The Relationship Between high-sensitivity C-Reactive Protein Levels and Asthma in Middle-Aged and Elderly Chinese Population: A Cross-Sectional Study Based on China Health and Retirement Longitudinal Study (CHARLS)

Systemic inflammation has been increasingly recognized as a potential contributor to asthma pathogenesis, particularly in middle-aged and older populations.
This study aimed to examine the association between serum High-sensitivity C-reactive protein (hs-CRP) levels and asthma in middle-aged and older adults in China.
Data were drawn from the China Health and Retirement Longitudinal Study (CHARLS, 2011–2015). After performing 6:1 propensity score matching (PSM), a total of 3,677 participants aged ≥45 years were included in the analysis. Multivariate binary logistic regression was used to assess the association between hs-CRP levels, relevant covariates, and asthma prevalence.
Following PSM, asthma patients exhibited significantly higher hs-CRP levels compared to matched non-asthmatic controls. Moderate hs-CRP levels (1–3 mg/L) were associated with increased odds of asthma (OR = 1.54, 95% CI [1.23, 1.93], p < 0.001). High hs-CRP levels (≥3 mg/L) showed a similar association (OR = 1.62, 95% CI [1.24–2.11], p < 0.001). Asthma was also significantly linked to the presence of cardiovascular disease (CVD) (p < 0.001). Additionally, asthma patients had a higher proportion of abnormal white blood cell (WBC) counts compared to non-asthmatic individuals (p = 0.018).
Elevated hs-CRP levels are significantly associated with asthma in Chinese adults over 45 years of age. Asthma also shows a notable comorbidity with CVD in this population. Early identification and management of systemic inflammation may help reduce the overall burden of asthma and related conditions in older adults.