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IMPORTANCE Ischemic stroke is associated with increased risk of dementia, but the association of stroke severity and recurrence with risk of impaired cognition is not well known.OBJECTIVE To examine the risk of dementia after incident ischemic stroke and assess how it differed by stroke severity and recurrence. DESIGN, SETTING, AND PARTICIPANTSThe Atherosclerosis Risk in Communities (ARIC) study is an ongoing prospective cohort of 15 792 community-dwelling individuals from 4 US states (Mississippi, Maryland, Minnesota, and North Carolina). Among them, 15 379 participants free of stroke and dementia at baseline (1987 to 1989) were monitored through 2019. Data were analyzed from April to October 2021. Associations between dementia and time-varying ischemic stroke incidence, frequency, and severity were studied across an average of 4.4 visits over a median follow-up of 25.5 years with Cox proportional hazards models adjusted for sociodemographic characteristics, apolipoprotein E, and vascular risk factors.EXPOSURES Incident and recurrent ischemic strokes were classified by expert review of hospital records, with severity defined by the National Institutes of Health Stroke Scale (NIHSS; minor, Յ5; mild, 6-10; moderate, 11-15; and severe, Ն16).MAIN OUTCOMES AND MEASURES Dementia cases adjudicated through expert review of in-person evaluations, informant interviews, telephone assessments, hospitalization codes, and death certificates. In participants with stroke, dementia events in the first year after stroke were not counted.RESULTS At baseline, the mean (SD) age of participants was 54.1 (5.8) years, and 8485 of 15 379 participants (55.2%) were women. A total of 4110 participants (26.7%) were Black and 11 269 (73.3%) were White. A total of 1378 ischemic strokes (1155 incident) and 2860 dementia cases were diagnosed 1 year or more after incident stroke in participants with stroke, or at any point after baseline in participants without stroke, were identified through December 31, 2019. NIHSS scores were available for 1184 of 1378 ischemic strokes (85.9%). Risk of dementia increased with both the number and severity of strokes. Compared with no stroke, risk of dementia by adjusted hazard ratio was 1.76 (95% CI, 1.49-2.00) for 1 minor to mild stroke, 3.47 (95% CI, 2.23-5.40) for 1 moderate to severe stroke, 3.48 (95% CI, 2.54-4.76) for 2 or more minor to mild strokes, and 6.68 (95% CI, 3.77-11.83) for 2 or more moderate to severe strokes. CONCLUSIONS AND RELEVANCEIn this study, risk of dementia significantly increased after ischemic stroke, independent of vascular risk factors. Results suggest a dose-response association of stroke severity and recurrence with risk of dementia.

Background: Low levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the low physiologic range, surrogate markers for reduced liver metabolic function, are associated with cerebral hypometabolism, impairment in neurotransmitter production and synaptic maintenance, and a higher prevalence of dementia. It is unknown whether a prospective association exists between low liver enzyme levels and incident dementia. Objective: To determine whether low levels of ALT and AST are associated with higher risk of incident dementia. Methods: Plasma ALT and AST were measured on 10,100 study participants (mean age 63.2 years, 55% female, 22% black) in 1996–1998. Dementia was ascertained from comprehensive neuropsychological assessments, annual contact, and medical record surveillance. Cox proportional hazards regression was used to estimate the association. Results: During a median follow-up of 18.3 years (maximum 21.9 years), 1,857 individuals developed dementia. Adjusted for demographic factors, incidence rates of dementia were higher at the lower levels of ALT and AST. Compared to the second quintile, ALT values <10th percentile were associated with a higher risk of dementia (hazard ratio [HR] 1.34, 95% CI 1.08–1.65). The corresponding HR was 1.22 (0.99–1.51) for AST. Conclusion: Plasma aminotransferases <10th percentile of the physiologic range at mid-life, particularly ALT, were associated with greater long-term risk of dementia, advocating for attention to the putative role of hepatic function in the pathogenesis of dementia.

We consider a stochastic model for the spread of an SEIR (susceptible → exposed → infective → removed) epidemic among a population of individuals partitioned into households. The model incorporates both vaccination and isolation in response to the detection of cases. When the infectious period is exponential, we derive an explicit formula for a threshold parameter, and analytic results that enable computation of the probability of the epidemic taking off. These quantities are found to be independent of the exposure period distribution. An approximation for the expected final size of an epidemic that takes off is obtained, evaluated numerically, and found to be reasonably accurate in large populations. When the infectious period is not exponential, but has an increasing hazard rate, we obtain stochastic comparison results in the case where the exposure period is fixed. Our main result shows that as the exposure period increases, both the severity of the epidemic in a single household and the threshold parameter decrease, under certain assumptions concerning isolation. Corresponding results for infectious periods with decreasing hazard rates are also derived.

This study evaluated the efficacy of self-regulation interventions through the use of drink-specific implementation intentions and drink-specific Go/No-Go training tasks as compensatory strategies to modify inhibitory control to reduce intake of sugar-sweetened beverages (SSB). In a between-subjects randomized manipulation of implementation intentions and Go/No-Go training to learn to inhibit sugary drink consumption, 168 adolescents reporting inhibitory control problems over sugary drinks and foods were recruited from high schools in southern California to participate. Analysis of covariance overall test of effects revealed no significant differences between the groups regarding calories consumed, calories from SSBs, grams of sugar consumed from drinks, or the number of unhealthy drinks chosen. However, subsequent contrasts revealed SSB implementation intentions significantly reduced SSB consumption following intervention while controlling for inhibitory control failure and general SSB consumption during observation in a lab setting that provided SSBs and healthy drinks, as well as healthy and unhealthy snacks. Specifically, during post-intervention observation, participants in the sugar-sweetened beverage implementation intentions (SSB-II) conditions consumed significantly fewer calories overall, fewer calories from drinks, and fewer grams of sugar. No effects were found for the drink-specific Go/No-Go training on SSB or calorie consumption. However, participants in SSB-II with an added SSB Go/No-Go training made fewer unhealthy drink choices than those in the other conditions. Implementation intentions may aid individuals with inhibitory (executive control) difficulties by intervening on pre-potent behavioral tendencies, like SSB consumption.