Relationship of total sagittal spinal alignment index of thoracic kyphosis and lumbar lordosis with physical function in community-dwelling older adults.

BACKGROUND

Overall spinal curvature is evaluated by calculating the difference between the angles of lumbar lordosis (LL) and thoracic kyphosis (TK) and is expressed as LL minus TK (LL-TK). It is unclear whether LL-TK is associated with physical function in community-dwelling older adults and whether it is more relevant than TK or LL alone.

OBJECTIVE

This study aimed to identify whether LL-TK is associated with physical function in community-dwelling older adults, and whether it is strongly associated than TK or LL alone.

METHODS

The participants comprised 1,674 community-dwelling older adults who underwent physical assessments (women, n = 1,099; mean age, 67.4 ± 5.3 years). As spinal alignment indices, TK and LL were measured using skin surface methods, and LL-TK was calculated as the difference between them. Decreased LL-TK indicated increased overall spinal curvature. Physical function was determined by measuring single-leg standing, five-times chair-stand, and usual gait speed. Stepwise multiple regression analyses were performed with each physical function as the dependent variable and spinal alignment indices as the independent variables, with adjustments.

RESULTS

Multiple regression analyses showed that single-leg standing (β = 0.092, 95% confidence interval [CI] = 0.071 to 0.214, p < .001) and five-times chair-stand (β=-0.142, 95% CI = -0.037 to -0.019, p < .001) were significantly associated with LL-TK, but not LL. Both LL-TK (β = 0.121, 95% CI = 0.001 to 0.004, p < .001) and LL (β = 0.087, 95% CI = 0.001 to 0.003, p = .003) were significant determinants of usual gait speed.

CONCLUSIONS

This study showed that decreased LL-TK may be associated with poor physical function. This association may be stronger than that observed for TK or LL alone.