Almost every headline number about hormone therapy, in both directions, is a relative risk, and relative risks can make small absolute changes sound dramatic.

In the WHI trial, the widely quoted increases translated to roughly 7 to 8 additional events per 10,000 women per year for each outcome, a small number in absolute terms. The same is true in the other direction: older observational studies suggesting 40 to 50 percent lower heart disease risk with hormone use were also relative-risk framing of an effect that turned out to be smaller and more uncertain once tested in a randomized trial. A responsible answer about any hormone therapy risk or benefit should give both the relative and the absolute number.

What to know about this answer

This isn't a contested scientific question so much as a communication failure that runs through the entire field - both pro- and anti-hormone-therapy arguments routinely lean on relative-risk framing because it sounds more dramatic in either direction.

What the research shows, and which source each finding rests on

WHI absolute excesses on estrogen plus progestogen: 7 more coronary events, 8 more strokes, 8 more pulmonary embolisms, and 8 more breast cancers per 10,000 person-years, against 6 fewer colorectal cancers and 5 fewer hip fractures.

B[1]

The Nurses' Health Study observational cohort found major coronary disease relative risk 0.56 (44% lower) in current hormone users - a relative-risk figure from the healthy-user-biased cohorts that the WHI was designed to test and did not confirm as delivered.

D[2]

The WHI 'global index' cuts both ways: in the estrogen-plus-progestogen fracture paper, even women at highest fracture risk showed no net benefit on the global index, while in the estrogen-alone arm the same index favored therapy in women 50-59 (19 fewer events per 10,000 per year); quoting one arm's index without the other is a form of cherry-picking.

B[1]B[3]

Where the real disagreement is

Each position is shown with its own sources. A position listed here is not necessarily the accepted view.

Both sides misuse relative risk, and the fix is the same either way

clinicians such as Dr. Sharon Malone, who explicitly translate WHI numbers into absolute terms

Whether the claim is that hormone therapy raises breast cancer risk 26 percent or halves heart disease risk, both are relative-risk statements. Translating the WHI breast-cancer number into 'less than one woman per thousand per year' is the kind of absolute-risk translation that should accompany every such claim.

B[1]

What would settle it: Not a research question - this is a standard of communication. The fix is that every risk or benefit claim about hormone therapy should be paired with its absolute number and denominator.

What is really going on here

  1. Am I being quoted a relative risk or an absolute risk - how many women per 1,000 per year does that actually mean?
  2. Am I only hearing about the arm of the WHI trial that supports one side of the argument?

Questions for your doctor

  1. Can you translate that risk percentage into an absolute number, like events per 1,000 women per year?
  2. Is the number you're quoting from a randomized trial or an observational study?
  3. Does that number apply to the estrogen-only regimen, the combined regimen, or both?

Questions with no answer yet

Would a standardized requirement to report both relative and absolute risk together in patient materials and public messaging measurably change how women understand and decide about hormone therapy?

Not directly studied yet

No research does not mean it does not work, and it does not mean it works. It means nobody has tested it yet.

What is known: Several clinicians in this field independently teach this dual framing as a correction to public confusion, but this is described as a matter of communication practice, not a tested intervention. No study has measured whether requiring both numbers together changes comprehension or decisions in this specific context.

What would test it: A patient-comprehension or decision-quality study comparing relative-only, absolute-only, and combined risk framings specifically for hormone therapy counseling.

Does selectively quoting only one arm of the trial's combined risk index, without the other arm that points the opposite direction, meaningfully change what patients or clinicians conclude, compared with seeing both together?

Not directly studied yet

No research does not mean it does not work, and it does not mean it works. It means nobody has tested it yet.

What is known: The trial's own combined-outcome index favored therapy in younger women in one treatment arm while showing no net benefit even in high-fracture-risk women in the other arm, and both patterns come from the same broader trial program. Whether presenting only one arm's index changes conclusions compared with presenting both has not been tested as its own question.

What would test it: A framing-effect study presenting one arm's data alone versus both arms together to see whether conclusions or perceived risk differ.

Sources

  1. 1.Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women's Health Initiative randomized controlled trial.Rossouw JE, et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the WHI randomized controlled trial. JAMA. 2002;288(3):321-33. · Randomised trial
  2. 2.Postmenopausal estrogen therapy and cardiovascular disease. Ten-year follow-up from the nurses' health study.Stampfer MJ, et al. Postmenopausal estrogen therapy and cardiovascular disease: ten-year follow-up from the Nurses' Health Study. N Engl J Med. 1991;325(11):756-62. · Comparative or small study
  3. 3.Effects of estrogen plus progestin on risk of fracture and bone mineral density: the Women's Health Initiative randomized trial.Cauley JA, et al. Effects of estrogen plus progestin on risk of fracture and bone mineral density (WHI). JAMA. 2003;290(13):1729-38. · Randomised trial

The letter grades the type of study behind a claim, not the answer itself.

This page is general information based on published research and public sources. It is not medical advice and not a personal assessment, and it does not replace a conversation with your doctor. Peritale is a wellness product, not a medical device, and is not intended to diagnose, treat, cure or prevent any disease. For any medical question, speak with a licensed clinician.

You are not imagining it

In about seven minutes on your phone, Peritale reads five signal systems and maps your symptoms, so you can see that what you feel is real, follow your hormonal transition over time, and walk into your doctor ready to ask for the care you deserve. Your first check is free, no credit card.

Start Free Mapping

Related questions