Abstract
Purpose
To investigate associations between sagittal thoracolumbar spine shape with sex and measures of adiposity throughout adulthood.
Methods
Thoracolumbar spine shape was characterised using statistical shape modelling on lateral dual-energy x-ray absorptiometry images, recorded for vertebral fracture analysis, of the spine from 1529 participants of the MRC National Survey of Health and Development, acquired at age 60–64 years. Associations between spine shape modes (SM) and 1) sex, 2) contemporaneous measures of overall and central adiposity (indicated by body mass index and waist circumference, respectively), 3) changes in total and central adiposity during earlier stages of adulthood and age at onset of overweight, were investigated.
Results
Four of the first eight spine modes (SM) describing lumbar spine shape differed by sex; on average, women had more lordotic spines than men with relatively smaller but caudally increasing anterior-posterior (a-p) vertebral diameters. Greater BMI and waist circumference and earlier onset of overweight were associated with uneven (or snaking) spinal curvatures (SM2) and larger a-p vertebral diameters (SM3). Central adiposity was also associated with larger caudal disc heights (SM4) in women, especially increases between 36–43 years.
Conclusions
Sagittal spine shapes differed by sex and associations with overall and central adiposity also differed. Overweight and greater central adiposity earlier in adulthood were particularly important, and were associated with a straighter but more unevenly curved spine with larger vertebrae and caudal discs heights, possibly explained by a chronic effect of increased mechanical loading on the spine.
Conflicts of interest: None
Funding received from MRC
