Joint Effects of Air Pollution and Neighborhood Socioeconomic Status on Cognitive Decline - Mediation by Depression, High Cholesterol Levels, and High Blood Pressure Open Access

Mei,Yiyang (Fall 2022)

Permanent URL: https://etd.library.emory.edu/concern/etds/m613mz82x?locale=en
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Abstract

Background: Air pollution and neighborhood socioeconomic status (N-SES) are associated with adverse cardiovascular health and neuropsychiatric functioning in older adults.

Objectives: This study examines the degree to which the joint effects of air pollution and N-SES on cognitive decline are mediated by high cholesterol levels, high blood pressure (HBP), and depression.

Methods: In the Emory Healthy Aging Study, 14,390 participants aged 50+ years from Metro Atlanta, GA, were assessed for subjective cognitive decline using the cognitive function instrument (CFI). Information on the prior diagnosis of high cholesterol, HBP, and depression was collected through the Health History Questionnaire. Participants’ census tracts were matched to the 3-year average concentrations of 12 air pollutants and 16 N-SES characteristics. We used the unsupervised clustering algorithm Self-Organizing Maps (SOM) to create 6 exposure clusters based on the joint distribution of air pollution and N-SES in each census tract. Linear regression analysis was used to estimate the effects of the cluster indicator on CFI, adjusting for age, race/ethnicity, education, and neighborhood residential stability. The proportion of the association mediated by high cholesterol levels, HBP, and depression was calculated by comparing the total and direct effects.

Results: Depression mediated 19 - 87% of the association between SOM clusters and CFI. Participants living in the high N-SES and high air pollution cluster had CFI scores 0.05 (95% CI: 0.01, 0.09) points higher on average compared to those from the high N-SES and low air pollution cluster. After adjusting for depression, this association was attenuated (0.01 (95% CI: -0.04, 0.05)). HBP mediated up to 8% of the association between SOM clusters and CFI and high cholesterol up to 5%.

Conclusions: Air pollution and N-SES associated cognitive decline was partially mediated by depression. Only a small portion (<10%) of the association was mediated by HBP and high cholesterol.

Table of Contents

INTRODUCTION                                                                                                                   1 

METHODS                                                                                                                              3 

RESULTS                                                                                                                                8 

DISCUSSION                                                                                                                         11

STRENGTHS AND LIMITATION                                                                                      14

CONCLUSION                                                                                                                      15 

REFERENCES                                                                                                                       17

TABLES AND FIGURES                                                                                                      23

 

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