Background Pelvic incidence (PI) is a fundamental morphologic parameter of spinopelvic alignment and is traditionally considered largely constant in adulthood. However, the extent to which PI is influenced by age, sex, or degenerative spinal pathology remains uncertain. Objective To evaluate the relationship of PI with age, sex, and degenerative disc disease (DDD) in an adult population and to identify independent predictors of lumbar lordosis (LL) and DDD. Methods This retrospective cross-sectional study included adults aged 40–60 years who underwent standardized lateral lumbopelvic radiography between 2019 and 2024. Individuals with prior spinal surgery, congenital anomalies, infection, tumor, or inadequate imaging were excluded. Spinopelvic parameters (PI, pelvic tilt [PT], sacral slope [SS], LL) were measured by two independent observers, and interobserver reliability was assessed using intraclass correlation coefficients. Group comparisons were performed using the Mann–Whitney U test, correlations with Spearman analysis, and multivariable regression models were constructed to determine independent predictors of LL and DDD. Results A total of 319 participants (mean age 49.7 ± 6.1 years) were analyzed. No sex-related differences were observed in PI, PT, SS, or LL (p > 0.05). Individuals with DDD had higher SS and LL (both p < 0.001), whereas PI did not differ between the groups (p = 0.166). Age showed a moderate negative correlation with PI (ρ = –0.346, p < 0.001). In multivariable analysis, SS (β = 1.83), PI (β = –0.88), PT (β = 0.44), and female sex (β = 5.01) independently predicted LL. Age was the sole independent predictor of DDD (OR = 1.29 per year). Conclusion In adults aged 40–60 years, pelvic incidence was not significantly associated with sex or radiographically detectable degenerative disc disease and appeared largely stable, although lower PI values were associated with older age in this cross-sectional cohort. Degenerative changes predominantly affect positional parameters (SS and LL) rather than the morphologic parameter PI. These findings reinforce the role of pelvic incidence as a key structural reference in the assessment of sagittal balance. Level of Evidence Level III (retrospective cross-sectional study).

Association of Pelvic Incidence with Age, Sex, and Degenerative Spinal Pathology: A Retrospective Radiological Study

期刊论文
发表日期：

2026年7月2日

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Mustafa Bulut,
Muhammed Furkan Darılmaz

摘要

Background

Pelvic incidence (PI) is a fundamental morphologic parameter of spinopelvic alignment and is traditionally considered largely constant in adulthood. However, the extent to which PI is influenced by age, sex, or degenerative spinal pathology remains uncertain.

Objective

To evaluate the relationship of PI with age, sex, and degenerative disc disease (DDD) in an adult population and to identify independent predictors of lumbar lordosis (LL) and DDD.

Methods

This retrospective cross-sectional study included adults aged 40–60 years who underwent standardized lateral lumbopelvic radiography between 2019 and 2024. Individuals with prior spinal surgery, congenital anomalies, infection, tumor, or inadequate imaging were excluded. Spinopelvic parameters (PI, pelvic tilt [PT], sacral slope [SS], LL) were measured by two independent observers, and interobserver reliability was assessed using intraclass correlation coefficients. Group comparisons were performed using the Mann–Whitney U test, correlations with Spearman analysis, and multivariable regression models were constructed to determine independent predictors of LL and DDD.

Results

A total of 319 participants (mean age 49.7 ± 6.1 years) were analyzed. No sex-related differences were observed in PI, PT, SS, or LL (p > 0.05). Individuals with DDD had higher SS and LL (both p < 0.001), whereas PI did not differ between the groups (p = 0.166). Age showed a moderate negative correlation with PI (ρ = –0.346, p < 0.001). In multivariable analysis, SS (β = 1.83), PI (β = –0.88), PT (β = 0.44), and female sex (β = 5.01) independently predicted LL. Age was the sole independent predictor of DDD (OR = 1.29 per year).

Conclusion

In adults aged 40–60 years, pelvic incidence was not significantly associated with sex or radiographically detectable degenerative disc disease and appeared largely stable, although lower PI values were associated with older age in this cross-sectional cohort. Degenerative changes predominantly affect positional parameters (SS and LL) rather than the morphologic parameter PI. These findings reinforce the role of pelvic incidence as a key structural reference in the assessment of sagittal balance.

Level of Evidence

Level III (retrospective cross-sectional study).