Brain lesions on MRI and endogenous sex hormones in elderly men

We investigated the association between MRI detected brain lesions and levels of endogenous sex hormones in Japanese–American men aged 74–95 years. Logistic regression was used to estimate the association (OR (95% CI)) of MRI outcome with tertiles of bioavailable testosterone, 17β estradiol and sex hormone binding globulin (SHBG). There was a significantly increased risk for cerebral atrophy in the highest tertile of testosterone (3.1 (1.2–7.8)) compared to the lowest. We also found that men with the highest estradiol had a higher risk of lacunes (1.92 (1.1–3.2)). These relationships did not change with adjustment for the other sex hormones, cardiovascular risk factors, or other brain lesions. In contrast, men with the highest SHBG had a lower risk both of cerebral atrophy and lacunes, after adjusting for sex hormones and cardiovascular risk factors. There were no associations between sex hormones and hippocampal atrophy, white matter lesions, and large infarcts. Because the levels of hormone were measured close in time to the acquisition of the MRI, these associations may reflect neurodegeneration in brain regions regulating hormone levels.