Oestrogen and progestogen hormone replacement therapy for peri-menopausal and post-menopausal women: weight and body fat distribution

BACKGROUND: Hormone replacement therapy (HRT) is commonly prescribed to treat menopausal symptoms and to prevent post-menopausal bone loss. However, many women are concerned about hormonal replacement therapy because they believe that such treatment will result in weight gain. The effect of HRT on weight and body fat distribution has not yet been examined in systematic reviews. It is an important topic since many women decline oestrogen therapy due to their concerns about resultant weight gain, and thus forego its potential therapeutic benefits. OBJECTIVES: To evaluate the effect of unopposed oestrogen or combined oestrogen and progestogen hormone replacement therapy (HRT) upon the weight and body fat distribution of perimenopausal and postmenopausal women. SEARCH STRATEGY: The search strategy of the Menstrual Disorders and Subfertility Group was used for the identification of randomised controlled trials (RCTs). Computerised searches of MEDLINE, EMBASE, Current Contents, Biological Abstracts and CINAHL were performed. Attempts were made to identify trials from citation lists of review articles and relevant papers already obtained. In most cases, first authors of each eligible trial were contacted for additional information. All those trials that had been located as at August 1998 were examined for eligibility. SELECTION CRITERIA: All randomised, placebo or no treatment controlled trials that detailed the effect of HRT on weight or body fat distribution, including studies where HRT was combined with other therapy such as diet, supplements or exercise. Studies were eligible for consideration even though the main focus of the trial may have been on another aspect of HRT. Previous HRT use should have ceased at least one month (in the case of patches, cream or gel) or three months (for oral preparations or subcutaneous pellets) before commencement of the study. DATA COLLECTION AND ANALYSIS: Twenty two RCTs were identified that fulfilled the inclusion criteria for this review. The results of one trial were not available in a form that allowed it to be included in the meta-analysis; however, it has been included in the text of the review for discussion. Twenty four RCTs are awaiting assessment pending additional information from first authors. Two reviewers extracted the data independently, and the weighted mean differences for continuous outcomes were estimated from the data. Results for unopposed oestrogen and combined oestrogen were analysed separately, and the effect of each treatment regimen on body weight, BMI, waist-hip ratio, fat mass and skinfold measurement was examined where available. The effect of differing dosage levels on these parameters was also examined. MAIN RESULTS: Outcomes were evaluated separately for unopposed oestrogen and oestrogen/progestogen regimens. Statistical analysis was performed using the weighted mean difference for continuous outcomes as recommended by the Cochrane Menstrual Disorders and Subfertility Group. No statistically significant difference was found in mean weight gain between those using unopposed oestrogen and non-HRT users (0.66 kg, 95% CI -0.62, 1.93). No significant difference was found in mean weight gain between those using oestrogen/progestogen therapy and non-HRT users (-0.47 kg, 95% CI -1.63, 0.69). Insufficient data exist to enable meta-analysis of the effect of unopposed oestrogen on BMI. The reviewers found no statistically significant difference in mean BMI increase between those using oestrogen/progestogen and non-HRT users (-0.50, 95% CI -1.06, 0.06). Insufficient data exist to enable meta-analysis of the effect of HRT on waist-hip ratio, fat mass or skinfold thickness. REVIEWER'S CONCLUSIONS: There is evidence of no effect of unopposed oestrogen or combined oestrogen on body weight, indicating that these regimens do not cause extra weight gain in addition to that normally gained at menopause. (ABSTRACT TRUNCATED)