Gabriel, Kelley Pettee

Introduction: The prevalence of nonalcoholic fatty liver disease (NAFLD) in US adults is over 25%, yet the etiology of lifestyle factors in the development of NAFLD remains understudied. We examined the independent and joint associations among aerobic physical activity (PA) intensity (moderate, vigorous) and PA type (aerobic, muscle strengthening), television viewing (TV), and odds of NAFLD. Hypothesis: Higher levels of aerobic and muscle strengthening PA are associated with lower odds of NAFLD, and higher levels of TV are associated with higher odds of NAFLD. Methods: We analyzed data from Year 25 of the CARDIA cohort study. Our exposures (moderate and vigorous aerobic and muscle strengthening PA, TV; hr/wk) were assessed using validated questionnaires. Our outcome (NAFLD) was measured using non-contrast computed tomography. We constructed multivariable logistic regression models to examine the independent and joint associations between PA (moderate or vigorous aerobic and strength), TV, and odds of NAFLD. Covariates were sex, age, race, study center, education, diet, smoking status, alcohol consumption, and waist circumference. Results: 2726 participants (648 with NAFLD) were analyzed (mean (SD) age, 50.1 (3.6) years; 49% Black; 43% male). Fully adjusted odds ratios per IQR-standardized continuous PA and TV were: moderate aerobic PA (IQR = 4.3), 0.93 (95% CI, 0.81-1.07); vigorous aerobic PA (IQR = 1.9), 0.63 (95% CI, 0.55-0.73); muscle strengthening PA (IQR = 3.3), 0.80 (95% CI, 0.07-0.92); and TV (IQR = 14.0), 1.20 (95% CI, 1.10-1.32). Only vigorous aerobic PA remained statistically significant after waist circumference adjustment, 0.83 (95% CI, 0.70-0.98). A PA-TV index model (Figure) indicated the combination of higher vigorous aerobic and muscle strengthening PA and lower TV resulted in an odds ratio of 0.23 (95% CI, 0.15-0.37). Conclusion: Concurrent higher levels of vigorous aerobic PA (≥2 hr/wk), muscle strengthening PA (≥2 hr/wk), and lower levels of TV (<7 hr/wk) were associated with 77% lower odds of NAFLD.

AbstractIntroductionSlower mobility is associated with mild cognitive impairment (MCI) and dementia. We examined the interaction of endurance with gait speed on prevalent MCI and dementia.MethodsCross‐sectional multinomial regression in the ARIC cohort (n = 2844 participants; 71 to 94 years; 44% men; 18% Black persons) with cognitive status (normal/MCI/dementia), 4 m gait speed, and endurance (2 minute walk [2MW]).ResultsFaster gait speed (up to but not above 1 m/s) and better 2MW were separately associated with lower dementia risk. Good performance in both (2MW = 200 m, gait speed = 1.2 m/s) was associated with 99% lower dementia (Relative Prevalence Ratio [RPR] = 0.01 [95% CI: 0.0 to 0.06]) and 73% lower MCI, RPR = 0.27 (0.15 to 0.48) compared to poor performance in both (2MW = 100 m, gait speed = 0.8 m/s). Models incorporating a gait speed‐by‐2MW interaction term outperformed gait speed‐only models (P < .001).DiscussionGait speed relationships with dementia diminish at faster gait speeds. Combining endurance with gait speed may yield more sensitive markers of MCI and dementia than gait speed alone.

AbstractIntroductionMotoric cognitive risk (MCR), a clinical syndrome characterized by slow gait speed and subjective cognitive complaints, has been associated with dementia risk. The neuropathological features underlying MCR remain poorly understood.MethodsThe Atherosclerosis Risk in Communities (ARIC) community‐based cohort study classified participants using standardized criteria as MCR+/– and mild cognitive impairment (MCI)+/– at study baseline (2011–2013). We examined the 5‐year dementia risk and baseline brain structural/molecular abnormalities associated with MCR+ and MCI+ status.ResultsOf 5023 nondemented participants included, 204 were MCR+ and 1030 were MCI+. Both MCR+ and MCI+ participants demonstrated increased dementia risk. The pattern of structural brain abnormalities associated with MCR+ differed from that of MCI+. Whereas MCI+ was associated with comparatively smaller volumes in brain regions vulnerable to Alzheimer's disease pathology, MCR+ status was associated with smaller volumes in frontoparietal regions and greater white matter abnormalities.DiscussionMCR may represent a predementia syndrome characterized by prominent white matter abnormalities and frontoparietal atrophy.

Abstract Introduction We tested the hypotheses that higher levels of and persistence of midlife leisure‐time physical activity (LTPA) are associated long‐term with lower cognitive decline and less incident dementia. Methods A total of 10,705 participants (mean age: 60 years) had LTPA (no, low, middle, or high) measured in 1987‐1989 and 1993‐1995. LTPA was assessed in relation to incident dementia and 14‐year change in general cognitive performance. Results Over a median follow‐up of 17.4 years, 1063 dementia cases were observed. Compared with no LTPA, high LTPA in midlife was associated with lower incidence of dementia (hazard ratio [95% confidence interval], 0.71 [0.61, 0.86]) and lower declines in general cognitive performance (−0.07 standard deviation difference [−0.12 to −0.04]). These associations were stronger when measured against persistence of midlife LTPA over 6 years. Discussion LTPA is a readily modifiable factor associated inversely with long‐term dementia incidence and cognitive decline.