LUMBAR SPINE DEGENERATION AND ATHEROSCLEROTIC RISK FACTORS (A 52–YEAR PROSPECTIVE STUDY OF 1337 PATIENTS)

Nicholas U. Ahn, MD,
Uri M. Ahn, MD,
Paul Sponseller, MD,
L. Nallamshetty, BS,
Porama K. Thanaporn, BS,
Peter Rose, BS,
Mesfin Lemma, MD,
J. Buchowski, MS,
John P. Kostuik, MD
Johns Hopkins Hospital Department of Orthopaedic Surgery,
Baltimore, Maryland, USA

INTRODUCTION:
A great deal of attention has been directed towards the hypothesis that lumbar spine deterioration is caused by vascular insult to the intervertebral disks or joints of the lumbar spine. More specifically, numerous authors have suggested that atherosclerotic occlusion of the lumbar vessels is a primary cause of low back pain and lumbar spine pathology, such as spondylosis and degenerative spondylolisthesis. However, no prospective studies exist which link atherosclerotic risk factors such as smoking to lumbar spine pathology. Such knowledge would give further insight into the etiology of lumbar spine degeneration and hopefully lead investigators in the correct direction when searching for a solution to this costly and ubiquitous problem.

MATERIALS AND METHODS:
Graduates from the medical school classes from 1948–1964 at our institution were asked to participate in a longitudinal study which was started in 1949; 1337 physicians consented to this study. All volunteers had medical records and questionnaires sent in each year; all data were stored and recorded. Risk factors for athersoclerosis were identified: smoking history, diabetes mellitus, hypertension, hypercholesterolemia, hyperlipidemia, CAD, peripheral vascular disease, and obesity. The subsequent development of lumbar spine pathology including low back pain, lumbar spondylosis, degenerative spondylolisthesis, HNP, and spinal stenosis was determined. A stepwise logistic regression was utilized to determine whether or not development of each lumbar spine process was associated with different atherosclerotic risk factors. The contributions of age and sex were corrected for.

RESULTS:
Development of back pain was significantly associated with prior positive smoking history (p=0.02), hypertension (p=0.03), and CAD (p=0.04). Also, a positive association existed between pack years smoked and back pain (p=0.04), and a negative association existed between number of years quit and back pain (p=0.05). Development of degenerative spondylosis and spondylolisthesis were significantly associated with prior positive smoking history (p <0.05), hypertension (p=0.03), coronary artery disease (p=0.01), and hypercholesterolemia (p=0.03). CONCLUSION: Smoking, hypertension, and CAD are all associated with development of low back pain. These same factors, as well as hypercholesterolemia, are associated with development of degenerative lumbar spondylosis and spondylolisthesis. This suggests that the vascular hypothesis to the etiology of low back pain is valid.