Abstract
[Display omitted]
•First study to identify the role of blood lipids in the relationship between air pollutant exposure and cognitive performance using MESA.•1518 adults aged 65 and above who participated in MESA Exams 1–6 (2000–2018).•TC and LDL-C were not mediators in the air pollutant-cognition relationship.•TC and LDL-C were not clinically meaningful modifiers in the air pollutant-cognition relationship.
Evidence on blood lipids in the air pollutant-cognition relationship is scarce. In this study, we identified the role of blood lipids in the air pollutant-cognition relationship in the Multi-Ethnic Study of Atherosclerosis (MESA) cohort.
The study sample consisted of 1,518 adults who participated in MESA Exams 1–6 (2000–2018). Outcome were three composite scores of the Cognitive Abilities Screening Instrument (CASI) test, the Digit Symbol Coding test (DSC), and the Digit Span (DS) test at Exam 6. Outdoor residential concentrations of PM2.5, NO2, and NOx between Exams 1 and 5 were assessed using validated spatiotemporal models. Total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) concentrations in blood at Exam 5 were evaluated as mediators or modifiers using linear regression models. Models assessed gender and race/ethnicity related heterogeneity in air pollutant-cognition and blood lipid-cognition associations.
The direct effect of NO2 and NOx on DSC scores was significant (ß = −2.64 95 % CI −4.87 to −0.40 for NO2; ß = −3.01 95 % CI −5.20 to −0.83 for NOx, per interquartile range increase), but there was no evidence of mediation by cholesterol levels. The association of CASI scores with NO2 and NOx was modified by LDL-C (β = 0.03 for NO2, p = 0.01; β = 0.02, p = 0.03 for NOx). Associations of cognitive performance with air pollutant exposure and blood lipids did not vary by gender or racial identity.
TC and LDL-C were not mediators or clinically meaningful modifiers in the air pollutant-cognition relationship.