Adverse lipid profile elevates risk for subarachnoid hemorrhage: A prospective population-based cohort study

Abstract Background and aims Studies report that both high and low total cholesterol (TC) elevates SAH risk. There are few prospective studies on high-density lipoproteins (HDL-C) and low-density lipoproteins (LDL-C), and apparently none concerns apolipoproteins A and B. We aimed to clarify the association between lipid profile and SAH risk. Methods The National FINRISK study provided risk-factor data recorded at enrolment between 1972 and 2007. During 1.52 million person-years of follow-up until 2014, 543 individuals suffered from incident hospitalized SAH or outside-hospital-fatal SAH. Cox proportional hazards model was used to calculate the hazard ratios and multiple imputation predicted ApoA1, ApoB, and LDL-C values for cohorts from a time before apolipoprotein-measurement methods were available. Results One SD elevation (1.28 mmol/l) in TC elevated SAH risk in men (hazard ratio (HR) 1.15 (95% CIs 1.00–1.32)). Low HDL-C levels increased SAH risk, as each SD decrease (0.37 mmol/l) in HDL-C raised the risk in women (HR 1.29 (95% CIs 1.07–1.55)) and men (HR 1.20 (95% CIs 1.14–1.27)). Each SD increase (0.29 g/l) in ApoA1 decreased SAH risk in women (HR 0.85 (95% CIs 0.74–0.97)) and men (HR 0.88 (95% CIs 0.76–1.02)). LDL-C (SD 1.07 mmol/l) and ApoB (SD 0.28 g/l) elevated SAH risk in men with HR 1.15 (95% CIs 1.01–1.31) and HR 1.26 (95% CIs 1.10–1.44) per one SD increase. Age did not change these findings. Conclusions An adverse lipid profile seems to elevate SAH risk similar to its effect in other cardiovascular diseases, especially in men. Whether SAH incidence diminishes with increasing statin use remains to be studied.