Is Cognitive Reserve a Determinant of Functional and Mental Health in Older People of the Sardinian Blue Zone? A Mediational Approach

The main purpose of this study was to examine the mediating role of cognitive reserve in the relationship between functional health (expressed through the amount and intensity of performed physical activity objectively assessed using wearable accelerometers) and psychological well-being (i.e., assessed in terms of self-reported depressive signs) of older people living in an area of exceptional longevity, the so-called Sardinian Blue Zone. A further goal was to investigate the impact of gender on the cognitive reserve and physical health of our participants, using global cognitive functioning as a covariate. A battery of tests assessing motor efficiency, cognitive reserve, global cognitive functioning, and self-reported depressive symptoms was individually presented to 120 community dwellers (Mage = 82 years, SD=8.4 years) of the Sardinian Blue Zone. Significant associations were found between cognitive reserve, motor efficiency, and self-reported depressive signs. Moreover, three mediation analyses documented that distinct indexes of cognitive reserve and motor efficiency explain 27.2-31% of the variance in the self-reported depression condition. Following this, it was also found that people with scarce cognitive reserve tended to exhibit significant signs of depression and showed worse motor abilities. In addition, after controlling for the effect of global cognitive functioning, motor efficiency, and cognitive reserve were generally more preserved in males than in females. Overall, these findings suggest that cognitive reserve is a compensatory resource that contributes significantly to the enhancement of health-related quality of life in the last decades of life.