Our results indicate that even in the absence of manifest type 2 diabetes mellitus or impaired glucose tolerance, chronically higher blood glucose levels exert a negative influence on cognition, possibly mediated by structural changes in learning-relevant brain areas. Therefore, strategies aimed at lowering glucose levels even in the normal range may beneficially influence cognition in the older population, a hypothesis to be examined in future interventional trials.

No abstract

Background:Mild cognitive impairment (MCI) describes the intermediate state between normal cognitive aging and dementia. Adverse effects of air pollution (AP) on cognitive functions have been proposed, but investigations of simultaneous exposure to noise are scarce.Objectives:We analyzed the cross-sectional associations of long-term exposure to AP and traffic noise with overall MCI and amnestic (aMCI) and nonamnestic (naMCI) MCI.Methods:At the second examination of the population-based Heinz Nixdorf Recall study, cognitive assessment was completed in 4,086 participants who were 50–80 years old. Of these, 592 participants were diagnosed as having MCI (aMCI, n = 309; naMCI, n = 283) according to previously published criteria using five neuropsychological subtests. We assessed long-term residential concentrations for size-fractioned particulate matter (PM) and nitrogen oxides with land use regression, and for traffic noise [weighted 24-hr (LDEN) and night-time (LNIGHT) means]. Logistic regression models adjusted for individual risk factors were calculated to estimate the association of environmental exposures with MCI in single- and two-exposure models.Results:Most air pollutants and traffic noise were associated with overall MCI and aMCI. For example, an interquartile range increase in PM2.5 and a 10 A-weighted decibel [dB(A)] increase in LDEN were associated with overall MCI as follows [odds ratio (95% confidence interval)]: 1.16 (1.05, 1.27) and 1.40 (1.03, 1.91), respectively, and with aMCI as follows: 1.22 (1.08, 1.38) and 1.53 (1.05, 2.24), respectively. In two-exposure models, AP and noise associations were attenuated [e.g., for aMCI, PM2.5 1.13 (0.98, 1.30) and LDEN 1.46 (1.11, 1.92)].Conclusions:Long-term exposures to air pollution and traffic noise were positively associated with MCI, mainly with the amnestic subtype.Citation:Tzivian L, Dlugaj M, Winkler A, Weinmayr G, Hennig F, Fuks KB, Vossoughi M, Schikowski T, Weimar C, Erbel R, Jöckel KH, Moebus S, Hoffmann B, on behalf of the Heinz Nixdorf Recall study Investigative Group. 2016. Long-term air pollution and traffic noise exposures and mild cognitive impairment in older adults: a cross-sectional analysis of the Heinz Nixdorf Recall Study. Environ Health Perspect 124:1361–1368; http://dx.doi.org/10.1289/ehp.1509824

There is increasing evidence that sleep disorders are associated with cognitive decline. We, therefore, examined the cross-sectional association of sleep-disordered breathing (SDB), sleep quality, and three types of sleep complaints (difficulties initiating sleep, difficulties maintaining sleep, and early morning awakening) with mild cognitive impairment (MCI) and its subtypes. A group of 1,793 participants (51% men; 63.8 ± 7.5 years) of the population-based Heinz Nixdorf Recall study (total sample n = 4,157) received a screening for SDB and self-report measures of sleep complaints. Group comparisons were used to compare performances among five cognitive subtests. Multivariate logistic regression models were calculated to determine the association of MCI (n = 230) and MCI subtypes (amnestic MCI, n = 120; non-amnestic MCI, n = 110) with SDB severity levels, poor sleep quality, and sleep complaints. Severe SDB (apnea-hypopnea index ≥30/h, n = 143) was not associated with MCI, amnestic MCI, or non-amnestic MCI. Poor sleep quality was associated with MCI (Odds ratio (OR) = 1.40, 95% confidence interval (CI) = 1.02-2.03; fully adjusted) as well as frequently reported difficulties initiating sleep (OR = 1.94, 1.20-3.14), difficulties maintaining sleep (OR = 2.23, 1.27-4.63), and early morning awakening (OR = 2.30, 1.32-4.00). Severe difficulties initiating sleep (OR = 2.23, 1.21-4.13) and early morning awakening (OR = 2.88, 1.45-5.73) were solely associated with the amnestic MCI subtype, whereas, severe difficulties maintaining sleep (OR = 3.84, 1.13-13.08) were associated with non-amnestic MCI. Our results suggest that poor sleep quality, rather than SDB, is associated with MCI. The selective association of difficulties initiating sleep and early morning awakening with amnestic MCI and of difficulties maintaining sleep with non-amnestic MCI might serve as a marker to improve diagnostic accuracy in the earliest stages of cognitive impairment and will be further investigated in our longitudinal examination.

No abstract