Interaction of hypertension and remnant cholesterol on arterial stiffness in Chinese middle-aged and elderly populations

Objective Arterial stiffness (AS) is a critical pathological basis for major cardiovascular diseases (CVD), with its progression closely associated with modifiable risk factors such as hypertension and dyslipidemia. Remnant cholesterol (RC), a key dyslipidemia indicator, is increasingly recognized for its cardiovascular risk predictive value independent of low-density lipoprotein cholesterol (LDL-C). This study explored the independent and additive interactive associations of hypertension and RC with AS in a Chinese middle-aged and elderly population, so as to provide evidence-based support for the prevention and management of cardiovascular diseases in this high-risk population. Methods A retrospective cohort study was conducted on 6,886 middle-aged and elderly participants (≥ 45 years) who underwent health examinations at the Health Management Center of Zigong Fourth People’s Hospital from January to December 2023. All participants completed measurements of brachial-ankle pulse wave velocity (baPWV) for AS assessment, blood pressure, blood lipids, and other biochemical indicators. Participants were stratified into the AS group (baPWV ≥ 1800 cm/s) and normal group (baPWV < 1800 cm/s). Multiple analytical approaches were used to analyze the relationship between hypertension, RC and AS: multivariable logistic regression models (adjusted for age, gender, BMI, smoking history, drinking history, diabetes, and other confounding factors) were applied to evaluate their independent and joint effcets with AS; participants were further divided into four subgroups (low RC without hypertension, high RC without hypertension, low RC with hypertension, high RC with hypertension) to assess the interaction of the two factors on AS risk; additive interaction models were constructed to quantify their additive interaction; restricted cubic spline (RCS) models were used to explore the non-linear relationship between blood pressure and AS risk and to identify apparent inflection points within the study population. Results Of the 6,886 participants, 4,702 (68.3%) were identified with AS. Both hypertension and elevated RC were independently associated with an increased odds of AS ( P < 0.001). Participants with both hypertension and high RC exhibited the highest risk of AS (OR = 3.50, 95% CI: 2.66–4.61) compared to the low RC without hypertension. A additive interaction between hypertension and elevated RC on AS was observed, with the relative excess risk due to interaction (RERI) = 1.21 (95% CI: 0.13–2.23). The RCS model identified apparent inflection points around 127 mmHg for systolic blood pressure (SBP) and 84 mmHg for diastolic blood pressure (DBP), where the risk of AS appeared to increase more rapidly within the study population. Conclusion This study identified an additive interaction between hypertension and elevated RC in relation to AS among middle-aged and elderly Chinese adults. These findings suggest that the integrated assessment of hypertension and RC may provide complementary information for identifying individuals at increased risk of AS.