Kidney dysfunction and cerebral microbleeds in neurologically healthy adults

Introduction
Cerebral microbleed (CMB) is a potent risk factor for overt cerebrovascular disease. Although some studies indicated the possible role of renal dysfunction as a risk factor of CMB, the findings could not be generalized. This study aimed to investigate the association between renal dysfunction and cerebral microbleed (CMB) in neurologically healthy adults.
Materials and methods
A total of 2,518 subjects who underwent brain MRI as part of health screening were involved in the study. CMBs were defined as well-demarcated focal areas of low signal intensity with associated blooming on the T2-weighted MRI measuring less than 5mm in diameter. The glomerular filtration rate (GFR) was estimated using the Modification of Diet in Renal Disease formula. Kidney function was classified as normal (≥90), mild (60 to 89.9), moderate (30 to 59.9), and severe (<30 mL/min/1.73 m2) renal dysfunction according to the GFR.
Results
The mean age of the participants was 57.5 ± 8.3 years (ranged 40 to 79), and 1,367 subjects (54.3%) were male. The mean GFR level was 81.5 ± 15.5, and the prevalence of CMB was 4.1% (n = 103). Subjects with CMB demonstrated a higher proportion of moderate-to-severe renal dysfunction than those without CMB (15.5% vs. 5.0%, p < 0.001). In the multivariate logistic regression analysis, moderate-to-severe renal dysfunction showed a significant association with CMB (adjusted odd ratio = 2.63; p = 0.008). Furthermore, a decrease in the GFR level was associated with an increasing trend of the presence of CMB (p for trend = 0.031) and number of CMB lesions (p for trend = 0.003).
Conclusions
Renal dysfunction was significantly associated with the presence of CMB in neurologically healthy adults. More studies are needed to evaluate if treatment of kidney disease and risk factor modification may prevent further progress of CMB.