Inverse association between dietary fiber intake and asymptomatic intracranial atherosclerotic stenosis in older adults: The YAHABA Study

Abstract Background Intracranial atherosclerosis is a major cause of ischemic stroke. Asymptomatic intracranial atherosclerotic stenosis (ICAS) represents a subclinical and potentially modifiable stage preceding ischemic stroke, yet the nutritional factors associated with asymptomatic ICAS remain poorly defined. This study aimed to identify dietary factors associated with asymptomatic ICAS in community-dwelling older adults. Methods This cross-sectional, population-based study included 962 Japanese adults aged ≥65 years from the Yahaba Active Aging and Healthy Brain study, conducted in Yahaba town, Japan, between July 2016 and July 2017. Asymptomatic ICAS was defined as ≥50% intracranial arterial stenosis evaluated by magnetic resonance angiography (MRA) without a history of stroke or transient ischemic attack. All participants underwent dietary assessment using a food frequency questionnaire. We examined the association between nutritional factors and ICAS using multivariable logistic regression models with adjustment for age, sex, hypertension, dyslipidemia, diabetes mellitus, body mass index, smoking, and alcohol use. Results After excluding 43 participants who could not undergo brain MRI, 2 with inadequate vascular imaging on MRA, 57 with a history of stroke, and 10 with missing data, 850 participants were included in the analysis. The mean age was 73.4 ± 6.5years, and 52% were female. ICAS was identified in 135 participants (15.9%) on MRA. Participants in the highest quartile of dietary fiber intake had significantly lower odds of ICAS than those in the lowest quartile (OR, 0.45; 95% CI, 0.26–0.80) after adjusting for vascular risk factors. Participants in the highest quartile of potassium intake also had lower odds of ICAS than those in the lowest quartile (OR, 0.49; 95% CI, 0.27–0.89). When dietary fiber and potassium were simultaneously included in the multivariable analysis as continuous variables, neither remained significant, with moderate collinearity (variance inflation factor, 4.16). Conclusions Higher dietary fiber intake was inversely associated with asymptomatic ICAS among community-dwelling older Japanese adults. Potassium intake also showed an inverse association, although this relationship was less consistent after accounting for collinearity with dietary fiber.