A study of women diagnosed with multiple sclerosis found that treatment with 8-mg estriol (estrogen receptor agonist) reduced serum neurofilament light levels, indicating that even a weak estrogen hormone can be neuroprotective against neuronal damage.32 Overall, these findings suggest that ongoing neurodegenerative changes in female survivors may be precipitated by the absence of the protective properties of estrogen, coupled with increased risk for cardiovascular disease, leading to accelerated brain aging. This evidence concerns the gene ESR1 and multiple sclerosis.