Postmenopausal hormone replacement therapy modifies skeletal muscle composition and function: a study with monozygotic twin pairs.
We investigated whether long-term hormone replacement therapy (HRT) is associated with mobility and lower limb muscle performance and composition in postmenopausal women. Fifteen 54- to 62-yr-old monozygotic female twin pairs discordant for HRT were recruited from the Finnish Twin Cohort. Habitual (HWS) and maximal (MWS) walking speeds over 10 m, thigh muscle composition, lower body muscle power assessed as vertical jumping height, and maximal isometric hand grip and knee extension strengths were measured. Intrapair differences (IPD%) with 95% confidence intervals (CI) were calculated. The mean duration of HRT use was 6.9 +/- 4.1 yr. MWS was on average 7% (0.9 to 13.1%, P = 0.019) and muscle power 16% (-0.8 to 32.8%, P = 0.023) greater in HRT users than in their cotwins. Thigh muscle cross-sectional area tended to be larger (IPD% = 6%, 95% CI: -0.07 to 12.1%, P = 0.065), relative muscle area greater (IPD% = 8%, CI: 0.8 to 15.0%, P = 0.047), and relative fat area smaller (IPD% = -5%, CI: -11.3 to 1.2%, P = 0.047) in HRT users than in their sisters. There were no significant differences in maximal isometric strengths or HWS between users and nonusers. Subgroup analyses revealed that estrogen-containing therapies (11 pairs) significantly decreased total body and thigh fat content, whereas tibolone (4 pairs) tended to increase muscle cross-sectional area. This study showed that long-term HRT was associated with better mobility, greater muscle power, and favorable body and muscle composition among 54- to 62-yr-old women. The results indicate that HRT is a potential agent in preventing muscle weakness and mobility limitation in older women.
Ronkainen
Paula H A
PH
Dept. of Health Sciences and Finnish Centre for Interdisciplinary Gerontology, Univ. of Jyväskylä, PO Box 35 (Viv), FIN-40014 Jyväskylä, Finland. paula.h.a.ronkainen@jyu.fi
Kovanen
Vuokko
V
Alén
Markku
M
Pöllänen
Eija
E
Palonen
Eeva-Maija
EM
Ankarberg-Lindgren
Carina
C
Hämäläinen
Esa
E
Turpeinen
Ursula
U
Kujala
Urho M
UM
Puolakka
Jukka
J
Kaprio
Jaakko
J
Sipilä
Sarianna
S
D015914:Estrogen Replacement Therapy; D004967:Estrogens / Q000097:blood / Q000494:pharmacology*; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008593:Menopause / Q000502:physiology*; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000502:physiology; D014057:Tomography, X-Ray Computed; D018433:Twin Studies as Topic; D014430:Twins, Monozygotic; D016138:Walking / Q000502:physiology
D004967:Estrogens