A group of researchers recently published a study that is of interest to the elderly.
Houston DK et al. Low 25-Hydroxyvitamin D Predicts the Onset of Mobility Limitation and Disability in Community-Dwelling Older Adults: The Health ABC Study. Journal of Gerontology: Medical Science; April 2012.
The main objective of this research study was to evaluate the link between vitamin D status and the onset of limitations in physical function in elderly, using data from the Health, Aging, and Body Composition (Health ABC) Study.
This 6 year study, published in April 2012 issue of “Journal of Gerontology” was conducted by a team of researchers led by Dr. Denise Houston from the Wake Forest School of Medicine in North-Carolina.
Physical functions/limitations evaluated in this study included:
1. Persistent mobility limitations defined as two consecutive reports of having difficulty walking one fourth of a mile or climbing 10 steps without resting
2. Persistent mobility disability defined as two consecutive reports of having severe difficulty or inability to walk one fourth of a mile or climb 10 steps without resting
This study included 2099 subjects who were initially well functioning, without physical limitations. The mean age was 74.6 years, and the study included both men and women, with Caucasian and African American background. The onset of mobility limitation and disability were assessed every 6 months and every year over a 6 year period.
At the beginning of the study 28.9% of the subjects had a 25(OH)D (vitamin D level) below 20 ng/ml, 36.1% had a 25(OH)D between 20 and 30 ng/ml and only 35% had a 25(OH)D of 30 ng/ml or higher.
The investigators found that a 25(OH)D below 30 ng/ml was associated with an approximately 30% increased risk of mobility limitation among older adults and an approximately two times increased risk of disability among those with 25(OH)D levels below 20 ng/ml.
Previous research studies found that low vitamin D status may speed up the disability process in two ways: firstly, it affects the function of the muscles, and secondly, it influences the onset of medical conditions such as diabetes, high blood pressure, heart and lung diseases, and osteoarthritis. Other studies found that vitamin D deficiency may be associated with lower physical performance and strength in elderly. Another recent study revealed that low 25(OH)D was linked with the occurrence of mobility limitations over a 3 year follow up among older subjects.
Given these study’s findings, elderly may want to monitor their vitamin D status more closely to delay the onset of disability or decreased mobility. Those with levels above 30 ng/ml had a decreased risk of these problems compared to those below 30 ng/ml, and especially compared to those below 20 ng/ml.