Although dementia is for the most part a disease of older people, epidemiological data suggest that the pathological processes leading to the disease start operating many years before the clinical onset.1 2 Hence, there is reason to believe that some risk factors begin to exert their impact as early as midlife. In this issue (see page 1194), Alonso et al present evidence suggesting that exposure to vascular risk factors in midlife is associated with an increased risk of dementia.3 In 11 151 community participants from the Atherosclerosis Risk in the Communities study, vascular risk factors were measured at a mean age of 56 years, and hospitalisations with a diagnosis of dementia were prospectively recorded over a follow-up period averaging 13 years. Presence of diabetes, hypertension and active smoking in midlife were associated with a significantly increased risk of hospitalisation with a diagnosis of dementia. Interestingly, these associations were stronger in individuals aged less than 60 when the vascular risk …