Life's Simple 7 and Global- and Domain-Specific Cognitive Function in an Older Adult Population
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Abstract
The American Heart Association Life's Simple 7 (LS7), a metric that classifies cardiovascular health using modifiable risk factors, has been reported to be associated with cognitive function. However, the assessment of cognitive function in prior studies has been limited to relatively crude global measures. We hypothesized that greater LS7 scores at baseline are associated with less cognitive decline and lower incidence of dementia and Alzheimer's. Using data from the core Health and Retirement Study survey (2012-2018), 2013 Health Care and Nutrition Questionnaire and enhanced face-to-face interviews we will evaluate cognitive scores in relation to LS7. The participants included in this analysis (n = 2,753) are greater than 50 years of age without dementia. A global cognitive score was calculated using the combination scores on multiple cognitive tests that include measurements of semantic memory, quantitative reasoning, episodic memory, and executive functioning. Changes in cognitive scores are evaluated based on marginal effects after adjustments for confounding variables. Baseline LS7 scores (0-14) were calculated using information on smoking habits, body mass index, habitual diet, blood pressure, non, physical activity, and hemoglobin a1c. Results were analyzed using linear mixed models fit with random intercepts and the use of Huber-White variance estimates to analyze the results. Knots were introduced to explain non-linear change in respondents. Global cognitive scores in all respondents decreased more between baseline to year two and year two to year four than year four to year six (ΔB-2: -2.796, Δ2-4: -3.362 v. Δ4-6: -1.191). A one unit increase in LS7 score presented a protective effect and slowed the rate of decline by 0.11 unit in global cognitive scores between baseline and year two. The protective effect was lower between year two and four (0.07 units) and non-significant between year four and six. Black respondents did not respond similarly in models than white respondents. A one unit increase in LS7 score increased the rate of decline from baseline to year two and year two to year 4 in black respondents (p<0.001, p<0.05). LS7 scores had no significant interaction with global cognitive scores between year 2 and 6. Serial 7 scores did not significantly change over time in any of the racial categories. A unit increase in LS7 scores showed a marginal protective effect on memory scores from year two to four in all respondents (r=0.03, p<0.001). In white respondents, higher LS7 scores had a protective effect on memory scores (r=0.01, p<0.05). The probability of developing dementia or Alzheimer's over the study period was the highest for males (P = 3.6%) than females (P = 3.3%) and lowest for white, females (P=13%) and highest for black, males (P=15%). Having higher LS7 scores at baseline is associated lower cognitive decline over a 6-year period in white, older adults. LS7 scores at baseline delayed word recall/memory scores over time but not serial 7/executive functioning scores. LS7 scores at baseline are not associated with lower incidence of cognitive impairment and dementia. Findings suggest better habits formed earlier in life have a better protective effect than late-life habits