The relationship between change in cardiovascular health and rate of cognitive decline: a population-based study

Abstract

Introduction: Vascular risk factors in midlife have been associated with accelerated age-related cognitive decline. However, associations with old-age cardiovascular health are less clear cut and sometimes opposite associations have been observed. The objective of this study was to examine whether change in cardiovascular health, measured using the Life's Simple 7 (LS7) score, is associated with rate of cognitive change in older adults. Methods: We included 1133 participants aged ≥60 years from the Swedish National Study on Aging and Care-Kungsholmen (SNAC-K), who underwent repeated neuropsychological testing (episodic memory, semantic memory, verbal fluency, and perceptual speed) across up to 15 years. LS7, assessed at baseline and at the 6-year follow-up, was composed of seven cardiovascular health metrics (smoking, diet, physical activity, body mass index, plasma glucose, total serum cholesterol, and blood pressure). Change in LS7 was calculated as the difference between baseline and 6 years (range -5 to +8 points). Individuals were categorized into “worse” (-5 to 2 points), “same” (-1 to 1 point), or “improve” (2 to 8 points). Linear mixed-effect models were used to examine change in cognitive performance as a function of LS7 change categories. Results: On average, participants slightly improved (M = 0.3, SD = 1.6) their cardiovascular health from baseline to the 6-year follow-up. Participants were classified as “same” (67.1 %), “improve” (21.0 %), and “worse” (11.8 %). The proportion of those who improved their LS7 individual items was higher for total cholesterol and diet, while the largest deterioration was observed in glucose and physical activity. Both the worse and improve categories were associated with faster cognitive decline. Age-stratified analyses revealed that worsening of LS7 was clearly associated with faster cognitive decline in the old-old (≥ 78 years), whereas improvement tended to be associated with faster cognitive decline in the young-old (< 78 years) group. Discussion: Change in cardiovascular health in old age may lead to faster cognitive decline. The results stress the importance of monitoring and maintaining good cardiovascular health also in very old adults and to, above all, avoid worsening of vascular risk factors.