A study evaluating the impact of menopause during the course of multiple sclerosis (MS), including disease activity and disability progression, has found that after menopause there is a reduced relapse rate, but that disability progression continues at a similar rate, compared to the premenopausal period.
The retrospective, longitudinal cohort study in the journal European Neurology also concluded that these findings persisted in the subgroup of patients without changes in disease-modifying treatment (DMT) or a diagnosis of at least one vascular comorbidity (including smoking, hypertension, diabetes or dyslipidemia) during the observation period.
“Hormonal variations are known to influence the course of MS,” wrote the Portuguese authors.
The study enrolled 37 women, all older than 44, who were postmenopausal (mean age at the time of menopause of 49.8 years), and had a diagnosis of MS at least 1 year before menopause.
The investigators assessed the impact of menopause during the course of MS by comparing clinical and radiologic outcomes within 5 years before and after menopause.
The analysis was repeated in the subgroup of patients without changes in DMT or in comorbidities detected during the observation period because these factors could also influence MS outcomes.
Patients were evaluated every 3 to 6 months, along with requested magnetic resonance imaging by the assistant physician.
Slightly more than half the study patients (54.1%) switched to DMT during the observation period; however, only 18.9% of patients changed to DMTs after menopause.
Median duration of the premenopausal and postmenopausal periods was 5.0 years.
Within 5 years following menopause, there was a decrease in the annualized relapse rate: 0.37 premenopause vs. 0.08 postmenopause (P ≤ 0.001), compared with the same period before menopause.
However, the progression rate of the Expanded Disability Status Scale (EDSS) remained stable: 0.13 EDSS point/year for both premenopause and postmenopause (P = 0.935).
Similarly, EDSS progression events frequency was similar before and after menopause: 37.8% vs. 48.6%, respectively (P = 0.424).
In the subgroup of patients with a disease duration ≤ 14 years, there was a decrease in annualized relapse rate after menopause: 0.46 premenopause vs. 0.15 postmenopause (P = 0.001).
On the other hand, EDSS progression was similar for the subgroup: 1.74 premenopause vs. 2.82 postmenopause (P = 0.243).
Frequency of EDSS progression events also did not change significantly: 36.8% premenopause vs. 42.1% postmenopause.
In patients with disease duration longer than 14 years, there was also a decrease in the annualized relapse rate after menopause: 0.27 premenopause vs. 0.01 postmenopause (P = 0.002).
But neither EDSS progression nor frequency of EDSS progression events changed meaningfully in this group of patients.
“Our results are consistent with the proposed mechanisms of action of estrogen and the effect of its reduction,” the authors wrote. “The estrogen decay might account for the reduction of inflammation, which might relate to the reduction in disease activity observed after menopause, but also for the loss of the neuroprotective properties of estrogen, which might contribute to the persistent disability progression following menopause.”
Because all women in the study were at least in their mid-40s, the authors were unable to separate the effect of aging and suppression of ovarian function.