More evidence links higher vitamin D levels with a reduced risk of death

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

6 Responses to More evidence links higher vitamin D levels with a reduced risk of death

  1. Paul Anderson 28 September 2009 at 11:59 am #

    In my opinion one of the best features of your blog is your persistance in following through an issue and the fact that you seek to address the underlying causes rather than focus upon treating symptoms.

    With regard to this particular post, unless I am mistaken, the upper nd well below optimum levels, suggesting:

    (i) Widespread vitamin D deficiency.
    (ii) That the possible increased benefits might be substantially higher in those with levels say above 60 ng/ml.

    It seems odd to me that the Govt (NHS) wil not fund the randomsied trials you (and others) advocatet, especially when considered alongside the recent initiatives to fast track cancer biopsies at an estimated cost of £1bn a year. The potential gains to health, and potential budget savings from the possible enhanced health benefits from higher vitamin D levels, would seem to make this a no brainer.

    I guess the absence of an effective patent (the patented vitamin D2 being less effective) and the current approach of treating sympoms rather than focusing on underlying causes seems to be the issue here.

    A situation not helped by the obsession with fat and cholesterol levels. Its seems as though the current approach of low fat diet and avoiding sunlight exposure is in fact aimed at minimising vitamin D levels.

    Will be interested to see how your levels progress over time.
    Do you also eat oily fish such as Mackeral, pilchards, etc. One of my ealier trawls through the area of heart disease and longevity identified Iceland as a country with low levels of heart disese and high ellves of mortality. presumably its no coincidence that oily fish are found in colder northern (and presumably Southern) hemispheres where it is difficult to prouduce adequate levels of vitamin D through the exposure of skin to sunlight.

  2. Ted Hutchinson 28 September 2009 at 1:19 pm #

    $40 £24 worldwide postal 25(OH)D testing from Grassrootshealth D Action
    55ng/ml or 135nmol/l associated with least chronic disease incidence and peak muscle performance and human breast milk replete with D3.

    Cheap 5000IU oil based gel cap D3 can be found online for $15 x 360 capsules.

    Calculator for those who want to know when/IF sunlight exposure produces Vitamin D3 Bear in mind this is for 1000iu only.
    1000iu required for each 25lbs you weigh.
    200lbs weight requires 8000iu/daily so needs to expose for 8 times as long or better still exposure 100% skin surface, as least tanned areas make most D3.
    The skin is the body’s largest organ, accounting for more than 10 percent of body mass, it’s a pity to prevent it functioning the way our DNA evolved.
    However the calculator tells me that today (28th Sept) with broken cloud it takes 43 minutes hand/face/arms midday exposure to make 1000iu using 100% skin surface rather than just 10% brings that down to about 5mins for 1000iu, so 30 mins for 6000iu (150lbs weight) but will it be warm enough?

  3. Jack 28 September 2009 at 11:54 pm #

    Dr. Briffa,

    While the ability to synthesize D3 from UVB rays typically decreases with age (even more so for those popping statins like candy), is it still possible for older folks to keep D levels optimized via sun exposure if they live in areas that allow for year-round sun bathing and if they expose a large enough portion of skin?

    Or is some measure of oral supplementation likely inevitable? I recognize that regular blood tests are the only way to know for certain how a given strategy is working, but I am just curious if aging invariably leds to sun exposure not being enough, regardless of how much you get.

  4. Ted Hutchinson 29 September 2009 at 8:30 pm #

    Serum 25-hydroxyvitamin D status of the US population: This is one of several papers showing 25(OH)D levels are getting lower in the general population, in Childrenand older people
    So although it is true that older skin is less able (because it generally has less cholesterol available to be converted, and older people may be less able/willing to go outside we must not think this is the root of the problem.
    this paper shows that the skin of patients of ALL ages responded to UVB therapy when dealing with vitiligo

    and this study links lower levels of 25(OH)D to urban pollution with rural women (ages 53~80yrs) having much higher 25(OH)D (79nmol/l) than urban women (47nmol/l) (ages 51~81)

    So the evidence is that living in areas of Urban tropospheric ozone increases the prevalence of vitamin D deficiency among older women with outdoor activities during summer but it’s clear from that research that older women living the the country areas were perfectly capable of making sufficient vitamin D to improve PTH levels.

  5. simona 1 October 2009 at 11:55 am #

    Thank you Ted

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