Supplementary Material for: Cognition and Incident Dementia Hospitalization: Results from the Atherosclerosis Risk in Communities Study

<b><i>Background/Aims:</i></b> Cognitive decline is a defining feature of dementia. We sought to determine if a single baseline cognitive test score or change in test score over time is more strongly associated with risk of dementia hospitalization. We also sought to compare short- and long-term dementia risk. <b><i>Methods:</i></b> Prospective cohort study of 9,399 individuals from the Atherosclerosis Risk in Communities Study (median 10 years of follow-up). Cognition was assessed at two time points (6 years apart) using three tests: Delayed Word Recall Test (DWRT), Digit Symbol Substitution Test (DSST), and Word Fluency Test. Dementia hospitalizations were determined using ICD-9 codes. <b><i>Results:</i></b> Baseline cognitive test scores were associated with both short-term and long-term risk of dementia. The association of 6-year change in cognitive test score with dementia risk was stronger than that of individual test scores at a single visit [change from highest to lowest tertile, DWRT: hazard ratio = 6.45 (95% confidence interval = 1.80–23.08); DSST: hazard ratio = 10.94 (95% confidence interval = 3.07–38.97)]. <b><i>Conclusions:</i></b> In this community-based population, 6-year changes in cognitive scores were more strongly associated with risk of incident dementia hospitalization than baseline scores, although single DWRT and DSST scores were predictive. Our findings support the contention that cognitive changes may precede clinical dementia by a decade or more

Supplementary Material for: The Metabolic Syndrome and Cognitive Decline in the Atherosclerosis Risk in Communities Study (ARIC)

<b><i>Background:</i></b> Midlife metabolic syndrome (MetS) may impact cognitive health as a construct independently of hypertension, hyperlipidemia and other components. <b><i>Methods:</i></b> 10,866 participants aged 45-64 years at baseline were assessed for MetS and completed cognitive testing at two later time points (3 and 9 years from the baseline visit). <b><i>Results:</i></b> MetS is associated with increased odds of low cognitive performance in the domains of executive function and word fluency, but not with 6-year cognitive decline. Individual MetS components explained this association (hypertension, diabetes, low HDL, elevated triglycerides and increased waist circumference). <b><i>Conclusions:</i></b> A focus on the individual risk factors as opposed to MetS during midlife is important to reduce the incidence of cognitive impairment in later life

Supplementary Material for: Serum Vitamin D Concentrations and Cognitive Change Over 20 Years: The Atherosclerosis Risk in Communities Neurocognitive Study

<b><i>Background/Aims:</i></b> 25-hydroxyvitamin D (25[OH]D) concentrations have been associated with cognitive decline and incident dementia in elderly populations; however, these relationships are susceptible to reverse causation. Less is known about the association of midlife 25(OH)D with long-term cognitive decline. <b><i>Methods:</i></b> This was a prospective cohort study of 13,044 participants (mean age 57 years at baseline) in the Atherosclerosis Risk in Communities Study. 25(OH)D was measured from serum collected at baseline (1990–1992) using liquid chromatography tandem high-sensitivity mass spectrometry. Cognition was assessed using 3 neuropsychological tests at 3 time points, which were combined into a composite cognitive <i>Z</i>-score. Multivariable-adjusted linear mixed-effects models with random intercepts and slopes were used to estimate associations between 25(OH)D and cognitive change over 20 years. <b><i>Results:</i></b> Compared to persons with sufficient 25(OH)D (≥30 ng/mL), those with deficient (< 20 ng/mL) and intermediate (20–< 30 ng/mL) 25(OH)D concentrations had similar cognitive decline in composite cognitive <i>Z</i>-scores (deficient versus sufficient: –0.035 [95% CI –0.104 to 0.033] and intermediate versus sufficient: –0.029 [95% CI –0.080 to 0.023]). <b><i>Conclusions:</i></b> Lower concentrations of 25(OH)D measured in midlife were not significantly associated with more rapid cognitive decline over a 20-year follow-up period. The results of this prospective study are less susceptible to reverse causation than prior studies