Earlier this month I blogged about a study which found that supplementing elderly individuals with vitamin D was found to enhance their muscle strength. This has at least some relevance because as people age, they can tend to go out less, and therefore be a particular risk for vitamin D deficiency. Vitamin D deficiency is linked not just with muscle weakness, but impaired balance too. Such factors can lead to a degree of infirmity and disability that make venturing out even less likely. Such a viscous cycle can be difficult to escape.
The potential importance of adequate vitamin D levels in the elderly was raised again, recently, in the form of a study which focused the relationship of this nutrient with overall risk of death [1]. In this study, conducted in America, vitamin D levels were checked in 714 women aged 70-79. The women were followed for an average of 6 years. During this time, 100 (14 per cent) of women diet.
The women were split into four groups (quartiles), according to vitamin D levels. Those in the lowest quartile (vitamin D levels less than 15.3 ng/ml) were found to be about 2 and a half times more likely to die than women in the highest quartile (vitamin D levels more than 27 ng/ml).
We don’t know from this sort of study whether there is a causal relationship between vitamin D levels and risk of death. However, bearing in mind the wealth of evidence linking higher vitamin D levels with a reduced risk of several chronic conditions, there is at least some reason for thinking that it might be. Also, there are several other studies, now, that link low vitamin D levels with an enhanced risk of death. See relatively recent blog posts here, here and here for examples. And on top of this, we have one study in which vitamin D supplementation was linked with a reduced risk of death [2].
As I said before, what I think is required now is for randomised controlled trials to assess whatever potential vitamin D may have to reduce risk of disease and death. In the meantime, I am continuing to attempt to optimise my vitamin D levels with a combination of sun exposure and supplementation.
References:
1. Semba RD, et al. Low serum 25-hydroxyvitamin D concentrations are associated with greater all-cause mortality in older community-dwelling women. Nutr Res 2009;29(8):525-530
2. Autier P, et al. Vitamin D supplementation and total mortality. Arch Int Med 2007;167:1730-1737
