Hrt for a women starting at 70

Starting hormone replacement therapy at age 70 carries more risk than benefit for most women, and the evidence for starting that late is thin.

The best trial evidence comes from the Women's Health Initiative (WHI) and the WISDOM trial. WISDOM randomized women with an average age of 63 (close to 70) to combined estrogen-progestin or placebo. It found a large increase in venous thromboembolism (VTE) — hazard ratio 7.36 — and a significant increase in cardiovascular events [4]. The WHI showed similar patterns: women starting HRT after age 60 had higher absolute risks of stroke, VTE, and breast cancer, with no coronary benefit [7, 8]. The "timing hypothesis" — that HRT helps if started near menopause but harms if started later — is the dominant explanation. Starting at 70 is the worst-case scenario for that hypothesis.

The evidence for benefit at this age is weak. Fracture prevention is real: the WISDOM trial showed a 31% reduction in osteoporotic fractures (hazard ratio 0.69), but this did not reach statistical significance [4]. A 2019 review confirms HRT reduces fractures but says the breast cancer risk precludes recommending it for population-level fracture prevention [3]. For symptom relief, the question is different — if a 70-year-old has severe hot flashes or vaginal atrophy that disrupts life, low-dose vaginal estrogen is an option with minimal systemic absorption and no significant breast cancer signal in the Finnish cohort [2]. But systemic HRT for symptoms at 70 is unusual; most women's vasomotor symptoms have resolved by that age.

The breast cancer risk is dose- and duration-dependent. The Finnish nationwide cohort of over 110,000 women found that oral or transdermal estradiol for 5 years or more increased breast cancer risk by 44% (SIR 1.44) [2]. The same study found that vaginal estrogen showed no significant increase. A meta-analysis of observational studies paradoxically found that HRT use before or after breast cancer diagnosis was associated with better survival (HR 0.88 for prediagnosis use, 0.34 for postdiagnosis use) [1], but this is likely healthy-user bias — women healthy enough to be prescribed HRT after cancer are a selected group, not evidence that HRT is protective.

The route matters. Transdermal estrogen avoids first-pass liver metabolism and has lower VTE and stroke risk than oral estrogen in observational studies [6]. The ESTHER study found oral estrogen increased VTE risk while transdermal did not [5]. For a 70-year-old, if HRT is considered at all, transdermal is the safer route. But even transdermal carries the breast cancer signal from the Finnish data [2].

The evidence does not include a single randomized trial designed for women starting HRT at age 70. Every major trial enrolled women with an average age in the early 60s. The harms are extrapolated downward, not measured directly. That is a gap, not a safety signal.

My call: for a 70-year-old woman without severe symptoms that have failed other treatments, starting systemic HRT is not supported by the evidence. The risks of VTE, stroke, and breast cancer are real and increase with age at initiation. Vaginal estrogen for isolated genitourinary symptoms is a different question and appears safer. Confidence: moderate.