Women who start hormone replacement therapy (HRT) within a year after menopause may have a lower risk of developing osteoporosis, according to research presented at the American Academy of Orthopaedic Surgeons 2026 (AAOS) annual meeting in New Orleans.

Researchers at Stony Brook University, New York, used the health records database TriNetX to analyze data from more than 137,000 postmenopausal women younger than 60 years. They compared women who started HRT within a year of a menopause diagnosis to matched peers who did not receive HRT.

“The early HRT group was defined as those women receiving HRT within the first year of diagnosis of menopause,” said study author James Barsi, MD, an orthopedic surgeon at Stony Brook Children’s Hospital in Stony Brook, New York.

At 3 years, researchers found no statistically significant difference in osteoporosis diagnoses between the early HRT and no-HRT groups (1.11% vs 1.15%; risk ratio [RR] 1.03; 95% CI, 0.95-1.13; P = .449).

Within 5 years, however, women who did not receive HRT had a significantly higher rate of osteoporosis (2.08% vs 1.91%; RR, 1.09; 95% CI, 1.02-1.16; P = .010). At the final follow-up at 5 years, the gap widened further: 5.31% of women in the no-HRT group were diagnosed with osteoporosis compared with 4.39% in the early HRT group (RR 1.21; 95% CI, 1.16-1.26; P < .001).

Fracture outcomes followed a similar pattern. At 3 years, fracture rates did not significantly differ (1.94% vs 2.03%; RR, 1.05; 95% CI, 0.98-1.12; P = .171). By 5 years, fractures were modestly but significantly more common in women who did not receive HRT (3.55% vs 3.37%; RR, 1.05; 95% CI, 1.00-1.11; P = .034). Cumulative fracture rates were 7.06% in the no-HRT group compared with 6.21% in the early HRT group (RR, 1.14; 95% CI, 1.10-1.18; P < .001).

While short-term fracture risk did not differ, the longer-term findings suggest cumulative skeletal benefits, Barsi said.

“While we did not find a significant difference in fractures in the short term of 3 years, we did find differences in the medium to longer term,” said Barsi. “This would suggest that the effects of HRT seem to be more cumulative in nature and are protective in the long term.”

The study did not differentiate between estrogen-only vs combined estrogen-progestin therapy or whether the women took the therapies orally or transdermally.

“Unfortunately, the database did not get into the details of the type or route of hormone therapy received,” Barsi said.

According to Abigail Campbell, MD, a sports medicine orthopedist and co-director of the Women’s Sports Medicine Center at NYU Langone Health, New York City, the biological mechanism behind the findings is plausible, but she urged caution in interpretation.

“The reason that women after age 50 get osteoporosis is because their estrogen level drops, which is protective against bone loss,” said Campbell, who was not involved in the study. “Hormone replacement gives back some of the estrogen; therefore bone loss slows down.” 

Campbell said the delayed separation in outcomes — with differences emerging at 5 years but not at 3 years — is consistent with how menopause unfolds.

She warned that increased public attention on hormone therapy may lead some patients to seek treatment inappropriately.

“Yes, it can do amazing things for the right person, but the problem with HRT is it’s not recommended or safe for everyone,” she said.

Some women — including those with a history of hormone-sensitive cancers — should not take hormone therapy, and said decisions should involve gynecologists or menopause specialists, Campbell added.

For now, Campbell said clinicians should continue recommending proven strategies for bone health.

“Weight-bearing exercise and resistance exercise have all been shown unequivocally to be important for bone health,” she said. “These are all things that we know that are tried and true.”

Barsi and Campbell reported having no relevant disclosures.

Lara Salahi is a health journalist based in Boston.