Relationships of handgrip strength with the presence of cerebral microbleeds and platelet count in older Japanese adults

Introduction: Lower handgrip strength is a manifestation of sarcopenia and frailty, and has been reported to be associated with cerebral microbleeds (CMBs), which appear on T2(*)-weighted magnetic resonance scans as low-intensity spots. However, the underlying mechanism is unknown. We hypothesized that vascular endothelial injury could be the common factor in loss of handgrip strength and CMBs. We aimed to clarify the relationship between handgrip strength and CMBs, with reference to a marker of vascular repair capability. Materials and Methods: We conducted a cross-sectional study of 95 60- to 87-year-old Japanese people who underwent brain magnetic resonance imaging in 2016–2017. Baseline information was obtained by trained interviewers regarding the age, sex, smoking status, nutrient intake, cognition, medical history, education, and household income of the participants. Physical activity was assessed using a tri-axial accelerometer. We used the Fried frailty phenotype definition. Multivariable linear regression analysis was performed. Results: Handgrip strength was independently associated with the presence of CMB after adjustment for age, sex, body mass index, classical cardiovascular risk factors, protein intake, and daily activity (B = −3.43, p = 0.027). This association was shown in participants with a low (B = −4.05, p = 0.045) but not high platelet count (B=−2.23, p = 0.479). Frailty was also independently associated with the presence of CMB after adjustment for confounders (B = 0.57, p = 0.014). Although this association was not present in participants a high platelet count, there was a positive trend in those with a low platelet count (B = 0.50, p = 0.135). Conclusions: Platelet count, a marker of vascular repair capability, appears to modify the relationship between handgrip strength and CMBs.