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In the early 1990s the Canadian Task Force on Preventive Health Care issued a grade B recommendation for counselling perimenopausal women regarding the use of estrogen replacement therapy (ERT) for the primary prevention of osteoporotic fractures.1 At that time, the large observational studies that constituted the best available evidence further indicated the potential for ERT to confer a cardioprotective benefit to women2,3,4 and to prevent bone loss.1,5 The early large observational studies indicated a small but significant risk of breast cancer,6,7,8 and of endometrial cancer among women with an intact uterus taking unopposed estrogen therapy.9
The evidence base has grown in the last decade, as numerous clinical trials have been conducted on the potential positive and negative effects of hormone replacement therapy (HRT) for various chronic conditions. This statement is based on 3 systematic reviews conducted by the task force6,10,11 and by others12 of the potential benefits and harms of HRT, and it incorporates the results of the estrogen-plus-progestin and the estrogen-only trials of the Women's Health Initiative (WHI), stopped early in May 2002 and February 2004 respectively because of safety concerns.13,14 This statement does not review the evidence for use of HRT in the treatment of menopausal symptoms; instead, it provides a brief discussion of considerations that may be useful for clinicians and their patients when deciding whether HRT should be taken for symptom relief as well as a balance sheet of risks and benefits (Table 1).
The US Preventive Services Task Force,15 the American College of Obstetricians and Gynecologists,16 the North American Menopause Society (NAMS),17 Health Canada,18 the US Food and Drug Administration (FDA)19 and, in a joint statement, the Heart and Stroke Foundation of Canada, the Society of Obstetricians and Gynaecologists of Canada and the Canadian Cardiovascular Society20 all have recommended that asymptomatic women should not use combination estrogen– progestin therapy for the prevention of cardiovascular disease or other chronic diseases, because the risks outweigh the benefits. They advocate that women considering HRT should discuss their individual risks with their physician. These groups also recommend that women who choose to take HRT to relieve menopausal symptoms should use as low a dose as possible and for as short a time as possible, with periodic re-evaluation of whether HRT is still required. The FDA and NAMS have extended these recommendations to include all estrogen preparations, including unopposed estrogen. Their stance is that, until there is evidence from randomized controlled trials showing benefit, other methods of lowering cardiovascular disease and cancer risk (e.g., smoking cessation, and lifestyle and diet changes) should be used.
The references and the list of task force members are available online at www.cmaj.ca/cgi/content/full/170/10/1535.
Contributors: Nadine Wathen drafted the current article and made subsequent revisions. Denice Feig, Beth Abramson and Angela Cheung authored the original systematic evidence reviews, critically reviewed the current article and reviewed subsequent revisions. John Feightner critically reviewed the current article and reviewed subsequent revisions. The Canadian Task Force on Preventive Health Care critically reviewed the evidence and developed the recommendations according to its methodology and consensus development process.
The Canadian Task Force on Preventive Health Care is an independent panel funded through a partnership of the federal and provincial/territorial governments of Canada.
Competing interests: Nadine Wathen has received research funding from Wyeth Canada. Angela Cheung has received honoraria to participate in CME events partially or fully supported by Eli Lilly, Merck, Proctor & Gamble, Aventis and Novartis. These companies have also contributed unrestricted educational grants in support of Toronto City-wide Osteoporosis Rounds, which Angela Cheung chairs. No competing interests declared for Beth Abramson or the members of the Canadian Task Force on Preventive Health Care.
Correspondence to: Canadian Task Force on Preventive Health Care, 117–100 Collip Circle, London ON N6G 4X8; fax 519 858-5181; ctf/at/ctfphc.org