Abstract Body
Background: Research on air pollution and cognitive function is limited particularly among older women. A genetic risk factor for cognitive decline is the allele apolipoprotein ε4 (APOE ε4) but little is known about its potential interaction with air pollution. We investigated associations between long-term exposure to ambient air pollution and cognitive status in older women. We assessed effect modification by APOE ε4 status.Methods: In a follow-up examination of the SALIA cohort in 2012-13, 542 women aged ≥65 years living in Germany were clinically examined. Cognitive function was assessed using the CERAD-Plus neuropsychological test battery. APOE ε4 polymorphisms were assessed using buccal swabs or blood samples. Covariate information was obtained by interview. Long-term concentrations of particulate matter <2.5µm in diameter (PM2.5), nitrogen dioxide, black carbon and ozone modelled by fine spatial scale (100m x 100m) hybrid land-use regression were assigned to residential addresses. Cross-sectional associations were assessed using logistic regression models adjusted for age, body mass index, APOE ε4 status, depression, educational level, and smoking. Effect modification by APOE ε4 status was tested with interaction analysis and stratification. Results: Annual ozone concentrations were associated with an increased risk of lower performance of psycho-motoric domains assessed by the trail-making test (OR=1.62, 95%CI 1.04-2.59). No associations were found with other cognitive domains. APOE ε4 status modified the effect of: annual ozone in those without APOE ε4 allele with lower semantic memory (OR=2.01, 1.36-3.03) compared to those with APOE ε4 (OR=1.10, 0.62, 2.01); annual PM2.5 in those with APOE4 ε4 with lower visuospatial function (OR=1.90, 1.06-3.48) and psycho-motoric function (OR=1.93,1.05-3.64) compared with those without APOE4 ε4 (OR=0.79, 0.56, 1.12) and (OR= 0.94, 0.68, 1.30) respectively. Conclusion: Ozone and PM2.5 exposures may be a risk factor for lower cognitive function among older women, but the risk may vary depending on APOE ε4 status.
