Chronic kidney disease defined by 24-hour urinary albumin and silent brain infarction in community-dwelling older adults

Albuminuria is a well-established marker of chronic kidney disease (CKD) and a known risk factor for stroke. However, its relationship with silent brain infarction (SBI), a key imaging marker of cerebral small vessel disease (CSVD), remains unclear. Importantly, no prior study has examined this association using quantitative 24-h urine collection. We conducted a cross-sectional study of 296 community-dwelling older adults (mean age: 68.7 years) who underwent brain magnetic resonance imaging (MRI) and comprehensive health screening, including 24-h urine sampling. SBI was identified in 26 participants (8.8%), and albuminuria (≥ 30 mg/day) in 30 (10.1%). In multivariable logistic regression (Model 1), age and hypertension were significantly associated with SBI, while estimated glomerular filtration rate was not. In Model 2, which included urinary indices, log-transformed 24-h urinary albumin was independently associated with SBI (odds ratio [OR]: 3.30; 95% confidence intervals [CI]: 1.38–7.87), and the association with hypertension lost significance. Sensitivity analyses excluding three macroalbuminuria cases produced similar results. Moderately increased albuminuria (30–299 mg/day), measured via 24-h urine collection, may serve as an early indicator of SBI due to CSVD, even in individuals with preserved renal function.