Degenerative inter-vertebral disc disease osteochondrosis intervertebralis in Europe: prevalence, geographic variation and radiological correlates in men and women aged 50 and over

Abstract

Objectives: To assess the prevalences across Europe of radiological indices of degenerative inter-vertebral disc disease (DDD); and to quantify their associations with, age, sex, physical anthropometry, areal BMD (aBMD) and change in aBMD with time.

Methods: In the population-based European Prospective Osteoporosis Study, 27 age-stratified samples of men and women from across the continent aged 50+ years had standardized lateral radiographs of the lumbar and thoracic spine to evaluate the severity of DDD, using the Kellgren-Lawrence (KL) scale. Measurements of anterior, mid-body and posterior vertebral heights on all assessed vertebrae from T4 to L4 were used to generate indices of end-plate curvature.

Results: Images from 10 132 participants (56% female, mean age 63.9 years) passed quality checks. Overall, 47% of men and women had DDD grade 3 or more in the lumbar spine and 36% in both thoracic and lumbar spine. Risk ratios for DDD grades 3 and 4, adjusted for age and anthropometric determinants, varied across a three-fold range between centres, yet prevalences were highly correlated in men and women. DDD was associated with flattened, non-ovoid inter-vertebral disc spaces. KL grade 4 and loss of inter-vertebral disc space were associated with higher spine aBMD.

Conclusion: KL grades 3 and 4 are often used clinically to categorize radiological DDD. Highly variable European prevalences of radiologically defined DDD grades 3+ along with the large effects of age may have growing and geographically unequal health and economic impacts as the population ages. These data encourage further studies of potential genetic and environmental causes.

Keywords: Kellgren–Lawrence grading; age range 50 plus years; bone mineral density (BMD); degenerative disease; intervertebral disc; multi-centre prevalence study; osteochondrosis intervertebralis; plane radiology; population-based; reproducibility study.

Fig 1

Diagram to show how the Index of End-Plate Concavity (IEPC) is calculated for a single vertebra. Individual vertebral height measurements were made as described in O’Neill et al and as shown diagrammatically by the arrows (14). Thoracic and Lumbar IEPC values were, for the purposes of this paper, calculated by averaging the individual IEPC values for the 9 thoracic and 4 lumbar vertebrae respectively.

Fig 2

Combinations of radiological diagnoses and distributions of K-L scores across 4 grades in the Lumbar and Thoracic spine. Combinations of KL scores add up to 100% (ordinate scale). Note that no subject scored zero on the K-L score. Represented are: subjects with a vertebral fracture; subjects with Scheuermann’s disease; subjects with Forestier’s disease; and subjects with none of these diagnoses and all combinations.

Fig 3

Prevalences in the Lumbar and Thoracic spine of DDD KL grades 3+4 associated with (left) age, (centre) nationality and European Region and (right) Investigational Centre, all adjusted to age 65 and shown with 95% confidence intervals. Men and women are shown separately. Key to country codes, right hand graph: BE Belgium; DE Germany; ES Spain; FR France; GR Greece; HU Hungary; IT Italy; NL Netherlands; PL Poland; PO Portugal; RU Russia; SE Sweden; SK Slovakia; UK United Kingdom.

Fig 4

left: distribution of numbers (y axis) of degenerative vertebral deformities per vertebral column (13 vertebrae evaluated) in this population. It can be seen that 85% of subjects were unaffected by degenerative vertebral deformities. right: distribution of numbers of inter-vertebral discs of reduced height per vertebral column. The percentages show the proportions of the population in each category.