Osteoporosis affects a third of women after menopause

Bone fragility after menopause is a major driver of fractures and the loss of independence that can follow, and prevention works best when high-risk women are identified early. The researchers wanted two things: a reliable figure for how common osteoporosis is among postmenopausal women, and a clear picture of which factors genuinely mark out those at highest risk. Individual studies have pointed at many candidate risk factors over the years, but each on its own is too small and too local to settle which associations hold up. Pooling them offers a sturdier basis for deciding who deserves early attention.

The team searched four English-language databases and four Chinese databases for studies published up to May 2026 that had followed postmenopausal women and used multivariate statistical models to pick apart which factors independently predicted osteoporosis. Thirty-seven studies covering 32,366 women met the criteria, and 36 of them reported prevalence figures. Following the PRISMA guidelines, the reviewers extracted the data and pooled the odds for each candidate risk factor. Because the included studies varied considerably, they used statistical models designed for disagreeing studies and ran sensitivity checks on the main findings.

Across the included studies, 33.87% of postmenopausal women had osteoporosis. The strongest risk signals were being more than 10 years past menopause, associated with 2.81 times the odds, and having two or more births, at 3.07 times the odds. Smoking, lack of exercise, a previous fracture and diabetes were each linked with meaningfully higher odds as well. On the protective side, a higher body mass index, an older age at menopause and oestrogen replacement therapy were all associated with lower odds, with oestrogen therapy showing the strongest protective association at 0.45 times the odds. Notably, family history of osteoporosis, regular exercise, hypertension and calcium supplementation showed no significant association in either direction.

The headline prevalence and most of the risk factors broadly fit clinical expectation, but two null results complicate the picture: regular exercise and calcium supplementation, both widely assumed to protect bone, showed no significant association here, even though lack of exercise did raise risk. The authors caution that the cohorts were predominantly East Asian, and mainly Chinese, so the figures may not transfer cleanly to other populations. Several factors also showed substantial disagreement between studies, which the reviewers managed statistically but could not eliminate. Whether these associations reflect cause and effect remains open, since the underlying studies followed women rather than testing interventions.

For a woman approaching or past menopause, this is a map of where the risk concentrates: time since menopause, number of births, smoking, inactivity, diabetes and any previous fracture all pointed the same way. It is also a reason not to assume a clean family history means low risk, since family history showed no significant link here. The strong protective association with oestrogen replacement therapy is worth knowing about as something to raise with a clinician, not a recommendation in itself. And the null result for calcium supplements is a reminder that the most heavily marketed answer is not necessarily the one the data flags.