Sex modifies the association between blood pressure variability and lung function decline among population over 45 years old: a pooled analysis of two national cohorts.

Background: The evidence linking blood pressure (BP) variability (BPV) to longitudinal lung function decline remains unclear. This cohort study aims to reveal the association between BPV and lung function decline among population over 45 years old. Methods: Participants were from the Health and Retirement Study (HRS) and the China Health and Retirement Longitudinal Study (CHARLS). Lung function was assessed by peak expiratory flow (PEF), and was standardized using Z-score transformation. Variation independent of mean (VIM) was mainly used to assess BPV. A linear mixed model was conducted. Subgroup analyses across age, sex, body mass index (BMI), and hypertension status were employed. A meta-analysis was performed to pool results, with heterogeneity reported. Results: A total of 6,930 and 5,119 eligible participants from HRS and CHARLS were included, respectively. With increment of VIM, participants' PEF decreased. Pooled analysis revealed that increased BPV was significantly associated with faster lung function decline [β for systolic BP: -0.224, 95% confidence interval (CI): -0.323 to -0.126; β for diastolic BP: -0.08, 95% CI: -0.011 to -0.005]. Compared with participants in the lowest tertile of VIM, those in the middle and highest tertiles showed greater declines. Subgroup analysis demonstrated that sex modified this association, with a more pronounced effect observed in males (pooled β for systolic BP: -0.347, 95% CI: -0.669 to -0.025; pooled β for diastolic BP: -0.012, 95% CI: -0.019 to -0.005). Conclusions: BPV is significantly associated with lung function decline in middle-aged and older adults, and this association is more pronounced in males. More early intervention for individuals with higher BPV is needed, particularly for males.