Background Spinal mobility is one of the core outcomes recommended by the Assessment of Spondyloarthritis international Society (ASAS) in the follow-up of patients with axial spondyloarthritis (SpA). It is, however, currently unknown what are the reference values for the recommended spinal mobility measures in healthy subjects and to what extent they are influenced by age.
Objectives To assess the effect of age on spinal mobility measures among healthy people.
Methods A cross-sectional study (``MOBILITY study”) was conducted among healthy volunteers aged 20-69 years old. Recruitment was stratified by gender, age (10-year categories) and height (10cm categories). Participants were anyone Caucasian volunteering to be measured in the Netherlands and Portugal. Exclusion criteria were factors potentially influencing spinal mobility (eg. back surgery, low back pain). Several spinal mobility measures (see table) were investigated and they were compared across all age categories with analysis of variance followed by analyses to identify which groups were significantly different. The population was further divided according to the cutoff of 50 years old. The mean values were compared by independent sample t-test, Mann Whitney and chi-square, as appropriate. The Bath Ankylosing Spondylitis Mobility Score (BASMI) was calculated, according to its original definition (with cervical rotation in lying position and 15cm Schober) and also as recommended by the ASAS (with cervical rotation in sitting position and 10cm Schober).
Results A total of 393 volunteers were included, 51% males and with a mean age of 43.9 (SD 13.9) years. A significant decrease in all spinal mobility measures with increasing age was found, particularly between the older categories (50-59 and 60-69 years) and the younger categories (20-29 and 30-39). For instance, a cervical rotation of 79 (SD 9) was obtained for the 20-29 category, 78 (SD 10) for the 30-39 category, 75 (SD 10) for the 40-49 category, 71 (SD 8) for the 50-59 category and 66 (SD 10) for the 60-69 category, with a significant difference between each of the first three and the last two categories. Thereafter, the population was divided according to the cutoff of 50 years old, as axial SpA is rarely diagnosed after the age of 50, and a reference value for spinal mobility is therefore most relevant in this age category. There were significant differences in all the measures between the two age groups (table).
Conclusions All spinal mobility measures significantly decrease with increasing age, which should be taken into account when assessing older patients.
Disclosure of Interest None Declared