Adherence to a MIND-Like Dietary Pattern, Long-Term Exposure to Fine Particulate Matter Air Pollution, and MRI-Based...

Previous studies suggest that certain dietary patterns and constituents may be beneficial to brain health. Airborne exposures to fine particulate matter [particulate matter with aerodynamic diameter $$ ($$)] are neurotoxic, but the combined effects of dietary patterns and $$ have not been investigated.

We examined whether previously reported association between $$ exposure and lower white matter volume (WMV) differed between women whose usual diet during the last 3 months before baseline was more or less consistent with a Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND)-like diet, a dietary pattern that may slow neurodegenerative changes.

This study included 1,302 U.S. women who were 65-79 y old and free of dementia in the period 1996-1998 (baseline). In the period 2005-2006, structural brain magnetic resonance imaging (MRI) scans were performed to estimate normal-appearing brain volumes (excluding areas with evidence of small vessel ischemic disease). Baseline MIND diet scores were derived from a food frequency questionnaire. Three-year average $$ exposure prior to MRI was estimated using geocoded participant addresses and a spatiotemporal model.

Average total and temporal lobe WMVs were $$ [95% confidence interval (CI): 0.001, 1.48) and $$ (95% CI: 0.002, 0.37) higher, respectively, with each 0.5-point increase in the MIND score and were $$ (95% CI: $$, $$) and $$ (95% CI: $$, $$) lower, respectively, with each interquartile range (IQR) ($$) increase in $$. The inverse association between $$ per IQR and WMV was stronger ($$) among women with MIND scores below the median (for total WMV, $$; 95% CI: $$, $$), but absent in women with scores above the median ($$; 95% CI: $$, 3.72), with similar patterns for WMV in the frontal, parietal, and temporal lobes. For total cerebral and hippocampus brain volumes or WMV in the corpus callosum, the associations with $$ were not significantly different for women with high MIND scores and women with low MIND scores.

In this cohort of U.S. women, $$ exposure was associated with lower MRI-based WMV, an indication of brain aging, only among women whose usual diet was less consistent with the MIND-like dietary pattern at baseline. https://doi.org/10.1289/EHP8036.