Adult spinal deformity and its relationship with height loss: a 34-year longitudinal cohort study.

Background: Age-related height loss is a normal physical change that occurs in all individuals over 50 years of age. Although many epidemiological studies on height loss have been conducted worldwide, none have been long-term longitudinal epidemiological studies spanning over 30 years. This study was designed to investigate changes in adult spinal deformity and examine the relationship between adult spinal deformity and height loss.

Methods: Fifty-three local healthy subjects (32 men, 21 women) from Furano, Hokkaido, Japan, volunteered for this longitudinal cohort study. Their heights were measured in 1983 and again in 2017. Spino-pelvic parameters were compared between measurements obtained in 1983 and 2017. Individuals with height loss were then divided into two groups, those with degenerative spondylosis and those with degenerative lumbar scoliosis, and different characteristics were compared between the two groups.

Results: The mean age of the subjects was 44.4 (31-55) years at baseline and 78.6 (65-89) years at the final follow-up. The mean height was 157.4 cm at baseline and 153.6 cm at the final follow-up, with a mean height loss of 3.8 cm over 34.2 years. All parameters except for thoracic kyphosis were significantly different between measurements taken in 1983 and 2017 (p < 0.05). Height loss in both sexes was related to changes in pelvic parameters including pelvic incidence-lumbar lordosis (R = 0.460 p = 0.008 in men, R = 0.553 p = 0.012 in women), pelvic tilt (R = 0.374 p = 0.035 in men, R = 0.540 p = 0.014 in women), and sagittal vertical axis (R = 0.535 p = 0.002 in men, R = 0.527 p = 0.017 in women). Greater height loss was more commonly seen in women (p = 0.001) and in patients with degenerative lumbar scoliosis (p = 0.02).

Conclusions: This longitudinal study revealed that height loss is more commonly observed in women and is associated with adult spinal deformity and degenerative lumbar scoliosis. Height loss is a normal physical change with aging, but excessive height loss is due to spinal kyphosis and scoliosis leading to spinal malalignment. Our findings suggest that height loss might be an early physical symptom for spinal malalignment.