L-Shaped Association of C-Reactive Protein-Albumin-Lymphocyte Index and COPD Incidence: A Nationwide Cohort Study in the UK Biobank
- 1Department of Laboratory Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, People’s Republic of China
- 2Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, People’s Republic of China
Abstract
Background: The C-reactive protein–albumin–lymphocyte (CALLY) index has shown prognostic value in various chronic conditions, but its prospective association with incident chronic obstructive pulmonary disease (COPD) and potential non-linear dose–response patterns remain unexplored.
Methods: This prospective cohort study included 292,945 UK Biobank participants. Multivariable Cox proportional hazards regression was used to estimate the association between the natural-log-transformed CALLY (ln-CALLY) index and incident COPD. Restricted cubic spline (RCS) curves and two-segment Cox regression were applied to characterize non-linear associations and identify inflection points. Subgroup and sensitivity analyses were conducted to assess robustness.
Results: During a mean follow-up of 13.6 years, 6618 incident COPD events occurred. Each one-unit increment in ln-CALLY was associated with a 17% lower risk of COPD in the fully adjusted model (HR = 0.83, 95% CI: 0.81–0.85, P < 0.001). The highest quartile exhibiting a 41% risk reduction versus the lowest (HR = 0.59, 95% CI: 0.54–0.64, P < 0.001). RCS analysis revealed a significant L-shaped relationship. Threshold effect analysis identified an inflection point at ln-CALLY = 7.00; below this threshold, each one-unit increase was associated with a 19% risk reduction (HR = 0.81, 95% CI: 0.78–0.83, P < 0.001), whereas above the threshold the association was non-significant. The inverse association was more pronounced in participants aged <65 years. Sensitivity analyses yielded consistent results.
Conclusion: The CALLY index exhibits a significant L-shaped association with incident COPD risk, characterized by a pronounced protective effect below ln-CALLY = 7.00 and a risk plateau above this threshold. These findings support the broader concept that immuno-nutritional status is a determinant of respiratory health.
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BibTeX
@article{shi2026lshaped,
title = {{L-Shaped Association of C-Reactive Protein-Albumin-Lymphocyte Index and COPD Incidence: A Nationwide Cohort Study in the UK Biobank}},
author = {Yushan Shi and Huihui Jiang and Shuangshuang Pu and Yaobei Liu and Yan Wang and Weifang Liu},
journal = {International Journal of Chronic Obstructive Pulmonary Disease},
year = {2026},
month = oct,
doi = {10.2147/copd.s640670},
url = {https://doi.org/10.2147/copd.s640670},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - L-Shaped Association of C-Reactive Protein-Albumin-Lymphocyte Index and COPD Incidence: A Nationwide Cohort Study in the UK Biobank
AU - Yushan Shi
AU - Huihui Jiang
AU - Shuangshuang Pu
AU - Yaobei Liu
AU - Yan Wang
AU - Weifang Liu
PY - 2026
DA - 2026/10/30
JO - International Journal of Chronic Obstructive Pulmonary Disease
DO - 10.2147/copd.s640670
UR - https://doi.org/10.2147/copd.s640670
AB - Background: The C-reactive protein–albumin–lymphocyte (CALLY) index has shown prognostic value in various chronic conditions, but its prospective association with incident chronic obstructive pulmonary disease (COPD) and potential non-linear dose–response patterns remain unexplored. Methods: This prospective cohort study included 292,945 UK Biobank participants. Multivariable Cox proportional hazards regression was used to estimate the association between the natural-log-transformed CALLY (ln-CALLY) index and incident COPD. Restricted cubic spline (RCS) curves and two-segment Cox regression were applied to characterize non-linear associations and identify inflection points. Subgroup and sensitivity analyses were conducted to assess robustness. Results: During a mean follow-up of 13.6 years, 6618 incident COPD events occurred. Each one-unit increment in ln-CALLY was associated with a 17% lower risk of COPD in the fully adjusted model (HR = 0.83, 95% CI: 0.81–0.85, P < 0.001). The highest quartile exhibiting a 41% risk reduction versus the lowest (HR = 0.59, 95% CI: 0.54–0.64, P < 0.001). RCS analysis revealed a significant L-shaped relationship. Threshold effect analysis identified an inflection point at ln-CALLY = 7.00; below this threshold, each one-unit increase was associated with a 19% risk reduction (HR = 0.81, 95% CI: 0.78–0.83, P < 0.001), whereas above the threshold the association was non-significant. The inverse association was more pronounced in participants aged <65 years. Sensitivity analyses yielded consistent results. Conclusion: The CALLY index exhibits a significant L-shaped association with incident COPD risk, characterized by a pronounced protective effect below ln-CALLY = 7.00 and a risk plateau above this threshold. These findings support the broader concept that immuno-nutritional status is a determinant of respiratory health.
SN - 1176-9106
SN - 1178-2005
ER -