Cumulative exposure to remnant cholesterol and new-onset hypertension in middle-aged and older adults: a nationwide prospective cohort study with mediation analysis.

The association between remnant cholesterol (RC) and the risk of developing hypertension remains poorly elucidated. We analyzed China Health and Retirement Longitudinal Study data (CHARLS, 2011-2020). RC was categorized into baseline RC, cumulative RC, and RC change. In Cohort 1 (n = 7474), baseline RC was measured at Wave 1, with incident hypertension identified during Waves 2-5. In Cohort 2 (n = 3956), cumulative RC was calculated using Waves 1 and 3 data, with hypertension assessed during Waves 4-5. Participants were divided into quartiles. Logistic regression was used to assess the association between RC and hypertension. Restricted cubic splines explored non-linear relationships. During follow-up, 2366 (31.7%) and 805 (20.3%) hypertension cases occurred in Cohorts 1 and 2, respectively. A non-linear association was found between baseline RC and hypertension, with an inflection point at 1.16 mmol/L. The highest RC quartile showed increased hypertension risk, with adjusted odds ratios (OR) of 1.52 (p < 0.001) for baseline RC and 1.39 (p = 0.004) for cumulative RC. RC change suggested potential increased risk, though not statistically significant. BMI and HbA1c partially mediated the RC-hypertension relationship, accounting for 36.94 and 7.2% of the total effect, respectively. These findings indicate that elevated baseline and cumulative RC levels are associated with an increased risk of new-onset hypertension in middle-aged and older adults, and that baseline RC levels and hypertension are non-linearly related, with an inflection point of 1.16 mmol/L. Additionally, this study found that BMI and HbA1c mediated the association between RC and incident hypertension.