Background: This is the first study to evaluate blood-based neuropathological biomarkers in the World Trade Center (WTC)- affected community members. More than 20 years after 9/11, the ageing WTC cohort is at risk of accelerated cognitive decline. This study compares neuropathological biomarkers of enrollees at the WTC Environmental Health Center (WTC-EHC) with documented exposure data, including the WTC dust cloud on 9/11/2001, with our cohort at the New York University Alzheimer's Disease Research Center (NYU-ADRC) without exposure to the WTC dust/fumes.
Methods: Plasma Aβ42, Aβ40, NfL, and GFAP were assessed in 101 enrollees in the WTC-EHC and 296 enrollees of NYU-ADRC. In linear regression models, the plasma biomarkers were regressed on WTC dust cloud exposure (yes or no). A subsample of 72 WTC participants aged 60 to 83 was compared to similar-aged enrollees of NYU-ADRC, including 247 cognitively unimpaired (CU) (n=80) less than 70 years old, and n=167 aged 70 years or older, and n= 49 subjects with MCI, studied with age, sex, and race/ethnicity (non-Hispanic white vs. all others) as covariates.
Results:: In a linear regression model adjusted for age, sex, and race/ethnicity, compared to WTC-EHC participants who were not exposed to the WTC dust cloud on 9/11, there were significantly lower plasma Aβ42 levels among WTC-EHC participants who were exposed to the WTC dust cloud (β=-1.23, 95%CI[-2.12,-0.35], p=0.007), cognitively unimpaired (CU) participants of NYU-ADRC age 70 and older (β=-1.53, 95%CI[-2.30,-0.75], p<0.001), and MCI in NYU-ADRC (β=-1.61, 95%CI[-2.48,-0.74], p<0.001), but did not reach significance for CU participants of NYU-ADRC less than age 70 (β=-0.60, 95%CI[-1.42,0.21], p=0.146). Within WTC-EHC, exposure to the WTC dust cloud on 9/11 was associated with lower plasma Aβ42 levels (β=-1.06, 95%CI[-2.11,-0.01], p=0.05) but did not reach significance for plasma Aβ40, NfL, or GFAP. Other phospho-tau are under investigation.
Conclusion: Significantly lowered plasma Aβ42 levels were observed among WTC-EHC participants with WTC dust cloud exposure, NYU-ADRC MCI participants, and older CU participants compared to WTC-EHC participants without WTC dust cloud exposure. Lowered plasma Aβ42 levels were possibly associated with a higher risk of cognitive decline in the WTC-exposed community, which warrants further investigation.