Association of elevated lipoprotein(a) levels with ischemic stroke in young patients - a systematic review and meta-analysis

Introduction: Lipoprotein(a) [Lp(a)] is an established independent causal risk factor for cardiovascular disease and atherosclerosis. However, its association with young-onset ischemic stroke is not well-established. A systematic review and meta-analysis was performed to investigate the association of elevated Lp(a) with young ischemic stroke. Methods: Four electronic databases: PubMed (MEDLINE), EMBASE, Scopus and Cochrane Library were systematically searched, profiling studies from inception till 6 Mar 2024. We included studies investigating the relationship between stratified Lp(a) levels and young ischemic stroke. We compared the odds of young stroke patients (age <65 years) having elevated Lp(a) compared to age-matched controls without stroke or transient ischemic attack. Results: Five case-control studies comprising a total of 1345 patients were included; 57.7 % (776/1345) were females, with a mean age of 41.5 years. Among them, 22.5 % (264/1171) were smokers. Additionally, 16.8 % (197/1171) had hypertension, 5.9 % (69/1171) had diabetes, and 29.2 % (284/971) had hyperlipidemia. Young stroke patients were more likely to have high Lp(a) level than age-matched controls (OR 1.61, 95 %CI 1.24-2.10). Four studies defined a high Lp(a) level as >= 30mg/dL, whilst one study used a Lp(a) level of >23.2mg/dL as the cut-off. A sensitivity analysis excluding this study showed that young stroke patients were still more likely to have Lp(a) >= 30mg/dL than controls (OR 1.43, 95 %CI 1.08-1.88). Conclusion: Young stroke patients are more likely to have elevated Lp(a) compared to age-matched controls, suggesting an association between elevated Lp(a) and young stroke. Further research is warranted to evaluate the causal relationships between Lp(a) and young-onset ischemic stroke, as well as to conduct a cost-benefit analysis of Lp(a) screening in young adults as part of a primary prevention strategy.