Epidemiologic studies of modifiable factors associated with cognition and dementia: systematic review and meta-analysis.

BACKGROUND: Cognitive impairment, including dementia, is a major health concern with the increasing aging population. Preventive measures to delay cognitive decline are of utmost importance. Alzheimer's disease (AD) is the most frequent cause of dementia, increasing in prevalence from <1% below the age of 60 years to >40% above 85 years of age. METHODS: We systematically reviewed selected modifiable factors such as education, smoking, alcohol, physical activity, caffeine, antioxidants, homocysteine (Hcy), n-3 fatty acids that were studied in relation to various cognitive health outcomes, including incident AD. We searched MEDLINE for published literature (January 1990 through October 2012), including cross-sectional and cohort studies (sample sizes > 300). Analyses compared study finding consistency across factors, study designs and study-level characteristics. Selecting studies of incident AD, our meta-analysis estimated pooled risk ratios (RR), population attributable risk percent (PAR%) and assessed publication bias. RESULTS: In total, 247 studies were retrieved for systematic review. Consistency analysis for each risk factor suggested positive findings ranging from ~38.9% for caffeine to ~89% for physical activity. Education also had a significantly higher propensity for "a positive finding" compared to caffeine, smoking and antioxidant-related studies. Meta-analysis of 31 studies with incident AD yielded pooled RR for low education (RR = 1.99; 95% CI: 1.30-3.04), high Hcy (RR = 1.93; 95% CI: 1.50-2.49), and current/ever smoking status (RR = 1.37; 95% CI: 1.23-1.52) while indicating protective effects of higher physical activity and n-3 fatty acids. Estimated PAR% were particularly high for physical activity (PAR% = 31.9; 95% CI: 22.7-41.2) and smoking (PAR% = 31.09%; 95% CI: 17.9-44.3). Overall, no significant publication bias was found. CONCLUSIONS: Higher Hcy levels, lower educational attainment, and decreased physical activity were particularly strong predictors of incident AD. Further studies are needed to support other potential modifiable protective factors, such as caffeine.

Past blood alcohol concentration and injury in trauma center: propensity scoring.

BACKGROUND: Evidence linking alcohol use to injury outcomes remains inconclusive, with prehospital and police department-based studies showing negative effects and hospital-based studies showing no effect or better outcomes. OBJECTIVE: The purpose of this study was to examine the relationship of blood alcohol concentration (BAC) with injury characteristics and outcomes among trauma patients admitted to a major teaching hospital. In an effort to mitigate selection and confounding bias, propensity scoring methodology was applied, by which trauma patients were randomly assigned to high- and low-BAC groups. METHODS: Electronic medical records were retrospectively reviewed for a period of 8 months. Of 1057 patients whose BAC was determined, 667 had BAC ≤ 0.08 g/dL and 390 had BAC > 0.08 g/dL. Injury characteristics were defined as injury type, injury location, and trauma level. Injury outcomes were defined as hospitalization, length of hospital stay, and in-hospital death. Adjusted odds ratios (aOR) and their 95% confidence intervals (CI) were calculated using multivariate logistic regression models and propensity scoring was applied. RESULTS: A positive relationship was observed between BAC and unintentional injury (aOR = 1.08; 95% CI 1.01-1.17). Although injuries of the extremities were less likely to occur in patients with high BAC (aOR = 0.88; 95% CI 0.80-0.98), head injury was positively associated with high BAC (aOR = 1.27; 95% CI 1.14-1.42). Also, Level I trauma patients had nearly 60% greater odds of having a high BAC than Level II trauma patients. CONCLUSIONS: A high alcohol level in the blood appears to be predictive of more unintentional injury, head injury, and Level I trauma activation and less injuries in extremities.