August 28, 2019
Hormone therapy (HT) neither contributes to nor prevents changes in muscle strength in postmenopausal women, a systematic review and meta-analysis has found.
"The small potential benefit for maintaining muscle mass in the general population of postmenopausal women likely does not outweigh the potential risks of prolonged HT," the researchers write.
Some studies suggest hormone therapy may protect against age-related decline in muscle mass and strength, or sarcopenia, in menopausal and postmenopausal women, on the basis of the hypothesis that declining estrogen levels during the menopause transition accelerate the assault on lean body mass.
Ayesha A. Javed, MS, of the McMaster Institute for Research on Aging at McMaster University in Hamilton, Canada, and colleagues, conducted a systematic review and meta-analysis of randomized clinical trials comparing postmenopausal women undergoing hormone therapy (estrogen only or a combination of estrogen and progesterone) and women not receiving HT. The findings, reported online today in JAMA Network Open, are highly variable but overall indicate no statistically significant difference in lean body mass (LBM) changes between treatment and control groups.
In total, the analysis included 12 studies comprising 4474 participants (mean age 59 years). The median duration of follow-up was 2 years. Treatment varied by duration (ranging from 9 to 25 days per month to more than 8 years), formulation (15 of the 22 treatment groups used estrogen–progesterone combination therapy and 7 used estrogen only), and dosage.
The primary outcome of interest was change in LBM. Subgroup analyses looked at between-group differences on the basis of hormone therapy type and dosage, duration of follow-up, time since menopause, study quality, and type of LBM measurement.
The main effect analysis showed that, across all studies, hormone therapy was associated with a nonstatistically significant loss of 0.06 kg less LBM (95% confidence interval [CI], -0.05 to 0.18) compared with the control group.
Similarly, the between-group differences observed in the subgroup analyses did not achieve statistical significance. Specifically, the between group comparisons showed the following differences in LBM changes:
- Stratified by therapy type and dosage, HT users lost 0.06 kg more to 0.19 kg less LBM than nonusers.
- Stratified by duration of follow-up, HT users lost 0.0 to 0.10 kg less LBM than nonusers.
- Stratified by time since menopause, HT users lost 0.01 to 0.13 kg less LBM than nonusers.
- Stratified by study quality, HT users lost 0.04 to 0.20 kg less LBM than nonusers.
- Stratified by type of LBM measurement, HT users lost 0.06 to 0.07 kg less LBM than nonusers.
The nonsignificant reduction in lost LBM observed in the treatment group "is unlikely to be clinically relevant for the average postmenopausal woman," the authors write.
Women older than 50 years are reported to lose approximately 1% of muscle mass each year, the researchers say. "At this rate, it would take approximately 66 years for a woman of average height and LBM to become sarcopenic according to the cutoff of 7.4 kg/m2 recommended by the European Working Group on Sarcopenia."
Additionally, with respect to the slight increase in sarcopenia-free time associated with treatment, "most women would not live long enough to experience these additional sarcopenia-free years," the authors stress.
Although it is possible that hormone therapy could be beneficial to women with lower muscle mass at baseline, "to our knowledge, no research in this specific population has been conducted," the authors write.
The study findings are limited by the high risk for bias in many of the studies, the authors write. Despite these limitations, however, "the results of this review remained consistent across subgroups, indicating that the overall body of literature has not shown a meaningful association between HT and muscle mass," they note.
Given the importance of muscle retention in aging women, interventions other than hormone therapy should be investigated, the authors explain. "Further work is also required to determine whether HT is beneficial to muscle strength or function," they state, noting that muscle strength plays a bigger role in health outcomes than muscle mass.
Study author Parminda Raina holds a Tier 1 Canada Research Chair in Geroscience and the Raymond and Margaret Labarge Chair in Research and Knowledge Application for Optimal Aging. The remaining authors have disclosed no relevant financial relationships.