The consensus on neurodegenerative diseases, particularly Alzheimer’s disease, is coming to be that these varied age-related conditions have deep roots. People on the road to developing Alzheimer’s most likely have a biochemistry that is distinguishable from their peers ten or twenty years prior to the emergence of evident symptoms, and perhaps even earlier. The open access paper noted here discusses some of the evidence that supports this viewpoint.
Along these lines, I think that we will see a sizable growth in efforts to find early biomarkers that predict later development of neurodegeneration, building on the work of recent years in which the first few comparatively non-invasive approaches have appeared in the literature. It remains unclear at this time as to the degree to which lifestyle choices matter in these considerations. While there are certainly arguments for Alzheimer’s risk to be increased by being sedentary and overweight, one of the biggest questions regarding Alzheimer’s is why only some people with these risk factors go on to develop the condition rather than the majority one might expect in the case of a strong causal relationship.