Plant-food rich diet may not cut dementia risk, even when started later in life, study finds
May also means may not....
https://doi.org/10.1212/WNL.0000000000214916
Abstract
This prospective longitudinal analysis of the Multiethnic Cohort Study, based in Hawaii and California (primarily Los Angeles County), included data on African American, Japanese American, Latino, Native Hawaiian, and White participants who completed food frequency questionnaires at baseline (1993–1996; age 45–75 years) and at 10-year follow-up (2003–2008) and whose Medicare claims were linked to identify incident ADRDs. A priori indices for the overall plant-based diet index (PDI), the healthful plant-based diet index (hPDI), and the unhealthful plant-based diet index (uPDI) were analyzed in Cox regression models for ADRD.
The analysis included 92,849 participants (mean age 59.2 years, 55.1% female, 21,478 with ADRDs) for the baseline diet and 45,065 participants (8,360 with ADRDs) for the 10-year dietary change. For the baseline diet, comparing the highest vs lowest quintile, PDI and hPDI were associated with 12% (hazard ratio [HR] 0.88; 95% CI 0.85–0.92) and 7% (HR 0.93; 95% CI 0.89–0.97) lower risks of ADRD, respectively, whereas uPDI was related to a 6% higher risk (HR 1.06; 95% CI 1.01–1.10). For the dietary change over time, the strongest association with ADRD was observed for uPDI rather than for PDI or hPDI. Compared with those with a stable score (<0.5 SD change), participants with a large increase in uPDI (≥1 SD) showed a 25% higher risk (HR 1.25; 95% CI 1.15–1.36) and those with a large decrease in uPDI showed an 11% lower risk (HR 0.89; 95% CI 0.84–0.94). The associations between the plant-based diet indices and ADRD were generally similar by age group (<60 vs ≥60 years at baseline), race and ethnicity, or APOE ℇ4 carrier status.
Observational epidemiology with clinically insignificant hazard ratios of 1.25 is useful to generate a hypothesis, but nothing else. So yeah, "maybe", they don't know.