Bone Density and Osteopenia: Why Prevention Starts Decades Before Menopause

Osteopenia describes bone mineral density lower than the norm for a young, healthy adult, but still not meeting the criteria for osteoporosis — on a bone density scan (DEXA), this corresponds to a T-score between -1.0 and -2.5. It's an intermediate, statistical description rather than a disease in itself, but men and women with osteopenia have significantly elevated fracture risk compared to normal bone density, and some of them progress to osteoporosis over time.

A key, often overlooked fact: most people reach peak bone mass between ages 25 and 30, after which bone density slowly but steadily declines. That means the higher the peak bone mass built in youth, the more "bone capital" remains for the decades of natural loss that follow — which shifts prevention out of the perimenopausal period and back decades earlier, to a time when hardly anyone thinks about bone health.

The US Preventive Services Task Force (USPSTF), one of the most influential preventive-guidelines bodies, recommends routine bone density scanning (DEXA) for all women from age 65, and for younger postmenopausal women if at least one additional risk factor is present (low body weight, family history of fracture, smoking, long-term glucocorticoid use). Its 2025 guideline update shifted emphasis toward DEXA itself as the risk-assessment method for younger postmenopausal women with risk factors, replacing the previously recommended questionnaire-based risk calculators.

For men, the guidance is less clear-cut — the USPSTF states there isn't enough evidence to recommend for or against routine screening, which doesn't mean there's no risk, just insufficient population-level research in this group. In practice, this means the decision to get a DEXA scan in men more often rests on individual risk-factor assessment than on a fixed age threshold.

For years, women with low bone density were mainly, cautiously advised to do gentle movement, out of concern about fracture risk during intense exertion. The LIFTMOR trial from Australia challenged that approach by directly testing whether supervised, high-intensity resistance training is safe and effective in exactly this group.

LIFTMOR studied postmenopausal women with already-detected low bone mass. The question of early prevention, though, requires looking at younger women, where the goal is building the highest possible peak bone mass rather than reversing loss that's already occurred.

The effect in younger women is statistically significant but clearly smaller than in the LIFTMOR trial of postmenopausal women with already-reduced bone mass — which makes physiological sense: bone starting from a lower baseline statistically has more "room" to improve under mechanical stimulus. That doesn't diminish the importance of regular bone-loading activity at a younger age, though — this is about building peak bone mass, an effect that can't be fully recreated later, not about reversing loss that's already happened.

A second widespread myth is the belief that calcium and vitamin D supplementation alone is enough to significantly lower fracture risk — as the WHI trial shows, the effect is real but more modest than supplement advertising suggests, and most effective combined with regular, bone-loading training rather than as a standalone strategy.

Bone density is one of those areas of health where the biggest mistake is waiting for a warning sign instead of acting preventively. The evidence points consistently in one direction: regular, bone-loading training has a documented effect both in younger women building peak bone mass and in postmenopausal women with already-reduced density, and calcium and vitamin D supplementation has its place, but as a complement to diet and physical activity, not a standalone high-dose solution. A DEXA scan done earlier than the standard recommended age of 65, in people with risk factors, provides a valuable reference point for the future.