Would expect to see research focused on compounds that increase Reelin expression too, in addition to direct supplementation. A mouse study a couple years later showing nicotine increasing Reelin expression: https://pubmed.ncbi.nlm.nih.gov/23385624/
Not a Doctor but if I had a loved one at-risk or experiencing age-related cognitive impairment, it's probably worth trying rather than waiting for scientific consensus which may take years and will probably be blocked by the FDA so some pharma company can develop patented neuro-nicotine or whatever.
I loved nicotine, but it terribly exacerbates my rheumatoid arthritis in my hands, inflames blood vessels in my lower arms (to the point of waking with my arms completely numb in the middle of the night) and gives me terrible heart palpitations that woke me up (if I consumed nicotine a few hours before bed).
https://www.sciencedirect.com/science/article/abs/pii/S00062...