Graph of Predicted vs. observed serum 25-hydroxyvitamin D concentrations.

serum vitamin D ng/ ml in blood = (427.46(1+pigmentation grade)*10**-2 +(dose IU/day)*10**-2)/Body massindex,

that is: (430 * square root of (1+pigmentation grade) + square root of IU)/ Body massindex

pigmentation grade: 2 = light, 1= intermediate, 0 = dark),

body mass index = (weight lbs)(703)/(height inches)**2

• Click here for BMI calculator
• Equation does not consider other factors which will change change the response:
  • medical problems, supplements, vitamin A, latitude, smoking, how much get from the sun (time in the sun, age, ...__
• Click here for Smoking decrease vitamin D
• Equation appears to generally predict response correctly to within +-50%
• Vitamin D dose-response is not linear – Feb 2011 equation up to perhaps 140 ng
• Equation is based on data from 15-40 ng - doubt that this equation is correct for 60 ng
  • from: Serum 25-Hydroxyvitamin D and the Incidence of Acute Viral Respiratory Tract Infections in Healthy Adults June 2010
• Click here for PDF (file)

Based on 198 people in NE US in Fall and Winter 2009-2010

Close up view of the data

Need a vitamin D equation to account for:

Unhealthy people need even more vitamin D

And - the blood levels vary by 4X between individuals.

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See also VitaminDWiki

• Overview Vitamin D Dose-Response
• 4700 IU of vitamin D needed by most seniors – an equation -July 2014
• Higher BMI need more vitamin D – Oct 2010
• All items in category Predict Vitamin D 82 items
• 200 IU needed to increase vitamin D levels by 1 ng (not 100 IU) – summary of 25 studies – Feb 2014 which has the following chart