The health status: the ignored risk factor in dementia incidence. NEDICES cohort

Background The causes of the dementia decrease in affluent countries are not well known but health amelioration could probably play a major role. Nevertheless, although many vascular and systemic disorders in adult life are well-known risk factors (RF) for dementia and Alzheimer disease (AD), health status is rarely considered as a single RF. Aim To analyse whether the health status and the self-perceived health (SPH) could be RF for dementia and AD and to discuss its biological basis. Methods We analysed different objective health measures and SPH as RF for dementia and AD incidence in 4569 participants of the NEDICES cohort by means of Cox-regression models. The mean follow-up period was 3.2 (range: 0.03–6.6) years. Results Ageing, low education, history of stroke, and “poor” SPH were the main RF for dementia and AD incidence, whereas physical activity was protective. “Poor” SPH had a hazard ratio = 1.66 (95% CI 1.17–2.46; p = 0.012) after controlling for different confounders. Discussion According to data from NEDICES cohort, SPH is a better predictor of dementia and AD than other more objective health status proxies. SPH should be considered a holistic and biologically rooted indicator of health status, which can predict future development of dementia and AD in older adults. Conclusions Our data indicate that it is worthwhile to include the SPH status as a RF in the studies of dementia and AD incidence and to explore the effect of its improvement in the evolution of this incidence.