A Meta-Analysis pooling data from several earlier studies, has found that seniors may significantly reduce their risk of falls by taking vitamin D supplements. Only doses over 700 IU per day were found to be effective in reducing falls, say the researchers, who reported their findings in the October 2, 2009 issue of BMJ.

Approximately a third of people over the age of 65 have a fall each year. These falls result in a bone fracture about 6% of the time. In earlier studies, Vitamin D had been shown to help strengthen bones in older individuals, but its ability to reduce falls was not clear. The authors of the current review wished to determine what effect varying doses of both forms of the vitamin (D2 and D3) might have on risk of falling by looking at the data from eight previous studies. Vitamin D2 is the form of the vitamin made by plants; D3 is made in the skin after exposure to sunlight.

Vitamin D2 is the form of the vitamin made by plants; D3 is made in the skin after exposure to sunlight.

Doses of either D2 or D3 were found to reduce the risk of falls by 19%. Vitamin D3 itself was shown to reduce fall risk by up to 26%. However, only doses of 700−1000 IU per day were linked to reduced risk of falling: lower than 700 IU per day showed no association with number of falls.

The effect that was seen with the vitamin seemed to begin within just a few months of beginning the supplements.

The researchers also found that the active form of vitamin D showed no advantage over the supplemental form. The active form is more expensive and has been associated with elevated calcium levels in the blood (a condition known as hypercalcemia). One of the major roles of vitamin D is to aid calcium absorption and keep blood calcium levels constant.

The researchers urge those over 65 to take vitamin D supplements – in doses of at least 700−1000 IU per day, of course – but also say that more research will be needed to determine whether even higher doses might be more beneficial in reducing the risk of falls in seniors.

The study was led by H. A. Bischoff−Ferrari, who is affiliated with the University of Zurich and University Hospital in Zurich, Switzerland.