A large observational study of older adults in Hong Kong has found that commonly prescribed osteoporosis drugs, known as nitrogen-containing bisphosphonates (NBPs), are associated with a significantly reduced risk of Alzheimer's disease and other dementias. The finding adds to growing evidence of a "bone-brain axis" linking skeletal health to cognitive decline, though researchers caution the results do not prove the drugs actually prevent dementia and stop short of recommending their use for that purpose.

The study followed 121,492 adults aged 60 and over who had recently been diagnosed with osteoporosis or suffered a serious fracture, none of whom had previously taken osteoporosis medication. Those using NBPs, such as alendronate, ibandronate, risedronate and zoledronate, had a 16% lower risk of developing Alzheimer's and related dementias than non-users, and a 24% lower risk than those taking other osteoporosis drugs. Published in Alzheimer's & Dementia, the study was limited by its focus on a single Chinese population, the absence of baseline cognitive testing, and missing data on fracture severity and supplement use, meaning the authors are calling for clinical trials to confirm whether the drugs genuinely lower dementia risk.