Dutch researchers have found that low vitamin D levels in people over 55 are associated with an inability to perform ordinary tasks of daily life. The researchers.studied two groups of older people — one of 725 men and women aged 55 to 65, and another of 1,237 older than 65 — to see if they could walk up or down a 15-step staircase, dress and undress, stand from a sitting position, cut their toenails, walk outside unaided for five minutes, and use their own or public transportation. Then they did blood tests for vitamin D levels.
After controlling for factors including age, physical activity and chronic diseases, they found that in both groups, a vitamin D level below 20 nanograms per milliliter was associated with an increased number of disabilities compared with those with a normal level (above 30).
The study was published online in The Journal of Clinical Endocrinology and Metabolism (July 19, 2013).