A study of elderly stroke survivors in Japan has identified a link between vitamin D intake and hip fractures. The study was undertaken after statistics showed that the risk of hip fracture after stroke is two to four times that of a similar population who had not had a stroke.

The incidence of hip fracture was seven times greater in a group of elderly men who were severely deficient in vitamin D than among those who were less deficient. In those with sufficient levels of vitamin D, there were no hip fractures. All of the men had survived a stroke. They were assessed every two weeks for two years.

The men in the deficient group were older and severely immobilized, leading researchers to conclude that the combination of immobility and advanced age may cause vitamin D deficiency, which in turn leads to reduced bone mineral density and greater fracture risk.

Vitamin D deficiency leads to softening of the bones due to lack of minerals, most notably calcium. Hip fractures are associated with more deaths, disability, and medical costs than all other osteoporosis-related fractures combined.