Postmenopausal hormone therapy and body composition--a substudy of the estrogen plus progestin trial of the Women's Health Initiative.
BACKGROUND
It has been suggested that hormone therapy may help counter undesirable changes in body composition in older women.


OBJECTIVE
This study was designed to test whether estrogen plus progestin (E+P) therapy favorably affects age-related changes in body composition in postmenopausal women.


METHODS
The substudy was composed of 835 women from the estrogen plus progestin trial of the Women's Health Initiative who were randomly assigned to receive either E+P therapy (n = 437) or placebo (n = 398). The women had a mean age of 63.1 y and, on average, were 13.8 y past menopause. More than 17% of the participants were from an ethnic minority. No significant differences in baseline body composition (measured with dual-energy X-ray absorptiometry) by intervention assignment were observed.


RESULTS
After 3 y of intervention, the women who received active E+P therapy lost less lean soft tissue mass (-0.04 kg) than did the women who received placebo (-0.44 kg; P = 0.001). Additionally, the women in the E+P group had less upper-body fat distribution than did the women in the placebo group (change in ratio of trunk to leg fat mass: -0.025 for the E+P group and 0.004 for the placebo group; P = 0.003). A sensitivity analysis, which was conducted on the women who took > or = 80% of the study medication during the intervention period, corroborated the findings from the intent-to-treat analysis.


CONCLUSIONS
A 3-y E+P intervention significantly reduced both the loss of lean soft tissue mass and the ratio of trunk to leg fat mass in postmenopausal women. However, the effect sizes were small, and whether these changes in body composition lead to significant health benefits remains to be confirmed.
Chen
Zhao
Z
Division of Epidemiology and Biostatistics, Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ 85724, USA. zchen@u.arizona.edu
Bassford
Tamsen
T
Green
Sylvan B
SB
Cauley
Jane A
JA
Jackson
Rebecca D
RD
LaCroix
Andrea Z
AZ
Leboff
Meryl
M
Stefanick
Marcia L
ML
Margolis
Karen L
KL
D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000368:Aged; D001823:Body Composition / Q000187:drug effects* / Q000502:physiology; D004311:Double-Blind Method; D015914:Estrogen Replacement Therapy; D004966:Estrogens, Conjugated (USP) / Q000494:pharmacology*; D005260:Female; D006801:Humans; D017258:Medroxyprogesterone Acetate / Q000494:pharmacology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D017698:Postmenopause / Q000187:drug effects / Q000502:physiology; D012680:Sensitivity and Specificity
D004966:Estrogens, Conjugated (USP); D017258:Medroxyprogesterone Acetate