Prolonged endogenous oestrogen use linked to increased levels of AD biomarkers

Longer exposure to endogenous oestrogen appears to contribute to an increase in the levels of biomarkers for Alzheimer’ disease (AD) in its preclinical phase, a study has found.

The study included 75 women from Gothenburg, Sweden, who had undergone natural menopause and were free of dementia. The researchers collected data on reproductive period (age at menarche to age at menopause) from interviews conducted in 1968–1980 and performed lumbar puncture to obtain cerebrospinal fluid (CSF) samples in 1992–1994. They measured Aβ42, Aβ40, P-tau, and T-tau levels in CSF samples using immunochemical methods.

Linear regression models showed that women with longer vs shorter reproductive period had lower levels of Aβ42 (β −19.2, p=0.01), higher levels of P-tau (β 0.03, p=0.01), and lower ratio of Aβ42/Aβ40 (β −0.02, p=0.01). On the other hand, there was no difference observed in T-tau levels (β 0.01, p=0.46).

In separate analyses investigating the different components of reproductive period, earlier age at menarche correlated with higher levels of P-tau (β −0.07, p=0.031) and lower Aβ42/Aβ40 ratio (β 0.05, p=0.021). Meanwhile, there was no association seen for Aβ42 (β 31.1, p=0.11) and T-tau (β −0.001, p=0.98).

Finally, CSF biomarkers for AD did not differ according to age at menopause.

The findings should be confirmed in larger populations, according to the researchers.