NEW YORK (Reuters Health) - Declining physical performance among some Dutch seniors may not be a simple consequence of aging, it may actually be due to a vitamin D deficiency, results of a new study suggest.
"Physicians and the general public should be made more aware of the high prevalence of vitamin D deficiency and insufficiency, and more effort should be concentrated on the early detection and treatment of people with suboptimal levels of vitamin D," study co-author Dr. Paul Lips, of VU University Medical Center in Amsterdam, and his colleagues write.
Previous research has shown that low vitamin D status is not uncommon among seniors, which may be explained by their decreased exposure to sunshine, reduced dietary consumption of vitamin D, and reduced capacity to naturally synthesize the vitamin. This deficiency is known to result in bone loss and fractures, among other bone and muscle-related problems.
The extent to which an individual's vitamin D status can affect his or her physical performance, however, has not been as well explored.
To investigate, Lips and his colleagues analyzed data on 979 seniors, 65 years or older, who were involved in the ongoing Longitudinal Aging Study Amsterdam.
They found that the study participants' vitamin D status was indeed associated with their physical performance, even after the seniors' age, the presence of chronic diseases, extent of alcohol consumption and various other factors were taken into account, they report in the Journal of Clinical Endocrinology & Metabolism.
For example, nearly half (47 percent) of the seniors had low vitamin D levels at the start of the study, and their deficiency was associated with poorer physical performance than their peers. Over the 3-year study, these vitamin D-deficient adults were also twice as likely as their peers to exhibit a decline in physical performance, such as taking longer to rise from a sitting position.
In light of these findings, "public health strategies should be aimed at this group," the researchers conclude.
The findings can also be generalized to other groups of older Dutch Caucasians, as well as to younger people, who may simply be better able to compensate for their vitamin D deficiency and subsequent decline in physical performance.
Vitamin D deficiency is not unique to the Dutch population, however. Dr. Nancy S. Wellman, a spokesperson for the American Society for Nutrition, told Reuters Health that "vitamin D is one of the most common shortfall nutrients in diets of older Americans."
"It is not found naturally in many foods," she explained.
To address this problem, Wellman, a professor and director of the National Resource Center on Nutrition, Physical Activity & Aging, at Florida International University, advises seniors to drink milk or orange juice that is fortified with vitamin D and calcium, since "both are needed for bone health."
SOURCE: Journal of Clinical Endocrinology & Metabolism, online June 2007.