Author response: Prevalence of and risk factors for cerebral microbleeds in a general Japanese elderly community

We thank Dr. Vilanilam and colleagues for the comment on our article.¹ Our cross-sectional study showed a significant association of hypertension with not only deep/infratentorial cerebral microbleeds (CMBs) but also lobar CMBs. Among the 123 patients with lobar CMBs, 67 had microbleeds in cerebral lobes only (strictly lobar CMBs) and 56 had microbleeds in both lobar and deep/infratentorial regions (mixed CMBs). In Table 5 of the original article,¹ the multivariable-adjusted odds ratio (OR) of hypertension for the presence of lobar CMBs was 1.89 (95% confidence interval [CI] 1.09–3.28; p = 0.02). Since this analysis did not distinguish mixed CMBs from lobar CMBs, we performed the sensitivity analysis for strictly lobar CMBs, defined as lobar CMBs without deep/infratentorial CMBs, and observed a similar association (OR 2.12; 95% CI 1.00–4.50; p = 0.04) (table e-1, links.lww.com/CPJ/A24).¹ Our findings suggest that hypertension contributes to the development of lobar CMBs regardless of the presence of deep/infratentorial CMBs. Cerebral amyloid angiopathy (a major cause of lobar CMBs) and hypertensive angiopathy may coexist in lobar CMBs.² In addition, hypertension and cerebral amyloid angiopathy are likely to contribute synergistically to the development of lobar CMBs.³ Further neuropathologic and experimental studies are necessary to clarify the pathologic mechanisms for the development of lobar CMBs.