To the Editor A recent study¹ reported an increased dementia risk in women using estrogen-only menopausal hormone therapy, which mirrors findings of an earlier study by these authors that demonstrated an increased dementia risk associated with combined menopausal hormone therapy.² These studies have many similar limitations, including confounding by indication, multiple sources of bias, and failure to adjust for factors known to influence dementia risk. In a similar study that adjusted for multiple confounding factors, estrogen-only hormone therapy was associated with a 1.1% decrease in dementia risk per year when used for more than 10 years (hazard ratio, 0.85; 95% CI, 0.76-0.94; P = .003).³