Abstract: The invention relates to gene regulation in ageing, and age-related cognitive decline. The invention, in particular relates to methods for screening a subject for a propensity to develop diseases associated with oxidative stress, and for age-related conditions, by examining the up-regulation and/or down-regulation of at least one gene associated within the central nervous system.

Abstract: Blood cholesterol levels are correlated with production of amyloid ? protein (A?), and are predictors of populations at risk of developing AD. Methods for lowering blood cholesterol levels can be used to decrease production of A?, thereby decreasing the risk of developing AD. The same methods and compositions can also be used for treating individuals diagnosed with AD. Methods include administration of compounds which increase uptake of cholesterol by the liver, such as the administration of HMG CoA reductase inhibitors, administration of compounds which block endogenous cholesterol production, such as administration of HMG CoA reductase inhibitors, administration of compositions which prevent uptake of dietary cholesterol, and administration of combinations of any of these which are effective to lower blood cholesterol levels. Methods have also been developed to predict populations at risk, based on the role of cholesterol in production of A?.