Deterioration of sagittal spinal alignment with age originates from the pelvis not the lumbar spine: a 4-year longitudinal cohort study.

Purpose: There is controversy regarding age-related deterioration of spinal sagittal alignment in cross-sectional study. Although we reported that deterioration in spinal alignment originated at the cervical spine in males and the pelvis in females, others studies have indicated that the lumbar spine is initially implicated in both sexes. The purpose of this study was to clarify these differences in a longitudinal cohort study.

Methods: Our analysis was based on 237 individuals aged 60-89 years who participated in our health screening study in 2014 and 2018. They were classified into six groups by birth year and sex: 60-69 years (26 males, 49 females); 70-79 years (35 males, 88 females); and 80-89 years (19 males, 20 females). The following parameters were measured from standing radiographs: pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis, T1 slope, cervical lordosis, C7 sagittal vertical axis (C7 SVA), and C2-7 SVA.

Results: In males, the first significant change was an increase in the PT angle (19°, in 2014, to 21°, in 2018) in the 80-89 years age group (P < 0.05), with no significant deterioration in cervical parameters. In females, spinal deterioration included a change in the SS (32°-30°), PT (18°-20°), and SVA (- 8 to 6 mm) in the 60-69 years age group (P < 0.05), with no change in the LL.

Conclusions: Contrary to prior studies, our longitudinal data indicated that deterioration in spinal alignment originates in the pelvis for both sex but develops earlier in females than males.