Interaction Analysis of Abnormal Lipid Indices and Hypertension for Ischemic Stroke: A 10-Year Prospective Cohort Study

BACKGROUND: Dyslipidemia and hypertension are two important independent risk factors for ischemic stroke (IS); however, their combined effect on IS remains uncertain. OBJECTIVES: This present study aimed to evaluate the interaction effect of hypertension and abnormal lipid indices on IS in a 10-year prospective cohort in Chinese adults. METHODS: The cohort study of 4,128 participants was conducted in May 2009 and was followed up to July 2020. All qualified participants received a questionnaire survey, physical examination, and blood sample detection. Cox regression was used to evaluate the association of dyslipidemia and hypertension with IS, and calculate the hazard ratio (HR) and 95% confidence interval (CI). The relative excess risk of interaction (RERI) and the HR (95%CI) of interaction terms were used to examine additive and multiplicative interactions. RESULTS: In the hypertensive population, Non-HDL-C ≥190 mg/dl, LDL-C/HDL-C ≥2 and HDL-C ≥60 mg/dl were statistically associated with IS, and after adjusting for covariates, HRs (95%CIs) were 1.565 (1.007–2.429), 1.414 (1.034–1.933) and 0.665 (0.450–0.983), respectively. While in the non-hypertension population, no significant association of Non-HDL-C ≥190 mg/dl, LDL-C/HDL-C ≥2, and HDL-C ≥60 was detected with IS (P > 0.05). There was a significant association between TC/HDL-C ≥ 3.6 and the decreased risk of IS in the non-hypertension population, and the HR (95%CI) was 0.479 (0.307–0.750). Whereas, a similar association was not observed in the hypertensive population. HDL-C ≥ 60 mg/dl, Non-HDL-C ≥ 190 mg/dl, TC/HDL-C ≥ 3.6, and TG/HDL-C ≥ 1 have additive and multiplicative interactions with hypertension (P < 0.05). The RERIs (95% CIs) of the additive interaction are −0.93 (−1.882–0.044), 1.394 (0.38–2.407), 0.752 (0.354–1.151) and 0.575 (0.086–1.065), respectively. The HRs (95% CIs) of the multiplicative interaction terms were 0.498 (0.272–0.911), 4.218 (1.230–14.464), 2.423 (1.437–4.086) and 1.701 (1.016–2.848), respectively. CONCLUSION: High concentration of HDL-C reduces the impact of hypertension on IS, while the high concentration of Non-HDL-C, TC/HDL-C, and TG/HDL-C positively interact with hypertension affecting the incidence of IS. This study provides useful evidence for the combined effects of dyslipidemia and hypertension in predicting IS.