Demographics of lipoprotein(a) and stroke: The UK biobank

Lipoprotein(a) [Lp(a)] is associated with ischemic stroke, but the strength of association based on demographic differences remains unclear. We aimed to investigate the association between Lp(a)>125 nmol/L and stroke by age, sex, and racial/ethnic subgroups.

Using data from the UK Biobank, we included 353,309 participants with an Lp(a) measurement without a history of atherosclerotic cardiovascular disease (ASCVD). Stroke was defined as ischemic stroke or hemorrhagic stroke (with subtypes subarachnoid hemorrhage and intracerebral hemorrhage). Cox proportional hazards models were used to evaluate the association between elevated Lp(a) and stroke (ischemic or hemorrhagic), adjusted for ASCVD risk factors, race/ethnicity, lipid lowering therapy, antiplatelet and anticoagulation medications. Outcomes were defined using ICD-10 codes.

The study population consisted of 55.7 % women and 94 % White individuals with average age of 56 years. The median Lp(a) level was 20.9 [IQR 9.5, 61.4] nmol/L and prevalence of Lp(a) >125 nmol/L was 11.1 % (n = 39,067). Over a median follow-up of 13.8 [13.1, 14.5] years, there were 5002 (1.4 %) ischemic strokes and 1462 (0.4 %) hemorrhagic strokes. Lp(a) > 125 nmol/L was associated with increased risk for ischemic stroke (HR 1.12, 95 % CI 1.02-1.22, P = 0.019), but not hemorrhagic stroke (HR 0.95, 95 % CI 0.79-1.13, P = 0.545). The association between Lp(a)>125 nmol/L and ischemic stroke did not vary by age (p-interaction=0.691) or race/ethnicity (p-interaction 0.526) but did vary by sex (p-interaction=0.041) with an association among men (HR 1.20, 95 % CI 1.07-1.36) but not among women.

Lp(a) is independently associated with ischemic stroke, with variation by sex but not age or race/ethnicity. Lp(a) was not significantly associated with hemorrhagic stroke.