Sweden has one of the highest incidences of frailty fractures in the world, with a lifetime cumulative incidence of 50% in women and 25% in men.1,2 The risk of hip fracture, the most devastating fragility fracture, increases 44-fold in Swedish women from 55 to 85 years of age, so the lifetime risk of hip fracture is 25% in women and 12% in men.2 Although osteoporosis, low bone mineral density (BMD) is a strong risk factor for fractures,3 less than one in three hip fractures is attributable to osteoporosis,4 and for other types of frailty fractures, the proportion is even lower. Depending on the country, the average residual lifetime risk of hip fracture for women at 50 years of age is 10-25%, with the highest risk found in northern Europe.5 It is a significant cause of disability and mortality in older people, for whom it is associated with low quality of life and long-term need for institutional care.(3,4) Because of population aging, the total health loss due to hip fractures is estimated to double in the next two decades.(5) There is thus an urgent need to understand and mitigate the causes of hip fracture.