The potential for dementia risk reduction may differ regionally within and between countries due to existing differences in risk factor distributions and demographic characteristics. A recent publication in the Journal of Prevention of Alzheimer's Disease set out to estimate differences in modifiable dementia risk factors across 19 Italian regions. For this study, researchers from the Italian National Institute of Health and the University of Modena and Reggio Emilia calculated a metric called the population attributable fraction. This metric represents the proportion of dementia cases attributable to a certain risk factor and is commonly used to quantify preventative potential, for instance, in the report of the Lancet Commission for Dementia Prevention, Intervention, and Care. Population attributable fractions take into account the prevalence of a given risk factor, the strength of association with dementia and the overlap between different risk factors.
The researchers included 11 of the 12 risk fac-tors presented in the Lancet Commission report, namely: lower education, hearing loss, traumatic brain injury, hyper-tension, alcohol consumption, obesity, smoking, depression, social isolation, physical inactivity, diabetes, and air pollution. They found that, at the national level, 39.6% of dementia cases were attributable to these risk factors, with hyperten-sion and physical inactivity carrying the most weight. They also observed that in the southern regions, the proportion of potentially preventable cases was higher than in the northern regions. Estimating the effect of a partial reduction in risk factors, the researchers suggest that a 10% reduction across risk factors could correspond to nearly 55,000 dementia cases potentially prevented in Italy. When assessing the alignment between regional dementia strategies and preventative potential, they found that in some regions, there is a mis-match between prevention policies and the actual opportunity for risk reduction. The full study can be read here (open access): https://pubmed.ncbi.nlm.nih.gov/39809612/
