Our recent work supports that anxiety and depression are prevalent among Irish older adults with and without non-communicable disease, and that regular physical activity is associated with lower odds of these mental health problems. However, physical activity is critically lacking from mental health policy. Little is known about how much physical activity is beneficial (i.e., optimal dose) or the factors that influence how and in whom activity improves mental health. There currently are no decision models to guide integration and implementation of physical activity prescription into mental health policy and practice. Thus, existing data from The Irish Longitudinal Study on Ageing will be utilized to characterize the optimal physical activity dose for anxiety and depression and biopsychosocial profiles that most strongly predict meeting optimal dose and the positive, negative, or null associations between meeting optimal dose and mental health among Irish older adults with and without non-communicable disease. Linear and logistic mixed-effects models will identify optimal dose among older adults with and without non-communicable diseases. Latent transition analysis will classify participants based on meeting optimal dose and mental health status at each time point. Latent growth modeling will estimate trajectories of change in physical activity and mental health within each latent class. Binomial and hierarchical logistic regression will identify statistically significant modifiable and non-modifiable biopsychosocial predictors. Latent growth modeling will estimate trajectories of change in identified predictors, and multinomial logistic regression will determine the odds that baseline values and change in these factors accurately predict meeting optimal dose and positive, negative, or no associations between meeting optimal dose and mental health. Using the most effective physical activity messaging, these findings will be translated into enhanced physical activity guidelines for mental health and a decision model comprised of factors to be modified to improve mental health through prescription of physical activity.
