Adapting to dementia in society: a challenge for our lifetimes and a charge for public health.

For the last several decades, Alzheimer's disease (AD) has been widely regarded as a late life event, but is now being redefined as a chronic condition that develops over decades. Concurrently, a preponderance of evidence emerging from basic and clinical research in diverse fields such as cardiovascular, endocrine, and mental health has suggested that the environmental component of clinical AD is not only multifactorial in populations and in individuals, but is also modifiable across the life-course, from conception until death. Re-conceptualizing the environmental component of AD to account for these observations necessitates an approach to brain health that eschews singular, short- and medium-term methodology and instead reflects long-term complexity. Such thinking is consistent with the ecological models of public health, which emphasize the development of community infrastructure that can foster population and individual health over the life-course by minimizing risk through multifaceted, systemic approaches.