White matter hyperintensities, hot flushes and estrogen--are they related?

White matter hyperintensities (WMH) are areas of high intensity observed in brain MRI scans. They are usually seen in normal aging but also in a number of neurological and psychiatric disorders. One of the underlying mechanisms is ischemia, expressed as small vessel disease. Since the volume of WMH may correlate with cognition, and an ongoing debate links postmenopausal hormone therapy with stroke and a decline in certain cognitive domains, several MRI studies have addressed this potential association. Two major randomized, placebo-controlled trials - WHIMS and KEEPS, the first including elderly women and the second recruiting recently menopausal women, did not demonstrate any safety concerns in this respect in hormone users.