At the end of April, I wrote about research which assessed the relationship between vitamin D status and physical function in a group of elderly individuals . Briefly, the results of this study found that lower vitamin D levels were found to associated with lower muscular strength and physical function in both men and women. I made the point that this may mean that getting out in the sun (sunlight stimulates vitamin D production in the skin) may be one simple and free way for individuals to maintain their physical powers in old age.
More recently, other research has come to light that suggests that vitamin D may have a crucial role to play in physical function for the elderly. Researchers based in Amsterdam, the Netherlands, assessed the relationship between blood vitamin D levels and physical performance in a group of 1234 men and women aged 65 or older . The researchers not only measured physical performance, but also any decline in that performance over a 3-year period.
In the analysis, the researchers compared the results obtained from individuals with vitamin D levels of less than 10 ng/ml (nanograms per millilitre of blood) and 10-20 ng/ml with the results of those whose levels were higher than 30 ng/ml.
The researchers found that physical performance was lower in the individuals with vitamin D levels of less than 10 and 10-20 ng/ml compared to those with levels greater than 30 ng/ml. The results of studies of this nature may be affected by other factors such as presence of chronic disease, body weight and alcohol consumption. These factors were taken into account in the analysis in an attempt to isolate vitamin D levels as the only significant variable.
Having done this, they found that the risk of physical function decline over the 3-year period of the study was about twice in individuals with lower vitamin D levels compared with those with higher levels. The authors of this study concluded that blood levels of vitamin D of less than 20 ng/ml are associated with poorer physical performance and greater decline in physical performance in older men and women.
The results of this study add to the growing body of evidence linking vitamin D and improved health, including in elderly individuals. I sometimes wish that this sort of evidence got a bit more coverage. After all, sunlight exposure (the main source of vitamin D in the body) is not only health-promoting but free. I wonder if one of the reasons that this sort of research does not generally get the attention it deserves is because there’s no money in it.
1. Houston DK, et al. Association Between Vitamin D Status and Physical Performance: The InCHIANTI Study. J Gerontol A Biol Sci Med Sci. 2007;62(4):440-6.
2. Wicherts IS, et al. Vitamin D status predicts physical performance and its decline in older persons. J Clin Endocrinol Metab. 2007;92(6):2058-65