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Context:The stress responses of the hypothalamicpituitary-adrenal axis can produce adverse effects on the brain. Previous studies have concluded that an elevated level of cortisol is a risk factor for cognitive dysfunction and decline in aging but have been limited by sex exclusion, restricted cognitive batteries, and small sample sizes.Objective: To examine associations among salivary cortisol metrics and cognitive domain scores in an urban adult population.Design, Setting, and Participants: A crosssectional analysis was conducted using data from a longitudinal study involving 1140 Baltimore, Maryland, residents aged 50 to 70 years. Four salivary cortisol samples were obtained from 967 participants across 1 study visit (before, during, and after cognitive testing as well as at the end of the visit) from which 7 cortisol metrics were created. We examined associations of cortisol metrics with cognitive performance using multiple linear regression. Main Outcome Measures:Performance on 20 standard cognitive tests was measured and combined to form summary measures in 7 domains (language, processing speed, eye-hand coordination, executive functioning, verbal memory and learning, visual memory, and visuoconstruction).Results: Higher levels of pretest and mean cortisol as well as the area under the curve of cortisol over the study visit were associated with worse performance (PϽ.05) in 6 domains (language, processing speed, eye-hand coordination, executive functioning, verbal memory and learning, and visual memory). For instance, an interquartile range increase in the area under the curve was equivalent to a decrease in the language score expected from an increase in 5.6 (95% confidence interval, 4.2-7.1) years of age.Conclusions: Elevated cortisol was associated with poorer cognitive function across a range of domains in this large population-based study. We believe the findings are consistent with the hypothesis that hypothalamic-pituitaryadrenal axis dysregulation may be a risk factor for poorer cognitive performance in older persons. Psychiatry. 2007;64(7):810-818 Arch Gen

Background Elevated cortisol may be a risk factor for cognitive decline in aging. Genetic factors may influence individual vulnerability to the adverse effects of stress on cognitive function in aging. Methods We investigated whether gene-environment interaction by apolipoprotein E genotype and cortisol predicted cognitive performance in an urban population of older adults. A cross-sectional analysis of data was conducted from a population-based sample of 50–70 year old men and women. Cognitive performance, salivary cortisol levels, and APOE genotype was assessed in 967 subjects. Performance on 20 standard cognitive tests was assessed and combined to form seven summary domain scores (language, processing speed, eye-hand coordination, executive functioning, verbal memory and learning, visual memory and learning, visuoconstruction). Results In adjusted models, while higher levels of cortisol were associated with worse cognitive scores, the slopes of the adverse relations were steeper in persons with at least one ε4 allele. Effect sizes were large: for example, the effect of having one ε4 allele and cortisol area under curve > 75th percentile was equivalent to a decrease in language score expected from an increase in 8.0 (95% CI: 1.7, 14.4) years of age, while having two ε4 alleles and cortisol area under curve > 75th percentile was equivalent to an increase of 33.4 (14.8, 52.0) years of age. Conclusion These data indicate that APOE genotype may modify relations of cortisol with cognitive functioning, and suggest that the ε4 allele increases vulnerability of the aging brain to the adverse effects of stress.

Before the 1970s, today's older Americans were exposed to high levels of lead in the environment. The authors previously reported that lifetime cumulative lead dose was associated with lower cognitive test performance in older adults. Experiments suggest that environmental stress may intensify the detrimental influence of lead. No large, population-based studies of this question have been done. The authors evaluated whether cross-sectional associations of tibia lead with cognitive function were modified by neighborhood psychosocial hazards in the Baltimore Memory Study (2001-2005), a longitudinal cohort study of determinants of cognitive decline. Tibia lead was measured via (109)Cd-induced K-shell X-ray fluorescence. Neighborhood psychosocial hazards were measured independently of study subjects. Complete data were available among 1,001 demographically diverse adults aged 50-70 years, randomly selected from 65 contiguous neighborhoods in Baltimore City. Hierarchical mixed-effects regression models showed that neighborhood psychosocial hazards exacerbated the adverse associations of tibia lead in 3 of 7 cognitive domains after adjustment for age, sex, race/ethnicity, education, testing technician, and time of day (language, P = 0.039; processing speed, P = 0.067; executive functioning, P = 0.025). The joint occurrence of environmental stress and lead exposure across the life span may partially explain persistent racial/ethnic and socioeconomic disparities in cognitive function in late life.

This report presents results from a study on the bacterial diversity of cigarette brands collected from military personnel during the U.S. Army's investigation of a series of cases of acute eosinophilic pneumonitis in military personnel deployed in Operation Iraqi Freedom. Eight species of Bacillus, including five new species, and one new species of Kurthia were isolated from the cigarettes. Some of these species have been identified elsewhere as causes of hypersensitivity pneumonitis and other respiratory syndromes. All of the isolates were facultative anaerobes, and many displayed mucoid growth under anaerobic conditions. In addition, many isolates also displayed the ability to form surface biofilms under liquid culture. Although biofilm formation and mucoid growth were not correlated, the former was found to be much more pronounced under anaerobic conditions as opposed to aerobic ones. The implications of these findings are discussed.