anthropometric Indices in the Elderly (aged 60–69 years): A Cross-Sectional Study

Status:

Version 1

Abstract

Introduction

Methods

Research subjects

Anthropometric measurements

Results

Discussion

Abbreviations

Declarations

References

Tables

Additional Declarations

Status:

Version 1