Physical Activity Is Inversely Associated With Severe Intracranial Stenosis in Stroke-Free Participants of NOMAS

Abstract

Background: Although protective in secondary stroke prevention of intracranial arterial stenosis (ICAS), it is uncertain if the benefits of leisure time physical activity (LTPA) extend to asymptomatic ICAS or extracranial carotid stenosis (ECAS). Therefore, we sought to determine LTPA's relationship with ECAS and ICAS in a stroke-free, race-ethnically diverse cohort. Methods: This cross-sectional study included participants from the magnetic resonance imaging substudy of the Northern Manhattan Study, of whom 1274 had LTPA assessments at enrollment. LTPA was represented continuously as metabolic equivalent score (MET-score) and ordinally as model-based cluster analysis (LTPA-cluster), both based on the same LTPA assessments. We evaluated ECAS sonographically using carotid intima-media thickening and number of carotid plaques. ICAS was assessed with time-of-flight magnetic resonance angiograph and defined as ≥50% or ≥70% stenosis. We applied regression analyses to evaluate the association between LTPA with ECAS and ICAS, adjusting for confounders. Results: Of 1274 included participants (mean age 71±9 years; 60% women; 65% Hispanic), the mean MET-score was 10±16 and 60% were in a LTPA-cluster with any activity. Among those with carotid ultrasound (n=1234), the mean carotid intima-media thickening was 0.97±0.09 mm, and 56% of participants had at least one carotid plaque identified. Among those with magnetic resonance angiograph (n=1211), 8% had ≥50% ICAS and 5% had ≥70% ICAS. For ICAS, MET-score was associated with ≥70% ICAS (adjusted odds ratio per unit increase in MET-score [95% CI, 0.97 [0.94-0.99]) but not with ECAS measures (carotid intima-media thickening, adjusted β-estimate per unit increase in MET-score [95% CI], 0.002 [-0.003 to 0.006] or number of plaques, adjusted β-estimate [95% CI], 0.0001 [-0.0001 to 0.0003]). Substituting MET-score with LTPA-clusters replicated the association between ≥70% ICAS and LTPA (adjusted odds ratio per each increased LTPA-cluster [95% CI], 0.83 [0.70-0.99]). Conclusions: In this diverse stroke-free population, we found LTPA most strongly associated with asymptomatic ≥70% ICAS. Given the high-risk nature of ≥70% ICAS, these findings may emphasize the role of LTPA in people at risk for ICAS.