The largest prospective cohort study to report associations of testosterone and SHBG with dementia outcomes is the United Kingdom (UK) Biobank, in which 159,411 community-dwelling men, aged 50–73 years, were followed for 7 years, with 826 men developing dementia of whom 288 were classified as having dementia due to Alzheimer disease [13]. The gene discussed is SHBG; the disease is early-onset autosomal dominant Alzheimer disease.