Elsevier

The Spine Journal

Volume 8, Issue 5, September–October 2008, Pages 732-740
The Spine Journal

Clinical Study
Factors associated with lumbar intervertebral disc degeneration in the elderly

https://doi.org/10.1016/j.spinee.2007.07.392Get rights and content

Abstract

Background context

Lumbar intervertebral disc degeneration (DD) precedes degenerative diseases of the lumbar spine. Various factors in addition to normal aging are reported to be associated with DD, and recently atherosclerosis and risk factors for cardiovascular diseases (cardiovascular risk factors) have received much attention; however, the links between these risk factors and DD are unclear.

Purpose

By correlating magnetic resonance images (MRI) with suspected degenerative disc risk factors such as obesity, cardiovascular risk factors, and atherosclerosis, we hope to clarify the factors associated with DD.

Study design/setting

An observational study.

Patient sample

Two hundred seventy adults (51–86 years old) who participated in a health promotion program.

Outcome measures

DD evaluated based on the signal intensity of MR T2-weighted mid-sagittal images of the lumbar spine.

Methods

Age, gender, body mass index (BMI), low-density lipoprotein cholesterol (LDLc), triglyceride (TG), glycosylated hemoglobin (HbA1c), brachial-ankle pulse wave velocity (baPWV) as an index of atherosclerosis, osteo-sono-assessment index (OSI) calculated from quantitative ultrasound assessment of the calcaneus as an index of bone mineral density (BMD), history of low back pain (LBP), smoking and drinking habits, and physical loading related to occupations and sports were assessed. The univariate relationships between DD and the variables were evaluated, and finally, odds ratios (OR) and 95% confidence intervals (CI) for the associations of each factor with DD were calculated using logistic regression at each disc level.

Results

Aging correlated significantly with DD of L1/2 (OR, 2.14), L2/3 (OR, 3.56), L3/4 (OR, 2.84), and L4/5 (OR, 3.05); high BMI, with L2/3 (OR, 2.98), L3/4 (OR, 3.58), L4/5 (OR, 2.32), and L5/S1 (OR, 3.34); high LDLc, with L4/5 (OR, 2.65); occupational lifting, with L1/2 (OR, 4.25); and sports activities, with L5/S1 (OR, 3.36).

Conclusions

Aging, high BMI, high LDLc, occupational lifting, and sports activities are associated with DD. The results of this study raise our index of suspicion that cardiovascular risk factors and particular physical loading may contribute to DD; however additional studies are required to further investigate associations between DD and these factors.

Introduction

Lumbar intervertebral discs degenerate with normal aging [1], [2], [3], [4]. One study using magnetic resonance imaging (MRI) on healthy women reported about 30% of the subjects in their twenties had lumbar intervertebral disc degeneration (DD), whereas about 90% of the subjects in their seventies had DD [4]. Nevertheless, DD also precedes lumbar degenerative diseases, such as lumbar disc herniation and lumbar spinal canal stenosis; therefore, various studies aiming to identify risk factors for DD have been completed. The importance of heredity has become increasingly clear after the twin studies of Battie et al. [1], [5] and Sambrook et al. [6]. It is reported that individuals with specific gene polymorphisms might develop DD earlier than individuals without these genetic variants [7], [8], [9]. In addition, acquired factors, including obesity [3], [10], [11], diabetes mellitus [12], [13], smoking [12], [14], [15], physical loading related to occupations and sports [5], [16], [17], [18], [19], and bone mineral density (BMD) [3], [20], [21], have been associated with DD.

In industrialized nations, the human life span has been extended because of medical advances and improvements in eating habits; therefore, we are concerned that the number of patients who have lumbar degenerative diseases will increase, and thereby medical expenses also. Accordingly, we need to clarify which acquired factors promote DD so as to establish preventive measures against DD.

Recently, suspicions have arisen that atherosclerosis and occlusion of the abdominal aorta and the lumbosacral arteries result in insufficient blood flow and nutrition for the lumbar intervertebral discs and, consequently, might contribute to DD [2], [22], [23], [24]. Kauppila et al. examined and confirmed this association between DD and atherosclerosis using autopsies, radiographs, and MR aortographs [2], [22], [23]. It is well known that atherosclerosis is accelerated by some factors which are known as cardiovascular risk factors. Interestingly, obesity, diabetes mellitus, and smoking are not only suspected risk factors for DD, but are also cardiovascular risk factors. Furthermore, obesity and smoking is highly correlated with lifestyle, and type 2 diabetes can be triggered by overeating or lack of exercise in people predisposed to type 2 diabetes by specific hereditary factors. Jhawar et al. noted this, and prospectively and longitudinally have examined the associations between lumbar disc herniation and cardiovascular risk factors in nurses [12]. They found that lumbar disc herniation was associated with diabetes, high cholesterol, hypertension, smoking, and a myocardial infarction before age 60. If an association between atherosclerosis, cardiovascular risk factors, and DD is conclusively shown, this suggests that behaviors that help prevent atherosclerosis and cardiovascular diseases, which have only a weak association with orthopedic diseases, by early improvements in lifestyle, would reduce the frequency not only of cardiovascular diseases but also of DD and lumbar degenerative diseases as well. This could lead to the establishment of preventive measures against DD and lumbar degenerative diseases.

Consequently, we constructed this observational study to clarify the associations between DD, evaluated by MRI, and suspected risk factors for DD including atherosclerosis and cardiovascular risk factors.

Section snippets

Participants

In 2002 and 2003, we publicly recruited adults over 50 years of age to participate in a health promotion program by advertising in local newspapers in three municipalities (Tsukuba City with 190,000 inhabitants, Ogano Town with 12,500, and Taiyo Village with 11,000). The program included light weight– and endurance-training for about 1 year and physical examinations before and after the exercise program. The main purposes of this project were the development of an index of older people's health

Results

DD (Grades IV, V) was observed in 140 discs (52%) at L1/2, 159 discs (59%) at L2/3, 159 discs (59%) at L3/4, 181 discs (67%) at L4/5, and 156 discs (58%) at L5/S1. The proportions of DD were 57.3% (274 discs) in males and 60.0% (521 discs) in females but these were not significant.

Discussion

We have clarified the factors associated with MRI evaluated DD. Aging, obesity, high LDLc, occupational lifting, and sports activities are associated with DD at one or more disc levels. Atherosclerosis had previously been associated with DD [2], [22], [23]. Cardiovascular risk factors that accelerate atherosclerosis have also been suspected of being associated with DD [3], [10], [11], [12], [13], [14], [15]. We had the opportunity to examine baPWV by a simple and noninvasive method, and so we

Conclusions

In our observational study, aging, high BMI, high LDLc, occupational lifting, and sports activities were independently associated with DD at one or more disc levels. The results of this study raise our index of suspicion that cardiovascular risk factors and particular physical loading may promote DD, but additional studies are required to investigate this further. We hope that our findings will be useful in establishing preventive measures against DD and lumbar degenerative diseases.

Acknowledgments

This research is supported by the Special Coordination Funds for Promoting Science and Technology of the Ministry of Education, Culture, Sports, Science and Technology in Japan. The authors thank Dr. M. Matsuda and his colleagues for providing baPWV data, and Dr. T. Fukunaga and his colleagues for providing OSI data.

References (39)

  • Y. Kawaguchi et al.

    The association of lumbar disc disease with vitamin-D receptor gene polymorphism

    J Bone Joint Surg Am

    (2002)
  • S. Seki et al.

    A functional SNP in CILP, encoding cartilage intermediate layer protein, is associated with susceptibility to lumbar disc disease

    Nat Genet

    (2005)
  • S. Solovieva et al.

    COL9A3 gene polymorphism and obesity in intervertebral disc degeneration of the lumbar spine: evidence of gene-environment interaction

    Spine

    (2002)
  • M. Liuke et al.

    Disc degeneration of the lumbar spine in relation to overweight

    Int J Obes (Lond)

    (2005)
  • N. Yoshimura et al.

    Epidemiology of chronic disc degeneration and osteoarthritis of the lumbar spine in Britain and Japan: a comparative study

    J Rheumatol

    (2000)
  • I. Ziv et al.

    Physicochemical properties of the aging and diabetic sand rat intervertebral disc

    J Orthop Res

    (1992)
  • M.C. Battie et al.

    1991 Volvo Award in clinical sciences. Smoking and lumbar intervertebral disc degeneration: an MRI study of identical twins

    Spine

    (1991)
  • A. Ong et al.

    A pilot study of the prevalence of lumbar disc degeneration in elite athletes with lower back pain at the Sydney 2000 Olympic Games

    Br J Sports Med

    (2003)
  • L. Sward et al.

    Disc degeneration and associated abnormalities of the spine in elite gymnasts. A magnetic resonance imaging study

    Spine

    (1991)
  • Cited by (210)

    View all citing articles on Scopus

    FDA device/drug status: not applicable.

    Nothing of value received from a commercial entity related to this manuscript.

    1

    Tel.: (81) 29-853-3219; fax: (81) 29-853-3162.

    View full text