Vertebral deformities

Vertebral deformities

LASA filenames:
LASAzo22
LASAzo23.sps (syntax to create variables for analyses)

Contact: Natasja van Schoor

Background
Osteoporosis is a common skeletal disorder that causes pain, physical limitations and disability in later life.(1) Vertebral deformity is a common consequence of osteoporosis and occurs frequently in older people. The prevalence of vertebral deformities varies between 6% and 40% among people aged 50 years and older depending on the definition used.(2,3) The incidence of clinically diagnosed vertebral fractures increases with age from about zero at age 50 years to 30 per 1000 at age 80.(4) Vertebral deformities, even if they are not clinically manifest, may have a substantial impact on the level of functioning and well-being in older people.(5-11) Moreover, the presence of a vertebral deformity is a strong predictor for subsequent hip fractures.(12,13)

Measurement instruments in LASA
LASA respondents who participated in the C-examination (1995/1996), were born in 1930 and before (aged 65 years and older as of 1 January, 1996) and were living in the west of the Netherlands (Amsterdam and its surroundings) were invited to the VU University Medical Center for a spinal lateral radiograph. Of the 695 respondents who were invited, 535 respondents (77%) were willing to come to the hospital. Non-responders were older, had more functional limitations and lower self-perceived health, but had a similar gender distribution.(12) Valid spinal radiographs were obtained in 527 of these participants. Only respondents with a valid lateral radiograph at LASA-C were invited for a repeated lateral radiograph at LASA-D examination (1998/1999). In total, 338 subjects had a valid repeated spinal radiograph at LASA-D.

Ascertainment of vertebral deformities
Lateral radiographs of the thoracic and lumbar spine (T4-L5) were obtained in each participant with X-ray scans according to the protocol of the European Vertebral Osteoporosis Study.(4) The thoracic film was centered at T7 and the lumbar film at L2. The X-ray tube-to-film distance was 115 cm. Assessment of vertebral deformities can be performed by using both semiquantitative (14) and quantitative criteria.(15-17) In LASA, semiquantitative assessment has been performed.

In the semiquantitative approach,(14) vertebrae T4-L4 were first graded on visual inspection without direct vertebral measurement by a researcher and a trained clinician with specific expertise in the radiology of osteoporosis. First the type of the deformity was assessed. Osteoporosis-induced vertebral fractures are usually classified into three types: crush, wedge, and biconcave. A crush fracture involves compression of the entire vertebral body. In wedge fractures, there is anterior collapse. In biconcave vertebral fractures, the anterior and posterior height are maintained, but there is central compression of the end plate regions, resulting in a biconcave appearance. Second, the severity of the deformity was graded as:

1 (less than 20% reduction in anterior, middle, and/or posterior height),
2 (approximately 20-25% reduction in anterior, middle, and/or posterior height),
3 (approximately 25-30% reduction in anterior, middle, and/or posterior height),
4 (approximately 30-40% reduction in anterior, middle, and/or posterior height),
5 (approximately 40-50% reduction in anterior, middle, and/or posterior height), or
6 (>50% reduction in anterior, middle, and/or posterior height).

For the analyses, this grading categories were recoded according to commonly used categories.(11,14). Vertebrae T4-L5 were reclassified as: grade 0, no deformity (less than 20% reduction in vertebral height), grade 1, mild deformity (20-25% reduction in vertebral height), grade 2, moderate deformity (approximately 25-30% reduction in height) and grade 3, severe deformity (approximately 30% or greater reduction in height). The cut-off points of the two highest categories vary across studies and were also defined as 25-40% (grade 2) and >40% (grade 3). A vertebra scoring of grade 1 or higher is considered a deformed vertebra. Respondents with mild vertebral deformities were defined as having at least one grade 1 deformity without grade 2 or grade 3 deformities. Respondents with moderate vertebral deformities were defined as having at least one grade 2 deformity without grade 3 deformities, while severe deformities were defined as having at least one grade 3 deformity. In a random sample of 50 radiographs, the intra-observer agreement of this classification was tested with weighted 6-scores.(18) The kappa-score was weighted as described by Altman.(19) Weighted kappa-scores for presence of deformity (y/n), severity and number of deformities were 0.80, 0.75 and 0.63, respectively.

Availability of information per wave ¹

BCDE
2B*		FGH

3B*		MB*IJK
Vertebral deformities

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¹ More information about the LASA data collection waves is available here.

* 2B=baseline second cohort;
3B=baseline third cohort;
MB=migrants: baseline first cohort

Previous use in LASA
Pluijm et al. (2000) studied the prevalence of the number and severity of vertebral deformities in men and women using the lateral radiographs of LASA-C, and determined the extent to which these are associated with several aspects of functioning. The results of this study showed that the prevalence of having at least one vertebral deformity was 39% in both men and women. Six percent of the men and 5% of the women had at least three vertebral deformities. For severe deformities, the prevalence was 8% in men and 12% in women. In addition, it was shown that vertebral deformities have a substantial impact on the level of functioning and well-being of older people. In two papers in which genetic factors for osteoporosis (Pluijm et al., 2004; Pluijm et al., 2002) were examined, the presence of prevalent vertebral deformity was used as outcome measure. We demonstrated that apolipoprotein E e4 (ApoE e4), but not collagen type I a1 (COLIA1) Sp1 polymorphism, was associated with an increased risk of moderate and severe vertebral deformities. Van Schoor et al. (2005) compared the quality of life after vertebral fractures with the quality of life after other chronic diseases.


References

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  2. Melton III LJ, Lane AW, Cooper C, Eastell R, O’Fallon WM, Riggs BL. Prevalence and incidence of vertebral deformities. Osteoporos Int 1993; 3: 113-119.
  3. O’Neill TW, Felsenberg D, Varlow J, Cooper C, Kanis JA, Silman AJ. The prevalence of vertebral deformity in European men and women: the European Vertebral Osteoporosis Study. J Bone Miner Res 1996; 11:1010-1018.
  4. Cooper C, Atkinson EJ, O’Fallon WM, Melton III LJ. Incidence of clinically diagnosed vertebral fractures: a population-based study in Rochester, Minnesota, 1985-1989. J Bone Miner Res 1992; 7:221-227.
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  14. Genant HK, Wu CY, van Kuijk C, Nevitt MC. Vertebral fracture assessment using a semiquantitative technique. J Bone Miner Res 1993; 8: 1137-1148.
  15. Melton LJ, Kan SH, Frye MA, Wahner HW, O’Fallon WM, Riggs BL. Epidemiology of vertebral fractures in women. Am J Epidemiol 1989; 129: 1000-1001.
  16. Eastell R, Cedel SC, Wahner HW, Riggs BL, Melton LJ III. Classification of vertebral fractures. J Bone Miner Res 1991; 6: 207-215.
  17. McCloskey EV, Spector TD, Eyres KS et al. The assessment of vertebral deformity: a method for use in population studies and clinical trials. Osteoporos Int 1993; 3: 138-147.
  18. Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics 1977; 33: 159-174.
  19. Altman DG. Practical statistics for medical research. Chapman & Hall, London, 1991.
  20. Kellgren JH, Jeffrey MR, Ball J. The Epidemiology of Chronic Rheumatism: Atlas of Standard Radiographs. 2nd Edition. Blackwell Scientific, Oxford, 1963.


Date of last update: April 4, 2020