Depression as an effect modifier of an association between outdoor and indoor traffic noise and cognitive function - Results from the Heinz Nixdorf Recall study

Abstract

TPS 781: Health effects of noise, Exhibition Hall, Ground floor, August 27, 2019, 3:00 PM - 4:30 PM Background/Aims: Exposure to traffic noise is proposed to be associated with cognitive function. One possible contributor to impaired cognitive function is depression, which is in turn associated with high levels of noise. We studied the role of depression as a possible effect modifier of the association between outdoor and indoor traffic noise and cognitive function. Methods: Cognitive function and depressive symptoms (Centre for Epidemiologic Studies Depression Scale, CES-D) were assessed during the first follow-up examination of the German Heinz Nixdorf Recall study. Five cognitive subtests (verbal fluency, immediate and delayed recall, labyrinth test and clock-drawing test) were used for the assessment of cognitive function and further summarized to a global cognitive score (GCS). Long-term outdoor exposure to traffic noise was modeled as weighted 24-h mean (LDEN) at the baseline address of participants and corrected for indoors (LDEN_IN). We used multiple linear models adjusted for individual-level characteristics to check cross-sectional associations of traffic noise assessed outdoors and indoors with cognitive function. We investigated the effect modification role of moderate (CES-D≥17) and severe depressive symptomatology (CES-D≥21) on these associations. Results: In the study population of 2748 participants, we observed adverse associations of LDEN, LNIGHT, LDEN_IN and LNIGHT_IN with all cognitive outcomes. Associations were stronger for indoor exposures and GCS (for example, LDEN and LDEN_IN point estimates (β) were -0.18 [95% confidence interval -0.39; 0.04] and β=-0.34 [-0.49; -0.18]) per10 dB(A), respectively). The associations were stronger in participants with severe depressive symptomatology (β=-0.41 [-0.67; -0.16]) and (β=-0.55 [-1.21; -0.12]) for the association with LDEN and with LDEN_IN, respectively). Conclusions: Depressive symptoms might be an effect modifier in the association between noise and cognitive function. Indoor noise can be a more appropriate measure of exposure for studies on noise effects on health.