Deciphering the Threshold and Segmented Nonlinear Association Between Systemic Inflammation Response Index and Spinal...

Area of Science:

• Immunology
• Gerontology
• Endocrinology

Background:

• The Systemic Immune-Inflammation Index (SIRI), derived from neutrophil, monocyte, and lymphocyte counts, is increasingly recognized for its role in systemic inflammation.
• Bone mineral density (BMD) is a critical indicator of skeletal health, with declines associated with increased fracture risk.

Purpose of the Study:

• To investigate the association between SIRI and spinal BMD in a large adult population.
• To evaluate how age, hypertension, and diabetes influence the relationship between SIRI and spinal BMD.

Main Methods:

• A cross-sectional study analyzed data from 13,950 participants aged 20 years and older.
• SIRI was calculated from complete blood count data, and spinal BMD was measured using dual-energy X-ray absorptiometry (DXA).
• Linear regression, generalized additive models, and segmented regression analyses were employed, including subgroup analyses.

Main Results:

• A threshold effect for SIRI on spinal BMD was identified at 0.68.
• Below this threshold, SIRI was negatively correlated with spinal BMD (β = -0.0412, P = 0.0494).
• Above the threshold, SIRI showed a positive correlation with spinal BMD (β = 0.0079, P < 0.0001), with stronger associations observed in older adults and individuals with hypertension or diabetes.

Conclusions:

• A segmented, nonlinear relationship exists between SIRI and spinal BMD.
• Age, hypertension, and diabetes significantly modify this association.
• SIRI may serve as a potential biomarker for assessing osteoporosis risk.