4 ms·

This is close to the rate of vitamin D deficiency in the general population, e.g. https://www.ncbi.nlm.nih.gov/pubmed/21310306 https://www.ncbi.nlm.nih.gov/pubm

This is close to the rate of vitamin D deficiency in the general population, e.g. https://www.ncbi.nlm.nih.gov/pubmed/21310306 https://www.ncbi.nlm.nih.gov/pubmed/21310306

tfehring 8y ago
The study you linked was based on a threshold of 50 nmol/L, while the originally posted study used two thresholds, 30 nmol/L and 50 nmol/L. At the 50 nmol/L cutoff, the study you linked indicates a deficiency rate of 41.6% for the general population, compared to a rate of 91.3% among psychiatric patients according to the posted study. I’d still take the posted study with a grain of salt. Vitamin D deficiency between individuals is likely to be highly correlated within a particular region and time period due to its dependence on weather, and the authors didn’t control for that. But they did say that this was just a pilot, and given the effect size it’s probably worth investigating further. Edit: fixed units
- petra 8y ago
  Regarding the weather: most people most often stay indoors or in cars(does the glass filter the Vitmain-D causing rays), and usually wear long pants and a shirt, so only a small body area is exposed to the sun, so it's possible that even in summer, people suffer from Vitamin-D deficiency.
  - tfehring 8y ago
    Yeah, absolutely - most regions probably have a nonzero population with Vitamin D deficiency year-round. But if I had to pick a place and time at which the overall rate of Vitamin D deficiency is high, the UK in February through April seems like a safe bet.
  - mikehotel 8y ago
    Be careful with increased exposure to sunlight. UV is a known carcinogen. https://www.cancer.org/cancer/cancer-causes/radiation-exposure/uv-radiation/uv-radiation-does-uv-cause-cancer.html https://www.cancer.org/cancer/cancer-causes/radiation-exposu... There are safer sources of vitamin D.
    - ovao 8y ago
      To this end, I strongly suggest checking your local UV index before heading outdoors for any extended period of time. I use an iOS app called UVLens (no affiliation), which displays your local UV index throughout the day and can give you an estimate of how long before you’ll burn (based on skin color, eye color, etc.) Provided you’re taking reasonable precautions, limited exposure to broad-spectrum UV is quite safe.
      - walshemj 8y ago
        You just need to slap on some suntan location if its going to be sunny - which what I do to counter the increased risk due to meds I have to take
- jimrandomh 8y ago
  More important difference: the base rate in the grandparent post is for the US, while the psychiatric hospital admission study is for hospitals in the UK. Serum vitamin D depends significantly on sunlight exposure and hence latitude, so the base rate is different there.
  - tfehring 8y ago
    I agree, good point. See m4burns’s comment, which includes a link to broader UK data.
- m4burns 8y ago
  Good points. Here is some data on vitamin D deficiency in the UK (where the original study was conducted) that also addresses seasonality: https://www.bjfm.co.uk/prevention-of-vitamin-d-deficiency https://www.bjfm.co.uk/prevention-of-vitamin-d-deficiency "Low serum levels of vitamin D are found in significant numbers of all population groups in the UK: in winter 30-40% of all age groups in the general population are classed as vitamin D deficient. Even towards the end of summer 8% of adults and 13% of adolescents remain deficient." where deficient is defined as < 25 nmol/L of 25(OH)D
  - tfehring 8y ago
    Thanks for the link. Seems like the posted study’s results are very similar to the deficiency rates for the overall UK population in winter. (Their data was collected between February and April.)
xutopia 8y ago
I came here to say that it didn't compare to general population.

This is close to the rate of vitamin D deficiency in the general population, e.g. https://www.ncbi.nlm.nih.gov/pubmed/21310306 https://www.ncbi.nlm.nih.gov/pubmed/21310306

tfehring 8y ago

The study you linked was based on a threshold of 50 nmol/L, while the originally posted study used two thresholds, 30 nmol/L and 50 nmol/L. At the 50 nmol/L cutoff, the study you linked indicates a deficiency rate of 41.6% for the general population, compared to a rate of 91.3% among psychiatric patients according to the posted study. I’d still take the posted study with a grain of salt. Vitamin D deficiency between individuals is likely to be highly correlated within a particular region and time period due to its dependence on weather, and the authors didn’t control for that. But they did say that this was just a pilot, and given the effect size it’s probably worth investigating further. Edit: fixed units

petra 8y ago
Regarding the weather: most people most often stay indoors or in cars(does the glass filter the Vitmain-D causing rays), and usually wear long pants and a shirt, so only a small body area is exposed to the sun, so it's possible that even in summer, people suffer from Vitamin-D deficiency.
- tfehring 8y ago
  Yeah, absolutely - most regions probably have a nonzero population with Vitamin D deficiency year-round. But if I had to pick a place and time at which the overall rate of Vitamin D deficiency is high, the UK in February through April seems like a safe bet.
- mikehotel 8y ago
  Be careful with increased exposure to sunlight. UV is a known carcinogen. https://www.cancer.org/cancer/cancer-causes/radiation-exposure/uv-radiation/uv-radiation-does-uv-cause-cancer.html https://www.cancer.org/cancer/cancer-causes/radiation-exposu... There are safer sources of vitamin D.
  - ovao 8y ago
    To this end, I strongly suggest checking your local UV index before heading outdoors for any extended period of time. I use an iOS app called UVLens (no affiliation), which displays your local UV index throughout the day and can give you an estimate of how long before you’ll burn (based on skin color, eye color, etc.) Provided you’re taking reasonable precautions, limited exposure to broad-spectrum UV is quite safe.
    - walshemj 8y ago
      You just need to slap on some suntan location if its going to be sunny - which what I do to counter the increased risk due to meds I have to take
jimrandomh 8y ago
More important difference: the base rate in the grandparent post is for the US, while the psychiatric hospital admission study is for hospitals in the UK. Serum vitamin D depends significantly on sunlight exposure and hence latitude, so the base rate is different there.
- tfehring 8y ago
  I agree, good point. See m4burns’s comment, which includes a link to broader UK data.
m4burns 8y ago
Good points. Here is some data on vitamin D deficiency in the UK (where the original study was conducted) that also addresses seasonality: https://www.bjfm.co.uk/prevention-of-vitamin-d-deficiency https://www.bjfm.co.uk/prevention-of-vitamin-d-deficiency "Low serum levels of vitamin D are found in significant numbers of all population groups in the UK: in winter 30-40% of all age groups in the general population are classed as vitamin D deficient. Even towards the end of summer 8% of adults and 13% of adolescents remain deficient." where deficient is defined as < 25 nmol/L of 25(OH)D
- tfehring 8y ago
  Thanks for the link. Seems like the posted study’s results are very similar to the deficiency rates for the overall UK population in winter. (Their data was collected between February and April.)

xutopia 8y ago

I came here to say that it didn't compare to general population.