Sex-specific association between body mass index and cerebral microbleed progression in adults aged 50-85 years

Abstract

Background and purpose: Previous studies have demonstrated sex differences in the association between body mass index (BMI) and hemorrhagic stroke. Cerebral microbleed (CMB) is a clinically important marker of bleeding-prone microangiopathy, which is associated with a risk of hemorrhagic stroke. No study has evaluated sex differences in the relationship between BMI and CMB. In this longitudinal study, we aimed to conduct sex-stratified analyses to assess whether sex modifies the effect of BMI on CMB progression. Methods: The database of the CHALLENGE study (Comparison Study of Cilostazol and Aspirin on Changes in Volume of Cerebral Small Vessel Disease White Matter Changes), which enrolled patients aged 50-85 years with cerebral small vessel disease, was analyzed. Of the 256 subjects, 189 who underwent a 2-year follow-up brain MRI scan were included in the analysis. We used a generalized linear mixed model with a negative binomial distribution to assess the association between BMI and the 2-year change in CMB count, and conducted sex-stratified analyses to account for potential sex-specific effects. Results: A total of 65 men and 124 women were analyzed. In the sex-stratified negative binomial model, a significant association was observed in women but not in men. In women, each 1 kg/m(2) increase in BMI was significantly associated with a decrease in the 2-year change in the number of total CMBs after adjustment for age and baseline CMB count [beta = -0.120, 95% confidence interval (CI): -0.202 to -0.037, p = 0.005]. When CMBs were categorized into lobar and deep/infratentorial regions, significant associations were observed for both lobar (beta = -0.114, 95% CI: -0.213 to -0.015, p = 0.024) and deep/infratentorial CMBs (beta = -0.123, 95% CI: -0.222 to -0.023, p = 0.015). By contrast, no significant associations were identified between BMI and the 2-year change in CMB counts in men (all p > 0.05). Conclusion: Higher BMI in later life was associated with less progression of CMBs in women, but not in men.